Wednesday, October 27, 2010

Challenger Center: "Asteroid Impact Hazards"

CCSSE has a 10 minute YouTube video from the Challenger Center (with Rita Carl) (site ) by Dr. Alan Stern, “Asteroid Impact Hazards

I was motivated to look for this by a Bing video, less than one minute, of an asteroid hitting the Earth and with the impact surrounding Earth with a huge dust cloud. I can’t find that now.

Stern’s discussion is less ominous, but he says there is a big effort to track all asteroids in remotely near Earth orbits of 1 km in diameter or more. It would be possible to deflect one by changing reflectivity so that the pressure of sunlight changes the orbit slightly, or even the mass of a spacecraft could do so. It would not be a good idea to blow one apart. The video contained animated reconstructions of Tunguska in 1908, and of the dinosaur-killing impact on the Yucatan 65 million years ago leading to the rise of mammals (and us).

Various other sources says that a 1 km asteroid hitting the ocean could completely destroy the Earth’s ozone layer.

By the way, take a look at Sam Hughes "recipes" on Live Science, "Top 10 Ways to Destroy Earth", link. I like #8, make your own mini black hole  (as if neutronium were mentioned in every cookbook)-- except that the singularity point replacing Earth would eventually evaporate in Hawking radiation, leaving nothing.  I like #10, too: Existence fails, and the one about the contagious strangelet. 

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