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IRA FLATOW, host:

You're listening to TALK OF THE NATION: SCIENCE FRIDAY. I'm Ira Flatow.

Up next, the topic for you, Bruce Willis fans - the search for killer asteroids. Scanning the skies for asteroids that may be on a collision course with Earth. Astronomers think they may have actually found one with our name on it. It will fly close by the Earth in 2029 and then, it may be back in 2036, possibly on target for our planet.

So for the rest of the hour, we're going to talk about the asteroid threat. What can we do to deflect Earth-bound asteroids? Why the time to act is now, decades before any of it really threatens us - any threat is imminent.

Our number 1-800-989-8255. 1-800-989-TALK.

David Morrison is a senior scientist at the NASA Astrobiology Institute. That's at the Ames Research Center in Moffett Field, California. He joins us from his office today. Welcome back to the program, Dr. Morrison.

Dr. DAVID MORRISON (NASA Astrobiology Institute): Thanks, Ira. It's good to be here.

FLATOW: You know, we've talked many times about close encounters with asteroids and now it seems like you got a real live one.

Dr. MORRISON: We have been carrying out this Space Guard Survey for more than 10 years and so we've kind of taken the subject from the esoteric statistical to real objects. And this one asteroid, Apophis, although it really is very unlikely to hit us, it's a specific example we can focus on and that's kind of the way it's going now. As the survey finds objects, we've followed them in particular and drop the old statistical stuff.

FLATOW: Mm-hmm. So this one is supposed to come by first in the year 2029, then -

Dr. MORRISON: On April 13th, the Friday.

FLATOW: We got the exact - Friday the 13th in 2029.

Dr. MORRISON: Yes, sir.

FLATOW: Keep going. This is getting better.

Dr. MORRISON: Well, as you explained, as it goes past the Earth it will be so close it will be visible to the naked eye. It will be well within the range of our - synchronous the orbiting satellites. And the Earth's gravity will bend the orbit and it will really leave the Earth on quite a different orbit.

And chances are certainly high that that other orbit will never bring it back close to the planet. But there are certain exit orbits and we can't be absolutely sure yet what it's going to do - that do come back and get us seven years later.

FLATOW: And what would the chances be, one in what for it coming back and hitting the Earth?

Dr. MORRISON: The problem is the fact that we don't have an accurate enough orbit. The asteroid knows where it's going. It's only in Hollywood that asteroids capriciously change their orbit. But we don't know, and as time goes on, our information gets better. Today, it's down at the level of about one in 45,000 and we expect, with some more observations and a more precise orbit, we can eliminate these risks entirely. Meanwhile, it's been very interesting.

FLATOW: Mm-hmm. Now whose responsibility is it then to take care of eliminating this asteroid?

Dr. MORRISON: Well, it's not Bruce Willis. The - in fact, in some ways, it's not completely clear. Congress has given NASA the job of surveying and tracking these objects, projecting their orbits forward, attempting basically to find the next killer asteroid before it hits us.

But if and when we do find that asteroid with our name on it, it's not entirely clear what will be the next step. We have, at least in principle, the capability of deflecting an asteroid but we have not tested any actual hardware technology for doing that.

FLATOW: Mm-hmm. So it could be a U.N. thing, then, possibly with some other country, in cooperation with them?

Dr. MORRISON: If there's any problem that affects the whole world, it's just not a U.S. problem, and so something like the U.N. undoubtedly will be involved in a decision making. But right now, the U.S. is the only country, I think, that has the space capability to actually go out there and do the deflection.

FLATOW: Let's talk about what you would do. You mentioned Bruce Willis in a movie, didn't they blew up the asteroid in that movie, right?

Dr. MORRISON: That's probably not a good idea. You sort of change it in to many impacts instead of one. The preferred solution, again in principle, we don't know the details, is to give the asteroid a relatively gentle push and change its orbit. And that only works if we have long lead-time. Given decades of warning, we could probably go out and do that, and give it a gentle enough push that we wouldn't disrupt it but also it would miss the Earth entirely. This is the only natural hazard that can be eliminated entirely.

FLATOW: 1-800-989-8255 is our number. It can be eliminated - the hazard -entirely, if we give it enough lead-time.

Dr. MORRISON: That's right.

FLATOW: Would we wait for it to come by that first time in, you know, Friday the 13th and then, move it or do we go out after it?

Dr. MORRISON: For Apophis, it's much easier to deflect it if we do it early before that Friday the 13th. But there are uncertainties and you certainly don't want to go out and push it in a way that might actually put it on to a collision orbit when it really was just going to pass nearby.

So it's tricky making those judgments.

FLATOW: So you want to define that orbit. You want to refine and define it more before you do anything.

Dr. MORRISON: That's right, and that's sort of what these surveys do. We will find the objects decades in advance, but now we're beginning to realize that just finding them and getting an approximately orbit may not be enough. And so we have to use things like Sebo radar, maybe even send a spacecraft out, a little one, to put a radar reflector on it so that we can make sure we have the orbit accurately enough to know whether we should take action.

FLATOW: Tyler(ph) in Mississippi. Hi, welcome to Science Friday.

TYLER (Caller): Thanks. I was wondering: Is there any possibility of knowing where this originates or anything like that, or do you have any way of knowing that type of thing or…?

FLATOW: Where did it come from, yeah.

Dr. MORRISON: Well we sort of know. The near-Earth asteroids, these ones whose orbits bring them close to the Earth and across the Earth's orbit, have not been there forever. That is a population of near-Earth asteroids, which is ultimately derived from the main asteroid belt between Mars and Jupiter. That's where most of the objects reside, and occasionally one gets knocked into this Earth-crossing orbit.

So we're dealing with a population that originated somewhere in the asteroid belt, but we no longer know well, because the orbits have been shuffled so that we can't specifically say where it came from.

FLATOW: Now how big is this asteroid, and how good is your equipment that use now to detect this one or even smaller ones?

Dr. MORRISON: This one, which is about 300 meters across, so it's the size of a stadium or even larger, the size of the Washington Mall, you know, it would definitely hurt if it hit. But it is one of those products of the current Spaceguard Survey. And the Spaceguard Survey focuses on asteroids larger that one kilometer, but it certainly is picking up a lot of smaller ones, and the shift is going to go to those smaller ones as we complete the current survey for the big ones.

FLATOW: Do you have the money to increase your power to find the smaller ones?

Dr. MORRISON: No.

(Soundbite of laughter)

FLATOW: So there's an asteroid out there with our name on it, possibly, and maybe hundreds of them that we haven't seen because we don't have the power to see them, and we don't have the money to find them.

Dr. MORRISON: Well, we haven't really tried yet, but there are plans right now for some ground-based telescopes and some space-based systems that certainly have the capability to carry the survey to much smaller objects. But right now, there's no NASA budget to carry on with that.

Some of the telescopes may be build, like a big one in Chile, anyway, but it will cost some money to pull the asteroid data out of the astrophysical observations that are being made.

FLATOW: Now, why would this be a NASA budget? I mean, if this is national security, why wouldn't the military or some other protector of our country be involved and seeing this is not, you know, this is not a project to observe something. This is a project to deflect something.

Dr. MORRISON: Well, this is a project to observe something, and that is a responsibility that the Congress has assigned to NASA, and I think that's perfectly reasonable. We have the capability. If it ever comes to a deflection, then it will be a different issue.

FLATOW: But so far, we don't have the money to do what we need to do, or NASA doesn't give you the money.

Dr. MORRISON: We've been extraordinarily with this Spaceguard Survey. What I'm talking about now is a change to bigger telescopes to search for smaller objects, and that has not been implemented yet.

FLATOW: But is it on the drawing boards?

Dr. MORRISON: We know how to do it, but you asked about money.

FLATOW: Yeah, money talks.

Dr. MORRISON: It's not quite there yet.

FLATOW: Who do you have to convince?

Dr. MORRISON: I don't know. You, Ira, probably know the detailed workings of Washington much better than I do.

(Soundbite of laughter)

FLATOW: That's why we're here in New York, because we can't figure that out, but we know money talks in Washington. 1-800-989-8255. Let's go to Jack(ph) in Tucson. Hi, Jack.

JACK (Caller): Hi, I'm driving in my car. I hope you can get this question real quick. I'm just wondering if this asteroid is large enough to perturb the orbit of the planet. It certainly is large enough to perturb the orbit of the moon, and I was wondering if there's been any calculations on what an asteroid of this nature might do to this orbit.

Dr. MORRISON: Well that's a good question, and you raise a point that's worth making, that these asteroids are so tiny with respect to the Earth or the moon that the impact has no effect on the planet as a whole, not its orbit, not its spin rate, not its tip of its axis, not its magnetic field.

You know, the planet really couldn't care less. But these little asteroids are still capable of doing a terrible damage where they hit and even affecting the environment over the whole planet. But as a geophysical body, the Earth and the moon really couldn't care.

FLATOW: Talking with David Morrison. Dr. Morrison, lay out a plan. let's say you have a blank check. I'm going to give you that hypothetical blank check. You've got the money you need. What plan would you do to help us better detect and dissuade these asteroids from hitting us?

Dr. MORRISON: Well, I can speculate, but this is certainly not an authoritative statement. I think that we would probably next expand the survey. If you can't find the objects, all the other business about deflecting them is pointless. You have to find them, and you have to give yourself decades of warning. And we could do that pretty well with two big telescopes under construction, the Pan-STARRS telescope in Hawaii and the thing called the LSST, the Large Survey Telescope, in Chile.

And so that would certainly be the next step. Then the questions that arise are: Should we go ahead and start developing technology? The Europeans' answer is yes. They are developing a mission called Don Quixote in which they will hit an asteroid at high speed with a ballistic rocket and measure the effect on the orbit of the asteroid.

So there is a concrete step, and then we'll just have to see where it goes from there.

FLATOW: And when is that launch happening?

Dr. MORRISON: They aren't fully committed yet but probably launch in about five years.

FLATOW: Talking about asteroids this hour on TALK OF THE NATION's SCIENCE FRIDAY from NPR News with David Morrison, who is Ames Research Center in Moffett Field, senior scientist at the Astrobiology Institute at NASA there. 1-800-989-8255. Let's go to John(ph) in Gainesville, Florida. Hi, John.

JOHN (Caller): Hi. Hi, Dr. Morrison. I wondered if you were familiar with a proposal to use lasers to fire at incoming asteroids or comets and ablate enough of the surface above escape velocity that it would actually provide a gentle push to deflect their orbits?

Dr. MORRISON: Yes, John. There are some very interesting ideas. I think it's probably not conceivable that you could do this with a laser on the ground, but a big laser in space that could actually fly to the asteroid and then zap it might be one way to do it. Hitting it with a spacecraft is one way. Using a nuclear explosive, building a great, big, solar sail type of thing and reflecting sunlight onto it, all of these are ideas that have been suggested. None has been developed.

JOHN: The particular proposal I saw was on a space.com Web site, attributed to Langley Research Center, and the idea was to put a laser base on the moon, and by shooting the beam from the moon rather than flying to the asteroid, you save months of transit time and can actually get started sooner.

I also wanted to ask you whether the Spaceguard is only looking in the plane of the ecliptic, or if it's looking in the whole celestial sphere for comets, which might come from way out of the ecliptic?

Dr. MORRISON: Spaceguard covers the whole sky because what we're trying to do is find these near-Earth asteroids not on their final plunge in toward Earth but some previous time because before they hit, they'll come by hundreds, thousands of times.

It also picked up comets, but frankly comets we don't know how to deal with because they don't come by repeatedly, and you can't find them years in advance, and so while a comet hit is very unlikely, it probably is nothing we could do anything about.

FLATOW: How far away, ideally, if you can pinpoint the orbit and you know one is going to be threatening us, how far away do you want to deal with it, you know, outside of our solar system, outside of our - you know, what range? How many distances of our solar system away?

Dr. MORRISON: We can't find those objects, we can't zap them. The ones really coming from a long way out, I don't think we're in any position to discuss. For the asteroid, these near-Earth asteroids, it's better not to ask how far away in distance but how far away in time, and you'd want to start your deflection process at least 20 years before it hit.

FLATOW: Oh really? So we have 10 years to get going on this one because if it's going to be coming around in 30 years from now?

Dr. MORRISON: Yeah, but we don't think that it's a problem. If we can eliminate it for sure as a problem, then there's no reason to talk about spending a lot of money to try to deflect it. There are actually a few other asteroids on the list, and all of these are available on the Internet for anybody to look at, that have also a very, very small chance of impact based on current uncertainties in the orbit, and over time, we'll refine all those.

FLATOW: Do you think it's going to take - you know, we tend to work in a society that needs alarm bells going off. Is this a big enough alarm bell to get this moving a little faster?

Dr. MORRISON: Well that's a good question, and I'm no expert on how societies react. I think it's probably true that if we were hit by even a very small one, that would be a real wake-up call. I don't necessarily think that's necessary for further action.

FLATOW: But you don't want to be a dinosaur in this one.

Dr. MORRISON: We do not. The dinosaurs didn't have an inkling that it was coming. And this 10-mile object hit and just devastated all the bio(unintelligible) of Earth. Not only did all the dinosaurs go extinct, but even most of the mammals and most of everything did. Right now, in a sense we're still vulnerable like because the good chances are that the next object that'll hit us, while not that big, will not be predicted unless we carry out this advanced survey.

FLATOW: All right. I think you've alerted us, the Paul Revere of asteroid collisions. Dr. Morrison, thank you for taking time to be with us.

Dr. MORRISON: My pleasure.

FLATOW: David Morrison, senior scientist at the NASA Astrobiology Institute. That's at the NASA Ames Research Center in Moffett Field, California.

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