Perhaps it’s the aroma of borscht, or maybe just the fact that it’s a big country, but Russia seems to be a favorite target for asteroids.
On Friday February 15, a rock the size of a truck slammed into the atmosphere above Chelyabinsk, a city of about one million people on the eastern flank of the Ural Mountains. The resulting shock wave blew out windows, collapsed a roof, and – as consequence – injured a thousand people. If this unannounced visitor had been a few times larger, it might have made it all the way to the ground, producing a crater that – depending on location – would either be the scene of indescribable carnage, or merely a future tourist attraction.
In 1908, Russia experienced something similar when an asteroid the heft of an office building ruptured above the Tunguska River valley in Siberia. The impact had the energy of several hundred atomic bombs, and leveled millions of trees. No people were injured or killed, simply because no one lived nearby.
Still, the Chelyabinsk meteor is a reminder – in case one was needed – of the fact that there are 40 or 50 thousand rocks the size of a football field or larger cruising our celestial neighborhood. The larger of these – the ones that could wreak truly widespread devastation – have been mostly discovered and charted. So that’s the good news: We’ll have ample warning if a rock comparable to the impactor that decimated the dinosaurs is headed our way.
But smaller rocks, like the one that lit up the sky above Chelyabinsk, remain elusive. It’s NASA’s intention to seek them out over the course of the next two decades. Estimated cost of this massive reconnaissance project? About $500 per asteroid. That’s inexpensive insurance.
Asteroids are the major subject of study of Peter Jenniskens, here at the SETI Institute. In particular, he’s tracked down bits of these celestial projectiles in the Sudan and in California’s gold country. They can tell us something about the origins of our solar system, of course. But they are very much like the big cats of Africa … fascinating to study, but deserving of caution.