Science Friday - If An Asteroid Were Headed For Earth, Would We Be Ready?

Episode Date: September 17, 2025

You might remember news reporting from earlier this year that a 180-foot asteroid had about a 3% chance of hitting Earth in 2032. And if it did, it would unleash energy equivalent to hundreds of nuclear bombs. After further observations, astronomers revised that probability way down, to close to zero. So what is our current capability to spot Earthbound asteroids? And how are governments preparing to communicate and respond to a potential impact on a populated area?Joining Host Ira Flatow with some of the answers are Kelly Fast, from NASA's Planetary Defense Coordination Office, and Leviticus “L.A.” Lewis, former FEMA liaison for that office.Guests: Dr. Kelly Fast is the acting planetary defense officer in NASA’s Planetary Defense Coordination Office, based in Laurel, Maryland.Leviticus “L.A.” Lewis is a former FEMA liaison to the NASA Planetary Defense Coordination Office.Transcripts for each episode are available within 1-3 days at sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Hi, this is Ira Flato, and you're listening to Science Friday. Today on the show, what disaster plans are in place in case a large asteroid is on track to hit a populated area on Earth? It was a lot to wrestle with because you have to take into account all this other risk with just taking action with an asteroid. You might remember a news item from the beginning of the year that felt like it was ripped from the sci-fi movie headlines. An asteroid about 180 feet long had about a 3% chance of hitting Earth in eight years, and if it did, it would unleash 500 times the amount of energy of the nuclear bombs dropped on Hiroshima and Nagasaki. But after further observations, astronomers revised that probability down, way down to close to zero. So what is our current capability to spot Earthbound asteroids, and how would governments

prepare citizens, their citizens, for an impact on a populated area. Here with some of the answers are Dr. Kelly Fast, acting planetary defense officer at NASA's Planetary Defense Coordination Office, based in Washington, and Leviticus L.A. Lewis, former female liaison for that office based in Vienna, Virginia. Welcome both of you to Science Friday. Thank you, Ira. Thank you. It's great to be here. Nice to have you both. Kelly, let me begin with you, because it's an like you had a busy start to the year. Can you take us back to when you heard about that asteroid, what your reaction was? Yes, it was a busy start to the year. At the end of December, we heard that an asteroid had been discovered that posed a very small chance of impact in 2032. And that's not

unusual. This can happen maybe a couple of times a year where something is discovered like that. and with more observations, it's found that, no, it's going to safely pass by. But in this case, it was apparent that this is going to hang around a little longer before we know for sure one way or another. And so it was an interesting process in January as more observations were taken to help try to narrow down in 2032, where exactly it was going to go. The worldwide capabilities, you know, both at NASA and around the world have, have, come so far over the years. One of the Atlas telescopes of the University of Hawaii that was located down in Chile discovered this asteroid 2024 YR4. So here we have these discoveries popping up, you know, more than we had before at a much higher rate than before, getting more of a heads

up on what could be coming our way. Is there a size, though, a size limit? It has to be a big enough kind of asteroid that you can spot it. I mean, what about the smaller ones? Well, exactly. In terms of the size, it just depends because the small ones we can spot too. If they're close, we can spot the large ones, you know, much further away. And so it just all depends. And this asteroid 24 wire4 has passed through the inner solar system before. But we play this game of tag around the sun. And the earth just hasn't been at the right spot previously. And so that was important there at the end of 2024 where things lined up just. just right where it was actually a fairly bright object and then it raced away and became faint fairly quickly. So sometimes it truly just depends. And that's why the search for asteroids, it's not something that can happen overnight. It does take years. You have to wait for the solar system to bring the asteroids around the sun to us. But as our capabilities are better, we can spot smaller ones further and further away. But we still have to, you know, wait for the

solar system to bring them to us as well. You know, our popular culture is filled with films about what would happen if we found an asteroid headed in our direction? Would we destroy it? What would we do these days if we found one? Didn't we have a mission to an asteroid to sort of nudge it out of the way? We indeed did. We had a demonstration mission to test one method for deflecting an asteroid, should we ever need it in the future? It was NASA's double asteroid redirection test or DART. And it was a successful test of impacting a spacecraft into an asteroid

and actually changing its motion in space. And so that kind of gave us a tool in the toolbox. And the other mission aspect is also reconnaissance. As you probably saw with the DART mission, the asteroid that it impacted, we didn't get a good look at it until right before impact. can you imagine how valuable it would be if there was an asteroid that posed an impact threat to Earth and to actually send a mission out to it and study its properties, and then if we needed to deflect it to be able to have that information

to really design an effective deflection mission. So again, having that time, that's why we want to find the asteroids well ahead of time, to have those options. And L.A., you guys really, you practice this stuff. you'll have asteroid kind of war games, right? Yes, yes. We try not to use the war games, as you can imagine in my business. Some people get concerned about saying war games,

but yes, we've had a series of exercises since 2013 by my NASA colleagues, being my Homeland Security leadership. You know, we're very familiar with space weather, but the area of planetary defense and asteroid impact, like you said, Ira, it was, you know, it's in movies and, stuff. And I don't think people took it as seriously as before when we started this effort. Is it really like a game, a computer simulation where you play one role and you get like a sealed envelope and you go from there? We started doing some of those techniques earlier, but the first

couple of exercises were all tabletop exercises, but I wanted to challenge the federal emergency response at your agency. So the first couple of exercises, we had short warning times, you know, six months or less where that would require everybody to pay attention and start doing the required action, but also what's the public communications for that. If we show up a hurricane charge, people would get that. But if we started showing them information from a possible asteroid impact, that would be unfamiliar to a lot of the American public. And we kind of consider a win, not an if situation. Well, how do you prepare the public for this?

And is it part of your simulation that you have to convince people who are in the decision process government people to talk to the public or get them ready? I think it's sort of a combination of both of those things, Ira, from USGS, from NASA, from NOAA, from all the other agencies that would participate. The key thing that I think is just give out as much information, be as truthful as possible, get it out as soon as possible, and show yourselves as the authority. You know, because other people will join them. They'll have their own scientific theories.

They'll say we're all wrong. It's going to impact here and not there. We made a lot of progress. My project that I was working on before I retired this past December was actually getting down and specific as what the actual notification process would be here in the U.S. with regard to, you know, going down from the whole movie scenario thing, the discovery. And we got to do some of this earlier, as Kelly said, with 2024 YR4. And then at one time, we actually had a community volunteer to be the quote-unquote victim of an asteroid impact.

And that was Winston-Salem, North Carolina. We did a joint exercise within all their firefighters and emergency management personnel. We were on a joint conference and we kind of did it like we were actually going to respond to it. But we also had an incident where we had somebody actually come on the Internet and present a whole entire counter to what we were presenting just to see how people react and kind of deal, how to deal with getting that false information or, if it's a fake news, that people are going to do something because we're going to have people that. they're going to deny this has happened. And we're all Americans, you know, some Americans tell us to get lost, even when we tell them there's an actual hurricane. And they can see it on the news.

They're going to stay home. So there are all kind of complications that we wanted to start working into the actual exercise. That's really interesting to hear that you had an actual simulation on the ground there. Kelly, let's talk about you were at the Planetary Defense Conference in South Africa earlier this year, where they were exploring a simulation. where an asteroid was on track to hit Johannesburg, and they had a very difficult choice to make.

Bring us into that room. What were the possible scenarios you were talking about? Right, and ultimately it was actually a little further north there in Southern Africa where the impact could be, but it was discussed. If you were to divert the asteroid one way, the goal would be to divert it off the Earth altogether, other. But as you try to divert the asteroid off the earth, in the future, you'd want to make sure that

it actually passes the earth. If it doesn't, then what is affected? Now, if you diverted the asteroid one way, it turns out you would end up over the ocean or over Antarctica and then eventually off the earth. So the risk was not so high to divert in that direction, but the other direction, you were diverting across a lot of the continent of Africa, a lot of, and also Europe, before you could actually divert the asteroid off the earth. But it was easier to divert in that direction. So it was a lot to wrestle with because you have to take into account all this other risk with just taking action with an asteroid. It's not necessarily simple and straightforward. And also you brought up earlier the Dart mission, something like that on its own isn't necessarily the solution because it might take multiple kinetic impactors to divert an asteroid or it might need another technique. We always talk about the Hollywood technique, but there actually are studies done. on how a nuclear deflection might take place. There's other techniques, ion beam,

but it really depends on the scenario, the lead time and the size of the asteroid. And at the Planetary Defense Conference, they were wrestling with this, with the deflection and how many missions might be needed to do it and how to get it all the way off the earth and whether you're putting other areas on the Earth

at risk as you're doing it. One of the other things we were wrestled with as emergency responders is how would you deal with transnational migrations because you have to do large-scale evacuations that might be international. So it's a lot more complicated. So that's why the value of the exercises is important to go through. Well, does the exercise actually take into effect all the politics involved in getting all those international agencies and governments together to figure out what to do? I think we try to acknowledge it, but we definitely don't try to solve it in our exercises, but it's good for us to go through it. One of the things I always like to tell my science

colleagues, and believe me, I am a strong science advocate. But, you know, one of the bottom lines is that we have to consider that, you know, we're dealing with fellow human beings, with fellow citizens. But the decision to actually do something is not entirely a science decision, in my opinion. It's a political decision. Yeah, and that sounds a little more difficult. It does seem so straightforward in the movies, maybe with one scientist out there warning everybody, but it's a whole community pulling together the technical information,

but then we're just bringers of the information, and we have some of the options for response when it comes to space. Emergency management has it when it comes to the ground. Now, the nice thing is over the past decade, there are collaborations in place that will hopefully help with that decision, There's two UN recommended collaborations, the International Asteroid Warning Network, which is observers and modelers around the world, and NASA actually leads that. And the Space Mission Planning Advisory Group, that's chaired by the European Space Agency. And that is the forum for the world's

space agencies and space offices to come together and collaborate on a response to a potential asteroid impact threat. And so even though ultimately it's individual, it's individual, nations that would fund any type of response. We already have this collaboration in place to provide mission options. So that's also very valuable. We have to take a quick break, but don't go away. More on this when we come back. Bad things happen, and we should be prepared as best we can to contribute to being ready for this.

I know there's work on an upcoming satellite called Neo Surveyor. specifically that would look for planet-threatening asteroids. Is that right? How far is that development going? Right. That development is underway. Neo-surveyor is being developed to really speed things up in terms of finding the asteroids that could potentially pose an impact threat to Earth.

And Neo-surveyor will be surveying along Earth's orbit where the asteroids that pose the greatest threat to Earth be able to survey closer to the Earth. be able to survey closer to the direction of the sun than is possible from the ground and also looking in the infrared, seeing the heat signatures from asteroids, and not being so sensitive to the amount of light that they're reflecting, like the telescopes on the ground, picking up their heat signatures, getting a better idea of their sizes. And so Neo-surveyor in concert with the telescopes on the ground,

that's going to really speed things up in terms of finding potential threats to Earth. And for us at NASA for addressing a tasking that, Congress gave us many years ago to inventory asteroids 140 meters and larger that could pose a hazard to Earth. And though all along, we're trying to pick up asteroids of any size that could pose a hazard, anything we find, get it in the catalog, and be able to check off, okay, that's not the one we're worried about. Let's keep looking.

Right. Well, NASA has recently just cut a lot of space budgeting, a lot of science budgeting, specifically, for example, the return sample mission from Mars, other kinds of science that is not human-oriented. How do we know that this neo-surveyor is not going to be axed also? Well, the administration has continued to say that planetary defense is a priority and that protecting the planets a priority. And so things continue with the neosurveyor spacecraft.

So working ahead to meeting that goal that Congress has set for us. And now that you say that, you have to continue to do this, how surreal is it to do this work? I mean, you sit in these simulations. You talk about potentially the end of the world or the major destruction of a city. L.A., how surreal is this? Well, Ira, that is the best question because I never thought, you know, when I was a kid, I'm the Apollo era kids, so, you know, I watched all the Apollo missions, and, you know, for a while, every kid wanted to be an astronaut. So for me, I'm a retired naval officer to actually do something that's concerning protecting the entire planet, but also being practical about, yeah, you know, bad things happen.

And we should be prepared as best we can as citizens to contribute to being ready for this. But I have to say it is something that I never in my wildest dreams thought that I'd be working with NASA. and sitting down with scientists like Kelly Fass and actually listening to the things. I used to talk about and dream about it as a kid and actually be in a position where I can actually do something about it. Kelly? Oh, I agree with L.A. In fact, he and I are both big Star Trek fans and sci-fi geeks.

But then in a way, you feel like you're living it in this job. But it's also sobering because you're rooted in reality. but you're kind of informed by that cool sci-fi side of things. But to also have science that can be applied to people's everyday lives, you know, like space weather, like weather, like planetary defense. It's just a privilege to be involved in that and a heavy responsibility too, but it's encouraging because, you know, it isn't just about like, you know, the one scientist in the movie who's running around trying to handle everything.

there's a fantastic team of people and then our collaborations with like FEMA. It all made that very fulfilling to be able to be involved in such an activity. Well, we have run out of time, but I can't think of a better way to end it than you guys talking about it that way. Dr. Kelly Fast, acting planetary defense officer at NASA, and Leviticus L.A. Lewis, former FEMA liaison to the planetary defense. Defense Office. Thank you both for taking time to be with us today. Thank you, Iris. It's been great. Yes, thanks for having us, Ira. You're welcome. Hey, thanks for listening. This episode was produced by D. Petersmith. See you next time. I'm Ira Flato.