UFOs Northwest
Sat, 04 Jul 2009 16:27 UTC
Posted: July 4, 2009
Date of Sighting: July 2, 2009
Time of Sighting: 10 PM MDT
Location of Sighting: Longmont, Colorado (About 20 Miles North of Denver)
Description: My partner and I were driving East to Longmont on Highway 66 (Ute Highway) from Lyons, Colorado and saw a giant fireball in the sky, hiding behind a large section of storm clouds. At first I thought it was the moon, but suddenly it came out from behind the clouds and rapidly decreased in altitude. Once it began decreasing in altitude, it starting breaking up into smaller pieces-- two, then three and then four. As soon as it began breaking up, they began flying in formation to the West (thus eliminating the option of it being a meteor due to it's trajectory). About 30 seconds later, 4 of the pieces began falling to the ground (each piece also had very long tails, similar to a meteor). As they were falling, two of the pieces jutted off to the left, while the other two jutted to the right. One by one, they fell to the ground in a blaze.
My fiance and I smelled smoke as well around the area. We estimated the distance between us and the phenomena to be roughly 3 miles or so to the South of us. It was certainly not fireworks due to it's behavior. There has been nothing in the newspapers today in reference to the occurrence.
Note: We received another similar report from Longmont near the same time. Some of the above report suggests space junk or a meteor breaking up, but the witnesses indicate that the trajectory changed indicating the objects could have been under intelligent control. The fact that smoke odor occurred could mean that the object crashed. However, the odor could be due to fireworks activity. Anyone else viewing these lights is urged to file a report.
Date of Sighting: July 2, 2009
Time of Sighting: 10 PM MDT
Location of Sighting: Longmont, Colorado (About 20 Miles North of Denver)
Description: My partner and I were driving East to Longmont on Highway 66 (Ute Highway) from Lyons, Colorado and saw a giant fireball in the sky, hiding behind a large section of storm clouds. At first I thought it was the moon, but suddenly it came out from behind the clouds and rapidly decreased in altitude. Once it began decreasing in altitude, it starting breaking up into smaller pieces-- two, then three and then four. As soon as it began breaking up, they began flying in formation to the West (thus eliminating the option of it being a meteor due to it's trajectory). About 30 seconds later, 4 of the pieces began falling to the ground (each piece also had very long tails, similar to a meteor). As they were falling, two of the pieces jutted off to the left, while the other two jutted to the right. One by one, they fell to the ground in a blaze.
My fiance and I smelled smoke as well around the area. We estimated the distance between us and the phenomena to be roughly 3 miles or so to the South of us. It was certainly not fireworks due to it's behavior. There has been nothing in the newspapers today in reference to the occurrence.
Note: We received another similar report from Longmont near the same time. Some of the above report suggests space junk or a meteor breaking up, but the witnesses indicate that the trajectory changed indicating the objects could have been under intelligent control. The fact that smoke odor occurred could mean that the object crashed. However, the odor could be due to fireworks activity. Anyone else viewing these lights is urged to file a report.
Technology Review
Wed, 01 Jul 2009 07:21 UTC
The
ratio of nitrogen isotopes in several comets almost exactly matches the
ratio on Earth, implying that our early atmosphere probably came from a
cometary bombardment.
Astrobiologists have long puzzled over the origin of Earth's oceans. But they've dwelt a little less long over a related question: where does the nitrogen in our atmosphere come from? Now a new analysis by Damien Hutsemekers and pals at the Universite de Liege, in Belgium, suggests an answer to both questions.
One of the most attractive theories of the origin of our water is that Earth was once bombarded by icy comets that left a watery residue. The trouble is that the ratio of deuterium to hydrogen in water on Earth is much lower than it is in the few comets we've been able to measure it in (i.e., Halley, Hyakutake, Hale-Bopp, and C/2002 T7 LINEAR). So if these types of comets, which we know came from the Oort Cloud, did supply Earth's water, it must have mixed with water already on Earth that had a very low deuterium content.
Now Hutsemekers and co have put a different kind of constraint on the cometary contribution by measuring nitrogen isotopes. They say that comets must deliver water and nitrogen together (although they don't say why), so a comparison of nitrogen isotopes can also place limits on the amount of water that must have been delivered.
Their conclusion is that "no more than a few percent of Earth's water can be attributed to comets."
But that's not the end of the story. Interestingly, they say that the ratio of nitrogen-14 to nitrogen-15 in cyanide and hydrogen cyanide in comets almost exactly matches that on Earth. "A significant part of Earth's atmospheric nitrogen might come from comets," they conclude.
That's any exciting result because it implies a dual origin for our oceans and atmosphere.
Of course, the huge fly in this hypothetical ointment is that there may well be other types of comet out there that have hydrogen to deuterium ratios as well as nitrogen isotope ratios that more closely match our own.
But in the meantime, the idea that comets gave us our early atmosphere is cool enough to keep us a-wonderin' for a while.
Ref: arxiv.org/abs/0906.5221: New Constraints on the Delivery of Cometary Water and Nitrogen to Earth from the 15N/14N Isotopic Ratio
Astrobiologists have long puzzled over the origin of Earth's oceans. But they've dwelt a little less long over a related question: where does the nitrogen in our atmosphere come from? Now a new analysis by Damien Hutsemekers and pals at the Universite de Liege, in Belgium, suggests an answer to both questions.
One of the most attractive theories of the origin of our water is that Earth was once bombarded by icy comets that left a watery residue. The trouble is that the ratio of deuterium to hydrogen in water on Earth is much lower than it is in the few comets we've been able to measure it in (i.e., Halley, Hyakutake, Hale-Bopp, and C/2002 T7 LINEAR). So if these types of comets, which we know came from the Oort Cloud, did supply Earth's water, it must have mixed with water already on Earth that had a very low deuterium content.
Now Hutsemekers and co have put a different kind of constraint on the cometary contribution by measuring nitrogen isotopes. They say that comets must deliver water and nitrogen together (although they don't say why), so a comparison of nitrogen isotopes can also place limits on the amount of water that must have been delivered.
Their conclusion is that "no more than a few percent of Earth's water can be attributed to comets."
But that's not the end of the story. Interestingly, they say that the ratio of nitrogen-14 to nitrogen-15 in cyanide and hydrogen cyanide in comets almost exactly matches that on Earth. "A significant part of Earth's atmospheric nitrogen might come from comets," they conclude.
That's any exciting result because it implies a dual origin for our oceans and atmosphere.
Of course, the huge fly in this hypothetical ointment is that there may well be other types of comet out there that have hydrogen to deuterium ratios as well as nitrogen isotope ratios that more closely match our own.
But in the meantime, the idea that comets gave us our early atmosphere is cool enough to keep us a-wonderin' for a while.
Ref: arxiv.org/abs/0906.5221: New Constraints on the Delivery of Cometary Water and Nitrogen to Earth from the 15N/14N Isotopic Ratio
Shirley Bartynek
Hamilton Advertiser
Thu, 02 Jul 2009 16:43 UTC
A strange object was seen in the skies above Whitehill in Hamilton on Tuesday night.
A young Hamilton woman captured this picture on her mobile phone of what she described to be a "fireball" at about 11pm.
Natalie Smith was dropping her friend back home in James Murdie Gardens when she noticed the unusual-looking orange glow in the sky.
The 20-year-old South Lanarkshire Council clerical assistant explained: "We were both sitting inside my car when we noticed something in the sky.
"It looked like a fireball, like a big piece of ash, but it was the size of a football. It had an orange glow. We sat and watched it for a bit but when I went to drive away it disappeared behind the trees at Whistleberry Road.
"I have no idea what it was it was just a strange sight to see."
Natalie, who lives in Burnbank, headed back in her car to drop another friend off at Eddlewood before returning home that evening.
It is not known if atmospheric conditions could have been responsible for the light's sudden appearance.
A young Hamilton woman captured this picture on her mobile phone of what she described to be a "fireball" at about 11pm.
Natalie Smith was dropping her friend back home in James Murdie Gardens when she noticed the unusual-looking orange glow in the sky.
The 20-year-old South Lanarkshire Council clerical assistant explained: "We were both sitting inside my car when we noticed something in the sky.
"It looked like a fireball, like a big piece of ash, but it was the size of a football. It had an orange glow. We sat and watched it for a bit but when I went to drive away it disappeared behind the trees at Whistleberry Road.
"I have no idea what it was it was just a strange sight to see."
Natalie, who lives in Burnbank, headed back in her car to drop another friend off at Eddlewood before returning home that evening.
It is not known if atmospheric conditions could have been responsible for the light's sudden appearance.
Bernie Reim
Morning Sentinel
Sat, 27 Jun 2009 13:32 UTC
Summer is now upon us and this will be a good month to enjoy the sky in
spite of the short nights. The bright planets are evenly split this
month, with the gas giants Saturn and Jupiter visible in the evening
sky and our neighboring terrestrial planets, Venus and Mars, visible in
the morning sky.
There will be two more very exciting celestial events taking place this month, but only one of them will be visible for us in New England. The annual Delta Aquarid Meteor Shower will peak during the morning hours of July 28. This shower actually begins around the middle of July and blends right into the famous Perseid Meteor Shower, which starts at the end of July and peaks on August 12.
Caused by Comet Machholz, you can expect around 15 to 20 Delta Aquarids per hour that morning. The moon will be first quarter and will set around midnight. Meteor showers are usually better after midnight, anyway, since that is when the earth is spinning directly into the meteors, like snowflakes on the front windshield of your car during a snowstorm. The whole earth can be seen as a little spaceship continually orbiting the sun at 18.6 miles per second, or 67,000 miles per hour.
I remember seeing Comet Machholz, the 10th comet discovered by Don Machholz of California, in the morning sky with binoculars near the Pleiades in January 1996. These meteors will appear to originate from a point in the sky in Aquarius low on the southeastern sky just above the 17th-brightest star in the sky named Fomalhaut, located 25 light years from Earth.
When you look at that star this summer, remember that the very first planet ever seen directly in visible light was just found orbiting this star using the Hubble Space Telescope late last year. It is a Jupiter-sized planet that orbits Fomalhaut at a much greater distance than Jupiter is from our sun since it takes that planet, called Fomalhaut B, about 872 years to orbit its parent star. It was found just inside the edge of a huge disk of dust, and it was predicted to exist there for a while, since they studied this star for eight years before they finally found its planet in visible light.
The other major event will be a total eclipse of the sun. That will happen July 22 over India and China. The narrow shadow cone of the moon will sweep across the earth that day starting just north of Mumbai, India, continuing over Bhutan and across southern China exiting in Shanghai, the biggest city in China with 20 million people.
Bhutan, located on the rooftop of the world next to Nepal, is a very interesting country that has successfully balanced modernization with preserving ancient culture and the environment under the guiding philosophy of Gross National Happiness. It's the only country in the world to actually measure this elusive human quality.
At least one member of our astronomy club, The Astronomical Society of Northern New England, will be going to China for this eclipse, so I will update you next month on what they experienced. Try to catch this eclipse live on the NASA channel or a live feed on the Internet.
I remember seeing the last total solar eclipse live on the NASA channel from Mongolia at 7 a.m. last Aug. 1. Actually being there to experience a total eclipse of the sun and physically standing in the shadow of the moon, our only natural satellite is one of the most exciting and memorable experiences in astronomy anyone could ever have. The next total solar eclipse happens on July 11, 2010, right over Easter Island in the south Pacific, and the next one in this country doesn't happen until Aug. 21, 2017.
Saturn is beginning to sink into the western horizon and will be setting by 10 p.m. Through a telescope you will notice that the angle of its rings is getting ever thinner, reaching just 2 degrees from horizontal by the end of the month. Look for a slender waxing crescent moon to glide under Regulus and Saturn about 30 minutes after sunset from July 23 to 25.
Jupiter begins the month rising by 11 p.m. and ends the month rising by 9 p.m., just after sunset. The King of the Planets will rise at sunset by the middle of August, when it reaches opposition. Jupiter continues to get a little brighter and closer each night until that time. Notice that you can see its four large Galilean moons with just a pair of good binoculars.
The rest of the planetary action takes place in our morning sky about one hour before sunrise. Orange Mars can be seen just below the Pleiades and brilliant Venus is below and to the left of our other neighbor, and just to the left of Aldebaran, an orange star in Taurus. Venus is 100 times brighter than Mars and over 3 times as large in our sky.
However, Mars is slowly getting closer and brighter and Venus is getting less bright and farther away, even though it is getting more illuminated by the sun now, similar to a waxing gibbous moon. Watch the drama in the morning sky between July 17 and 19 as a waning crescent moon drifts through the Pleiades right above Mars and Venus.
Friday. The earth is at aphelion or farthest from the sun at 10 tonight. Our orbit around the sun traces an elliptical shape, but it is not very different from a circle since we will be just 3.3 percent farther from the sun now than we are in January. Our seasons are caused by the 23.5-degree tilt of the earth and not our distance from the sun. The waxing gibbous moon will pass very close to Antares tonight. If you were in Hawaii, you would see the moon cover this bright star tonight around midnight. Antares, a red supergiant star, is the 16th-brightest star in the sky and one of the largest stars in our whole galaxy of 200 billion stars. Antares is 700 times the diameter of our sun and 10,000 times brighter than our sun. Antares is 600 light years away, but if you could place it were our sun is in the sky, the orbit of Earth and even Mars would be inside the star below the surface.
July 7. Full moon is at 5:21 a.m. This is also called the Hay or Thunder Moon.
July 9. Jupiter will be near the moon tonight and the next night in the constellation of Capricornus. Through a small telescope you can see Neptune just to the north-northwest.
July 15. Last quarter moon is at 5:53 p.m.
July 16. On this day in 1994, the first fragment of Comet Shoemaker-Levy 9 hit Jupiter. After that 20 more mile-wide fragments plowed into Jupiter's gas surface during the next six days, one hitting about every six hours. I watched through a telescope as five of those 21 fragments hit Jupiter, but since they actually hit on the far side of Jupiter, I could not see them until about 30 minutes later as they rotated into view. One of many surprises that these impacts created were the large and easily visible (even in a small telescope) earth-sized black spots that remained visible for many months after the original impacts.
July 21. New moon is at 10:35 p.m.
July 28. First quarter moon is at 6 p.m. and the Delta Aquarid meteor shower peaks.
There will be two more very exciting celestial events taking place this month, but only one of them will be visible for us in New England. The annual Delta Aquarid Meteor Shower will peak during the morning hours of July 28. This shower actually begins around the middle of July and blends right into the famous Perseid Meteor Shower, which starts at the end of July and peaks on August 12.
Caused by Comet Machholz, you can expect around 15 to 20 Delta Aquarids per hour that morning. The moon will be first quarter and will set around midnight. Meteor showers are usually better after midnight, anyway, since that is when the earth is spinning directly into the meteors, like snowflakes on the front windshield of your car during a snowstorm. The whole earth can be seen as a little spaceship continually orbiting the sun at 18.6 miles per second, or 67,000 miles per hour.
I remember seeing Comet Machholz, the 10th comet discovered by Don Machholz of California, in the morning sky with binoculars near the Pleiades in January 1996. These meteors will appear to originate from a point in the sky in Aquarius low on the southeastern sky just above the 17th-brightest star in the sky named Fomalhaut, located 25 light years from Earth.
When you look at that star this summer, remember that the very first planet ever seen directly in visible light was just found orbiting this star using the Hubble Space Telescope late last year. It is a Jupiter-sized planet that orbits Fomalhaut at a much greater distance than Jupiter is from our sun since it takes that planet, called Fomalhaut B, about 872 years to orbit its parent star. It was found just inside the edge of a huge disk of dust, and it was predicted to exist there for a while, since they studied this star for eight years before they finally found its planet in visible light.
The other major event will be a total eclipse of the sun. That will happen July 22 over India and China. The narrow shadow cone of the moon will sweep across the earth that day starting just north of Mumbai, India, continuing over Bhutan and across southern China exiting in Shanghai, the biggest city in China with 20 million people.
Bhutan, located on the rooftop of the world next to Nepal, is a very interesting country that has successfully balanced modernization with preserving ancient culture and the environment under the guiding philosophy of Gross National Happiness. It's the only country in the world to actually measure this elusive human quality.
At least one member of our astronomy club, The Astronomical Society of Northern New England, will be going to China for this eclipse, so I will update you next month on what they experienced. Try to catch this eclipse live on the NASA channel or a live feed on the Internet.
I remember seeing the last total solar eclipse live on the NASA channel from Mongolia at 7 a.m. last Aug. 1. Actually being there to experience a total eclipse of the sun and physically standing in the shadow of the moon, our only natural satellite is one of the most exciting and memorable experiences in astronomy anyone could ever have. The next total solar eclipse happens on July 11, 2010, right over Easter Island in the south Pacific, and the next one in this country doesn't happen until Aug. 21, 2017.
Saturn is beginning to sink into the western horizon and will be setting by 10 p.m. Through a telescope you will notice that the angle of its rings is getting ever thinner, reaching just 2 degrees from horizontal by the end of the month. Look for a slender waxing crescent moon to glide under Regulus and Saturn about 30 minutes after sunset from July 23 to 25.
Jupiter begins the month rising by 11 p.m. and ends the month rising by 9 p.m., just after sunset. The King of the Planets will rise at sunset by the middle of August, when it reaches opposition. Jupiter continues to get a little brighter and closer each night until that time. Notice that you can see its four large Galilean moons with just a pair of good binoculars.
The rest of the planetary action takes place in our morning sky about one hour before sunrise. Orange Mars can be seen just below the Pleiades and brilliant Venus is below and to the left of our other neighbor, and just to the left of Aldebaran, an orange star in Taurus. Venus is 100 times brighter than Mars and over 3 times as large in our sky.
However, Mars is slowly getting closer and brighter and Venus is getting less bright and farther away, even though it is getting more illuminated by the sun now, similar to a waxing gibbous moon. Watch the drama in the morning sky between July 17 and 19 as a waning crescent moon drifts through the Pleiades right above Mars and Venus.
Friday. The earth is at aphelion or farthest from the sun at 10 tonight. Our orbit around the sun traces an elliptical shape, but it is not very different from a circle since we will be just 3.3 percent farther from the sun now than we are in January. Our seasons are caused by the 23.5-degree tilt of the earth and not our distance from the sun. The waxing gibbous moon will pass very close to Antares tonight. If you were in Hawaii, you would see the moon cover this bright star tonight around midnight. Antares, a red supergiant star, is the 16th-brightest star in the sky and one of the largest stars in our whole galaxy of 200 billion stars. Antares is 700 times the diameter of our sun and 10,000 times brighter than our sun. Antares is 600 light years away, but if you could place it were our sun is in the sky, the orbit of Earth and even Mars would be inside the star below the surface.
July 7. Full moon is at 5:21 a.m. This is also called the Hay or Thunder Moon.
July 9. Jupiter will be near the moon tonight and the next night in the constellation of Capricornus. Through a small telescope you can see Neptune just to the north-northwest.
July 15. Last quarter moon is at 5:53 p.m.
July 16. On this day in 1994, the first fragment of Comet Shoemaker-Levy 9 hit Jupiter. After that 20 more mile-wide fragments plowed into Jupiter's gas surface during the next six days, one hitting about every six hours. I watched through a telescope as five of those 21 fragments hit Jupiter, but since they actually hit on the far side of Jupiter, I could not see them until about 30 minutes later as they rotated into view. One of many surprises that these impacts created were the large and easily visible (even in a small telescope) earth-sized black spots that remained visible for many months after the original impacts.
July 21. New moon is at 10:35 p.m.
July 28. First quarter moon is at 6 p.m. and the Delta Aquarid meteor shower peaks.
John Hayes
UFOINFO
Sun, 05 Jul 2009 13:16 UTC
Posted: July 5, 2009
Date: June 6 2009
Time: 11pm
Number of witnesses: 4
Number of objects: 1
Shape of objects: Fireball/bright light
Weather Conditions: Small amount of cloud
Description: A fast moving fireball like object moving in direct path over the A50, seen on two occasions with a full car of people with me. At first we thought it was an aircraft on fire, it almost looked as though the light emitted from the object was passing through and searching the clouds, I dunno. It was moving in a straight line but the light appeared to flicker, but it's path did not falter. Light was not coming from a direct source or visible light or led, like a glowing ball almost.
Date: June 6 2009
Time: 11pm
Number of witnesses: 4
Number of objects: 1
Shape of objects: Fireball/bright light
Weather Conditions: Small amount of cloud
Description: A fast moving fireball like object moving in direct path over the A50, seen on two occasions with a full car of people with me. At first we thought it was an aircraft on fire, it almost looked as though the light emitted from the object was passing through and searching the clouds, I dunno. It was moving in a straight line but the light appeared to flicker, but it's path did not falter. Light was not coming from a direct source or visible light or led, like a glowing ball almost.
John Hayes
UFOINFO
Sun, 05 Jul 2009 14:15 UTC
Posted: July 5, 2009
Date: June 7 2009
Time: 12.20am
Number of witnesses: 1
Number of objects: 1
Shape of objects: Oval orange radiating orange light
Weather Conditions: Dark, with some cloud, but with the moon illuminating the sky behind thin cloud to the left of my field of vision.
Description: I live overlooking a bay, so always have my curtains open. A light in the sky caught my eye as I got up to go to another room. I looked more closely, as I once saw a meteorite entering the atmosphere at around the same point a couple of years ago (although that was in December). This light, however, was luminously orange, and of an oval shape with rays of orange light radiating from it. Its intensity was constant. It hovered, some distance across the bay, and seemed to be still for some moments. I then noticed that when it did move, the movements were purposeful, and not at all random. It moved vertically, horizontally, and diagonally, although slowly without any kind of jerking.
I picked up my phone and tried to take some video footage, but at this point the light faded into the distance. I found your web-site on Google, as I felt I really must tell someone. I've never seen anything like this before.
-----
Hi John
I just wanted to let you know another strange thing that happened from Saturday's incident. I tried to film the UFO on my phone, whilst talking, and was filming for about a minute as the object faded to the left of my field of vision. When I played the film back it had been condensed into 3 seconds, as had my speech. Is this something you have ever heard of before?
Clues to origin of life revealed in Tagish Lake meteorite
New
research into a meteorite that crashed into northern British Columbia
nine years ago is revealing startling clues that could help unravel the
origins of life on Earth.
Parts of the Tagish Lake meteorite were found on a frozen lake near the Yukon border in January, 2000, after it fell to Earth in a spectacular blue-green fireball that was seen for hundreds of kilometres.
Researchers recovered parts of the still-frozen meteorite after an extensive search. Since then, scientists have repeatedly tried to unlock the clues that the rare 4.5 billion-year-old carbon and water rich meteorite has long been suspected to contain.
Now, a team at the University of Alberta has found some important material nestled inside the rock, formic acid - the key ingredient in bee stings, ant venom and stinging nettles.
U of A scientist Chris Herd says similar molecules on much, much earlier meteorites may have been instrumental in kick-starting life on Earth, making the meteorite the most important rock ever found on Earth.
"Four billion years ago, when the Earth had kind of cooled off from its initial hot state, and there was liquid water on the surface, we may have had an influx of meteorites like Tagish Lake [that] delivered the right mix of molecules to the Earth's surface," he said.
How exactly that mix might have turned into actual life is still a mystery, but Herd said the findings of formic acid on the meteorite may provide important clues.
"It's a type of molecule known as a carboxylic acid. So it's sort of like the shortest, smallest molecule in that group. The longer molecules in this same group are actually what life uses in building cell walls."
In 2001, U.S. exobiologist Sandra Pizzarello, who was studying some of the fragments from the Tagish meteorite at Arizona State University, said they contained almost no amino acids but did contain high concentrations of hydrocarbon molecules, along with a type of clay that forms in the presence of water.
In 2006, Mike Zolensky, a cosmic mineralogist at the NASA Space Centre in Texas, said tiny bubbles in the rock were organic globules where the universe's earliest life forms could have been able to live.
A
number of viewers throughout the Susquehanna Valley have contacted News
8 about a bright light they saw in the night sky, and an explosion they
heard and felt early Monday morning.
"At approx. 1:05 a.m. my wife and I were outside enjoying the cool evening and we saw a bright flash of light and a few seconds later we heard a series of explosions. Do you have any information on that?" read one.
"I just wanted to report something very strange. At about 1:10 AM while laying in bed. We heard and felt a deep rumble, the house shook and we felt either an explosion shock wave or an earth quake," read another.
News 8 has been looking into the reports and contacted a member of the American Meteor Society, Robert Lunsford, who said it was likely a "fireball," a brighter than normal meteor. Lunsford also said it was likely larger than a normal meteor.
"I now have 15 reports of this object," he said. "It is most certainly a fireball, one that survived low enough to have produced a sonic boom and produce possible fragments on the ground (meteorites) near its end point."
Lunsford said he received reports from Pennsylvania, New York, New Jersey, and Maryland. No confirmed impact site has yet been found, according to Lunsford.
People in our u local forum have said they saw the fireball in Adams County, Lancaster County, Lebanon County, York County, and even in Chester County. Some say it lit the whole night sky. You can read those reports here.
We
have been receiving reports today of a likely meteor over north-central
Maryland and southern Pennsylvania early Monday morning. (Not the one
in the Flickr.com image seen here.)
Below are the first reports we have received. If you heard or saw something similar, around the same time, please leave a comment. Include the time, your location, which direction you saw the object or flash, a description of what you saw, and note any boom or other sound you heard, as well as the time lapse between flash and boom.
The York Dispatch: In York County, Pa., police officers from Penn Township, Southwestern Regional and Newberry Township reported seeing a flash and hearing a boom around 1:15 a.m. Monday, July 6, according to local 911 centers. Officials in Harford County, Md. also reported seeing a flash and hearing a boom near the Mason-Dixon Line.
Capital Gazette: An Annapolis city police officer reported that she and her partner both saw what she described as a "bright blue light in the sky" just after midnight. It was followed by "a light with a tail, falling from the sky," according to our informant. Annapolis police reported hearing a similar report on Baltimore County police radio.
Gary Moon, reporting to The Sun's News Tips: "I heard and felt a deep earth blast similar to an earthquake, which shook my home in Glen Rock, Pa., early Monday morning. I thought I would hear MUCH more about this one ... nothing."
Deborah Markow, Havre de Grace: "Last night, couldn't sleep, went out on back deck, laid on lounge, eyes closed and then it was like someone pointed a flash light in my eyes it was so bright. I saw another one streak through the sky ... It was one of the most thrilling sights to behold a ball of fire flying through the sky."
I have not yet seen any meteor reports of this event on the American Meteor Society's Fireball Sightings Log, but it's early yet, and this fireball, coming in the wee hours after a long holiday, probably did not catch many people out and about.
Which makes reports like these, and yours, all the more important. If you saw this object, be sure to leave a report with the AMS, too.
But judging from the descriptions, it almost certainly was a fireball, which is simply an especially bright meteor, vaporizing with an impressive flash.
Here's a pretty good example on video.
They are sometimes followed by a sonic boom, which would explain the booming noises in the reports. Some fireball observers - though none yet for this event - also report a crackling or hissing sound that is concurrent with the meteor's flash and which has never been fully explained scientifically.
Although meteor rates begin to pick up in July, this is not the peak time for any particular meteor shower. It seems likely this was a "sporadic," or isolated meteor that just happened to be especially big and bright. Big ones like this are always unexpected, always startling to witness, and always a thrill.
Date: June 7 2009
Time: 12.20am
Number of witnesses: 1
Number of objects: 1
Shape of objects: Oval orange radiating orange light
Weather Conditions: Dark, with some cloud, but with the moon illuminating the sky behind thin cloud to the left of my field of vision.
Description: I live overlooking a bay, so always have my curtains open. A light in the sky caught my eye as I got up to go to another room. I looked more closely, as I once saw a meteorite entering the atmosphere at around the same point a couple of years ago (although that was in December). This light, however, was luminously orange, and of an oval shape with rays of orange light radiating from it. Its intensity was constant. It hovered, some distance across the bay, and seemed to be still for some moments. I then noticed that when it did move, the movements were purposeful, and not at all random. It moved vertically, horizontally, and diagonally, although slowly without any kind of jerking.
I picked up my phone and tried to take some video footage, but at this point the light faded into the distance. I found your web-site on Google, as I felt I really must tell someone. I've never seen anything like this before.
-----
Hi John
I just wanted to let you know another strange thing that happened from Saturday's incident. I tried to film the UFO on my phone, whilst talking, and was filming for about a minute as the object faded to the left of my field of vision. When I played the film back it had been condensed into 3 seconds, as had my speech. Is this something you have ever heard of before?
Clues to origin of life revealed in Tagish Lake meteorite
CBC News
Sun, 05 Jul 2009 06:45 UTC
© Photo by P.A. Hunt, Geological Survey of Canada, Natural Resources Canada.
Photo 2:Photomicrograph in crossed polars of a portion of a polished thin section of the Tagish Lake Meteorite. The bright areas A-E are preserved high temperature silicate (olivine, pyroxene) 'chondrules' in a dark matrix of clay, serpentine, magnetite, sulphide, carbonate and phosphate etc. Object 'D' is approximately 0.3mm across.
Photo 2:Photomicrograph in crossed polars of a portion of a polished thin section of the Tagish Lake Meteorite. The bright areas A-E are preserved high temperature silicate (olivine, pyroxene) 'chondrules' in a dark matrix of clay, serpentine, magnetite, sulphide, carbonate and phosphate etc. Object 'D' is approximately 0.3mm across.
Parts of the Tagish Lake meteorite were found on a frozen lake near the Yukon border in January, 2000, after it fell to Earth in a spectacular blue-green fireball that was seen for hundreds of kilometres.
Researchers recovered parts of the still-frozen meteorite after an extensive search. Since then, scientists have repeatedly tried to unlock the clues that the rare 4.5 billion-year-old carbon and water rich meteorite has long been suspected to contain.
Now, a team at the University of Alberta has found some important material nestled inside the rock, formic acid - the key ingredient in bee stings, ant venom and stinging nettles.
U of A scientist Chris Herd says similar molecules on much, much earlier meteorites may have been instrumental in kick-starting life on Earth, making the meteorite the most important rock ever found on Earth.
"Four billion years ago, when the Earth had kind of cooled off from its initial hot state, and there was liquid water on the surface, we may have had an influx of meteorites like Tagish Lake [that] delivered the right mix of molecules to the Earth's surface," he said.
How exactly that mix might have turned into actual life is still a mystery, but Herd said the findings of formic acid on the meteorite may provide important clues.
"It's a type of molecule known as a carboxylic acid. So it's sort of like the shortest, smallest molecule in that group. The longer molecules in this same group are actually what life uses in building cell walls."
In 2001, U.S. exobiologist Sandra Pizzarello, who was studying some of the fragments from the Tagish meteorite at Arizona State University, said they contained almost no amino acids but did contain high concentrations of hydrocarbon molecules, along with a type of clay that forms in the presence of water.
In 2006, Mike Zolensky, a cosmic mineralogist at the NASA Space Centre in Texas, said tiny bubbles in the rock were organic globules where the universe's earliest life forms could have been able to live.
WGAL.com
Mon, 06 Jul 2009 07:42 UTC
"At approx. 1:05 a.m. my wife and I were outside enjoying the cool evening and we saw a bright flash of light and a few seconds later we heard a series of explosions. Do you have any information on that?" read one.
"I just wanted to report something very strange. At about 1:10 AM while laying in bed. We heard and felt a deep rumble, the house shook and we felt either an explosion shock wave or an earth quake," read another.
News 8 has been looking into the reports and contacted a member of the American Meteor Society, Robert Lunsford, who said it was likely a "fireball," a brighter than normal meteor. Lunsford also said it was likely larger than a normal meteor.
"I now have 15 reports of this object," he said. "It is most certainly a fireball, one that survived low enough to have produced a sonic boom and produce possible fragments on the ground (meteorites) near its end point."
Lunsford said he received reports from Pennsylvania, New York, New Jersey, and Maryland. No confirmed impact site has yet been found, according to Lunsford.
People in our u local forum have said they saw the fireball in Adams County, Lancaster County, Lebanon County, York County, and even in Chester County. Some say it lit the whole night sky. You can read those reports here.
Frank Roylance
The Baltimore Sun
Mon, 06 Jul 2009 07:44 UTC
© flickr.com
Below are the first reports we have received. If you heard or saw something similar, around the same time, please leave a comment. Include the time, your location, which direction you saw the object or flash, a description of what you saw, and note any boom or other sound you heard, as well as the time lapse between flash and boom.
The York Dispatch: In York County, Pa., police officers from Penn Township, Southwestern Regional and Newberry Township reported seeing a flash and hearing a boom around 1:15 a.m. Monday, July 6, according to local 911 centers. Officials in Harford County, Md. also reported seeing a flash and hearing a boom near the Mason-Dixon Line.
Capital Gazette: An Annapolis city police officer reported that she and her partner both saw what she described as a "bright blue light in the sky" just after midnight. It was followed by "a light with a tail, falling from the sky," according to our informant. Annapolis police reported hearing a similar report on Baltimore County police radio.
Gary Moon, reporting to The Sun's News Tips: "I heard and felt a deep earth blast similar to an earthquake, which shook my home in Glen Rock, Pa., early Monday morning. I thought I would hear MUCH more about this one ... nothing."
Deborah Markow, Havre de Grace: "Last night, couldn't sleep, went out on back deck, laid on lounge, eyes closed and then it was like someone pointed a flash light in my eyes it was so bright. I saw another one streak through the sky ... It was one of the most thrilling sights to behold a ball of fire flying through the sky."
I have not yet seen any meteor reports of this event on the American Meteor Society's Fireball Sightings Log, but it's early yet, and this fireball, coming in the wee hours after a long holiday, probably did not catch many people out and about.
Which makes reports like these, and yours, all the more important. If you saw this object, be sure to leave a report with the AMS, too.
But judging from the descriptions, it almost certainly was a fireball, which is simply an especially bright meteor, vaporizing with an impressive flash.
Here's a pretty good example on video.
They are sometimes followed by a sonic boom, which would explain the booming noises in the reports. Some fireball observers - though none yet for this event - also report a crackling or hissing sound that is concurrent with the meteor's flash and which has never been fully explained scientifically.
Although meteor rates begin to pick up in July, this is not the peak time for any particular meteor shower. It seems likely this was a "sporadic," or isolated meteor that just happened to be especially big and bright. Big ones like this are always unexpected, always startling to witness, and always a thrill.
UK UFO Sighting Reports
Thu, 09 Jul 2009 14:38 UTC
Date of Sighting: Saturday 4th July 2009
Time: 10:50pm
Witness Statement: We were watching the tv on Saturday the 4th July 2009 when at 10.50pm we had a loud knock on the door. It was our neighbour who said to come and have a look at the sky. When we looked there was an orange glow, almost like a flame arcing across the sky from West to East, at some speed but with no noise. As this disappeared, another one would appear, in total 14, had been seen by our neighbour, then later one was seen going South to North exactly the same. This was over Great Sankey, Warrington. I took a video on my camera, but not very good quality.
Jane Holahan
Lancaster Online
Fri, 10 Jul 2009 15:28 UTC
If you saw a bright flash of light in the sky about 1 a.m. Monday, it wasn't a leftover firework. It was a meteor.
And a pretty impressive one at that.
Michael Gaines, who lives near the Costco on Hempstead Road, had gotten home from the Long's Park Patriotic Concert a few hours earlier and saw the flash from his porch.
With an interest in astronomy, Gaines knew that it wasn't a stray Fourth of July sparkler.
"It was a lot brighter than fireworks," said Gaines, who realized he was seeing the fireball of a large meteor. "You could see remnants, little fragments - something was moving from right to left across the sky."
Mike Smith of the North Museum, who writes the Cosmic Mike column for this newspaper, said Gaines was not alone in spotting the sky show.
"There have been many reports of people sighting what can be called a fireball, a large (meteor)," he said.
According to a story in the Baltimore Sun, geologists said that the object would have to be a few yards in diameter to have attracted the attention it did.
Based on witness descriptions, the object appeared at approximately 1:05 a.m. and flew south to north over central Maryland and southern Pennsylvania before vaporizing at 1:10 a.m.
One man, camping on the Susquehanna River in Delta, wrote on the Baltimore Sun's weather blog: "It was as if it were daylight outside. ... Approximately 60 to 90 seconds after the sky had lit up, we heard a thunderous series of sonic boom sounds accompanied by tremors."
Gaines, along with a number of other people in Pennsylvania and Maryland, recorded what they saw on the Web site amsmeteors.org.
"For Lancastrians to be able to see a fireball, I'd say that's rare," Smith said. "The majority are really small and burn up before they touch surface."
Meteors, which become meteorites once they hit the ground, are leftover debris from comets and are scattered along the comet's orbit around the sun.
Some meteor showers are predictable. For example, the Perseids peaks in mid-August every year. Others, like the one spotted Monday, are a surprise.
"Quite a few reports say it came down somewhere, but I don't know if they'll find it," Gaines said. "That's a lot of land to cover for something that was probably the size of a fist when it landed."
Intelligencer Journal/Lancaster New Era
"Meteorite
Man" Steve Arnold is still looking for those key eyewitness reports
that could point him toward any remnants of the July 6 Mason-Dixon
Meteor that may have survived the fall to Earth.
Arnold has read through more than 100 comments from Weather Blog readers who saw or heard the meteor, and he's singled out more than 30 that were detailed enough to suggest that just a little more information might help point him to the impact zone.
That's Arnold below on Wednesday, kneeling in front of the Water Co. security apparatus that captured video of the meteor as it fell east of York, Pa. Monday morning. (Click here to see the video.)
The
camera itself is the dark gray object attached to the bottom of the
silver box. The videographer at right is TV producer Bob Melisso, who
is filming Arnold's search on behalf of the Science Channel program
"Meteorite Men."
Here's what he's asking for. And below his note are the names of the commenters he wants to hear from.
For those of you that saw the fireball, please reply with the following details:
The WeatherBlog commenters he'd like to hear from are:
Siobhan, in West Chester, Pa.; M Gaines, in Lancaster, Pa.; Matt B, in Bel Air; Melissa Tillery, who was driving on I-70 near Hagerstown; Sam Luther, who was camping near Delta, Pa.; John, in rural northwest Harford, Co.; Diane, in Port Deposit; Chuck and Nikki, in Port Deposit;
Raquel, in Bergen County, N.J.; Nicole Green, in Pikesville; Myranda Warfield, in Jefferson; Mike and Julie, in Forest Hill; DJ, in Bel Air; Kimberly, in Forest Hill; DCD, in Littlestown, Pa.; Lisa Ewing, in Port Deposit; Karen Haney, in Hickory, north of Bel Air; Jenny Gresock, in Seven Valleys, Pa.;
Frank Memmo, in Churchville; Ashley Simpson, in Arnold; Chris, in Conowingo area of Cecil County; Kristen B., in Forest Hill; Dale, in Forest Hill; Tom D., who was southbound on I-83 in York, Pa.; Matt Bureau, in Greensburg, Pa.; Timothy Jones, in Philadelphia;
Chelsea, in Forest Hill; Terry, in Earlesville; Sue, in White Marsh; and HC, who was southbound on I-83 near Glen Rock, Pa.
Thanks. We'll keep you posted on any progress in the meteorite hunt.
And while we're on the topic, NBC on Sunday night will air yet another movie about a meteor headed for the Earth, and beautiful scientists racing to save the planet. It's called, "Meteor," of all things, and it starts at 9 p.m. on WBAL Channel 11 in Baltimore.
Jason Alexander ("Seinfeld's" George Castanza) is among the cast.
Come back here after it's over and let's see how many scientific errors we can list.
Date of Sighting: 12th July 2009
Time: 10.14pm
Witness Statement: I popped out to the back garden for a cigarette and there was a large object in the sky traveling very fast. It looked like a ball of fire and was traveling approx 3 x the speed of an aeroplane. I called my girlfriend who came out and also saw it. She thought it was an aeroplane on fire! I asked her to run and get the camera but she took ages, I watched it move along the sky until it was completely out of sight. Considering how bright it was and how clearly I could see it, it must have been really moving! There was not a cloud in the sky, I have seen many planes and helicopters and this was definitely something I have not seen before!! Did anyone else see this or has anyone got an explanation??
And a pretty impressive one at that.
Michael Gaines, who lives near the Costco on Hempstead Road, had gotten home from the Long's Park Patriotic Concert a few hours earlier and saw the flash from his porch.
With an interest in astronomy, Gaines knew that it wasn't a stray Fourth of July sparkler.
"It was a lot brighter than fireworks," said Gaines, who realized he was seeing the fireball of a large meteor. "You could see remnants, little fragments - something was moving from right to left across the sky."
Mike Smith of the North Museum, who writes the Cosmic Mike column for this newspaper, said Gaines was not alone in spotting the sky show.
"There have been many reports of people sighting what can be called a fireball, a large (meteor)," he said.
According to a story in the Baltimore Sun, geologists said that the object would have to be a few yards in diameter to have attracted the attention it did.
Based on witness descriptions, the object appeared at approximately 1:05 a.m. and flew south to north over central Maryland and southern Pennsylvania before vaporizing at 1:10 a.m.
One man, camping on the Susquehanna River in Delta, wrote on the Baltimore Sun's weather blog: "It was as if it were daylight outside. ... Approximately 60 to 90 seconds after the sky had lit up, we heard a thunderous series of sonic boom sounds accompanied by tremors."
Gaines, along with a number of other people in Pennsylvania and Maryland, recorded what they saw on the Web site amsmeteors.org.
"For Lancastrians to be able to see a fireball, I'd say that's rare," Smith said. "The majority are really small and burn up before they touch surface."
Meteors, which become meteorites once they hit the ground, are leftover debris from comets and are scattered along the comet's orbit around the sun.
Some meteor showers are predictable. For example, the Perseids peaks in mid-August every year. Others, like the one spotted Monday, are a surprise.
"Quite a few reports say it came down somewhere, but I don't know if they'll find it," Gaines said. "That's a lot of land to cover for something that was probably the size of a fist when it landed."
Intelligencer Journal/Lancaster New Era
Frank D. Roylance
weblogs.marylandweather.com
Sun, 12 Jul 2009 08:08 UTC
© baltimoresun.com
The big fireball meteor that startled residents in Central Maryland and southern Pennsylvania early Monday morning was captured on a security camera video in York Pa.
The big fireball meteor that startled residents in Central Maryland and southern Pennsylvania early Monday morning was captured on a security camera video in York Pa.
Arnold has read through more than 100 comments from Weather Blog readers who saw or heard the meteor, and he's singled out more than 30 that were detailed enough to suggest that just a little more information might help point him to the impact zone.
That's Arnold below on Wednesday, kneeling in front of the Water Co. security apparatus that captured video of the meteor as it fell east of York, Pa. Monday morning. (Click here to see the video.)
© baltimoresun.com / Frank D. Roylance
Steve Arnold kneeling in front of the Water Co. security apparatus that captured video of the meteor
Steve Arnold kneeling in front of the Water Co. security apparatus that captured video of the meteor
Here's what he's asking for. And below his note are the names of the commenters he wants to hear from.
For those of you that saw the fireball, please reply with the following details:
- The address (including city and zip code) where you saw it?
- What direction you were facing when seeing it?
- If you were indoors, and saw it through a window, what direction the window was facing?
- What direction the fireball appeared to be heading from your perspective?
- If you saw the fireball burn out, could you pinpoint exactly (or close to) the direction it extinguished?
- Was there a landmark between you and the fireball that helped you positively pinpoint the direction it was from you when it quit burning?
- If you heard a sonic boom, how long was it between seeing the light and hearing the sonic boom. What other details that are relevant.
The WeatherBlog commenters he'd like to hear from are:
Siobhan, in West Chester, Pa.; M Gaines, in Lancaster, Pa.; Matt B, in Bel Air; Melissa Tillery, who was driving on I-70 near Hagerstown; Sam Luther, who was camping near Delta, Pa.; John, in rural northwest Harford, Co.; Diane, in Port Deposit; Chuck and Nikki, in Port Deposit;
Raquel, in Bergen County, N.J.; Nicole Green, in Pikesville; Myranda Warfield, in Jefferson; Mike and Julie, in Forest Hill; DJ, in Bel Air; Kimberly, in Forest Hill; DCD, in Littlestown, Pa.; Lisa Ewing, in Port Deposit; Karen Haney, in Hickory, north of Bel Air; Jenny Gresock, in Seven Valleys, Pa.;
Frank Memmo, in Churchville; Ashley Simpson, in Arnold; Chris, in Conowingo area of Cecil County; Kristen B., in Forest Hill; Dale, in Forest Hill; Tom D., who was southbound on I-83 in York, Pa.; Matt Bureau, in Greensburg, Pa.; Timothy Jones, in Philadelphia;
Chelsea, in Forest Hill; Terry, in Earlesville; Sue, in White Marsh; and HC, who was southbound on I-83 near Glen Rock, Pa.
Thanks. We'll keep you posted on any progress in the meteorite hunt.
And while we're on the topic, NBC on Sunday night will air yet another movie about a meteor headed for the Earth, and beautiful scientists racing to save the planet. It's called, "Meteor," of all things, and it starts at 9 p.m. on WBAL Channel 11 in Baltimore.
Jason Alexander ("Seinfeld's" George Castanza) is among the cast.
Come back here after it's over and let's see how many scientific errors we can list.
UK UFO Sighting Reports
Mon, 13 Jul 2009 17:03 UTC
Date of Sighting: 12th July 2009
Time: 10.14pm
Witness Statement: I popped out to the back garden for a cigarette and there was a large object in the sky traveling very fast. It looked like a ball of fire and was traveling approx 3 x the speed of an aeroplane. I called my girlfriend who came out and also saw it. She thought it was an aeroplane on fire! I asked her to run and get the camera but she took ages, I watched it move along the sky until it was completely out of sight. Considering how bright it was and how clearly I could see it, it must have been really moving! There was not a cloud in the sky, I have seen many planes and helicopters and this was definitely something I have not seen before!! Did anyone else see this or has anyone got an explanation??
Rachel Courtland
New Scientist
Wed, 15 Jul 2009 04:28 UTC
Millions of objects in the solar system's main asteroid belt may be icy
interlopers from beyond Neptune that were flung into their present
orbits after a violent migration of the giant planets, a new simulation
suggests.
The
solar system's main asteroid belt is a diverse mix of objects that
orbit between Mars and Jupiter. These asteroids are generally thought
to have formed close to their present locations, so their compositions
should reflect the original distribution of gas and dust that
surrounded the sun there and eventually condensed into solid bodies.
"People have just been assuming that what we see there, formed there," says Hal Levison of the Southwest Research Institute in Boulder, Colorado.
But Levison and others suspect some 20 per cent of the asteroids in the belt may be comet-like objects that were born in colder climes, beyond the orbit of Neptune.
Scattered objects
The results come from new simulations using a theory called the Nice model, which suggests the solar system's giant planets were born closer together and were surrounded by a vast disc of leftovers from the planets' formation called planetesimals (see here).
According to the model, Jupiter and Saturn entered a tight orbital dance about 700 million years after the solar system formed. Their gravity then flung Uranus and Neptune out into the planetesimal disc like bowling balls, causing the objects there to scatter like pins.
Past simulations have tracked the trajectories of these planetesimals and showed they wind up forming the Kuiper belt of icy debris where Pluto sits, some of the distant satellites of Jupiter and Saturn, and Trojan asteroids, bodies that share Jupiter's orbit but are centred at two points ahead of and behind the planet.
Outer belt
The new simulation fed planetesimals into the region surrounding Jupiter and Saturn as the planets moved to see how many would be captured as so-called Hilda asteroids, a group outside the main asteroid belt that orbits the sun three times for each two orbits of Jupiter.
While some of the objects became Hildas and Trojans, most of the captured objects wound up in the outer portion of the solar system's main asteroid belt.
Indeed, the outer asteroid belt boasts objects that are thought to have ice, while the inner asteroid belt is dominated by rocky bodies. "The interpretation has been that this represents a change in the nebula or the disc from which the planets formed," Levison told New Scientist.
Partial simulation
But if these icy outer objects are newcomers, it would mean that objects in the asteroid belt did not all form close to their present locations. "It says to the community that the assumptions you've been making don't necessarily have to be true," Levison says.
But Renu Malhotra of the University of Arizona in Tucson says she's not convinced of the estimate that 20 per cent of the asteroids in the main belt could come from the outer solar system.
That's because the new study didn't simulate the process that knocked the planetesimals out of their original orbits - it only sent objects from the outer solar system inwards to find out what fraction would be captured.
"It's not clear how statistically probable this is," Malhotra says. The simplest hypothesis, she adds, is that most of the asteroids in the main belt are original residents.
Journal reference: Nature (vol 460, p 364)
Many of the primitive bodies
wandering the asteroid belt between Mars and Jupiter are former comets,
tossed out of orbit by a brutal ballet between the giant outer planets,
say a team of astrophysicists.
A commonly accepted theory is that the asteroid belt is the rubble left over from a "proto-planetary disk," the dense ring of gas that surrounds a new-born star.
But the orbiting rocks have long been a source of deep curiosity. They are remarkably varied, ranging from mixtures of ice and rock to igneous rocks, which implies they have jumbled origins.
The answer to the mystery, according to a study published by the British journal Nature on Wednesday, is that a "significant fraction" of the asteroid population in fact comprises ex-comets.
Famously described as "dirty snowballs" of ice and dust, comets are lonely, long-distance wanderers of the Solar System whose elliptical swing around the Sun can take decades.
Researchers in France and the United States ran a mathematical model of the development of the early Solar System, when the planets were accreting from clustering masses of dust and gas.
According to this model, the nascent giant planets -- Jupiter, Saturn, Uranus and Neptune -- orbited at this time in a pretty compact configuration, between five and 15 astronomical units (AUs) from the Sun.
An AU is a standard unit of measurement for Solar System distances. It equals the distance from the Earth to the Sun, or around 150 million kilometres (93 million miles).
Beyond the giant planets was a disk-shaped mass of comets, known as trans-Neptunian objects, between 16 and 30 AUs from the Sun.
As the giants became bigger and bigger, their orbits became unstable.
Eventually, after around 600 million years, Uranus and Neptune were kicked out by gravitational jousting.
They rammed into the disk of comets and scattered its members throughout the Solar System, according to this model. Many of them were captured by the weak gravitational force of the asteroid belt, where they remain to this day.
"It's a paradigm shift," said Matthieu Gounelle of France's National Centre for Scientific Research (CNRS) in a press release.
"The asteroid belt is not just a leftover from the formation of the Solar System, but also that of violent phenomena" including the great planetary migration.
If the model is right, it implies that the difference between the most primitive asteroids and comets is even slimmer than thought.
It would also shed light on the controversial origin of micrometeorites, or tiny extraterrestrial particles that survive the fiery passage through Earth's atmosphere.
Micrometeorites are different from meteorites in composition and texture, and this could be explained if they derive from comets, which are richer in organic material and crumblier than native asteroids.
Many
of the objects found today in the asteroid belt located between the
orbits of Mars and Jupiter may have formed in the outermost reaches of
the solar system, according to an international team of astronomers led
by scientists from Southwest Research Institute (SwRI).
The team used numerical simulations to show that some comet-like objects residing in a disk outside the original orbit of the planets were scattered across the solar system and into the outer asteroid belt during a violent phase of planetary evolution.
Usually, the solar system is considered a place of relative permanence, with changes occurring gradually over hundreds of millions to billions of years. New models of planet formation indicate, however, that at specific times, the architecture of the solar system experienced dramatic upheaval.
In particular, it now seems probable that approximately 3.9 billion years ago, the giant planets of our solar system -- Jupiter, Saturn, Uranus and Neptune -- rearranged themselves in a tumultuous spasm. "This last major event of planet formation appears to have affected nearly every nook and cranny of the solar system," says lead author Dr. Hal Levison of SwRI.
Key evidence for this event was first identified in the samples returned from the Moon by the Apollo astronauts. They tell us about an ancient cataclysmic bombardment where large asteroids and comets rained down on the Moon.
Scientists now recognize that this event was not limited solely to the Moon; it also affected the Earth and many other solar system bodies. "The existence of life on Earth, as well as the conditions that made our world habitable for us, are strongly linked to what happened at this distant time," states Dr. David Nesvorny of SwRI.
The same dynamical conditions that devastated the planets also led to the capture of some would-be impactors in the asteroid belt. "In the classic movie Casablanca, everybody comes to Rick's. Apparently throughout the solar system, the cool hangout for small objects is the asteroid belt," says Dr. William Bottke of SwRI.
Once in the asteroid belt, the embedded comet-like objects began to beat up both themselves and the asteroids. "Our model shows that comets are relatively easy to break up when hit by something, at least when compared to typical asteroids. It is unavoidable that some of the debris went on to land on asteroids, the Moon and the Earth. In fact, some of the leftovers may still be arriving today," says Dr. Alessandro Morbidelli of the Observatoire de la Cote d'Azur in Nice, France.
The team believes the surprising similarities between some micrometeorites landing on Earth and comet samples returned by NASA's Stardust mission are no accident. "There has been lots of debate about the nature of micrometeorites reaching the Earth," says Dr. Matthieu Gounelle of the Museum National d'Histoire Naturelle in Paris. "Some believe they are asteroidal, while others argue they are cometary. Our work suggests that in a sense, both camps may be right."
"Some of the meteorites that once resided in the asteroid belt show signs they were hit by 3.5 to 3.9 billion years ago. Our model allows us to make the case they were hit by captured comets or perhaps their fragments," adds Dr. Kleomenis Tsiganis of Aristotle University of Thessaloniki, Greece. "If so, they are telling us the same intriguing story as the lunar samples, namely that the solar system apparently went berserk and reconfigured itself about 4 billion years ago."
Overall, the main asteroid belt contains a surprising diversity of objects ranging from primitive ice/rock mixtures to igneous rocks. The standard model used to explain this assumes that most asteroids formed in place from a primordial disk that experienced radical chemical changes within this zone. This model shows, however, that the observed diversity of the asteroid belt is not a direct reflection of the intrinsic compositional variation of the proto-planetary disk. These results fundamentally change our view of the asteroid belt.
Additional tests of this model will come from studies of meteorites, the asteroid belt, planet formation and the Moon. "The Moon and the asteroid belt may be the best and most accessible places in the solar system to understand this critical part of solar system history," says Levison. "We believe key evidence from these cold airless bodies may help us unlock the biggest 'cold case' of all time."
Funding for this research was provided by NASA's Outer Planets Research and Origins of Solar Systems programs. Additional support was provided by NASA's Lunar Science Institute.
Journal reference:
1. Levison et al. Contamination of the asteroid belt by primordial trans-Neptunian objects. Nature, 2009; 460 (7253): 364 DOI: 10.1038/nature08094
Did
something just hit Jupiter? On July 19th, a black "scar" appeared in
Jupiter's clouds similar to the Shoemaker-Levy 9 impacts of 1994.
Veteran Jupiter observer Anthony Wesley photographed the feature from
his observatory in Murrumbateman, Australia.
"The jet-black mark is near Jupiter's south pole (south is up in the image)," says Wesley. "I have imagery of that same location from two nights earlier without the impact mark, so this is a very recent event. The material has already begun to spread out in a fan shape on one side, and should be rapidly pulled apart by the fast jetstream winds. I recorded a lot of footage, and will be generating more images and a rotation animation soon."
Amateur astronomers around the world should train their telescopes on Jupiter tonight to monitor the progress of this possible impact event: sky map. Stay tuned for more images and updates.
A
17-member team has found what may be the smoking gun of a much-debated
proposal that a cosmic impact about 12,900 years ago ripped through
North America and drove multiple species into extinction.
In a paper appearing online ahead of regular publication in the Proceedings of the National Academy of Sciences, University of Oregon archaeologist Douglas J. Kennett and colleagues from nine institutions and three private research companies report the presence of shock-synthesized hexagonal diamonds in 12,900-year-old sediments on the Northern Channel Islands off the southern California coast.
These tiny diamonds and diamond clusters were buried deeply below four meters of sediment. They date to the end of Clovis -- a Paleoindian culture long thought to be North America's first human inhabitants. The nano-sized diamonds were pulled from Arlington Canyon on the island of Santa Rosa that had once been joined with three other Northern Channel Islands in a landmass known as Santarosae.
The diamonds were found in association with soot, which forms in extremely hot fires, and they suggest associated regional wildfires, based on nearby environmental records.
Such soot and diamonds are rare in the geological record. They were found in sediment dating to massive asteroid impacts 65 million years ago in a layer widely known as the K-T Boundary. The thin layer of iridium-and-quartz-rich sediment dates to the transition of the Cretaceous and Tertiary periods, which mark the end of the Mesozoic Era and the beginning of the Cenozoic Era.
"The type of diamond we have found -- Lonsdaleite -- is a shock-synthesized mineral defined by its hexagonal crystalline structure. It forms under very high temperatures and pressures consistent with a cosmic impact," Kennett said. "These diamonds have only been found thus far in meteorites and impact craters on Earth and appear to be the strongest indicator yet of a significant cosmic impact [during Clovis]."
The
age of this event also matches the extinction of the pygmy mammoth on
the Northern Channel Islands, as well as numerous other North American
mammals, including the horse, which Europeans later reintroduced. In
all, an estimated 35 mammal and 19 bird genera became extinct near the
end of the Pleistocene with some of them occurring very close in time
to the proposed cosmic impact, first reported in October 2007 in PNAS.
In the Jan. 2, 2009, issue of the journal Science, a team led by Kennett reported the discovery of billions of nanometer-sized diamonds concentrated in sediments -- weighing from about 10 to 2,700 parts per billion -- in six North American locations.
"This site, this layer with hexagonal diamonds, is also associated with other types of diamonds and with dramatic environmental changes and wildfires," said James Kennett, paleoceanographer and professor emeritus in the Department of Earth Science at the University of California, Santa Barbara.
"There was a major event 12,900 years ago," he said. "It is hard to explain this assemblage of materials without a cosmic impact event and associated extensive wildfires. This hypothesis fits with the abrupt cooling of the atmosphere as shown in the record of ocean drilling of the Santa Barbara Channel. The cooling resulted when dust from the high-pressure, high-temperature, multiple impacts was lofted into the atmosphere, causing a dramatic drop in solar radiation."
The hexagonal diamonds from Arlington Canyon were analyzed at the UO's Lorry I. Lokey Laboratories, a world-class nanotechnology facility built deep in bedrock to allow for sensitive microscopy and other high-tech analyses of materials. The analyses were done in collaboration with FEI, a Hillsboro, Ore., company that distributes the high-resolution Titan microscope used to characterize the hexagonal diamonds in this study.
Transmission electron microscopy and scanning electron microscopes were used in the extensive analyses of the sediment that contained clusters of Lonsdaleite ranging in size from 20 to 1,800 nanometers. These diamonds were inside or attached to carbon particles found in the sediments.
These findings are inconsistent with the alternative and already hotly debated theory that overhunting by Clovis people led to the rapid extinction of large mammals at the end of the ice age, the research team argues in the PNAS paper. An alternative theory has held that climate change was to blame for these mass extinctions. The cosmic-event theory suggests that rapid climate change at this time was possibly triggered by a series of small and widely dispersed comet strikes across much of North America.
An
amateur Australian astronomer has set the space-watching world on fire
after discovering that a rare comet or asteroid had crashed into
Jupiter, leaving an impact the size of Earth.
Anthony Wesley, 44, a computer programmer from Murrumbateman, a village north of Canberra, made the discovery about 1am yesterday using his backyard 14.5-inch reflecting telescope.
The impact would have occurred no more than two days earlier and will only be visible for another few days.
Within hours, his images had spread across the internet on science websites.
NASA's Jet Propulsion Laboratory confirmed the discovery at 9pm yesterday using its large infrared telescope at the summit of Mauna Kea in Hawaii.
The only other time astronomers have discovered evidence of a space object having hit Jupiter was when the Shoemaker-Levy 9 comet collided with the giant planet in July, 1994.
That event was also the first direct observation of two objects colliding in space.
Glenn Orton, the NASA scientist who confirmed Wesley's discovery, said: "We are extremely lucky to be seeing Jupiter at exactly the right time, the right hour, the right side of Jupiter to witness the event. We couldn't have planned it better."
Orton said he was not yet sure whether the object that hit Jupiter was a comet, asteroid or some other piece of space junk. But the impact mark is about the size of the Earth.
"It's been a whirlwind of a day and this, on the anniversary of the Shoemaker-Levy 9 and Apollo anniversaries, is amazing," he said.
To most people the image is unremarkable and appears as little more than a scar on Jupiter's vast gas surface.
Leigh Fletcher, an astronomer who worked with Orton on confirming the discovery last night, said: "These are the most exciting observations I've seen in my five years of observing the outer planets."
Wesley said in a phone interview that documenting these sorts of impacts was the only way to get new data on how the solar system formed and what planets such as Jupiter are made of, as the impact throws up debris that would otherwise be invisible when looking through a telescope from Earth.
The collision also allows astronomers to examine Jupiter's role in cleaning up space debris in the solar system.
"If anything like that had hit the Earth it would have been curtains for us, so we can feel very happy that Jupiter is doing its vacuum-cleaner job and hoovering up all these large pieces before they come for us," he said.
"An impact event like this, even just knowing how often they happen, gives you some idea of how much debris is left over from the solar system when it formed and how quickly Jupiter is vacuuming up the remains of the bits and pieces floating around in the solar system."
Mike Salway, who runs the Australian amateur astronomy community website iceinspace.com.au, said astronomers around the world were raving about the discovery.
"Amateur astronomers are all over it at the moment - they all had their telescopes out last night looking for it," he said.
Wesley, who has been keen on astronomy since he was a child, said telescopes and other astronomy equipment were so inexpensive now that the hobby had become a viable pastime for just about anybody. His own equipment cost about $10,000.
In many cases, particularly with planets such as Jupiter, professional space watchers were turning to amateurs to provide them with new discoveries.
"A lot of the professional astronomers have access to large scopes but those scopes are in demand for all sorts of other jobs and you just can't afford to tie up a large telescope worth millions of dollars looking at Jupiter every night," Wesley said.
"These large telescopes only get built because of the interests of the consortium parties, and those interests need to be attended to, so it's really left to amateurs who've got no fixed agenda to image whatever they find interesting."
Something has smashed into Jupiter, leaving behind a black spot in the planet's atmosphere, scientists confirmed on Monday.
This is only the second time such an impact has been observed. The first was almost exactly 15 years ago, when more than 20 fragments of comet Shoemaker-Levy 9 collided with the gas giant.
"This has all the hallmarks of an impact event, very similar to Shoemaker-Levy 9," said Leigh Fletcher, an astronomer at NASA's Jet Propulsion Lab in Pasadena, California. "We're all extremely excited."
The impact was discovered by amateur astronomer Anthony Wesley in Murrumbateman, Australia at about 1330 GMT on Sunday. Wesley noticed a black spot in Jupiter's south polar region - but he very nearly stopped observing before he saw it.
"By 1am I was ready to quit ... then changed my mind and decided to carry on for another half hour or so," he wrote in his observation report. Initially he suspected he was seeing one of Jupiter's moons or a moon's shadow on the planet, but the location, size and speed of the spot ruled out that possibility.
'Stroke of luck'
After checking images taken two nights earlier and not seeing the spot, he realised he had found something new and began emailing others.
Among the people he contacted were Fletcher and Glenn Orton, also at JPL. They had serendipitously scheduled observing time on NASA's InfraRed Telescope Facility in Hawaii for that night.
"It was a fantastic stroke of luck," Orton told New Scientist.
Their team began observations at about 1000 GMT on 20 July, and after six hours of observing confirmed that the spot was an impact and not a weather event.
"It's completely unlike any of the weather phenomena that we observe on Jupiter," Orton says.
Splash
The first clue was a near-infrared image of the upper atmosphere above the impact site. An impact would make a splash like a stone thrown into a pool, scattering material in the atmosphere upwards. This material would then reflect sunlight, appearing as a bright spot at near-infrared wavelengths.
And that's exactly what the team saw. "Our first image showed a really bright object right where that black scar was, and immediately we knew this was an impact," Orton says. "There's no natural phenomenon that creates a black spot and bright particles like that."
Supporting evidence came from measurements of Jupiter's temperature. Thermal images also showed a bright spot where the impact took place, meaning the impact warmed up the lower atmosphere in that area.
The researchers have also found hints of higher-than-normal amounts of ammonia in the upper atmosphere. Extra ammonia had been churned up by the previous Shoemaker-Levy comet impact.
Exotic chemistry
The Shoemaker-Levy impact also introduced some exotic chemistry into Jupiter's atmosphere. The energy from the collision fused some of the original atmospheric components into new molecules, such as hydrogen cyanide.
Scientists hope this new impact has done the same thing, since that would allow them to follow the new materials and learn how the atmosphere moves with time.
So what was the impactor? "Not a clue," Orton says. He speculates that it could have been a block of ice from somewhere in Jupiter's neighborhood, or a wandering comet that was too faint for astronomers to detect before the impact.
Without having seen it, scientists can't tell how large the object was. "But the impact scar we're seeing is about the same size as one of Jupiter's big storms, Oval BA, Fletcher told New Scientist. "That, I believe, is about the size of the Earth."
Santa
Barbara, Calif. - - Nanosized diamonds found just a few meters below
the surface of Santa Rosa Island off the coast of Santa Barbara provide strong evidence of a cosmic impact event in North America approximately 12,900 years ago,
according to a new study by scientists. Their hypothesis holds that
fragments of a comet struck across North America at that time.
The research, published this week in the Proceedings of the National Academy of Sciences (PNAS), was led by James Kennett, professor emeritus at UC Santa Barbara, and Douglas J. Kennett, first author, of the University of Oregon. The two are a father-son team. They were joined by 15 other researchers.
"The pygmy mammoth, the tiny island version of the North American mammoth, died off at this time," said James Kennett. "Since it coincides with this event, we suggest it is related." He explained that this site, with its layer containing hexagonal diamonds, is also associated with other types of diamonds and with dramatic environmental changes and wildfires. They are part of a sedimentary layer known as the Younger Dryas Boundary.
"There was a major event 12,900 years ago," said
James Kennett. "It is hard to explain this assemblage of materials
without a cosmic impact event and associated extensive wildfires. This
hypothesis fits with the abrupt climatic cooling as recorded in
ocean-drilled sediments beneath the Santa Barbara Channel. The cooling
resulted when dust from the high-pressure, high-temperature, multiple
impacts was lofted into the atmosphere, causing a dramatic drop in
solar radiation."
The tiny diamonds were buried below four meters of sediment and they correspond with the disappearance of the Clovis culture - - the first well-established and distributed North American peoples. An estimated 35 types of mammals and 19 types of birds also became extinct in North America about this time.
"The type of diamond we have found - - lonsdaleite - - is a shock-synthesized mineral defined by its hexagonal crystalline structure," said Douglas Kennett, associate professor of anthropology at the University of Oregon. "It forms under very high temperatures and pressures consistent with a cosmic impact. These diamonds have only been found thus far in meteorites and impact craters on earth, and appear to be the strongest indicator yet of a significant cosmic impact [during Clovis]."
The
diamonds were found in association with soot, which forms in extremely
hot fires, and they suggest associated regional wildfires, based on
nearby environmental records. Such soot and diamonds are rare in the
geological record. They were found in sediment dating to massive
asteroid impacts 65 million years ago in a layer widely known as the
K-T Boundary, known to be associated with the extinction of dinosaurs
and many other types of organisms.
James Kennett, former director of the Marine Science Institute at UCSB, is considered by some of his peers to be the "father" of marine geology and paleoceanography. The native of New Zealand notes that the sedimentary layers beneath the Santa Barbara Channel provide a unique window on the history of the world's climate and ocean changes. The area is one of the best locations in the world for this type of geological research.
Douglas Kennett received his bachelor's, master's, and Ph.D in anthropology at UCSB.
Co-authors on the PNAS paper are Jon M. Erlandson and Brendan J. Culleton, of the University of Oregon; Allen West of GeoScience Consulting in Arizona; G. James West of UC Davis; Ted E. Bunch and James H. Wittke, of Northern Arizona University; Shane S. Que Hee of UCLA; John R. Johnson of the Santa Barbara Museum of Natural History; Chris Mercer of UCSB and National Institute of Materials Science in Japan; Feng Shen of the FEI Company; Thomas W. Stafford of Stafford Research Inc. of Colorado; Wendy S. Wolbach and Adrienne Stich, of DePaul University in Chicago; and James C. Weaver of UC Riverside.
The National Science Foundation provided primary funding for this research.
© NASA/JPL-Caltech
About 20 per cent of the objects in the main asteroid belt may have gotten their start beyond Neptune, a new simulation suggests
About 20 per cent of the objects in the main asteroid belt may have gotten their start beyond Neptune, a new simulation suggests
"People have just been assuming that what we see there, formed there," says Hal Levison of the Southwest Research Institute in Boulder, Colorado.
But Levison and others suspect some 20 per cent of the asteroids in the belt may be comet-like objects that were born in colder climes, beyond the orbit of Neptune.
Scattered objects
The results come from new simulations using a theory called the Nice model, which suggests the solar system's giant planets were born closer together and were surrounded by a vast disc of leftovers from the planets' formation called planetesimals (see here).
According to the model, Jupiter and Saturn entered a tight orbital dance about 700 million years after the solar system formed. Their gravity then flung Uranus and Neptune out into the planetesimal disc like bowling balls, causing the objects there to scatter like pins.
Past simulations have tracked the trajectories of these planetesimals and showed they wind up forming the Kuiper belt of icy debris where Pluto sits, some of the distant satellites of Jupiter and Saturn, and Trojan asteroids, bodies that share Jupiter's orbit but are centred at two points ahead of and behind the planet.
Outer belt
The new simulation fed planetesimals into the region surrounding Jupiter and Saturn as the planets moved to see how many would be captured as so-called Hilda asteroids, a group outside the main asteroid belt that orbits the sun three times for each two orbits of Jupiter.
While some of the objects became Hildas and Trojans, most of the captured objects wound up in the outer portion of the solar system's main asteroid belt.
Indeed, the outer asteroid belt boasts objects that are thought to have ice, while the inner asteroid belt is dominated by rocky bodies. "The interpretation has been that this represents a change in the nebula or the disc from which the planets formed," Levison told New Scientist.
Partial simulation
But if these icy outer objects are newcomers, it would mean that objects in the asteroid belt did not all form close to their present locations. "It says to the community that the assumptions you've been making don't necessarily have to be true," Levison says.
But Renu Malhotra of the University of Arizona in Tucson says she's not convinced of the estimate that 20 per cent of the asteroids in the main belt could come from the outer solar system.
That's because the new study didn't simulate the process that knocked the planetesimals out of their original orbits - it only sent objects from the outer solar system inwards to find out what fraction would be captured.
"It's not clear how statistically probable this is," Malhotra says. The simplest hypothesis, she adds, is that most of the asteroids in the main belt are original residents.
Journal reference: Nature (vol 460, p 364)
Agence France-Presse
Thu, 16 Jul 2009 05:45 UTC
© AFP/NASA-HO/File
This November 2000 NASA file image shows a meteor streaking across the sky during the Leonid meteor shower. Many of the primitive bodies wandering the asteroid belt between Mars and Jupiter are former comets, tossed out of orbit by a brutal ballet between the giant outer planets, say a team of astrophysicists.
This November 2000 NASA file image shows a meteor streaking across the sky during the Leonid meteor shower. Many of the primitive bodies wandering the asteroid belt between Mars and Jupiter are former comets, tossed out of orbit by a brutal ballet between the giant outer planets, say a team of astrophysicists.
A commonly accepted theory is that the asteroid belt is the rubble left over from a "proto-planetary disk," the dense ring of gas that surrounds a new-born star.
But the orbiting rocks have long been a source of deep curiosity. They are remarkably varied, ranging from mixtures of ice and rock to igneous rocks, which implies they have jumbled origins.
The answer to the mystery, according to a study published by the British journal Nature on Wednesday, is that a "significant fraction" of the asteroid population in fact comprises ex-comets.
Famously described as "dirty snowballs" of ice and dust, comets are lonely, long-distance wanderers of the Solar System whose elliptical swing around the Sun can take decades.
Researchers in France and the United States ran a mathematical model of the development of the early Solar System, when the planets were accreting from clustering masses of dust and gas.
According to this model, the nascent giant planets -- Jupiter, Saturn, Uranus and Neptune -- orbited at this time in a pretty compact configuration, between five and 15 astronomical units (AUs) from the Sun.
An AU is a standard unit of measurement for Solar System distances. It equals the distance from the Earth to the Sun, or around 150 million kilometres (93 million miles).
Beyond the giant planets was a disk-shaped mass of comets, known as trans-Neptunian objects, between 16 and 30 AUs from the Sun.
As the giants became bigger and bigger, their orbits became unstable.
Eventually, after around 600 million years, Uranus and Neptune were kicked out by gravitational jousting.
They rammed into the disk of comets and scattered its members throughout the Solar System, according to this model. Many of them were captured by the weak gravitational force of the asteroid belt, where they remain to this day.
"It's a paradigm shift," said Matthieu Gounelle of France's National Centre for Scientific Research (CNRS) in a press release.
"The asteroid belt is not just a leftover from the formation of the Solar System, but also that of violent phenomena" including the great planetary migration.
If the model is right, it implies that the difference between the most primitive asteroids and comets is even slimmer than thought.
It would also shed light on the controversial origin of micrometeorites, or tiny extraterrestrial particles that survive the fiery passage through Earth's atmosphere.
Micrometeorites are different from meteorites in composition and texture, and this could be explained if they derive from comets, which are richer in organic material and crumblier than native asteroids.
Science Daily
Thu, 16 Jul 2009 08:41 UTC
© CSNSM-Orsay-CNRS / IPEV
Researchers collected this micrometeorite in the vicinity of CONCORDIA station in central Antarctica (Dome C, 73°S, 123°E)
Researchers collected this micrometeorite in the vicinity of CONCORDIA station in central Antarctica (Dome C, 73°S, 123°E)
The team used numerical simulations to show that some comet-like objects residing in a disk outside the original orbit of the planets were scattered across the solar system and into the outer asteroid belt during a violent phase of planetary evolution.
Usually, the solar system is considered a place of relative permanence, with changes occurring gradually over hundreds of millions to billions of years. New models of planet formation indicate, however, that at specific times, the architecture of the solar system experienced dramatic upheaval.
In particular, it now seems probable that approximately 3.9 billion years ago, the giant planets of our solar system -- Jupiter, Saturn, Uranus and Neptune -- rearranged themselves in a tumultuous spasm. "This last major event of planet formation appears to have affected nearly every nook and cranny of the solar system," says lead author Dr. Hal Levison of SwRI.
Key evidence for this event was first identified in the samples returned from the Moon by the Apollo astronauts. They tell us about an ancient cataclysmic bombardment where large asteroids and comets rained down on the Moon.
Scientists now recognize that this event was not limited solely to the Moon; it also affected the Earth and many other solar system bodies. "The existence of life on Earth, as well as the conditions that made our world habitable for us, are strongly linked to what happened at this distant time," states Dr. David Nesvorny of SwRI.
The same dynamical conditions that devastated the planets also led to the capture of some would-be impactors in the asteroid belt. "In the classic movie Casablanca, everybody comes to Rick's. Apparently throughout the solar system, the cool hangout for small objects is the asteroid belt," says Dr. William Bottke of SwRI.
Once in the asteroid belt, the embedded comet-like objects began to beat up both themselves and the asteroids. "Our model shows that comets are relatively easy to break up when hit by something, at least when compared to typical asteroids. It is unavoidable that some of the debris went on to land on asteroids, the Moon and the Earth. In fact, some of the leftovers may still be arriving today," says Dr. Alessandro Morbidelli of the Observatoire de la Cote d'Azur in Nice, France.
The team believes the surprising similarities between some micrometeorites landing on Earth and comet samples returned by NASA's Stardust mission are no accident. "There has been lots of debate about the nature of micrometeorites reaching the Earth," says Dr. Matthieu Gounelle of the Museum National d'Histoire Naturelle in Paris. "Some believe they are asteroidal, while others argue they are cometary. Our work suggests that in a sense, both camps may be right."
"Some of the meteorites that once resided in the asteroid belt show signs they were hit by 3.5 to 3.9 billion years ago. Our model allows us to make the case they were hit by captured comets or perhaps their fragments," adds Dr. Kleomenis Tsiganis of Aristotle University of Thessaloniki, Greece. "If so, they are telling us the same intriguing story as the lunar samples, namely that the solar system apparently went berserk and reconfigured itself about 4 billion years ago."
Overall, the main asteroid belt contains a surprising diversity of objects ranging from primitive ice/rock mixtures to igneous rocks. The standard model used to explain this assumes that most asteroids formed in place from a primordial disk that experienced radical chemical changes within this zone. This model shows, however, that the observed diversity of the asteroid belt is not a direct reflection of the intrinsic compositional variation of the proto-planetary disk. These results fundamentally change our view of the asteroid belt.
Additional tests of this model will come from studies of meteorites, the asteroid belt, planet formation and the Moon. "The Moon and the asteroid belt may be the best and most accessible places in the solar system to understand this critical part of solar system history," says Levison. "We believe key evidence from these cold airless bodies may help us unlock the biggest 'cold case' of all time."
Funding for this research was provided by NASA's Outer Planets Research and Origins of Solar Systems programs. Additional support was provided by NASA's Lunar Science Institute.
Journal reference:
1. Levison et al. Contamination of the asteroid belt by primordial trans-Neptunian objects. Nature, 2009; 460 (7253): 364 DOI: 10.1038/nature08094
Space Weather
Mon, 20 Jul 2009 03:42 UTC
© Anthony Wesley
"The jet-black mark is near Jupiter's south pole (south is up in the image)," says Wesley. "I have imagery of that same location from two nights earlier without the impact mark, so this is a very recent event. The material has already begun to spread out in a fan shape on one side, and should be rapidly pulled apart by the fast jetstream winds. I recorded a lot of footage, and will be generating more images and a rotation animation soon."
Amateur astronomers around the world should train their telescopes on Jupiter tonight to monitor the progress of this possible impact event: sky map. Stay tuned for more images and updates.
PhysOrg
Mon, 20 Jul 2009 22:41 UTC
© NOAA and UC Santa Barbara
This map shows California's Channel Islands with the islands of the previously combined islands of Santarosae encircled at the top.
This map shows California's Channel Islands with the islands of the previously combined islands of Santarosae encircled at the top.
In a paper appearing online ahead of regular publication in the Proceedings of the National Academy of Sciences, University of Oregon archaeologist Douglas J. Kennett and colleagues from nine institutions and three private research companies report the presence of shock-synthesized hexagonal diamonds in 12,900-year-old sediments on the Northern Channel Islands off the southern California coast.
These tiny diamonds and diamond clusters were buried deeply below four meters of sediment. They date to the end of Clovis -- a Paleoindian culture long thought to be North America's first human inhabitants. The nano-sized diamonds were pulled from Arlington Canyon on the island of Santa Rosa that had once been joined with three other Northern Channel Islands in a landmass known as Santarosae.
The diamonds were found in association with soot, which forms in extremely hot fires, and they suggest associated regional wildfires, based on nearby environmental records.
Such soot and diamonds are rare in the geological record. They were found in sediment dating to massive asteroid impacts 65 million years ago in a layer widely known as the K-T Boundary. The thin layer of iridium-and-quartz-rich sediment dates to the transition of the Cretaceous and Tertiary periods, which mark the end of the Mesozoic Era and the beginning of the Cenozoic Era.
"The type of diamond we have found -- Lonsdaleite -- is a shock-synthesized mineral defined by its hexagonal crystalline structure. It forms under very high temperatures and pressures consistent with a cosmic impact," Kennett said. "These diamonds have only been found thus far in meteorites and impact craters on Earth and appear to be the strongest indicator yet of a significant cosmic impact [during Clovis]."
© University of Oregon
This transmission electron microscopy close-up shows a single lonsdaleite crystal, left, and associated diffraction pattern.
This transmission electron microscopy close-up shows a single lonsdaleite crystal, left, and associated diffraction pattern.
In the Jan. 2, 2009, issue of the journal Science, a team led by Kennett reported the discovery of billions of nanometer-sized diamonds concentrated in sediments -- weighing from about 10 to 2,700 parts per billion -- in six North American locations.
"This site, this layer with hexagonal diamonds, is also associated with other types of diamonds and with dramatic environmental changes and wildfires," said James Kennett, paleoceanographer and professor emeritus in the Department of Earth Science at the University of California, Santa Barbara.
"There was a major event 12,900 years ago," he said. "It is hard to explain this assemblage of materials without a cosmic impact event and associated extensive wildfires. This hypothesis fits with the abrupt cooling of the atmosphere as shown in the record of ocean drilling of the Santa Barbara Channel. The cooling resulted when dust from the high-pressure, high-temperature, multiple impacts was lofted into the atmosphere, causing a dramatic drop in solar radiation."
The hexagonal diamonds from Arlington Canyon were analyzed at the UO's Lorry I. Lokey Laboratories, a world-class nanotechnology facility built deep in bedrock to allow for sensitive microscopy and other high-tech analyses of materials. The analyses were done in collaboration with FEI, a Hillsboro, Ore., company that distributes the high-resolution Titan microscope used to characterize the hexagonal diamonds in this study.
Transmission electron microscopy and scanning electron microscopes were used in the extensive analyses of the sediment that contained clusters of Lonsdaleite ranging in size from 20 to 1,800 nanometers. These diamonds were inside or attached to carbon particles found in the sediments.
These findings are inconsistent with the alternative and already hotly debated theory that overhunting by Clovis people led to the rapid extinction of large mammals at the end of the ice age, the research team argues in the PNAS paper. An alternative theory has held that climate change was to blame for these mass extinctions. The cosmic-event theory suggests that rapid climate change at this time was possibly triggered by a series of small and widely dispersed comet strikes across much of North America.
Asher Moses
Sydney Morning Herald
Tue, 21 Jul 2009 10:49 UTC
© NASA
Confirmed by NASA: A large impact on the left on Jupiter's south polar region captured on July 20, 2009, by NASA's Infrared Telescope Facility in Mauna Kea, Hawaii. Jupiter was slammed by an Earth-sized object exactly 15 years after Comet Schumacher-Levy did the same in 1994.
Confirmed by NASA: A large impact on the left on Jupiter's south polar region captured on July 20, 2009, by NASA's Infrared Telescope Facility in Mauna Kea, Hawaii. Jupiter was slammed by an Earth-sized object exactly 15 years after Comet Schumacher-Levy did the same in 1994.
Anthony Wesley, 44, a computer programmer from Murrumbateman, a village north of Canberra, made the discovery about 1am yesterday using his backyard 14.5-inch reflecting telescope.
The impact would have occurred no more than two days earlier and will only be visible for another few days.
Within hours, his images had spread across the internet on science websites.
NASA's Jet Propulsion Laboratory confirmed the discovery at 9pm yesterday using its large infrared telescope at the summit of Mauna Kea in Hawaii.
The only other time astronomers have discovered evidence of a space object having hit Jupiter was when the Shoemaker-Levy 9 comet collided with the giant planet in July, 1994.
That event was also the first direct observation of two objects colliding in space.
Glenn Orton, the NASA scientist who confirmed Wesley's discovery, said: "We are extremely lucky to be seeing Jupiter at exactly the right time, the right hour, the right side of Jupiter to witness the event. We couldn't have planned it better."
Orton said he was not yet sure whether the object that hit Jupiter was a comet, asteroid or some other piece of space junk. But the impact mark is about the size of the Earth.
"It's been a whirlwind of a day and this, on the anniversary of the Shoemaker-Levy 9 and Apollo anniversaries, is amazing," he said.
To most people the image is unremarkable and appears as little more than a scar on Jupiter's vast gas surface.
Leigh Fletcher, an astronomer who worked with Orton on confirming the discovery last night, said: "These are the most exciting observations I've seen in my five years of observing the outer planets."
Wesley said in a phone interview that documenting these sorts of impacts was the only way to get new data on how the solar system formed and what planets such as Jupiter are made of, as the impact throws up debris that would otherwise be invisible when looking through a telescope from Earth.
The collision also allows astronomers to examine Jupiter's role in cleaning up space debris in the solar system.
"If anything like that had hit the Earth it would have been curtains for us, so we can feel very happy that Jupiter is doing its vacuum-cleaner job and hoovering up all these large pieces before they come for us," he said.
"An impact event like this, even just knowing how often they happen, gives you some idea of how much debris is left over from the solar system when it formed and how quickly Jupiter is vacuuming up the remains of the bits and pieces floating around in the solar system."
Mike Salway, who runs the Australian amateur astronomy community website iceinspace.com.au, said astronomers around the world were raving about the discovery.
"Amateur astronomers are all over it at the moment - they all had their telescopes out last night looking for it," he said.
Wesley, who has been keen on astronomy since he was a child, said telescopes and other astronomy equipment were so inexpensive now that the hobby had become a viable pastime for just about anybody. His own equipment cost about $10,000.
In many cases, particularly with planets such as Jupiter, professional space watchers were turning to amateurs to provide them with new discoveries.
"A lot of the professional astronomers have access to large scopes but those scopes are in demand for all sorts of other jobs and you just can't afford to tie up a large telescope worth millions of dollars looking at Jupiter every night," Wesley said.
"These large telescopes only get built because of the interests of the consortium parties, and those interests need to be attended to, so it's really left to amateurs who've got no fixed agenda to image whatever they find interesting."
Lisa Grossman
New Scientist
Tue, 21 Jul 2009 17:38 UTC
© Paul Kalas/Michael Fitzgerald/Franck Marchis/LLNL/UCLA/UC Berkeley/SETI Institute
Infrared observations taken at the Keck II telescope in Hawaii reveal a bright spot where the impact occurred. The spot looks black at visible wavelengths
Infrared observations taken at the Keck II telescope in Hawaii reveal a bright spot where the impact occurred. The spot looks black at visible wavelengths
This is only the second time such an impact has been observed. The first was almost exactly 15 years ago, when more than 20 fragments of comet Shoemaker-Levy 9 collided with the gas giant.
"This has all the hallmarks of an impact event, very similar to Shoemaker-Levy 9," said Leigh Fletcher, an astronomer at NASA's Jet Propulsion Lab in Pasadena, California. "We're all extremely excited."
The impact was discovered by amateur astronomer Anthony Wesley in Murrumbateman, Australia at about 1330 GMT on Sunday. Wesley noticed a black spot in Jupiter's south polar region - but he very nearly stopped observing before he saw it.
"By 1am I was ready to quit ... then changed my mind and decided to carry on for another half hour or so," he wrote in his observation report. Initially he suspected he was seeing one of Jupiter's moons or a moon's shadow on the planet, but the location, size and speed of the spot ruled out that possibility.
'Stroke of luck'
After checking images taken two nights earlier and not seeing the spot, he realised he had found something new and began emailing others.
Among the people he contacted were Fletcher and Glenn Orton, also at JPL. They had serendipitously scheduled observing time on NASA's InfraRed Telescope Facility in Hawaii for that night.
"It was a fantastic stroke of luck," Orton told New Scientist.
Their team began observations at about 1000 GMT on 20 July, and after six hours of observing confirmed that the spot was an impact and not a weather event.
"It's completely unlike any of the weather phenomena that we observe on Jupiter," Orton says.
Splash
The first clue was a near-infrared image of the upper atmosphere above the impact site. An impact would make a splash like a stone thrown into a pool, scattering material in the atmosphere upwards. This material would then reflect sunlight, appearing as a bright spot at near-infrared wavelengths.
And that's exactly what the team saw. "Our first image showed a really bright object right where that black scar was, and immediately we knew this was an impact," Orton says. "There's no natural phenomenon that creates a black spot and bright particles like that."
Supporting evidence came from measurements of Jupiter's temperature. Thermal images also showed a bright spot where the impact took place, meaning the impact warmed up the lower atmosphere in that area.
The researchers have also found hints of higher-than-normal amounts of ammonia in the upper atmosphere. Extra ammonia had been churned up by the previous Shoemaker-Levy comet impact.
Exotic chemistry
The Shoemaker-Levy impact also introduced some exotic chemistry into Jupiter's atmosphere. The energy from the collision fused some of the original atmospheric components into new molecules, such as hydrogen cyanide.
Scientists hope this new impact has done the same thing, since that would allow them to follow the new materials and learn how the atmosphere moves with time.
So what was the impactor? "Not a clue," Orton says. He speculates that it could have been a block of ice from somewhere in Jupiter's neighborhood, or a wandering comet that was too faint for astronomers to detect before the impact.
Without having seen it, scientists can't tell how large the object was. "But the impact scar we're seeing is about the same size as one of Jupiter's big storms, Oval BA, Fletcher told New Scientist. "That, I believe, is about the size of the Earth."
Gail Gallessich
University of California - Santa Barbara
Tue, 21 Jul 2009 23:45 UTC
© UCSB
This is James Kennett (left) and Douglas J. Kennett.
This is James Kennett (left) and Douglas J. Kennett.
The research, published this week in the Proceedings of the National Academy of Sciences (PNAS), was led by James Kennett, professor emeritus at UC Santa Barbara, and Douglas J. Kennett, first author, of the University of Oregon. The two are a father-son team. They were joined by 15 other researchers.
"The pygmy mammoth, the tiny island version of the North American mammoth, died off at this time," said James Kennett. "Since it coincides with this event, we suggest it is related." He explained that this site, with its layer containing hexagonal diamonds, is also associated with other types of diamonds and with dramatic environmental changes and wildfires. They are part of a sedimentary layer known as the Younger Dryas Boundary.
© James C. Weaver
Here are hexagonal nanodiamonds discovered on Santa Rosa Island.
Here are hexagonal nanodiamonds discovered on Santa Rosa Island.
The tiny diamonds were buried below four meters of sediment and they correspond with the disappearance of the Clovis culture - - the first well-established and distributed North American peoples. An estimated 35 types of mammals and 19 types of birds also became extinct in North America about this time.
"The type of diamond we have found - - lonsdaleite - - is a shock-synthesized mineral defined by its hexagonal crystalline structure," said Douglas Kennett, associate professor of anthropology at the University of Oregon. "It forms under very high temperatures and pressures consistent with a cosmic impact. These diamonds have only been found thus far in meteorites and impact craters on earth, and appear to be the strongest indicator yet of a significant cosmic impact [during Clovis]."
© James Kennett
This image shows a dark layer of sediment is exposed in Arlington Canyon on Santa Rosa Island.
This image shows a dark layer of sediment is exposed in Arlington Canyon on Santa Rosa Island.
James Kennett, former director of the Marine Science Institute at UCSB, is considered by some of his peers to be the "father" of marine geology and paleoceanography. The native of New Zealand notes that the sedimentary layers beneath the Santa Barbara Channel provide a unique window on the history of the world's climate and ocean changes. The area is one of the best locations in the world for this type of geological research.
Douglas Kennett received his bachelor's, master's, and Ph.D in anthropology at UCSB.
Co-authors on the PNAS paper are Jon M. Erlandson and Brendan J. Culleton, of the University of Oregon; Allen West of GeoScience Consulting in Arizona; G. James West of UC Davis; Ted E. Bunch and James H. Wittke, of Northern Arizona University; Shane S. Que Hee of UCLA; John R. Johnson of the Santa Barbara Museum of Natural History; Chris Mercer of UCSB and National Institute of Materials Science in Japan; Feng Shen of the FEI Company; Thomas W. Stafford of Stafford Research Inc. of Colorado; Wendy S. Wolbach and Adrienne Stich, of DePaul University in Chicago; and James C. Weaver of UC Riverside.
The National Science Foundation provided primary funding for this research.
John Hayes
UFOINFO
Wed, 22 Jul 2009 14:59 UTC
Posted: July 22, 2009
Date: June 24th 2009
Time: Daylight hour 6:57pm CDST
Number of witnesses: One
Number of objects: One
Shape of objects: Round, Ball shaped
Weather Conditions: Clear
Description: Small fireball traveling from Northeast to Southwest north of Granbury Texas. Not so spectacular with the exception that it was still during bright daylight. I suspect it was a meteorite.
TV/Radio: I won't report but if someone else does I would like to be informed.
[Note: This fireball/meteor report is included for reference purposes - John @ UFOINFO.]
The list
of cosmic objects that could hit Earth is growing. Scientists study
satellite 'tractors' and nuclear weapons as ways to divert asteroids
headed our way.
When an object smacked into Jupiter over the weekend, giving astronomers their best cosmic-collision show since the comet Shoemaker-Levy 9 in 1994, the giant gas ball of a planet took the poke like the Pillsbury Dough Boy.
For all its scientific interest, however, the collision also serves as a stark reminder that the solar system remains a shooting gallery - with Earth, as well as Jupiter, on the wrong side of the firing line.
The object's signature on Jupiter's cloud tops initially was discovered by Australian amateur astronomer Anthony Wesley as he gathered digital images of the giant planet through his 14.5-inch telescope. After alerting other astronomers to what appeared to be a "scar" in the cloud tops similar to those generated by the pieces of Shoemaker-Levy 9, NASA scientists trained a 3-meter (9.8-foot) infrared telescope on the planet and got a good look at the scar.
"It could be the impact of a comet," according to Glenn Orton, a scientist at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., in a statement yesterday. "But we don't know for sure yet."
When it comes to objects Earthlings should keep an eye on, the catalog scientists have amassed is swelling.
Since 1995, astronomers associated with 10 search projects have discovered more than 6,200 near-Earth asteroids of all sizes, according to data from JPL. Some 784 are at least a kilometer (0.62 miles) across or larger. Just over 1,000 of the total have been deemed "potentially hazardous" - those that pass Earth at a distance of less than 4.7 million miles.
And while the biggest ones have the potential to inflict the most damage, scientists are gaining a new appreciation of the punch even small ones can deliver.
Two and a half years ago, scientists at Sandia National Laboratories in Albuquerque, N.M., conducted advanced supercomputer simulations of the June 1908 event over Siberia that flattened and scorched trees over a region 30 miles across. Estimates put the explosive clout of the air burst from either a meteor or comet fragment at between 10 and 20 megatons.
The good news: Calculations on Sandia's supercomputer, in 3-D, push that explosive yield down to between three and five megatons. The bad news: The calculations also indicated that the asteroid or comet fragment was much smaller than previously estimated. There are more small asteroids hurtling around us than large ones.
Sometimes they can seem to come out of nowhere.
Last October, astronomers detected an asteroid an estimated two to five meters across. Some 21 hours later, it entered the atmosphere over northern Sudan sprinkling the Nubian desert with meteorites. The object's blast was estimated at roughly 1,000 tons of TNT.
For asteroid specialists, this was a live-fire test of protocols they'd developed to alert astronomers to monitor the object to refine orbital and impact-location estimates - and to alert national authorities that a direct hit was on the way.
The incident "underscored the successful evolution of the Near-Earth Object Program's discovery and orbit-prediction process," wrote JPL scientists Steve Chesley, Paul Chodas, and Don Yeomans in a post-event report on the incident.
The goal, of course, is to spot these objects and produce highly refined orbit estimates in time to take defensive action, if necessary.
And what might that action look like?
In a lengthy analysis of options that earned him a newly-minted PhD in aeronautical engineering from the University of Glasgow, Joan Pau Sanchez Cuartielles sorts through several approaches ranging from detonating a small nuclear bomb near an asteroid to using a modest-sized satellite as a kind of tractor that tugs the asteroid into a less dangerous orbit, connected to the asteroid by their mutual gravity.
The stand-off nuclear option (with an explosive yield tailored to the mass and density of the asteroid) turned out to be the most effective, although politically troublesome. The gravity tug could be effective with long lead times, or if the goal is to nudge an asteroid just enough to ensure it avoids a gravitational sweet spot, or keyhole, that would put it on a collision course with Earth decades into the future.
Comment: The reader might also want to read Meteorites, Asteroids, and Comets: Damages, Disasters, Injuries, Deaths, and Very Close Calls.
After
getting whacked unexpectedly by a small comet or asteroid, Jupiter is
sporting a "bruise," which has been big news this week. In visible
wavelengths, the impact site appears as a black spot. But in a new
image taken in near infrared by the Gemini North telescope on Mauna
Kea, Hawai'i, the spot shows up in spectacular glowing yellow.
"We utilized the powerful mid-infrared capabilities of the Gemini telescope to record the impact's effect on Jupiter's upper atmosphere," said Imke de Pater from the University of California, Berkeley. "At these wavelengths we receive thermal radiation (heat) from the planet's upper atmosphere. The impact site is clearly much warmer than its surroundings, as shown by our image taken at an infrared wavelength of 18 microns."
As Universe Today reported earlier, this new spot on Jupiter was first seen by Australian amateur astronomer Anthony Wesley on July 19th. This set off a flurry of activity as the large ground based observatories have imaged Jupiter in attempt to learn more about the impact and the object that struck Jupiter. Astronomers now say the object was likely a small comet or asteroid, just a few hundreds of meters in diameter. Such small bodies are nearly impossible to detect near or beyond Jupiter unless they reveal cometary activity, or, as in this case, make their presence known by impacting a giant planet.
In infrared, the impact site shows up in remarkable detail. "The structure of the impact site is eerily reminiscent of the larger Shoemaker-Levy 9 sites 15 years ago," remarked Heidi Hammel (Space Science Institute), who was part of the team that supported the effort at Gemini. In 1994, Hammel led the Hubble Space Telescope team that imaged Jupiter when it was pummeled by a shattered comet. "The morphology is suggestive of an arc-like structure in the feature's debris field," Hammel noted.
The Gemini images were obtained with the MICHELLE spectrograph/imager, yielding a series of images at 7 different mid-infrared wavelengths. Two of the images (8.7 and 9.7 microns) were combined into a color composite image by Travis Rector at the University of Alaska, Anchorage to create the final false-color image. By using the full set of Gemini images taken over a range of wavelengths from 8 to 18 microns, the team will be able to disentangle the effects of temperature, ammonia abundance, and upper atmospheric aerosol content. Comparing these Gemini observations with past and future images will permit the team to study the evolution of features as Jupiter's strong winds disperse them.
"The Gemini support staff made a heroic effort to get these data," said de Pater. "We were on the telescope observing within 24 hours of contacting the observatory." Because of the transient nature of this event, the telescope was scheduled as a "Target of Opportunity" and required staff to react quickly to the request."
Comment: Have you read Stephen Hawking: Space debris represents biggest natural threat to humanity?
Stephen
Hawking believes that one of the major factors in the possible scarcity
of intelligent life in our galaxy is the high probability of an
asteroid or comet colliding with inhabited planets. "We have observed,"
Hawking points out in Life in the Universe, "the collision of a comet,
Schumacher-Levi, with Jupiter (below), which produced a series of
enormous fireballs, plumes many thousands of kilometers high, hot
"bubbles" of gas in the atmosphere, and large dark "scars" on the
atmosphere which had lifetimes on the order of weeks."
It is thought the collision of a rather smaller body with the Earth, about 70 million years ago, was responsible for the extinction of the dinosaurs. A few small early mammals survived, but anything as large as a human, would have almost certainly been wiped out.
Through Earth's history such collisions occur, on the average every one million year. If this figure is correct, it would mean that intelligent life on Earth has developed only because of the lucky chance that there have been no major collisions in the last 70 million years. Other planets in the galaxy, Hawking believes, on which life has developed, may not have had a long enough collision free period to evolve intelligent beings.
"The threat of the Earth being hit by an asteroid is increasingly being accepted as the single greatest natural disaster hazard faced by humanity," according to Nick Bailey of the University of Southampton's School of Engineering Sciences team, who has developed a threat identifying program.
The team used raw data from multiple impact simulations to rank each country based on the number of times and how severely they would be affected by each impact. The software, called NEOimpactor (from NASA's "NEO" or Near Earth Object program), has been specifically developed for measuring the impact of 'small' asteroids under one kilometer in diameter.
Early results indicate that in terms of population lost, China, Indonesia, India, Japan and the United States face the greatest overall threat; while the United States, China, Sweden, Canada and Japan face the most severe economic effects due to the infrastructure destroyed.
The top ten countries most at risk are China, Indonesia, India, Japan, the United States, the Philippines, Italy, the United Kingdom, Brazil and Nigeria.
"The consequences for human populations and infrastructure as a result of an impact are enormous," says Bailey. "Nearly one hundred years ago a remote region near the Tunguska River witnessed the largest asteroid impact event in living memory when a relatively small object (approximately 50 meters in diameter) exploded in mid-air. While it only flattened unpopulated forest, had it exploded over London it could have devastated everything within the M25. Our results highlight those countries that face the greatest risk from this most global of natural hazards and thus indicate which nations need to be involved in mitigating the threat."
What would happen to the human species and life on Earth in general if an asteroid the size of the one that created the famous K/T Event of 65 million years ago at the end of the Mesozoic Era that resulted in the extinction of the dinosaurs impacted our planet.
As Stephen Hawking says, the general consensus is that any comet or asteroid greater than 20 kilometers in diameter that strikes the Earth will result in the complete annihilation of complex life - animals and higher plants. (The asteroid Vesta, for example, one of the destinations of the Dawn Mission, is the size of Arizona).
How many times in our galaxy alone has life finally evolved to the equivalent of our plants and animals on some far distant planet, only to be utterly destroyed by an impact? Galactic history suggests it might be a common occurrence.
The first thing to understand about the KT event is that it was absolutely enormous: an asteroid (or comet) six to 10 miles in diameter streaked through the Earth's atmosphere at 25,000 miles an hour and struck the Yucatan region of Mexico with the force of 100 megatons - the equivalent of one Hiroshima bomb for every person alive on Earth today. Not a pretty scenario!
Recent calculations show that our planet would go into another "Snowball Earth" event like the one that occurred 600 million years ago, when it is believed the oceans froze over (although some scientists dispute this hypothesis -see link below).
While microbial bacteria might readily survive such calamitous impacts, our new understanding from the record of the Earth's mass extinctions clearly shows that plants and animals are very susceptible to extinction in the wake of an impact.
Impact rates depend on how many comets and asteroids exist in a particular planetary system. In general there is one major impact every million years - a mere blink of the eye in geological time. It also depends on how often those objects are perturbed from safe orbits that parallel the Earth's orbit to new, Earth-crossing orbits that might, sooner or later, result in a catastrophic K/T or Permian-type mass extinction.
The asteroid that hit Vredefort located in the Free State Province of South Africa is one of the largest to ever impact Earth, estimated at over 10 km (6 miles) wide, although it is believed by many that the original size of the impact structure could have been 250 km in diameter, or possibly larger (though the Wilkes Land crater in Antarctica, if confirmed to have been the result of an impact event, is even larger at 500 kilometers across). The town of Vredefort is situated in the crater (image).
Dating back 2,023 million years, it is the oldest astrobleme found on earth so far, with a radius of 190km, it is also the most deeply eroded. Vredefort Dome Vredefort bears witness to the world's greatest known single energy release event, which caused devastating global change, including, according to many scientists, major evolutionary changes.
What has kept the Earth "safe" at least the past 65 million years, other than blind luck is the massive gravitational field of Jupiter, our cosmic guardian, with its stable circular orbit far from the sun, which assures a low number of impacts resulting in mass extinctions by sweeping up and scatters away most of the dangerous Earth-orbit-crossing comets and asteroids
Comment:
More
than 100 years have passed since the Tunguska Meteorite Event and the
mystery of its occurrence remains unsolved, but scientists have not
given up on solving the riddle. This July, an international research
group from Italy and the United States ventured into deepest Siberia to
investigate the most likely explanations of the mysterious event, and RIA Novosti correspondent David Burghardt joined them.
On June 30, 1908, Eastern Siberia was hit by an explosion equal to 2,000 times the nuclear bomb that destroyed the Japanese city of Hiroshima in 1945, destroying 2,200 square kilometers of taiga and flattening tens of millions of trees. If this impact had occurred four hours later, the city of St. Petersburg and other nearby villages would have been wiped off the face of the earth.
Travel to epicenter
Some 15 hours after the devastating impact, the skies throughout Europe were lit up for several nights and white nights were noted in places that had never experienced such a phenomenon. Witnesses at the time in Britain, Denmark and Germany said they were able to read a newspaper in the middle of the night without using any artificial light.
It was not until the winter of 1927-1928 that the first expedition was organized to investigate reports from witnesses of the event. The expedition was led by Russian scientist Leonid Kulik, who headed for the epicenter in search for the meteorite he believed was the only possible explanation for the event.
Travel back then to such a remote area was a very expensive and grueling affair, taking first a train to Krasnoyarsk in Eastern Siberia, and then traveling north on foot for hundreds of kilometers. Kulik's first expedition 19 years after the event enlisted numerous native Evenki guides and dozens of reindeer. Kulik, like hundreds of scientists after him, found no traces of a meteorite.
Travel to the area today is much easier than in Kulik's time, taking an airplane from Moscow to Krasnoyarsk, then a small prop plane to the village of Vanavara, and finally a Russian Mi-8 cargo helicopter into the region of the epicenter.
The two-week expedition included six professors from the University of Bologna, the University of Florence, and Cornell University.
There are some 100 theories of the Tunguska Event, including some of the more bizarre ones of a UFO crash site, a WWII bomber caught in a time warp and returning to 1908, Earth crossing through a black hole, and a cloud of mosquitoes that spontaneously combusted due to heat created by flying too densely.
The first theory was created in 1908 by native Evenki tribes in Eastern Siberia who were the actual witnesses of the event. According to their legend, the fire god, Agdy, became angered and destroyed all that was living in the area. Witnesses said there were several deafening explosions and trees were heard falling thousands of miles away.
The researchers looked at two of the most probable theories: meteorite impact and volcanic gas vent explosion. The scientific expedition was divided into two camps, one at Lake Cheko, where they were researching the meteorite theory, and the other at Kulik's Cabin near the epicenter (some 10 kilometers from the first group), where they were researching geological explanations for the blast.
Meteorite Impact Theory (Lake Cheko)
Of the hundreds of expeditions into the epicenter or impact area, not one has found any evidence that a meteorite struck the Earth's surface. Pieces of a meteorite have never been discovered and no crater has been confirmed anywhere in the area.
Four professors from the University of Bologna, Carlo Stanghellini, Maurizio Serrazanetti, Romano Serra, and Marco Cocchi, believe Lake Cheko was created by a meteorite impact due to its shape and tree growth in the area. The lake is elliptical (approximately 100 meters by 300 meters) rather than round, which is consistent with other lakes and swamps in the area.
However, no impact ring or rim residue has been discovered at the lake, which would be noticeable had a meteorite created the lake. The native Evenki say that the lake has always been there and the name comes from the Evenki language meaning "dark waters."
Professors Stanghellini and Serrazanetti focused their research on the lake bottom using both technical and not so technical equipment, including a magnetometer, radar, underwater camera and grappling hooks.
The scientists used a magnetometer to locate magnetic elements on the floor of the lake such as iron or other metallic elements, which would indicate that a meteorite or its fragments were on the bottom. Stanghellini described a magnetometer as a sophisticated compass that will show peaks on a monitor if it finds something metal.
He said that just like a regular compass, if you set a piece of metal near it, the arrow will point to the metal piece and not to the magnetic North. Because of the magnetometer's sensitivity, the scientists did their research on an inflatable rubber raft using wooden oars so as not spike the instrument. Before the process, they flagged
the entire lake in 10-meter swaths. They discovered a small anomaly in the center of the lake on one of the passes and said they would study the data more thoroughly on their return to Italy. On the following day, however, the magnetic anomaly was not detected on the screen and the scientists did not collect any other substantial evidence to support their theory that there are meteorite fragments on the bottom of the lake.
They also conducted radar soundings and underwater filming, but again came up with no substantial evidence.
Grappling hooks were dragged along the lake bottom to recover debris. They recovered mostly small branches and roots, which may or may not have been from 1908. The scientists said that the debris could have been under a thick layer of silt that would have preserved the debris, though they may have been recently deposited by the stream flowing into the lake. These samples were packed and sent to the university to define their age and find any proof of impact damage to them.
Stanghellini said further research of the lake's bottom was necessary, especially in drilling a core sample beneath the lake, though this would require international support and financing.
On shore, professors Serra and Cocchi cut down several trees and collected slabs as well as core samples of trees that survived the 1908 event, trees that were destroyed after the event and younger trees that appeared after the event. Samples were taken on the North and South side of Lake Cheko.
According to their preliminary studies, the samples showed that the trees had tight rings prior to the 1908 event, which means the trees grew very slowly due to competition with other trees and were growing densely together. Serra said that in 1908, the trees show scars with resin deposits (pitch) and then a very slow growth rate for two years due to shock. After 1910, the trees show much wider rings, which indicate there was less competition with other trees, more sunlight and nutrients.
He also said that the coniferous trees in the area should be associated with trees from the taiga and not lakeside forests, where there is usually heavy underbrush. Serra said that tree samples taken 4-50 meters from the lake are similar in growth patterns of trees 2-3 kilometers away from the lake prior to 1908, indicating that all of the trees are native to a taiga environment and not a lake.
He added that a significant growth change occurred in the trees located by the lake after 1908; whereas, those trees kilometers away from the lake continued to have tight rings due to slow growth and competition.
Serra noted that the survivor trees were much smaller during the 1908 event, meaning that they were bent over or twisted during the impact. All of the large trees, on the other hand, were uprooted. He said this is similar to what happens to trees during a hurricane. He also noted that the tree samples taken near Lake Cheko were similar to those taken after the Chernobyl nuclear reactor meltdown site in Ukraine in 1986.
Evidence collected in previous expeditions by Serra showed that tree limbs from 1908 contained deposits of magnesium, titanium, sulfurs, and several undefined elements, which would support the theories of a meteorite or even volcanic activity.
All four of the Italian researchers at Lake Cheko believe the lake was created by one of three impacts in 1908: the first exploded in the atmosphere, the second struck the ground, creating Lake Cheko and changing the direction of the creek, and the third struck the ground further North at the epicenter, presumably creating several deep bogs. They agreed that the meteorite that created the lake would have been 1-5 meters in diameter and the tree growth around the lake proved that it was created in 1908.
Cocchi did much research on an old creek bed that the scientists assume was cut off or rerouted after the 1908 event. Difficulties in researching the creek bed arise due to the fact that 20 centimeters under the surface there is permafrost that cannot be dug up. Drilling the creek bed is also planned to get a core sample in order to estimate when the creek changed its course and began flowing into the lake after it was created by the meteorite, according to the scientists.
Volcanic Gas Vent Explosion Theory (Tunguska Epicenter)
Jason Phipps Morgan, a geophysicist from Cornell University, and Paola Vanucchi, a geologist and geophysicist from the University of Florence, believe that the 1908 event was the result of a gas vent explosion created from the center of the earth. They did much investigation around the epicenter, especially what is called John's Rock, which is a 10-12 ton rock formation that is free-standing.
According to Morgan, this rock was actually "burped up" when the gas vent exploded, pushing the rock to the surface through a funnel. Morgan named the still unconfirmed funnel after his colleague, Paola's Funnel. He noted that this rock is the only one of its kind in the area and is definitely of volcanic nature. The scientists collected some 30 kilograms of rock samples, especially quartz and quartzite, from and around John's Rock, in search of shocked quartz, which would indicate that there was volcanic activity in the area.
Vanucchi said that some of the rock samples showed traces of being shocked, or fractured, and further research on the samples would be completed in both Italy and the United States. She also said that they believe they have found the main vent of the volcanic gas explosion very near to John's Rock.
The researchers revealed that the Russian geological mineral map they were supplied with was incorrect in many places in regard to the elements found in the area, as well as to the depth of some of the quartz deposits. Vanucchi said that they had started updating the existing map, but further research would be needed to perfect it.
The scientists were also interested in Churgym Waterfall which showed one of the largest samples of volcanic basalt in the world, indicating millions of years of volcanic activity in the area. There was a constant flow of lava, which is visible in layers around the falls and stream. Only some 30 meters of the basalt is above the surface, which is visible due to erosion by the stream and there is no estimate of how deep the volcanic rock extends beneath the earth.
Morgan said the amount of basalt in the area is so great that it proves the existence of constant volcanic activity for millions of years. Samples from the waterfall area were also taken for comparison with those from the John's Rock location. Though lava has ceased to reach the surface, lava vents still exist and can build up pressure and blow, thus creating a blast like that in the epicenter.
Comet Theory
One of the most commonly acceptable theories today is that of a comet or a piece from the tail of a comet hitting the Earth's surface. Upon returning to Moscow, RIA Novosti spoke with two Russian scientists on the comet theory.
Vitaly Romeiko, the director of the Department of Astrophysics at Zvenigorod Observatory, said in an interview in Moscow that the 1908 event was caused by a fragment of the Encke Comet's tail that entered the Earth's atmosphere as a ball of ice with small interplanetary fragments (dust particles) and, upon entrance, exploded due to the negative ions in the comet and the positive ions found on Earth. He pointed out that the Encke Comet also revolves around the sun and comes near Earth every 3.3 years.
Romeiko has participated in 23 expeditions into the Tunguska region.
Olga Gladysheva, a senior fellow at the A.F. Ioffe Physics and Technical Institute in St. Petersburg, supported Romeiko's theory in a separate interview with RIA Novosti, adding that the part of the comet's tail separated and created a giant ice ball that was created in a vacuum, and, therefore, made several explosions as the particles inside expanded and the ball disintegrated.
The Russian scientists base their theory on the fact on the absence of any meteorite material in the area, no rock fragments, or no impact areas that would create a crater.
Gladysheva said part of the comet's tail entered the Earth's ionosphere at more than 80 kilometers above ground, which is an intense area of atmospheric electricity. She said a major blast occurred over the epicenter at an altitude of 7-10 kilometers above the Earth's surface. The significance of the blast was due to the overly charged ions and differences in the positive and negative poles in the comet and Earth.
Romeiko said the ice ball that formed around the comet's dust particles before striking Earth would explain the absence of a crater or meteorite particles. The particles from the comet would be very minute and could most likely be found in the lower layers of peat moss in the area, which is frozen in permafrost.
101 Years Of An Unsolved Mystery
In separate conversations with the researchers during the expedition into the Tunguska epicenter, they all shared the same idea that the mystery will never be solved because scientists with their own theories and hypotheses will never agree on one single explanation. In regard to this, Romeiko said: "No one will back down on a theory that he has defended his entire life because that would mean failure."
Although the researchers returned without any substantial explanations for the event, they plan on returning to Tunguska to continue their research and prove their theories. Serra said there would be interest in the Tunguska Event far into the future, because the best scientists from around the world have been there and no one has come up with an explanation, which scientists simply cannot accept.
When the Italian and American research group left the epicenter, a new group of Russian "scientists" arrived. One of the group members said that she had worked with a psychic to identify which swamp a UFO had collided into in 1908.
Upon returning to the town of Vanavara, some 65 kilometers to the South of the epicenter, the Tunguska Reserve director, Ludmila Logunova, said that they know where the meteorite is located, but if they reveal its location, people would stop visiting the region.
Comment: For an in-depth review, read Tunguska, Psychopathy and the Sixth Extinction.
An intense bright spot has appeared in the clouds of Venus. Could it be associated with volcanic activity on the surface?
The Solar System is breaking out in spots. First Jupiter took a smack from a passing asteroid or comet, manifesting as a dark scar in the Jovian atmosphere, and now Venus is sporting a brilliant white spot in its southern polar region.
In an alert to fellow amateur astronomers, Venus observer Frank Melillo reports on his images captured on 19 July: "I have seen bright spots before but this one is an exceptional bright and quite intense area."
He suggests that it could be explained as an atmospheric effect, but could it be a sign of volcanic activity at the planet's surface? Venus is covered in a thick cloak of clouds which prevents any visible observation of the surface. Instead, radar is used to map the surface, but volcanic activity has never been observed directly.
"A volcanic eruption would be nice, but let's wait and find out!" says Venus specialist Dr Sanjay Limaye of the University of Wisconsin. "An eruption would have to be quite energetic to get a cloud this high." Furthermore, at a latitude of 50 degrees south, the spot lies outside the region of known volcanoes on Venus.
Melillo comments that the spot will not be seen again as intense as it is now, thanks to the rapid rotation of the planet's atmosphere. "I hope that someone will image Venus on Thursday when this part of the atmosphere is facing us again," he says.
Further observations will help shed light on the genesis of the bright spot and how it evolves as the atmosphere churns over.
Comment: Volcanic eruptions? Somebody knows what's really going on . . .
Military Hush-Up: Incoming Space Rocks Now Classified
Nothing to see here folks, please move along . . .
Date: June 24th 2009
Time: Daylight hour 6:57pm CDST
Number of witnesses: One
Number of objects: One
Shape of objects: Round, Ball shaped
Weather Conditions: Clear
Description: Small fireball traveling from Northeast to Southwest north of Granbury Texas. Not so spectacular with the exception that it was still during bright daylight. I suspect it was a meteorite.
TV/Radio: I won't report but if someone else does I would like to be informed.
[Note: This fireball/meteor report is included for reference purposes - John @ UFOINFO.]
Peter N. Spotts
The Christian Science Monitor
Tue, 21 Jul 2009 20:01 UTC
© NASA/Reuters
This detail image shows a large impact shown on the bottom left on Jupiter's south polar region captured on July 20, by NASA's Infrared Telescope Facility in Mauna Kea, Hawaii
This detail image shows a large impact shown on the bottom left on Jupiter's south polar region captured on July 20, by NASA's Infrared Telescope Facility in Mauna Kea, Hawaii
When an object smacked into Jupiter over the weekend, giving astronomers their best cosmic-collision show since the comet Shoemaker-Levy 9 in 1994, the giant gas ball of a planet took the poke like the Pillsbury Dough Boy.
For all its scientific interest, however, the collision also serves as a stark reminder that the solar system remains a shooting gallery - with Earth, as well as Jupiter, on the wrong side of the firing line.
The object's signature on Jupiter's cloud tops initially was discovered by Australian amateur astronomer Anthony Wesley as he gathered digital images of the giant planet through his 14.5-inch telescope. After alerting other astronomers to what appeared to be a "scar" in the cloud tops similar to those generated by the pieces of Shoemaker-Levy 9, NASA scientists trained a 3-meter (9.8-foot) infrared telescope on the planet and got a good look at the scar.
"It could be the impact of a comet," according to Glenn Orton, a scientist at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., in a statement yesterday. "But we don't know for sure yet."
When it comes to objects Earthlings should keep an eye on, the catalog scientists have amassed is swelling.
Since 1995, astronomers associated with 10 search projects have discovered more than 6,200 near-Earth asteroids of all sizes, according to data from JPL. Some 784 are at least a kilometer (0.62 miles) across or larger. Just over 1,000 of the total have been deemed "potentially hazardous" - those that pass Earth at a distance of less than 4.7 million miles.
And while the biggest ones have the potential to inflict the most damage, scientists are gaining a new appreciation of the punch even small ones can deliver.
Two and a half years ago, scientists at Sandia National Laboratories in Albuquerque, N.M., conducted advanced supercomputer simulations of the June 1908 event over Siberia that flattened and scorched trees over a region 30 miles across. Estimates put the explosive clout of the air burst from either a meteor or comet fragment at between 10 and 20 megatons.
The good news: Calculations on Sandia's supercomputer, in 3-D, push that explosive yield down to between three and five megatons. The bad news: The calculations also indicated that the asteroid or comet fragment was much smaller than previously estimated. There are more small asteroids hurtling around us than large ones.
Sometimes they can seem to come out of nowhere.
Last October, astronomers detected an asteroid an estimated two to five meters across. Some 21 hours later, it entered the atmosphere over northern Sudan sprinkling the Nubian desert with meteorites. The object's blast was estimated at roughly 1,000 tons of TNT.
For asteroid specialists, this was a live-fire test of protocols they'd developed to alert astronomers to monitor the object to refine orbital and impact-location estimates - and to alert national authorities that a direct hit was on the way.
The incident "underscored the successful evolution of the Near-Earth Object Program's discovery and orbit-prediction process," wrote JPL scientists Steve Chesley, Paul Chodas, and Don Yeomans in a post-event report on the incident.
The goal, of course, is to spot these objects and produce highly refined orbit estimates in time to take defensive action, if necessary.
And what might that action look like?
In a lengthy analysis of options that earned him a newly-minted PhD in aeronautical engineering from the University of Glasgow, Joan Pau Sanchez Cuartielles sorts through several approaches ranging from detonating a small nuclear bomb near an asteroid to using a modest-sized satellite as a kind of tractor that tugs the asteroid into a less dangerous orbit, connected to the asteroid by their mutual gravity.
The stand-off nuclear option (with an explosive yield tailored to the mass and density of the asteroid) turned out to be the most effective, although politically troublesome. The gravity tug could be effective with long lead times, or if the goal is to nudge an asteroid just enough to ensure it avoids a gravitational sweet spot, or keyhole, that would put it on a collision course with Earth decades into the future.
Comment: The reader might also want to read Meteorites, Asteroids, and Comets: Damages, Disasters, Injuries, Deaths, and Very Close Calls.
Universe Today
Thu, 23 Jul 2009 16:22 UTC
© Gemini Observatory / AURA
"We utilized the powerful mid-infrared capabilities of the Gemini telescope to record the impact's effect on Jupiter's upper atmosphere," said Imke de Pater from the University of California, Berkeley. "At these wavelengths we receive thermal radiation (heat) from the planet's upper atmosphere. The impact site is clearly much warmer than its surroundings, as shown by our image taken at an infrared wavelength of 18 microns."
As Universe Today reported earlier, this new spot on Jupiter was first seen by Australian amateur astronomer Anthony Wesley on July 19th. This set off a flurry of activity as the large ground based observatories have imaged Jupiter in attempt to learn more about the impact and the object that struck Jupiter. Astronomers now say the object was likely a small comet or asteroid, just a few hundreds of meters in diameter. Such small bodies are nearly impossible to detect near or beyond Jupiter unless they reveal cometary activity, or, as in this case, make their presence known by impacting a giant planet.
In infrared, the impact site shows up in remarkable detail. "The structure of the impact site is eerily reminiscent of the larger Shoemaker-Levy 9 sites 15 years ago," remarked Heidi Hammel (Space Science Institute), who was part of the team that supported the effort at Gemini. In 1994, Hammel led the Hubble Space Telescope team that imaged Jupiter when it was pummeled by a shattered comet. "The morphology is suggestive of an arc-like structure in the feature's debris field," Hammel noted.
The Gemini images were obtained with the MICHELLE spectrograph/imager, yielding a series of images at 7 different mid-infrared wavelengths. Two of the images (8.7 and 9.7 microns) were combined into a color composite image by Travis Rector at the University of Alaska, Anchorage to create the final false-color image. By using the full set of Gemini images taken over a range of wavelengths from 8 to 18 microns, the team will be able to disentangle the effects of temperature, ammonia abundance, and upper atmospheric aerosol content. Comparing these Gemini observations with past and future images will permit the team to study the evolution of features as Jupiter's strong winds disperse them.
"The Gemini support staff made a heroic effort to get these data," said de Pater. "We were on the telescope observing within 24 hours of contacting the observatory." Because of the transient nature of this event, the telescope was scheduled as a "Target of Opportunity" and required staff to react quickly to the request."
Comment: Have you read Stephen Hawking: Space debris represents biggest natural threat to humanity?
Casey Kazan & Rebecca Sato
dailygalaxy.com
Fri, 26 Jun 2009 21:13 UTC
© Space Telescope Science Institute
Something wicked this way comes
Something wicked this way comes
It is thought the collision of a rather smaller body with the Earth, about 70 million years ago, was responsible for the extinction of the dinosaurs. A few small early mammals survived, but anything as large as a human, would have almost certainly been wiped out.
Through Earth's history such collisions occur, on the average every one million year. If this figure is correct, it would mean that intelligent life on Earth has developed only because of the lucky chance that there have been no major collisions in the last 70 million years. Other planets in the galaxy, Hawking believes, on which life has developed, may not have had a long enough collision free period to evolve intelligent beings.
"The threat of the Earth being hit by an asteroid is increasingly being accepted as the single greatest natural disaster hazard faced by humanity," according to Nick Bailey of the University of Southampton's School of Engineering Sciences team, who has developed a threat identifying program.
The team used raw data from multiple impact simulations to rank each country based on the number of times and how severely they would be affected by each impact. The software, called NEOimpactor (from NASA's "NEO" or Near Earth Object program), has been specifically developed for measuring the impact of 'small' asteroids under one kilometer in diameter.
Early results indicate that in terms of population lost, China, Indonesia, India, Japan and the United States face the greatest overall threat; while the United States, China, Sweden, Canada and Japan face the most severe economic effects due to the infrastructure destroyed.
The top ten countries most at risk are China, Indonesia, India, Japan, the United States, the Philippines, Italy, the United Kingdom, Brazil and Nigeria.
"The consequences for human populations and infrastructure as a result of an impact are enormous," says Bailey. "Nearly one hundred years ago a remote region near the Tunguska River witnessed the largest asteroid impact event in living memory when a relatively small object (approximately 50 meters in diameter) exploded in mid-air. While it only flattened unpopulated forest, had it exploded over London it could have devastated everything within the M25. Our results highlight those countries that face the greatest risk from this most global of natural hazards and thus indicate which nations need to be involved in mitigating the threat."
What would happen to the human species and life on Earth in general if an asteroid the size of the one that created the famous K/T Event of 65 million years ago at the end of the Mesozoic Era that resulted in the extinction of the dinosaurs impacted our planet.
As Stephen Hawking says, the general consensus is that any comet or asteroid greater than 20 kilometers in diameter that strikes the Earth will result in the complete annihilation of complex life - animals and higher plants. (The asteroid Vesta, for example, one of the destinations of the Dawn Mission, is the size of Arizona).
How many times in our galaxy alone has life finally evolved to the equivalent of our plants and animals on some far distant planet, only to be utterly destroyed by an impact? Galactic history suggests it might be a common occurrence.
The first thing to understand about the KT event is that it was absolutely enormous: an asteroid (or comet) six to 10 miles in diameter streaked through the Earth's atmosphere at 25,000 miles an hour and struck the Yucatan region of Mexico with the force of 100 megatons - the equivalent of one Hiroshima bomb for every person alive on Earth today. Not a pretty scenario!
Recent calculations show that our planet would go into another "Snowball Earth" event like the one that occurred 600 million years ago, when it is believed the oceans froze over (although some scientists dispute this hypothesis -see link below).
While microbial bacteria might readily survive such calamitous impacts, our new understanding from the record of the Earth's mass extinctions clearly shows that plants and animals are very susceptible to extinction in the wake of an impact.
Impact rates depend on how many comets and asteroids exist in a particular planetary system. In general there is one major impact every million years - a mere blink of the eye in geological time. It also depends on how often those objects are perturbed from safe orbits that parallel the Earth's orbit to new, Earth-crossing orbits that might, sooner or later, result in a catastrophic K/T or Permian-type mass extinction.
The asteroid that hit Vredefort located in the Free State Province of South Africa is one of the largest to ever impact Earth, estimated at over 10 km (6 miles) wide, although it is believed by many that the original size of the impact structure could have been 250 km in diameter, or possibly larger (though the Wilkes Land crater in Antarctica, if confirmed to have been the result of an impact event, is even larger at 500 kilometers across). The town of Vredefort is situated in the crater (image).
Dating back 2,023 million years, it is the oldest astrobleme found on earth so far, with a radius of 190km, it is also the most deeply eroded. Vredefort Dome Vredefort bears witness to the world's greatest known single energy release event, which caused devastating global change, including, according to many scientists, major evolutionary changes.
What has kept the Earth "safe" at least the past 65 million years, other than blind luck is the massive gravitational field of Jupiter, our cosmic guardian, with its stable circular orbit far from the sun, which assures a low number of impacts resulting in mass extinctions by sweeping up and scatters away most of the dangerous Earth-orbit-crossing comets and asteroids
Comment:
David Burghardt
RIA Novosti
Fri, 24 Jul 2009 02:45 UTC
© Unknown
Four professors from the University of Bologna, Carlo Stanghellini, Maurizio Serrazanetti, Romano Serra, and Marco Cocchi, believe Lake Cheko was created by a meteorite impact due to its shape and tree growth in the area. The lake is elliptical (approximately 100 meters by 300 meters) rather than round, which is consistent with other lakes and swamps in the area. However, no impact ring or rim residue has been discovered at the lake, which would be noticeable had a meteorite created the lake. The native Evenki say that the lake has always been there and the name comes from the Evenki language meaning "dark waters."
Four professors from the University of Bologna, Carlo Stanghellini, Maurizio Serrazanetti, Romano Serra, and Marco Cocchi, believe Lake Cheko was created by a meteorite impact due to its shape and tree growth in the area. The lake is elliptical (approximately 100 meters by 300 meters) rather than round, which is consistent with other lakes and swamps in the area. However, no impact ring or rim residue has been discovered at the lake, which would be noticeable had a meteorite created the lake. The native Evenki say that the lake has always been there and the name comes from the Evenki language meaning "dark waters."
On June 30, 1908, Eastern Siberia was hit by an explosion equal to 2,000 times the nuclear bomb that destroyed the Japanese city of Hiroshima in 1945, destroying 2,200 square kilometers of taiga and flattening tens of millions of trees. If this impact had occurred four hours later, the city of St. Petersburg and other nearby villages would have been wiped off the face of the earth.
Travel to epicenter
Some 15 hours after the devastating impact, the skies throughout Europe were lit up for several nights and white nights were noted in places that had never experienced such a phenomenon. Witnesses at the time in Britain, Denmark and Germany said they were able to read a newspaper in the middle of the night without using any artificial light.
It was not until the winter of 1927-1928 that the first expedition was organized to investigate reports from witnesses of the event. The expedition was led by Russian scientist Leonid Kulik, who headed for the epicenter in search for the meteorite he believed was the only possible explanation for the event.
Travel back then to such a remote area was a very expensive and grueling affair, taking first a train to Krasnoyarsk in Eastern Siberia, and then traveling north on foot for hundreds of kilometers. Kulik's first expedition 19 years after the event enlisted numerous native Evenki guides and dozens of reindeer. Kulik, like hundreds of scientists after him, found no traces of a meteorite.
Travel to the area today is much easier than in Kulik's time, taking an airplane from Moscow to Krasnoyarsk, then a small prop plane to the village of Vanavara, and finally a Russian Mi-8 cargo helicopter into the region of the epicenter.
The two-week expedition included six professors from the University of Bologna, the University of Florence, and Cornell University.
There are some 100 theories of the Tunguska Event, including some of the more bizarre ones of a UFO crash site, a WWII bomber caught in a time warp and returning to 1908, Earth crossing through a black hole, and a cloud of mosquitoes that spontaneously combusted due to heat created by flying too densely.
The first theory was created in 1908 by native Evenki tribes in Eastern Siberia who were the actual witnesses of the event. According to their legend, the fire god, Agdy, became angered and destroyed all that was living in the area. Witnesses said there were several deafening explosions and trees were heard falling thousands of miles away.
The researchers looked at two of the most probable theories: meteorite impact and volcanic gas vent explosion. The scientific expedition was divided into two camps, one at Lake Cheko, where they were researching the meteorite theory, and the other at Kulik's Cabin near the epicenter (some 10 kilometers from the first group), where they were researching geological explanations for the blast.
Meteorite Impact Theory (Lake Cheko)
Of the hundreds of expeditions into the epicenter or impact area, not one has found any evidence that a meteorite struck the Earth's surface. Pieces of a meteorite have never been discovered and no crater has been confirmed anywhere in the area.
Four professors from the University of Bologna, Carlo Stanghellini, Maurizio Serrazanetti, Romano Serra, and Marco Cocchi, believe Lake Cheko was created by a meteorite impact due to its shape and tree growth in the area. The lake is elliptical (approximately 100 meters by 300 meters) rather than round, which is consistent with other lakes and swamps in the area.
However, no impact ring or rim residue has been discovered at the lake, which would be noticeable had a meteorite created the lake. The native Evenki say that the lake has always been there and the name comes from the Evenki language meaning "dark waters."
Professors Stanghellini and Serrazanetti focused their research on the lake bottom using both technical and not so technical equipment, including a magnetometer, radar, underwater camera and grappling hooks.
The scientists used a magnetometer to locate magnetic elements on the floor of the lake such as iron or other metallic elements, which would indicate that a meteorite or its fragments were on the bottom. Stanghellini described a magnetometer as a sophisticated compass that will show peaks on a monitor if it finds something metal.
He said that just like a regular compass, if you set a piece of metal near it, the arrow will point to the metal piece and not to the magnetic North. Because of the magnetometer's sensitivity, the scientists did their research on an inflatable rubber raft using wooden oars so as not spike the instrument. Before the process, they flagged
the entire lake in 10-meter swaths. They discovered a small anomaly in the center of the lake on one of the passes and said they would study the data more thoroughly on their return to Italy. On the following day, however, the magnetic anomaly was not detected on the screen and the scientists did not collect any other substantial evidence to support their theory that there are meteorite fragments on the bottom of the lake.
They also conducted radar soundings and underwater filming, but again came up with no substantial evidence.
Grappling hooks were dragged along the lake bottom to recover debris. They recovered mostly small branches and roots, which may or may not have been from 1908. The scientists said that the debris could have been under a thick layer of silt that would have preserved the debris, though they may have been recently deposited by the stream flowing into the lake. These samples were packed and sent to the university to define their age and find any proof of impact damage to them.
Stanghellini said further research of the lake's bottom was necessary, especially in drilling a core sample beneath the lake, though this would require international support and financing.
On shore, professors Serra and Cocchi cut down several trees and collected slabs as well as core samples of trees that survived the 1908 event, trees that were destroyed after the event and younger trees that appeared after the event. Samples were taken on the North and South side of Lake Cheko.
According to their preliminary studies, the samples showed that the trees had tight rings prior to the 1908 event, which means the trees grew very slowly due to competition with other trees and were growing densely together. Serra said that in 1908, the trees show scars with resin deposits (pitch) and then a very slow growth rate for two years due to shock. After 1910, the trees show much wider rings, which indicate there was less competition with other trees, more sunlight and nutrients.
He also said that the coniferous trees in the area should be associated with trees from the taiga and not lakeside forests, where there is usually heavy underbrush. Serra said that tree samples taken 4-50 meters from the lake are similar in growth patterns of trees 2-3 kilometers away from the lake prior to 1908, indicating that all of the trees are native to a taiga environment and not a lake.
He added that a significant growth change occurred in the trees located by the lake after 1908; whereas, those trees kilometers away from the lake continued to have tight rings due to slow growth and competition.
Serra noted that the survivor trees were much smaller during the 1908 event, meaning that they were bent over or twisted during the impact. All of the large trees, on the other hand, were uprooted. He said this is similar to what happens to trees during a hurricane. He also noted that the tree samples taken near Lake Cheko were similar to those taken after the Chernobyl nuclear reactor meltdown site in Ukraine in 1986.
Evidence collected in previous expeditions by Serra showed that tree limbs from 1908 contained deposits of magnesium, titanium, sulfurs, and several undefined elements, which would support the theories of a meteorite or even volcanic activity.
All four of the Italian researchers at Lake Cheko believe the lake was created by one of three impacts in 1908: the first exploded in the atmosphere, the second struck the ground, creating Lake Cheko and changing the direction of the creek, and the third struck the ground further North at the epicenter, presumably creating several deep bogs. They agreed that the meteorite that created the lake would have been 1-5 meters in diameter and the tree growth around the lake proved that it was created in 1908.
Cocchi did much research on an old creek bed that the scientists assume was cut off or rerouted after the 1908 event. Difficulties in researching the creek bed arise due to the fact that 20 centimeters under the surface there is permafrost that cannot be dug up. Drilling the creek bed is also planned to get a core sample in order to estimate when the creek changed its course and began flowing into the lake after it was created by the meteorite, according to the scientists.
Volcanic Gas Vent Explosion Theory (Tunguska Epicenter)
Jason Phipps Morgan, a geophysicist from Cornell University, and Paola Vanucchi, a geologist and geophysicist from the University of Florence, believe that the 1908 event was the result of a gas vent explosion created from the center of the earth. They did much investigation around the epicenter, especially what is called John's Rock, which is a 10-12 ton rock formation that is free-standing.
According to Morgan, this rock was actually "burped up" when the gas vent exploded, pushing the rock to the surface through a funnel. Morgan named the still unconfirmed funnel after his colleague, Paola's Funnel. He noted that this rock is the only one of its kind in the area and is definitely of volcanic nature. The scientists collected some 30 kilograms of rock samples, especially quartz and quartzite, from and around John's Rock, in search of shocked quartz, which would indicate that there was volcanic activity in the area.
Vanucchi said that some of the rock samples showed traces of being shocked, or fractured, and further research on the samples would be completed in both Italy and the United States. She also said that they believe they have found the main vent of the volcanic gas explosion very near to John's Rock.
The researchers revealed that the Russian geological mineral map they were supplied with was incorrect in many places in regard to the elements found in the area, as well as to the depth of some of the quartz deposits. Vanucchi said that they had started updating the existing map, but further research would be needed to perfect it.
The scientists were also interested in Churgym Waterfall which showed one of the largest samples of volcanic basalt in the world, indicating millions of years of volcanic activity in the area. There was a constant flow of lava, which is visible in layers around the falls and stream. Only some 30 meters of the basalt is above the surface, which is visible due to erosion by the stream and there is no estimate of how deep the volcanic rock extends beneath the earth.
Morgan said the amount of basalt in the area is so great that it proves the existence of constant volcanic activity for millions of years. Samples from the waterfall area were also taken for comparison with those from the John's Rock location. Though lava has ceased to reach the surface, lava vents still exist and can build up pressure and blow, thus creating a blast like that in the epicenter.
Comet Theory
One of the most commonly acceptable theories today is that of a comet or a piece from the tail of a comet hitting the Earth's surface. Upon returning to Moscow, RIA Novosti spoke with two Russian scientists on the comet theory.
Vitaly Romeiko, the director of the Department of Astrophysics at Zvenigorod Observatory, said in an interview in Moscow that the 1908 event was caused by a fragment of the Encke Comet's tail that entered the Earth's atmosphere as a ball of ice with small interplanetary fragments (dust particles) and, upon entrance, exploded due to the negative ions in the comet and the positive ions found on Earth. He pointed out that the Encke Comet also revolves around the sun and comes near Earth every 3.3 years.
Romeiko has participated in 23 expeditions into the Tunguska region.
Olga Gladysheva, a senior fellow at the A.F. Ioffe Physics and Technical Institute in St. Petersburg, supported Romeiko's theory in a separate interview with RIA Novosti, adding that the part of the comet's tail separated and created a giant ice ball that was created in a vacuum, and, therefore, made several explosions as the particles inside expanded and the ball disintegrated.
The Russian scientists base their theory on the fact on the absence of any meteorite material in the area, no rock fragments, or no impact areas that would create a crater.
Gladysheva said part of the comet's tail entered the Earth's ionosphere at more than 80 kilometers above ground, which is an intense area of atmospheric electricity. She said a major blast occurred over the epicenter at an altitude of 7-10 kilometers above the Earth's surface. The significance of the blast was due to the overly charged ions and differences in the positive and negative poles in the comet and Earth.
Romeiko said the ice ball that formed around the comet's dust particles before striking Earth would explain the absence of a crater or meteorite particles. The particles from the comet would be very minute and could most likely be found in the lower layers of peat moss in the area, which is frozen in permafrost.
101 Years Of An Unsolved Mystery
In separate conversations with the researchers during the expedition into the Tunguska epicenter, they all shared the same idea that the mystery will never be solved because scientists with their own theories and hypotheses will never agree on one single explanation. In regard to this, Romeiko said: "No one will back down on a theory that he has defended his entire life because that would mean failure."
Although the researchers returned without any substantial explanations for the event, they plan on returning to Tunguska to continue their research and prove their theories. Serra said there would be interest in the Tunguska Event far into the future, because the best scientists from around the world have been there and no one has come up with an explanation, which scientists simply cannot accept.
When the Italian and American research group left the epicenter, a new group of Russian "scientists" arrived. One of the group members said that she had worked with a psychic to identify which swamp a UFO had collided into in 1908.
Upon returning to the town of Vanavara, some 65 kilometers to the South of the epicenter, the Tunguska Reserve director, Ludmila Logunova, said that they know where the meteorite is located, but if they reveal its location, people would stop visiting the region.
Comment: For an in-depth review, read Tunguska, Psychopathy and the Sixth Extinction.
Dr Emily Baldwin
Astronomy Now
Tue, 21 Jul 2009 17:05 UTC
The Solar System is breaking out in spots. First Jupiter took a smack from a passing asteroid or comet, manifesting as a dark scar in the Jovian atmosphere, and now Venus is sporting a brilliant white spot in its southern polar region.
In an alert to fellow amateur astronomers, Venus observer Frank Melillo reports on his images captured on 19 July: "I have seen bright spots before but this one is an exceptional bright and quite intense area."
He suggests that it could be explained as an atmospheric effect, but could it be a sign of volcanic activity at the planet's surface? Venus is covered in a thick cloak of clouds which prevents any visible observation of the surface. Instead, radar is used to map the surface, but volcanic activity has never been observed directly.
"A volcanic eruption would be nice, but let's wait and find out!" says Venus specialist Dr Sanjay Limaye of the University of Wisconsin. "An eruption would have to be quite energetic to get a cloud this high." Furthermore, at a latitude of 50 degrees south, the spot lies outside the region of known volcanoes on Venus.
Melillo comments that the spot will not be seen again as intense as it is now, thanks to the rapid rotation of the planet's atmosphere. "I hope that someone will image Venus on Thursday when this part of the atmosphere is facing us again," he says.
Further observations will help shed light on the genesis of the bright spot and how it evolves as the atmosphere churns over.
Comment: Volcanic eruptions? Somebody knows what's really going on . . .
Military Hush-Up: Incoming Space Rocks Now Classified
Nothing to see here folks, please move along . . .
Flashback:
Dramatic Fireball over Southern Arizona
Robert Roy Britt
LiveScience
Fri, 26 Jun 2009 13:28 UTC
A bright fireball was spotted by several observers Tuesday, June 23
over Tucson and other parts of southern Arizona. It was a space rock
that broke apart dramatically as it streaked into Earth's atmosphere -
a "shooting star" on steroids. Such
events are not uncommon, but most are not seen because they occur over
the oceans, or late at night when few people are watching, or during
the day when they are not visible.
One observer compared it to a memorable 1992 event known as the Peekskill Fireball.
The Arizona fireball "looked very similar to the Peekskill one," writes Carl Hergenrother on the Transient Sky blog. "The colors are a close match with the head of the main fireball and pieces a brilliant blue-green while the long tails appeared reddish. Birth fireballs also produced many fragments which broke off the main body and quickly fell behind."
A "series of loud sonic booms heard from Tucson southward," Hergenrother writes, based on the accounts of others. He does not think the Arizona fireball lasted as long as the Peekskill event, however.
The Peekskill fireball was recorded by many observers along the East Coast of the United States - some of whom were out with their video cameras watching football games - around 7:50 pm, on Friday, Oct. 9, 1992. Check it out:
One observer compared it to a memorable 1992 event known as the Peekskill Fireball.
The Arizona fireball "looked very similar to the Peekskill one," writes Carl Hergenrother on the Transient Sky blog. "The colors are a close match with the head of the main fireball and pieces a brilliant blue-green while the long tails appeared reddish. Birth fireballs also produced many fragments which broke off the main body and quickly fell behind."
A "series of loud sonic booms heard from Tucson southward," Hergenrother writes, based on the accounts of others. He does not think the Arizona fireball lasted as long as the Peekskill event, however.
The Peekskill fireball was recorded by many observers along the East Coast of the United States - some of whom were out with their video cameras watching football games - around 7:50 pm, on Friday, Oct. 9, 1992. Check it out:
Comment: From the Transient Sky blog:
From KOLD, Tucson's local CBS affiliate, a video of the fireball taken by a security camera in Marana (just north of Tucson). The video shows what appears to be 2 fainter pieces below and to the right of the main fireball. I believe those 2 fainter objects are just reflections caused by the optics of the camera and are not actually real. What is real is the main fireball appearing in 3 or more pieces right before it faded from view.
Cloudbait Observatory
Mon, 13 Jul 2009 16:57 UTC
This slow, bright fireball occurred at 2:28 AM MDT over central Colorado. I have not received any witness reports.
Data has been recovered from the following cameras:
* Cloudbait (details, video)
* Tom Ashcraft's camera in New Mexico.
The
image at left is from the Cloudbait camera. The meteor produced a long
trail, gradually brightening to about magnitude -10 (the Moon, seen at
the bottom, is about magnitude -11). Several small flares of light are
also seen along the path. The fireball lasted over 5.5 seconds.
Based on the camera data, I have determined that the meteor began over south central Colorado, and descended to the northeast, ending near northwest Colorado Springs. It reached its peak brightness at a height of about 50 km (31 miles) near Cripple Creek. I don't currently have sufficient camera data to determine the descent angle.
The fairly low altitude and low velocity (16 km/s) mean this fireball might have produced meteorites. However, the brightness profile is suggestive of a meteor which simply burned up.
This chart shows the light curve of the fireball, peaking around mag -10.
Data has been recovered from the following cameras:
* Cloudbait (details, video)
* Tom Ashcraft's camera in New Mexico.
© Cloudbait Observatory
Based on the camera data, I have determined that the meteor began over south central Colorado, and descended to the northeast, ending near northwest Colorado Springs. It reached its peak brightness at a height of about 50 km (31 miles) near Cripple Creek. I don't currently have sufficient camera data to determine the descent angle.
The fairly low altitude and low velocity (16 km/s) mean this fireball might have produced meteorites. However, the brightness profile is suggestive of a meteor which simply burned up.
© Cloudbait Observatory
Nathan Morley
Cyprus Mail
Sat, 25 Jul 2009 15:42 UTC
Four residents spotted a strange light zipping across the coast off
Paphos on Thursday night in the latest in a series of incidents of
unidentified objects in our skies.
The UFO was clearly seen by John Knowles, a research specialist with Mutual UFO Network, he told the Cyprus Mail the sighting took place near Coral Bay and is appealing for more witnesses.
It was heading towards Paphos just off the coast, slow moving and a very bright fireball, so there may very well have been other witnesses."
"We had been watching the crescent moon set in Coral Bay. In the darkened skies, as we looked out to sea, an unknown object flying in a north-south direction crossed the sky in front of us. Altitude was about 300 feet, speed about 200 mph or less.
"The object that appeared like a fireball, extremely bright red-orange in colour, it maintained the same altitude as it passed to the south in the direction of Paphos."
Knowles added the object, which he saw at around 20.55pm on Thursday, finally vanished from the sky without trace.
His account was backed up by his next door neighbours, who also witnessed the bizarre sight and rushed to the phone to alert him.
Annie Davidson of Tala said: "I was out walking my dog and I saw a brilliant ball of light traveling very slowly close to the coastline. It was clearly visible for a while and then disappeared. I have never seen anything like it before."
On Monday, several sightings of five bright red lights hovering in the night sky near Cape Greco were observed. According to witness accounts, the lights moved creating several different shapes for around 8 minutes before disappearing.
Some suggest that Chinese lanterns could to be the most likely culprit, as they are often released into the skies at weddings and parties.
Recently Cyprus has been flooded with UFO reports from all parts of the island; last month a pilot approaching the illegal Tymbou airport in the north reported being followed by what he described as a "bright object which resembled a big man or a big garbage bag".
The UFO followed the aircraft until it landed and then disappeared.
Pictures taken by a Worcester family show what they claim is a "fireball" streaking across the Worcester night sky.
The object which had "orange flames coming from its top and sides" was spotted in Worcester at 10.15pm on Thursday.
Rob Giles, aged 59, was driving his daughter and niece home when he looked up to see the bright object up above in the clear sky.
He said: "It just came right over the top of us heading towards the north east. I just stopped the car and got out. I was telling my daughter to take a photo."
Mr Giles' 24-year-old daughter Sharon managed to snap the fiery object, as did his niece Kate Skibinski, also of Holly Mount Road, Tolladine.
"It was totally bizarre. I'm not sure what it was," said the 27-year-old.
"It wasn't an aeroplane because they have flashing lights. It could have been a meteorite."
In another twist, when Miss Skibinski phoned her father in Bristol, he claimed a similar object had streaked across the city's sky at about 10.30pm the same evening.
The three, who were all sober at the time of the sighting, lost site of the 'fireball' in Warndon Villages.
Space expert Kevin Yates, space communications manager at the Government's Earth Object Information Centre, in Leicester, said it was likely the object was a meteorite.
"From past experience, these things can be no bigger than a grain of sand and still give a good show. They're spectacular and fascinating to watch," he said.
He said there had been no reports from the RAF radar net at Fylingdales about any large objects falling.
The UFO was clearly seen by John Knowles, a research specialist with Mutual UFO Network, he told the Cyprus Mail the sighting took place near Coral Bay and is appealing for more witnesses.
It was heading towards Paphos just off the coast, slow moving and a very bright fireball, so there may very well have been other witnesses."
"We had been watching the crescent moon set in Coral Bay. In the darkened skies, as we looked out to sea, an unknown object flying in a north-south direction crossed the sky in front of us. Altitude was about 300 feet, speed about 200 mph or less.
"The object that appeared like a fireball, extremely bright red-orange in colour, it maintained the same altitude as it passed to the south in the direction of Paphos."
Knowles added the object, which he saw at around 20.55pm on Thursday, finally vanished from the sky without trace.
His account was backed up by his next door neighbours, who also witnessed the bizarre sight and rushed to the phone to alert him.
Annie Davidson of Tala said: "I was out walking my dog and I saw a brilliant ball of light traveling very slowly close to the coastline. It was clearly visible for a while and then disappeared. I have never seen anything like it before."
On Monday, several sightings of five bright red lights hovering in the night sky near Cape Greco were observed. According to witness accounts, the lights moved creating several different shapes for around 8 minutes before disappearing.
Some suggest that Chinese lanterns could to be the most likely culprit, as they are often released into the skies at weddings and parties.
Recently Cyprus has been flooded with UFO reports from all parts of the island; last month a pilot approaching the illegal Tymbou airport in the north reported being followed by what he described as a "bright object which resembled a big man or a big garbage bag".
The UFO followed the aircraft until it landed and then disappeared.
Worcester News
Sat, 25 Jul 2009 16:41 UTC
© Unknown
Fireball: A photo of the mysterious fiery object.
Fireball: A photo of the mysterious fiery object.
The object which had "orange flames coming from its top and sides" was spotted in Worcester at 10.15pm on Thursday.
Rob Giles, aged 59, was driving his daughter and niece home when he looked up to see the bright object up above in the clear sky.
He said: "It just came right over the top of us heading towards the north east. I just stopped the car and got out. I was telling my daughter to take a photo."
Mr Giles' 24-year-old daughter Sharon managed to snap the fiery object, as did his niece Kate Skibinski, also of Holly Mount Road, Tolladine.
"It was totally bizarre. I'm not sure what it was," said the 27-year-old.
"It wasn't an aeroplane because they have flashing lights. It could have been a meteorite."
In another twist, when Miss Skibinski phoned her father in Bristol, he claimed a similar object had streaked across the city's sky at about 10.30pm the same evening.
The three, who were all sober at the time of the sighting, lost site of the 'fireball' in Warndon Villages.
Space expert Kevin Yates, space communications manager at the Government's Earth Object Information Centre, in Leicester, said it was likely the object was a meteorite.
"From past experience, these things can be no bigger than a grain of sand and still give a good show. They're spectacular and fascinating to watch," he said.
He said there had been no reports from the RAF radar net at Fylingdales about any large objects falling.
John Hayes
UFOINFO
Sat, 25 Jul 2009 20:44 UTC
Posted: July 25, 2009
Date: June 30 2009
Time: 12:00 midnight
Number of witnesses: 2
Number of objects: 1
Shape of objects: Circular.
Weather Conditions: Clear Skies, great night. Maybe some clouds to the west. Moon low in the sky, crescent.
Description: Started out as a glow in the distance towards the south. It looked like a plane head light coming towards us, It got brighter and brighter so I asked my mate, look at this what do you think, as we watched it turned into what looked like a fireball the shape of an hour glass, then it went out and became a dimly lit object in the sky. As I watched it looked as if the sun was lighting up the object, sort of a vague outline. More grey then glowing. As I watched I noticed a red light on what looked like one edge of the object. If it had an edge it looked like the lower right corner, as it did not resemble a circle at this time, more like a chunk of something.
But the light was very odd, as I continued to watch the object moved over head from 10 o'clock position to the 11 o'clock position I noticed that the light seemed to be moving. The object moved to the 12 o'clock position about 15 seconds had elapsed since first spotting it in the sky, as I watched the red light traveled around what looked like a very large circle. No sound was heard what so ever. The red light traveled counter clockwise around and around making a complete circle about every 5 seconds. Just then I noticed that it looked like on top of the object was a red glow, the bottom was perfectly dark, other then the red light. As I noticed the faint red pinkish glow at I what I consider the rear of the object a small object caught my eye. It looked like an amber from a hot fire. It did a few loops behind the object then disappeared from my sight.
It also had the red pinkish glow, the object traveled off into the distance and faded from view (North) it was not bright at all just sort of a glow from the top and the red light. It took about 30 to 40 seconds for the whole event to take place. My mate said it had a different shape then I stated but that's where its good to have 2 points of view.
I hope to get my mate to write in as well what she saw that night. Keep watching you never know what you might see! I have never seen anything like this in 35 years of sky watching, I am 45 now.
Comment: According to the interviewed scientists, meteorites are very usual and almost fun though data shows that it is a growing and dangerous phenomenon... damage control?
Contrary
to prevailing wisdom, Jupiter does not protect Earth from comet
strikes. In fact, Earth would suffer fewer impacts without the
influence of Jupiter's gravity, a new study says. It could have
implications for determining which solar systems are most hospitable to
life.
A 1994 study showed that replacing Jupiter with a much smaller planet like Uranus or Neptune would lead to 1000 times as many long-period comets hitting Earth. This led to speculation that complex life would have a hard time developing in solar systems without a Jupiter-like planet because of more intense bombardment by comets.
But a new study by Jonathan Horner and Barrie Jones of Open University in Milton Keynes, UK, shows that if there were no planet at all in Jupiter's orbit, Earth would actually be safer from impacts.
The contradictory results arise because Jupiter affects comets in two different, competing ways. Its gravity helps pull comets into the inner solar system, where they have a chance of hitting Earth, but can also clear away Earth-threatening comets by ejecting them from the solar system altogether, via a gravitational slingshot effect.
Tripled impacts
According to the new study, the worst scenario for Earth is when Jupiter is replaced by a planet with about the mass of Saturn. "[Such a planet] is fairly capable of putting things into an Earth-crossing orbit, but still has some difficulty ejecting them, so they will stay on an Earth-crossing orbit for a much longer time," Horner told New Scientist. The projected result was more than three times as many impacts as in the real solar system.
So both the new study and the one from 1994 suggest that a smaller planet in Jupiter's orbit would leave Earth worse off, although they disagree about how much worse.
That may be because they differ on the source of the comets they examine. Horner looked at objects coming from the Kuiper belt, a region just beyond Neptune's orbit where many dormant comets reside. The previous study, meanwhile, looked at the Oort cloud, a vast collection of dormant comets extending hundreds of times further from the Sun.
Ultimately, knowing what kinds of solar systems are safest from bombardment could help in the search for alien life. But, despite the latest work, it is still unclear where we should be looking.
Asteroid threat
Alessandro Morbidelli of Nice Observatory in France, who studies solar system dynamics, says neither Horner's analyis nor the earlier study included the most important source of impacts - the asteroid belt. About 95% of the impacts on Earth are due to asteroids, he says.
He suspects that a smaller planet in place of Jupiter may lead to fewer asteroid impacts. "Given that near-Earth asteroids dominate the impact rate, decreasing asteroid impacts might cause a decrease in the overall bombardment rate of the Earth," he told New Scientist.
Horner and Jones plan to extend their study to include asteroids, but Morbidelli says there are even more factors to examine. "You can imagine solar systems where a much more massive and broader asteroid belt is preserved - it would be difficult to live in that solar system," he says. "You can imagine giant planets migrating and destroying an asteroid belt. There are so many factors it is difficult to handle them all."
The results were presented Friday at the European Planetary Science Congress 2007 in Potsdam, Germany.
Comment: Regarding the claim that Jupiter "protects us from an even more dangerous band of comets coming from the so-called Oort Cloud", let's see what Clube and Napier, British astronomers and writers of The Cosmic Serpent, have to say: The giant comets normally reside far beyond the planets, in a spherical cloud surrounding the Sun, called the Oort cloud. There is also evidence for a flattened disk of comets closer to the inner solar system, called the Edgeworth/Kuiper belt. What prompts members of either of these comet repositories to enter the realm of the planets? Clube and Napier suggest a galactic influence. The solar system periodically passes through the plane of the galaxy as the Sun (and the solar system with it) orbits the galactic center. Each passage may dislodge giant comets and divert them closer to the Sun. The outer planets, particularly Jupiter, may then perturb some of these giant comets into orbits which enter the inner solar system. These comets, stressed both by gravity and by heat from the sun, may fragment into a cloud of smaller objects with dynamically similar orbits.
Chiron offers a good example of a giant comet as called for by Clube and Napier's giant comet hypothesis. Chiron is somewhere between 148 and 208 kilometers in diameter. Currently Chiron's unstable "parking orbit" lies mostly between Saturn and Uranus. Chiron may end up injected into the inner solar system within a hundred thousand years, or ejected from the solar system on a similar time scale. It is also possible that Chiron has already visited the inner solar system.
The Taurid complex and the Kreutz sungrazer group are two families of objects which most likely represent the fragmented remains of two giant comets in the current era. SOHO has recently discovered many new members of the Kreutz group which were previously unknown.
The Kreutz progenitor was injected into a retrograde orbit and attained the sungrazing state at a high inclination to the ecliptic. Hence the debris of its "children" does not pose a threat to the Earth. The Taurid progenitor on the other hand ended up in a short-period low-inclination prograde orbit. This is why the Earth can encounter its debris with potentially calamitous results.
What would happen should the Earth pass through the orbit of a disintegrating giant comet just before or after the comet passes that same point? Since larger fragments tend to cluster close to the nucleus of the comet, chances would increase that the Earth would be bombarded by these larger fragments. The severity of this comet fragment shower would far exceed any ordinary meteor shower. Not only would "shooting stars" and bright fireballs caused by small debris appear, but so too would large airbursts and possibly ground impacts. These would result in significant destruction should they occur over an inhabited area. If a large enough fragment struck in the ocean -- say, 200 meters or so in diameter -- it would raise tsunamis even at a great distance that would sweep away coastal habitations.
Duncan Steel, a colleague of Clube and Napier, refers to this process as coherent catastrophism. Widespread destruction derives from the coherent arrival of many impactors within a few days, as opposed to the sporadic arrival of objects spread randomly in space. The shower repeats for a period of years until the cometary orbit precesses so that the Earth no longer encounters the dense part of the debris field. (Of course, sporadic debris unrelated to the disintegrating comet may impact at any time as well.)
Date: July 26, 2009
Residents of Xochitepec were treated to the sight of a "ball of fire" over Avenida Aeropuerto in the Miguel Hidalgo section of town. The witnesses fixed their eyes on a brilliant object in the sky for five minutes, before the sighting ended in a lightning-like flash and disappeared.
The unidentified object's presence drew the attention of many: some took out their camcorders, others photographed the "ball of fire" that seemed to fall very slowly from the heavens under clear skies.
Some claimed having heard a buzzing sound, stating unequivocally that it was not an airplane or anything known. Furthermore, its descent was slow and perpendicular. Several minutes into the sighting, people were shocked to see the object fire a bright light, resembling a beam or a bolt of lightning.
After this, the object commenced its slow ascent until it vanished from sight.
Whatever it was, it certainly captivated the locals. Some were astonished and others frightened; there were even those who spoke of the object as "an ill omen" signaling the arrival of plagues and diseases. They do not think that it was a meteorite, as these fall in seconds and are high in the sky -- but this object was at the same height as the clouds, of which there were none at the time.
The spectacle took place at 22:15 hours on Thursday, July 23 2009. The photos taken by a local resident were forwarded to this newsroom and are published here for everyone to draw their own conclusions.
Note from Prof. Ana Luisa Cid: According to eyewitness accounts, the alleged UFO fired a sort of beam, a situation that has been documented in other sightings, such as the Gabriel Hernandez case in Mexico City and the Bocovna UFO sighting in Chihuahua.
Source: El Sol de Cuernavaca
Date: June 30 2009
Time: 12:00 midnight
Number of witnesses: 2
Number of objects: 1
Shape of objects: Circular.
Weather Conditions: Clear Skies, great night. Maybe some clouds to the west. Moon low in the sky, crescent.
Description: Started out as a glow in the distance towards the south. It looked like a plane head light coming towards us, It got brighter and brighter so I asked my mate, look at this what do you think, as we watched it turned into what looked like a fireball the shape of an hour glass, then it went out and became a dimly lit object in the sky. As I watched it looked as if the sun was lighting up the object, sort of a vague outline. More grey then glowing. As I watched I noticed a red light on what looked like one edge of the object. If it had an edge it looked like the lower right corner, as it did not resemble a circle at this time, more like a chunk of something.
But the light was very odd, as I continued to watch the object moved over head from 10 o'clock position to the 11 o'clock position I noticed that the light seemed to be moving. The object moved to the 12 o'clock position about 15 seconds had elapsed since first spotting it in the sky, as I watched the red light traveled around what looked like a very large circle. No sound was heard what so ever. The red light traveled counter clockwise around and around making a complete circle about every 5 seconds. Just then I noticed that it looked like on top of the object was a red glow, the bottom was perfectly dark, other then the red light. As I noticed the faint red pinkish glow at I what I consider the rear of the object a small object caught my eye. It looked like an amber from a hot fire. It did a few loops behind the object then disappeared from my sight.
It also had the red pinkish glow, the object traveled off into the distance and faded from view (North) it was not bright at all just sort of a glow from the top and the red light. It took about 30 to 40 seconds for the whole event to take place. My mate said it had a different shape then I stated but that's where its good to have 2 points of view.
I hope to get my mate to write in as well what she saw that night. Keep watching you never know what you might see! I have never seen anything like this in 35 years of sky watching, I am 45 now.
P.Mz
La Dépêche
Wed, 22 Jul 2009 10:06 UTC
Yesterday, at 5.50 a.m. ... in Tarn-et-Garonne sky ... a bright trail of light.
Robert Sauby of Albefeuille Largade is not a compulsive liar, Even if, lately, people tend to look up at the sky, recalling the first steps of Armstrong on the moon...and perhaps seeing things that are not there. But we can trust the reports of Robert Sauby, who like other witnesses from Southwestern France, alerted the media. According to Sauby: "it was 5.50 a.m. I was driving towards Castelsarrasin. I was on the Tourron slope when I noticed a fireball... Actually, it was a long white trail preceding a very bright and intense white light. It lasted two or three seconds"...
The Perseids
According to scientists there is an explanation for this phenomenon. At Jolimont Observatory in Toulouse, a member of the astronomy society points out that we are about to enter the Perseids period... also called the "night of shooting stars". This phenomenon is the result of the entrance into the atmosphere of cometary debris that crosses the Earth trajectory every summer in its orbit around the Sun.
Probably a Meteorite
Pic du Midi Observatory astrophysicist, Joël Dolez, agrees, more or less: "it was probably a meteorite or chondrites".
Chondrites are a kind of stone meteorite composed of at least 35% metal. "This phenomenon, which occurs at a height of 20 or 30 km is easily visible from the surface of the globe. You can observe such phenomena every day. These space rocks usually disintegrate when entering the atmosphere." It is unlikely therefore that any fragments would be found on the ground. Concerning yesterday morning's sighting, Mr. Dolez also suggests the less likely possibility that it was an atmospheric phenomenon due to an electrically-charged fireball. Was it a meteorite? Was it an atmospheric phenomenon? Whatever the case, the witnesses were not dreaming yesterday morning; and, if in the coming days you look to the skies, you should see many similar sights.
[Translator's note: Tarn-et-Garonne, Castelsarrasin, Toulouse and Pic du Midi Observatory are located in Southwestern France.]
Robert Sauby of Albefeuille Largade is not a compulsive liar, Even if, lately, people tend to look up at the sky, recalling the first steps of Armstrong on the moon...and perhaps seeing things that are not there. But we can trust the reports of Robert Sauby, who like other witnesses from Southwestern France, alerted the media. According to Sauby: "it was 5.50 a.m. I was driving towards Castelsarrasin. I was on the Tourron slope when I noticed a fireball... Actually, it was a long white trail preceding a very bright and intense white light. It lasted two or three seconds"...
The Perseids
According to scientists there is an explanation for this phenomenon. At Jolimont Observatory in Toulouse, a member of the astronomy society points out that we are about to enter the Perseids period... also called the "night of shooting stars". This phenomenon is the result of the entrance into the atmosphere of cometary debris that crosses the Earth trajectory every summer in its orbit around the Sun.
Probably a Meteorite
Pic du Midi Observatory astrophysicist, Joël Dolez, agrees, more or less: "it was probably a meteorite or chondrites".
Chondrites are a kind of stone meteorite composed of at least 35% metal. "This phenomenon, which occurs at a height of 20 or 30 km is easily visible from the surface of the globe. You can observe such phenomena every day. These space rocks usually disintegrate when entering the atmosphere." It is unlikely therefore that any fragments would be found on the ground. Concerning yesterday morning's sighting, Mr. Dolez also suggests the less likely possibility that it was an atmospheric phenomenon due to an electrically-charged fireball. Was it a meteorite? Was it an atmospheric phenomenon? Whatever the case, the witnesses were not dreaming yesterday morning; and, if in the coming days you look to the skies, you should see many similar sights.
[Translator's note: Tarn-et-Garonne, Castelsarrasin, Toulouse and Pic du Midi Observatory are located in Southwestern France.]
Comment: According to the interviewed scientists, meteorites are very usual and almost fun though data shows that it is a growing and dangerous phenomenon... damage control?
David Shiga
New Scientist
Mon, 27 Aug 2007 06:47 UTC
© Julian Baum
Earth experienced an especially heavy bombardment of asteroids and comets early in the solar system's history.
Earth experienced an especially heavy bombardment of asteroids and comets early in the solar system's history.
A 1994 study showed that replacing Jupiter with a much smaller planet like Uranus or Neptune would lead to 1000 times as many long-period comets hitting Earth. This led to speculation that complex life would have a hard time developing in solar systems without a Jupiter-like planet because of more intense bombardment by comets.
But a new study by Jonathan Horner and Barrie Jones of Open University in Milton Keynes, UK, shows that if there were no planet at all in Jupiter's orbit, Earth would actually be safer from impacts.
The contradictory results arise because Jupiter affects comets in two different, competing ways. Its gravity helps pull comets into the inner solar system, where they have a chance of hitting Earth, but can also clear away Earth-threatening comets by ejecting them from the solar system altogether, via a gravitational slingshot effect.
Tripled impacts
According to the new study, the worst scenario for Earth is when Jupiter is replaced by a planet with about the mass of Saturn. "[Such a planet] is fairly capable of putting things into an Earth-crossing orbit, but still has some difficulty ejecting them, so they will stay on an Earth-crossing orbit for a much longer time," Horner told New Scientist. The projected result was more than three times as many impacts as in the real solar system.
So both the new study and the one from 1994 suggest that a smaller planet in Jupiter's orbit would leave Earth worse off, although they disagree about how much worse.
That may be because they differ on the source of the comets they examine. Horner looked at objects coming from the Kuiper belt, a region just beyond Neptune's orbit where many dormant comets reside. The previous study, meanwhile, looked at the Oort cloud, a vast collection of dormant comets extending hundreds of times further from the Sun.
Ultimately, knowing what kinds of solar systems are safest from bombardment could help in the search for alien life. But, despite the latest work, it is still unclear where we should be looking.
Asteroid threat
Alessandro Morbidelli of Nice Observatory in France, who studies solar system dynamics, says neither Horner's analyis nor the earlier study included the most important source of impacts - the asteroid belt. About 95% of the impacts on Earth are due to asteroids, he says.
He suspects that a smaller planet in place of Jupiter may lead to fewer asteroid impacts. "Given that near-Earth asteroids dominate the impact rate, decreasing asteroid impacts might cause a decrease in the overall bombardment rate of the Earth," he told New Scientist.
Horner and Jones plan to extend their study to include asteroids, but Morbidelli says there are even more factors to examine. "You can imagine solar systems where a much more massive and broader asteroid belt is preserved - it would be difficult to live in that solar system," he says. "You can imagine giant planets migrating and destroying an asteroid belt. There are so many factors it is difficult to handle them all."
The results were presented Friday at the European Planetary Science Congress 2007 in Potsdam, Germany.
Dennis Overbye
The New York Times
Sat, 25 Jul 2009 16:49 UTC
Jupiter took a bullet for us last weekend.
An object, probably a comet that nobody saw coming, plowed into the giant planet's colorful cloud tops sometime Sunday, splashing up debris and leaving a black eye the size of the Pacific Ocean. This was the second time in 15 years that this had happened. The whole world was watching when Comet Shoemaker-Levy 9 fell apart and its pieces crashed into Jupiter in 1994, leaving Earth-size marks that persisted up to a year.
That's Jupiter doing its cosmic job, astronomers like to say. Better it than us. Part of what makes the Earth such a nice place to live, the story goes, is that Jupiter's overbearing gravity acts as a gravitational shield deflecting incoming space junk, mainly comets, away from the inner solar system where it could do for us what an asteroid apparently did for the dinosaurs 65 million years ago. Indeed, astronomers look for similar configurations - a giant outer planet with room for smaller planets in closer to the home stars - in other planetary systems as an indication of their hospitableness to life.
Anthony Wesley, the Australian amateur astronomer who first noticed the mark on Jupiter and sounded the alarm on Sunday, paid homage to that notion when he told The Sydney Morning Herald, "If anything like that had hit the Earth it would have been curtains for us, so we can feel very happy that Jupiter is doing its vacuum-cleaner job and hoovering up all these large pieces before they come for us."
But is this warm and fuzzy image of the King of Planets as father-protector really true?
"I really question this idea," said Brian G. Marsden of the Harvard-Smithsonian Center for Astrophysics, referring to Jupiter as our guardian planet. As the former director of the International Astronomical Union's Central Bureau for Astronomical Telegrams, he has spent his career keeping track of wayward objects, particularly comets, in the solar system.
Jupiter is just as much a menace as a savior, he said. The big planet throws a lot of comets out of the solar system, but it also throws them in.
Take, for example, Comet Lexell, named after the Swedish astronomer Anders Lexell. In 1770 it whizzed only a million miles from the Earth, missing us by a cosmic whisker, Dr. Marsden said. That comet had come streaking in from the outer solar system three years earlier and passed close to Jupiter, which diverted it into a new orbit and straight toward Earth.
The comet made two passes around the Sun and in 1779 again passed very close to Jupiter, which then threw it back out of the solar system.
"It was as if Jupiter aimed at us and missed," said Dr. Marsden, who complained that the comet would never have come anywhere near the Earth if Jupiter hadn't thrown it at us in the first place.
Hal Levison, an astronomer at the Southwest Research Institute, in Boulder, Colo., who studies the evolution of the solar system, said that whether Jupiter was menace or protector depended on where the comets came from. Lexell, like Shoemaker Levy 9 and probably the truck that just hit Jupiter, most likely came from an icy zone of debris known as the Kuiper Belt, which lies just outside the orbit of Neptune, he explained. Jupiter probably does increase our exposure to those comets, he said.
But Jupiter helps protect us, he said, from an even more dangerous band of comets coming from the so-called Oort Cloud, a vast spherical deep-freeze surrounding the solar system as far as a light-year from the Sun. Every once in a while, in response to gravitational nudges from a passing star or gas cloud, a comet is unleashed from storage and comes crashing inward.
Jupiter's benign influence here comes in two forms. The cloud was initially populated in the early days of the solar system by the gravity of Uranus and Neptune sweeping up debris and flinging it outward, but Jupiter and Saturn are so strong, Dr. Levison said, that, first of all, they threw a lot of the junk out of the solar system altogether, lessening the size of this cosmic arsenal. Second, Jupiter deflects some of the comets that get dislodged and fall back in, Dr. Levison said.
"It's a double anti-whammy," he said.
Asteroids pose the greatest danger of all to Earth, however, astronomers say, and here Jupiter's influence is hardly assuring. Mostly asteroids live peacefully in the asteroid belt between Mars and Jupiter, whose gravity, so the standard story goes, keeps them too stirred to coalesce into a planet but can cause them to collide and rebound in the direction of Earth.
That's what happened, Greg Laughlin of the University of California at Santa Cruz, said, to a chunk of iron and nickel about 50 yards across roughly 10 million to 100 million years ago. The result is a hole in the desert almost a mile wide and 500 feet deep in northern Arizona, called Barringer Crater. A gift, perhaps, from our friend and lord, Jupiter.
An object, probably a comet that nobody saw coming, plowed into the giant planet's colorful cloud tops sometime Sunday, splashing up debris and leaving a black eye the size of the Pacific Ocean. This was the second time in 15 years that this had happened. The whole world was watching when Comet Shoemaker-Levy 9 fell apart and its pieces crashed into Jupiter in 1994, leaving Earth-size marks that persisted up to a year.
That's Jupiter doing its cosmic job, astronomers like to say. Better it than us. Part of what makes the Earth such a nice place to live, the story goes, is that Jupiter's overbearing gravity acts as a gravitational shield deflecting incoming space junk, mainly comets, away from the inner solar system where it could do for us what an asteroid apparently did for the dinosaurs 65 million years ago. Indeed, astronomers look for similar configurations - a giant outer planet with room for smaller planets in closer to the home stars - in other planetary systems as an indication of their hospitableness to life.
Anthony Wesley, the Australian amateur astronomer who first noticed the mark on Jupiter and sounded the alarm on Sunday, paid homage to that notion when he told The Sydney Morning Herald, "If anything like that had hit the Earth it would have been curtains for us, so we can feel very happy that Jupiter is doing its vacuum-cleaner job and hoovering up all these large pieces before they come for us."
But is this warm and fuzzy image of the King of Planets as father-protector really true?
"I really question this idea," said Brian G. Marsden of the Harvard-Smithsonian Center for Astrophysics, referring to Jupiter as our guardian planet. As the former director of the International Astronomical Union's Central Bureau for Astronomical Telegrams, he has spent his career keeping track of wayward objects, particularly comets, in the solar system.
Jupiter is just as much a menace as a savior, he said. The big planet throws a lot of comets out of the solar system, but it also throws them in.
Take, for example, Comet Lexell, named after the Swedish astronomer Anders Lexell. In 1770 it whizzed only a million miles from the Earth, missing us by a cosmic whisker, Dr. Marsden said. That comet had come streaking in from the outer solar system three years earlier and passed close to Jupiter, which diverted it into a new orbit and straight toward Earth.
The comet made two passes around the Sun and in 1779 again passed very close to Jupiter, which then threw it back out of the solar system.
"It was as if Jupiter aimed at us and missed," said Dr. Marsden, who complained that the comet would never have come anywhere near the Earth if Jupiter hadn't thrown it at us in the first place.
Hal Levison, an astronomer at the Southwest Research Institute, in Boulder, Colo., who studies the evolution of the solar system, said that whether Jupiter was menace or protector depended on where the comets came from. Lexell, like Shoemaker Levy 9 and probably the truck that just hit Jupiter, most likely came from an icy zone of debris known as the Kuiper Belt, which lies just outside the orbit of Neptune, he explained. Jupiter probably does increase our exposure to those comets, he said.
But Jupiter helps protect us, he said, from an even more dangerous band of comets coming from the so-called Oort Cloud, a vast spherical deep-freeze surrounding the solar system as far as a light-year from the Sun. Every once in a while, in response to gravitational nudges from a passing star or gas cloud, a comet is unleashed from storage and comes crashing inward.
Jupiter's benign influence here comes in two forms. The cloud was initially populated in the early days of the solar system by the gravity of Uranus and Neptune sweeping up debris and flinging it outward, but Jupiter and Saturn are so strong, Dr. Levison said, that, first of all, they threw a lot of the junk out of the solar system altogether, lessening the size of this cosmic arsenal. Second, Jupiter deflects some of the comets that get dislodged and fall back in, Dr. Levison said.
"It's a double anti-whammy," he said.
Asteroids pose the greatest danger of all to Earth, however, astronomers say, and here Jupiter's influence is hardly assuring. Mostly asteroids live peacefully in the asteroid belt between Mars and Jupiter, whose gravity, so the standard story goes, keeps them too stirred to coalesce into a planet but can cause them to collide and rebound in the direction of Earth.
That's what happened, Greg Laughlin of the University of California at Santa Cruz, said, to a chunk of iron and nickel about 50 yards across roughly 10 million to 100 million years ago. The result is a hole in the desert almost a mile wide and 500 feet deep in northern Arizona, called Barringer Crater. A gift, perhaps, from our friend and lord, Jupiter.
Comment: Regarding the claim that Jupiter "protects us from an even more dangerous band of comets coming from the so-called Oort Cloud", let's see what Clube and Napier, British astronomers and writers of The Cosmic Serpent, have to say: The giant comets normally reside far beyond the planets, in a spherical cloud surrounding the Sun, called the Oort cloud. There is also evidence for a flattened disk of comets closer to the inner solar system, called the Edgeworth/Kuiper belt. What prompts members of either of these comet repositories to enter the realm of the planets? Clube and Napier suggest a galactic influence. The solar system periodically passes through the plane of the galaxy as the Sun (and the solar system with it) orbits the galactic center. Each passage may dislodge giant comets and divert them closer to the Sun. The outer planets, particularly Jupiter, may then perturb some of these giant comets into orbits which enter the inner solar system. These comets, stressed both by gravity and by heat from the sun, may fragment into a cloud of smaller objects with dynamically similar orbits.
Chiron offers a good example of a giant comet as called for by Clube and Napier's giant comet hypothesis. Chiron is somewhere between 148 and 208 kilometers in diameter. Currently Chiron's unstable "parking orbit" lies mostly between Saturn and Uranus. Chiron may end up injected into the inner solar system within a hundred thousand years, or ejected from the solar system on a similar time scale. It is also possible that Chiron has already visited the inner solar system.
The Taurid complex and the Kreutz sungrazer group are two families of objects which most likely represent the fragmented remains of two giant comets in the current era. SOHO has recently discovered many new members of the Kreutz group which were previously unknown.
The Kreutz progenitor was injected into a retrograde orbit and attained the sungrazing state at a high inclination to the ecliptic. Hence the debris of its "children" does not pose a threat to the Earth. The Taurid progenitor on the other hand ended up in a short-period low-inclination prograde orbit. This is why the Earth can encounter its debris with potentially calamitous results.
What would happen should the Earth pass through the orbit of a disintegrating giant comet just before or after the comet passes that same point? Since larger fragments tend to cluster close to the nucleus of the comet, chances would increase that the Earth would be bombarded by these larger fragments. The severity of this comet fragment shower would far exceed any ordinary meteor shower. Not only would "shooting stars" and bright fireballs caused by small debris appear, but so too would large airbursts and possibly ground impacts. These would result in significant destruction should they occur over an inhabited area. If a large enough fragment struck in the ocean -- say, 200 meters or so in diameter -- it would raise tsunamis even at a great distance that would sweep away coastal habitations.
Duncan Steel, a colleague of Clube and Napier, refers to this process as coherent catastrophism. Widespread destruction derives from the coherent arrival of many impactors within a few days, as opposed to the sporadic arrival of objects spread randomly in space. The shower repeats for a period of years until the cometary orbit precesses so that the Earth no longer encounters the dense part of the debris field. (Of course, sporadic debris unrelated to the disintegrating comet may impact at any time as well.)
Inexplicata
Mon, 27 Jul 2009 15:23 UTC
© Unknown
Residents of Xochitepec were treated to the sight of a "ball of fire" over Avenida Aeropuerto in the Miguel Hidalgo section of town. The witnesses fixed their eyes on a brilliant object in the sky for five minutes, before the sighting ended in a lightning-like flash and disappeared.
The unidentified object's presence drew the attention of many: some took out their camcorders, others photographed the "ball of fire" that seemed to fall very slowly from the heavens under clear skies.
Some claimed having heard a buzzing sound, stating unequivocally that it was not an airplane or anything known. Furthermore, its descent was slow and perpendicular. Several minutes into the sighting, people were shocked to see the object fire a bright light, resembling a beam or a bolt of lightning.
After this, the object commenced its slow ascent until it vanished from sight.
Whatever it was, it certainly captivated the locals. Some were astonished and others frightened; there were even those who spoke of the object as "an ill omen" signaling the arrival of plagues and diseases. They do not think that it was a meteorite, as these fall in seconds and are high in the sky -- but this object was at the same height as the clouds, of which there were none at the time.
The spectacle took place at 22:15 hours on Thursday, July 23 2009. The photos taken by a local resident were forwarded to this newsroom and are published here for everyone to draw their own conclusions.
Note from Prof. Ana Luisa Cid: According to eyewitness accounts, the alleged UFO fired a sort of beam, a situation that has been documented in other sightings, such as the Gabriel Hernandez case in Mexico City and the Bocovna UFO sighting in Chihuahua.
Source: El Sol de Cuernavaca
Last night, dozens of witnesses reported seeing lights and hearing an
explosion as something crashed into the Ottawa River. Search-and-rescue
crews from Ottawa and Gatineau showed up but so far, haven't found
anything. Was it an airplane? According to the Ottawa Citizen newspaper, no planes are missing. Maybe it was a meteorite?
From the Ottawa Citizen:
From the Ottawa Citizen:
Dr. Dirk Keenan was sailing with some friends out of the Nepean Yacht Club when they saw the light of what looked like a small aircraft to the east, close to the Quebec shore.
"I noticed the light coming down. It was like a headlight, very bright," Keenan said Tuesday morning. "It descended very rapidly, levelled off, then disappeared."
Keenan, a student pilot himself, thought it looked like the pilot had lost control and gone into a dive, then briefly recovered before going down. Keenan steered his boat toward the position, but didn't dare get too close to the rapids in the dark. The lights appeared to vanish into the river or into the forest on the Quebec side.
UK UFO Sighting Reports
Tue, 28 Jul 2009 15:35 UTC
Posted: July 28, 2009
Date of Sighting: Saturday/Sunday 25th/26th July 2009
Time: 11.50pm-1.10am
Witness Statement: Saturday/Sunday 25th/26th July
After a night out we arrived back in Long Eaton & dropped my daughter at her house at about 11.50pm. She signaled to us to get out of the car and my wife & I looked to where she was pointing and saw about 4, what can only be described as fireballs traveling at a lowish altitude in a north easterly direction. They were followed by another 2. We watched them disappear from view and went to our house a couple of streets away. On the journey we saw at least 2 more of the objects. On arriving home, we got out our binoculars and after a time at about 12.15 another one came past over head. Then about 12.30 the final one? (We watched for about another 40 minutes but saw no others.)
Although there was a certain amount of breeze, the objects were flying faster than that. I don't know how big Chinese lanterns are, but these must have been the size of a hot air balloon and surely being aflame as they appeared to be, would have burned themselves out in a short space of time. There must have been lots of people who witnessed this, and although we are in close proximity to EM airport, I do not think it was aeroplanes or other normal flying craft. I would like to here what others make of it. In my excitement I never thought to use my mobile phone to capture the images. Sorry.
Icy
comets - not rocky asteroids - launched a dramatic assault on the Earth
and moon around 3.85 billion years ago, a new study of ancient rocks in
Greenland suggests. The work suggests much of Earth's water could have
been brought to the planet by comets.
"We can see craters on the moon's surface with the naked eye, but nobody actually knew what caused them - was it rocks, was it iron, was it ice?" says Uffe Gråe Jørgensen, an astronomer at the Niels Bohr Institute in Copenhagen, Denmark. "It's exciting to find signs that it was actually ice."
Evidence suggests that the Earth and moon had both formed around 4.5 billion years ago. But almost all the craters on the moon date to a later period, the "Late Heavy Bombardment" 3.8 to 3.9 billion years ago, when around 100 million billion tonnes of rock or ice crashed onto the lunar surface. The Earth would have been pummelled by debris at the same time, although plate tectonics on our restless planet have since erased the scars.
To find out whether asteroids or comets were the main culprits for the bombardment, Jørgensen decided to measure levels of the element iridium in ancient terrestrial rocks. Iridium is rare on the Earth's surface because almost all of it bound to iron and sank into the Earth's core soon after the planet had formed. But iridium is relatively common in comets and meteorites.
Rock or ice
His team calculated the amount of iridium that asteroids would leave on the Earth and moon compared to comets. Because comets have more volatile elements and higher impact speeds due to their more elongated orbits around the sun, they would create giant plumes on impact, allowing more iridium to escape into space than during asteroid impacts.
The team predicted that asteroid bombardment would leave iridium levels of 18,000 and 10,000 parts per trillion in rocks on the Earth and moon respectively, while the same figures for comet bombardment would be about 130 and 10.
Ancient moon rocks returned by NASA's Apollo missions have already confirmed that the lunar iridium levels are 10 parts per trillion or less. To find out the terrestrial value, Jørgensen's team sampled some of the world's oldest rocks from Greenland, aged 3.8 billion years, and asked a Japanese laboratory to assess their iridium levels more accurately than ever before. They contained iridium levels of 150 parts per trillion.
That strongly suggests comets, rather than asteroids, caused the violent bombardment.
Giant plumes
If so, Jørgensen's team calculates that around 3400 tonnes of icy comet material fell on each square metre of the Earth. About half the comet material would ricochet back into space in giant plumes, leaving behind roughly a billion cubic kilometres of cometary water in total.
That is a similar amount to that in the Earth's oceans today, although it is not clear whether there was already water on the planet due to chemical reactions on the early Earth (see Earth's water brewed at home, not in space).
Michael Mumma, a comet expert at NASA's Goddard Space Flight Center in Maryland who was not involved in the research, says the new report is interesting: "The paper is certain to stimulate lively debate."
Journal reference: Icarus
A
strange spot emerged on Venus last week, and astronomers are not sure
what caused it. They hope future observations will reveal whether
volcanic activity, turbulence in the planet's atmosphere, or charged
particles from the sun are to blame.
Amateur astronomer Frank Melillo of Holtsville, New York, first spotted the new feature, which is brighter than its surroundings at ultraviolet wavelengths, on the planet's southern hemisphere on 19 July. That same day, an amateur observer in Australia found a dark spot on Jupiter that had been caused by a meteoroid impact.
The Venus spot was confirmed by other observers, and images from Europe's Venus Express, the only spacecraft in orbit around the planet, later revealed that the spot had appeared at least four days before Melillo saw it.
Observations show that the spot had already spread out somewhat by the end of last week, and astronomers are awaiting more recent observations from Venus Express.
The spot is bright at ultraviolet wavelengths, which may argue against a meteoroid impact as a cause. That's because rocky bodies, with the exception of objects very rich in water ice, should cause an impact site to darken at ultraviolet wavelengths as it fills with debris that absorbs such light, says Sanjay Limaye of the University of Wisconsin-Madison and a member of the Venus Express team.
Powerful eruption?
Another possibility is that a gust of charged particles from the sun could have created the glow by energising a patch of the upper atmosphere. Alternatively, waves in the atmosphere, which trigger turbulence and are thought to carry material up and down, could have concentrated bright material to create the spot.
A volcanic eruption is another suspect. Venus boasts the most volcanoes of any planet in the solar system, and nearly 90% of its surface is covered by basaltic lava flows, although no 'smoking gun' has yet been found for current volcanic activity. But an eruption would have had to be very powerful to punch through a dense layer in Venus's atmosphere to create the spot some 65 to 70 kilometres above the planet's surface.
"It's fair to say something unusual happened on Venus. Unfortunately, we don't know what happened," Limaye told New Scientist.
Volcanic gases
Two spectrometers on board Venus Express might help reveal the culprit. One directly measures the spectrum of light emanating from the planet, while the other can measure trace constituents in the atmosphere by measuring how gases there absorb sunlight.
These instruments could reveal changes in the size distribution of particles in the atmosphere and higher concentrations of molecules, such as sulphur dioxide, that could suggest a volcanic eruption.
If a volcano is to blame, proving it will be difficult. Even if Venus Express finds higher-than-average levels of sulphur dioxide in the atmosphere, the observation could be explained by non-volcanic processes, cautions Limaye. Sunlight can break down sulphuric acid in Venus's clouds to create sulphur dioxide, which may not be evenly circulated in the planet's atmosphere.
Mystery world
This is not the first time astronomers have spotted bright features in Venus's atmosphere. Bright spots have been seen from Earth for decades, although they have not been clearly explained, Limaye says.
The most recent dramatic brightening occurred in January 2007, when areas in both the northern and southern hemispheres of the planet brightened. Because it is localised in a spot, this new feature looks different, but it is equally mysterious.
"This shows how much we don't know about Venus," Limaye says. In some ways, Venus is a simpler planet than Earth - it has no oceans and because of its nearly vertical spin axis, practically no seasons, he adds. But planetary scientists still do not understand what causes the planet's atmosphere to rotate 60 times faster than the planet itself.
Comment: These are possibilities, of course. One may want to consider this as well: Military Hush-Up: Incoming Space Rocks Now Classified
The Apollo 11 moon landing is not the only significant space anniversary that falls this week. It is also 15 years since fragments of the Shoemaker-Levy 9 comet smashed into Jupiter, in July 1994, giving astronomers a first-hand look at the devastation that follows such cosmic collisions.
With uncanny timing, a similar impact event seems to have happened again. On Sunday, an amateur astronomer named Anthony Wesley observed a strange black blob on the surface of Jupiter. When he alerted Nasa professionals, they confirmed that it indeed appears to have been caused by another impact event.
The resulting debris cloud has been reported as covering an area with roughly the same diameter as the Earth. Astronomers have told me today that the likely cause is the impact of a comet, or comet fragment, between 500m and 2km in diameter. It all raises a potentially terrifying question. What might have happened had such an object struck not Jupiter, but the Earth?
The good news is that the devastation would not have been quite as bad as it seems to have been on Jupiter. The mass of the gas giant is so much greater than that of the Earth, that when objects collide with it they do so at much faster speeds, releasing much more energy. So even though Jupiter is sporting an Earth-sized bruise, that doesn't mean that a similar impact would engulf the Earth entirely in debris.
It's also the case that such impact events are probably a lot more common on Jupiter than they are in our neck of the planetary woods. For a start, Jupiter is a much bigger target. And secondly, as Matthew Genge, of Imperial College, London, put it to me today, its vast gravity means it often;"soaks up" comets approaching the inner solar system from the Kuiper belt. This phenomenon, indeed, may actually have helped to make the Earth a more hospitable place for life -- though any benefits are double-edged, as Jupiter's gravity can also perturb the orbits of asteroids and fling them our way.
That, though, is where the good news ends. According to the UK's Near-Earth Object Taskforce report, asteroids 700m in diameter strike the Earth every 10,000 to 100,000 years, and would devastate an area the size of Virginia if they hit land. An ocean impact would cause a hemisphere-wide tsunami. Objects on the 1km to 2km scale would cause wider destruction, and also affect the climate through a "nuclear winter" effect. Still larger objects could cause a mass extinction -- as did the 10km-plus object that landed at Chicxulub, now in Mexico, 65 million years ago. Though some scientists dispute it, the prevailing consensus is that it's no coincidence that that's also the date for the Cretaceous-Tertiary mass extinction, and the demise of the dinosaurs.
If you want an idea of the effects any given asteroid or comet might have, the University of Arizona has an online calculator here. Just fill in your parameters and go.
The Jupiter impact should make it perfectly clear that, for all the fun that's been poked at Lembit Opik when he's raised the issue, near-Earth object defence is not a laughing matter. It's something the world needs to take extremely seriously -- as Opik says again today. We need to think creatively about how we might divert an asteroid or comet that is found to be on collision course with Earth. Simply blowing it up, as Bruce Willis and Co. did in Armageddon, will probably be the worst solution of all, creating a shower of fragments that would pepper us like Shoemaker-Levy 9 bombarded Jupiter. But there are other options worth trying, such as nudging it away from us with rockets, or even painting it to change its albedo, and hence its speed.
Technical fixes, however, will be only one element of a workable planetary defence plan. Professor Richard Crowther, who chairs the UN's working group on near-Earth objects, made an interesting point about this when I spoke to him this afternoon. If an asteroid is on collision course with, say, the UK, then nudging it away from Earth will first involve nudging it onto a collision course with other countries -- who might not like that prospect. We're going to need international agreement on the steps we would have to take to protect ourselves, as well as the technology to do so.
Comment: You can read of another witness to bright, white flashes in the sky here.
Date of Sighting: Saturday/Sunday 25th/26th July 2009
Time: 11.50pm-1.10am
Witness Statement: Saturday/Sunday 25th/26th July
After a night out we arrived back in Long Eaton & dropped my daughter at her house at about 11.50pm. She signaled to us to get out of the car and my wife & I looked to where she was pointing and saw about 4, what can only be described as fireballs traveling at a lowish altitude in a north easterly direction. They were followed by another 2. We watched them disappear from view and went to our house a couple of streets away. On the journey we saw at least 2 more of the objects. On arriving home, we got out our binoculars and after a time at about 12.15 another one came past over head. Then about 12.30 the final one? (We watched for about another 40 minutes but saw no others.)
Although there was a certain amount of breeze, the objects were flying faster than that. I don't know how big Chinese lanterns are, but these must have been the size of a hot air balloon and surely being aflame as they appeared to be, would have burned themselves out in a short space of time. There must have been lots of people who witnessed this, and although we are in close proximity to EM airport, I do not think it was aeroplanes or other normal flying craft. I would like to here what others make of it. In my excitement I never thought to use my mobile phone to capture the images. Sorry.
Hazel Muir
New Scientist
Tue, 28 Jul 2009 00:29 UTC
© NASA
A new study suggests comets gouged out the vast majority of craters on the moon.
A new study suggests comets gouged out the vast majority of craters on the moon.
"We can see craters on the moon's surface with the naked eye, but nobody actually knew what caused them - was it rocks, was it iron, was it ice?" says Uffe Gråe Jørgensen, an astronomer at the Niels Bohr Institute in Copenhagen, Denmark. "It's exciting to find signs that it was actually ice."
Evidence suggests that the Earth and moon had both formed around 4.5 billion years ago. But almost all the craters on the moon date to a later period, the "Late Heavy Bombardment" 3.8 to 3.9 billion years ago, when around 100 million billion tonnes of rock or ice crashed onto the lunar surface. The Earth would have been pummelled by debris at the same time, although plate tectonics on our restless planet have since erased the scars.
To find out whether asteroids or comets were the main culprits for the bombardment, Jørgensen decided to measure levels of the element iridium in ancient terrestrial rocks. Iridium is rare on the Earth's surface because almost all of it bound to iron and sank into the Earth's core soon after the planet had formed. But iridium is relatively common in comets and meteorites.
Rock or ice
His team calculated the amount of iridium that asteroids would leave on the Earth and moon compared to comets. Because comets have more volatile elements and higher impact speeds due to their more elongated orbits around the sun, they would create giant plumes on impact, allowing more iridium to escape into space than during asteroid impacts.
The team predicted that asteroid bombardment would leave iridium levels of 18,000 and 10,000 parts per trillion in rocks on the Earth and moon respectively, while the same figures for comet bombardment would be about 130 and 10.
Ancient moon rocks returned by NASA's Apollo missions have already confirmed that the lunar iridium levels are 10 parts per trillion or less. To find out the terrestrial value, Jørgensen's team sampled some of the world's oldest rocks from Greenland, aged 3.8 billion years, and asked a Japanese laboratory to assess their iridium levels more accurately than ever before. They contained iridium levels of 150 parts per trillion.
That strongly suggests comets, rather than asteroids, caused the violent bombardment.
Giant plumes
If so, Jørgensen's team calculates that around 3400 tonnes of icy comet material fell on each square metre of the Earth. About half the comet material would ricochet back into space in giant plumes, leaving behind roughly a billion cubic kilometres of cometary water in total.
That is a similar amount to that in the Earth's oceans today, although it is not clear whether there was already water on the planet due to chemical reactions on the early Earth (see Earth's water brewed at home, not in space).
Michael Mumma, a comet expert at NASA's Goddard Space Flight Center in Maryland who was not involved in the research, says the new report is interesting: "The paper is certain to stimulate lively debate."
Journal reference: Icarus
Rachel Courtland
New Scientist
Thu, 30 Jul 2009 16:14 UTC
© Melillo/Maxson/ESA/University of Wisconsin-Madison/ALPO
A new, bright spot in the clouds of Venus was found by amateur astronomer Frank Melillo on 19 July
A new, bright spot in the clouds of Venus was found by amateur astronomer Frank Melillo on 19 July
Amateur astronomer Frank Melillo of Holtsville, New York, first spotted the new feature, which is brighter than its surroundings at ultraviolet wavelengths, on the planet's southern hemisphere on 19 July. That same day, an amateur observer in Australia found a dark spot on Jupiter that had been caused by a meteoroid impact.
The Venus spot was confirmed by other observers, and images from Europe's Venus Express, the only spacecraft in orbit around the planet, later revealed that the spot had appeared at least four days before Melillo saw it.
Observations show that the spot had already spread out somewhat by the end of last week, and astronomers are awaiting more recent observations from Venus Express.
The spot is bright at ultraviolet wavelengths, which may argue against a meteoroid impact as a cause. That's because rocky bodies, with the exception of objects very rich in water ice, should cause an impact site to darken at ultraviolet wavelengths as it fills with debris that absorbs such light, says Sanjay Limaye of the University of Wisconsin-Madison and a member of the Venus Express team.
Powerful eruption?
Another possibility is that a gust of charged particles from the sun could have created the glow by energising a patch of the upper atmosphere. Alternatively, waves in the atmosphere, which trigger turbulence and are thought to carry material up and down, could have concentrated bright material to create the spot.
A volcanic eruption is another suspect. Venus boasts the most volcanoes of any planet in the solar system, and nearly 90% of its surface is covered by basaltic lava flows, although no 'smoking gun' has yet been found for current volcanic activity. But an eruption would have had to be very powerful to punch through a dense layer in Venus's atmosphere to create the spot some 65 to 70 kilometres above the planet's surface.
"It's fair to say something unusual happened on Venus. Unfortunately, we don't know what happened," Limaye told New Scientist.
Volcanic gases
Two spectrometers on board Venus Express might help reveal the culprit. One directly measures the spectrum of light emanating from the planet, while the other can measure trace constituents in the atmosphere by measuring how gases there absorb sunlight.
These instruments could reveal changes in the size distribution of particles in the atmosphere and higher concentrations of molecules, such as sulphur dioxide, that could suggest a volcanic eruption.
If a volcano is to blame, proving it will be difficult. Even if Venus Express finds higher-than-average levels of sulphur dioxide in the atmosphere, the observation could be explained by non-volcanic processes, cautions Limaye. Sunlight can break down sulphuric acid in Venus's clouds to create sulphur dioxide, which may not be evenly circulated in the planet's atmosphere.
Mystery world
This is not the first time astronomers have spotted bright features in Venus's atmosphere. Bright spots have been seen from Earth for decades, although they have not been clearly explained, Limaye says.
The most recent dramatic brightening occurred in January 2007, when areas in both the northern and southern hemispheres of the planet brightened. Because it is localised in a spot, this new feature looks different, but it is equally mysterious.
"This shows how much we don't know about Venus," Limaye says. In some ways, Venus is a simpler planet than Earth - it has no oceans and because of its nearly vertical spin axis, practically no seasons, he adds. But planetary scientists still do not understand what causes the planet's atmosphere to rotate 60 times faster than the planet itself.
Comment: These are possibilities, of course. One may want to consider this as well: Military Hush-Up: Incoming Space Rocks Now Classified
Times Online
Tue, 21 Jul 2009 07:33 UTC
© NASA
With uncanny timing, a similar impact event seems to have happened again. On Sunday, an amateur astronomer named Anthony Wesley observed a strange black blob on the surface of Jupiter. When he alerted Nasa professionals, they confirmed that it indeed appears to have been caused by another impact event.
The resulting debris cloud has been reported as covering an area with roughly the same diameter as the Earth. Astronomers have told me today that the likely cause is the impact of a comet, or comet fragment, between 500m and 2km in diameter. It all raises a potentially terrifying question. What might have happened had such an object struck not Jupiter, but the Earth?
The good news is that the devastation would not have been quite as bad as it seems to have been on Jupiter. The mass of the gas giant is so much greater than that of the Earth, that when objects collide with it they do so at much faster speeds, releasing much more energy. So even though Jupiter is sporting an Earth-sized bruise, that doesn't mean that a similar impact would engulf the Earth entirely in debris.
It's also the case that such impact events are probably a lot more common on Jupiter than they are in our neck of the planetary woods. For a start, Jupiter is a much bigger target. And secondly, as Matthew Genge, of Imperial College, London, put it to me today, its vast gravity means it often;"soaks up" comets approaching the inner solar system from the Kuiper belt. This phenomenon, indeed, may actually have helped to make the Earth a more hospitable place for life -- though any benefits are double-edged, as Jupiter's gravity can also perturb the orbits of asteroids and fling them our way.
That, though, is where the good news ends. According to the UK's Near-Earth Object Taskforce report, asteroids 700m in diameter strike the Earth every 10,000 to 100,000 years, and would devastate an area the size of Virginia if they hit land. An ocean impact would cause a hemisphere-wide tsunami. Objects on the 1km to 2km scale would cause wider destruction, and also affect the climate through a "nuclear winter" effect. Still larger objects could cause a mass extinction -- as did the 10km-plus object that landed at Chicxulub, now in Mexico, 65 million years ago. Though some scientists dispute it, the prevailing consensus is that it's no coincidence that that's also the date for the Cretaceous-Tertiary mass extinction, and the demise of the dinosaurs.
If you want an idea of the effects any given asteroid or comet might have, the University of Arizona has an online calculator here. Just fill in your parameters and go.
The Jupiter impact should make it perfectly clear that, for all the fun that's been poked at Lembit Opik when he's raised the issue, near-Earth object defence is not a laughing matter. It's something the world needs to take extremely seriously -- as Opik says again today. We need to think creatively about how we might divert an asteroid or comet that is found to be on collision course with Earth. Simply blowing it up, as Bruce Willis and Co. did in Armageddon, will probably be the worst solution of all, creating a shower of fragments that would pepper us like Shoemaker-Levy 9 bombarded Jupiter. But there are other options worth trying, such as nudging it away from us with rockets, or even painting it to change its albedo, and hence its speed.
Technical fixes, however, will be only one element of a workable planetary defence plan. Professor Richard Crowther, who chairs the UN's working group on near-Earth objects, made an interesting point about this when I spoke to him this afternoon. If an asteroid is on collision course with, say, the UK, then nudging it away from Earth will first involve nudging it onto a collision course with other countries -- who might not like that prospect. We're going to need international agreement on the steps we would have to take to protect ourselves, as well as the technology to do so.
UK UFO Sighting Reports
Thu, 30 Jul 2009 19:08 UTC
Posted: July 30, 2009
Location of Sighting: The Glen Palacefields Runcorn
Date of Sighting: 30th July 2009
Time: 12.00am
Witness Statement: 12:00AM 30th July 09. Left my house in the Glen Palacefields Runcorn with a friend to drop him off when entering my car a MASSIVE white flash lit up the sky and the carpark, looked like a powerful camera flash but NO NOISE. Both me and my friend commented as thinking someone was in the close or the police helicopter was overhead. When driving on the expressway again a massive flash over the Hallwood estate to my right above again no noise when only being about 500 yrds away from where it looked like it originated in the estate or above.
Took left exit for Castlefields then again Large flash but over Halton Brook estate to my left just over the tree's coming down the slipway to the bottom of Boston Avenue. Both commented no noise at any point and little to no cloud cover with large breaks and able to see starlight in between. When dropped of friend at lower Castlefields on Warrington road joked that he would be taken away before he got to his door. When reversing out of close rear end towards new flats near Peva garage Brightest flash about 400-600yrd behind me close to Runcorn castle. Called partner to inform of this persistent bright flash when again another flash over Halton Brook. Took same journey home checking the sky as you do in Runcorn but no flashes on this part traveling on the expressway. When got home took partner into back garden backing onto rural woods and advised of what we have just seen when again large white flash from the Hallwood - Halton Brook direction from the Glen Palacefields. On every occasion no noise no rumble no clap with little to no cloud cover and starlight between brakes 3 witnesses at 2 separate times and all confirming no noise but such close proximity that if was lightning there would have been a gap of light and thunder of less than 1 second and all coming from the area between the housing estates of Palacefields Hallwood Halton Brook and Castlefields, with the brightest being when stationary in the Glen and Castlefields. Any clues? I haven't.
Location of Sighting: The Glen Palacefields Runcorn
Date of Sighting: 30th July 2009
Time: 12.00am
Witness Statement: 12:00AM 30th July 09. Left my house in the Glen Palacefields Runcorn with a friend to drop him off when entering my car a MASSIVE white flash lit up the sky and the carpark, looked like a powerful camera flash but NO NOISE. Both me and my friend commented as thinking someone was in the close or the police helicopter was overhead. When driving on the expressway again a massive flash over the Hallwood estate to my right above again no noise when only being about 500 yrds away from where it looked like it originated in the estate or above.
Took left exit for Castlefields then again Large flash but over Halton Brook estate to my left just over the tree's coming down the slipway to the bottom of Boston Avenue. Both commented no noise at any point and little to no cloud cover with large breaks and able to see starlight in between. When dropped of friend at lower Castlefields on Warrington road joked that he would be taken away before he got to his door. When reversing out of close rear end towards new flats near Peva garage Brightest flash about 400-600yrd behind me close to Runcorn castle. Called partner to inform of this persistent bright flash when again another flash over Halton Brook. Took same journey home checking the sky as you do in Runcorn but no flashes on this part traveling on the expressway. When got home took partner into back garden backing onto rural woods and advised of what we have just seen when again large white flash from the Hallwood - Halton Brook direction from the Glen Palacefields. On every occasion no noise no rumble no clap with little to no cloud cover and starlight between brakes 3 witnesses at 2 separate times and all confirming no noise but such close proximity that if was lightning there would have been a gap of light and thunder of less than 1 second and all coming from the area between the housing estates of Palacefields Hallwood Halton Brook and Castlefields, with the brightest being when stationary in the Glen and Castlefields. Any clues? I haven't.
Comment: You can read of another witness to bright, white flashes in the sky here.
UK UFO Sightings
Thu, 30 Jul 2009 15:03 UTC
Posted: July 30, 2009
Location of Sighting: Blackpark Road, Whitchurch, Shropshire
Date of Sighting: Saturday 4th July 2009
Time: 11.20-11.30
Witness Statement: Whilst sitting in the hot tub, looking up at the stars, we both noticed a bright light, which looked similar to a large Chinese lantern, it sort of drifted across the sky in a northerly direction, it suddenly changed direction and headed south east and upwards quite quickly, the light appeared to be a ball of fire, and we watched it for about 4-5 minutes.
Approximately 10 minutes later, we spotted a much bigger fireball in the east, traveling northwards. This object was moving at some considerable speed, and disappeared behind the trees on the horizon. It resembled a large comet, but without a tail. Neither sighting was accompanied by any discernible sound. As we live on the very outskirts of town, we are able to get a good clear view of the night sky with very little distortion from street lighting.
Tracking
plumes from space shuttle launches provided researchers with one of the
strongest pieces of evidence that a comet crash was responsible for
flattening a Siberian forest in 1908.
The crash, which leveled trees for hundreds of miles in Siberia, was followed by the appearance of extremely bright clouds, visible by night.
Similar clouds triggered by the flights of space shuttles through atmosphere were found over the planet's poles two days after a launch from Florida, research published in last week's Geophysical Research Letters shows.
The creation of so-called noctilucent, or night-shining clouds from water vapor in shuttle rocket plumes buttresses the theory that the clouds spotted after the 1908 impact were triggered by similar atmospheric dynamics, with the water vapor coming from a comet, lead researcher Michael Kelley told Discovery News.
"The shuttles put 300 metric tons of water vapor at the same region that a comet would," said Kelley, a professor at Cornell University.
The cause of what has been referred to as the "Great Siberian Impact Event," or the "Tunguska Event," has been debated for decades. No meteorite remains have ever been found and the appearance of the mysterious night-shining clouds led many scientists to suspect a comet was responsible.
"It's kind of important that the world got hit by a comet, since Jupiter just got hit again," Kelley said.
Astronomers have been watching an Earth-sized gouge in Jupiter's atmosphere believed to be caused by a comet impact on July 19.
Noctilucent clouds, which form at the edge of space 62 to 68 miles above the planet, are about 10 million times brighter than ordinary clouds. They contain electrically charged ice.
"It's a very difficult region to access," said Clemson University's Miguel Larsen.
The shuttle plumes, which are laced with iron atoms and iron ions, provided researches with a way to track how water vapor is transported by winds and other dynamics of the upper atmosphere.
Noctilucent clouds, which have been increasing in appearance, also can serve to gauge if efforts to mitigate global climate changes are successful, Kelley added.
"It's thought that these clouds are like a miner's canary of global change," he said. "The atmosphere there is so tenuous its responsiveness to a mitigation technology would be easy to detect."
Comment: For more in-depth reading on Tunguska read: Tunguska, Psychopathy and the Sixth Extinction
Location of Sighting: Blackpark Road, Whitchurch, Shropshire
Date of Sighting: Saturday 4th July 2009
Time: 11.20-11.30
Witness Statement: Whilst sitting in the hot tub, looking up at the stars, we both noticed a bright light, which looked similar to a large Chinese lantern, it sort of drifted across the sky in a northerly direction, it suddenly changed direction and headed south east and upwards quite quickly, the light appeared to be a ball of fire, and we watched it for about 4-5 minutes.
Approximately 10 minutes later, we spotted a much bigger fireball in the east, traveling northwards. This object was moving at some considerable speed, and disappeared behind the trees on the horizon. It resembled a large comet, but without a tail. Neither sighting was accompanied by any discernible sound. As we live on the very outskirts of town, we are able to get a good clear view of the night sky with very little distortion from street lighting.
UFOs Northwest
Thu, 30 Jul 2009 16:11 UTC
Posted: July 30, 2009
Date of Sighting: July 26, 2009
Time of Sighting: 2 AM PDT
Location of Sighting: Seattle, Washington (White Center Area)
Description: A large flash momentarily lit up the whole of my neighborhood and I quickly looked up to see what looked like an object burning up in the atmosphere, except at an angle moving AWAY from our atmosphere. There was no "burn trail" and the object was completely silent. It took about a second and was gone without a trace.
Note: The sighting couldn't be a meteor if the object was moving upward. Bright brief flashes in the sky can have other explanations (lightning, electrical power stations, etc). No thunderstorms were known to be in the area at the time of the sighting.
Evidence
indicates that it is highly unlikely that a comet crash would result in
Earth's demise, researchers at the University of Washington said on
Thursday.
Writing in Science Express, the online edition of the journal Science, researchers acknowledged that while most scientists agree that an asteroid collision 65 million years ago caused the mass extinction of the dinosaurs, they tend to differ in opinion on how many other mass extinctions have resulted from similar events.
Researchers used computer models to simulate the formation of comet clouds in the solar system for 1.2 billion years. They pinpointed a body called the Oort Cloud as the source for many long-period comets that find their way into Earth's path.
Formed 4.5 billion years ago from the nebula that formed our solar system, the Oort Cloud spans from about 93 billion miles from the sun to about three light years away. Scientist said the Oort Cloud could contain literally billions of comets, many of which are so small and distant to be seen.
"It was thought the long-period comets we see just tell us about the outer Oort Cloud, but they really give us a murky picture of the entire Oort Cloud," said Nathan Kaib, a University of Washington doctoral student in astronomy and lead author.
Kaib worked alongside Thomas Quinn, astronomy professor at the University of Washington. They found that only two or three significant comet collisions are likely to have occurred on Earth for 500 million years.
They based their calculations on the assumption that the inner Oort Cloud was the primary source of long-period comets, although they admit that the actual number of comets is indefinable.
"For the past 25 years, the inner Oort Cloud has been considered a mysterious, unobserved region of the solar system capable of providing bursts of bodies that occasionally wipe out life on Earth," Quinn said.
"We have shown that comets already discovered can actually be used to estimate an upper limit on the number of bodies in this reservoir."
Their findings could explain a minor event known as the late Eocene extinction 40 million years ago, although Kaib and Quinn noted: "if that relatively minor extinction event was caused by a comet shower, then that was probably the most-intense comet shower since the fossil record began."
"That tells you that the most powerful comet showers caused minor extinctions and other showers should have been less severe, so comet showers are probably not likely causes of mass extinction events," Kaib said.
He added that the Earth has benefited from the gravitational pulls of Jupiter and Saturn, which act as comet deflectors.
"We show that Jupiter and Saturn are not perfect and some of the comets from the inner Oort Cloud are able to leak through. But most don't," Kaib said.
The study was funded by NASA and the National Science Foundation.
Comment: Regarding the claim that "the gravitational pulls of Jupiter and Saturn act as comet deflectors", let's see what Clube and Napier, British astronomers and writers of The Cosmic Serpent, have to say:
Date of Sighting: July 26, 2009
Time of Sighting: 2 AM PDT
Location of Sighting: Seattle, Washington (White Center Area)
Description: A large flash momentarily lit up the whole of my neighborhood and I quickly looked up to see what looked like an object burning up in the atmosphere, except at an angle moving AWAY from our atmosphere. There was no "burn trail" and the object was completely silent. It took about a second and was gone without a trace.
Note: The sighting couldn't be a meteor if the object was moving upward. Bright brief flashes in the sky can have other explanations (lightning, electrical power stations, etc). No thunderstorms were known to be in the area at the time of the sighting.
Red Orbit
Fri, 31 Jul 2009 01:42 UTC
© Unknown
Comet Hale-Bopp.
Comet Hale-Bopp.
Writing in Science Express, the online edition of the journal Science, researchers acknowledged that while most scientists agree that an asteroid collision 65 million years ago caused the mass extinction of the dinosaurs, they tend to differ in opinion on how many other mass extinctions have resulted from similar events.
Researchers used computer models to simulate the formation of comet clouds in the solar system for 1.2 billion years. They pinpointed a body called the Oort Cloud as the source for many long-period comets that find their way into Earth's path.
Formed 4.5 billion years ago from the nebula that formed our solar system, the Oort Cloud spans from about 93 billion miles from the sun to about three light years away. Scientist said the Oort Cloud could contain literally billions of comets, many of which are so small and distant to be seen.
"It was thought the long-period comets we see just tell us about the outer Oort Cloud, but they really give us a murky picture of the entire Oort Cloud," said Nathan Kaib, a University of Washington doctoral student in astronomy and lead author.
Kaib worked alongside Thomas Quinn, astronomy professor at the University of Washington. They found that only two or three significant comet collisions are likely to have occurred on Earth for 500 million years.
They based their calculations on the assumption that the inner Oort Cloud was the primary source of long-period comets, although they admit that the actual number of comets is indefinable.
"For the past 25 years, the inner Oort Cloud has been considered a mysterious, unobserved region of the solar system capable of providing bursts of bodies that occasionally wipe out life on Earth," Quinn said.
"We have shown that comets already discovered can actually be used to estimate an upper limit on the number of bodies in this reservoir."
Their findings could explain a minor event known as the late Eocene extinction 40 million years ago, although Kaib and Quinn noted: "if that relatively minor extinction event was caused by a comet shower, then that was probably the most-intense comet shower since the fossil record began."
"That tells you that the most powerful comet showers caused minor extinctions and other showers should have been less severe, so comet showers are probably not likely causes of mass extinction events," Kaib said.
He added that the Earth has benefited from the gravitational pulls of Jupiter and Saturn, which act as comet deflectors.
"We show that Jupiter and Saturn are not perfect and some of the comets from the inner Oort Cloud are able to leak through. But most don't," Kaib said.
The study was funded by NASA and the National Science Foundation.
Comment: Regarding the claim that "the gravitational pulls of Jupiter and Saturn act as comet deflectors", let's see what Clube and Napier, British astronomers and writers of The Cosmic Serpent, have to say:
The giant comets normally reside far beyond the planets, in a spherical cloud surrounding the Sun, called the Oort cloud. There is also evidence for a flattened disk of comets closer to the inner solar system, called the Edgeworth/Kuiper belt. What prompts members of either of these comet repositories to enter the realm of the planets? Clube and Napier suggest a galactic influence. The solar system periodically passes through the plane of the galaxy as the Sun (and the solar system with it) orbits the galactic center. Each passage may dislodge giant comets and divert them closer to the Sun. The outer planets, particularly Jupiter, may then perturb some of these giant comets into orbits which enter the inner solar system. These comets, stressed both by gravity and by heat from the sun, may fragment into a cloud of smaller objects with dynamically similar orbits.
Chiron offers a good example of a giant comet as called for by Clube and Napier's giant comet hypothesis. Chiron is somewhere between 148 and 208 kilometers in diameter. Currently Chiron's unstable "parking orbit" lies mostly between Saturn and Uranus. Chiron may end up injected into the inner solar system within a hundred thousand years, or ejected from the solar system on a similar time scale. It is also possible that Chiron has already visited the inner solar system.
The Taurid complex and the Kreutz sungrazer group are two families of objects which most likely represent the fragmented remains of two giant comets in the current era. SOHO has recently discovered many new members of the Kreutz group which were previously unknown.
The Kreutz progenitor was injected into a retrograde orbit and attained the sungrazing state at a high inclination to the ecliptic. Hence the debris of its "children" does not pose a threat to the Earth. The Taurid progenitor on the other hand ended up in a short-period low-inclination prograde orbit. This is why the Earth can encounter its debris with potentially calamitous results.
What would happen should the Earth pass through the orbit of a disintegrating giant comet just before or after the comet passes that same point? Since larger fragments tend to cluster close to the nucleus of the comet, chances would increase that the Earth would be bombarded by these larger fragments. The severity of this comet fragment shower would far exceed any ordinary meteor shower. Not only would "shooting stars" and bright fireballs caused by small debris appear, but so too would large airbursts and possibly ground impacts. These would result in significant destruction should they occur over an inhabited area. If a large enough fragment struck in the ocean -- say, 200 meters or so in diameter -- it would raise tsunamis even at a great distance that would sweep away coastal habitations.
Duncan Steel, a colleague of Clube and Napier, refers to this process as coherent catastrophism. Widespread destruction derives from the coherent arrival of many impactors within a few days, as opposed to the sporadic arrival of objects spread randomly in space. The shower repeats for a period of years until the cometary orbit precesses so that the Earth no longer encounters the dense part of the debris field. (Of course, sporadic debris unrelated to the disintegrating comet may impact at any time as well.)
Irene Klotz
Discovery News
Fri, 31 Jul 2009 16:07 UTC
© NASA
Night-Shining Clouds
Night-Shining Clouds
The crash, which leveled trees for hundreds of miles in Siberia, was followed by the appearance of extremely bright clouds, visible by night.
Similar clouds triggered by the flights of space shuttles through atmosphere were found over the planet's poles two days after a launch from Florida, research published in last week's Geophysical Research Letters shows.
The creation of so-called noctilucent, or night-shining clouds from water vapor in shuttle rocket plumes buttresses the theory that the clouds spotted after the 1908 impact were triggered by similar atmospheric dynamics, with the water vapor coming from a comet, lead researcher Michael Kelley told Discovery News.
"The shuttles put 300 metric tons of water vapor at the same region that a comet would," said Kelley, a professor at Cornell University.
The cause of what has been referred to as the "Great Siberian Impact Event," or the "Tunguska Event," has been debated for decades. No meteorite remains have ever been found and the appearance of the mysterious night-shining clouds led many scientists to suspect a comet was responsible.
"It's kind of important that the world got hit by a comet, since Jupiter just got hit again," Kelley said.
Astronomers have been watching an Earth-sized gouge in Jupiter's atmosphere believed to be caused by a comet impact on July 19.
Noctilucent clouds, which form at the edge of space 62 to 68 miles above the planet, are about 10 million times brighter than ordinary clouds. They contain electrically charged ice.
"It's a very difficult region to access," said Clemson University's Miguel Larsen.
The shuttle plumes, which are laced with iron atoms and iron ions, provided researches with a way to track how water vapor is transported by winds and other dynamics of the upper atmosphere.
Noctilucent clouds, which have been increasing in appearance, also can serve to gauge if efforts to mitigate global climate changes are successful, Kelley added.
"It's thought that these clouds are like a miner's canary of global change," he said. "The atmosphere there is so tenuous its responsiveness to a mitigation technology would be easy to detect."
Comment: For more in-depth reading on Tunguska read: Tunguska, Psychopathy and the Sixth Extinction
Tom Callis
Peninsula Daily News
Fri, 31 Jul 2009 16:45 UTC
The cause of loud booming sounds that have shaken houses in and around
Port Angeles, Washington over the past week remains a mystery.
Possible explanations range from naval exercises in the Strait of Juan de Fuca to thunderstorms in the Olympic Mountains.
The Canadian Navy confirmed that the HMCS Edmonton was conducting gunnery exercises with a .50-caliber machine gun in the Strait on Thursday -- but not any other day of the week -- from 10 a.m. to 4 p.m.
But that wouldn't explain why people, such as Marie Barclay of Port Angeles, had her house shaken by loud booms Tuesday and Wednesday.
"It was pretty loud, like a sonic boom," she said.
"All you heard was the boom, and I didn't hear an airplane or nothing like that."
Canadian Navy spokeswoman Lt. Commander Natalie Garcia said that the gun used in Thursday's exercises would sound like a rifle and not an explosion.
The sound wouldn't shake a house on the North Olympic Peninsula, she said.
Garcia said no other Canadian naval exercises have occurred in the Strait this week.
She said U.S. Coast Guard Sector Seattle had the joint-naval exercise area about 3 nautical miles south of Vancouver Island and north of Twin and Pysht reserved from July 24 through Wednesday for gunnery exercises.
But a spokeswoman for Coast Guard Sector Seattle said no such exercises took place this week.
"That's really bizarre, actually," said spokeswoman Tara Molle.
"As far as the on the Coast Guard side, for us, we don't have any training going on up there."
Mike Allen, operations unit controller at Coast Guard Group/Air Station Port Angeles, said the station has not conducted any exercises that would explain the sound.
Allen said he also has heard the loud booms this week.
The Canadian Coast Guard also said it's not the cause.
National Weather Service meteorologist Brent Bower said there were thunderstorms in the Olympic Mountains on Wednesday.
Seven to 10 days
But Georgia Wawro, who lives near Port Angeles High School, said she has heard the loud booms for the past seven to 10 days, including on Thursday.
"It doesn't sound like thunder" or fireworks, she said.
Wawro said she has heard the booms once or twice a day, possibly originating from across the Strait.
"It's not shaky enough to be a sonic boom, but it still rattles my windows," she said.
Clallam County Planning Manager Steve Gray said there has been no quarry blasting or any other permitted explosions this week.
Navy spokesman Sean Hughes said the Navy has not conducted any exercises in the area this week.
A spokesman for McChord Air Force base in Tacoma said he couldn't provide information on flight records in the area without knowing the exact time when loud noises were heard.
But he said the Air Force is not allowed to break the sound barrier, which would create a sonic boom, over populated areas.
The Navy's Blue Angels are in Seattle this week for Seafair, but spokesman Petty Officer Peter Carnicelli said they fly only over Lake Washington and, like the Air Force, the planes not allowed to break the sound barrier.
Possible explanations range from naval exercises in the Strait of Juan de Fuca to thunderstorms in the Olympic Mountains.
The Canadian Navy confirmed that the HMCS Edmonton was conducting gunnery exercises with a .50-caliber machine gun in the Strait on Thursday -- but not any other day of the week -- from 10 a.m. to 4 p.m.
But that wouldn't explain why people, such as Marie Barclay of Port Angeles, had her house shaken by loud booms Tuesday and Wednesday.
"It was pretty loud, like a sonic boom," she said.
"All you heard was the boom, and I didn't hear an airplane or nothing like that."
Canadian Navy spokeswoman Lt. Commander Natalie Garcia said that the gun used in Thursday's exercises would sound like a rifle and not an explosion.
The sound wouldn't shake a house on the North Olympic Peninsula, she said.
Garcia said no other Canadian naval exercises have occurred in the Strait this week.
She said U.S. Coast Guard Sector Seattle had the joint-naval exercise area about 3 nautical miles south of Vancouver Island and north of Twin and Pysht reserved from July 24 through Wednesday for gunnery exercises.
But a spokeswoman for Coast Guard Sector Seattle said no such exercises took place this week.
"That's really bizarre, actually," said spokeswoman Tara Molle.
"As far as the on the Coast Guard side, for us, we don't have any training going on up there."
Mike Allen, operations unit controller at Coast Guard Group/Air Station Port Angeles, said the station has not conducted any exercises that would explain the sound.
Allen said he also has heard the loud booms this week.
The Canadian Coast Guard also said it's not the cause.
National Weather Service meteorologist Brent Bower said there were thunderstorms in the Olympic Mountains on Wednesday.
Seven to 10 days
But Georgia Wawro, who lives near Port Angeles High School, said she has heard the loud booms for the past seven to 10 days, including on Thursday.
"It doesn't sound like thunder" or fireworks, she said.
Wawro said she has heard the booms once or twice a day, possibly originating from across the Strait.
"It's not shaky enough to be a sonic boom, but it still rattles my windows," she said.
Clallam County Planning Manager Steve Gray said there has been no quarry blasting or any other permitted explosions this week.
Navy spokesman Sean Hughes said the Navy has not conducted any exercises in the area this week.
A spokesman for McChord Air Force base in Tacoma said he couldn't provide information on flight records in the area without knowing the exact time when loud noises were heard.
But he said the Air Force is not allowed to break the sound barrier, which would create a sonic boom, over populated areas.
The Navy's Blue Angels are in Seattle this week for Seafair, but spokesman Petty Officer Peter Carnicelli said they fly only over Lake Washington and, like the Air Force, the planes not allowed to break the sound barrier.
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