I heard on TV that the odds of waking up to a day in which an asteroid will strike the earth are too short for comfort: 1 out of 20,000. Are the odds this short?

I watched this program again. This time I spotted the statement at the end of it which mentioned that some facts were changed for dramatic effect. This seems to be a desperate measure to get funding for the study of asteroids, given that the program mentioned that only 60% of the asteroid pool has been studied to determined which asteroids are likely to hit earth.

You'd have to define a few parameters to make that statement meaningful. Something like 100 tons of asteroid material reaches the earth every day.

So what size are we talking about? It takes a pretty large one to reach the ground before disintegrating, but even one that disintegrates can make a large fireball in the sky (as in Kusaie in 1994) or even produce and explosion heard over 1,000 km away, an explosion hundreds of times Hiroshima's, and wipe out thousands of square miles of forest (Tunguska, 1908).

Here's a site on impact frequency of different sized objects from the American Museum of Natural History.

I'm relieved that the link stated that the biggest asteroids, the ones most likely to do the most damage, have all been spotted. So I'll go back to worrying about the rat race instead.

I doubt they've all been spotted. Every few months, a new danger is discovered.

I think that very many small ones (1,000's at least) do disintegrate over earth daily, but I hope that scientists are vigilant regarding the big ones (hopefully, 0 at most) heading for earth.

Even if a huge asteroid would a threat to earth, what can we do here to stop it? Does the government have anything that could blast it to pieces?