Rachel Courtland
New Scientist
Tue, 02 Dec 2008 16:23 UTC
Comets that take longer than 200 years to orbit the Sun come from all directions in the sky. That has long led scientists to believe that they were nudged out of a diffuse halo of icy objects that surrounds the solar system - the Oort Cloud.
© www.jonlomberg.com
Oort Cloud objects orbit the Sun in a spherical outer shell shown here, as well as in an inner cloud that might be more disc-like. If the inner cloud is squashed enough, it could be detected in radiation left over from the big bang.
Oort Cloud objects orbit the Sun in a spherical outer shell shown here, as well as in an inner cloud that might be more disc-like. If the inner cloud is squashed enough, it could be detected in radiation left over from the big bang.
The objects probably formed from the same disc of material that gave rise to the planets but were scattered outwards by Jupiter and Saturn a few hundred million years after their birth.
The Oort Cloud is too dim to be seen by telescopes, but astronomers believe it has two components. Based on observations of long-period comets, an outer portion seems to extend from 20,000 to 200,000 astronomical units from the Sun (where 1 AU is the Earth-Sun distance).
Solar system models also predict the existence of an inner shell that stretches some 3000 to 20,000 AU from the Sun. But there is less evidence for this shell - most passing stars are too distant to jostle the inner halo and dislodge comets. Only a few recently spotted objects, such as the icy bodies 2006 SQ372 and Sedna, point to its existence.
Now, a new study suggests that the inner Oort Cloud might be detectable by looking at all-sky surveys of the cosmic microwave background - the first radiation emitted in the universe after the big bang.
© NASA/WMAP Science Team
The cosmic microwave background, the universe's oldest light, could harbour evidence of an asymmetric Oort Cloud.
The cosmic microwave background, the universe's oldest light, could harbour evidence of an asymmetric Oort Cloud.
The inner Oort Cloud objects are dense enough at their orbital distance to block a significant portion of the cosmic radiation. And since the icy debris is roughly -268 °Celsius, about twice as warm as the CMB, it should show up in maps of the radiation.
Passing star
The inner cloud would not be detectable if it formed a perfect sphere, since that would leave the same imprint on the CMB in all directions. However, if a star passed close enough to the Sun to rearrange objects in the inner cloud, the distortions might be visible in the CMB, say Daniel Babich and Avi Loeb of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.
"A star that passes there would actually kick the cloud," say Loeb. "In principle, that would leave a signature that is detectable on the CMB."
The researchers estimate that about five such stars could have passed within 2000 AU of the Sun during the solar system's nearly 5-billion-year lifetime. After each event, it might take a billion years or more for the gravitational pull of distant stars and the Milky Way to smooth out evidence of the star's passage.
Maps made with the European Space Agency's Planck telescope, set to launch in April 2009, might reveal the signal, which could be used to determine the inner Oort Cloud's distance, shape and the distribution of its icy bodies.
Competing signals
"It's an interesting way to look for some sign of the Oort Cloud, which is very hard to do from the Earth," says Renu Malhotra of the University of Arizona in Tucson.
Since it's unclear how aspherical the inner halo is even when it is not deformed by passing stars, the signal might actually be stronger than the authors estimate, Malhotra adds. While the most distant icy bodies would have been very vulnerable to gravitational tugs from passing stars, pushing them into a spherical shell that became the outer Oort Cloud, those closer to the Sun might have retained some of their original disc-like distribution.
In principle, Planck could detect the signal, says cosmologist Douglas Scott of the University of British Columbia in Vancouver, Canada.
But Scott says it's unclear how a signal from the Oort Cloud would compete with the intrinsic signals from the telescope, as well as radiation from the Milky Way and other solar system features, such as the Kuiper Belt, a ring of icy bodies beyond Neptune.
"What is really needed is a more careful simulation which includes at least the effect of the other likely signals," Scott told New Scientist.
Tricky technique
Since the cloud is a relic of the early solar system, pinning down its structure could provide important clues about the formation of the giant planets, Loeb told New Scientist. For example, the size distribution of objects in the cloud could shed light on the structure of the dusty disc from which the planets formed.
Astronomers might also look for stars that dim when Oort Cloud objects pass between them and ground-based telescopes. The technique is tricky because the events are fleeting and detecting them requires a perfect alignment of the objects and telescopes.
Researchers are already on the lookout for such "occultations" of stars by Kuiper Belt Objects that are too small and dim to detect by other methods. Extending the search to inner Oort Cloud objects may be 10 to 20 years off, says Luke Dones of the Southwest Research Institute in Boulder, Colorado.
Still, finding the signature of the Oort Cloud in the CMB could prove even more challenging. "It's not something I think can be done in the near future," Dones told New Scientist. "I suspect these occultation events are going to find Oort Cloud objects sooner."
Journal reference: New Astronomy (vol 14, p 166)
Associated Press
Tue, 02 Dec 2008 21:15 UTC
Honolulu - A University of Hawaii professor says the Big Island will be home to a new telescope.
Professor Robert Fox of the university's Hilo campus says the device can fit into a garage-size building and will search for comet-like objects beyond Neptune.
Fox says it will not be placed atop Mauna Kea, site of several telescopes. He says other Big Island sites are being considered.
The telescope will be part of the four-telescope Taiwan-American Occultation Survey, which seeks to detect and measure relatively small objects of between two and 17 miles in diameter.
Partners in the project include Taiwan's Academia Sinica, the Harvard-Smithsonian Center for Astrophysics, the Lawrence Livermore National Laboratory and Yonsei University in South Korea.
Odd Comet Possibly from Another Star System
Professor Robert Fox of the university's Hilo campus says the device can fit into a garage-size building and will search for comet-like objects beyond Neptune.
Fox says it will not be placed atop Mauna Kea, site of several telescopes. He says other Big Island sites are being considered.
The telescope will be part of the four-telescope Taiwan-American Occultation Survey, which seeks to detect and measure relatively small objects of between two and 17 miles in diameter.
Partners in the project include Taiwan's Academia Sinica, the Harvard-Smithsonian Center for Astrophysics, the Lawrence Livermore National Laboratory and Yonsei University in South Korea.
Odd Comet Possibly from Another Star System
Jeanna Bryner
SPACE.com
Tue, 02 Dec 2008 22:11 UTC
The bizarre chemical make-up of a comet suggests the blob of ice is an
interloper, possibly flung into our solar system from beyond,
astronomers now say, adding that the wacky comet is forcing them to
create a new category for such objects.
The comet, called Machholz 1, was discovered in 1986 by Donald Machholz of Loma Prieta, Calif. Since then, the icy denizen has made a few appearances, including one in 2007.
"A large fraction of comets in our own solar system have escaped into interstellar space, so we expect that many comets formed around other stars would also have escaped," said David Schleicher, a planetary astronomer at Lowell Observatory in Arizona. "Some of these will have crossed paths with the sun, and Machholz 1 could be an interstellar interloper."
The oddball, described in the November issue of the Astronomical Journal, could shed light on the formation and evolution of comets. These blobs of dust and frozen gases may be the oldest, most primitive bodies in the solar system. In fact, they hold the earliest record of material from the nebula that formed the sun and planets.
Head measurements
Schleicher measured the amounts of certain carbon and other compounds in the coma or head of Machholz 1 in 2007. He compared the composition with information from 150 other comets, finding that Machholz 1 had an odd make-up. Particularly, the comet contains much less of a carbon-nitrogen molecule called cyanogen, by a factor of about 72, compared with the average found in other comets. The comet also contained much less of two molecules called C2 and C3 (which have two and three atoms of carbon in their structures, respectively) than the average comet.
Schleicher puts forth three scenarios that could be responsible for the odd chemistry, although no one explanation stands out as right on. "I'm not real thrilled with any of the three [scenarios]," Schleicher told SPACE.com.
One possible explanation is that Machholz 1 did not originate in the solar system, but instead escaped from another star's gravity. In this scenario, the other star's proto-planetary disk (the disk of debris from which planets are thought to form) might have had a lower abundance of carbon, resulting in all carbon-bearing compounds having lower abundances.
Several comets previously in our solar system have gotten the boot when their orbits came into contact with that of Jupiter, whose gravity kicked them out.
Another possible explanation for Machholz 1's anomalous composition is that it formed inside the solar system but even farther from the sun in a colder or more extreme environment than other comets.
A third possibility is that Machholz 1 originated as a so-called carbon-chain depleted comet, but that this chemistry was subsequently altered by extreme heat and so cyanogen was also depleted. While no other comet has exhibited changes in chemistry due to subsequent heating by the sun, Machholz 1's orbit takes the comet to well inside Mercury's orbit every five years. (Other comets get even closer to the sun, but not as often).
"Since its orbit is unusual, we must be suspicious that repeated high temperature cooking might be the cause for its unusual composition," Schleicher said.
However, he added, the only other comet, called Yanaka, to show less cyanogen than is typical never reached such high temperatures.
"This implies that [cyanogen] depletion does not require the chemical reactions associated with extreme heat," Schleicher said.
Class of its own
The results place Machholz 1 into a new class of comets. Until now, astronomers have clumped comets into one of two classes based on their chemical compositions.
Most comets, considered members of the "typical" class, have long resided in the Oort Cloud at the fringes of our solar system but are thought to have originally formed amidst the giant planets, particularly between Saturn, Uranus and Neptune. Other members of this class arrived from the Kuiper Belt, a region of icy objects beyond Neptune (but closer in than the Oort Cloud.)
The second class includes comets with varying depletions of certain carbon molecules, including the C2 and C3 molecules. Nearly all of these comets (called carbon-chain depleted comets) have orbits that suggest they arrived from the Kuiper Belt. For this and other reasons, scientists think the carbon depletion is associated with conditions that existed when the comets formed, perhaps within an outer, colder region of the Kuiper Belt.
The new class of comets, which would include Machholz 1 and possibly Yanaka, would be characterized by low levels of at least three carbon compounds - C2, C3 and cyanogen. And as of now, these comets would be considered of unknown origin, Schleicher said.
The comet, now bound in an orbit around the sun, is expected to come into view again in 2012, at which time Schleicher expects astronomers will point other instruments toward it to measure even more carbon-bearing molecules.
This research was supported by NASA's Planetary Astronomy and Planetary Atmospheres Programs.
Video: Comets Through Time...Myth and Mystery
The Enduring Mysteries of Comets
Image Gallery: Comets
The
international community must work together to tackle the threat of
asteroids colliding with Earth, a leading UN scientist says.
Professor Richard Crowther's comments come as a group of space experts called for a co-ordinated science-led response to the asteroid threat.
The Association of Space Explorers (ASE) says missions to intercept asteroids will need global approval.
The UN will meet in February to discuss the issue.
In the ASE report, the group of scientists and former astronauts point to the historical record to highlight the dangers of asteroids; an impact 65 million years ago may have wiped out the dinosaurs, and the Tunguska impact in 1908 produced a 2,000 sq km fire in Siberia, big enough to engulf a city the size of New York.
They say the next major threatening event could occur in less than 20 years. Asteroid Apophis is due to pass close to the Earth and analyses suggest a one in 45,000 chance of a collision.
An impact by Apophis would generate the equivalent of a 500 megatonne blast, at least 100 times more powerful than the Siberian event.
Professor Crowther of Britain's Science and Technology Facilities Council (STFC), is the chair of the UN Working Group on Near Earth Objects. He says the threat needs to be taken seriously.
"The issue is it's a single event, potentially causing a large number of casualties," be told BBC News.
The UN broadly agrees that action is necessary, though what form this should take is still under discussion.
Collision course
Professor Crowther welcomed the ASE report and said it would be discussed by the UN action team tasked with coming up with a plan, when they meet next February.
"A lot of what's in the report is consistent with what we're suggesting anyway, there needs to be effective scientific co-ordination, enough observatory time, and people looking in the right place at the right time."
The
document says most asteroids entering the Earth's atmosphere are small
and burn up before reaching the surface. But it is the larger ones -
perhaps 200m or more across - that would need to be deflected away from
a collision course with the Earth.
The researchers propose several ways of doing this, the most extreme methods being to crash a spacecraft into the asteroid to knock it off course, or to set off a nuclear explosion. They say the earlier the threat is dealt with, the less drastic the course of action need be.
Professor Crowther says the natural forces of gravity can be used to deflect asteroids in many situations.
"We can use the natural attraction of a probe to one of the bodies, to slowly pull the object away."
He says if done at sufficient distance from the Earth, the orbit of an asteroid can be changed slightly to take it away from a collision path.
ASE propose combining scientific monitoring and research with a global political strategy.
Professor Crowther says the scientific consensus is already broadly in place, but political consensus may take longer.
"We have to decide on a political framework, who's going to act and under what authority. That's clearly a role for the UN within the next two to three years. The key is to get it done before it's needed, when people are much more reasonable, rational and objective."
Comment: Once again, researcher shy away from mentioning the fact that comets are just as much a threat of colliding with Earth as an asteroid is.
Also, the spectacular meteorite siting across Western Canada was never picked up on their Spaceguard telescopes. Or at least we were never warned. So, amid all of their excitement to having spotted one of many meteorites that have entered the earth's atmosphere, their success rate is severely lacking.
Do not depend on the government run space agencies to tell us of a real threat from above. It all depends on the PTB's agenda on what we are told about anything.
The comet, called Machholz 1, was discovered in 1986 by Donald Machholz of Loma Prieta, Calif. Since then, the icy denizen has made a few appearances, including one in 2007.
© SOHO/LASCO (ESA & NASA)
This image taken by the ESA-NASA sunwatching spacecraft SOHO reveals Comet Machholz 1 close to the sun on Jan. 8, 2002. SOHO's coronograph hid the bright sun, the size of which is shown by the inner ring.
This image taken by the ESA-NASA sunwatching spacecraft SOHO reveals Comet Machholz 1 close to the sun on Jan. 8, 2002. SOHO's coronograph hid the bright sun, the size of which is shown by the inner ring.
"A large fraction of comets in our own solar system have escaped into interstellar space, so we expect that many comets formed around other stars would also have escaped," said David Schleicher, a planetary astronomer at Lowell Observatory in Arizona. "Some of these will have crossed paths with the sun, and Machholz 1 could be an interstellar interloper."
The oddball, described in the November issue of the Astronomical Journal, could shed light on the formation and evolution of comets. These blobs of dust and frozen gases may be the oldest, most primitive bodies in the solar system. In fact, they hold the earliest record of material from the nebula that formed the sun and planets.
Head measurements
Schleicher measured the amounts of certain carbon and other compounds in the coma or head of Machholz 1 in 2007. He compared the composition with information from 150 other comets, finding that Machholz 1 had an odd make-up. Particularly, the comet contains much less of a carbon-nitrogen molecule called cyanogen, by a factor of about 72, compared with the average found in other comets. The comet also contained much less of two molecules called C2 and C3 (which have two and three atoms of carbon in their structures, respectively) than the average comet.
Schleicher puts forth three scenarios that could be responsible for the odd chemistry, although no one explanation stands out as right on. "I'm not real thrilled with any of the three [scenarios]," Schleicher told SPACE.com.
One possible explanation is that Machholz 1 did not originate in the solar system, but instead escaped from another star's gravity. In this scenario, the other star's proto-planetary disk (the disk of debris from which planets are thought to form) might have had a lower abundance of carbon, resulting in all carbon-bearing compounds having lower abundances.
Several comets previously in our solar system have gotten the boot when their orbits came into contact with that of Jupiter, whose gravity kicked them out.
Another possible explanation for Machholz 1's anomalous composition is that it formed inside the solar system but even farther from the sun in a colder or more extreme environment than other comets.
A third possibility is that Machholz 1 originated as a so-called carbon-chain depleted comet, but that this chemistry was subsequently altered by extreme heat and so cyanogen was also depleted. While no other comet has exhibited changes in chemistry due to subsequent heating by the sun, Machholz 1's orbit takes the comet to well inside Mercury's orbit every five years. (Other comets get even closer to the sun, but not as often).
"Since its orbit is unusual, we must be suspicious that repeated high temperature cooking might be the cause for its unusual composition," Schleicher said.
However, he added, the only other comet, called Yanaka, to show less cyanogen than is typical never reached such high temperatures.
"This implies that [cyanogen] depletion does not require the chemical reactions associated with extreme heat," Schleicher said.
Class of its own
The results place Machholz 1 into a new class of comets. Until now, astronomers have clumped comets into one of two classes based on their chemical compositions.
Most comets, considered members of the "typical" class, have long resided in the Oort Cloud at the fringes of our solar system but are thought to have originally formed amidst the giant planets, particularly between Saturn, Uranus and Neptune. Other members of this class arrived from the Kuiper Belt, a region of icy objects beyond Neptune (but closer in than the Oort Cloud.)
The second class includes comets with varying depletions of certain carbon molecules, including the C2 and C3 molecules. Nearly all of these comets (called carbon-chain depleted comets) have orbits that suggest they arrived from the Kuiper Belt. For this and other reasons, scientists think the carbon depletion is associated with conditions that existed when the comets formed, perhaps within an outer, colder region of the Kuiper Belt.
The new class of comets, which would include Machholz 1 and possibly Yanaka, would be characterized by low levels of at least three carbon compounds - C2, C3 and cyanogen. And as of now, these comets would be considered of unknown origin, Schleicher said.
The comet, now bound in an orbit around the sun, is expected to come into view again in 2012, at which time Schleicher expects astronomers will point other instruments toward it to measure even more carbon-bearing molecules.
This research was supported by NASA's Planetary Astronomy and Planetary Atmospheres Programs.
Video: Comets Through Time...Myth and Mystery
The Enduring Mysteries of Comets
Image Gallery: Comets
Julian Siddle
BBC News
Tue, 02 Dec 2008 21:22 UTC
© NASA
Scientists say asteroids can be deflected to stop them hitting the Earth
Scientists say asteroids can be deflected to stop them hitting the Earth
Professor Richard Crowther's comments come as a group of space experts called for a co-ordinated science-led response to the asteroid threat.
The Association of Space Explorers (ASE) says missions to intercept asteroids will need global approval.
The UN will meet in February to discuss the issue.
In the ASE report, the group of scientists and former astronauts point to the historical record to highlight the dangers of asteroids; an impact 65 million years ago may have wiped out the dinosaurs, and the Tunguska impact in 1908 produced a 2,000 sq km fire in Siberia, big enough to engulf a city the size of New York.
They say the next major threatening event could occur in less than 20 years. Asteroid Apophis is due to pass close to the Earth and analyses suggest a one in 45,000 chance of a collision.
An impact by Apophis would generate the equivalent of a 500 megatonne blast, at least 100 times more powerful than the Siberian event.
Professor Crowther of Britain's Science and Technology Facilities Council (STFC), is the chair of the UN Working Group on Near Earth Objects. He says the threat needs to be taken seriously.
"The issue is it's a single event, potentially causing a large number of casualties," be told BBC News.
The UN broadly agrees that action is necessary, though what form this should take is still under discussion.
Collision course
Professor Crowther welcomed the ASE report and said it would be discussed by the UN action team tasked with coming up with a plan, when they meet next February.
"A lot of what's in the report is consistent with what we're suggesting anyway, there needs to be effective scientific co-ordination, enough observatory time, and people looking in the right place at the right time."
© NASA
Past space impacts have left huge craters
Past space impacts have left huge craters
The researchers propose several ways of doing this, the most extreme methods being to crash a spacecraft into the asteroid to knock it off course, or to set off a nuclear explosion. They say the earlier the threat is dealt with, the less drastic the course of action need be.
Professor Crowther says the natural forces of gravity can be used to deflect asteroids in many situations.
"We can use the natural attraction of a probe to one of the bodies, to slowly pull the object away."
He says if done at sufficient distance from the Earth, the orbit of an asteroid can be changed slightly to take it away from a collision path.
ASE propose combining scientific monitoring and research with a global political strategy.
Professor Crowther says the scientific consensus is already broadly in place, but political consensus may take longer.
"We have to decide on a political framework, who's going to act and under what authority. That's clearly a role for the UN within the next two to three years. The key is to get it done before it's needed, when people are much more reasonable, rational and objective."
Comment: Once again, researcher shy away from mentioning the fact that comets are just as much a threat of colliding with Earth as an asteroid is.
Also, the spectacular meteorite siting across Western Canada was never picked up on their Spaceguard telescopes. Or at least we were never warned. So, amid all of their excitement to having spotted one of many meteorites that have entered the earth's atmosphere, their success rate is severely lacking.
Do not depend on the government run space agencies to tell us of a real threat from above. It all depends on the PTB's agenda on what we are told about anything.
United Press International
Thu, 04 Dec 2008 19:41 UTC
A U.S.-led group, the Association of Space Explorers, says the
international community must develop a coordinated response to the
threat of asteroids.
The group, which represents 320 individuals from 34 nations who have flown in space, said the asteroid Apophis is to pass close to the Earth in 2036, with a one in 45,000 chance of a collision. An impact by Apophis would generate the equivalent of a 500-megaton blast and inflict enormous damage, the group said in a report released in September.
Richard Crowther of Britain's Science and Technology Facilities Council and chair of the U.N. Working Group on Near Earth Objects said the report will be discussed by a U.N. action team in February.
"A lot of what's in the report is consistent with what we're suggesting anyway, there needs to be effective scientific co-ordination, enough observatory time and people looking in the right place at the right time," he told the BBC.
Astronomers
from Caltech and NASA say a strong shower of Leonid meteors is coming
in 2009. Their prediction follows an outburst on Nov. 17, 2008, that
broke several years of "Leonid quiet" and heralds even more intense
activity next November.
"On Nov. 17, 2009, we expect the Leonids to produce upwards of 500 meteors per hour," says Bill Cooke of the NASA Marshall Space Flight Center. "That's a very strong display."
Forecasters define a meteor storm as 1000 or more meteors per hour. That would make the 2009 Leonids "a half-storm," says Jeremie Vaubaillon of Caltech, who successfully predicted a related outburst just a few weeks ago.
On Nov. 17, 2008, Earth passed through a stream of debris from comet 55P/Tempel-Tuttle. The gritty, dusty debris stream was laid down by the Leonids' parent comet more than five hundred years ago in 1466. Almost no one expected the old stream to produce a very strong shower, but it did. Observers in Asia and Europe counted as many as 100 meteors per hour.
Vaubaillon
predicted the crossing with one-hour precision. "I have a computer
program that calculates the orbits of Leonid debris streams," he
explains. "It does a good job anticipating encounters even with very
old streams like this one."
The Nov. 17, 2008 outburst proved that the 1466 stream is rich in meteor-producing debris, setting the stage for an even better display in 2009.
On Nov. 17, 2009, Earth will pass through the 1466 stream again, but this time closer to the center. Based on the number of meteors observed in 2008, Vaubaillon can estimate the strength of the coming display: five hundred or more Leonids per hour during a few-hour peak centered on 21:43 UT.
"Our own independent model of the debris stream agrees," says Cooke. "We predict a sub-storm level outburst on Nov. 17, 2009, peaking sometime between 21:34 and 21:44 UT."
The timing favors observers in Asia, although Cooke won't rule out a nice show over North America when darkness falls hours after the peak. "I hope so," he says. "It's a long way to Mongolia."
Many readers will remember the great Leonid showers of 1998-2002. The best years (1999 and 2001) produced storms of up to 3000 Leonids per hour. The 2009 display won't be so intense. Instead, if predictions are correct, next year's shower could resemble the 1998 Leonids, a "half-storm"-level event caused by a stream dating from 1333. That old stream turned out to be rich in nugget-sized debris that produced an abundance of fireballs. Many observers consider the 1998 Leonids to be the best they've ever seen.
Could 2009 be the same? Vaubaillon expects a similar number of meteors but fewer fireballs. If the models are correct, the 1466 stream in Earth's path contains plenty of dust but not so many nuggets, thus reducing the fireball count. On the bright side, the Moon will be new next Nov. 17th so nothing will stand in the way of the shower reaching its full potential.
Less than a month after a fireball meteor tore through Canadian skies, astronomer Christ Peterson of Cloudbait Observatory photographed a fireball near Colorado Springs, Colorado.
In a posting to an astronomy discussion group, Peterson said:
The group, which represents 320 individuals from 34 nations who have flown in space, said the asteroid Apophis is to pass close to the Earth in 2036, with a one in 45,000 chance of a collision. An impact by Apophis would generate the equivalent of a 500-megaton blast and inflict enormous damage, the group said in a report released in September.
Richard Crowther of Britain's Science and Technology Facilities Council and chair of the U.N. Working Group on Near Earth Objects said the report will be discussed by a U.N. action team in February.
"A lot of what's in the report is consistent with what we're suggesting anyway, there needs to be effective scientific co-ordination, enough observatory time and people looking in the right place at the right time," he told the BBC.
NASA
Thu, 04 Dec 2008 23:24 UTC
© Chris Peterson, Cloudbait Observatory
A composite, all-sky image of the 2008 Leonid outburst over Colorado.
A composite, all-sky image of the 2008 Leonid outburst over Colorado.
"On Nov. 17, 2009, we expect the Leonids to produce upwards of 500 meteors per hour," says Bill Cooke of the NASA Marshall Space Flight Center. "That's a very strong display."
Forecasters define a meteor storm as 1000 or more meteors per hour. That would make the 2009 Leonids "a half-storm," says Jeremie Vaubaillon of Caltech, who successfully predicted a related outburst just a few weeks ago.
On Nov. 17, 2008, Earth passed through a stream of debris from comet 55P/Tempel-Tuttle. The gritty, dusty debris stream was laid down by the Leonids' parent comet more than five hundred years ago in 1466. Almost no one expected the old stream to produce a very strong shower, but it did. Observers in Asia and Europe counted as many as 100 meteors per hour.
© International Meteor Organization
Meteor counts for the 2008 Leonid outburst.
Meteor counts for the 2008 Leonid outburst.
The Nov. 17, 2008 outburst proved that the 1466 stream is rich in meteor-producing debris, setting the stage for an even better display in 2009.
On Nov. 17, 2009, Earth will pass through the 1466 stream again, but this time closer to the center. Based on the number of meteors observed in 2008, Vaubaillon can estimate the strength of the coming display: five hundred or more Leonids per hour during a few-hour peak centered on 21:43 UT.
"Our own independent model of the debris stream agrees," says Cooke. "We predict a sub-storm level outburst on Nov. 17, 2009, peaking sometime between 21:34 and 21:44 UT."
The timing favors observers in Asia, although Cooke won't rule out a nice show over North America when darkness falls hours after the peak. "I hope so," he says. "It's a long way to Mongolia."
Many readers will remember the great Leonid showers of 1998-2002. The best years (1999 and 2001) produced storms of up to 3000 Leonids per hour. The 2009 display won't be so intense. Instead, if predictions are correct, next year's shower could resemble the 1998 Leonids, a "half-storm"-level event caused by a stream dating from 1333. That old stream turned out to be rich in nugget-sized debris that produced an abundance of fireballs. Many observers consider the 1998 Leonids to be the best they've ever seen.
Could 2009 be the same? Vaubaillon expects a similar number of meteors but fewer fireballs. If the models are correct, the 1466 stream in Earth's path contains plenty of dust but not so many nuggets, thus reducing the fireball count. On the bright side, the Moon will be new next Nov. 17th so nothing will stand in the way of the shower reaching its full potential.
KGW.com
Sat, 06 Dec 2008 13:05 UTC
Some Oregonians from Bend to Portland reported a bright fireball flash across the northern sky Thursday night.
Bend station KTVZ reported all of the sightings just after 5 p.m.
Rod Wells told the station he had just pulled out of the Hooker Creek rental yard in La Pine and was heading north on Highway 97.
"I just went, 'Wow, look at that!'" he recalled.
Witnesses described it as green with some orange streaking across the night sky.
Meteorite expert Dick Pugh told KTVZ.COM he got six calls about the sighting, three on each side of the Cascades.
"One northwest of Portland said it was headed for China Hat," Pugh said. "There's no evidence of sonic booms or sound effects." We're past the Leonid meteor shower, he said, adding, "This is a 'stray,' it appears."
No law enforcement reported any calls about the object.
In February, a meteor was caught on camera streaking across a wide area of the Pacific Northwest.
(KTVZ.com Producer Barney Lerten contributed to this report)
Bend station KTVZ reported all of the sightings just after 5 p.m.
Rod Wells told the station he had just pulled out of the Hooker Creek rental yard in La Pine and was heading north on Highway 97.
"I just went, 'Wow, look at that!'" he recalled.
Witnesses described it as green with some orange streaking across the night sky.
Meteorite expert Dick Pugh told KTVZ.COM he got six calls about the sighting, three on each side of the Cascades.
"One northwest of Portland said it was headed for China Hat," Pugh said. "There's no evidence of sonic booms or sound effects." We're past the Leonid meteor shower, he said, adding, "This is a 'stray,' it appears."
No law enforcement reported any calls about the object.
In February, a meteor was caught on camera streaking across a wide area of the Pacific Northwest.
(KTVZ.com Producer Barney Lerten contributed to this report)
Patricia Phillips
Space News Examiner
Sat, 06 Dec 2008 19:20 UTC
© Cloudbait
In a posting to an astronomy discussion group, Peterson said:
Early this morning (2008.12.06 01:06 MST, 08:06 UT) I recorded what IPeterson also posted a video of the fireball. The image, above, is courtesy of Peterson and Cloudbait Observatory.
believe is my brightest fireball ever. I'm currently estimating a magnitude
of -18, some 100 times brighter than a full Moon. There appear to have been
some thin clouds, so it was probably even brighter. I don't yet know if it's
on other cameras. The terminal explosion appears to be fairly close to
Colorado Springs.
Robin McKie
Guardian UK
Sun, 07 Dec 2008 03:21 UTC
Scientists call for £68m a year to detect danger, and more for spacecraft to defend against it.
A group of the world's leading scientists has urged the United Nations to establish an international network to search the skies for asteroids on a collision course with Earth. The spaceguard system would also be responsible for deploying spacecraft that could destroy or deflect incoming objects.
The group - which includes the Royal Society president Lord Rees and environmentalist Crispin Tickell - said that the UN needed to act as a matter of urgency. Although an asteroid collision with the planet is a relatively remote risk, the consequences of a strike would be devastating.
An asteroid that struck the Earth 65 million years ago wiped out the dinosaurs and 70 per cent of the species then living on the planet. The destruction of the Tunguska region of Siberia in 1908 is known to have been caused by the impact of a large extraterrestrial object.
'The international community must begin work now on forging three impact prevention elements - warning, deflection technology and a decision-making process - into an effective defence against a future collision,' said the International Panel on Asteroid Threat Mitigation, which is chaired by former American astronaut Russell Schweickart. The panel made its presentation at the UN's building in Vienna.
The risk of a significantly sized asteroid - defined by the panel as being more than 45 metres in diameter - striking the Earth has been calculated at two or three such events every 1,000 years, a rare occurrence, though such a collision would dwarf all other natural disasters in recent history.
The panel added that developments in telescope design mean that, by 2020, it should be possible to pinpoint about 500,000 asteroids in orbit round the Sun and study their movements. Of these, several dozen will be revealed to pose threats to Earth, the panel added.
However, the group warned it would be impossible to predict exactly which of these 'at-risk' asteroids would actually strike until it was very close to our planet. By then, it would be too late to take action.
As a result, the panel said it would be necessary to launch missions to deflect or destroy asteroids that have only a one in 10, or even a one in 100, risk of hitting our planet. 'Over the next 10 to 15 years, the process of discovering asteroids will likely identify dozens of new objects threatening enough that they will require proactive decisions by the United Nations,' the report added. In addition, such missions will have to be launched well ahead of a predicted impact, so that slight deflections by spaceships can induce major changes in an asteroid's paths years later. The world will not be able to rely on Bruce Willis saving it from an asteroid at the last minute as he does in Armageddon, in other words. Considerable planning and forethought will be needed.
Funding such missions will therefore require far greater investment than is currently being made by international authorities. At present, about $4m (£2.7m) a year is spent by Nasa on asteroid detection, while the European Space Agency's planned mission to study the asteroid Apophis - which astronomers calculate has a 1 in 45,000 chance of striking the Earth this century - is likely to be a modest project costing only a few tens of millions of dollars.
By contrast, any effective protection system will require funding of about $100m (£68m) a year to provide a full survey of the skies, combined with investment in spacecraft that can reach an asteroid and then deflect it. This would be achieved either by crashing the spacecraft on to the asteroid or by triggering a nuclear explosion in space.
However, the cost of such missions should not be used as an excuse for failing to act, added the panel. 'We are no longer passive victims of the impact process,' it concluded. 'We cannot shirk the responsibility.'
A group of the world's leading scientists has urged the United Nations to establish an international network to search the skies for asteroids on a collision course with Earth. The spaceguard system would also be responsible for deploying spacecraft that could destroy or deflect incoming objects.
The group - which includes the Royal Society president Lord Rees and environmentalist Crispin Tickell - said that the UN needed to act as a matter of urgency. Although an asteroid collision with the planet is a relatively remote risk, the consequences of a strike would be devastating.
An asteroid that struck the Earth 65 million years ago wiped out the dinosaurs and 70 per cent of the species then living on the planet. The destruction of the Tunguska region of Siberia in 1908 is known to have been caused by the impact of a large extraterrestrial object.
'The international community must begin work now on forging three impact prevention elements - warning, deflection technology and a decision-making process - into an effective defence against a future collision,' said the International Panel on Asteroid Threat Mitigation, which is chaired by former American astronaut Russell Schweickart. The panel made its presentation at the UN's building in Vienna.
The risk of a significantly sized asteroid - defined by the panel as being more than 45 metres in diameter - striking the Earth has been calculated at two or three such events every 1,000 years, a rare occurrence, though such a collision would dwarf all other natural disasters in recent history.
The panel added that developments in telescope design mean that, by 2020, it should be possible to pinpoint about 500,000 asteroids in orbit round the Sun and study their movements. Of these, several dozen will be revealed to pose threats to Earth, the panel added.
However, the group warned it would be impossible to predict exactly which of these 'at-risk' asteroids would actually strike until it was very close to our planet. By then, it would be too late to take action.
As a result, the panel said it would be necessary to launch missions to deflect or destroy asteroids that have only a one in 10, or even a one in 100, risk of hitting our planet. 'Over the next 10 to 15 years, the process of discovering asteroids will likely identify dozens of new objects threatening enough that they will require proactive decisions by the United Nations,' the report added. In addition, such missions will have to be launched well ahead of a predicted impact, so that slight deflections by spaceships can induce major changes in an asteroid's paths years later. The world will not be able to rely on Bruce Willis saving it from an asteroid at the last minute as he does in Armageddon, in other words. Considerable planning and forethought will be needed.
Funding such missions will therefore require far greater investment than is currently being made by international authorities. At present, about $4m (£2.7m) a year is spent by Nasa on asteroid detection, while the European Space Agency's planned mission to study the asteroid Apophis - which astronomers calculate has a 1 in 45,000 chance of striking the Earth this century - is likely to be a modest project costing only a few tens of millions of dollars.
By contrast, any effective protection system will require funding of about $100m (£68m) a year to provide a full survey of the skies, combined with investment in spacecraft that can reach an asteroid and then deflect it. This would be achieved either by crashing the spacecraft on to the asteroid or by triggering a nuclear explosion in space.
However, the cost of such missions should not be used as an excuse for failing to act, added the panel. 'We are no longer passive victims of the impact process,' it concluded. 'We cannot shirk the responsibility.'
Sun, 07 Dec 2008 07:12 UTC
SpaceWeather.com
Last night, Dec. 6th at 1:06 a.m. MST, a meteor of stunning brightness
lit up the skies of Colorado. Astronomer Chris Peterson photographed the event using a dedicated all-sky meteor camera in the town of Guffey, near Colorado Springs:
"In seven years of operation, this is the brightest fireball I've ever recorded," says Peterson. "I estimate the terminal explosion at magnitude -18, more than 100 times brighter than a full Moon."
Fireballs this bright belong to a rare category of meteors called superbolides. They are caused by small asteroids measuring a few to 10 meters in diameter and massing hundreds of metric tons. Superbolides trigger seismic detectors on the ground, produce waves of infrasound that can travel thousands of miles, and they are tracked by military satellites scanning Earth for nuclear explosions. Recent examples include the El Paso fireball of 1997 and the Slovenian Superbolide of 2007.
Last night's fireball is on the low end of the superbolide scale. Nevertheless, it was still a beauty and likely peppered the ground with meteorites when it exploded. Sighting reports are welcomed; they could help guide the tracking and recovery of debris.
LISTEN! 250 miles south of the fireball, radio astronomer Thomas Ashcraft of New Mexico photographed the flash and recorded radio echoes from the superbolide's ion trail. Click here to listen.
While
space rocks hurtling in from space threaten to deal modern life a
mortal blow, meteorite impacts during Earth's early history may have
played a pivotal role in kick-starting life on the planet.
Exactly how and when organic molecules appeared in abundance on the young Earth, leading to the origin of life about 4 billion years ago, has been unclear. But new research suggests that meteor impacts could have created amino acids, the building blocks of life.
Yoshihiro Furukawa at Tohoku University in Sendai, Japan, and colleagues used a high-velocity propellant gun to simulate the impacts of ordinary carbon-containing chondrite meteorites - the most common type of meteorite - into the early ocean. Afterwards, they recovered a variety of organic molecules, including fatty acids, amines, and an amino acid.
Ocean incubator
Oceans began to form about 4.3 billion years ago, when meteorites were hitting Earth about 1000 times more frequently than they do today, says Furukawa. "This study is the first to show that an amino acid can be synthesised by a naturally possible mechanism on the early Earth," he says.
Although the team generated only one type of amino acid, they suspect that by varying the conditions of their experimental impacts, they will be able to generate others.
In earlier meteorite impact studies, the team generated fine particles, which they say had the potential to become clay. During an impact, clay could have trapped substantial amounts of the organic molecules formed in the same event, and then settled as marine sediment, the researchers say.
Some of these organic molecules might have evolved as a precursor to life; the rest might have sunk to the deep crust and mantle to become graphite or diamond, they say.
Journal reference: Nature Geoscience (DOI: link)
© Chris Peterson
"In seven years of operation, this is the brightest fireball I've ever recorded," says Peterson. "I estimate the terminal explosion at magnitude -18, more than 100 times brighter than a full Moon."
Fireballs this bright belong to a rare category of meteors called superbolides. They are caused by small asteroids measuring a few to 10 meters in diameter and massing hundreds of metric tons. Superbolides trigger seismic detectors on the ground, produce waves of infrasound that can travel thousands of miles, and they are tracked by military satellites scanning Earth for nuclear explosions. Recent examples include the El Paso fireball of 1997 and the Slovenian Superbolide of 2007.
Last night's fireball is on the low end of the superbolide scale. Nevertheless, it was still a beauty and likely peppered the ground with meteorites when it exploded. Sighting reports are welcomed; they could help guide the tracking and recovery of debris.
LISTEN! 250 miles south of the fireball, radio astronomer Thomas Ashcraft of New Mexico photographed the flash and recorded radio echoes from the superbolide's ion trail. Click here to listen.
Emma Young
New Scientist
Mon, 08 Dec 2008 18:23 UTC
© Don Davis/NASA
Meteorite impacts during Earth's early history may have played a pivotal role in kick-starting life.
Meteorite impacts during Earth's early history may have played a pivotal role in kick-starting life.
Exactly how and when organic molecules appeared in abundance on the young Earth, leading to the origin of life about 4 billion years ago, has been unclear. But new research suggests that meteor impacts could have created amino acids, the building blocks of life.
Yoshihiro Furukawa at Tohoku University in Sendai, Japan, and colleagues used a high-velocity propellant gun to simulate the impacts of ordinary carbon-containing chondrite meteorites - the most common type of meteorite - into the early ocean. Afterwards, they recovered a variety of organic molecules, including fatty acids, amines, and an amino acid.
Ocean incubator
Oceans began to form about 4.3 billion years ago, when meteorites were hitting Earth about 1000 times more frequently than they do today, says Furukawa. "This study is the first to show that an amino acid can be synthesised by a naturally possible mechanism on the early Earth," he says.
Although the team generated only one type of amino acid, they suspect that by varying the conditions of their experimental impacts, they will be able to generate others.
In earlier meteorite impact studies, the team generated fine particles, which they say had the potential to become clay. During an impact, clay could have trapped substantial amounts of the organic molecules formed in the same event, and then settled as marine sediment, the researchers say.
Some of these organic molecules might have evolved as a precursor to life; the rest might have sunk to the deep crust and mantle to become graphite or diamond, they say.
Journal reference: Nature Geoscience (DOI: link)
Wed, 03 Dec 2008 02:49 UTC
Entertainment and Showbiz!
Scientists have found new evidence suggesting a giant tsunami that
crashed in New York City 2,300 years ago, was caused by an asteroid 330
feet in diameter, which slammed into the Atlantic Ocean nearby.
According to a report in Discovery News, Katherine Cagen of Harvard University and a team of researchers found clues in the form of slit in the Hudson River, which indicates an asteroid impact in the past.
While sifting through samples, the researchers found carbon spherules, which are perfectly round particles that form in the extreme pressures of an impact.
"But the main thing that closes the deal is that we looked in the spherules and found nano-diamonds," said Dallas Abbott of Columbia University, a co-author on the work. "These have only been found in impact ejecta or in meteorites," he added.
The team found grains of several shocked minerals in the sediments as well.
So far, the team has only found impact ejecta in deposits in the Hudson, with some as far as 50 kilometers (31 miles) upriver from the mouth. But, they have taken samples of suspicious-looking sediments along the coasts of New Jersey and Long Island as well, and hope to find more of the same strange minerals pointing to an impact origin.
"We've had strong storms in New York's history that haven't made deposits anything like this," Cagen said. "We don't know how big it was, but it would have been more than a splash against Manhattan; the city would have been devastated," she added.
Cagen is convinced her team's work proves an impact caused the tsunami, but admits they'll need to find the smoking gun - a crater, probably buried in the continental shelf off New Jersey - to convince skeptics.
"We're making the pretty outrageous claim that not only did a tsunami hit the New York metropolitan area 2,300 years ago, but it was caused by an asteroid impact for which we can't find a crater," she said.
Less than a month after a fireball meteor tore through Canadian skies, astronomer Christ Peterson of Cloudbait Observatory photographed a fireball near Colorado Springs, Colorado.
In a posting to an astronomy discussion group, Peterson said:
It
certainly captures the imagination: a star passing silently by our
solar system knocks a deadly barrage of comets towards Earth. However,
recent simulations by one group of researchers has shown that these
star-induced comet showers may not be as dramatic as once thought.
The idea of nearby stars influencing comets goes back to 1950, when the astronomer Jan Hendrik Oort hypothesized an invisible repository of comets - the so-called Oort cloud - swarming around the solar system out to a distance of 100,000 AU (one AU is the distance between the sun and the Earth).
Oort assumed that stars passing through the cloud would cause a fresh batch of comets to fall in towards the sun, where they become visible to astronomers. Such a disturbance could have long term effects.
"The comets we see now could be from a stellar passage hundreds of millions of years ago," said Hans Rickman of the Uppsala Astronomical Observatory in Sweden.
However, Rickman and his colleagues have confirmed that star encounters alone cannot explain comet behavior. Using a computer model of the Oort cloud, they show that gravity effects from the galaxy are equally important. The results are reported in a recent article in the journal Celestial Mechanics and Dynamical Astronomy.
Two stars passing in the night
Although Earth has almost certainly been hit by comets throughout its history, it is not all that clear how often that has happened. Much of the crater history on Earth has been erased because of erosion or tectonic activity. The remaining craters could have come from asteroids instead of comets.
"It's quite difficult to tell a comet-induced crater from an asteroid one, since the impactor gets essentially vaporized," Rickman said.
Comet impacts are, however, likely to be more energetic (and therefore more damaging), since comets are moving much faster than asteroids when they pass by Earth.
Comet orbits can be altered whenever another star comes within 10,000 AU of our sun. Such a close encounter - occurring every 100 million years or so - will not typically disturb asteroids or planets, but it definitely "shakes up the whole Oort cloud," Rickman said.
Most scientists have presumed that these star crossings will lead to a shower of comets raining down on the Earth and the rest of the inner solar system. Some have even claimed to find evidence of periodic mass extinctions that might be explained by a single (as-yet-unidentified) star in an elliptical orbit around the sun.
To study the effect of stellar perturbations, Rickman and his colleagues model the Oort cloud with a sample of one million comets (the true number of cloud comets is unknown, but certainly much higher). The simulations are allowed to run for a time period corresponding to the 5-billion-year age of the solar system.
The results show that stars can induce comet showers, but the contrast with non-shower periods is less than what people have thought before, Rickman said. This leveling out in comet activity is due to the influence of the gravitational field of the Milky Way.
Galactic tide
Astronomers
have known for some time that our galaxy's gravity has an influence on
the Oort cloud. Specifically, the cloud experiences a tidal effect due
to the fact that the gravitational field is stronger the closer one is
to the plane of the galaxy.
The simulations by Rickman and colleagues show how the galactic tide constantly gives a small nudge to the cloud's comets. Some of these comets are in rather unstable orbits to begin with, so the slight push can send them on a sun-bound trajectory. Eventually, however, all these unstable comets are ejected from the solar system.
And this is where stellar encounters become important. They scramble the Oort cloud, so that the galactic tide has a new crop of unstable comets to funnel into the inner solar system.
"The general picture spawned by our results is that injection of comets from the Oort Cloud is essentially to be seen as a team work involving both tides and stars," the scientists write in their paper.
This star-tide collaboration keeps a relatively steady supply of comets zooming nearby, so the threat from comet impacts probably does not change much over time.
Comment: Have you read Cosmic Turkey Shoot?
According to a report in Discovery News, Katherine Cagen of Harvard University and a team of researchers found clues in the form of slit in the Hudson River, which indicates an asteroid impact in the past.
While sifting through samples, the researchers found carbon spherules, which are perfectly round particles that form in the extreme pressures of an impact.
"But the main thing that closes the deal is that we looked in the spherules and found nano-diamonds," said Dallas Abbott of Columbia University, a co-author on the work. "These have only been found in impact ejecta or in meteorites," he added.
The team found grains of several shocked minerals in the sediments as well.
So far, the team has only found impact ejecta in deposits in the Hudson, with some as far as 50 kilometers (31 miles) upriver from the mouth. But, they have taken samples of suspicious-looking sediments along the coasts of New Jersey and Long Island as well, and hope to find more of the same strange minerals pointing to an impact origin.
"We've had strong storms in New York's history that haven't made deposits anything like this," Cagen said. "We don't know how big it was, but it would have been more than a splash against Manhattan; the city would have been devastated," she added.
Cagen is convinced her team's work proves an impact caused the tsunami, but admits they'll need to find the smoking gun - a crater, probably buried in the continental shelf off New Jersey - to convince skeptics.
"We're making the pretty outrageous claim that not only did a tsunami hit the New York metropolitan area 2,300 years ago, but it was caused by an asteroid impact for which we can't find a crater," she said.
Patricia Phillips
Space News Examiner
Sat, 06 Dec 2008 19:20 UTC
© Cloudbait
In a posting to an astronomy discussion group, Peterson said:
Early this morning (2008.12.06 01:06 MST, 08:06 UT) I recorded what I believe is my brightest fireball ever. I'm currently estimating a magnitude of -18, some 100 times brighter than a full Moon. There appear to have been some thin clouds, so it was probably even brighter. I don't yet know if it's on other cameras. The terminal explosion appears to be fairly close to Colorado Springs.Peterson also posted a video of the fireball. The image, above, is courtesy of Peterson and Cloudbait Observatory.
Michael Schirber
Astrobiology Magazine
Fri, 12 Dec 2008 16:28 UTC
© Lick Observatory
Halley's Comet becomes visible to the unaided eye about every 76 years as it nears the sun.
Halley's Comet becomes visible to the unaided eye about every 76 years as it nears the sun.
The idea of nearby stars influencing comets goes back to 1950, when the astronomer Jan Hendrik Oort hypothesized an invisible repository of comets - the so-called Oort cloud - swarming around the solar system out to a distance of 100,000 AU (one AU is the distance between the sun and the Earth).
Oort assumed that stars passing through the cloud would cause a fresh batch of comets to fall in towards the sun, where they become visible to astronomers. Such a disturbance could have long term effects.
"The comets we see now could be from a stellar passage hundreds of millions of years ago," said Hans Rickman of the Uppsala Astronomical Observatory in Sweden.
However, Rickman and his colleagues have confirmed that star encounters alone cannot explain comet behavior. Using a computer model of the Oort cloud, they show that gravity effects from the galaxy are equally important. The results are reported in a recent article in the journal Celestial Mechanics and Dynamical Astronomy.
Two stars passing in the night
Although Earth has almost certainly been hit by comets throughout its history, it is not all that clear how often that has happened. Much of the crater history on Earth has been erased because of erosion or tectonic activity. The remaining craters could have come from asteroids instead of comets.
"It's quite difficult to tell a comet-induced crater from an asteroid one, since the impactor gets essentially vaporized," Rickman said.
© Unknown
What our Milky Way Galaxy may look like from above, and the position of our star, the sun, within the galaxy. The gravitational influence of the galaxy may disrupt the Oort Cloud of comets that surrounds our solar system.
What our Milky Way Galaxy may look like from above, and the position of our star, the sun, within the galaxy. The gravitational influence of the galaxy may disrupt the Oort Cloud of comets that surrounds our solar system.
Comet impacts are, however, likely to be more energetic (and therefore more damaging), since comets are moving much faster than asteroids when they pass by Earth.
Comet orbits can be altered whenever another star comes within 10,000 AU of our sun. Such a close encounter - occurring every 100 million years or so - will not typically disturb asteroids or planets, but it definitely "shakes up the whole Oort cloud," Rickman said.
Most scientists have presumed that these star crossings will lead to a shower of comets raining down on the Earth and the rest of the inner solar system. Some have even claimed to find evidence of periodic mass extinctions that might be explained by a single (as-yet-unidentified) star in an elliptical orbit around the sun.
To study the effect of stellar perturbations, Rickman and his colleagues model the Oort cloud with a sample of one million comets (the true number of cloud comets is unknown, but certainly much higher). The simulations are allowed to run for a time period corresponding to the 5-billion-year age of the solar system.
The results show that stars can induce comet showers, but the contrast with non-shower periods is less than what people have thought before, Rickman said. This leveling out in comet activity is due to the influence of the gravitational field of the Milky Way.
Galactic tide
© Southwest Research Institute
Diagram showing the position of the Oort Cloud.
Diagram showing the position of the Oort Cloud.
The simulations by Rickman and colleagues show how the galactic tide constantly gives a small nudge to the cloud's comets. Some of these comets are in rather unstable orbits to begin with, so the slight push can send them on a sun-bound trajectory. Eventually, however, all these unstable comets are ejected from the solar system.
And this is where stellar encounters become important. They scramble the Oort cloud, so that the galactic tide has a new crop of unstable comets to funnel into the inner solar system.
"The general picture spawned by our results is that injection of comets from the Oort Cloud is essentially to be seen as a team work involving both tides and stars," the scientists write in their paper.
This star-tide collaboration keeps a relatively steady supply of comets zooming nearby, so the threat from comet impacts probably does not change much over time.
Comment: Have you read Cosmic Turkey Shoot?
Fri, 12 Dec 2008 17:59 UTC
Space Weather
The annual Geminid meteor shower peaks on Dec. 13th and Dec. 14th when
Earth passes through a stream of debris from extinct comet 3200
Phaethon. Bright moonlight will reduce the number of visible meteors
from the usual 100/hr to only 20/hr or so. That's still a nice show.
For best results, watch the sky starting 10 pm local time on Saturday night (Dec 13th) until dawn on Sunday morning (Dec. 14th). [live updates]
For best results, watch the sky starting 10 pm local time on Saturday night (Dec 13th) until dawn on Sunday morning (Dec. 14th). [live updates]
Jana Peterson
Budgeteer News
Fri, 12 Dec 2008 00:35 UTC
There are side benefits to creating a massive light display on Park
Point. In this case, it meant Marcia and Zach Hales were outside at
Park Point, looking toward the lake, on the night of Nov. 26.
The grandmother and grandson saw a bright white ball with a multi-colored vapor tail trailing behind it shoot across the sky from south to north. Zach says it disappeared over the horizon; Marcia thought it dropped into the lake.
It turns out they weren't the only ones to spot the fireball.
After reading a notice about the sighting in last week's issue of the Budgeteer, Susie Johnson said she saw the same thing, only from a different location (she lives in Duluth Heights).
"I was looking out my window to the east when I saw [the ball] go by," she said. "It seemed so low, I thought for sure it was going to crash to the ground. In my estimation at that time, I thought it would hit somewhere around the Arrowhead Road area.
"I'm glad to know others saw it too, it was quite a sight! It was beautiful, however, a little scary, too, thinking it was going to crash into something."
Wally Jordan, a railroad engineer, was working at Rice's point that night, moving railroad cars with a co-worker.
"In all my years, it has to be the brightest falling star I ever saw," Jordan said. "At first I thought, Wow, somebody's got a lot of money to be setting off fireworks like that."
These Northlanders weren't the only ones to spot the impressive meteor.
According to the Fireball Sightings Log on the American Meteor Society Web site there were 19 different reports of a fireball between 8:50 and 9 p.m. that night. Nine of those reports were filed from Wisconsin, including folks in Iron River and Hayward, and six were from Minnesota. People in Indiana and Illinois also reported seeing a fireball with a white head and green tail, or green and blue streaks.
Observers on the AMS site ranked the magnitude of the Nov. 26 fireball between -13 and -27, with -13 equivalent to the light produced by the full moon, and -27 equivalent to the light produced by the sun.
Six days before that, a massive fireball lit up the Canadian sky - that meteor's image was even captured by a police officer's dash camera.
It seems likely that the fireball sightings have something to do with the Geminid meteor showers. According to analysis of meteor video data by Sirko Molau cited on transient sky.wordpress.com, the Geminids are active for almost an entire month, between the dates of Nov. 23 and Dec. 21.
"It was something I'll never forget," Jordan said. "The tail, it was so bright, it lit up the whole sky. It lasted for awhile, too."
Keep your eyes on the sky
This weekend will see one of the year's better meteor showers: the Geminids. According to MeteorShowersOnline.com, this year's Geminid meteor shower is supposed to peak Dec. 13 and 14. This year, because of the full moon, people will likely spot fewer meteors, but experts estimate folks could still see between 10 and 30 per hour. If you are willing to brave the cold, the Geminids are one of the easier showers to observe because you don't have to stay up until the wee hours of the morning to see them. The Geminids can be seen in good numbers as early as 10 p.m. and are great anytime after midnight. The Geminids will appear to radiate from the constellation of Gemini near the bright star Castor.
The grandmother and grandson saw a bright white ball with a multi-colored vapor tail trailing behind it shoot across the sky from south to north. Zach says it disappeared over the horizon; Marcia thought it dropped into the lake.
It turns out they weren't the only ones to spot the fireball.
After reading a notice about the sighting in last week's issue of the Budgeteer, Susie Johnson said she saw the same thing, only from a different location (she lives in Duluth Heights).
"I was looking out my window to the east when I saw [the ball] go by," she said. "It seemed so low, I thought for sure it was going to crash to the ground. In my estimation at that time, I thought it would hit somewhere around the Arrowhead Road area.
"I'm glad to know others saw it too, it was quite a sight! It was beautiful, however, a little scary, too, thinking it was going to crash into something."
Wally Jordan, a railroad engineer, was working at Rice's point that night, moving railroad cars with a co-worker.
"In all my years, it has to be the brightest falling star I ever saw," Jordan said. "At first I thought, Wow, somebody's got a lot of money to be setting off fireworks like that."
These Northlanders weren't the only ones to spot the impressive meteor.
According to the Fireball Sightings Log on the American Meteor Society Web site there were 19 different reports of a fireball between 8:50 and 9 p.m. that night. Nine of those reports were filed from Wisconsin, including folks in Iron River and Hayward, and six were from Minnesota. People in Indiana and Illinois also reported seeing a fireball with a white head and green tail, or green and blue streaks.
Observers on the AMS site ranked the magnitude of the Nov. 26 fireball between -13 and -27, with -13 equivalent to the light produced by the full moon, and -27 equivalent to the light produced by the sun.
Six days before that, a massive fireball lit up the Canadian sky - that meteor's image was even captured by a police officer's dash camera.
It seems likely that the fireball sightings have something to do with the Geminid meteor showers. According to analysis of meteor video data by Sirko Molau cited on transient sky.wordpress.com, the Geminids are active for almost an entire month, between the dates of Nov. 23 and Dec. 21.
"It was something I'll never forget," Jordan said. "The tail, it was so bright, it lit up the whole sky. It lasted for awhile, too."
Keep your eyes on the sky
This weekend will see one of the year's better meteor showers: the Geminids. According to MeteorShowersOnline.com, this year's Geminid meteor shower is supposed to peak Dec. 13 and 14. This year, because of the full moon, people will likely spot fewer meteors, but experts estimate folks could still see between 10 and 30 per hour. If you are willing to brave the cold, the Geminids are one of the easier showers to observe because you don't have to stay up until the wee hours of the morning to see them. The Geminids can be seen in good numbers as early as 10 p.m. and are great anytime after midnight. The Geminids will appear to radiate from the constellation of Gemini near the bright star Castor.
Christian Godoy Rivera
El Mercurio
Sat, 13 Dec 2008 02:14 UTC
Panic among the population. Some affirm that the sky was illuminated for long minutes.
Some witnesses say that there were several explosions, others assure that the sky was so illuminated as the dawn for long minutes. The only thing that is certain is that a general blackout occured in the all of the north sector of the city and provoked chaos among the community.
Telephonic calls from the neighbors to El Mercurio newspaper showed the terror caused by the incident, which happened around 11 p.m.. Some declared that there were meteorites, lightnings and comets passing nearby, other that there were ufos.
Other people affirmed that a troublesome buzz accompanied the blackout.
In addition it was unofficially informed that personal of Elecda (Electrical Company Of Antofagasta) found in the road to the graveyard Park of the Memory, some electrical layings cut, but without any confirmation of what it happened.
Some witnesses say that there were several explosions, others assure that the sky was so illuminated as the dawn for long minutes. The only thing that is certain is that a general blackout occured in the all of the north sector of the city and provoked chaos among the community.
Telephonic calls from the neighbors to El Mercurio newspaper showed the terror caused by the incident, which happened around 11 p.m.. Some declared that there were meteorites, lightnings and comets passing nearby, other that there were ufos.
Other people affirmed that a troublesome buzz accompanied the blackout.
In addition it was unofficially informed that personal of Elecda (Electrical Company Of Antofagasta) found in the road to the graveyard Park of the Memory, some electrical layings cut, but without any confirmation of what it happened.
News 2
Wed, 17 Dec 2008 21:56 UTC
A number of people in the Lowcountry called News 2 to tell us about "a boom" they heard early Sunday afternoon.
Most of them live along the coast.
There is something known as the Seneca Guns.
It's the theory that there are cracks in the ocean floor and when gas escapes from those cracks, it causes a boom.
Nobody knows for sure if that's what happened.
However, a James Island woman insisted to News 2 that she felt an earthquake because her house shook.
So we asked a College of Charleston geology professor if the boom could be related to Tuesday's earthquake.
Steven Jaume, an assistant geology professor at the College of Charleston, told News 2 that he doesn't believe the two were connected.
"Generally you hear something," said Jaume, "you're talking about a sonic boom. So it's something in the atmosphere. It would not be connected to an earthquake. The big difference obviously is with an earthquake you feel them then you may hear things rattling. You generally don't hear the earthquake. A sonic boom is something caused through the air. People will hear them very clearly and their wave may actually rattle the house. I wouldn't find any connection (to an earthquake)."
Most of them live along the coast.
There is something known as the Seneca Guns.
It's the theory that there are cracks in the ocean floor and when gas escapes from those cracks, it causes a boom.
Nobody knows for sure if that's what happened.
However, a James Island woman insisted to News 2 that she felt an earthquake because her house shook.
So we asked a College of Charleston geology professor if the boom could be related to Tuesday's earthquake.
Steven Jaume, an assistant geology professor at the College of Charleston, told News 2 that he doesn't believe the two were connected.
"Generally you hear something," said Jaume, "you're talking about a sonic boom. So it's something in the atmosphere. It would not be connected to an earthquake. The big difference obviously is with an earthquake you feel them then you may hear things rattling. You generally don't hear the earthquake. A sonic boom is something caused through the air. People will hear them very clearly and their wave may actually rattle the house. I wouldn't find any connection (to an earthquake)."
Perth Now
Thu, 18 Dec 2008 00:30 UTC
West Australia was treated to a rare show last night as a meteor blazed across the sky between Perth and the Goldfields.
Perth Observatory received dozens of reports of blue, green and orange lights in the sky between Perth and Leonora and east to Kalgoorlie just before 8.30pm.
Experts say the fireball was probably a meteor -- about the size of a cricket ball -- burning up as it passed through Earth's atmosphere.
Perth Observatory astronomer Ralph Martin said the meteor was spotted about 8.25pm -- just before sunset -- as it hurtled in a south-to-north direction across the southern half of WA at a speed of about 20km per second.
Mr Martin said some callers reported seeing a "blueish flash'' as the meteor streaked across the sky. Most people only glimpsed the phenomenon for "two to three seconds.''
The Observatory received reports from Perth, through the Wheatbelt towns of Beacon, Bolgart and Toodyay, out to Kalgoorlie.
One man from Kalgoorlie rang to check what it was, thinking it could have been a safety flare set off in an emergency.
"It came over about 8.25pm,'' Mr Martin said. "People reported a bright blueish flash and then a streak coming out out of it, some people said they saw a trail of light.''
"It was twilight, there were no stars. Had it been dark, it would have been awfully bright.
"Because they travel so fast people will only see them for a couple of seconds.''
Mr Martin said WA probably experiences several meteor events a year, but because they are extremely quick they are not seen by many people.
Numerous
reports of a large fireball in the sky were called into 911 dispatchers
and our NewsChannel 5 newsroom Thursday evening.
Viewers reported a large green and blue fireball falling from the southern sky around 4:55pm.
Initial reports were a possible plane on fire in the sky but law enforcement officials confirmed no reports of aircrafts down.
Local astronomers believe it was a fireball, which is bigger and brighter than an average meteor.
There were no reports it made impact into the ground, which would be a meteorite.
The Geminids Meteor showers usually peak around this time of year and can be viewed to the east late at night.
If you have videos or photos you would like to share with NewsChannel 5, you can call our newsroom at (561) 653-5700 and email us at NewsTips@wptv.com
Perth Observatory received dozens of reports of blue, green and orange lights in the sky between Perth and Leonora and east to Kalgoorlie just before 8.30pm.
Experts say the fireball was probably a meteor -- about the size of a cricket ball -- burning up as it passed through Earth's atmosphere.
Perth Observatory astronomer Ralph Martin said the meteor was spotted about 8.25pm -- just before sunset -- as it hurtled in a south-to-north direction across the southern half of WA at a speed of about 20km per second.
Mr Martin said some callers reported seeing a "blueish flash'' as the meteor streaked across the sky. Most people only glimpsed the phenomenon for "two to three seconds.''
The Observatory received reports from Perth, through the Wheatbelt towns of Beacon, Bolgart and Toodyay, out to Kalgoorlie.
One man from Kalgoorlie rang to check what it was, thinking it could have been a safety flare set off in an emergency.
"It came over about 8.25pm,'' Mr Martin said. "People reported a bright blueish flash and then a streak coming out out of it, some people said they saw a trail of light.''
"It was twilight, there were no stars. Had it been dark, it would have been awfully bright.
"Because they travel so fast people will only see them for a couple of seconds.''
Mr Martin said WA probably experiences several meteor events a year, but because they are extremely quick they are not seen by many people.
WPTV
Thu, 18 Dec 2008 00:25 UTC
© Paul Skywarn
December 17th Meteor
December 17th Meteor
Viewers reported a large green and blue fireball falling from the southern sky around 4:55pm.
Initial reports were a possible plane on fire in the sky but law enforcement officials confirmed no reports of aircrafts down.
Local astronomers believe it was a fireball, which is bigger and brighter than an average meteor.
There were no reports it made impact into the ground, which would be a meteorite.
The Geminids Meteor showers usually peak around this time of year and can be viewed to the east late at night.
If you have videos or photos you would like to share with NewsChannel 5, you can call our newsroom at (561) 653-5700 and email us at NewsTips@wptv.com
Robert S. Boyd
McClatchy Newspapers
Thu, 18 Dec 2008 15:46 UTC
A blue-ribbon panel of scientists is trying to determine the best way
to detect and ward off any wandering space rocks that might be on a
collision course with Earth.
''We're looking for the killer asteroid,'' James Heasley , of the University of Hawaii's Institute for Astronomy , last week told the committee that the National Academy of Sciences created at Congress' request.
Congress asked the academy to conduct the study after astronomers were unable to eliminate an extremely slight chance that an asteroid called Apophis will slam into Earth with devastating effect in 2036.
Apophis was discovered in 2004 about 17 million miles from Earth on a course that would overlap our planet's orbit in 2029 and return seven years later. Observers said that the asteroid - a massive boulder left over from the birth of the solar system - is about 1,000 feet wide and weighs at least 50 million tons.
After further observations, astronomers reported that the asteroid would skim by Earth harmlessly in 2029, but it has a one in 44,000 probability of slamming into our planet on Easter Sunday , April 13, 2036 .
Small changes in Apophis' path that could make the difference between a hit or a miss are possible, according to Jon Giorgini , a planetary analyst in NASA's Jet Propulsion Laboratory in Pasadena, Calif.
''We have not eliminated the threat in 2036,'' Lindley Johnson , the manager of NASA's asteroid detection program, told the committee.
The academy panel is headed by Irwin Shapiro , a former director of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. It has a two-part assignment from Congress : Detect and deflect asteroids that might hit earth.
First, the Shapiro committee is supposed to propose the best way to detect and analyze 90 percent of the so-called ''near Earth objects'' orbiting between Mars and Venus that are wider than 460 feet by 2020.
About 20 percent of these are identified as potentially hazardous objects because they might pass within 5 million miles of Earth (20 times the distance to the Moon).
More than 5,000 near Earth objects, including 789 potentially hazardous objects, have been identified so far. Johnson predicted that future surveys will find at least 66,000 near Earth objects and 18,000 potentially hazardous objects.
A collision with one or more of these many objects littering the solar system is inevitable, Johnson said. ''Once every hundred years there might be something to worry about, but it could happen tomorrow.''
For example, astronomers had only 24 hours' notice of a small asteroid that blew up over northern Africa on Oct. 7 . A larger, more dangerous object presumably would be spotted years or decades ahead, giving humans time to change its course before it hit.
The Shapiro panel's second task is to review various methods that have been proposed to deflect or destroy an incoming asteroid and recommend the best options. They include a nuclear bomb, conventional explosives or a spacecraft that would push or pull the asteroid off its course.
Offbeat ideas are painting the surface of the asteroid so that the sun's rays would heat it differently and alter its direction, and a ''gravity tractor, ''a satellite that would fly close to the asteroid, gently nudging it aside.
The earlier that a dangerous asteroid is found, and the farther it is from Earth, the easier it will be to change its trajectory, panel members were told. A relatively small force would be enough while the object is millions of miles away.
The year 2029 could be crucial. When Apophis makes its first pass by Earth, its track can be more precisely determined. That will enable astronomers to judge whether Earth will escape with a near miss or will have to take swift action to avoid a blow that could devastate a region as large as Europe or the Eastern United States .
To deflect an asteroid, scientists need to know its shape, weight and composition. A ball of loose rubble would be handled differently from a solid metallic rock.
''Finding them is one thing, but you have to know your enemy,'' said James Green , the director of NASA's Planetary Science Division.
So far, NASA has spent $41 million on asteroid detection and deflection, but the Near Earth Object Program is running out of money.
''It's just barely hanging on,'' Shapiro said.
Two expensive telescopes to focus on dangerous asteroids have been proposed, but Congress and the incoming Obama administration must be persuaded to approve the money.
''Without new telescopes, we'd never get to 90 percent (detection),'' Johnson said.
After a lot of original skepticism, Congress now looks favorably on the asteroid project, according to Richard Obermann , the staff director of the House Subcommittee on Space and Aeronautics.
''There used to be a high giggle factor among members,'' Obermann said. ''But it's now a very respectable area of investigation.''
Johnson told the Shapiro committee that the search for killer asteroids must have a high priority.
''The space program could provide humanity few greater legacies than to know the time and place of any cosmic destruction to allow ample time to prepare our response to that inevitable event,'' he said.
''We're looking for the killer asteroid,'' James Heasley , of the University of Hawaii's Institute for Astronomy , last week told the committee that the National Academy of Sciences created at Congress' request.
Congress asked the academy to conduct the study after astronomers were unable to eliminate an extremely slight chance that an asteroid called Apophis will slam into Earth with devastating effect in 2036.
Apophis was discovered in 2004 about 17 million miles from Earth on a course that would overlap our planet's orbit in 2029 and return seven years later. Observers said that the asteroid - a massive boulder left over from the birth of the solar system - is about 1,000 feet wide and weighs at least 50 million tons.
After further observations, astronomers reported that the asteroid would skim by Earth harmlessly in 2029, but it has a one in 44,000 probability of slamming into our planet on Easter Sunday , April 13, 2036 .
Small changes in Apophis' path that could make the difference between a hit or a miss are possible, according to Jon Giorgini , a planetary analyst in NASA's Jet Propulsion Laboratory in Pasadena, Calif.
''We have not eliminated the threat in 2036,'' Lindley Johnson , the manager of NASA's asteroid detection program, told the committee.
The academy panel is headed by Irwin Shapiro , a former director of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. It has a two-part assignment from Congress : Detect and deflect asteroids that might hit earth.
First, the Shapiro committee is supposed to propose the best way to detect and analyze 90 percent of the so-called ''near Earth objects'' orbiting between Mars and Venus that are wider than 460 feet by 2020.
About 20 percent of these are identified as potentially hazardous objects because they might pass within 5 million miles of Earth (20 times the distance to the Moon).
More than 5,000 near Earth objects, including 789 potentially hazardous objects, have been identified so far. Johnson predicted that future surveys will find at least 66,000 near Earth objects and 18,000 potentially hazardous objects.
A collision with one or more of these many objects littering the solar system is inevitable, Johnson said. ''Once every hundred years there might be something to worry about, but it could happen tomorrow.''
For example, astronomers had only 24 hours' notice of a small asteroid that blew up over northern Africa on Oct. 7 . A larger, more dangerous object presumably would be spotted years or decades ahead, giving humans time to change its course before it hit.
The Shapiro panel's second task is to review various methods that have been proposed to deflect or destroy an incoming asteroid and recommend the best options. They include a nuclear bomb, conventional explosives or a spacecraft that would push or pull the asteroid off its course.
Offbeat ideas are painting the surface of the asteroid so that the sun's rays would heat it differently and alter its direction, and a ''gravity tractor, ''a satellite that would fly close to the asteroid, gently nudging it aside.
The earlier that a dangerous asteroid is found, and the farther it is from Earth, the easier it will be to change its trajectory, panel members were told. A relatively small force would be enough while the object is millions of miles away.
The year 2029 could be crucial. When Apophis makes its first pass by Earth, its track can be more precisely determined. That will enable astronomers to judge whether Earth will escape with a near miss or will have to take swift action to avoid a blow that could devastate a region as large as Europe or the Eastern United States .
To deflect an asteroid, scientists need to know its shape, weight and composition. A ball of loose rubble would be handled differently from a solid metallic rock.
''Finding them is one thing, but you have to know your enemy,'' said James Green , the director of NASA's Planetary Science Division.
So far, NASA has spent $41 million on asteroid detection and deflection, but the Near Earth Object Program is running out of money.
''It's just barely hanging on,'' Shapiro said.
Two expensive telescopes to focus on dangerous asteroids have been proposed, but Congress and the incoming Obama administration must be persuaded to approve the money.
''Without new telescopes, we'd never get to 90 percent (detection),'' Johnson said.
After a lot of original skepticism, Congress now looks favorably on the asteroid project, according to Richard Obermann , the staff director of the House Subcommittee on Space and Aeronautics.
''There used to be a high giggle factor among members,'' Obermann said. ''But it's now a very respectable area of investigation.''
Johnson told the Shapiro committee that the search for killer asteroids must have a high priority.
''The space program could provide humanity few greater legacies than to know the time and place of any cosmic destruction to allow ample time to prepare our response to that inevitable event,'' he said.
Fri, 19 Dec 2008 21:06 UTC
MSNBC
Numerous people reported seeing a big orange fireball with a green
trail falling out of the sky in Palm Beach County on Thursday at about
5 p.m.
"It looked like a falling star," said Cindy Abath, who was traveling on Congress Avenue.
Chad Alvarez said he had just finished surfing Thursday evening on Palm Beach and saw the fireball stream through the sky.
"It looked kind of like a firework, but it was coming down from the sky and it was a really beautiful color," he said. "It was like an aqua-iridescent orangeish color. It was really beautiful. It was a color I've really never seen before."
Hundreds reported seeing the fireball heading east over Palm Beach County.
"I just looked at it, I know this can't be no star falling out the sky like this here," a resident said. "It was something different. I was looking for it to hit the ground and explode or something."
A Federal Aviation Administration spokeswoman said she was being told the object was a meteor from a shower.
"It sounds like a bolide," said Elizabeth Dashiell with the South Florida Science Museum.
Dashiell said bolides are usually only visible at night but can be seen in daylight when they burn through the atmosphere.
Alvarez said he knows he's lucky to have seen the bolide.
"No, I won't forget it," he said. "It's something you see, and I think it stays with you a while or a long time."
Anyone with pictures of the object is asked to send them to WPBF.com
© MSNBC
"It looked like a falling star," said Cindy Abath, who was traveling on Congress Avenue.
Chad Alvarez said he had just finished surfing Thursday evening on Palm Beach and saw the fireball stream through the sky.
"It looked kind of like a firework, but it was coming down from the sky and it was a really beautiful color," he said. "It was like an aqua-iridescent orangeish color. It was really beautiful. It was a color I've really never seen before."
Hundreds reported seeing the fireball heading east over Palm Beach County.
"I just looked at it, I know this can't be no star falling out the sky like this here," a resident said. "It was something different. I was looking for it to hit the ground and explode or something."
A Federal Aviation Administration spokeswoman said she was being told the object was a meteor from a shower.
"It sounds like a bolide," said Elizabeth Dashiell with the South Florida Science Museum.
Dashiell said bolides are usually only visible at night but can be seen in daylight when they burn through the atmosphere.
Alvarez said he knows he's lucky to have seen the bolide.
"No, I won't forget it," he said. "It's something you see, and I think it stays with you a while or a long time."
Anyone with pictures of the object is asked to send them to WPBF.com
Joe Rao
Space.com
Fri, 19 Dec 2008 11:10 UTC
For meteor observers, the presence of an almost-full Moon cast a bright
pall on this month's performance of the Geminid Meteor Shower, normally
one of the best meteor displays of the year. But for a wild card,
another very good meteor shower may be right around corner. And for
this one, the Moon will not play a factor at all.
So, get out your 2009 calendar and put a big circle around Saturday morning, Jan. 3.
That's the expected peak date for the Quadrantids, a notoriously unpredictable meteor display. In 2009, peak activity is due to occur in the pre-dawn hours of Jan. 3 and will strongly favor western North America. If the "Quads" reach their full potential, observers blessed with clear, dark skies could be averaging one or two meteor sightings per minute in the hour or two prior to the break of dawn.
The Quadrantid (pronounced KWA-dran-tid) meteors provides one of the most intense annual meteor displays, with a brief, sharp maximum lasting but a few hours. Adolphe Quetelet of Brussels Observatory discovered the shower in the 1830's, and shortly afterward it was noted by several other astronomers in Europe and America.
The meteors are named after the obsolete constellation Quadrans Muralis the Mural or Wall Quadrant (an astronomical instrument), depicted in some 19th-century star atlases roughly midway between the end of the handle of the Big Dipper and the quadrilateral of stars marking the head of the constellation Draco. (The International Astronomical Union phased out Quadrans Muralis in 1922.)
Usually difficult to see
Unfortunately, many factors combine to make the peak of this display difficult to observe on a regular basis.
* Peak intensity is exceedingly sharp: meteor rates exceed one-half of their highest value for only about 8 hours (compared to two days for the August Perseids). This means that the stream of particles that produce this shower is a narrow one - apparently derived within the last 500-years from a small comet. The parentage of the Quadrantids had long been a mystery. Then Dr. Peter Jenniskens, an astronomer at the SETI Institute in Mountain View, Calif., noticed that the orbit of 2003 EH1 - a small asteroid discovered in March 2003 - ''falls snug in the shower.'' He believes that this 1.2 mi. (2 km.) chunk of rock is the source of the Quadrantids; possibly this asteroid is the burnt out core of the lost comet C/1490 Y1.
* As viewed from mid-northern latitudes, we have to get up before dawn to see the Quadrantids at their best. This is because the radiant - that part of the sky from where the meteors to emanate - is down low on the northern horizon until about midnight, rising slowly higher as the night progresses. The growing light of dawn ends meteor observing usually by around 7 a.m. So, if the "Quads" are to be seen at all, some part of that 8-hour active period must fall between 2 and 7 a.m.
* In one out of every three years, bright moonlight spoils the view.
* Over northern latitudes, early January often sees inclement/unsettled weather.
It is not surprising then, that the Quadrantids are not as well-observed as some of the other annual meteor showers, but 2009 could be an exception.
Excellent prospects in 2009
According to the International Meteor Organization, maximum activity this year is expected on 4:50 a.m. Pacific Standard Time on Jan. 3. For those across the western half of the United States and Canada, the radiant will soar high in the eastern sky just prior to the onset of morning twilight. Over the eastern United States and Canada, the spike of activity is predicted to come after sunrise.
Quadrantid meteors are described as bright and bluish with long silvery trains. Some years produce a mere handful, but for favorably placed observers, an excellent meteor display may be in the offing; at greatest activity, Quadrantid rates will likely range from 30 to 60 per hour for eastern parts of the U.S. and Canada, to perhaps 60 to 120 per hour for the western United States and Canada. For those in Europe, the shower's sharp peak will likely come long after sunrise. Nonetheless, hourly rates of perhaps 15 to 30 may still be seen.
As far as the moon is concerned, it will not be a factor at all this year. It's a waxing crescent, two days from first quarter phase and will have set around 11 p.m. local time on Friday, Jan. 2, leaving the rest of the night dark for meteor watching.
So, get out your 2009 calendar and put a big circle around Saturday morning, Jan. 3.
That's the expected peak date for the Quadrantids, a notoriously unpredictable meteor display. In 2009, peak activity is due to occur in the pre-dawn hours of Jan. 3 and will strongly favor western North America. If the "Quads" reach their full potential, observers blessed with clear, dark skies could be averaging one or two meteor sightings per minute in the hour or two prior to the break of dawn.
The Quadrantid (pronounced KWA-dran-tid) meteors provides one of the most intense annual meteor displays, with a brief, sharp maximum lasting but a few hours. Adolphe Quetelet of Brussels Observatory discovered the shower in the 1830's, and shortly afterward it was noted by several other astronomers in Europe and America.
The meteors are named after the obsolete constellation Quadrans Muralis the Mural or Wall Quadrant (an astronomical instrument), depicted in some 19th-century star atlases roughly midway between the end of the handle of the Big Dipper and the quadrilateral of stars marking the head of the constellation Draco. (The International Astronomical Union phased out Quadrans Muralis in 1922.)
Usually difficult to see
Unfortunately, many factors combine to make the peak of this display difficult to observe on a regular basis.
* Peak intensity is exceedingly sharp: meteor rates exceed one-half of their highest value for only about 8 hours (compared to two days for the August Perseids). This means that the stream of particles that produce this shower is a narrow one - apparently derived within the last 500-years from a small comet. The parentage of the Quadrantids had long been a mystery. Then Dr. Peter Jenniskens, an astronomer at the SETI Institute in Mountain View, Calif., noticed that the orbit of 2003 EH1 - a small asteroid discovered in March 2003 - ''falls snug in the shower.'' He believes that this 1.2 mi. (2 km.) chunk of rock is the source of the Quadrantids; possibly this asteroid is the burnt out core of the lost comet C/1490 Y1.
* As viewed from mid-northern latitudes, we have to get up before dawn to see the Quadrantids at their best. This is because the radiant - that part of the sky from where the meteors to emanate - is down low on the northern horizon until about midnight, rising slowly higher as the night progresses. The growing light of dawn ends meteor observing usually by around 7 a.m. So, if the "Quads" are to be seen at all, some part of that 8-hour active period must fall between 2 and 7 a.m.
* In one out of every three years, bright moonlight spoils the view.
* Over northern latitudes, early January often sees inclement/unsettled weather.
It is not surprising then, that the Quadrantids are not as well-observed as some of the other annual meteor showers, but 2009 could be an exception.
Excellent prospects in 2009
According to the International Meteor Organization, maximum activity this year is expected on 4:50 a.m. Pacific Standard Time on Jan. 3. For those across the western half of the United States and Canada, the radiant will soar high in the eastern sky just prior to the onset of morning twilight. Over the eastern United States and Canada, the spike of activity is predicted to come after sunrise.
Quadrantid meteors are described as bright and bluish with long silvery trains. Some years produce a mere handful, but for favorably placed observers, an excellent meteor display may be in the offing; at greatest activity, Quadrantid rates will likely range from 30 to 60 per hour for eastern parts of the U.S. and Canada, to perhaps 60 to 120 per hour for the western United States and Canada. For those in Europe, the shower's sharp peak will likely come long after sunrise. Nonetheless, hourly rates of perhaps 15 to 30 may still be seen.
As far as the moon is concerned, it will not be a factor at all this year. It's a waxing crescent, two days from first quarter phase and will have set around 11 p.m. local time on Friday, Jan. 2, leaving the rest of the night dark for meteor watching.
CTV.ca
Mon, 22 Dec 2008 19:17 UTC
The sheer number of meteorite fragments that touched down on Nov. 20 in
Saskatchewan -- first lighting up the sky in a dramatic light show
witnessed by people across the prairies -- may have set a new Canadian
record.
Rather than just one space rock hitting the ground, as first thought, the bounty appears to consist of thousands of meteorite fragments, according to the team that has co-ordinated the recovery.
The group, organized by the University of Calgary, has recovered more than 100 meteorites from the site southwest of Lloydminster, on the border of Alberta and Saskatchewan, and says many more are still out there.
Volunteer searcher Ellen Milley, who is pursuing her master's at the University of Calgary's geoscience department, found the first meteorite fragments on Nov. 27.
U of C planetary scientist Alan Hildebrand said in a written statement there are roughly 2,000 meteorites of 10 grams or more, per square kilometre, in the northern part of the field where the fragments were found.
Altogether, he calculated, there are likely more than 10,000 meteorites on the ground in the area.
"The last day that the search teams were out, it snowed all day and we still found five meteorites which is ridiculous. It shows just how many are out there," Hildebrand said.
The area where the meteorites were discovered is being called Buzzard Coulee, after a valley near the hamlet of Lone Rock, Sask., where Milley found the first fragments.
The largest meteor fall previously on record occurred when hundreds of fragments were recovered near Bruderheim, Alta. in 1960.
Hildebrand said the November event could easily surpass those numbers.
"I think that the number of individual meteorites that will be recovered for Buzzard Coulee will easily set the Canadian record for the largest fall recovery, but we still don't know how big the biggest meteorite out there is, so we don't know how much mass we can expect to be recovered of the approximately 1 tonne that fell," Hildebrand said.
A large-scale search will be held in the spring, prior to the start of cultivation and seeding, to recover as many meteorites as possible, Hildebrand said.
He said the initiative planned for spring will be "the biggest meteorite search effort that Canada has ever seen."
Scientists are still examining the fragments in an attempt to learn more about where the meteor came from. It has already been classified as an H4 type.
The rock is on the low end of the H4 scale, meaning it didn't experience high heat on its parent asteroid.
"The meteorite also appears to show that different types of material are mixed together in a subtle way, but we will have to study more thin sections to better understand this," said Dr. Melinda Hutson, a Canadian scientist at Cascadia Meteorite Laboratory at Portlant State University who helped classify the meteorite.
"The meteorite is slightly shocked, so the material was possibly stirred by an impact on its parent asteroid."
Rather than just one space rock hitting the ground, as first thought, the bounty appears to consist of thousands of meteorite fragments, according to the team that has co-ordinated the recovery.
The group, organized by the University of Calgary, has recovered more than 100 meteorites from the site southwest of Lloydminster, on the border of Alberta and Saskatchewan, and says many more are still out there.
Volunteer searcher Ellen Milley, who is pursuing her master's at the University of Calgary's geoscience department, found the first meteorite fragments on Nov. 27.
U of C planetary scientist Alan Hildebrand said in a written statement there are roughly 2,000 meteorites of 10 grams or more, per square kilometre, in the northern part of the field where the fragments were found.
Altogether, he calculated, there are likely more than 10,000 meteorites on the ground in the area.
"The last day that the search teams were out, it snowed all day and we still found five meteorites which is ridiculous. It shows just how many are out there," Hildebrand said.
The area where the meteorites were discovered is being called Buzzard Coulee, after a valley near the hamlet of Lone Rock, Sask., where Milley found the first fragments.
The largest meteor fall previously on record occurred when hundreds of fragments were recovered near Bruderheim, Alta. in 1960.
Hildebrand said the November event could easily surpass those numbers.
"I think that the number of individual meteorites that will be recovered for Buzzard Coulee will easily set the Canadian record for the largest fall recovery, but we still don't know how big the biggest meteorite out there is, so we don't know how much mass we can expect to be recovered of the approximately 1 tonne that fell," Hildebrand said.
A large-scale search will be held in the spring, prior to the start of cultivation and seeding, to recover as many meteorites as possible, Hildebrand said.
He said the initiative planned for spring will be "the biggest meteorite search effort that Canada has ever seen."
Scientists are still examining the fragments in an attempt to learn more about where the meteor came from. It has already been classified as an H4 type.
The rock is on the low end of the H4 scale, meaning it didn't experience high heat on its parent asteroid.
"The meteorite also appears to show that different types of material are mixed together in a subtle way, but we will have to study more thin sections to better understand this," said Dr. Melinda Hutson, a Canadian scientist at Cascadia Meteorite Laboratory at Portlant State University who helped classify the meteorite.
"The meteorite is slightly shocked, so the material was possibly stirred by an impact on its parent asteroid."
Somerset Reporter
Tue, 23 Dec 2008 11:08 UTC
Steven Jeffrey Ostro, a senior research NASA scientist who pioneered
the field of asteroid radar astronomy, died on December 15 at age 62,
following a two and a half year battle with cancer.
Dr. Ostro was a New Jersey native who earned bachelor's degrees in liberal arts and ceramic science from Rutgers University; a master's degree in engineering physics from Cornell University; and a doctorate in planetary sciences from the Massachusetts Institute of Technology. Beginning in 1979 - after a personal invitation from Carl Sagan - Dr. Ostro served as an assistant professor at Cornell University. In 1984, he began creating his life's legacy through his work at NASA's Jet Propulsion Laboratory in Pasadena, California.
Essentially, Dr. Ostro created the field of asteroid radar astronomy, as well as mentoring and training the next group of scientists. Using the radar strength of radio telescopes such as the 305-meter telescope located at Arecibo Observatory in Puerto Rico and the telescopes at Goldstone Observatory in California, Dr. Ostro and his team produced fascinatingly detailed images of asteroids.
In applying radar techniques to asteroids, he not only revolutionized the capacity to study the position, shape, size, spin state and geological surfaces of these objects, but also greatly increased astronomers' ability to predict potential close encounters of asteroids with Earth, pushing predictions up to ten times further into the future. Dr. Ostro's work could also directly aid any potential manned missions to asteroids in future years, which could someday lead to the mining of these objects for natural resources.
Notable observations by Dr. Ostro include: 4179 Toutatis - a contact binary asteroid with an exceptionally unique rotation state; 1999 KW4 - one of the first binary near-Earth asteroids known; and 216 Kleopatra - the first asteroid confirmed to have a surface composition of nickel-iron. In addition to asteroid research, Dr. Ostro used the Cassini-Huygens RADAR instrument to observe the icy satellites of Jupiter and Saturn, while radar observations of the moons of Mars clarified knowledge of their orbits.
In 2003, the Division for Planetary Sciences of the American Astronomical Society awarded Dr. Ostro the prestigious Gerard P. Kuiper Prize for outstanding contributions to the field of planetary science. Each year, the 1, 200-member division honors one scientist "whose achievements have most advanced our understanding of the planetary system." In both 1991 and 2004, Dr. Ostro was awarded NASA Medals for Exceptional Scientific Achievement as a result of his scientific accomplishments as well as his excellent leadership. The asteroid 3169 Ostro, discovered June 4, 1981, is named to commemorate his work.
Dr. Ostro was known to have an unwavering thirst for knowledge and was an avid reader. He had a dedicated work ethic and always gave 100%, no matter what was the task at hand. Dr. Ostro is especially remembered for the way he articulated so deliberately and eloquently: he always captivated his audience, whether it was family, friends or colleagues. He led an active lifestyle and was a passionate practitioner of Tai Chi. Overall, he was a loving father and a devoted husband.
Dr. Ostro is survived by his wife, Jeanne; their three children, Marguerite, Brian and Julianna; his brother, Stu; cousins Shirley Kline Bennett, Florence E. Kline, and Judy Bari; an uncle, Justin Ostro; and an aunt, Renee Wexler.
Dr. Ostro was a New Jersey native who earned bachelor's degrees in liberal arts and ceramic science from Rutgers University; a master's degree in engineering physics from Cornell University; and a doctorate in planetary sciences from the Massachusetts Institute of Technology. Beginning in 1979 - after a personal invitation from Carl Sagan - Dr. Ostro served as an assistant professor at Cornell University. In 1984, he began creating his life's legacy through his work at NASA's Jet Propulsion Laboratory in Pasadena, California.
Essentially, Dr. Ostro created the field of asteroid radar astronomy, as well as mentoring and training the next group of scientists. Using the radar strength of radio telescopes such as the 305-meter telescope located at Arecibo Observatory in Puerto Rico and the telescopes at Goldstone Observatory in California, Dr. Ostro and his team produced fascinatingly detailed images of asteroids.
In applying radar techniques to asteroids, he not only revolutionized the capacity to study the position, shape, size, spin state and geological surfaces of these objects, but also greatly increased astronomers' ability to predict potential close encounters of asteroids with Earth, pushing predictions up to ten times further into the future. Dr. Ostro's work could also directly aid any potential manned missions to asteroids in future years, which could someday lead to the mining of these objects for natural resources.
Notable observations by Dr. Ostro include: 4179 Toutatis - a contact binary asteroid with an exceptionally unique rotation state; 1999 KW4 - one of the first binary near-Earth asteroids known; and 216 Kleopatra - the first asteroid confirmed to have a surface composition of nickel-iron. In addition to asteroid research, Dr. Ostro used the Cassini-Huygens RADAR instrument to observe the icy satellites of Jupiter and Saturn, while radar observations of the moons of Mars clarified knowledge of their orbits.
In 2003, the Division for Planetary Sciences of the American Astronomical Society awarded Dr. Ostro the prestigious Gerard P. Kuiper Prize for outstanding contributions to the field of planetary science. Each year, the 1, 200-member division honors one scientist "whose achievements have most advanced our understanding of the planetary system." In both 1991 and 2004, Dr. Ostro was awarded NASA Medals for Exceptional Scientific Achievement as a result of his scientific accomplishments as well as his excellent leadership. The asteroid 3169 Ostro, discovered June 4, 1981, is named to commemorate his work.
Dr. Ostro was known to have an unwavering thirst for knowledge and was an avid reader. He had a dedicated work ethic and always gave 100%, no matter what was the task at hand. Dr. Ostro is especially remembered for the way he articulated so deliberately and eloquently: he always captivated his audience, whether it was family, friends or colleagues. He led an active lifestyle and was a passionate practitioner of Tai Chi. Overall, he was a loving father and a devoted husband.
Dr. Ostro is survived by his wife, Jeanne; their three children, Marguerite, Brian and Julianna; his brother, Stu; cousins Shirley Kline Bennett, Florence E. Kline, and Judy Bari; an uncle, Justin Ostro; and an aunt, Renee Wexler.
News.Scotsman.com
Tue, 23 Dec 2008 21:53 UTC
Scottish scientists have uncovered clues about a catastrophic event
that radically altered the Earth's surface almost 500 million years
ago.
Microscopic particles found in rocks on a Highland beach contain tiny remnants of meteorites. Experts at the University of Aberdeen believe the finds within rocks along the shore near Durness, Sutherland, are evidence of a massive collision in the asteroid belt 470 million years ago between Mars and Jupiter which resulted in thousands of meteorites landing on Earth.
The force of the impacts across the planet may have caused earthquakes and tidal waves, leading to erosion around the margins of the continents.
The research confirms previous scientific speculation that the meteorite shower was so vast it affected locations across the world, including Scotland.
Around the same time life on Earth - then restricted to the ocean's and seas - flourished with thousands of new species.
Comment: So many speculations, yet no one considers the possibility that the sound might have been produced by falling meteorites. After all, the Ursid Meteor shower happens around this time of year.
Microscopic particles found in rocks on a Highland beach contain tiny remnants of meteorites. Experts at the University of Aberdeen believe the finds within rocks along the shore near Durness, Sutherland, are evidence of a massive collision in the asteroid belt 470 million years ago between Mars and Jupiter which resulted in thousands of meteorites landing on Earth.
The force of the impacts across the planet may have caused earthquakes and tidal waves, leading to erosion around the margins of the continents.
The research confirms previous scientific speculation that the meteorite shower was so vast it affected locations across the world, including Scotland.
Around the same time life on Earth - then restricted to the ocean's and seas - flourished with thousands of new species.
Nicholas Bergin
The Hawk Eye
Wed, 24 Dec 2008 17:28 UTC
Mysterious booms heard south of Burlington Saturday night have many residents scratching their heads.
Law enforcement dispatchers said residents in Wever, West Point, Fort Madison and Keokuk reported hearing a loud noise -- strong enough to shake a house -- between 6:30 and 7 p.m. followed by other lesser booms at varying times Saturday night.
Law enforcement officials have theories about what caused the sounds but no concrete answers.
"I have no clue (of the cause)," said Lee County Sheriff Buck Jones. "I don't know of anyone blasting around here."
Jones said he wrote the incident off as explosions at the Iowa Ammunition Army Plant. But no munitions are tested after dark by American Ordnance, which operates and maintains the plant.
"It wasn't us on a Saturday night," said Doug Hanify, deputy director of business development for American Ordinance. "We don't test at night time."
Another theory was that the sound was a sonic boom caused by a plane breaking the sound barrier, which is what Lee County Emergency Management Coordinator Stephen Cirinna believes.
"It rattled my house in Montrose. ... At first I thought a tree had fallen on my house," said Cirinna, who grew up hearing the sound barrier being broken as the child of an Air Force veteran. "I'm passing it off as a sonic boom at this point."
However, Federal Aviation Administration spokeswoman Elizabeth Isham Cory said records Saturday showed no military or domestic aircraft in the area.
"We looked up the radar. We had no planes in the area. So I don't know what it was. It wasn't an aircraft," Isham Cory said.
But Cirinna said it still could have been caused by some kind of military test, which officials may not be forthcoming about.
A similar sound several years ago turned out to be a test of a military plane based at the Scott Air Force Base, east of St. Louis, Cirinna said.
This would not be the first time a loud noise in the area has gone unexplained.
"We had the same thing about a year-and-a-half ago during the warmer weather. Nobody ever figured out what it was," Jones said.
Alliant Energy spokesman Scott Smith suggested the source of the sound likely was electrical fuses blowing as ice and high winds of up to 45 mph caused power lines to cross.
"It's just like an M-80 going off," he said.
The fuses are designed to blow to prevent surges from traveling through power lines to substations and causing widespread power outages.
However, those who heard the sounds expressed doubts about the explanation.
Loud sounds also were heard in Kirksville, Mo., about 90 miles southwest of Keokuk, said David Hall, director of the Kirksville Regional Airport.
Hall said he heard the noise several times at home and compared it to a cannon being fired or someone pounding on a deck with a sledge hammer.
"I guarantee you I heard it," Hall said. "At first I thought it was popping and cracking from the cold. The temperature was just plummeting that evening. But it was obviously more than that.
"Several people heard it. Our (Kirksville) 911 dispatch center called and asked me if I knew anything about it. I don't have any idea what it was."
Law enforcement dispatchers said residents in Wever, West Point, Fort Madison and Keokuk reported hearing a loud noise -- strong enough to shake a house -- between 6:30 and 7 p.m. followed by other lesser booms at varying times Saturday night.
Law enforcement officials have theories about what caused the sounds but no concrete answers.
"I have no clue (of the cause)," said Lee County Sheriff Buck Jones. "I don't know of anyone blasting around here."
Jones said he wrote the incident off as explosions at the Iowa Ammunition Army Plant. But no munitions are tested after dark by American Ordnance, which operates and maintains the plant.
"It wasn't us on a Saturday night," said Doug Hanify, deputy director of business development for American Ordinance. "We don't test at night time."
Another theory was that the sound was a sonic boom caused by a plane breaking the sound barrier, which is what Lee County Emergency Management Coordinator Stephen Cirinna believes.
"It rattled my house in Montrose. ... At first I thought a tree had fallen on my house," said Cirinna, who grew up hearing the sound barrier being broken as the child of an Air Force veteran. "I'm passing it off as a sonic boom at this point."
However, Federal Aviation Administration spokeswoman Elizabeth Isham Cory said records Saturday showed no military or domestic aircraft in the area.
"We looked up the radar. We had no planes in the area. So I don't know what it was. It wasn't an aircraft," Isham Cory said.
But Cirinna said it still could have been caused by some kind of military test, which officials may not be forthcoming about.
A similar sound several years ago turned out to be a test of a military plane based at the Scott Air Force Base, east of St. Louis, Cirinna said.
This would not be the first time a loud noise in the area has gone unexplained.
"We had the same thing about a year-and-a-half ago during the warmer weather. Nobody ever figured out what it was," Jones said.
Alliant Energy spokesman Scott Smith suggested the source of the sound likely was electrical fuses blowing as ice and high winds of up to 45 mph caused power lines to cross.
"It's just like an M-80 going off," he said.
The fuses are designed to blow to prevent surges from traveling through power lines to substations and causing widespread power outages.
However, those who heard the sounds expressed doubts about the explanation.
Loud sounds also were heard in Kirksville, Mo., about 90 miles southwest of Keokuk, said David Hall, director of the Kirksville Regional Airport.
Hall said he heard the noise several times at home and compared it to a cannon being fired or someone pounding on a deck with a sledge hammer.
"I guarantee you I heard it," Hall said. "At first I thought it was popping and cracking from the cold. The temperature was just plummeting that evening. But it was obviously more than that.
"Several people heard it. Our (Kirksville) 911 dispatch center called and asked me if I knew anything about it. I don't have any idea what it was."
Comment: So many speculations, yet no one considers the possibility that the sound might have been produced by falling meteorites. After all, the Ursid Meteor shower happens around this time of year.
Chris Anderson
Times News
Thu, 25 Dec 2008 21:35 UTC
In addition to celebrating Christmas today, science history buffs might
note that today is also the 250th anniversary of a notable return of
Halley's Comet in the skies over Germany.
Edmond Halley was a contemporary of Isaac Newton. In addition to his own manifold contributions to science, he convinced Newton to write his seminal book, "Mathematical Principles of Science," and even paid for its publishing.
In Halley's time comets were thought to be one-time phenomena. In 1705, after searching historical records and calculating orbits, Halley published his hypothesis that four comets seen in the previous 250 years were actually the same comet, on an orbit that brought it back to the inner solar system every 76 years. He predicted the comet's return in 1758, but died 16 years too early to see if he had been right.
Given Halley's reputation, astronomers worldwide began to scan the skies in 1758. But as the year wore on and the comet failed to appear, most lost interest and wrote off Halley's prediction as a failure. What they didn't know was that - unlike planets - comets' orbital periods can vary considerably. When a comet crosses a planets' orbit, the planet's gravity can perturb the comet's motion. Also, as comets approach the sun, frozen gases are boiled away, producing a jet effect. Consequently, Halley's Comet was running nearly two years behind schedule.
Finally, on the night of Christmas, 1758, German amateur astronomer Johann Palitzsch spotted the tardy comet. The comet was immediately named in Halley's honor, securing his place in history. (Astronomical historians have since found nearly a dozen other historical records of previous apparitions of Halley's Comet, the oldest being Chinese chronicles written in 240 B.C.)
Palitzsch's name barely rises to the level of historical trivia nowadays. But perhaps we should at least acknowledge his posthumous Christmas gift to Edmond Halley.
Astronomer Boattini spots seven in one year
Italian
astronomer Andrea Boattini broke the record for the number of new
comets sighted in one year when he spotted his seventh at Christmas.
The previous record had been held for some 150 years by Italian astronomers Francesco De Vito and Giovanni Battista Donati who in the mid-1800s sighted six comets in one year.
The new comet has the technical tag C/2008 Y1 but like the others has also been given its discoverer's name.
Boattini, 39, who works at the Mount Lemmon Observatory in Arizona, sighted the comet on December 22 during a search to spot comets and asteroids which could potentially pose a threat to the Earth.
''The latter half of this year has been very important for our group and resulted in NASA renewing its financing of our activities to the end of 2012,'' Boattini said.
NASA funds the Catalina Sky Survey at the University of Arizona dedicated to searching the skies for asteroids travelling near the earth.
The Italian astronomer also has 170 asteroid sightings under his belt and this year burnished his reputation further by finding the closest of those rocks to the Sun.
Boattini is an expert in comets and asteroids and specialises in Near Earth Objects (NEOs).
Edmond Halley was a contemporary of Isaac Newton. In addition to his own manifold contributions to science, he convinced Newton to write his seminal book, "Mathematical Principles of Science," and even paid for its publishing.
In Halley's time comets were thought to be one-time phenomena. In 1705, after searching historical records and calculating orbits, Halley published his hypothesis that four comets seen in the previous 250 years were actually the same comet, on an orbit that brought it back to the inner solar system every 76 years. He predicted the comet's return in 1758, but died 16 years too early to see if he had been right.
Given Halley's reputation, astronomers worldwide began to scan the skies in 1758. But as the year wore on and the comet failed to appear, most lost interest and wrote off Halley's prediction as a failure. What they didn't know was that - unlike planets - comets' orbital periods can vary considerably. When a comet crosses a planets' orbit, the planet's gravity can perturb the comet's motion. Also, as comets approach the sun, frozen gases are boiled away, producing a jet effect. Consequently, Halley's Comet was running nearly two years behind schedule.
Finally, on the night of Christmas, 1758, German amateur astronomer Johann Palitzsch spotted the tardy comet. The comet was immediately named in Halley's honor, securing his place in history. (Astronomical historians have since found nearly a dozen other historical records of previous apparitions of Halley's Comet, the oldest being Chinese chronicles written in 240 B.C.)
Palitzsch's name barely rises to the level of historical trivia nowadays. But perhaps we should at least acknowledge his posthumous Christmas gift to Edmond Halley.
Ansa.it
Mon, 29 Dec 2008 14:20 UTC
Astronomer Boattini spots seven in one year
The previous record had been held for some 150 years by Italian astronomers Francesco De Vito and Giovanni Battista Donati who in the mid-1800s sighted six comets in one year.
The new comet has the technical tag C/2008 Y1 but like the others has also been given its discoverer's name.
Boattini, 39, who works at the Mount Lemmon Observatory in Arizona, sighted the comet on December 22 during a search to spot comets and asteroids which could potentially pose a threat to the Earth.
''The latter half of this year has been very important for our group and resulted in NASA renewing its financing of our activities to the end of 2012,'' Boattini said.
NASA funds the Catalina Sky Survey at the University of Arizona dedicated to searching the skies for asteroids travelling near the earth.
The Italian astronomer also has 170 asteroid sightings under his belt and this year burnished his reputation further by finding the closest of those rocks to the Sun.
Boattini is an expert in comets and asteroids and specialises in Near Earth Objects (NEOs).
The Library of Congress
Mon, 29 Dec 2008 08:49 UTC
SEC. 321. GEORGE E. BROWN, JR. NEAR-EARTH OBJECT SURVEY.
(a) Short Title- This section may be cited as the 'George E. Brown, Jr. Near-Earth Object Survey Act'.
(b) Findings- The Congress makes the following findings:
(d) Near-Earth Object Survey-
(a) Short Title- This section may be cited as the 'George E. Brown, Jr. Near-Earth Object Survey Act'.
(b) Findings- The Congress makes the following findings:
(1) Near-Earth objects pose a serious and credible threat to humankind, as many scientists believe that a major asteroid or comet was responsible for the mass extinction of the majority of the Earth's species, including the dinosaurs, nearly 65,000,000 years ago.(c) Definitions- For purposes of this section the term 'near-Earth object' means an asteroid or comet with a perihelion distance of less than 1.3 Astronomical Units from the Sun.
(2) Similar objects have struck the Earth or passed through the Earth's atmosphere several times in the Earth's history and pose a similar threat in the future.
(3) Several such near-Earth objects have only been discovered within days of the objects' closest approach to Earth, and recent discoveries of such large objects indicate that many large near-Earth objects remain undiscovered.
(4) The efforts taken to date by NASA for detecting and characterizing the hazards of near-Earth objects are not sufficient to fully determine the threat posed by such objects to cause widespread destruction and loss of life.
(d) Near-Earth Object Survey-
(1) SURVEY PROGRAM- The Administrator shall plan, develop, and implement a Near-Earth Object Survey program to detect, track, catalogue, and characterize the physical characteristics of near-Earth objects equal to or greater than 140 meters in diameter in order to assess the threat of such near-Earth objects to the Earth. It shall be the goal of the Survey program to achieve 90 percent completion of its near-Earth object catalogue (based on statistically predicted populations of near-Earth objects) within 15 years after the date of enactment of this Act.
(2) AMENDMENTS- Section 102 of the National Aeronautics and Space Act of 1958 (42 U.S.C. 2451) is amended--(A) by redesignating subsection (g) as subsection (h);(3) FIFTH-YEAR REPORT- The Administrator shall transmit to the Congress, not later than February 28 of the fifth year after the date of enactment of this Act, a report that provides the following:
(B) by inserting after subsection (f) the following new subsection:
'(g) The Congress declares that the general welfare and security of the United States require that the unique competence of the National Aeronautics and Space Administration be directed to detecting, tracking, cataloguing, and characterizing near-Earth asteroids and comets in order to provide warning and mitigation of the potential hazard of such near-Earth objects to the Earth.'; and
(C) in subsection (h), as so redesignated by subparagraph (A) of this paragraph, by striking 'and (f)' and inserting '(f), and (g)'.(A) A summary of all activities taken pursuant to paragraph (1) since the date of enactment of this Act.(4) INITIAL REPORT- The Administrator shall transmit to Congress not later than 1 year after the date of enactment of this Act an initial report that provides the following:
(B) A summary of expenditures for all activities pursuant to paragraph (1) since the date of enactment of this Act.(A) An analysis of possible alternatives that NASA may employ to carry out the Survey program, including ground-based and space-based alternatives with technical descriptions.
(B) A recommended option and proposed budget to carry out the Survey program pursuant to the recommended option.
(C) Analysis of possible alternatives that NASA could employ to divert an object on a likely collision course with Earth.
Heather Olinger
News 2 NBC
Tue, 30 Dec 2008 16:15 UTC
All afternoon, our newsroom has been flooded with calls, emails and
twitter messages, about a loud boom heard in, and around, Mt. Pleasant.
We've gotten emails from Dunes West, Rivertowne Country club, Seaside farms, Hamlin Plantation, Brickyard, and even as far as Isle of Palms.
People who heard the sound described it as a loud explosion that started around 1:45pm, and only lasted for about 30 to 45 seconds. And many of you said your homes shook...
According the US Geological Survey, there have been no signs of an earthquake, officials at the Wando Port terminal say they haven't experienced anything out of the ordinary.
We went looking for answers and found it actually happens all over the place all the time.
Residents in Sarasota, Florida were shaken in March by a loud noise. The unofficial cause, a space shuttle re-entering the earth's atmosphere.
Last week, it happened in Iowa, folks there are still looking for an explanation. So are a lot of people in one illinois town.
Since military aircraft are known to break the sound barrier, we called the Air Force and the Navy.
Officials we spoke with knew of no training exercises taking place, but say it is a possibility.
The National Weather Service suggests a phenomenon known as Seneca Guns, a loud boom that happens in late fall and early winter in many ocean or lakefront communities.
We've gotten emails from Dunes West, Rivertowne Country club, Seaside farms, Hamlin Plantation, Brickyard, and even as far as Isle of Palms.
People who heard the sound described it as a loud explosion that started around 1:45pm, and only lasted for about 30 to 45 seconds. And many of you said your homes shook...
According the US Geological Survey, there have been no signs of an earthquake, officials at the Wando Port terminal say they haven't experienced anything out of the ordinary.
We went looking for answers and found it actually happens all over the place all the time.
Residents in Sarasota, Florida were shaken in March by a loud noise. The unofficial cause, a space shuttle re-entering the earth's atmosphere.
Last week, it happened in Iowa, folks there are still looking for an explanation. So are a lot of people in one illinois town.
Since military aircraft are known to break the sound barrier, we called the Air Force and the Navy.
Officials we spoke with knew of no training exercises taking place, but say it is a possibility.
The National Weather Service suggests a phenomenon known as Seneca Guns, a loud boom that happens in late fall and early winter in many ocean or lakefront communities.
Tue, 30 Dec 2008 21:20 UTC
WMUR Channel 9
According to the astronomy Web site spaceweather.com, witnesses saw the
meteor at about 9:30 p.m. in skies over New Hampshire, Maine and New
York.
The meteor cut across the sky for a few seconds before exploding. It was unclear whether any pieces reached the ground.
Witnesses said the meteor had an apparent magnitude of about -9. The brighter an object, the lower the magnitude. In comparison, the full moon has a magnitude of -12.6 and Venus can reach a magnitude of -4.7.
Did you see the fireball? Let us know by sending us an e-mail. Or, if you have a picture or video of the fireball, log on to u local to send it to us!
The meteor cut across the sky for a few seconds before exploding. It was unclear whether any pieces reached the ground.
Witnesses said the meteor had an apparent magnitude of about -9. The brighter an object, the lower the magnitude. In comparison, the full moon has a magnitude of -12.6 and Venus can reach a magnitude of -4.7.
Did you see the fireball? Let us know by sending us an e-mail. Or, if you have a picture or video of the fireball, log on to u local to send it to us!
New York Times
Tue, 30 Dec 2008 19:26 UTC
The tsunami washed over Fire Island and, to the west, waves perhaps as
high as 20 feet spilled into Lower Manhattan. The furious onrush of
water left sediment a foot and a half deep on the Jersey Shore, and
debris cascaded far up the Hudson River.
No, there's no need to rush to higher ground, commandeer a rowboat in Central Park or empty the closet to grab the rubber boots. This disaster occurred about 2,300 years ago, though how bad it was, or even if it was a tsunami, remains in dispute.
But several geologists have collected evidence indicating that something very big and unusual occurred in waters near the New York area around 300 B.C., give or take a century. And Dallas Abbott, a research scientist at Columbia University's Lamont-Doherty Earth Observatory, is asserting that a meteorite, landing somewhere in the Atlantic, generated the tsunami.
Someone at the tip of Lower Manhattan then would probably have seen "something coming in," Dr. Abbott said. "Then you would hear a big bang, maybe a series of bangs, something that sounded like gunfire or cannons. It would be a really, really loud noise. And then you would be knocked to the ground by the air blast. And then you would be inundated by the tsunami."
While not nearly as severe as the tsunami that killed more than 180,000 people in South and Southeast Asia in 2004, "it would have been a bad day to end all bad days," she said, "in all senses."
Although American Indians had long been living in and around the area that became New York, Dr. Abbott said there was no archeological evidence of a tsunami or known legends of, say, a terrible flood. She has built her case with diamonds, very tiny ones.
At a meeting of the American Geophysical Union in San Francisco earlier this month, Dr. Abbott reported finding minute carbon spheres and smaller-than-dust diamonds in sediment layers, which she said were the distinctive calling cards of a meteorite's impact.
"I think it's pretty convincing," Dr. Abbott said. "We always find the impact ejecta in the tsunami layer, never outside."
A few years ago, the geologist Steven Goodbred, then at the State University of New York at Stony Brook, was not looking for tsunamis or meteorites when he first examined sediment cores taken along the South Shore of Long Island. Dr. Goodbred was interested in the history of oysters in that area. But in the very first core, he saw a strange layer several inches thick containing fist-size gravel.
"We started joking immediately, 'It's a tsunami,' " recalled Dr. Goodbred, now a professor at Vanderbilt University in Nashville.
Subsequent cores, taken in Great South Bay, also contained that layer, deposited about 2,300 years ago. When Dr. Goodbred presented his findings at a conference a couple of years ago, he failed to convince other scientists. They said the layer was more likely caused by a big storm, not a tsunami.
"Even if it was a storm, it was the mother of all storms," Dr. Goodbred said, pointing out that the devastating hurricane that passed directly over Long Island in 1938 generated less than an inch of sediment.
Then Dr. Goodbred met other scientists who had found similar sediment layers nearby. Cecilia McHugh, a professor at Queens College, had seen a sediment layer a foot and a half thick at Sandy Hook in New Jersey. That, too, was laid down about 2,300 years ago. And Frank Nitsche, another research scientist at Lamont-Doherty, had discovered a layer of wood debris in sediment cores from the upstate reaches of the Hudson River.
Then Dr. Abbott joined the project and found possible evidence of a meteorite.
But the arguments of a meteor causing a New York tsunami are still regarded skeptically by many, if not most, geologists. For one, no one has found any craters.
The evidence hinges most strongly on the tiny diamonds, presumably formed by the ultra-high pressures of impact.
The carbon atoms inside some of the diamonds are lined up in a hexagonal crystal structure instead of the usual cubic crystals. The hexagonal diamonds have been found only within meteorites and at impact craters, said Allen West, a geologist who performed the diamond analysis for Dr. Abbott's New York sediments.
But unless researchers find a crater in the ocean floor, an Indian legend telling of a day of fire and water or many more thick sediment deposits, convincing other scientists of what they believe happened 2,300 years ago will continue to be an uphill battle.
No, there's no need to rush to higher ground, commandeer a rowboat in Central Park or empty the closet to grab the rubber boots. This disaster occurred about 2,300 years ago, though how bad it was, or even if it was a tsunami, remains in dispute.
But several geologists have collected evidence indicating that something very big and unusual occurred in waters near the New York area around 300 B.C., give or take a century. And Dallas Abbott, a research scientist at Columbia University's Lamont-Doherty Earth Observatory, is asserting that a meteorite, landing somewhere in the Atlantic, generated the tsunami.
Someone at the tip of Lower Manhattan then would probably have seen "something coming in," Dr. Abbott said. "Then you would hear a big bang, maybe a series of bangs, something that sounded like gunfire or cannons. It would be a really, really loud noise. And then you would be knocked to the ground by the air blast. And then you would be inundated by the tsunami."
While not nearly as severe as the tsunami that killed more than 180,000 people in South and Southeast Asia in 2004, "it would have been a bad day to end all bad days," she said, "in all senses."
Although American Indians had long been living in and around the area that became New York, Dr. Abbott said there was no archeological evidence of a tsunami or known legends of, say, a terrible flood. She has built her case with diamonds, very tiny ones.
© Dee Breger/Drexel University
A Columbia scientist has reported finding carbon spheres, above, in sediment, indicating a meteorite.
A Columbia scientist has reported finding carbon spheres, above, in sediment, indicating a meteorite.
At a meeting of the American Geophysical Union in San Francisco earlier this month, Dr. Abbott reported finding minute carbon spheres and smaller-than-dust diamonds in sediment layers, which she said were the distinctive calling cards of a meteorite's impact.
"I think it's pretty convincing," Dr. Abbott said. "We always find the impact ejecta in the tsunami layer, never outside."
A few years ago, the geologist Steven Goodbred, then at the State University of New York at Stony Brook, was not looking for tsunamis or meteorites when he first examined sediment cores taken along the South Shore of Long Island. Dr. Goodbred was interested in the history of oysters in that area. But in the very first core, he saw a strange layer several inches thick containing fist-size gravel.
"We started joking immediately, 'It's a tsunami,' " recalled Dr. Goodbred, now a professor at Vanderbilt University in Nashville.
Subsequent cores, taken in Great South Bay, also contained that layer, deposited about 2,300 years ago. When Dr. Goodbred presented his findings at a conference a couple of years ago, he failed to convince other scientists. They said the layer was more likely caused by a big storm, not a tsunami.
"Even if it was a storm, it was the mother of all storms," Dr. Goodbred said, pointing out that the devastating hurricane that passed directly over Long Island in 1938 generated less than an inch of sediment.
Then Dr. Goodbred met other scientists who had found similar sediment layers nearby. Cecilia McHugh, a professor at Queens College, had seen a sediment layer a foot and a half thick at Sandy Hook in New Jersey. That, too, was laid down about 2,300 years ago. And Frank Nitsche, another research scientist at Lamont-Doherty, had discovered a layer of wood debris in sediment cores from the upstate reaches of the Hudson River.
Then Dr. Abbott joined the project and found possible evidence of a meteorite.
But the arguments of a meteor causing a New York tsunami are still regarded skeptically by many, if not most, geologists. For one, no one has found any craters.
The evidence hinges most strongly on the tiny diamonds, presumably formed by the ultra-high pressures of impact.
The carbon atoms inside some of the diamonds are lined up in a hexagonal crystal structure instead of the usual cubic crystals. The hexagonal diamonds have been found only within meteorites and at impact craters, said Allen West, a geologist who performed the diamond analysis for Dr. Abbott's New York sediments.
But unless researchers find a crater in the ocean floor, an Indian legend telling of a day of fire and water or many more thick sediment deposits, convincing other scientists of what they believe happened 2,300 years ago will continue to be an uphill battle.
Scott Jason
Merced Sun-Star
Tue, 30 Dec 2008 21:28 UTC
A glowing tomato-green fireball shot through the black Merced sky early
Saturday, stunning those fortunate enough to see its brief life.
Merced resident Erika Knorn, 42, had awoken just before 2 a.m. to take her dog, Shadow, to the bathroom before returning to bed.
She gazed toward the sky and noticed the burst of color above her house near East Olive and Parsons avenues.
Erika Knorn describes witnessing a spectacular "fireball" in the sky above Merced early Saturday morning.
"Oh my gosh! Oh my gosh! What is that?" she recalled saying that night as if someone would answer. "Oh my gosh!"
Was it a flare? she wondered. Was it a missile?
The flash, which resembled a bright white beach ball, moved in a northwesterly descent for about six seconds, she said.
Then it turned blue-green. Three waves of light pulsed through the sky. It then began releasing gold and white sparks. About a minute later she heard three sharp booms that startled her dog into barking a few times. Other dogs in the neighborhood began howling.
She hasn't been able to get the image of it out of her head. "It was beautiful and scary in a way," she explained Monday. "I don't think I want to see one that close again."
Knorn was pointed to www.spaceweather.com, which allows people to post stories about fireball sightings.
There she found a few other accounts from people in Bishop in Inyo County, Corona in Riverside County and San Jose.
Grant Bentley wrote, "It was as if someone had set off a rescue flare that instantly bathed the countryside around Bishop in whitish blue-green light. It was easily the most massive object I have ever seen burning up as it entered the Earth's atmosphere."
George Shirakawa was driving on Interstate 280 in San Jose at the time. He wrote, "I have never seen anything like it!"
Arizona-based meteorite hunter Robert Ward said the noise Knorn heard was meteor crashing into land, thereby becoming a meteorite.
Ward, 32, has gone on more than 30 successful meteorite expeditions in the Middle East, Europe, Africa and North America. He sells and trades some of the pieces he finds. Prices average at about $1 a gram, but can get as expensive as $1,000 a gram if the meteorite is from Mars or the moon. (A little more than 28 grams make an ounce.)
Based on the descriptions he's read, Ward said Knorn and others probably saw a fireball, which is a brighter version of a meteor. Meteorites can be the size of microwave ovens and even refrigerators, he said. They travel between 11,000 and 30,000 miles an hour.
The noise she heard means the meteorite may have gone to ground near or even in Merced County, he said. He's found space rocks 50 miles from people who've heard sonic booms.
Ward is contacting people in the state who have sky cameras to see if he can re-create the meteor's path and begin a recovery effort. "If I got the right information, I'd leave immediately," he said.
The most common type of meteorite is a chondrite, which is mostly silicate but contains traces of nickel and iron.
After seeing the fireball, Knorn stayed in her backyard and scanned the sky to see if any others would fall.
"I am going to start (meteor watching). It made me go, 'Wow, life,'" she said. "It changed my way of looking up."
Reporter Scott Jason can be reached at (209) 385-2453 or sjason@mercedsun-star.com.
Merced resident Erika Knorn, 42, had awoken just before 2 a.m. to take her dog, Shadow, to the bathroom before returning to bed.
She gazed toward the sky and noticed the burst of color above her house near East Olive and Parsons avenues.
Erika Knorn describes witnessing a spectacular "fireball" in the sky above Merced early Saturday morning.
"Oh my gosh! Oh my gosh! What is that?" she recalled saying that night as if someone would answer. "Oh my gosh!"
Was it a flare? she wondered. Was it a missile?
The flash, which resembled a bright white beach ball, moved in a northwesterly descent for about six seconds, she said.
Then it turned blue-green. Three waves of light pulsed through the sky. It then began releasing gold and white sparks. About a minute later she heard three sharp booms that startled her dog into barking a few times. Other dogs in the neighborhood began howling.
She hasn't been able to get the image of it out of her head. "It was beautiful and scary in a way," she explained Monday. "I don't think I want to see one that close again."
Knorn was pointed to www.spaceweather.com, which allows people to post stories about fireball sightings.
There she found a few other accounts from people in Bishop in Inyo County, Corona in Riverside County and San Jose.
Grant Bentley wrote, "It was as if someone had set off a rescue flare that instantly bathed the countryside around Bishop in whitish blue-green light. It was easily the most massive object I have ever seen burning up as it entered the Earth's atmosphere."
George Shirakawa was driving on Interstate 280 in San Jose at the time. He wrote, "I have never seen anything like it!"
Arizona-based meteorite hunter Robert Ward said the noise Knorn heard was meteor crashing into land, thereby becoming a meteorite.
Ward, 32, has gone on more than 30 successful meteorite expeditions in the Middle East, Europe, Africa and North America. He sells and trades some of the pieces he finds. Prices average at about $1 a gram, but can get as expensive as $1,000 a gram if the meteorite is from Mars or the moon. (A little more than 28 grams make an ounce.)
Based on the descriptions he's read, Ward said Knorn and others probably saw a fireball, which is a brighter version of a meteor. Meteorites can be the size of microwave ovens and even refrigerators, he said. They travel between 11,000 and 30,000 miles an hour.
The noise she heard means the meteorite may have gone to ground near or even in Merced County, he said. He's found space rocks 50 miles from people who've heard sonic booms.
Ward is contacting people in the state who have sky cameras to see if he can re-create the meteor's path and begin a recovery effort. "If I got the right information, I'd leave immediately," he said.
The most common type of meteorite is a chondrite, which is mostly silicate but contains traces of nickel and iron.
After seeing the fireball, Knorn stayed in her backyard and scanned the sky to see if any others would fall.
"I am going to start (meteor watching). It made me go, 'Wow, life,'" she said. "It changed my way of looking up."
Reporter Scott Jason can be reached at (209) 385-2453 or sjason@mercedsun-star.com.
Liza Roberts
Raleigh Metro Magazine
Tue, 30 Dec 2008 19:36 UTC
George Howard is many things. He is the president of the Raleigh-based
Restoration Systems mitigation bank and a conservationist; he is a
history buff, a science geek, a cartographer. The 42-year-old family
man is a talented amateur artist, a dedicated if unprolific fisherman
and a politico whose office photos show him chummy with folks including
Jesse Helms, Newt Gingrich, Lauch Faircloth and both George Bushes.
But what really gets Howard going - gets him talking a mile a minute, playing hooky from work and waking up at night - is his research into a geographical oddity known as the Carolina Bays.
These elliptical, wetland depressions, often rimmed with white, crystalline sand, are sprinkled along much of the North Carolina coast and parts of the eastern seaboard from Georgia to the District of Columbia. To Howard and those who share both his interest and his theory, these droplet-shaped dents (often choked with bay trees, hence the name) were most likely caused by a life-obliterating comet that landed on earth about 13,000 years ago: in geologic terms, quite recently. Howard wants to prove this, and he wants the world to take note.
He also knows how his theory can sound: nuts. (His word.) But it's not, and he's not. In fact, the theory has some impressive bona fides: The National Academy of Sciences published a paper he a nd a small group of fellow researchers wrote on their findings. National Geographic has produced a documentary on the subject, and Howard and his research team were recently asked to speak on the subject at the prestigious American Geophysical Union's fall meeting.
But he also knows that real believing requires seeing. His favorite quotation, borrowed from the state motto of North Carolina, is "Esse Quam Videri," - "to be rather than to seem." He wants to show the evidence to prove his case. And so he is delighted for the chance to show an interested party just what he's talking about: these Carolina Bays, from above.
The Grand Tour
"You ready for the Grand Carolina Bays Tour?" Howard grins as the journey begins. The drive from downtown Raleigh to Fayetteville Regional Airport takes about an hour and a half - not nearly enough time for Howard to begin to say all he wants to say about what we're about to see. His primer begins with a basic refresher course on the evolution of the planet, veers into mythology, geology, ancient cultures, climate science, dinosaurs, botany; sidesteps frequently into humor and pop culture - and ends up deadly serious.
Howard would be aghast at the idea that it could be summed up, but here goes: 13,000 years ago, he says, a "cataclysmic event" happened when a comet hit the earth somewhere in the vicinity of the Great Lakes. It hit an ice sheet, acting like a big kid's cannon ball in the shallow end of a pool, throwing off a vast airborne splatter of "flying detritus," including extra-terrestrial particles that landed as far away as North Carolina. It's also possible that it created a shockwave that rippled across the landscape, dimpling it in the process, or that a little bit of both happened. Howard says it is certain that the comet decimated everything in its path, including the mammoths and the Clovis people, a well-documented Paleo-Indian civilization.
It Can Happen Here
Believing that such a thing happened as recently as 13,000 years ago implies that it could happen again, and possibly soon: not something most people are prepared to contemplate. But it's clear that for Howard, zipping down Interstate 95 and half-listening to CNBC's market-meltdown report on the radio, this possibility is neither abstract nor unimaginable. He waves his hand out the window, vaguely northward. "You wonder what came flying from that direction and landed here in these fields. Or what hell storm swept through and left these depressions."
Howard's fascination with that hell storm, these depressions and what it means for the future of our planet began years ago as a staffer for Lauch Faircloth in the US Senate. Studying a US Geological Survey map of Faircloth's farm, he noticed something unusual. "What are all those elliptical dotted lines on your farm, Senator?" he asked. Faircloth's casual reply: "Oh, you know, meteor holes."
Howard's "natural ferocious curiosity" took over, and he quickly became an expert on the subject. These "meteor holes," mostly too shallow to notice at ground-level, are clearly evident from above. First observed in the 1930s when the agricultural programs of the New Deal mandated county-by-county aerial photographs, they caused a sensation at the time. The number (more than 500,000 is the estimate), the symmetry, the fact that they all point in the same direction (toward Lake Michigan) - all gripped the public imagination, culminating in a 1933 piece in Harper's Monthly entitled "The Comet That Hit the Carolinas," by Edna Muldrow. But the scientific establishment ultimately pooh-poohed the comet theory, arguing that the bays were caused by wind, water and erosion over time, and the subject fell off the public radar.
If Howard has his way, that will change.
The Bays from Above
When we arrive at the airport, the fall weather is unseasonably warm. The skies are bright and clear, with a slight breeze, like a day in May. Our chartered plane is miniscule. It's so small we have to climb over its balsa-thin wings to pop into our seats through a Plexiglas-bubble hatch-top. We barely fit inside. Takeoff feels like racing down an empty street in a Matchbox car, until the thing lifts off - then it's just like floating.
We meander above the airport before crossing over I-95 and heading south into "Bays Territory." At first, nothing jumps out. And then it does. Two blurred, white-sand-edged ellipses, about 100-yards long and 30-yards wide, chase each other across a field of soy. Another one nearby forms a visible swamp. A ghostly pair of ovals lurk in a cleared field. Once you know what to look for, they're impossible to miss.
"They're everywhere," Howard says gleefully, snapping away with a long lens camera. The jigsaw of green fields, punctuated here and there by these graceful, sandy shapes, is a beautiful sight, but as we head over the border into South Carolina, Howard points out a less lovely landmark: "Make sure not to miss the big purple lagoons of pig piss!" He's not kidding. Countless pig farms pepper the horizon, their low-slung, silver-roofed pig houses each accompanied by a large, strangely purple, chemically treated lagoon of waste.
But as our flight path takes us over the Cape Fear River, the Bays are once again quite noticeable. They've multiplied, lying side-by-side now, then in rows, then in clusters. The chalk-white sand that surrounds many of them stands them out in stark relief; others are made distinct by the darker color of vegetation within their borders.
Bays are fertile ground, Howard points out. Blueberries in particular grow well in them. So do carnivorous plants: Venus flytraps, pitcher plants, sundews. "The highest concentration of Venus flytraps in the United States are found in Eastern North Carolina," he says. (According to the International Carnivorous Plant Society, this is in fact the case.) Is he implying that these plants literally ... came from Venus? "Well," he demurs, "that's far into the realm of speculation."
But Howard does not consider it speculation to point out the other extra-terrestrial evidence he says are harbored in the Bays: tiny magnetic spheres, iridium-laced grains and nanodiamonds. The chemical composition of these materials, as the science press has noted, is most similar to lunar rocks and meteorites. Howard describes nanodiamonds as a veritable diamond dust that lines the bottoms of the Bays - too minute to have any value except as proof of great carbon impact. He regularly sends Ziploc bags full of the stuff to Arizona geophysicist Allen West and to a lab at UC Berkeley for testing. In the past four years Howard estimates he's sent off more than a ton of sand from the Bays.
Looking Skyward
But despite his efforts and those of his fellow researchers, including scientists from the University of South Carolina, UC Berkeley, Brown University and UCLA, among others, the endorsement of the broader scientific community remains elusive. "It's hard for people who are steeped in their own paradigm to accept a radically different way of viewing the past," he says. He also points to a lack of understanding, knowledge and communication between different areas of the science establishment. As Howard puts it, "the astronomers won't look down and the geologists won't look up."
If Howard's efforts bear fruit, we'll all start taking a cautious look skyward, and not a moment too soon. "There should be more attention paid to planetary protection," he says. "We're way behind the curve on that. The number of people working on it could staff a McDonald's." NASA does provide the global majority of research funding into near-earth-object detection and disaster prevention, but Howard's not alone in fearing it's not nearly enough.
"I am a catastrophist," Howard concedes. "I think that things have happened in the past that were horrible and were recorded for us. We don't recognize the tune, but it's all there in myth and fable." And, he is certain: It's also recorded in the elliptical, wetland pocks that speckle our coastline; it's recorded in the magnetic, extra-terrestrial matter he says is embedded in the Mammoth tusk that hangs over his television; it's recorded in the diamond dust he FedExes across the country. The evidence is all there, he says, you just have to know how to look for it.
Indeed, Howard's wife kids him that he sees Carolina Bays everywhere he looks, even in the shapes of the raindrops on the windshield of his car. He smiles at the thought, forcing himself to end the day-long tutorial as his Grand Carolina Bays Tour draws to a close. "You ain't even heard half of it," he says, and he's not kidding.
For
meteor observers, the presence of an almost-full Moon cast a bright
pall on this month's performance of the Geminid Meteor Shower, normally
one of the best meteor displays of the year. But for a wild card,
another very good meteor shower may be right around corner. And for
this one, the Moon will not play a factor at all.
So, get out your 2009 calendar and put a big circle around Saturday morning, Jan. 3.
That's the expected peak date for the Quadrantids, a notoriously unpredictable meteor display. In 2009, peak activity is due to occur in the pre-dawn hours of Jan. 3 and will strongly favor western North America. If the "Quads" reach their full potential, observers blessed with clear, dark skies could be averaging one or two meteor sightings per minute in the hour or two prior to the break of dawn.
The Quadrantid (pronounced KWA-dran-tid) meteors provides one of the most intense annual meteor displays, with a brief, sharp maximum lasting but a few hours. Adolphe Quetelet of Brussels Observatory discovered the shower in the 1830's, and shortly afterward it was noted by several other astronomers in Europe and America.
The meteors are named after the obsolete constellation Quadrans Muralis the Mural or Wall Quadrant (an astronomical instrument), depicted in some 19th-century star atlases roughly midway between the end of the handle of the Big Dipper and the quadrilateral of stars marking the head of the constellation Draco. (The International Astronomical Union phased out Quadrans Muralis in 1922.)
Usually difficult to see
Unfortunately, many factors combine to make the peak of this display difficult to observe on a regular basis.
Peak intensity is exceedingly sharp: meteor rates exceed one-half of their highest value for only about 8 hours (compared to two days for the August Perseids). This means that the stream of particles that produce this shower is a narrow one - apparently derived within the last 500-years from a small comet. The parentage of the Quadrantids had long been a mystery. Then Dr. Peter Jenniskens, an astronomer at the SETI Institute in Mountain View, Calif., noticed that the orbit of 2003 EH1 - a small asteroid discovered in March 2003 - ''falls snug in the shower.'' He believes that this 1.2 mi. (2 km.) chunk of rock is the source of the Quadrantids; possibly this asteroid is the burnt out core of the lost comet C/1490 Y1.
As viewed from mid-northern latitudes, we have to get up before dawn to see the Quadrantids at their best. This is because the radiant - that part of the sky from where the meteors to emanate - is down low on the northern horizon until about midnight, rising slowly higher as the night progresses. The growing light of dawn ends meteor observing usually by around 7 a.m. So, if the "Quads" are to be seen at all, some part of that 8-hour active period must fall between 2 and 7 a.m.
In one out of every three years, bright moonlight spoils the view. Over northern latitudes, early January often sees inclement/unsettled weather. It is not surprising then, that the Quadrantids are not as well-observed as some of the other annual meteor showers, but 2009 could be an exception.
Excellent prospects in 2009
According to the International Meteor Organization, maximum activity this year is expected on 4:50 a.m. Pacific Standard Time on Jan. 3. For those across the western half of the United States and Canada, the radiant will soar high in the eastern sky just prior to the onset of morning twilight. Over the eastern United States and Canada, the spike of activity is predicted to come after sunrise.
Quadrantid meteors are described as bright and bluish with long silvery trains. Some years produce a mere handful, but for favorably placed observers, an excellent meteor display may be in the offing; at greatest activity, Quadrantid rates will likely range from 30 to 60 per hour for eastern parts of the U.S. and Canada, to perhaps 60 to 120 per hour for the western United States and Canada. For those in Europe, the shower's sharp peak will likely come long after sunrise. Nonetheless, hourly rates of perhaps 15 to 30 may still be seen.
As far as the moon is concerned, it will not be a factor at all this year. It's a waxing crescent, two days from first quarter phase and will have set around 11 p.m. local time on Friday, Jan. 2, leaving the rest of the night dark for meteor watching.
Meteor Watching 101: Tips and terms
Meteors and Meteor Showers: The Science
Online Sky Maps and More
But what really gets Howard going - gets him talking a mile a minute, playing hooky from work and waking up at night - is his research into a geographical oddity known as the Carolina Bays.
These elliptical, wetland depressions, often rimmed with white, crystalline sand, are sprinkled along much of the North Carolina coast and parts of the eastern seaboard from Georgia to the District of Columbia. To Howard and those who share both his interest and his theory, these droplet-shaped dents (often choked with bay trees, hence the name) were most likely caused by a life-obliterating comet that landed on earth about 13,000 years ago: in geologic terms, quite recently. Howard wants to prove this, and he wants the world to take note.
He also knows how his theory can sound: nuts. (His word.) But it's not, and he's not. In fact, the theory has some impressive bona fides: The National Academy of Sciences published a paper he a nd a small group of fellow researchers wrote on their findings. National Geographic has produced a documentary on the subject, and Howard and his research team were recently asked to speak on the subject at the prestigious American Geophysical Union's fall meeting.
But he also knows that real believing requires seeing. His favorite quotation, borrowed from the state motto of North Carolina, is "Esse Quam Videri," - "to be rather than to seem." He wants to show the evidence to prove his case. And so he is delighted for the chance to show an interested party just what he's talking about: these Carolina Bays, from above.
The Grand Tour
"You ready for the Grand Carolina Bays Tour?" Howard grins as the journey begins. The drive from downtown Raleigh to Fayetteville Regional Airport takes about an hour and a half - not nearly enough time for Howard to begin to say all he wants to say about what we're about to see. His primer begins with a basic refresher course on the evolution of the planet, veers into mythology, geology, ancient cultures, climate science, dinosaurs, botany; sidesteps frequently into humor and pop culture - and ends up deadly serious.
Howard would be aghast at the idea that it could be summed up, but here goes: 13,000 years ago, he says, a "cataclysmic event" happened when a comet hit the earth somewhere in the vicinity of the Great Lakes. It hit an ice sheet, acting like a big kid's cannon ball in the shallow end of a pool, throwing off a vast airborne splatter of "flying detritus," including extra-terrestrial particles that landed as far away as North Carolina. It's also possible that it created a shockwave that rippled across the landscape, dimpling it in the process, or that a little bit of both happened. Howard says it is certain that the comet decimated everything in its path, including the mammoths and the Clovis people, a well-documented Paleo-Indian civilization.
It Can Happen Here
Believing that such a thing happened as recently as 13,000 years ago implies that it could happen again, and possibly soon: not something most people are prepared to contemplate. But it's clear that for Howard, zipping down Interstate 95 and half-listening to CNBC's market-meltdown report on the radio, this possibility is neither abstract nor unimaginable. He waves his hand out the window, vaguely northward. "You wonder what came flying from that direction and landed here in these fields. Or what hell storm swept through and left these depressions."
Howard's fascination with that hell storm, these depressions and what it means for the future of our planet began years ago as a staffer for Lauch Faircloth in the US Senate. Studying a US Geological Survey map of Faircloth's farm, he noticed something unusual. "What are all those elliptical dotted lines on your farm, Senator?" he asked. Faircloth's casual reply: "Oh, you know, meteor holes."
Howard's "natural ferocious curiosity" took over, and he quickly became an expert on the subject. These "meteor holes," mostly too shallow to notice at ground-level, are clearly evident from above. First observed in the 1930s when the agricultural programs of the New Deal mandated county-by-county aerial photographs, they caused a sensation at the time. The number (more than 500,000 is the estimate), the symmetry, the fact that they all point in the same direction (toward Lake Michigan) - all gripped the public imagination, culminating in a 1933 piece in Harper's Monthly entitled "The Comet That Hit the Carolinas," by Edna Muldrow. But the scientific establishment ultimately pooh-poohed the comet theory, arguing that the bays were caused by wind, water and erosion over time, and the subject fell off the public radar.
If Howard has his way, that will change.
The Bays from Above
When we arrive at the airport, the fall weather is unseasonably warm. The skies are bright and clear, with a slight breeze, like a day in May. Our chartered plane is miniscule. It's so small we have to climb over its balsa-thin wings to pop into our seats through a Plexiglas-bubble hatch-top. We barely fit inside. Takeoff feels like racing down an empty street in a Matchbox car, until the thing lifts off - then it's just like floating.
We meander above the airport before crossing over I-95 and heading south into "Bays Territory." At first, nothing jumps out. And then it does. Two blurred, white-sand-edged ellipses, about 100-yards long and 30-yards wide, chase each other across a field of soy. Another one nearby forms a visible swamp. A ghostly pair of ovals lurk in a cleared field. Once you know what to look for, they're impossible to miss.
"They're everywhere," Howard says gleefully, snapping away with a long lens camera. The jigsaw of green fields, punctuated here and there by these graceful, sandy shapes, is a beautiful sight, but as we head over the border into South Carolina, Howard points out a less lovely landmark: "Make sure not to miss the big purple lagoons of pig piss!" He's not kidding. Countless pig farms pepper the horizon, their low-slung, silver-roofed pig houses each accompanied by a large, strangely purple, chemically treated lagoon of waste.
But as our flight path takes us over the Cape Fear River, the Bays are once again quite noticeable. They've multiplied, lying side-by-side now, then in rows, then in clusters. The chalk-white sand that surrounds many of them stands them out in stark relief; others are made distinct by the darker color of vegetation within their borders.
Bays are fertile ground, Howard points out. Blueberries in particular grow well in them. So do carnivorous plants: Venus flytraps, pitcher plants, sundews. "The highest concentration of Venus flytraps in the United States are found in Eastern North Carolina," he says. (According to the International Carnivorous Plant Society, this is in fact the case.) Is he implying that these plants literally ... came from Venus? "Well," he demurs, "that's far into the realm of speculation."
But Howard does not consider it speculation to point out the other extra-terrestrial evidence he says are harbored in the Bays: tiny magnetic spheres, iridium-laced grains and nanodiamonds. The chemical composition of these materials, as the science press has noted, is most similar to lunar rocks and meteorites. Howard describes nanodiamonds as a veritable diamond dust that lines the bottoms of the Bays - too minute to have any value except as proof of great carbon impact. He regularly sends Ziploc bags full of the stuff to Arizona geophysicist Allen West and to a lab at UC Berkeley for testing. In the past four years Howard estimates he's sent off more than a ton of sand from the Bays.
Looking Skyward
But despite his efforts and those of his fellow researchers, including scientists from the University of South Carolina, UC Berkeley, Brown University and UCLA, among others, the endorsement of the broader scientific community remains elusive. "It's hard for people who are steeped in their own paradigm to accept a radically different way of viewing the past," he says. He also points to a lack of understanding, knowledge and communication between different areas of the science establishment. As Howard puts it, "the astronomers won't look down and the geologists won't look up."
If Howard's efforts bear fruit, we'll all start taking a cautious look skyward, and not a moment too soon. "There should be more attention paid to planetary protection," he says. "We're way behind the curve on that. The number of people working on it could staff a McDonald's." NASA does provide the global majority of research funding into near-earth-object detection and disaster prevention, but Howard's not alone in fearing it's not nearly enough.
"I am a catastrophist," Howard concedes. "I think that things have happened in the past that were horrible and were recorded for us. We don't recognize the tune, but it's all there in myth and fable." And, he is certain: It's also recorded in the elliptical, wetland pocks that speckle our coastline; it's recorded in the magnetic, extra-terrestrial matter he says is embedded in the Mammoth tusk that hangs over his television; it's recorded in the diamond dust he FedExes across the country. The evidence is all there, he says, you just have to know how to look for it.
Indeed, Howard's wife kids him that he sees Carolina Bays everywhere he looks, even in the shapes of the raindrops on the windshield of his car. He smiles at the thought, forcing himself to end the day-long tutorial as his Grand Carolina Bays Tour draws to a close. "You ain't even heard half of it," he says, and he's not kidding.
Joe Rao
Live Science
Wed, 31 Dec 2008 20:31 UTC
© Unknown
So, get out your 2009 calendar and put a big circle around Saturday morning, Jan. 3.
That's the expected peak date for the Quadrantids, a notoriously unpredictable meteor display. In 2009, peak activity is due to occur in the pre-dawn hours of Jan. 3 and will strongly favor western North America. If the "Quads" reach their full potential, observers blessed with clear, dark skies could be averaging one or two meteor sightings per minute in the hour or two prior to the break of dawn.
The Quadrantid (pronounced KWA-dran-tid) meteors provides one of the most intense annual meteor displays, with a brief, sharp maximum lasting but a few hours. Adolphe Quetelet of Brussels Observatory discovered the shower in the 1830's, and shortly afterward it was noted by several other astronomers in Europe and America.
The meteors are named after the obsolete constellation Quadrans Muralis the Mural or Wall Quadrant (an astronomical instrument), depicted in some 19th-century star atlases roughly midway between the end of the handle of the Big Dipper and the quadrilateral of stars marking the head of the constellation Draco. (The International Astronomical Union phased out Quadrans Muralis in 1922.)
Usually difficult to see
Unfortunately, many factors combine to make the peak of this display difficult to observe on a regular basis.
Peak intensity is exceedingly sharp: meteor rates exceed one-half of their highest value for only about 8 hours (compared to two days for the August Perseids). This means that the stream of particles that produce this shower is a narrow one - apparently derived within the last 500-years from a small comet. The parentage of the Quadrantids had long been a mystery. Then Dr. Peter Jenniskens, an astronomer at the SETI Institute in Mountain View, Calif., noticed that the orbit of 2003 EH1 - a small asteroid discovered in March 2003 - ''falls snug in the shower.'' He believes that this 1.2 mi. (2 km.) chunk of rock is the source of the Quadrantids; possibly this asteroid is the burnt out core of the lost comet C/1490 Y1.
As viewed from mid-northern latitudes, we have to get up before dawn to see the Quadrantids at their best. This is because the radiant - that part of the sky from where the meteors to emanate - is down low on the northern horizon until about midnight, rising slowly higher as the night progresses. The growing light of dawn ends meteor observing usually by around 7 a.m. So, if the "Quads" are to be seen at all, some part of that 8-hour active period must fall between 2 and 7 a.m.
In one out of every three years, bright moonlight spoils the view. Over northern latitudes, early January often sees inclement/unsettled weather. It is not surprising then, that the Quadrantids are not as well-observed as some of the other annual meteor showers, but 2009 could be an exception.
Excellent prospects in 2009
According to the International Meteor Organization, maximum activity this year is expected on 4:50 a.m. Pacific Standard Time on Jan. 3. For those across the western half of the United States and Canada, the radiant will soar high in the eastern sky just prior to the onset of morning twilight. Over the eastern United States and Canada, the spike of activity is predicted to come after sunrise.
Quadrantid meteors are described as bright and bluish with long silvery trains. Some years produce a mere handful, but for favorably placed observers, an excellent meteor display may be in the offing; at greatest activity, Quadrantid rates will likely range from 30 to 60 per hour for eastern parts of the U.S. and Canada, to perhaps 60 to 120 per hour for the western United States and Canada. For those in Europe, the shower's sharp peak will likely come long after sunrise. Nonetheless, hourly rates of perhaps 15 to 30 may still be seen.
As far as the moon is concerned, it will not be a factor at all this year. It's a waxing crescent, two days from first quarter phase and will have set around 11 p.m. local time on Friday, Jan. 2, leaving the rest of the night dark for meteor watching.
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