Thanks. Gene Shoemaker said that, once an object gets to a mile in diameter, the energy released by its impact on the Earth would exceed the energy released if one took all the nuclear weapons in the world, put 'em in a pile, and set them off simultaneously. Of course, that's give or take a dozen miles per second of terminal velocity. ;')
"When we learned that our team had been assigned the topic of "Planetary Defense," we admittedly did what most people do when they first consider the subject: we laughed. This phenomenon is commonly referred to as the giggle factor, and we have seen it many times during the ensuing months of our research and briefings.
Gene Shoemaker said that, once an object gets to a mile in diameter, the energy released by its impact on the Earth would exceed the energy released if one took all the nuclear weapons in the world, put 'em in a pile, and set them off simultaneously. Of course, that's give or take a dozen miles per second of terminal velocity. ;')
You're just asking for it with that info. I don't think I ever posted this link before or not, but...
How to destroy the Earth
http://qntm.org/destroy