Monday, February 18, 2013

A quick refresher on the problems with playing God

So by now, we've all read about the meteor that exploded over Russia last week, right? It has been covered extensively, so I won't waste too much time rehashing it. Suffice to say it was an impressive look at what nature can do with a little gravity, velocity, friction and deceleration.

For a few seconds, the meteor--called a "bolide" when it turns into this sort of fireball--shined brighter than the rising sun...

... and its explosion, caused by the intense, uneven heating of its surfaces as it streaked through the atmosphere at about 11 miles per second, released energy equivalent to the detonation of 500,000 tons of TNT. Because the explosion happened several miles above the ground, the blast effects weren't devastating... but were still dramatic:

For comparison's sake, 500 kilotons is roughly 25 times the yield of "Fat Man," the nuclear weapon dropped on Hiroshima, Japan. And it was caused, basically, by a fast-moving rock.

Which brings us to playing God. I thought I had written about this before, but a quick search of The Blog tells me I apparently haven't: the United States has for decades kicked around ideas for a space-based kinetic-energy weapon called Project Thor--and nicknamed "Rods from God." The gist is that orbiting satellites would be armed with long, pointy, semi-guided rods made of super-dense tungsten, roughly the size of telephone poles. Give them a push in the right direction, and these heavy things deorbit and hit something on the ground.

Because it is deorbiting, it literally has to slow down, which means it will only impact at Mach 10--almost six times slower than the Chelyabinsk bolide. The energy released would be the equivalent of a mere 12 or so tons of TNT.

It's easy to see why people might be terrified of a random space rock blowing up over their heads--you can't stop it, and you can't see it coming. And it's exactly why putting weapons in space is not a good idea. It's bad enough that a bad roll of the cosmic dice could wipe out a city. But giving ourselves that power does nothing but increase the odds of unstoppable death falling from the sky.

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