"Fareed Zakaria GPS," Sundays at 10 a.m. and 1 p.m. ET on CNN

Fareed speaks with the Frederick P. Rose director of the Hayden Planetarium, astrophysicist Neil deGrasse Tyson, about the implications of the meteor that exploded over the Ural Mountains last month. To see this or other interviews, download the show at iTunes.



The laws of math are that the probability is one of these things will hit...

Globally, what deeply concerns you is the asteroid strong enough so you have to restart civilization. And then, at another level, you risk extinction. Fortunately, those are large and we have a plan in place. NASA has a plan in place to detect and map and track every single asteroid that’s large enough to disrupt civilization. The one that exploded over Russia was not large enough to disrupt civilization. And so they’re dangerous and they'll hurt and they can kill, but the fact that we can’t track them is not as bad as not being able to track the big ones that could really destroy us. So once you know where they are, your next question would be, perhaps, do we have a plan to do something about it?

And the answer is no. It's all just on paper how to do it.

What would be the plan? Would it be some kind of military...?

Yes...

You’d shoot a missile to shatter it in outer space and...

Yes, that’s the macho solution is you pull one of your missiles out of the silo that have been sitting there doing nothing since the Cold War and you blow the sucker out of the sky. The problem is, I mean, 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.

Because the space ship has a kind of gravitational pull...

Exactly. They want to draw toward each other, but if you don't let that happen and you constantly yank the space ship away ever so slightly, then the asteroid will chase the space ship ever so slightly. And that's all you need if you get it early enough, because the tiniest change in your orbit early can completely avoid the target. Now, of course, it's there to harm you another day. But if you get really good at this, then you can have a protection system for the Earth that will prevent humans from going extinct.

Now, is it fair to say that we don't need any innovation in physics or even in engineering? We know how to do this. The question is the will and the resources to implement a plan like that.

Yes, I mean we use ordinary physics to know how to make this work, physics and engineering, of course, because you've got to make the hardware to enable it. And the price is not even all that expensive given other activities that humans have undertaken. The problem is the asteroid that we might find that will one day hit us. You want to get it early – when do we start concerning ourselves with a budget to handle it? If it’s going to come in 100 years, what do you say? Ah, let our descendants worry about that in their Congress. You know, 88 percent of Congress faces reelection every two years…And so that's not a long enough time scale to match the time scales that matter for our survival. Plus, if an asteroid is going to strike somewhere else in the world, is it NASA that's going to take care of that? So what you really want, I think, is a world organization, maybe every country chips in, in proportion to their GDP, something sensible like that. And then there's a pot of money. And whoever has the space faring resources at the time it's necessary…would then tap into that money and then you save the Earth. And I think that's a reasonable path.