This area will cover relevant news of the threat to the planet from Near Earth Objects (NEOs) including concepts and designs for mitigation. All opinions are those of the author.

30 March 2006

Article on Asteroid Impacts and the Dinosaurs: Perhaps Two Impacts?

"Keller thinks dinosaurs survived the Chicxulub impact but were finished off by a larger, more catastrophic impact that happened roughly 300,000 years later. It was this later impact, Keller says, that is responsible for the K-T boundary."

"The views of Keller and her colleagues are controversial within the scientific community. Many scientists disagree with her team's interpretation of data...Recent work by other scientists, for example, has shown that fossil records could have been shuffled around by an enormous tsunami that would have followed such a significant asteroid impact. This would explain Keller's anomalous fossils, they argue."

"...Kyte dismisses the idea that an asteroid impact different from the one that occurred at Chicxulub was responsible for the dinosaur's mass extinction."

"Study stirs debate over dinosaurs’ fate" Some say evidence points away from Yucatan asteroid; others disagree"
Ker Than
30 March 2006


29 March 2006

SpaceWorks Engineering, Inc. (SEI) Becomes Sponser for 2007 Planetary Defense Conference

Atlanta-based engineering consulting firm SpaceWorks Engineering, Inc. (SEI) becomes the newest sponsor of the 2007 Planetary Defense Conference that will be taking place March 5-8, 2007 at George Washington University in Washington, D.C.

Link: Press Release

Link: 2007 Planetary Defense Conference

Activated Asteroids/ Main Belt Comets between Mars and Jupiter

"A bevy of the ice-containing bodies lies disguised as main-belt asteroids between Mars and Jupiter, claim astronomers from the University of Hawaii, US...David Jewitt and Henry Hsieh have dubbed the new population 'main belt comets'. They describe three objects with near circular, flat orbits in the asteroid belt that stream volatile materials, producing an observable tail for weeks and months at a time."

"The team believes in order to survive at such proximity to the Sun, the volatiles in the main belt comets would have to be covered by a layer of possibly carbonaceous material. They say an impact event could then uncover some of the volatiles, allowing the Sun's heat to trigger the observed outgassing."

"Clandestine comets found in main asteroid belt"
Kimm Groshong
23 March 2006


20 March 2006

Commentary on 2004 VD17, Risk Communication, and the "Purgatorio Ratio"

"Another impact scare, another risk communication mess. That is, in short, how one could sum up the latest developments in the saga of asteroid 2004 VD17."

"In the mean time, with nobody saying anything except that the Torino Scale value is two (and arguing about what this means, when it actually means nothing relevant at all), I fear that some NEO risk assessors have tied themselves into a knot."

"Thankfully, Brian Marsden has shed some light on these problems in his contribution further below. He also presents some new thoughts on the “Purgatorio Ratio”, an alternative NEO risk communication tool that aims to radically change the way information about asteroids with non-zero impact probabilities is assessed, organized, and communicated. I hope that the mess over 2004 VD17 will convince more members of the NEO community that the current risk communication system isn’t working properly and thus in urgent need of modification and improvement."

"a better—and more understandable—assessment of potential NEO hazards is provided by the ratio of the time interval spanned by the observations to the time remaining until the first possible impact date. For 2004 VD17 and the 2102 date, this “Purgatorio Ratio” (PR) is 0.014, increasing to 0.042 if one accepts the 2002 precovery observations and the 2102 threat continues to be valid. Even the 0.042 value is smaller than the PRs of 0.062 for (99942) Apophis in 2036 and 0.063 for (29075) 1950 DA in 2880. The next smaller values of PR are 0.022 for 2000 SG344 in 2068 and 0.011 for 2003 DW10 in 2046."

"Asteroid turns hot potato: when NEO risk communication becomes uncommunicative"
Benny Peiser
March 20, 2006


17 March 2006

Evidence of Possible 5km Diameter Object Impact in Antarctica

"Scientists say the evidence, if correct, points to a space rock some 5km across having crashed into the Ross Sea [Antarctica] about three million years ago."

"Researchers from the Lamont-Doherty Earth Observatory in New York have been studying a 100km-wide depression, known as Bowers Crater, under the Ross Sea."

"Space impact clue in Antarctica"
Paul Rincon
BBC News science reporter
Houston, Texas


Article on Asteroid Threat, Apophis, Etc.

"Schweickart and other scientists urged NASA to place a data-tracking radio transponder on the asteroid's surface by 2014."

"A transponder would help nail down orbital alterations caused by a phenomenon called the Yarkovsky effect. This is produced when an asteroid absorbs energy from the sun and re-radiates it back into space as heat. With one side of the asteroid lit and the other in darkness, the imbalance in thermal radiation produces a tiny acceleration. A transponder would help scientists understand how the Yarkovsky effect is influencing the asteroid's orbit."

"NASA responded to the urging with a wait-and-see proposal. 'We conclude a space mission based solely on any perceived collision hazard is not warranted at this time,' wrote Mary L. Cleave, associate administrator for NASA's science mission directorate."

"The agency believes continued optical and radio telescope observations will rule out Apophis as a threat. If not, NASA would launch a mission to the asteroid by 2018. A radio transponder, placed either in orbit or on its surface, would determine the asteroid's position in 2029 down to a few hundred feet, according to NASA."

"If an impact seems probable, a rocket would be launched to deflect the asteroid. The design phase would have to be completed by 2020 in order to launch by 2024, NASA noted."

"A 1-ton gravitational tractor could sufficiently divert Apophis outside the keyhole by hovering next to it for about a month, Lu and Love said."

"As scientists ponder that proposal, time marches on toward 2029 and 2036. Beginning this year, astronomers will lose visual and radar contact with Apophis, and the asteroid will not become visible again until 2013."

"Astronomers watch the skies for threat of deadly impact"
Bruce Lieberman
Paramus Post
March 17 2006


13 March 2006

2007 Planetary Defense Conference Website is Up

2007 Planetary Defense Conference
March 5-8, 2007
George Washington University
Washington, D.C.

"The objective of the conference is to develop a white paper that assesses the current state of our ability to discover and track near earth objects (NEOs—objects that could possibly impact Earth) and our ability to successfully deflect a threatening object should one be detected."


07 March 2006

Summary of Recent 43rd UN COPUOS Meeting: Related to Planetary Defense

The recent forty-third session of the Scientific and Technical Subcommittee of the Committee on the Peaceful Uses of Outer Space (COPUOS) was held from 20 February-3 March 2006 at the United Nations Office at Vienna, Vienna International Center, Vienna, Austria.

One of the agenda items was planetary defense. B612 Foundation Chairman Rusty Schweickart was there presenting on behalf of the Association of Space Explorers (ASE). Other presentations (see links below) included “Near-Earth objects related activities in the United Kingdom” by Mr. R. Crowther of the United Kingdom, “Near-Earth object research activities in the Republic of Korea: 2005 progress report” by Mr. Won-yong Han of the Republic of Korea, and “The need for an international near-Earth object committee” by Mr. A. MacDonald of the International Space University (ISU).

The UN press release stated the final agreement related to NEO defense as: "On near-Earth objects the Subcommittee stressed that early detection and precision of asteroids and meteors that may cross Earth’s orbit were the most effective tools for avoiding a collision, noting that any mitigating measures would require coordinated international efforts."

"Agenda of UN outer space panel: boosting medicine and averting cataclysm"
UN News Centre
March 6, 2006
Link: Press Release

Summary of 43rd UN COPUOS Scientific and Technical Subcommittee Session (February 20 - March 3, 2006)
Link: Session Reports

Presentations from the 43rd UN COPUOS Scientific and Technical Subcommittee Session Related to NEOs
Link: All Presentations

"NEO Deflection: An International Challenge"
R. Schweickart (ASE)
Link: Presentation PDF

"Near Earth objects related activities in the United Kingdom"
R. Crowther (United Kingdom)
Link: Presentation PDF

"Near-Earth object research activities in the Republic of Korea: 2005 progress report"
Wonyong Han (Republic of Korea)
Link: Presentation PDF

"The need for an international near-Earth object committee"
A. MacDonald (International Space University (ISU))
Link: Presentation PDF

06 March 2006

Roundup of Articles on Asteroid 2004 VD17

Various updates related to asteroid 2004 VD17 including specific object information and news articles:

2004 VD17 Impact Risk (from JPL)

2004 VD17 Orbital Information (from NEODys)

2004 VD17 Orbital Information (from Harvard)

2004 VD17 Wikipedia Link

Planetary Society Updates

Forums discussion

"New asteroid top of Earth's hit list"
Agen├že France-Presse
March 3, 2006

"It's the end of the world"
The Sun (UK)
Paul Sutherland

"New Asteroid Becomes Earth's Biggest Threat"
Posted by Zonk
March 2, 2006

05 March 2006

Planetary Defense Conference in 2007

Following up on the AIAA Planetary Defense Conference in 2004, there will be a second AIAA Planetary Defense Conference in 2007. Tentative plans are for this second international conference to be held in Washington, D.C., on March 5-8, 2007.

Recommendations from a similar conference in 2004 can be
accessed at

A formal announcement from the AIAA should be anticipated soon.

03 March 2006

NASA Cancels Dawn Asteroid Mission: AP Article

NASA Cancels Mission to Visit 2 Asteroids
Associated Press
Thu Mar 2, 8:52 PM ET

"NASA on Thursday canceled a mission to visit two asteroids five months after the program was told to stand down because of cost overruns and technical problems."

"The project was capped at around $371 million, project scientists said previously. But the program was ordered to stand down after scientists asked for an additional $40 million last year."

"Dawn was supposed to lift off in June on a nine-year voyage to two of the solar system's largest asteroids, Ceres and Vesta, which reside in the main asteroid belt between Mars and Jupiter."

"The Dawn mission was put on standdown last October after going over budget and suffering several setbacks that included the rupture of two xenon fuel tanks during testing, forcing engineers to reduce the amount of xenon to be loaded in the tanks."


Update from David Morrison: Summary of Known Facts About 2004 VD17

Update from David Morrison at NASA Ames Research Center on 2004 VD17:

"At the end of February, orbital calculations for near-Earth-asteroid (NEA) 2004 VD17 indicated that the risk of an impact within the next century (specifically on May 4, 2102) was higher than that of any other known asteroid. The probability, based on 687 telescopic observations spanning 475 days, is listed on the JPL NEO Program webpage as a bit less than 1 in 1000."

"There is no similar keyhole in the case of VD17 [compared to Asteroid Apophis], although it does make relatively close passes by Earth in 2032, 2041 and 2067."

"...there are no near-term opportunities for additional observations, so VD17 will probably remain at Torino scale 2 for quite some time."


01 March 2006

Article on Asteroid 2004 VD17

"On 23 February, new observations allowed researchers to more accurately calculate the orbit of the asteroid, named 2004 VD17, which was originally detected by the Massachusetts Institute of Technology's LINEAR project. Since the improvement did not rule out a potential collision with the Earth on 4 May 2102, they increased the asteroid's rating to level 2 on the Torino Scale, a relatively rare event.

So VD17 currently claims the top spot on NASA's online list of potential asteroid impacts...Despite the rarity of the yellow designation, Yeomans says 'Torino 2 is not very alarming.' He notes that the scale does not take account of how soon an impact may occur, unlike its rival, the Palermo Scale...Based on current observations, he says the asteroid has a 1 in 1600 chance of striking the Earth in 2102 and a 1 in 500,000 chance of hitting two years later. But further observations will soon refine the orbit calculation for VD17 – and hopefully ease minds."

"New asteroid at top of Earth-threat list"
Kimm Groshong
March 1, 2006

Note: Any opinions expressed on the blog are solely those of the author. The site is not sponsored by, nor does it represent the opinions of, any organization, corporation, or other entity.