The stars look the same from night to night. Nebulae and galaxies are dully immutable, maintaining the same overall appearance for thousands or millions of years. Indeed, only the sun, moon and planets - together with the occasional comet, asteroid or meteor - seem dynamic.
The Moon is a ball of left-over debris from a cosmic collision that took place more than four billion years ago. A Mars-sized asteroid - one of the countless planetesimals that were frantically churning our solar system into existence - hit the infant Earth, bequeathing it a very large natural satellite.
There is a one-in-300 chance that Earth will be struck on March 16, 2880, by an asteroid large enough to destroy civilization and possibly cause the extinction of the human race. But, on the bright side, Prince could re-release his hit song with the new refrain 'We're gonna party like its twenty-eight seventy-nine.'
Asteroids have us in our sight. The dinosaurs didn't have a space program, so they're not here to talk about this problem. We are, and we have the power to do something about it. I don't want to be the embarrassment of the galaxy, to have had the power to deflect an asteroid, and then not, and end up going extinct.
I despise the Lottery. There's less chance of you becoming a millionaire than there is of getting hit on the head by a passing asteroid.
Sooner or later, we will face a catastrophic threat from space. Of all the possible threats, only a gigantic asteroid hit can destroy the entire planet. If we prepare now, we better our odds of survival. The dinosaurs never knew what hit them.
There's no accepted global policy on what to do about asteroid impacts.
The chances that your tombstone will read 'Killed by Asteroid' are about the same as they'd be for 'Killed in Airplane Crash.'
If the Earth gets hit by an asteroid, it's game over. It's control-alt-delete for civilization.
What if an asteroid were to strike planet Earth? What could we possibly do to prevent it? However many guys we have working on this problem, it can't possibly be enough.