A small asteroid, 2008 TC3, entered Earth’s atmosphere last night, October 6, at 10:46 pm EDT (October 7, 0246 UTC). The rock, 1-5 meters in diameter, burned up harmlessly over northern Sudan. The crew of a KLM jetliner about 750 miles away reported seeing the flash from the fireball, which released about a kiloton of explosive energy into the atmosphere. No damage was expected on the ground.
Such fireballs, or bolides, enter Earth’s atmosphere routinely. What marked this Near Earth Object‘s demise was that it was detected and its entry predicted through the efforts of the Spaceguard Survey team in Tucson, AZ. Warning time was a mere 24 hours or so, and there are hundreds of thousands of such objects, bigger than about 40 m (large enough to strike the surface) trooping through the inner solar system within reach of Earth’s orbit. We know of only 5600 or so of these Near Earth Objects. As our telescopes get better, we’ll be finding thousands more, and of those, a few dozen will be found to pose an uncomfortably high probability of hitting Earth with enough force to cause damage to lives or property.
To address that unseen but certain threat, the Near Earth Object Committee of the Association of Space Explorers submitted a report, prepared by its Panel on Asteroid Threat Mitigation, to the United Nations on Sep. 25, 2008. The Panel proposes a decision-making process to deal with threatening asteroids for adoption by the international community, working through the existing structures of the United Nations.
An excerpt of that report is available at the Association of Space Explorer site, here. As a member of the Committee, I worked with the Panel through its two years of deliberations, ending in the delivery of the report last month. Now it’s up to the United Nations and the world’s peoples to prepare for some future asteroid strike, potentially much more dangerous than the harmless light show put on by 2008 TC3.
Video of 2008 TC3 here:
An earlier video of an Australian fireball:
NASA diagram of 2008 TC3 impact trajectory.