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.

Last Saturday, October 4, I was a guest in Coalwood, WV, at the 10th annual October Sky Festival, hosted by Coalwood citizens and best-selling author Homer Hickam. The day was blessed with beautiful early autumn weather: temperatures about 70 under a cloudless blue sky. The forested ridges surrounding the little town (population, 180, down from 2000 sixty years ago) where Homer grew up were brushed lightly with the first traces of yellow, orange, and rust-red. The mining town’s main street was lined with art and craft vendors, food stalls, and plenty of happy families.

Along with Homer’s boyhood pals, I participated in a series of model rocket launches just after lunch at “Cape Coalwood,” where Homer and the Rocket Boys once lofted their home-built missiles. Most of Saturday’s rockets managed to parachute back into the former mining dump site without damage, although the surrounding tall trees claimed a few reentering vehicles.

Homer’s latest book is Red Helmet, and he always had a line out front of the Methodist Church for signing. My table was on the church’s front lawn, where I signed copies of Hell Hawks! and Sky Walking through the day. With both my grandfathers having worked in the coal mines of Wilkes-Barre, PA, my visit to Coalwood was a glimpse into their lives 75 years ago. For a day, at least, I could trace a direct path from the mines to the stars. Plan on visiting the October Sky Festival in 2009.