Dangerous asteroids

Q: How do NASA scientists find dangerous asteroids?

NASA has funded a number of searches to find dangerous near-earth asteroids. The basic idea is that astronomers use telescopes and cameras with a very large field of view so that they can search as much of the sky as possible. In repeated images, the asteroids can be seen to move relative to the much more distant stars.

These searches take many years and continue with larger and larger telescopes in order to find smaller and smaller asteroids. NASA is also using an infrared space telescope called called WISE.

Q: If scientists find a dangerous asteroid, what can we do about it?

There is very little we could do about it immediately, but as long as we had many years warning, there is reason to be hopeful. The best idea would be to change the asteroid's orbit slightly so that it missed the Earth. Possibly we could hit it with a very high speed spacecraft, or use a nuclear explosion. There are many other ideas.

-John Gizis