Deflecting an Asteroid

You may have heard that an asteroid passed close to the Earth this week; here’s a video of it traveling through the sky, recorded by an astronomer named BJ Fulton and found via Astronomy Blog:

As a result of this fly-by there’s been a lot of asteroid talk lately, and Universe Today has a very interesting article on what our options would be if an asteroid were in fact on a collision course with Earth. All it might take is an asteroid 1 kilometre in diameter to end human civilization, apparently, which really sucks. Here’s Wikipedia’s description of the likely effects of the asteroid that created the Chicxulub crater and possibly contributed to the extinction of dinosaurs (“the Cretacious-Paleogene extinction event”):

The impact would have caused some of the largest megatsunamis in Earth’s history, reaching thousands of meters high. A cloud of super-heated dust, ash and steam would have spread from the crater, as the impactor burrowed underground in less than a second. Excavated material along with pieces of the impactor, ejected out of the atmosphere by the blast, would have been heated to incandescence upon re-entry, broiling the Earth’s surface and possibly igniting global wildfires; meanwhile, colossal shock waves would have effected global earthquakes and volcanic eruptions. The emission of dust and particles could have covered the entire surface of the Earth for several years, possibly a decade, creating a harsh environment for living things. The shock production of carbon dioxide caused by the destruction of carbonate rocks would have led to a sudden greenhouse effect. Over a longer period, sunlight would have been blocked from reaching the surface of the earth by the dust particles in the atmosphere, cooling the surface dramatically. Photosynthesis by plants would also have been interrupted, affecting the entire food chain.

So, that sounds like a lot of fun. The asteroid in question was over 10 km in diameter, but I think an effect a tenth that size might still be problematic. So how do we stop that from happening? The article from Universe Today has some interesting answers that I can’t do justice to here – you should read it for yourself for the full scoop.

Some of the possibilities it mentions for changing an asteroid’s course are hitting it with nuclear weapons (which would be legally problematic due to space treaties), using a solar-energy-powered sail, tying ballast to it, or vaporizing part of it with lasers. Any of these schemes would take extensive planning and cooperation, so it seems that preparing for them immediately would be the safest course of action. 

It may be bad to say, but I kind of want to see this crisis happen, just to see the science jump-started and thrown into full gear. I see a supervillain motivation here, actually…

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