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Neil deGrasse Tyson On How To Stop a Meteor Hitting the Earth
An anonymous reader writes "Astrophysicist Neil deGrasse Tyson talks stopping extinction-level meteor hits: '...Here in America, we're really good at blowing stuff up and less good at knowing where the pieces land, you know...So, people who have studied the problem generally – and I'm in this camp – see a deflection scenario is more sound and more controllable. So if this is the asteroid and it's sort of headed toward us, one way is you send up a space ship and they'll both feel each other. And the space ship hovers. And they'll both feel each other's gravity. And they want to sort of drift toward one another. But you don't let that happen. You set off little retro rockets that prevent it. And the act of doing so slowly tugs the asteroid into a new orbit.'"
I'm going to assume Astrophysicist Neil deGrasse Tyson is a much better source than you.
But the point is correct. The gravitational attraction of a spaceship to an asteroid is a weak force. It means you can only a apply a force equal to the weight of the ship on the asteroid. Also, the momentum of the propellant from the rocket pushes against the asteroid, countering the thrust of the rocket. (Unless you direct the rocket away from the asteroid, in which case the rocket escapes from the asteroid.) It's a bad idea.
Do they not teach basic science in the US anymore? The fact that it would work should be something can be easily proven by anyone who has taken highschool physics. You do realize that rockets don't take off because they're pushing against the ground, right? You just need to move the center of gravity the tiniest amount. When you're traveling a billion or two miles, and you're trying to miss something that is only 13,000km across, you don't need to put a lot of pressure on it, you just need to put a little pressure for a very long time.