Sunday, February 17, 2013
Friday was an unusual day for February in western Washington. The sky was desert-clear in the afternoon once the Sun burned off the morning fog. From Seattle, Mount Rainier loomed like a titan's throne in the south, and the Olympic mountains were clearly present across Puget Sound to the west. Most days this time of year the western mountains are shrouded in the clouds that dump rain forest levels of rain on the peninsula, but on Friday they rose like the teeth of a saw blade, white with the immaculate reflectivity of winter's snow. This weekend's weather has been more typical. The skies have mostly been gray, and the afternoons filled with the sound of raindrops on glass.
As atypical as the weather was in Seattle, it was much more out of the ordinary in Chelyabinsk than anywhere else on Earth. The largest meteoroid to collide with Earth since the Tunguska Event of 1908 hit the atmosphere with a train of light that outshone the Sun and a shock wave loud enough to break thousands of windows and collapse at least one large building across the city. The energy released by the asteroid was something like a typical ICBM warhead, a level of energy as beyond human imagination as the scale of the oceans.
Some in the media will downplay this event, reminding us that these impacts are very rare on the scale of a human lifetime. This is true. It's unlikely that anyone alive today will live to see a larger collision between a near-Earth object and our home planet. There are other, clearer, more present dangers to our cities and farms than these collisions, and it makes sense that more time and industry has been devoted to understanding and mitigating the effects on civilization of earthquakes, hurricanes, floods, volcanoes, and tsunamis than asteroid collisions.
Still, we're doing meaningful things to mitigate those threats because they're real and obvious. The threat from asteroid and comet impacts is less obvious because of the rarity of these events, but it's no less real. Shouldn't we be doing something about asteroid defense, now that we have the technology to make it happen? There are many credible options on the table for how to deflect a large object on a collision course with Earth so long as we have a few years' lead time. Finding objects in time to have that head start is within the capabilities of well-incentivized amateurs. The challenges aren't technical, they're political and financial.
Rather than dumping the responsibility on NASA, why not charge the world's defense departments with the defense of the world? Most of the objects capable of causing regional damage on impact could be found, and a demonstration mission could be done to prove the concept of asteroid deflection for about half a billion dollars. That's about a thousandth what the US DoD receives every year, sequestration or not. People tend to be reactionary, and don't want to respond to threats until they become too painful to ignore. My hope is that the rain from space over the Urals will get people to react.
Because the one thing we know for certain is that the next one is out there.