Article on various mitigation topics and planetary defense conference in April 2009.
How to Defend Earth Against an Asteroid Strike
Brandon Keim
Wired.com
27 March 2009 02:20:05 PM
Link: Wired.com article
29 March 2009
28 March 2009
NEO News (03/27/09) To Catch a Falling Star
From Dave Morrison.
NEO News (03/27/09) To Catch a Falling Star
On October 6, 2008, the small NEA 2008TC3 was discovered approaching the Earth; 36 hours later it exploded in the atmosphere over the northern Sudan desert with energy of about 2KT. This represented the first detection and prediction of an impact before it happened. Now Nature reports on a remarkable continuation of this story with the identification and analysis of about 4 kg of fragments from 2008TC3. Below are the abstract from the Nature paper and several news reports on this unique sequence of events.
David Morrison
=========================
RECOVERED PIECES OF ASTEROID HOLD CLUES TO EARLY HISTORY
By Kenneth Chang
New York Times: March 25, 2009
Scientists who for the first time tracked an asteroid on a collision course with Earth, and watched as it exploded in the atmosphere, have now picked up some of the remnants on the ground. The discovery and analysis of the meteorites, reported in Thursday's issue of Nature, give scientists solid data on the composition of meteorites that originate from at least one type of asteroid, known as F-class.
Millions of asteroids, mostly small, whirl around the solar system, and over the years people have picked up tens of thousands of meteorites, the surviving rock fragments of asteroids that collide with Earth. "But we don't know where a single one of them comes from," said Michael E. Zolensky, a cosmic mineralogist at the Johnson Space Center in Houston, during a NASA-sponsored news conference on Wednesday.
That changed when Petrus M. Jenniskens, a scientist at the SETI Institute in Mountain View, Calif., organized a search team to comb through a Sudan desert to look for pieces of an asteroid that had been spotted less than a day before it hit Earth last year. "For the first time, we can dot the line between the meteorite in our hands and the asteroid astronomers saw in space," said Dr. Jenniskens, the lead author of the Nature paper.
The 280 pieces, about 10 pounds in total, are of a rare type of meteorite known as ureilites. The hodgepodge of minerals in ureilites indicates they were heated up but not fully melted, suggesting that they were once part of a much larger asteroid that possessed planet like geological processes.
Because ureilites are now linked to F-class asteroids, also rare, the hope is that scientists can now determine the history of asteroids, which contain some of the most primitive materials left over from the early solar system. "It's like the first step towards a Rosetta stone of understanding asteroids," Dr. Zolensky said.
The cascade of discovery started when Richard Kowalski, working with the of the University of Arizona, spotted a moving white dot on his computer screen late Oct. 5 at an observatory on Mount Lemmon outside Tucson. He sent the coordinates to the Minor Planet Center at the Harvard-Smithsonian Center for Astrophysics. A computer program at the center automatically calculates the orbits of reported projects, but it failed for the object Mr. Kowalski reported, because Earth's gravity appeared to be greatly distorting its orbit. The next morning, when Timothy B. Spahr, the center's director, took a closer look, the asteroid, designated 2008 TC3, looked as if it was being pulled directly into Earth.
Dr. Spahr notified Steven R. Chesley, a scientist in NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. "For the first time ever, I saw an impact probability of 100 percent pop up on the computer screen," Dr. Chesley said. "And this was, needless to say, the kind of thing that makes you sit up straight in the chair."
Because the asteroid was dim, the astronomers knew that it was small, about the size of a car and 80 tons, and would not cause any significant damage. Notice quickly spread, and asteroid watchers, professional and amateur, pointed their telescopes toward it.
With hundreds of observations coming in during the day, the computers at the Jet Propulsion Laboratory refined the trajectory. "Our last pre-impact prediction was accurate to about a kilometer and a couple tenths of a second in the impact time," Dr. Chesley said.
The asteroid disintegrated about 23 miles over the Nubian desert of northern Sudan about an hour before sunrise, 20 hours after Mr. Kowalski discovered it. It released the energy of one to two kilotons of TNT.
"We figured that probably was the end of the story," Dr. Chesley said. The expectation was that none of 2008 TC3 survived the passage through the atmosphere. But still, Dr. Jenniskens, an expert on meteor showers, wondered. "If we could find something, it would be tremendous," he said. "So you have to try. It was really a long shot."
In December, he flew to Sudan and organized a team of 45 students and staff members from the University of Khartoum to search through the desert for fragments of 2008 TC3. And they found the shiny black fragments that had come from space.
=======================
Nature 458, 485-488 (26 March 2009)
THE IMPACT AND RECOVERY OF ASTEROID 2008 TC3
P. Jenniskens1, M. H. Shaddad2, D. Numan2, S. Elsir3, A. M. Kudoda2, M. E. Zolensky4, L. Le4,5, G. A. Robinson4,5, J. M. Friedrich6,7, D. Rumble8, A. Steele8, S. R. Chesley9, A. Fitzsimmons10, S. Duddy10, H. H. Hsieh10, G. Ramsay11, P. G. Brown12, W. N. Edwards12, E. Tagliaferri13, M. B. Boslough14, R. E. Spalding14, R. Dantowitz15, M. Kozubal15, P. Pravec16, J. Borovicka16, Z. Charvat17, J. Vaubaillon18, J. Kuiper19, J. Albers1, J. L. Bishop1, R. L. Mancinelli1, S. A. Sandford20, S. N. Milam20, M. Nuevo20 & S. P. Worden20
In the absence of a firm link between individual meteorites and their asteroidal parent bodies, asteroids are typically characterized only by their light reflection properties, and grouped accordingly into classes1, 2, 3. On 6 October 2008, a small asteroid was discovered with a flat reflectance spectrum in the 554-995 nm wavelength range, and designated 2008 TC3 (refs 4-6). It subsequently hit the Earth. Because it exploded at 37 km altitude, no macroscopic fragments were expected to survive. Here we report that a dedicated search along the approach trajectory recovered 47 meteorites, fragments of a single body named Almahata Sitta, with a total mass of 3.95 kg. Analysis of one of these meteorites shows it to be an achondrite, a polymict ureilite, anomalous in its class: ultra-fine-grained and porous, with large carbonaceous grains. The combined asteroid and meteorite reflectance spectra identify the asteroid as F class3, now firmly linked to dark carbon-rich anomalous ureilites, a material so fragile it was not previously represented in meteorite collections.
========================
SKY FALLS, WHO CARES?
By John Tierney
New York Times: March 26, 2009
Now that we've tracked an asteroid on a collision course with Earth and recovered its debris, might we start taking these close encounters more seriously?
For the first time, scientists have tracked an asteroid headed to Earth, watched it explode in the atmosphere and picked up some of its remnants on the ground, as my colleague Ken Chang reports. This one, which disintegrated in about 23 miles over the Nubian desert of northern Sudan in October, was about the size of a car and weighed 70 tons - not enough to do much damage. But what happens when a bigger one arrives?
NASA has estimated that that there are close to 1,000 near-Earth space rocks at least a kilometer in diameter, my colleague Andy Revkin noted. And scientists have been finding evidence of more frequent catastrophic collisions in the past, as my colleague Sandra Blakeslee reported. Writing in the Atlantic Monthly last year, Gregg Easterbrook summarized the odds:
A generation ago, the standard assumption was that a dangerous object would strike Earth perhaps once in a million years. By the mid-1990s, researchers began to say that the threat was greater: perhaps a strike every 300,000 years. This winter, I asked William Ailor, an asteroid specialist at The Aerospace Corporation, a think tank for the Air Force, what he thought the risk was. Ailor's answer: a one-in-10 chance per century of a dangerous space-object strike.
[Morrison note: As reported here earlier, these impact statistics from Easterbrook could be highly misleading. The "dangerous object" hitting at million year intervals is an asteroid 1-2 km in diameter, enough to cause a global disaster. The "dangerous space-object crash" every thousand years is a Tunguska-class impact, which would do only local damage. The difference in mass (and energy) is about a factor of 100,000. In fact, our estimates of the probability of a hit at any particular size have gone down slightly over the past 20 years, not risen.]
Mr. Easterbrook argues that Congress should force NASA to switch its priorities from building a moon base to scanning the skies for asteroids and developing diversion techniques (like the gravity tractor discussed here at the Lab). I'm as enthusiastic about space travel as anyone, but I can see his point. Do you think that protecting the planet against asteroids is a more important role for the government than building a moon base? Would it be more important - and cost-effective - than most of the programs designed to deal with other environmental dangers?
If you're tired of waiting for governments to act, you can check out a group called Future Asteroid Interception Research, which is calling for citizens to take the financing initiative. Complaining that the White House is spending only $4 million per year on near-Earth object (NEO) research, the group argues:
Despite growing and alarming evidence of the dangers NEOs pose, this area of astronomy is still largely ignored. In 2004, when the Asian tsunami struck, "authorities" in the region deemed the relatively small cost of an early warning system not worth the investment as they believed such a catastrophe was not due for another 70 years. If the citizens of the affected countries had had foreknowledge of the impending disaster, don't you think the private sector would have done something about it? It's up to us to lend a hand in all areas of global concern when bureaucratically hamstrung governments dither. Fixing global warming will entail a monstrous effort. Hunting dangerous asteroids only costs ¤15.
Fifteen Euros works out to about $20. Does that seem worth it to you?
=======================
SURPRISE RECOVERY OF METEORITES FOLLOWING ASTEROID IMPACT
By Seth Shostak
Space News 26 March 2009
Fortunately, it wasn't large enough to require intervention by Bruce Willis, but asteroid 2008 TC3 is the first space rock to have been spotted before it crashed to Earth. It streaked into the skies over northern Sudan in the early morning of October 7, 2008, and then exploded at a high 37 km above the Nubian Desert, before the atmosphere could slow it appreciably. It was believed that the asteroid had fully disintegrated into dust.
A meteor astronomer with the SETI Institute's Carl Sagan Center, Peter Jenniskens, thought otherwise. After establishing a collaboration with Mauwia Shaddad of the Physics Department and Faculty of Sciences of the University of Khartoum, he traveled to the Sudan. The two researchers, together with students and staff from the university, collected nearly 280 pieces of the asteroid, strewn over 29 km of the Nubian Desert. Never before had meteorites been collected from such a high altitude explosion. As it turns out, the assembled remnants are unlike anything in our meteorite collections, and may be an important clue in unraveling the early history of the solar system.
"This was an extraordinary opportunity, for the first time, to bring into the lab actual pieces of an asteroid we had seen in space," comments Jenniskens, the lead author on a cover story article in the journal Nature that describes the recovery and analysis of 2008 TC3.
Picked up by Arizona's Catalina Sky Survey telescope on 6 October, 2008, the truck-sized asteroid abruptly ended its 4.5 billion year solar-system odyssey only 20 hours after discovery, when it broke apart in the African skies. The incoming asteroid was tracked by several groups of astronomers, including a team at the La Palma Observatory in the Canary Islands that was able to measure sunlight reflected by the object. Studying the reflected sunlight gives clues to the minerals at the surface of these objects. Astronomers group the asteroids into classes, and attempt to assign meteorite types to each class. But their ability to do this is often frustrated by layers of dust on the asteroid surfaces that scatter light in unpredictable ways.
Jenniskens teamed with planetary spectroscopist Janice Bishop of the SETI Institute to measure the reflection properties of the meteorite, and discovered that both the asteroid and its meteoritic remains reflected light in much the same way - similar to the known behavior of so-called F-class asteroids.
"F-class asteroids were long a mystery," Bishop notes. "Astronomers have measured their unique spectral properties with telescopes, but prior to 2008 TC3 there was no corresponding meteorite class, no rocks we could look at in the lab."
The good correspondence between telescopic and laboratory measurements for 2008 TC3 suggests that small asteroids don't have the troublesome dust layers, and may therefore be more suitable objects for establishing the link between asteroid type and meteorite properties. That would allow us to characterize asteroids from afar.
Rocco Mancinelli, a microbial ecologist at the SETI Institute's Carl Sagan Center, and a member of the research team, says that "2008 TC3 could serve as a Rosetta Stone, providing us with essential clues to the processes that built Earth and its planetary siblings."
In the dim past, as the solar system was taking shape, small dust particles stuck together to form larger bodies, a process of accumulation that eventually produced the asteroids. Some of these bodies collided so violently that they melted throughout.
2008 TC3 turns out to be an intermediate case, having been only partially melted. The resulting material produced what's called a polymict ureilite meteorite. The meteorites from 2008 TC3, now called "Almahata Sitta," are anomalous ureilites: very dark, porous, and rich in highly cooked carbon. This new material may serve to rule out many theories about the origin of ureilites.
In addition, knowing the nature of F-class asteroids could conceivably pay off in protecting Earth from dangerous impactors. The explosion of 2008 TC3 at high altitude indicates that it was of highly fragile construction. Its estimated mass was about 80 tons, of which only some 5 kg has been recovered on the ground. If at some future time we discover an F-class asteroid that's, say, several kilometers in size - one that could wipe out entire species - then we'll know its composition and can devise appropriate strategies to ward it off. Hitting such a fragile asteroid with an atomic bomb, as Bruce Willis might do, would merely turn it into a deadly swarm of shotgun pellets.
As efforts such as the Pan-STARRS project uncover smaller near-Earth asteroids, Jenniskens expects more incidents similar to 2008 TC3. "I look forward to getting a call from the next person to spot one of these," he says. "I would love to travel to the impact area in time to see the fireball in the sky, study its breakup and recover the pieces. If it's big enough, we may well find other fragile materials not yet in our meteorite collections."
--
+++++++++++++++++++++++++++++++++++++++++++
NEO News (now in its fourteenth year of distribution) is an informal compilation of news and opinion dealing with Near Earth Objects (NEOs) and their impacts. These opinions are the responsibility of the individual authors and do not represent the positions of NASA, Ames Research Center, the International Astronomical Union, or any other organization. To subscribe (or unsubscribe) contact dmorrison@arc.nasa.gov. For additional information, please see the website http://impact.arc.nasa.gov. If anyone wishes to copy or redistribute original material from these notes, fully or in part, please include this disclaimer.
NEO News (03/27/09) To Catch a Falling Star
On October 6, 2008, the small NEA 2008TC3 was discovered approaching the Earth; 36 hours later it exploded in the atmosphere over the northern Sudan desert with energy of about 2KT. This represented the first detection and prediction of an impact before it happened. Now Nature reports on a remarkable continuation of this story with the identification and analysis of about 4 kg of fragments from 2008TC3. Below are the abstract from the Nature paper and several news reports on this unique sequence of events.
David Morrison
=========================
RECOVERED PIECES OF ASTEROID HOLD CLUES TO EARLY HISTORY
By Kenneth Chang
New York Times: March 25, 2009
Scientists who for the first time tracked an asteroid on a collision course with Earth, and watched as it exploded in the atmosphere, have now picked up some of the remnants on the ground. The discovery and analysis of the meteorites, reported in Thursday's issue of Nature, give scientists solid data on the composition of meteorites that originate from at least one type of asteroid, known as F-class.
Millions of asteroids, mostly small, whirl around the solar system, and over the years people have picked up tens of thousands of meteorites, the surviving rock fragments of asteroids that collide with Earth. "But we don't know where a single one of them comes from," said Michael E. Zolensky, a cosmic mineralogist at the Johnson Space Center in Houston, during a NASA-sponsored news conference on Wednesday.
That changed when Petrus M. Jenniskens, a scientist at the SETI Institute in Mountain View, Calif., organized a search team to comb through a Sudan desert to look for pieces of an asteroid that had been spotted less than a day before it hit Earth last year. "For the first time, we can dot the line between the meteorite in our hands and the asteroid astronomers saw in space," said Dr. Jenniskens, the lead author of the Nature paper.
The 280 pieces, about 10 pounds in total, are of a rare type of meteorite known as ureilites. The hodgepodge of minerals in ureilites indicates they were heated up but not fully melted, suggesting that they were once part of a much larger asteroid that possessed planet like geological processes.
Because ureilites are now linked to F-class asteroids, also rare, the hope is that scientists can now determine the history of asteroids, which contain some of the most primitive materials left over from the early solar system. "It's like the first step towards a Rosetta stone of understanding asteroids," Dr. Zolensky said.
The cascade of discovery started when Richard Kowalski, working with the of the University of Arizona, spotted a moving white dot on his computer screen late Oct. 5 at an observatory on Mount Lemmon outside Tucson. He sent the coordinates to the Minor Planet Center at the Harvard-Smithsonian Center for Astrophysics. A computer program at the center automatically calculates the orbits of reported projects, but it failed for the object Mr. Kowalski reported, because Earth's gravity appeared to be greatly distorting its orbit. The next morning, when Timothy B. Spahr, the center's director, took a closer look, the asteroid, designated 2008 TC3, looked as if it was being pulled directly into Earth.
Dr. Spahr notified Steven R. Chesley, a scientist in NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. "For the first time ever, I saw an impact probability of 100 percent pop up on the computer screen," Dr. Chesley said. "And this was, needless to say, the kind of thing that makes you sit up straight in the chair."
Because the asteroid was dim, the astronomers knew that it was small, about the size of a car and 80 tons, and would not cause any significant damage. Notice quickly spread, and asteroid watchers, professional and amateur, pointed their telescopes toward it.
With hundreds of observations coming in during the day, the computers at the Jet Propulsion Laboratory refined the trajectory. "Our last pre-impact prediction was accurate to about a kilometer and a couple tenths of a second in the impact time," Dr. Chesley said.
The asteroid disintegrated about 23 miles over the Nubian desert of northern Sudan about an hour before sunrise, 20 hours after Mr. Kowalski discovered it. It released the energy of one to two kilotons of TNT.
"We figured that probably was the end of the story," Dr. Chesley said. The expectation was that none of 2008 TC3 survived the passage through the atmosphere. But still, Dr. Jenniskens, an expert on meteor showers, wondered. "If we could find something, it would be tremendous," he said. "So you have to try. It was really a long shot."
In December, he flew to Sudan and organized a team of 45 students and staff members from the University of Khartoum to search through the desert for fragments of 2008 TC3. And they found the shiny black fragments that had come from space.
=======================
Nature 458, 485-488 (26 March 2009)
THE IMPACT AND RECOVERY OF ASTEROID 2008 TC3
P. Jenniskens1, M. H. Shaddad2, D. Numan2, S. Elsir3, A. M. Kudoda2, M. E. Zolensky4, L. Le4,5, G. A. Robinson4,5, J. M. Friedrich6,7, D. Rumble8, A. Steele8, S. R. Chesley9, A. Fitzsimmons10, S. Duddy10, H. H. Hsieh10, G. Ramsay11, P. G. Brown12, W. N. Edwards12, E. Tagliaferri13, M. B. Boslough14, R. E. Spalding14, R. Dantowitz15, M. Kozubal15, P. Pravec16, J. Borovicka16, Z. Charvat17, J. Vaubaillon18, J. Kuiper19, J. Albers1, J. L. Bishop1, R. L. Mancinelli1, S. A. Sandford20, S. N. Milam20, M. Nuevo20 & S. P. Worden20
In the absence of a firm link between individual meteorites and their asteroidal parent bodies, asteroids are typically characterized only by their light reflection properties, and grouped accordingly into classes1, 2, 3. On 6 October 2008, a small asteroid was discovered with a flat reflectance spectrum in the 554-995 nm wavelength range, and designated 2008 TC3 (refs 4-6). It subsequently hit the Earth. Because it exploded at 37 km altitude, no macroscopic fragments were expected to survive. Here we report that a dedicated search along the approach trajectory recovered 47 meteorites, fragments of a single body named Almahata Sitta, with a total mass of 3.95 kg. Analysis of one of these meteorites shows it to be an achondrite, a polymict ureilite, anomalous in its class: ultra-fine-grained and porous, with large carbonaceous grains. The combined asteroid and meteorite reflectance spectra identify the asteroid as F class3, now firmly linked to dark carbon-rich anomalous ureilites, a material so fragile it was not previously represented in meteorite collections.
========================
SKY FALLS, WHO CARES?
By John Tierney
New York Times: March 26, 2009
Now that we've tracked an asteroid on a collision course with Earth and recovered its debris, might we start taking these close encounters more seriously?
For the first time, scientists have tracked an asteroid headed to Earth, watched it explode in the atmosphere and picked up some of its remnants on the ground, as my colleague Ken Chang reports. This one, which disintegrated in about 23 miles over the Nubian desert of northern Sudan in October, was about the size of a car and weighed 70 tons - not enough to do much damage. But what happens when a bigger one arrives?
NASA has estimated that that there are close to 1,000 near-Earth space rocks at least a kilometer in diameter, my colleague Andy Revkin noted. And scientists have been finding evidence of more frequent catastrophic collisions in the past, as my colleague Sandra Blakeslee reported. Writing in the Atlantic Monthly last year, Gregg Easterbrook summarized the odds:
A generation ago, the standard assumption was that a dangerous object would strike Earth perhaps once in a million years. By the mid-1990s, researchers began to say that the threat was greater: perhaps a strike every 300,000 years. This winter, I asked William Ailor, an asteroid specialist at The Aerospace Corporation, a think tank for the Air Force, what he thought the risk was. Ailor's answer: a one-in-10 chance per century of a dangerous space-object strike.
[Morrison note: As reported here earlier, these impact statistics from Easterbrook could be highly misleading. The "dangerous object" hitting at million year intervals is an asteroid 1-2 km in diameter, enough to cause a global disaster. The "dangerous space-object crash" every thousand years is a Tunguska-class impact, which would do only local damage. The difference in mass (and energy) is about a factor of 100,000. In fact, our estimates of the probability of a hit at any particular size have gone down slightly over the past 20 years, not risen.]
Mr. Easterbrook argues that Congress should force NASA to switch its priorities from building a moon base to scanning the skies for asteroids and developing diversion techniques (like the gravity tractor discussed here at the Lab). I'm as enthusiastic about space travel as anyone, but I can see his point. Do you think that protecting the planet against asteroids is a more important role for the government than building a moon base? Would it be more important - and cost-effective - than most of the programs designed to deal with other environmental dangers?
If you're tired of waiting for governments to act, you can check out a group called Future Asteroid Interception Research, which is calling for citizens to take the financing initiative. Complaining that the White House is spending only $4 million per year on near-Earth object (NEO) research, the group argues:
Despite growing and alarming evidence of the dangers NEOs pose, this area of astronomy is still largely ignored. In 2004, when the Asian tsunami struck, "authorities" in the region deemed the relatively small cost of an early warning system not worth the investment as they believed such a catastrophe was not due for another 70 years. If the citizens of the affected countries had had foreknowledge of the impending disaster, don't you think the private sector would have done something about it? It's up to us to lend a hand in all areas of global concern when bureaucratically hamstrung governments dither. Fixing global warming will entail a monstrous effort. Hunting dangerous asteroids only costs ¤15.
Fifteen Euros works out to about $20. Does that seem worth it to you?
=======================
SURPRISE RECOVERY OF METEORITES FOLLOWING ASTEROID IMPACT
By Seth Shostak
Space News 26 March 2009
Fortunately, it wasn't large enough to require intervention by Bruce Willis, but asteroid 2008 TC3 is the first space rock to have been spotted before it crashed to Earth. It streaked into the skies over northern Sudan in the early morning of October 7, 2008, and then exploded at a high 37 km above the Nubian Desert, before the atmosphere could slow it appreciably. It was believed that the asteroid had fully disintegrated into dust.
A meteor astronomer with the SETI Institute's Carl Sagan Center, Peter Jenniskens, thought otherwise. After establishing a collaboration with Mauwia Shaddad of the Physics Department and Faculty of Sciences of the University of Khartoum, he traveled to the Sudan. The two researchers, together with students and staff from the university, collected nearly 280 pieces of the asteroid, strewn over 29 km of the Nubian Desert. Never before had meteorites been collected from such a high altitude explosion. As it turns out, the assembled remnants are unlike anything in our meteorite collections, and may be an important clue in unraveling the early history of the solar system.
"This was an extraordinary opportunity, for the first time, to bring into the lab actual pieces of an asteroid we had seen in space," comments Jenniskens, the lead author on a cover story article in the journal Nature that describes the recovery and analysis of 2008 TC3.
Picked up by Arizona's Catalina Sky Survey telescope on 6 October, 2008, the truck-sized asteroid abruptly ended its 4.5 billion year solar-system odyssey only 20 hours after discovery, when it broke apart in the African skies. The incoming asteroid was tracked by several groups of astronomers, including a team at the La Palma Observatory in the Canary Islands that was able to measure sunlight reflected by the object. Studying the reflected sunlight gives clues to the minerals at the surface of these objects. Astronomers group the asteroids into classes, and attempt to assign meteorite types to each class. But their ability to do this is often frustrated by layers of dust on the asteroid surfaces that scatter light in unpredictable ways.
Jenniskens teamed with planetary spectroscopist Janice Bishop of the SETI Institute to measure the reflection properties of the meteorite, and discovered that both the asteroid and its meteoritic remains reflected light in much the same way - similar to the known behavior of so-called F-class asteroids.
"F-class asteroids were long a mystery," Bishop notes. "Astronomers have measured their unique spectral properties with telescopes, but prior to 2008 TC3 there was no corresponding meteorite class, no rocks we could look at in the lab."
The good correspondence between telescopic and laboratory measurements for 2008 TC3 suggests that small asteroids don't have the troublesome dust layers, and may therefore be more suitable objects for establishing the link between asteroid type and meteorite properties. That would allow us to characterize asteroids from afar.
Rocco Mancinelli, a microbial ecologist at the SETI Institute's Carl Sagan Center, and a member of the research team, says that "2008 TC3 could serve as a Rosetta Stone, providing us with essential clues to the processes that built Earth and its planetary siblings."
In the dim past, as the solar system was taking shape, small dust particles stuck together to form larger bodies, a process of accumulation that eventually produced the asteroids. Some of these bodies collided so violently that they melted throughout.
2008 TC3 turns out to be an intermediate case, having been only partially melted. The resulting material produced what's called a polymict ureilite meteorite. The meteorites from 2008 TC3, now called "Almahata Sitta," are anomalous ureilites: very dark, porous, and rich in highly cooked carbon. This new material may serve to rule out many theories about the origin of ureilites.
In addition, knowing the nature of F-class asteroids could conceivably pay off in protecting Earth from dangerous impactors. The explosion of 2008 TC3 at high altitude indicates that it was of highly fragile construction. Its estimated mass was about 80 tons, of which only some 5 kg has been recovered on the ground. If at some future time we discover an F-class asteroid that's, say, several kilometers in size - one that could wipe out entire species - then we'll know its composition and can devise appropriate strategies to ward it off. Hitting such a fragile asteroid with an atomic bomb, as Bruce Willis might do, would merely turn it into a deadly swarm of shotgun pellets.
As efforts such as the Pan-STARRS project uncover smaller near-Earth asteroids, Jenniskens expects more incidents similar to 2008 TC3. "I look forward to getting a call from the next person to spot one of these," he says. "I would love to travel to the impact area in time to see the fireball in the sky, study its breakup and recover the pieces. If it's big enough, we may well find other fragile materials not yet in our meteorite collections."
--
+++++++++++++++++++++++++++++++++++++++++++
NEO News (now in its fourteenth year of distribution) is an informal compilation of news and opinion dealing with Near Earth Objects (NEOs) and their impacts. These opinions are the responsibility of the individual authors and do not represent the positions of NASA, Ames Research Center, the International Astronomical Union, or any other organization. To subscribe (or unsubscribe) contact dmorrison@arc.nasa.gov. For additional information, please see the website http://impact.arc.nasa.gov. If anyone wishes to copy or redistribute original material from these notes, fully or in part, please include this disclaimer.
27 March 2009
Paper: Tunguska-1908 and similar events in light of the New Explosive Cosmogony of minor bodies
Selections from an article on a new technical paper about the Tunguska event. The author makes the claim that the Tunguska event was caused by a comet that hit at a tangent to the Earth's surface, and essentially bounced off the atmosphere. Selections from the article follows...
Despite a century of study, many aspects of the Tunguska event are still unexplained. For example, the explosion released more energy than a thousand Hiroshima-type atom bombs and yet left no crater. A similar-sized object is thought to have hit North America some 12 000 years ago, triggering the megafaunal extinction and widespread cooling. And yet the Tunguska event seems to have left our climate intact.
Now a new analysis by Edward Drobyshevski of the Russian Academy of Sciences in St Petersburg Russia claims to have solved these problems. Drobyshevski concludes that the object that hit in 1908 was a comet (as have many scientists before him). But unlike the others, he has been able to calculate that this comet hit the Earth's atmosphere almost at a tangent and broke apart.
The larger part of this comet skipped off the atmosphere, back into an Earth-crossing orbit (we should expect to find it nearby, predicts Drobyshevski).The smaller part rapidly heated up above Russia before exploding in the atmosphere over Tunguska.
The key to why it left so little lasting damage is the nature of the explosion, says Drobyshevski. And the key to that is our improved understanding of the chemical make up of comets. He says the comet would have had a high hydrogen peroxide content and this would have dissociated explosively as it heated up to produce oxygen and water, breaking the comet apart. It was this explosion that devastated Tunguska.
"Significantly, the energy of the chemical explosion is substantially lower than the kinetic energy of the body," says Drobyshevski.
This explains the comet's relatively benign affect on the planet and solves many of mysteries associated with the event, he says.
Link: Technology Review Article
Link: Paper Abstract
Link: Paper (PDF)
Despite a century of study, many aspects of the Tunguska event are still unexplained. For example, the explosion released more energy than a thousand Hiroshima-type atom bombs and yet left no crater. A similar-sized object is thought to have hit North America some 12 000 years ago, triggering the megafaunal extinction and widespread cooling. And yet the Tunguska event seems to have left our climate intact.
Now a new analysis by Edward Drobyshevski of the Russian Academy of Sciences in St Petersburg Russia claims to have solved these problems. Drobyshevski concludes that the object that hit in 1908 was a comet (as have many scientists before him). But unlike the others, he has been able to calculate that this comet hit the Earth's atmosphere almost at a tangent and broke apart.
The larger part of this comet skipped off the atmosphere, back into an Earth-crossing orbit (we should expect to find it nearby, predicts Drobyshevski).The smaller part rapidly heated up above Russia before exploding in the atmosphere over Tunguska.
The key to why it left so little lasting damage is the nature of the explosion, says Drobyshevski. And the key to that is our improved understanding of the chemical make up of comets. He says the comet would have had a high hydrogen peroxide content and this would have dissociated explosively as it heated up to produce oxygen and water, breaking the comet apart. It was this explosion that devastated Tunguska.
"Significantly, the energy of the chemical explosion is substantially lower than the kinetic energy of the body," says Drobyshevski.
This explains the comet's relatively benign affect on the planet and solves many of mysteries associated with the event, he says.
Link: Technology Review Article
Link: Paper Abstract
Link: Paper (PDF)
26 March 2009
Updated list of articles on 2008 TC3 Announcement
The very first meteorite found by student Mohammed Alameen in the late afternoon of December 6, 2008. Credit: SETI
A meteorite from an unusually well-tracked asteroid lies in the Nubian Desert in northern Sudan. The deep black color tells researchers that the rock is rich in carbon. (Credit: Nature)
Here are selected news articles about the NASA announcement of the 2008 TC3 meteorite discovery (will be updated throughout the day)
"Surprise Recovery of Meteorites Following Asteroid Impact"
Seth Shostak
Space.com
26 March 2009 10:41 AM ET
Link: Space.com article
Catch a Falling Star: The Remarkable Asteroid 2008 TC3
Kelly Beatty
Sky and Telescope
24 March 2009
Link: Sky and Telescope Article
Meteorites in Africa Traced to Asteroid "Parent"
Anne Minard
National Geographic News
25 March 2009
Link: http://news.nationalgeographic.com/news/2009/03/090325-asteroid-meteorites-parent.html
Scientists Examine Asteroid Remains
Kenneth Chang
New York Times
25 March 2009
Link: New York Times Article
Space 'Rosetta Stone' Unlike Anything Seen Before
Andrea Thompson
Live Science
25 March 2009 02:00 pm ET
Link: Live Science Article
Meteorite hunters 'strike gold' in Sudan
Rachel Courtland
New Scientist
20 March 2009 19:27
Link: New Scientist Article
80-ton asteroid's impact recorded (with video animation and interview of Queen's University student)
BBC News
25 March 2009 17:59 GMT
Link: BBC News Article
Asteroid Impact Helps Trace Meteorite Origins
Science News
ScienceDaily
25 March 2009
Link: Science News Article
Astronomers catch a shooting star for 1st time
Seth Borenstein
Associated Press (AP)
25 March 2009
Link: AP Article
Astronomers track asteroid's collision with Earth
Lewis Smith
Times Online
25 March 2009
Link: Times Online article
25 March 2009
Nature Paper from Jenniskens, et al on 2008 TC3
Here is the information for the Jenniskens, et al paper in the Journal nature on 2008 TC3.
A fragment of asteroid 2008 TC3 as found in the desert in northern Sudan in March 2009. The asteroid disintegrated at an altitude of 37 km in October 2008 but, remarkably, 47 fragments with a total mass of 3.95 kg have been recovered, and Jenniskens et al. have identified the material as surface matter from a class ‘F’ asteroid, a type not previously represented in meteorite collections. [Credit: Peter Jenniskens/ SETI Institute.]
Nature 458, 485-488 (26 March 2009)
Received 6 February 2009
Accepted 20 February 2009
Letter
The impact and recovery of asteroid 2008 TC3
P. Jenniskens1, M. H. Shaddad2, D. Numan2, S. Elsir3, A. M. Kudoda2, M. E. Zolensky4, L. Le4,5, G. A. Robinson4,5, J. M. Friedrich6,7, D. Rumble8, A. Steele8, S. R. Chesley9, A. Fitzsimmons10, S. Duddy10, H. H. Hsieh10, G. Ramsay11, P. G. Brown12, W. N. Edwards12, E. Tagliaferri13, M. B. Boslough14, R. E. Spalding14, R. Dantowitz15, M. Kozubal15, P. Pravec16, J. Borovicka16, Z. Charvat17, J. Vaubaillon18, J. Kuiper19, J. Albers1, J. L. Bishop1, R. L. Mancinelli1, S. A. Sandford20, S. N. Milam20, M. Nuevo20 & S. P. Worden20
1. SETI Institute, Carl Sagan Center, 515 North Whisman Road, Mountain View, California 94043, USA
2. Physics Department, University of Khartoum, PO Box 321, Khartoum 11115, Sudan
3. Physics Department, Juba University, Juba, Sudan
4. NASA Johnson Space Center, Mail Code KT, Houston, Texas 77058, USA
5. Jacobs Technologies Engineering Science Contact Group (ESCG), Johnson Space Center, Houston, Texas 77058, USA
6. Department of Chemistry, Fordham University, 441 East Fordham Road, Bronx, New York 10458, USA
7. Department of Earth and Planetary Sciences, American Museum of Natural History, 79th Street at Central Park West, New York, New York 10024, USA
8. Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington DC 20015-1305, USA
9. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
10. School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN, UK
11. Armagh Observatory, College Hill, Armagh BT61 9DG, UK
12. Department of Physics and Astronomy, University of Western Ontario, London, Ontario N6A 3K7, Canada
13. ET Space Systems, 5990 Worth Way, Camarillo, California 93012, USA
14. Sandia National Laboratories, PO Box 5800, Albuquerque, New Mexico 87185, USA
15. Clay Center Observatory, Dexter and Southfield Schools, 20 Newton Street, Brookline, Massachusetts 02445, USA
16. Astronomical Institute of the Academy of Sciences, Fric caronova 298, 25165 Ondr caronejov Observatory, Czech Republic
17. Czech Hydrometeorological Institute, Na Sabatce 17, 143 06 Praha 4, Czech Republic
18. Institut de Mécanique Céleste et de Calcul des Éphémérides, 77 avenue Denfert-Rochereau, 75014 Paris, France
19. Dutch Meteor Society, Akker 141, 3732 XD De Bilt, The Netherlands
20. NASA Ames Research Center, Mail Stop 245-6, Moffett Field, California 94035, USA
Correspondence to: P. Jenniskens1 Correspondence and requests for materials should be addressed to P.J. (Email: Petrus.M.Jenniskens@nasa.gov).
Abstract:
In the absence of a firm link between individual meteorites and their asteroidal parent bodies, asteroids are typically characterized only by their light reflection properties, and grouped accordingly into classes1, 2, 3. On 6 October 2008, a small asteroid was discovered with a flat reflectance spectrum in the 554–995 nm wavelength range, and designated 2008 TC3 (refs 4–6). It subsequently hit the Earth. Because it exploded at 37 km altitude, no macroscopic fragments were expected to survive. Here we report that a dedicated search along the approach trajectory recovered 47 meteorites, fragments of a single body named Almahata Sitta, with a total mass of 3.95 kg. Analysis of one of these meteorites shows it to be an achondrite, a polymict ureilite, anomalous in its class: ultra-fine-grained and porous, with large carbonaceous grains. The combined asteroid and meteorite reflectance spectra identify the asteroid as F class3, now firmly linked to dark carbon-rich anomalous ureilites, a material so fragile it was not previously represented in meteorite collections.
Link: Nature paper link
A fragment of asteroid 2008 TC3 as found in the desert in northern Sudan in March 2009. The asteroid disintegrated at an altitude of 37 km in October 2008 but, remarkably, 47 fragments with a total mass of 3.95 kg have been recovered, and Jenniskens et al. have identified the material as surface matter from a class ‘F’ asteroid, a type not previously represented in meteorite collections. [Credit: Peter Jenniskens/ SETI Institute.]
Nature 458, 485-488 (26 March 2009)
Received 6 February 2009
Accepted 20 February 2009
Letter
The impact and recovery of asteroid 2008 TC3
P. Jenniskens1, M. H. Shaddad2, D. Numan2, S. Elsir3, A. M. Kudoda2, M. E. Zolensky4, L. Le4,5, G. A. Robinson4,5, J. M. Friedrich6,7, D. Rumble8, A. Steele8, S. R. Chesley9, A. Fitzsimmons10, S. Duddy10, H. H. Hsieh10, G. Ramsay11, P. G. Brown12, W. N. Edwards12, E. Tagliaferri13, M. B. Boslough14, R. E. Spalding14, R. Dantowitz15, M. Kozubal15, P. Pravec16, J. Borovicka16, Z. Charvat17, J. Vaubaillon18, J. Kuiper19, J. Albers1, J. L. Bishop1, R. L. Mancinelli1, S. A. Sandford20, S. N. Milam20, M. Nuevo20 & S. P. Worden20
1. SETI Institute, Carl Sagan Center, 515 North Whisman Road, Mountain View, California 94043, USA
2. Physics Department, University of Khartoum, PO Box 321, Khartoum 11115, Sudan
3. Physics Department, Juba University, Juba, Sudan
4. NASA Johnson Space Center, Mail Code KT, Houston, Texas 77058, USA
5. Jacobs Technologies Engineering Science Contact Group (ESCG), Johnson Space Center, Houston, Texas 77058, USA
6. Department of Chemistry, Fordham University, 441 East Fordham Road, Bronx, New York 10458, USA
7. Department of Earth and Planetary Sciences, American Museum of Natural History, 79th Street at Central Park West, New York, New York 10024, USA
8. Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington DC 20015-1305, USA
9. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
10. School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN, UK
11. Armagh Observatory, College Hill, Armagh BT61 9DG, UK
12. Department of Physics and Astronomy, University of Western Ontario, London, Ontario N6A 3K7, Canada
13. ET Space Systems, 5990 Worth Way, Camarillo, California 93012, USA
14. Sandia National Laboratories, PO Box 5800, Albuquerque, New Mexico 87185, USA
15. Clay Center Observatory, Dexter and Southfield Schools, 20 Newton Street, Brookline, Massachusetts 02445, USA
16. Astronomical Institute of the Academy of Sciences, Fric caronova 298, 25165 Ondr caronejov Observatory, Czech Republic
17. Czech Hydrometeorological Institute, Na Sabatce 17, 143 06 Praha 4, Czech Republic
18. Institut de Mécanique Céleste et de Calcul des Éphémérides, 77 avenue Denfert-Rochereau, 75014 Paris, France
19. Dutch Meteor Society, Akker 141, 3732 XD De Bilt, The Netherlands
20. NASA Ames Research Center, Mail Stop 245-6, Moffett Field, California 94035, USA
Correspondence to: P. Jenniskens1 Correspondence and requests for materials should be addressed to P.J. (Email: Petrus.M.Jenniskens@nasa.gov).
Abstract:
In the absence of a firm link between individual meteorites and their asteroidal parent bodies, asteroids are typically characterized only by their light reflection properties, and grouped accordingly into classes1, 2, 3. On 6 October 2008, a small asteroid was discovered with a flat reflectance spectrum in the 554–995 nm wavelength range, and designated 2008 TC3 (refs 4–6). It subsequently hit the Earth. Because it exploded at 37 km altitude, no macroscopic fragments were expected to survive. Here we report that a dedicated search along the approach trajectory recovered 47 meteorites, fragments of a single body named Almahata Sitta, with a total mass of 3.95 kg. Analysis of one of these meteorites shows it to be an achondrite, a polymict ureilite, anomalous in its class: ultra-fine-grained and porous, with large carbonaceous grains. The combined asteroid and meteorite reflectance spectra identify the asteroid as F class3, now firmly linked to dark carbon-rich anomalous ureilites, a material so fragile it was not previously represented in meteorite collections.
Link: Nature paper link
“First step to a Rosetta stone of asteroids”: Selected notes from NASA Media Advisory on 2008 TC3
Selected notes from NASA Media Advisory on 2008 TC3 (including comments from the question and answer session, notes: these are quick and limited notes and not meant to be a complete transcript, any errors are my own):
Panelists:
- Peter Jenniskens, meteor astronomer at NASA's Ames Research Center, Moffett Field, Calif., and the SETI Institute in Mountain View, Calif.
- Steve Chesley, scientist in NASA's Near-Earth Object Program Office at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
- Michael Zolensky, cosmic mineralogist at NASA's Johnson Space Center in Houston
- Lucy McFadden, professor of astronomy at the University of Maryland in College Park
Peter Jenniskens:
Large effort from Muawia Shaddad of the University of Khartoum, Sudan and his students to recover sample, 2008 Tc3 meteorite from 2008 TC3 is named after Station 6, Arabic name, NASA is finding 15 NEAs per month. On Oct. 5 2008: Catalina Sky Survey finds object, impact would be 20 hours later, 2008 TC3 is of a very rare calls F-class, in the past the orbit was more eccentric, 9998 which is also an F-type could originate from the same debris field, Mohammed Alameen was one of the key students who was very helpful in finding the asteroid, biggest sample size obtained was 280 grams, asteroid of about this size hit the Earth about once a year, F-type asteroid are very rare – of all the asteroids (1.3% are F-class) – maybe because they are so dark (some observational bias perhaps), after second search in December, large fragments found south of trajectory, wonder if spread out widely just south of track, went back to Sudan with 52 people – vertical scan of trajectory, end of that search found 280 meteorites, total mass is 5 kg, tiny fraction of overall, actual recovery is a little south of trajectory
Steve Chesley:
Steve Chesley got phone call 8 hours prior to impact from Minor Planet Center, saw impact probability at 100% on screen, plotted and found impact location less than 9 hours to impact, dozens of observatories then observed and reported tracking measurements, last pre-impact prediction was about 1 km off in position and a coupled of seconds off (in terms of impact time) which is very good, impact energy over 1000 tons of TNT, figured that was the end of the story, several weeks later got a request from Peter Jenniskens about impact and trying to find it, spin measurements for objects this small not normally known (have an estimate for this object), meteorites do not alter that much when entering the atmosphere, most meteorites are relatively unchanged, different this time, probably know which asteroid this may have come from, normally difficult to connect spectra of meteorites and then asteroids – can now do that (first time), “first step to a Rosetta stone of asteroids”
Michael Zolensky:
Received samples from Peter for analysis, analysis group included NASA JSC, NASA Ames, Fordam University, and Carnegie Institution, meteor belongs to a rare group, novel properties not found in other meteorites dark areas are large pores lined with iron-magnesium silicon grains, due to volcanic properties, Carbonaceous materials, images 3c very porous, up to 40% porosity, must have been more porous still prior to impact, could have been in a single piece of a larger asteroid from long ago, this type of F-type normally contains Carbonaceous chondrites, could be related to CC (c-class asteroid), Ureilite type asteroid, nanometer sized diamonds in there, chunks of large graphite in there, possibility of mixing of different types of materials – happening at original large parent body, asteroids like planets 4.5 billion years ago, very hot and then cooled off
Lucy McFadden:
There may be more F-type asteroids since they are very dark, many larger bodies in the asteroid belt 4.5 billion years ago, smaller fragments formed over time from collisions, learned that there may be many more planets than today, many more larger bodies before, would call the hundred to a thousand kilometers of size of parent body, signature of 2008 TC3 indicates it came from such a body
Panelists:
- Peter Jenniskens, meteor astronomer at NASA's Ames Research Center, Moffett Field, Calif., and the SETI Institute in Mountain View, Calif.
- Steve Chesley, scientist in NASA's Near-Earth Object Program Office at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
- Michael Zolensky, cosmic mineralogist at NASA's Johnson Space Center in Houston
- Lucy McFadden, professor of astronomy at the University of Maryland in College Park
Peter Jenniskens:
Large effort from Muawia Shaddad of the University of Khartoum, Sudan and his students to recover sample, 2008 Tc3 meteorite from 2008 TC3 is named after Station 6, Arabic name, NASA is finding 15 NEAs per month. On Oct. 5 2008: Catalina Sky Survey finds object, impact would be 20 hours later, 2008 TC3 is of a very rare calls F-class, in the past the orbit was more eccentric, 9998 which is also an F-type could originate from the same debris field, Mohammed Alameen was one of the key students who was very helpful in finding the asteroid, biggest sample size obtained was 280 grams, asteroid of about this size hit the Earth about once a year, F-type asteroid are very rare – of all the asteroids (1.3% are F-class) – maybe because they are so dark (some observational bias perhaps), after second search in December, large fragments found south of trajectory, wonder if spread out widely just south of track, went back to Sudan with 52 people – vertical scan of trajectory, end of that search found 280 meteorites, total mass is 5 kg, tiny fraction of overall, actual recovery is a little south of trajectory
Steve Chesley:
Steve Chesley got phone call 8 hours prior to impact from Minor Planet Center, saw impact probability at 100% on screen, plotted and found impact location less than 9 hours to impact, dozens of observatories then observed and reported tracking measurements, last pre-impact prediction was about 1 km off in position and a coupled of seconds off (in terms of impact time) which is very good, impact energy over 1000 tons of TNT, figured that was the end of the story, several weeks later got a request from Peter Jenniskens about impact and trying to find it, spin measurements for objects this small not normally known (have an estimate for this object), meteorites do not alter that much when entering the atmosphere, most meteorites are relatively unchanged, different this time, probably know which asteroid this may have come from, normally difficult to connect spectra of meteorites and then asteroids – can now do that (first time), “first step to a Rosetta stone of asteroids”
Michael Zolensky:
Received samples from Peter for analysis, analysis group included NASA JSC, NASA Ames, Fordam University, and Carnegie Institution, meteor belongs to a rare group, novel properties not found in other meteorites dark areas are large pores lined with iron-magnesium silicon grains, due to volcanic properties, Carbonaceous materials, images 3c very porous, up to 40% porosity, must have been more porous still prior to impact, could have been in a single piece of a larger asteroid from long ago, this type of F-type normally contains Carbonaceous chondrites, could be related to CC (c-class asteroid), Ureilite type asteroid, nanometer sized diamonds in there, chunks of large graphite in there, possibility of mixing of different types of materials – happening at original large parent body, asteroids like planets 4.5 billion years ago, very hot and then cooled off
Lucy McFadden:
There may be more F-type asteroids since they are very dark, many larger bodies in the asteroid belt 4.5 billion years ago, smaller fragments formed over time from collisions, learned that there may be many more planets than today, many more larger bodies before, would call the hundred to a thousand kilometers of size of parent body, signature of 2008 TC3 indicates it came from such a body
Updates from NASA Media Advisory on 2008 TC3
Here are images from the NASA Media Advisory.
Link: Images from Media Advisory
Image 1A
Infrared image taken by the Meteosat 8 satellite of asteroid 2008 TC3 exploding. Image courtesy: EUMESTAT
› Larger view
Image 1B
Image taken by a cellphone of the contrail left by 2008 TC3 during its decent. Image courtesy: Shaddad
› Full resolution
Image 1C
University of Khartoum students and staff prepare to search for meteorite remnants
› Full resolution
Image 1D
The Nubian desert
› Full resolution
Image 1E
A typical example of a meteorite remnant linked to asteroid 2008 TC3, with a dark scruffy texture.
› Full resolution
Image 1F
Muawia Shaddad of the University of Khartoum, Sudan and NASA meteor astronomer Peter Jenniskens join students of the University of Khartoum at the location of one of the larger finds from the first search campaign, Dec. 8, 2008.
Steve Chesley
Image 2A
Telescope of the Catalina Sky Survey. Image courtesy: NASA/CSS
› Larger view
Image 2B
› Play animation
Detecting asteroid 2008 TC3 in space.
Image 2C
Impact trajectory of asteroid 2008 TC3.
Image 2D
This space-based view of the Nubian Desert shows altitude in kilometers (in white circles) and meteor locations in red. Image courtesy NASA Ames/SETI/JPL | › Full resolution
Mike Zolensky
Image 3A
Meteorite sample
Image 3B
Meteorite sample linked to asteroid TC3
› Larger view
Image 3C
Electron views of meteorite samples
› Larger view
Image 3D
Asteroid types
› Larger view
Lucy McFadden
Image 4A
Meteorite types
› Larger view
Image 4B
Near-Earth asteroids
Image 4C
› Play animation
Animation of Near-Earth objects that approached within 20 million kilometers (12.4 million miles) of Earth between the dates of July 2007 and June 2008. Image courtesy: IAU/Harvard/MPC
Supplemental Images
Image 5A
› Full resolution
Image 5B
› Full resolution
Link: Images from Media Advisory
Image 1A
Infrared image taken by the Meteosat 8 satellite of asteroid 2008 TC3 exploding. Image courtesy: EUMESTAT
› Larger view
Image 1B
Image taken by a cellphone of the contrail left by 2008 TC3 during its decent. Image courtesy: Shaddad
› Full resolution
Image 1C
University of Khartoum students and staff prepare to search for meteorite remnants
› Full resolution
Image 1D
The Nubian desert
› Full resolution
Image 1E
A typical example of a meteorite remnant linked to asteroid 2008 TC3, with a dark scruffy texture.
› Full resolution
Image 1F
Muawia Shaddad of the University of Khartoum, Sudan and NASA meteor astronomer Peter Jenniskens join students of the University of Khartoum at the location of one of the larger finds from the first search campaign, Dec. 8, 2008.
Steve Chesley
Image 2A
Telescope of the Catalina Sky Survey. Image courtesy: NASA/CSS
› Larger view
Image 2B
› Play animation
Detecting asteroid 2008 TC3 in space.
Image 2C
Impact trajectory of asteroid 2008 TC3.
Image 2D
This space-based view of the Nubian Desert shows altitude in kilometers (in white circles) and meteor locations in red. Image courtesy NASA Ames/SETI/JPL | › Full resolution
Mike Zolensky
Image 3A
Meteorite sample
Image 3B
Meteorite sample linked to asteroid TC3
› Larger view
Image 3C
Electron views of meteorite samples
› Larger view
Image 3D
Asteroid types
› Larger view
Lucy McFadden
Image 4A
Meteorite types
› Larger view
Image 4B
Near-Earth asteroids
Image 4C
› Play animation
Animation of Near-Earth objects that approached within 20 million kilometers (12.4 million miles) of Earth between the dates of July 2007 and June 2008. Image courtesy: IAU/Harvard/MPC
Supplemental Images
Image 5A
› Full resolution
Image 5B
› Full resolution
Kenneth Change NYTimes Article on 2008 TC3
Here is the complete article from Kenneth Chang that summarizes the 2008 TC3 discovery.
Scientists Examine Asteroid Remains
Kenneth Chang
New York Times
25 March 2009
Scientists who for the first time tracked an asteroid on a collision course with Earth, and watched as it exploded in the atmosphere, have now picked up some of the remnants on the ground. The discovery and analysis of the meteorites, reported in Thursday’s issue of the journal Nature, give scientists solid data on the composition of meteorites that originate from what are known as F-class asteroids.
Millions of asteroids, mostly small, whirl around the solar system. It is not uncommon for the fireball of an incoming asteroid to light up the night sky and then for people find meteorites — the surviving rock fragments. But in most cases, scientists can only guess what kind of asteroid the meteorites came from.
“We now have the first samples in hand of a known asteroid, characterized in a way other asteroids are,” said Petrus M. Jenniskens, a scientist at the SETI Institute in Mountain View, Calif., who organized the search teams for the meteorites and is the lead author of the Nature paper.
Richard Kowalski first spotted the asteroid on Oct. 5 at an observatory on Mount Lemmon in Arizona. He noticed a white dot moving on his computer screen and sent the coordinates to the Minor Planet Center at the Harvard-Smithsonian Center for Astrophysics.
The next morning, Timothy B. Spahr, director of the Minor Planet Center, got to work. The asteroid, designated 2008 TC3, was passing so close that the Earth’s gravity was greatly distorting its orbit. In fact, the asteroid looked as if it was being pulled directly into Earth.
Dr. Spahr woke up a colleague, Gareth Williams, who calculates the probabilities of impacts. Based on the initial sparse data, Mr. Williams calculated 80 percent. With some more data, the probability rose to 100 percent.
From the brightness, Dr. Spahr and Mr. Williams knew that the asteroid was small — about the size of a car and 70 tons — and would not cause any damage. Notice of 2008 TC3 quickly spread. By the time the asteroid disintegrated about 23 miles over the Nubian desert of northern Sudan, 20 hours after Mr. Kowalski spotted it, both professional and amateur asteroid watchers had pointed their telescopes to it.
Even a KLM pilot alerted to the asteroid was able to spot the fireball from more than 800 miles away. The expectation was that none of 2008 TC3 survived the passage through the atmosphere. But still, Dr. Jenniskens, an expert on meteor showers, wondered.
In December, he flew to Sudan and organized a team of 45 students and staff members from the University of Khartoum to search through the desert for fragments of 2008 TC3. And they found them — shiny black fragments, about 280 of them, weighing several pounds in total. The meteorites turned out to be a strange type known as ureilites — a hodgepodge of different minerals that had been heated but not totally melted.
The observations of 2008 TC3 before impact showed that it belonged to the F-class of meteorites. Thus, for the first time, scientists has direct evidence that ureilite meteorites originate from F-class asteroids.
Link: NYTimes Article
Scientists Examine Asteroid Remains
Kenneth Chang
New York Times
25 March 2009
Scientists who for the first time tracked an asteroid on a collision course with Earth, and watched as it exploded in the atmosphere, have now picked up some of the remnants on the ground. The discovery and analysis of the meteorites, reported in Thursday’s issue of the journal Nature, give scientists solid data on the composition of meteorites that originate from what are known as F-class asteroids.
Millions of asteroids, mostly small, whirl around the solar system. It is not uncommon for the fireball of an incoming asteroid to light up the night sky and then for people find meteorites — the surviving rock fragments. But in most cases, scientists can only guess what kind of asteroid the meteorites came from.
“We now have the first samples in hand of a known asteroid, characterized in a way other asteroids are,” said Petrus M. Jenniskens, a scientist at the SETI Institute in Mountain View, Calif., who organized the search teams for the meteorites and is the lead author of the Nature paper.
Richard Kowalski first spotted the asteroid on Oct. 5 at an observatory on Mount Lemmon in Arizona. He noticed a white dot moving on his computer screen and sent the coordinates to the Minor Planet Center at the Harvard-Smithsonian Center for Astrophysics.
The next morning, Timothy B. Spahr, director of the Minor Planet Center, got to work. The asteroid, designated 2008 TC3, was passing so close that the Earth’s gravity was greatly distorting its orbit. In fact, the asteroid looked as if it was being pulled directly into Earth.
Dr. Spahr woke up a colleague, Gareth Williams, who calculates the probabilities of impacts. Based on the initial sparse data, Mr. Williams calculated 80 percent. With some more data, the probability rose to 100 percent.
From the brightness, Dr. Spahr and Mr. Williams knew that the asteroid was small — about the size of a car and 70 tons — and would not cause any damage. Notice of 2008 TC3 quickly spread. By the time the asteroid disintegrated about 23 miles over the Nubian desert of northern Sudan, 20 hours after Mr. Kowalski spotted it, both professional and amateur asteroid watchers had pointed their telescopes to it.
Even a KLM pilot alerted to the asteroid was able to spot the fireball from more than 800 miles away. The expectation was that none of 2008 TC3 survived the passage through the atmosphere. But still, Dr. Jenniskens, an expert on meteor showers, wondered.
In December, he flew to Sudan and organized a team of 45 students and staff members from the University of Khartoum to search through the desert for fragments of 2008 TC3. And they found them — shiny black fragments, about 280 of them, weighing several pounds in total. The meteorites turned out to be a strange type known as ureilites — a hodgepodge of different minerals that had been heated but not totally melted.
The observations of 2008 TC3 before impact showed that it belonged to the F-class of meteorites. Thus, for the first time, scientists has direct evidence that ureilite meteorites originate from F-class asteroids.
Link: NYTimes Article
24 March 2009
NASA Teleconference (25 March 2009, 2 p.m. EDT) To Discuss Recovered Meteorites From Sundan
NASA teleconference on 25 March 2009 to discuss 2008 TC3 and the recovery of meteorite samples in the Sudan. Remember there is another NASA online media broadcast at 7:30 PM EDT on the same day. Here is the media advisory...
NASA Sets Teleconference To Discuss Recovered Meteorites
WASHINGTON -- NASA will hold a media teleconference on Wednesday, March 25, at 2 p.m. EDT to reveal science findings from recently discovered meteorites. The meteorites originate from a small asteroid that entered Earth's atmosphere over the Nubian Desert of northern Sudan on Oct. 7, 2008. The discovery presents scientists with an unprecedented opportunity to understand these nomads of the solar system better.
The briefing participants are:
- Peter Jenniskens, meteor astronomer at NASA's Ames Research Center, Moffett Field, Calif., and the SETI Institute in Mountain View, Calif.
- Steve Chesley, scientist in NASA's Near-Earth Object Program Office at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
- Michael Zolensky, cosmic mineralogist at NASA's Johnson Space Center in Houston
- Lucy McFadden, professor of astronomy at the University of Maryland in College Park
Link: NASA Media Advisory
NASA Sets Teleconference To Discuss Recovered Meteorites
WASHINGTON -- NASA will hold a media teleconference on Wednesday, March 25, at 2 p.m. EDT to reveal science findings from recently discovered meteorites. The meteorites originate from a small asteroid that entered Earth's atmosphere over the Nubian Desert of northern Sudan on Oct. 7, 2008. The discovery presents scientists with an unprecedented opportunity to understand these nomads of the solar system better.
The briefing participants are:
- Peter Jenniskens, meteor astronomer at NASA's Ames Research Center, Moffett Field, Calif., and the SETI Institute in Mountain View, Calif.
- Steve Chesley, scientist in NASA's Near-Earth Object Program Office at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
- Michael Zolensky, cosmic mineralogist at NASA's Johnson Space Center in Houston
- Lucy McFadden, professor of astronomy at the University of Maryland in College Park
Link: NASA Media Advisory
Interesting Slashdot Poll: I expect the last human on Earth to be born ...
Slashdot asked for responses to the following statement: I expect the last human on Earth to be born ...
Results as of 7:38 PM (Eastern US Time) on 24 March 2009:
... within the next 100 years. 2297 votes / 10%
... 100-1,000 years from now. 5049 votes / 22%
... 1,000-10,000 years from now. 4735 votes / 20%
... 10,000-1,000,000 years from now. 4872 votes / 21%
... More than 1,000,000 years from now. 3071 votes / 13%
Too late, we're just waiting for the comet. 2846 votes / 12%
(22870 total votes.)
Link: Slashdot Poll Results
Results as of 7:38 PM (Eastern US Time) on 24 March 2009:
... within the next 100 years. 2297 votes / 10%
... 100-1,000 years from now. 5049 votes / 22%
... 1,000-10,000 years from now. 4735 votes / 20%
... 10,000-1,000,000 years from now. 4872 votes / 21%
... More than 1,000,000 years from now. 3071 votes / 13%
Too late, we're just waiting for the comet. 2846 votes / 12%
(22870 total votes.)
Link: Slashdot Poll Results
Chat With NASA's Asteroid Trackers: March 25 at 4:30 p.m. PDT (7:30 p.m. EDT and 23:30 UTC)
From the NASA News announcement...
A live videocast and chat from NASA's Jet Propulsion Laboratory, Pasadena, Calif., offers a unique opportunity for viewers to ask questions of scientists with NASA's Near-Earth Object Program Office about how NASA discovers and tracks asteroids.
The live event will air on the "NASAJPL" channel available on Ustream TV at: http://www.ustream.tv/channel/nasajpl on March 25 at 4:30 p.m. PDT (7:30 p.m. EDT and 23:30 UTC).
NASA detects and tracks asteroids and comets passing close to Earth. The Near-Earth Object Observation Program, commonly called "Spaceguard," discovers, characterizes and computes trajectories for these objects to determine if any could be potentially hazardous to our planet.
Participants include:
-- Don Yeomans, manager, NASA's Near-Earth Object Office at JPL
-- Steve Chesley, scientist, NASA's Near-Earth Object Office at JPL
-- Paul Chodas, scientist, NASA's Near-Earth Object Office at JPL
Link: NASA News Announcement - Live Chat with NASA's Asteroid Trackers
Link: NASA NEO JPL Page Annoucement
Link: NASA UStream Link
A live videocast and chat from NASA's Jet Propulsion Laboratory, Pasadena, Calif., offers a unique opportunity for viewers to ask questions of scientists with NASA's Near-Earth Object Program Office about how NASA discovers and tracks asteroids.
The live event will air on the "NASAJPL" channel available on Ustream TV at: http://www.ustream.tv/channel/nasajpl on March 25 at 4:30 p.m. PDT (7:30 p.m. EDT and 23:30 UTC).
NASA detects and tracks asteroids and comets passing close to Earth. The Near-Earth Object Observation Program, commonly called "Spaceguard," discovers, characterizes and computes trajectories for these objects to determine if any could be potentially hazardous to our planet.
Participants include:
-- Don Yeomans, manager, NASA's Near-Earth Object Office at JPL
-- Steve Chesley, scientist, NASA's Near-Earth Object Office at JPL
-- Paul Chodas, scientist, NASA's Near-Earth Object Office at JPL
Link: NASA News Announcement - Live Chat with NASA's Asteroid Trackers
Link: NASA NEO JPL Page Annoucement
Link: NASA UStream Link
21 March 2009
Asteroid 2009 FH: Earth Flyby on 18 March 2009
Late on posting this but here it is nonetheless. From JPL...
A small asteroid will fly past Earth early tomorrow morning (Wed., March 18). The asteroid, 2009 FH, is about 50 feet (15 meters) wide. Its closest approach to Earth will occur at 5:17 a.m. PDT (8:17 a.m. EDT, 12:17 UTC) at an altitude of about 49,000 miles (79,000 kilometers).
"This asteroid flyby will be a good viewing opportunity for both professional and amateur astronomers," said Don Yeomans of the Near-Earth Object Office at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "The asteroid poses no risk of impact to Earth now or for the foreseeable future."
NASA detects and tracks asteroids and comets passing close to Earth. The Near Earth Object Observation Program, commonly called "Spaceguard," plots the orbits of these objects to determine if any could be potentially hazardous to our planet.
Link: JPL NEO Site News Article
Link: JPL Orbit Diagram for 2009 FH
Position Open at the Minor Planet Center (MPC)
Here is an announcement of a position available at the Minor Planet Center (MPC).
Opening date: March 10, 2009
Closing date: Open Until Filled
TITLE: IT Specialist (Applications Software), IS-2210, Grade 11; $61,425 to $79,847/yr
TYPE OF POSITION: Trust Fund (non-federal) Indefinite
DIVISION: - Solar Stellar and Planetary Sciences Division
LOCATION: Cambridge, Massachusetts
AREA OF CONSIDERATION: All qualified candidates
This is the position of Information Technology Specialist (Applications Software), Minor Planet Center (MPC), Smithsonian Astrophysical Observatory. The employee has applications programming responsibilities on workstation based processing systems for the MPC in one or more of the following areas: data receipt and quality control, data archiving and retrieval, data reduction, data analysis and data distribution. The employee reports to the Director of the MPC, and works closely with the members of his/her team and other designated MPC scientists and programmers participating in the project.
Link: Minor Planet Center (MPC) Position Listing
Opening date: March 10, 2009
Closing date: Open Until Filled
TITLE: IT Specialist (Applications Software), IS-2210, Grade 11; $61,425 to $79,847/yr
TYPE OF POSITION: Trust Fund (non-federal) Indefinite
DIVISION: - Solar Stellar and Planetary Sciences Division
LOCATION: Cambridge, Massachusetts
AREA OF CONSIDERATION: All qualified candidates
This is the position of Information Technology Specialist (Applications Software), Minor Planet Center (MPC), Smithsonian Astrophysical Observatory. The employee has applications programming responsibilities on workstation based processing systems for the MPC in one or more of the following areas: data receipt and quality control, data archiving and retrieval, data reduction, data analysis and data distribution. The employee reports to the Director of the MPC, and works closely with the members of his/her team and other designated MPC scientists and programmers participating in the project.
Link: Minor Planet Center (MPC) Position Listing
Interesting Facebook Group: "We should leave now"
An interesting group on Facebook, "We should leave now." Here is their description:
"Don't keep all your eggs in one basket"
Throughout the ages of this earth, earth's been hit by devestating impacts from stellar objects (eg, asteroids, comets, etc...) setting life back on earth, killing thousands of individual creatures and causing mass extinctions.
it's only a matter of time until it happens again...
So, just as a precaution, we should fund people like Burt Rutan, who created spaceship one, the first commercially built space craft to enter space. only when we have self sufficient colonies on more than one planet will the human race be safe... and even then...
and this isn't one of those things that'll never happen: in 1994, comet shoemaker-levy colided with jupiter.
Link: Facebook Group "We should leave now"
"Don't keep all your eggs in one basket"
Throughout the ages of this earth, earth's been hit by devestating impacts from stellar objects (eg, asteroids, comets, etc...) setting life back on earth, killing thousands of individual creatures and causing mass extinctions.
it's only a matter of time until it happens again...
So, just as a precaution, we should fund people like Burt Rutan, who created spaceship one, the first commercially built space craft to enter space. only when we have self sufficient colonies on more than one planet will the human race be safe... and even then...
and this isn't one of those things that'll never happen: in 1994, comet shoemaker-levy colided with jupiter.
Link: Facebook Group "We should leave now"
NASA Grant Opportunity: ROSES 2009: Near Earth Object Observations
There is a recent NASA research announcement funding solicitation about NEOs. A summary of the solicitation follows:
Science Mission Directorate
NASA Research Announcement (NRA)
Near Earth Object Observations
Solicitation: NNH09ZDA001N-NEOO
Release: Feb 13, 2009
NEOO09 NOIs Due: Apr 23, 2009
NEOO09 Proposals Due: Jun 12, 2009
Near Earth Objects (NEOs) are defined as asteroids or comet nuclei whose perihelia are less than 1.3 AU. NASA is committed to discovering all NEOs with diameters greater than or equal to ~1 km and to characterizing that population through determination of their orbital elements, with the goal of detecting 90 percent of this population as soon as possible. In support of NASA’s commitment and goal, this program supports NEO investigations whose primary objective is to inventory the population of NEOs with diameters greater than or equal to 1 km. In addition to this goal, the U.S. Congress has expressed an interest for NASA to extend the survey down to objects as small as 140 meters which might pose a hazard to impacting the Earth. Therefore, investigations that provide capability to detect the subset of NEOs in this category, Potentially Hazardous Objects (PHOs) down to 140 meters in size, will receive additional consideration.
In order to help achieve this inventory of NEOs, NASA seeks investigations that promise a sustained, productive search for NEOs and/or obtain follow-up observations of sufficient astrometric precision to allow the accurate prediction of the trajectories of discovered objects. NASA will also consider within this program proposals that characterize a representative sample of these objects by measuring their sizes, shapes, and compositions.
Link: NASA NSPIES NEO Grant (PDF)
Link: NASA NRA Solicitation: NNH09ZDA001N-NEOO Main NSPIRES Page
Link: Grant.gov listing
Science Mission Directorate
NASA Research Announcement (NRA)
Near Earth Object Observations
Solicitation: NNH09ZDA001N-NEOO
Release: Feb 13, 2009
NEOO09 NOIs Due: Apr 23, 2009
NEOO09 Proposals Due: Jun 12, 2009
Near Earth Objects (NEOs) are defined as asteroids or comet nuclei whose perihelia are less than 1.3 AU. NASA is committed to discovering all NEOs with diameters greater than or equal to ~1 km and to characterizing that population through determination of their orbital elements, with the goal of detecting 90 percent of this population as soon as possible. In support of NASA’s commitment and goal, this program supports NEO investigations whose primary objective is to inventory the population of NEOs with diameters greater than or equal to 1 km. In addition to this goal, the U.S. Congress has expressed an interest for NASA to extend the survey down to objects as small as 140 meters which might pose a hazard to impacting the Earth. Therefore, investigations that provide capability to detect the subset of NEOs in this category, Potentially Hazardous Objects (PHOs) down to 140 meters in size, will receive additional consideration.
In order to help achieve this inventory of NEOs, NASA seeks investigations that promise a sustained, productive search for NEOs and/or obtain follow-up observations of sufficient astrometric precision to allow the accurate prediction of the trajectories of discovered objects. NASA will also consider within this program proposals that characterize a representative sample of these objects by measuring their sizes, shapes, and compositions.
Link: NASA NSPIES NEO Grant (PDF)
Link: NASA NRA Solicitation: NNH09ZDA001N-NEOO Main NSPIRES Page
Link: Grant.gov listing
16 March 2009
Paper on Impact on the Moon (Published in Icarus)
"Did a large impact reorient the Moon?"
Mark A. Wieczore
Mathieu Le Feuvrea
Icarus
Volume 200, Issue 2, April 2009, Pages 358-366
Abstract:
The Moon is currently locked in a spin–orbit resonance of synchronous rotation, of which one consequence is that more impacts should occur near the Moon's apex of motion (0° N, 90° W) than near its antapex of motion (0° N, 90° E). Several of the largest lunar impact basins could have temporarily unlocked the Moon from synchronous rotation, and after the re-establishment of this state the Moon would have been left in either its initial orientation, or one that was rotated 180° about its spin axis. We show that there is less than a 2% probability that the oldest lunar impact basins are randomly distributed across the lunar surface. Furthermore, these basins are preferentially located near the Moon's antapex of motion, and this configuration has less than a 0.3% probability of occurring by chance. We postulate that the current “near side” of the Moon was in fact its “far side” when the oldest basins formed. One basin with the required size and temporal characteristics to account for a 180° reorientation is the Smythii basin.
Link: Abstract from Icarus
Mark A. Wieczore
Mathieu Le Feuvrea
Icarus
Volume 200, Issue 2, April 2009, Pages 358-366
Abstract:
The Moon is currently locked in a spin–orbit resonance of synchronous rotation, of which one consequence is that more impacts should occur near the Moon's apex of motion (0° N, 90° W) than near its antapex of motion (0° N, 90° E). Several of the largest lunar impact basins could have temporarily unlocked the Moon from synchronous rotation, and after the re-establishment of this state the Moon would have been left in either its initial orientation, or one that was rotated 180° about its spin axis. We show that there is less than a 2% probability that the oldest lunar impact basins are randomly distributed across the lunar surface. Furthermore, these basins are preferentially located near the Moon's antapex of motion, and this configuration has less than a 0.3% probability of occurring by chance. We postulate that the current “near side” of the Moon was in fact its “far side” when the oldest basins formed. One basin with the required size and temporal characteristics to account for a 180° reorientation is the Smythii basin.
Link: Abstract from Icarus
Abstracts for the IAA 2009 Planetary Defense Conference Up
Abstracts for the upcoming IAA 2009 Planetary Defense Conference are now available.
Link: IAA 2009 Planetary Defense Conference Agenda (with PDF abstracts)
Link: Zip archive of all abstracts for IAA 2009 Planetary Defense Conference
Link: IAA 2009 Planetary Defense Conference Agenda (with PDF abstracts)
Link: Zip archive of all abstracts for IAA 2009 Planetary Defense Conference
12 March 2009
NEO News (03/12/09) UN Report on NEO Threat Mitigation
From Dave Morrison.
NEO News (03/12/09) UN Report on NEO Threat Mitigation
The Association of Space Explorers (made up of astronauts and cosmonauts) has been working with a distinguished international panel of experts to develop the foundations for a UN-based agreement on asteroid threat mitigation. This panel (organized and chaired by Rusty Schweickart) completed in late 2008 a recommended decision program to aid the international community in organizing a coordinated response to asteroid impact threats. These recommendations have been disseminated in the past three months within the UN. Rusty reports that the report has been favorably received, follow-on internal documents are in editing, and the work is incorporated in the approved 3-year work-plan for the UN committee on peaceful uses of outer space. Below is the summary section of that report and a link to a pdf of the entire document.
David Morrison
=================================
DECISION PROGRAM ON ASTEROID THREAT MITIGATION
Russell L. Schweickart
Chairman, Committee on Near-Earth Objects
Association of Space Explorers
Sonoma, California
ABSTRACT
The Association of Space Explorers Committee on Near-Earth Objects (NEOs) and its Panel on Asteroid Threat Mitigation have prepared a decision program to aid the international community in organizing a coordinated response to asteroid impact threats. The program is described in the ASE's report, Asteroid Threats: A Call for Global Response, which will be considered by the United Nations Committee on the Peaceful Uses of Outer Space in its 2009 sessions. The findings and recommendations of this report are presented here as well as some of the major implications of the complex decision-making involved in developing a coordinated international response to the challenge of protecting the Earth from NEO impacts.
BACKGROUND
In its 2009 sessions the United Nations Committee on the Peaceful Uses of Outer Space (UN-COPUOS) will be presented with a decision program on asteroid threat mitigation developed over a two year period by the Association of Space Explorersi (ASE), the international organization of astronauts and cosmonauts from 34 nations. The program was developed by the ASE Committee on Near-Earth Objects (ASE-NEO) and its Panel on Asteroid Threat Mitigation, a distinguished international group of experts in science, law, diplomacy, and disaster management.
The ASE effort was initiated during its 2005 Congress when the members took note of the series of international disasters which had occurred that year (especially the Indian Ocean tsunami, hurricanes
Katrina and Rita, and the Pakistani earthquake) and the recognition of the critical role of preparation and warning in saving lives. Being also aware of the devastation caused by NEO impacts with Earth, the accelerating discovery rate of NEOs and the emerging technical capability (with adequate early warning) to divert such NEOs from impacting Earth, the Association realized the need for systematic preparation for this eventuality by the international community.
Recognizing the significance of this need the ASE issued an open letter to world institutions and leaders calling on them to "acknowledge this challenge and accept the responsibility for prevention of these most devastating of all natural disasters." To support such efforts ASE created an ASE-NEO committee and charged it with supporting "national and international responses by providing relevant information, organizing meetings or workshops, and providing expert witnesses." In 2006 the ASE-NEO committee, utilizing the ASE's Observer status in UN/COPUOS, assumed membership on Action Team-14 (NEO) of COPUOS and initiated an effort to develop a decision program on asteroid deflection for consideration by the international community. To support this effort ASE-NEO formed its international Panel on Asteroid Threat Mitigation and initiated a series of four workshops to develop this program.
The result of this effort is the report, Asteroid Threats: A Call for Global Response, currently in process by Action Team-14 for introduction to COPUOS in its 2009 sessions.
SUMMARY FINDINGS
Our highly interconnected society is vulnerable to the destructive power of impact events ranging from the 1908 Tunguska event in which the impact of an estimated 45 meter diameter object destroyed 2000 square kilometers of Siberian forest to the 12 kilometer diameter object responsible for the Chicxulub impact 65 million years ago which is thought to have caused the extinction of the dinosaurs and 70% of all species alive at the time. Such cosmic collisions occur infrequently juxtaposed with a human lifetime, and yet when they do happen they dwarf other natural disasters more common in human experience.
Yet surprisingly in the instance of this most devastating of natural disasters we are far from helpless. With our telescopic and spaceflight capabilities we can detect and predict potential impacts, and with adequate early warning we can deploy space systems capable of altering the orbit of threatening NEOs sufficient to cause them to pass harmlessly by the Earth thereby avoiding an impact.
In the event of a discovery where insufficient time is available to successfully divert a threatening NEO we will nevertheless, if prepared, be able to mitigate the effects of an impact by evacuation and other disaster preparedness measures. What is needed to match the technical capability for responding to the NEO impact challenge is an in-place international system of preparation, planning and timely decision-making. The need for attention to this issue now by the international community is driven by the rapid expansion of the number of NEOs which will be discovered and tracked in the next 10-15 years, and the inherent geographic variability associated with impact prediction and deflection operations.
New telescopic resources coming into service within the next decade will dramatically increase the number of NEOs discovered and tracked. The US Congress has charged NASA with discovering and tracking 90% of all NEOs larger than 140 meters in diameter by 2020. While meeting this goal poses a considerable challenge, it is clear that with new telescopes coming online (e.g. Pan-STARRS and LSST) this goal will be approached in the 2020-2025 time-frame. In the process of achieving the 140 meter goal many smaller but still dangerous NEOs will be discovered with the number of such objects likely to exceed 300,000.
Based on current empirical experience the number of potentially damaging NEOs with a non-zero probability of impact within the next 100 years is likely to exceed 10,000 by this time. Of these NEOs with at least a small probability of impact over the next 100 years many are likely to appear threatening enough to necessitate a decision of whether action should be taken to prevent an impact. The need for international coordination in making such a decision is determined by the natural uncertainty regarding which specific populations are at risk in predicting an impact and the inherent shifting of risk in the process of deflection.
All measurements have an associated uncertainty and in the instance of NEO observations these measurement uncertainties, projected forward in time, manifest as a risk corridor across the face of the Earth within which, if it impacts, the NEO will hit. While in the end an impact would occur at a specific point, at the time a decision must be made to deflect a threatening object the impact zone will extend for some distance along the risk corridor and, in fact, in many instances may well extend beyond the Earth's limbs for many Earth diameters in both directions. Hence, at the time a deflection decision must be made (to provide adequate time to conduct the operation and for the deflection to take effect) it is likely that the people of many nations will be at risk. Furthermore in the process of deflection per se, there will be a temporary shifting of risk between populations as the NEO impact point is itself shifted from a point on the Earth's surface to a safe distance along the risk corridor either ahead of or behind the Earth.
Because NEO impacts can occur anywhere on our planet and affect the entire international community, a collaborative, global response is required. Furthermore it is highly desirable that a decision process, with agreed criteria, policies and procedures be established prior to the development of a specific threat in order to assure that minimization of risk to life and property prevail over competing national self interests.
PRIMARY RECOMMENDATIONS
A global, coordinated response by the United Nations to the NEO impact hazard should ensure that three logical, necessary functions are performed:
Information Gathering, Analysis, and Warning. An Information, Analysis, and Warning Network should be established. This Network would operate a global system of ground- and/or space-based telescopes to detect and track potentially hazardous NEOs. The Network, using existing or new research institutions, should analyze NEO orbits to identify potential impacts. The Network should establish criteria for issuing NEO impact warnings.
Mission Planning and Operations. A Mission Planning and Operations "Group," drawing on the expertise of the space-faring nations, should be established and mandated to outline the most likely options for NEO deflection missions. This group should assess the current, global capacity to deflect a hazardous NEO by gathering necessary NEO information, identifying required technologies, and surveying the NEO-related capabilities of interested space agencies. In response to a specific warning, the group should use these mission plans to prepare for a deflection campaign to prevent the threatened impact.
NEO Threat Oversight and Recommendation for Action. The United Nations should exercise oversight of the above functions through an intergovernmental Mission Authorization and Oversight "Group." This group would develop the policies and guidelines that represent the international will to respond to the global impact hazard. The Mission Authorization and Oversight Group should establish impact risk thresholds and criteria to determine when to execute a NEO deflection campaign. The Mission Authorization and Oversight Group would submit recommendations to the Security Council for appropriate action.
Continued; see pdf at http://www.space-explorers.org/committees/NEO/docs/ATACGR.pdf.
Association of Space Explorers International Panel on Asteroid Threat Mitigation
Russell Schweickart, Chair*
Adigun Ade Abiodun
Vallampadugai Arunachalam
Sergei Avdeev*
Roger-Maurice Bonnet
Sergio Camacho-Lara
Franklin Chang-Diaz*
James George
Tomifumi Godai
Chris Hadfield*
Peter Jankowitsch
Thomas Jones*
Sergey Kapitza
Paul Kovacs
Walther Lichem
Edward Lu*
Gordon McBean
Dorin Prunariu*
Martin Rees
Karlene Roberts
Viktor Savinykh*
Michael Simpson
Crispin Tickell
Frans von der Dunk
Richard Tremayne-Smith
James Zimmerman
*Association of Space Explorers Near-Earth Object Committee
--
+++++++++++++++++++++++++++++++++++++++++++
NEO News (now in its fourteenth year of distribution) is an informal compilation of news and opinion dealing with Near Earth Objects (NEOs) and their impacts. These opinions are the responsibility of the individual authors and do not represent the positions of NASA, Ames Research Center, the International Astronomical Union, or any other organization. To subscribe (or unsubscribe) contact dmorrison@arc.nasa.gov. For additional information, please see the website http://impact.arc.nasa.gov. If anyone wishes to copy or redistribute original material from these notes, fully or in part, please include this disclaimer.
NEO News (03/12/09) UN Report on NEO Threat Mitigation
The Association of Space Explorers (made up of astronauts and cosmonauts) has been working with a distinguished international panel of experts to develop the foundations for a UN-based agreement on asteroid threat mitigation. This panel (organized and chaired by Rusty Schweickart) completed in late 2008 a recommended decision program to aid the international community in organizing a coordinated response to asteroid impact threats. These recommendations have been disseminated in the past three months within the UN. Rusty reports that the report has been favorably received, follow-on internal documents are in editing, and the work is incorporated in the approved 3-year work-plan for the UN committee on peaceful uses of outer space. Below is the summary section of that report and a link to a pdf of the entire document.
David Morrison
=================================
DECISION PROGRAM ON ASTEROID THREAT MITIGATION
Russell L. Schweickart
Chairman, Committee on Near-Earth Objects
Association of Space Explorers
Sonoma, California
ABSTRACT
The Association of Space Explorers Committee on Near-Earth Objects (NEOs) and its Panel on Asteroid Threat Mitigation have prepared a decision program to aid the international community in organizing a coordinated response to asteroid impact threats. The program is described in the ASE's report, Asteroid Threats: A Call for Global Response, which will be considered by the United Nations Committee on the Peaceful Uses of Outer Space in its 2009 sessions. The findings and recommendations of this report are presented here as well as some of the major implications of the complex decision-making involved in developing a coordinated international response to the challenge of protecting the Earth from NEO impacts.
BACKGROUND
In its 2009 sessions the United Nations Committee on the Peaceful Uses of Outer Space (UN-COPUOS) will be presented with a decision program on asteroid threat mitigation developed over a two year period by the Association of Space Explorersi (ASE), the international organization of astronauts and cosmonauts from 34 nations. The program was developed by the ASE Committee on Near-Earth Objects (ASE-NEO) and its Panel on Asteroid Threat Mitigation, a distinguished international group of experts in science, law, diplomacy, and disaster management.
The ASE effort was initiated during its 2005 Congress when the members took note of the series of international disasters which had occurred that year (especially the Indian Ocean tsunami, hurricanes
Katrina and Rita, and the Pakistani earthquake) and the recognition of the critical role of preparation and warning in saving lives. Being also aware of the devastation caused by NEO impacts with Earth, the accelerating discovery rate of NEOs and the emerging technical capability (with adequate early warning) to divert such NEOs from impacting Earth, the Association realized the need for systematic preparation for this eventuality by the international community.
Recognizing the significance of this need the ASE issued an open letter to world institutions and leaders calling on them to "acknowledge this challenge and accept the responsibility for prevention of these most devastating of all natural disasters." To support such efforts ASE created an ASE-NEO committee and charged it with supporting "national and international responses by providing relevant information, organizing meetings or workshops, and providing expert witnesses." In 2006 the ASE-NEO committee, utilizing the ASE's Observer status in UN/COPUOS, assumed membership on Action Team-14 (NEO) of COPUOS and initiated an effort to develop a decision program on asteroid deflection for consideration by the international community. To support this effort ASE-NEO formed its international Panel on Asteroid Threat Mitigation and initiated a series of four workshops to develop this program.
The result of this effort is the report, Asteroid Threats: A Call for Global Response, currently in process by Action Team-14 for introduction to COPUOS in its 2009 sessions.
SUMMARY FINDINGS
Our highly interconnected society is vulnerable to the destructive power of impact events ranging from the 1908 Tunguska event in which the impact of an estimated 45 meter diameter object destroyed 2000 square kilometers of Siberian forest to the 12 kilometer diameter object responsible for the Chicxulub impact 65 million years ago which is thought to have caused the extinction of the dinosaurs and 70% of all species alive at the time. Such cosmic collisions occur infrequently juxtaposed with a human lifetime, and yet when they do happen they dwarf other natural disasters more common in human experience.
Yet surprisingly in the instance of this most devastating of natural disasters we are far from helpless. With our telescopic and spaceflight capabilities we can detect and predict potential impacts, and with adequate early warning we can deploy space systems capable of altering the orbit of threatening NEOs sufficient to cause them to pass harmlessly by the Earth thereby avoiding an impact.
In the event of a discovery where insufficient time is available to successfully divert a threatening NEO we will nevertheless, if prepared, be able to mitigate the effects of an impact by evacuation and other disaster preparedness measures. What is needed to match the technical capability for responding to the NEO impact challenge is an in-place international system of preparation, planning and timely decision-making. The need for attention to this issue now by the international community is driven by the rapid expansion of the number of NEOs which will be discovered and tracked in the next 10-15 years, and the inherent geographic variability associated with impact prediction and deflection operations.
New telescopic resources coming into service within the next decade will dramatically increase the number of NEOs discovered and tracked. The US Congress has charged NASA with discovering and tracking 90% of all NEOs larger than 140 meters in diameter by 2020. While meeting this goal poses a considerable challenge, it is clear that with new telescopes coming online (e.g. Pan-STARRS and LSST) this goal will be approached in the 2020-2025 time-frame. In the process of achieving the 140 meter goal many smaller but still dangerous NEOs will be discovered with the number of such objects likely to exceed 300,000.
Based on current empirical experience the number of potentially damaging NEOs with a non-zero probability of impact within the next 100 years is likely to exceed 10,000 by this time. Of these NEOs with at least a small probability of impact over the next 100 years many are likely to appear threatening enough to necessitate a decision of whether action should be taken to prevent an impact. The need for international coordination in making such a decision is determined by the natural uncertainty regarding which specific populations are at risk in predicting an impact and the inherent shifting of risk in the process of deflection.
All measurements have an associated uncertainty and in the instance of NEO observations these measurement uncertainties, projected forward in time, manifest as a risk corridor across the face of the Earth within which, if it impacts, the NEO will hit. While in the end an impact would occur at a specific point, at the time a decision must be made to deflect a threatening object the impact zone will extend for some distance along the risk corridor and, in fact, in many instances may well extend beyond the Earth's limbs for many Earth diameters in both directions. Hence, at the time a deflection decision must be made (to provide adequate time to conduct the operation and for the deflection to take effect) it is likely that the people of many nations will be at risk. Furthermore in the process of deflection per se, there will be a temporary shifting of risk between populations as the NEO impact point is itself shifted from a point on the Earth's surface to a safe distance along the risk corridor either ahead of or behind the Earth.
Because NEO impacts can occur anywhere on our planet and affect the entire international community, a collaborative, global response is required. Furthermore it is highly desirable that a decision process, with agreed criteria, policies and procedures be established prior to the development of a specific threat in order to assure that minimization of risk to life and property prevail over competing national self interests.
PRIMARY RECOMMENDATIONS
A global, coordinated response by the United Nations to the NEO impact hazard should ensure that three logical, necessary functions are performed:
Information Gathering, Analysis, and Warning. An Information, Analysis, and Warning Network should be established. This Network would operate a global system of ground- and/or space-based telescopes to detect and track potentially hazardous NEOs. The Network, using existing or new research institutions, should analyze NEO orbits to identify potential impacts. The Network should establish criteria for issuing NEO impact warnings.
Mission Planning and Operations. A Mission Planning and Operations "Group," drawing on the expertise of the space-faring nations, should be established and mandated to outline the most likely options for NEO deflection missions. This group should assess the current, global capacity to deflect a hazardous NEO by gathering necessary NEO information, identifying required technologies, and surveying the NEO-related capabilities of interested space agencies. In response to a specific warning, the group should use these mission plans to prepare for a deflection campaign to prevent the threatened impact.
NEO Threat Oversight and Recommendation for Action. The United Nations should exercise oversight of the above functions through an intergovernmental Mission Authorization and Oversight "Group." This group would develop the policies and guidelines that represent the international will to respond to the global impact hazard. The Mission Authorization and Oversight Group should establish impact risk thresholds and criteria to determine when to execute a NEO deflection campaign. The Mission Authorization and Oversight Group would submit recommendations to the Security Council for appropriate action.
Continued; see pdf at http://www.space-explorers.org/committees/NEO/docs/ATACGR.pdf.
Association of Space Explorers International Panel on Asteroid Threat Mitigation
Russell Schweickart, Chair*
Adigun Ade Abiodun
Vallampadugai Arunachalam
Sergei Avdeev*
Roger-Maurice Bonnet
Sergio Camacho-Lara
Franklin Chang-Diaz*
James George
Tomifumi Godai
Chris Hadfield*
Peter Jankowitsch
Thomas Jones*
Sergey Kapitza
Paul Kovacs
Walther Lichem
Edward Lu*
Gordon McBean
Dorin Prunariu*
Martin Rees
Karlene Roberts
Viktor Savinykh*
Michael Simpson
Crispin Tickell
Frans von der Dunk
Richard Tremayne-Smith
James Zimmerman
*Association of Space Explorers Near-Earth Object Committee
--
+++++++++++++++++++++++++++++++++++++++++++
NEO News (now in its fourteenth year of distribution) is an informal compilation of news and opinion dealing with Near Earth Objects (NEOs) and their impacts. These opinions are the responsibility of the individual authors and do not represent the positions of NASA, Ames Research Center, the International Astronomical Union, or any other organization. To subscribe (or unsubscribe) contact dmorrison@arc.nasa.gov. For additional information, please see the website http://impact.arc.nasa.gov. If anyone wishes to copy or redistribute original material from these notes, fully or in part, please include this disclaimer.
11 March 2009
Paper: Long term impact risk for (101955) 1999 RQ36
Arecibo Observatory radar image of 1999 RQ36, courtesy Arecibo Observatory and JPL.
"Long term impact risk for (101955) 1999 RQ36"
Andrea Milani1, Steven R. Chesley, Maria Eugenia Sansaturio, Fabrizio Bernardi, Giovanni B. Valsecchi, Oscar Arratia
20 January 2009
Abstract:
The potentially hazardous asteroid (101955) 1999 RQ36 has the possibility of collision with the Earth in the latter half of the 22nd century, well beyond the traditional 100-year time horizon for routine impact monitoring. The probabilities accumulate to a total impact probability of approximately 10−3, with a pair of closely related routes to impact in 2182 comprising more than half of the total. The analysis of impact possibilities so far in the future is strongly dependent on the action of the Yarkovsky effect, which raises new challenges in the careful assessment of longer term impact hazards. Even for asteroids with very precisely determined orbits, a future close approach to Earth can scatter the possible trajectories to the point that the problem becomes like that of a newly discovered asteroid with a weakly determined orbit. If the scattering takes place late enough so that the target plane uncertainty is dominated by Yarkovsky accelerations then the thermal properties of the asteroid, which are typically unknown, play a major role in the impact assessment. In contrast, if the strong planetary interaction takes place sooner, while the Yarkovsky dispersion is still relatively small compared to that derived from the measurements, then precise modeling of the nongravitational acceleration may be unnecessary.
Link: Paper (PDF)
Journal Article: Rapid Solar Sail Rendezvous Missions to Asteroid 99942 Apophis
"Rapid Solar Sail Rendezvous Missions to Asteroid 99942 Apophis"
Giovanni Mengali and Alessandro A. Quarta
JOURNAL OF SPACECRAFT AND ROCKETS
Vol. 46, No. 1, January–February 2009
Abstract:
Different concepts for eliminating the threat of collision with a near-Earth object have been suggested in recent years. Most of them require that a probe is inserted in orbit around the object to obtain accurate physical and orbital data. Asteroid 99942 Apophis is a member of the Aten group of asteroids, having orbital periods shorter than 1 year. Such an asteroid is used here as a practical example to investigate the characteristics of new mission concepts and as a candidate for a potential space agency project aimed to tag an asteroid either for scientific purposes or for a deflection mission decision. The purpose of this paper is to investigate the potentialities offered by a solar-sail-based rendezvous mission toward Apophis. In particular, rapid transfer trajectories are studied, that is, missions whose transfer times are less than one terrestrial year. We show that a realistic near-term mission option, with a transfer time of about 300 days, requires a solar sail with a characteristic acceleration of 0:5 mm=s2. Asquare solar sail with a side of about 90mis needed for a payload of 50 kg, whereas a greater sail with a side of 160mis called for with a payload of 150 kg. The solar sail performance is compared to that achievable with conventional propulsion
Link: AIAA Paper (1st Page)
Link: AIAA Paper Reference
Giovanni Mengali and Alessandro A. Quarta
JOURNAL OF SPACECRAFT AND ROCKETS
Vol. 46, No. 1, January–February 2009
Abstract:
Different concepts for eliminating the threat of collision with a near-Earth object have been suggested in recent years. Most of them require that a probe is inserted in orbit around the object to obtain accurate physical and orbital data. Asteroid 99942 Apophis is a member of the Aten group of asteroids, having orbital periods shorter than 1 year. Such an asteroid is used here as a practical example to investigate the characteristics of new mission concepts and as a candidate for a potential space agency project aimed to tag an asteroid either for scientific purposes or for a deflection mission decision. The purpose of this paper is to investigate the potentialities offered by a solar-sail-based rendezvous mission toward Apophis. In particular, rapid transfer trajectories are studied, that is, missions whose transfer times are less than one terrestrial year. We show that a realistic near-term mission option, with a transfer time of about 300 days, requires a solar sail with a characteristic acceleration of 0:5 mm=s2. Asquare solar sail with a side of about 90mis needed for a payload of 50 kg, whereas a greater sail with a side of 160mis called for with a payload of 150 kg. The solar sail performance is compared to that achievable with conventional propulsion
Link: AIAA Paper (1st Page)
Link: AIAA Paper Reference
10 March 2009
NEO News (03/10/09) Update on DD45 & TN166
From Dave Morrison.
NEO News (03/10/09) Update on DD45 & TN166
2009DD45 SIZE MEASURED
As noted in NEO News of (03/07/09), the main press speculation about the close pass by NEA 2009DD45 concerned how much damage it would have caused had it hit the Earth. The range of diameters under consideration was from about 20m to 40m. These were estimates based only on the observed brightness. Rick Binzel and colleagues observed DD45 in the infrared from Mauna Kea and reported as follows to the Central Bureau for Astronomical Telegrams. R. P. Binzel, M. Birlan, and F. E. DeMeo, Paris Observatory, made 0.8- to 2.5-micron spectroscopic measurements on Mar. 2.6 UT using the NASA Infrared Telescope Facility 3-m reflector on Mauna Kea. Absorption bands revealed at 1 and 2 microns show the characteristics of the S-type class of asteroids. Using the average albedo value of 0.36 for small NEAs in this class and based on its observed brightness, the diameter is estimated to be 19 ± 4 m. This is near the lower size limit and, together with the stony composition, suggests that this object would likely have disintegrated too high to do any ground damage. Knowing the size also allows us to revise the estimate of how often a NEA of this size passes this close to Earth, to roughly once per year.
David Morrison
==========================
2008TN166 -- NOT
We reported on 03/07 that asteroid 2008TN166 appeared to be the brightest (and presumably largest) new NEA discovered since 2001. Tim Spahr, the Director of the Minor Planet Center, reports that this was an MPC misidentification. Observations of three routine Main Belt Asteroids were incorrectly linked. There is no NEA and no orbit.
--
+++++++++++++++++++++++++++++++++++++++++++
NEO News (now in its fourteenth year of distribution) is an informal compilation of news and opinion dealing with Near Earth Objects (NEOs) and their impacts. These opinions are the responsibility of the individual authors and do not represent the positions of NASA, Ames Research Center, the International Astronomical Union, or any other organization. To subscribe (or unsubscribe) contact dmorrison@arc.nasa.gov. For additional information, please see the website http://impact.arc.nasa.gov. If anyone wishes to copy or redistribute original material from these notes, fully or in part, please include this disclaimer.
NEO News (03/10/09) Update on DD45 & TN166
2009DD45 SIZE MEASURED
As noted in NEO News of (03/07/09), the main press speculation about the close pass by NEA 2009DD45 concerned how much damage it would have caused had it hit the Earth. The range of diameters under consideration was from about 20m to 40m. These were estimates based only on the observed brightness. Rick Binzel and colleagues observed DD45 in the infrared from Mauna Kea and reported as follows to the Central Bureau for Astronomical Telegrams. R. P. Binzel, M. Birlan, and F. E. DeMeo, Paris Observatory, made 0.8- to 2.5-micron spectroscopic measurements on Mar. 2.6 UT using the NASA Infrared Telescope Facility 3-m reflector on Mauna Kea. Absorption bands revealed at 1 and 2 microns show the characteristics of the S-type class of asteroids. Using the average albedo value of 0.36 for small NEAs in this class and based on its observed brightness, the diameter is estimated to be 19 ± 4 m. This is near the lower size limit and, together with the stony composition, suggests that this object would likely have disintegrated too high to do any ground damage. Knowing the size also allows us to revise the estimate of how often a NEA of this size passes this close to Earth, to roughly once per year.
David Morrison
==========================
2008TN166 -- NOT
We reported on 03/07 that asteroid 2008TN166 appeared to be the brightest (and presumably largest) new NEA discovered since 2001. Tim Spahr, the Director of the Minor Planet Center, reports that this was an MPC misidentification. Observations of three routine Main Belt Asteroids were incorrectly linked. There is no NEA and no orbit.
--
+++++++++++++++++++++++++++++++++++++++++++
NEO News (now in its fourteenth year of distribution) is an informal compilation of news and opinion dealing with Near Earth Objects (NEOs) and their impacts. These opinions are the responsibility of the individual authors and do not represent the positions of NASA, Ames Research Center, the International Astronomical Union, or any other organization. To subscribe (or unsubscribe) contact dmorrison@arc.nasa.gov. For additional information, please see the website http://impact.arc.nasa.gov. If anyone wishes to copy or redistribute original material from these notes, fully or in part, please include this disclaimer.
From AICN/Variety: ABC Picks Up Moon-Collision Sci-Fi Miniseries "Impact" (Moon on Collision Course With Earth)
Synposis from IMDB:
While the entire world watches the largest meteor shower in 10,000 years, a rogue asteroid, hidden by the meteor field, smashes into the moon in a tremendous explosion of rock and debris. Fragments from the asteroid, and even from the moon itself, penetrate Earth's atmosphere and make impact. Even though the initial damage is minimal, nerves are frayed throughout the planet. There is significant physical damage to the lunar surface, but experts quickly conclude there will be no lasting ramifications. Then strange anomalies begin to manifest themselves on Earth. It starts small - cell phone disruptions, unusual static charges and odd tidal behavior. The world's leading scientists, including Alex Kittner, Maddie Rhodes and Roland Emerson, begin piecing together evidence that suggests the moon's properties, and its orbit, may have been permanently altered. Their fears are realized when the anomalies increase to the point where the effect of "simulated" gravity is being manipulated by increased electromagnetic surges coming from the moon. People, cars and other objects are rendered momentarily weightless in random, isolated areas around the globe. Alex, Maddie, Roland and the rest of their team soon discover something far worse - the moon's new orbit has put it on a collision course with Earth! The world now has 39 days to stop it or Earth, and all of mankind, will perish. After a failed attempt by the United States to destroy the moon, our heroes bring all the countries of the world together in one last hope for humanity - an international mission to the moon itself where astronauts will attempt to reverse the magnetic effects and restore the moon to its original orbit. Alex, whose children are now missing after the latest rampage of anti-gravity, is emotionally torn as he must now join Roland and two other astronauts on the Earth saving mission into space. It is a race against time as the two celestial bodies are drawn closer and closer to impact, the world united, watching and praying, the survival of mankind in the balance.
From a Variety article...
BERLIN -- ABC has picked up "Impact," a four-hour sci-fi mini-series about humanity's efforts to survive after the moon is hit by a meteor and enters into a collision course with Earth.
NBC Universal's Sci Fi Channel took second-window rights to the mini, while Sony Pictures Home Entertainment acquired video rights.
The $14 million mini is produced by Germany's Tandem Communications, Hollywood-based Jaffe/Braunstein Entertainment and Canada's Muse Entertainment Enterprises.
It's the latest international collaboration for Munich-based Tandem as it continues to broaden its scope in the development, financing, production and worldwide distribution of event TV projects.
Directed by Michael J. Rohl ("Smallville," "Supernatural"), "Impact" stars David James Elliott ("JAG"), Natasha Henstridge ("Eli Stone"), Steven Culp ("Desperate Housewives") and James Cromwell ("W.").
Link: Aint It Cool News Post
Link: Variety Article
Link: IMDB Entry for Impact (2008)
While the entire world watches the largest meteor shower in 10,000 years, a rogue asteroid, hidden by the meteor field, smashes into the moon in a tremendous explosion of rock and debris. Fragments from the asteroid, and even from the moon itself, penetrate Earth's atmosphere and make impact. Even though the initial damage is minimal, nerves are frayed throughout the planet. There is significant physical damage to the lunar surface, but experts quickly conclude there will be no lasting ramifications. Then strange anomalies begin to manifest themselves on Earth. It starts small - cell phone disruptions, unusual static charges and odd tidal behavior. The world's leading scientists, including Alex Kittner, Maddie Rhodes and Roland Emerson, begin piecing together evidence that suggests the moon's properties, and its orbit, may have been permanently altered. Their fears are realized when the anomalies increase to the point where the effect of "simulated" gravity is being manipulated by increased electromagnetic surges coming from the moon. People, cars and other objects are rendered momentarily weightless in random, isolated areas around the globe. Alex, Maddie, Roland and the rest of their team soon discover something far worse - the moon's new orbit has put it on a collision course with Earth! The world now has 39 days to stop it or Earth, and all of mankind, will perish. After a failed attempt by the United States to destroy the moon, our heroes bring all the countries of the world together in one last hope for humanity - an international mission to the moon itself where astronauts will attempt to reverse the magnetic effects and restore the moon to its original orbit. Alex, whose children are now missing after the latest rampage of anti-gravity, is emotionally torn as he must now join Roland and two other astronauts on the Earth saving mission into space. It is a race against time as the two celestial bodies are drawn closer and closer to impact, the world united, watching and praying, the survival of mankind in the balance.
From a Variety article...
BERLIN -- ABC has picked up "Impact," a four-hour sci-fi mini-series about humanity's efforts to survive after the moon is hit by a meteor and enters into a collision course with Earth.
NBC Universal's Sci Fi Channel took second-window rights to the mini, while Sony Pictures Home Entertainment acquired video rights.
The $14 million mini is produced by Germany's Tandem Communications, Hollywood-based Jaffe/Braunstein Entertainment and Canada's Muse Entertainment Enterprises.
It's the latest international collaboration for Munich-based Tandem as it continues to broaden its scope in the development, financing, production and worldwide distribution of event TV projects.
Directed by Michael J. Rohl ("Smallville," "Supernatural"), "Impact" stars David James Elliott ("JAG"), Natasha Henstridge ("Eli Stone"), Steven Culp ("Desperate Housewives") and James Cromwell ("W.").
Link: Aint It Cool News Post
Link: Variety Article
Link: IMDB Entry for Impact (2008)
09 March 2009
New York Times Article: The Lure of Rocks From Outer Space
Some comments the editors of the New York Times solicited from various people including:
- Seth Shostak, astronomer at the SETI Institute
- Susan Marie Groppi, editor of Strange Horizons
- Donald K. Yeomans, NASA’s Near-Earth Object Program
- Neil deGrasse Tyson, astrophysicist
- Carolyn Collins Petersen, blogger at The Spacewriter
- Lewis Dartnell, astrobiologist
"The Lure of Rocks From Outer Space"
06 March 2009
Link: New York Times Article
- Seth Shostak, astronomer at the SETI Institute
- Susan Marie Groppi, editor of Strange Horizons
- Donald K. Yeomans, NASA’s Near-Earth Object Program
- Neil deGrasse Tyson, astrophysicist
- Carolyn Collins Petersen, blogger at The Spacewriter
- Lewis Dartnell, astrobiologist
"The Lure of Rocks From Outer Space"
06 March 2009
Link: New York Times Article
University of Nebraska College of Law Conference on NEO Law and Policy
University Of Nebraska College Of Law is proud to present the Near-Earth Objects: Risks, Responses and Opportunities – Legal Aspects, Space and Telecommunications Law Conference.
Highlights include:
- Multiple presentations on the Association of Space Explorers (ASE) on their U.N. action plan
- Paul Damphousse will be talking about a recent U.S. government simulation on NEO mitigation and emergency response.
Date: 23-24 April 2009
Location: The Cornhusker, a Marriott Hotel and at the University of Nebraska Law College (Lincoln, Nebraska).
Link: Conference Registration
Link: Conference Website with preliminary program
Highlights include:
- Multiple presentations on the Association of Space Explorers (ASE) on their U.N. action plan
- Paul Damphousse will be talking about a recent U.S. government simulation on NEO mitigation and emergency response.
Date: 23-24 April 2009
Location: The Cornhusker, a Marriott Hotel and at the University of Nebraska Law College (Lincoln, Nebraska).
Link: Conference Registration
Link: Conference Website with preliminary program
08 March 2009
NEO News (03/07/09) Newsworthy NEAs: 2009DD45 & 2008TN166
From Dave Morrison.
NEO News (03/07/09) Newsworthy NEAs: 2009DD45 & 2008TN166
The past week has seen lots of news coverage of 2009DD45, a 30m NEA that passed within about 70,000 km of Earth. Something this large comes this close only once every few years. Of greater interest to NEO scientists is 2008TN166, the largest NEA discovered in the past 8 years (with a mass a million times greater than DD45).
I also note the following interesting blogs from the New York Times and Discovery on the asteroid impact issue, stimulated by the close pass by DD45:
http://roomfordebate.blogs.nytimes.com/2009/03/06/the-lure-of-rocks-from-outer-space/
http://blogs.discovermagazine.com/badastronomy/2009/03/08/why-do-killer-asteroids-fascinate-us/
David Morrison
===========================
===========================
2009DD45
Following are several news reports on the close pass of DD45. It such cases the main press speculation is how much damage it would have caused had it hit the Earth. At the lower end of its estimated size, a diameter of about 20m, it would likely have disintegrated too high to do any ground damage, but at the upper end of the estimated size it would have been comparable to the Tunguska 10-megaton blast in Siberia a century ago. We can expect about 100 NEAs this large to pass this close to Earth for every one that hits. The discovery of this one is another testimony to the continuing success of the Spaceguard survey, even though it is much smaller than the Spaceguard target population of NEAs larger than 1 km. Because it is so small, DD45 was found only two days before its fly-by of Earth on Monday March 2. Following is some press coverage of this event.
DM
==========================
SPACE ROCK 2009DD45 BUZZES EARTH
Sky & Telescope on-line (March 1)
Late word out of the IAU's Minor Planet Center: a small asteroid will pass close to Earth tomorrow (March 2nd) at 13:44 Universal Time. How close? The MPC's Timothy Spahr calculates that it'll be 0.00047 astronomical unit from Earth's center. That's only about 40,000 miles (63,500 km) up - well inside the Moon's orbit and roughly twice the altitude of most communications satellites!
This little cosmic surprise, designated 2009DD45, turned up two days ago as a 19th-magnitude blip in images taken by Rob McNaught at Siding Spring Observatory in Australia. It was already within 1_ million miles of Earth and closing fast.
Thankfully, the news media have become less sensationalistic when it comes to these asteroidal close calls - especially since one actually struck our planet last October 7th, at night, and the impact went virtually unnoticed.
So why post this? Well, we figured someone might want to watch it zip by at up to a half degree per minute! Even though it's small, likely no more than 100 feet (30 meters) across, it'll brighten to magnitude 10_ at its closest - easily within reach of an 8-inch backyard telescope.
By the way, this isn't the closest "near-miss" asteroidal fragment on record. According to the MPC, tiny 2004FU162 skirted just 4,000 miles from us on March 31, 2004.
===========================
SURPRISE ASTEROID BUZZED EARTH MONDAY
Victoria Jaggard, National Geographic News
March 2, 2009
Sky-watchers in Asia, Australia, and the Pacific islands welcomed a surprise guest Monday: an asteroid that passed just 41,010 miles (66,000 kilometers) above Earth. Discovered only days ago, asteroid 2009DD45 zipped between our planet and the Moon at 13:44 universal time (8:44 a.m. ET). The asteroid was moving at about 12 miles (20 kilometers) a second when it was closest to Earth.
"We get objects passing fairly close, or closer than this, every few months," Timothy Spahr, director of the International Astronomical Union's Minor Planet Center in Massachusetts, said in an email. "Also, though, note these are only the ones that are discovered. Many more pass this close undetected"-as asteroid 2009DD45 nearly did. Astronomers didn't notice the oncoming asteroid until February 28, when it showed up as a faint dot in pictures taken at the Siding Spring Observatory in Australia. At that point the asteroid was already a mere 1.5 million miles (2.4 million kilometers) from Earth, and closing in fast.
=============================
ASTEROID PASSES CLOSE TO EARTH
By Alan Duke, CNN
You had a close encounter with a 40-yard-wide asteroid this week, but the astronomer who first spotted the large rock said it's nothing to worry about. Asteroid 2009DD45 on Monday passed within 38,000 miles of Earth, less than twice the height of the geostationary satellites we depend on for communications, according to Robert McNaught of the Australian National University.
McNaught, who watches for asteroids with his telescope 250 miles northwest of Sydney, Australia, discovered the approaching rock last week. "It's not something to worry about, but something to be aware of," he said.
While a direct hit on Earth could be a devastating natural disaster, McNaught said keeping track of asteroids can make a hit "potentially preventable. There is the possibility of pushing it off course, if you have decades of advance warning," McNaught said. "If you have only a few days, you can evacuate the area of impact, but there's not a great deal [else] you can do."
The 2009 DD45 asteroid circles the sun every 18 months, but its path will not threaten this planet at least for the next century, he said.
The number of "potentially harmful asteroids" discovered each year has grown dramatically over the past decade as "systematic programs" to scan the skies have been put in place, McNaught said. Nearly 100 new ones have been found in each of the past several years, he said.
============================
SPACE ROCK MAKES CLOSE APPROACH
BBC
An asteroid which may be as big as a ten-storey building has passed close by the Earth, astronomers say. The object, known as 2009DD45, thought to be 21-47m (68-152ft) across, raced by our planet at 1344 GMT on Monday. The gap was just 72,000 km (44,750 miles); a fifth of the distance between our planet and the Moon. It is in the same size range as a rock which exploded over Siberia in 1908 with the force of 1,000 atomic bombs. The object was first reported on Saturday by the Siding Spring Survey, a near-Earth object search programme in Australia.
It was confirmed by the International Astronomical Union's Minor Planet Centre (MPC), which catalogues Solar System objects. The closest recent flyby listed by the MPC is 2004FU162, a small asteroid about 6m (20ft) across which came within about 6,500km (4,000 miles) of our planet in March 2004.
"There is still a lot of debate over how big the Tunguska object was," Professor Alan Fitzsimmons, an astronomer at Queens University Belfast, told BBC News. "It was always thought to be 50 or 70m across. But some recent calculations have implied it may have been even smaller than that - maybe down to 30m in size. There's a large uncertainty there, but it puts (this object) in the same ballpark."
A United Nations working group on near-Earth objects (NEOs) met last month to discuss drafting international procedures for handling the asteroid threat. Dr Richard Crowther, chair of the UN Working Group on Near-Earth Objects, commented: "Although we will meet formally again in June of this year to advance our work on this important issue, I am sure we will discuss the implications of the 2009DD45 close approach informally before then.
He told BBC News: "Such unanticipated near-misses - at least in astronomical terms - demonstrate the need for the global community to establish the means to mitigate this impact threat."
==========================
Among the worst coverage was a report on Fox News, showing the asteroid with a tail like a comet grazing the atmosphere and making a swishing sound, while a female reporter giggled in the background.
==========================
==========================
2008TN166
An asteroid discovered in late 2008 turns out to be the brightest (and presumably largest) new NEA since 2001. Its diameter is apparently between 3 and 4 km. Alan Harris (of the Space Science Institute) notes that we have discovered about 82 objects 3 km or larger. He estimates the Spaceguard Survey is at least 95% complete in that size range, so he guesses there are only about 4 more to find, most likely in rather unusual long-period orbits.
The asteroid, 2008TN166, has a relatively long period of about 6 years. It was 4.27 AU from the Sun when it was discovered, nearly as far away as Jupiter. Such asteroids are sometimes referred to as NEAs with comet-like orbits. It was at perihelion in 2001 and 2007. Such large NEAs can still be detected fairly far from the Sun. It was discovered by the Mount Lemmon Survey, which detects objects down to magnitude 22. TN166 was favorably placed for observing in 2007 when it was much closer, but apparently nobody happened to be looking at the right place at the right time then.
DM (with help from Don Gennery and Al Harris)
--
+++++++++++++++++++++++++++++++++++++++++++
NEO News (now in its fourteenth year of distribution) is an informal compilation of news and opinion dealing with Near Earth Objects (NEOs) and their impacts. These opinions are the responsibility of the individual authors and do not represent the positions of NASA, Ames Research Center, the International Astronomical Union, or any other organization. To subscribe (or unsubscribe) contact dmorrison@arc.nasa.gov. For additional information, please see the website http://impact.arc.nasa.gov. If anyone wishes to copy or redistribute original material from these notes, fully or in part, please include this disclaimer.
NEO News (03/07/09) Newsworthy NEAs: 2009DD45 & 2008TN166
The past week has seen lots of news coverage of 2009DD45, a 30m NEA that passed within about 70,000 km of Earth. Something this large comes this close only once every few years. Of greater interest to NEO scientists is 2008TN166, the largest NEA discovered in the past 8 years (with a mass a million times greater than DD45).
I also note the following interesting blogs from the New York Times and Discovery on the asteroid impact issue, stimulated by the close pass by DD45:
http://roomfordebate.blogs.nytimes.com/2009/03/06/the-lure-of-rocks-from-outer-space/
http://blogs.discovermagazine.com/badastronomy/2009/03/08/why-do-killer-asteroids-fascinate-us/
David Morrison
===========================
===========================
2009DD45
Following are several news reports on the close pass of DD45. It such cases the main press speculation is how much damage it would have caused had it hit the Earth. At the lower end of its estimated size, a diameter of about 20m, it would likely have disintegrated too high to do any ground damage, but at the upper end of the estimated size it would have been comparable to the Tunguska 10-megaton blast in Siberia a century ago. We can expect about 100 NEAs this large to pass this close to Earth for every one that hits. The discovery of this one is another testimony to the continuing success of the Spaceguard survey, even though it is much smaller than the Spaceguard target population of NEAs larger than 1 km. Because it is so small, DD45 was found only two days before its fly-by of Earth on Monday March 2. Following is some press coverage of this event.
DM
==========================
SPACE ROCK 2009DD45 BUZZES EARTH
Sky & Telescope on-line (March 1)
Late word out of the IAU's Minor Planet Center: a small asteroid will pass close to Earth tomorrow (March 2nd) at 13:44 Universal Time. How close? The MPC's Timothy Spahr calculates that it'll be 0.00047 astronomical unit from Earth's center. That's only about 40,000 miles (63,500 km) up - well inside the Moon's orbit and roughly twice the altitude of most communications satellites!
This little cosmic surprise, designated 2009DD45, turned up two days ago as a 19th-magnitude blip in images taken by Rob McNaught at Siding Spring Observatory in Australia. It was already within 1_ million miles of Earth and closing fast.
Thankfully, the news media have become less sensationalistic when it comes to these asteroidal close calls - especially since one actually struck our planet last October 7th, at night, and the impact went virtually unnoticed.
So why post this? Well, we figured someone might want to watch it zip by at up to a half degree per minute! Even though it's small, likely no more than 100 feet (30 meters) across, it'll brighten to magnitude 10_ at its closest - easily within reach of an 8-inch backyard telescope.
By the way, this isn't the closest "near-miss" asteroidal fragment on record. According to the MPC, tiny 2004FU162 skirted just 4,000 miles from us on March 31, 2004.
===========================
SURPRISE ASTEROID BUZZED EARTH MONDAY
Victoria Jaggard, National Geographic News
March 2, 2009
Sky-watchers in Asia, Australia, and the Pacific islands welcomed a surprise guest Monday: an asteroid that passed just 41,010 miles (66,000 kilometers) above Earth. Discovered only days ago, asteroid 2009DD45 zipped between our planet and the Moon at 13:44 universal time (8:44 a.m. ET). The asteroid was moving at about 12 miles (20 kilometers) a second when it was closest to Earth.
"We get objects passing fairly close, or closer than this, every few months," Timothy Spahr, director of the International Astronomical Union's Minor Planet Center in Massachusetts, said in an email. "Also, though, note these are only the ones that are discovered. Many more pass this close undetected"-as asteroid 2009DD45 nearly did. Astronomers didn't notice the oncoming asteroid until February 28, when it showed up as a faint dot in pictures taken at the Siding Spring Observatory in Australia. At that point the asteroid was already a mere 1.5 million miles (2.4 million kilometers) from Earth, and closing in fast.
=============================
ASTEROID PASSES CLOSE TO EARTH
By Alan Duke, CNN
You had a close encounter with a 40-yard-wide asteroid this week, but the astronomer who first spotted the large rock said it's nothing to worry about. Asteroid 2009DD45 on Monday passed within 38,000 miles of Earth, less than twice the height of the geostationary satellites we depend on for communications, according to Robert McNaught of the Australian National University.
McNaught, who watches for asteroids with his telescope 250 miles northwest of Sydney, Australia, discovered the approaching rock last week. "It's not something to worry about, but something to be aware of," he said.
While a direct hit on Earth could be a devastating natural disaster, McNaught said keeping track of asteroids can make a hit "potentially preventable. There is the possibility of pushing it off course, if you have decades of advance warning," McNaught said. "If you have only a few days, you can evacuate the area of impact, but there's not a great deal [else] you can do."
The 2009 DD45 asteroid circles the sun every 18 months, but its path will not threaten this planet at least for the next century, he said.
The number of "potentially harmful asteroids" discovered each year has grown dramatically over the past decade as "systematic programs" to scan the skies have been put in place, McNaught said. Nearly 100 new ones have been found in each of the past several years, he said.
============================
SPACE ROCK MAKES CLOSE APPROACH
BBC
An asteroid which may be as big as a ten-storey building has passed close by the Earth, astronomers say. The object, known as 2009DD45, thought to be 21-47m (68-152ft) across, raced by our planet at 1344 GMT on Monday. The gap was just 72,000 km (44,750 miles); a fifth of the distance between our planet and the Moon. It is in the same size range as a rock which exploded over Siberia in 1908 with the force of 1,000 atomic bombs. The object was first reported on Saturday by the Siding Spring Survey, a near-Earth object search programme in Australia.
It was confirmed by the International Astronomical Union's Minor Planet Centre (MPC), which catalogues Solar System objects. The closest recent flyby listed by the MPC is 2004FU162, a small asteroid about 6m (20ft) across which came within about 6,500km (4,000 miles) of our planet in March 2004.
"There is still a lot of debate over how big the Tunguska object was," Professor Alan Fitzsimmons, an astronomer at Queens University Belfast, told BBC News. "It was always thought to be 50 or 70m across. But some recent calculations have implied it may have been even smaller than that - maybe down to 30m in size. There's a large uncertainty there, but it puts (this object) in the same ballpark."
A United Nations working group on near-Earth objects (NEOs) met last month to discuss drafting international procedures for handling the asteroid threat. Dr Richard Crowther, chair of the UN Working Group on Near-Earth Objects, commented: "Although we will meet formally again in June of this year to advance our work on this important issue, I am sure we will discuss the implications of the 2009DD45 close approach informally before then.
He told BBC News: "Such unanticipated near-misses - at least in astronomical terms - demonstrate the need for the global community to establish the means to mitigate this impact threat."
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Among the worst coverage was a report on Fox News, showing the asteroid with a tail like a comet grazing the atmosphere and making a swishing sound, while a female reporter giggled in the background.
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2008TN166
An asteroid discovered in late 2008 turns out to be the brightest (and presumably largest) new NEA since 2001. Its diameter is apparently between 3 and 4 km. Alan Harris (of the Space Science Institute) notes that we have discovered about 82 objects 3 km or larger. He estimates the Spaceguard Survey is at least 95% complete in that size range, so he guesses there are only about 4 more to find, most likely in rather unusual long-period orbits.
The asteroid, 2008TN166, has a relatively long period of about 6 years. It was 4.27 AU from the Sun when it was discovered, nearly as far away as Jupiter. Such asteroids are sometimes referred to as NEAs with comet-like orbits. It was at perihelion in 2001 and 2007. Such large NEAs can still be detected fairly far from the Sun. It was discovered by the Mount Lemmon Survey, which detects objects down to magnitude 22. TN166 was favorably placed for observing in 2007 when it was much closer, but apparently nobody happened to be looking at the right place at the right time then.
DM (with help from Don Gennery and Al Harris)
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NEO News (now in its fourteenth year of distribution) is an informal compilation of news and opinion dealing with Near Earth Objects (NEOs) and their impacts. These opinions are the responsibility of the individual authors and do not represent the positions of NASA, Ames Research Center, the International Astronomical Union, or any other organization. To subscribe (or unsubscribe) contact dmorrison@arc.nasa.gov. For additional information, please see the website http://impact.arc.nasa.gov. If anyone wishes to copy or redistribute original material from these notes, fully or in part, please include this disclaimer.
02 March 2009
2009 DD45 Roundup
Near Earth Asteroid 2009 DD45 on 2009 March 2 - moving at about 500"/minute (from Canberra, Australia).
2009 DD45, a small Near Earth Asteroid, passed by the Earth on 3:44 UT on 02 March 2009 at a close approach distance of 74,800 km/46,478.5 miles/0.000482 AU.
Link: Universe Today Article
Link: MPC Information on 2209 DD45
Link: Sky and Telescope Article
Link: JPL Small-Body Database Browser for 2009 DD45
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