Is Earth destined for another extinction-level asteroid event? | The Excerpt
On a special episode (first released on October 2, 2024) of The Excerpt podcast: Hollywood has long been enamored with end-of-the-world science fiction where asteroids play the leading role. But the reality is that asteroids did in fact lead to the end of the non-avian dinosaur era sixty-six million years ago. Could it happen again? How at risk is mankind and what steps are scientists taking to avert a potentially catastrophic collision? Robin George Andrews, author of "How to Kill an Asteroid," joins The Excerpt to discuss how scientists are working to literally save the planet.
Hit play on the player below to hear the podcast and follow along with the transcript beneath it. This transcript was automatically generated, and then edited for clarity in its current form. There may be some differences between the audio and the text.
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Dana Taylor:
Hello, and welcome to The Excerpt. I'm Dana Taylor. Today is Wednesday, October 2nd, 2024, and this is a special episode of The Excerpt.
It's called Apophis. The asteroid has a tiny chance of hitting Earth on Friday the 13th in April of 2029. That chance depends on it being hit by another asteroid or some other object in space at just the right angle to redirect it and send it our way. To date, scientists haven't zeroed in on any imminent asteroid threats, you know the kind that wiped out dinosaurs, but does that mean definitively that there couldn't be more hurtling towards Earth? How at-risk is mankind, and what steps are scientists taking to avert a catastrophic collision, and is it possible or even a good idea to attempt to rearrange things in space?
Joining us now to discuss how scientists are working to literally save the planet is scientist and author, Robin George Andrews. His new book, How to Kill an Asteroid, is out now. Thanks for being on The Excerpt, Robin.
Robin George Andrews:
Hey, thanks so much for having me.
Dana Taylor:
In your book, you vividly describe the impact of a football-field-sized asteroid like Apophis hitting Earth. City-killers, asteroids large enough to wipe out an entire metropolitan area, are terrifying. What's the actual risk of one of these asteroids hitting Earth?
Robin George Andrews:
So yes, asteroids that we often think of as threatening the planet are these sort of planet killer-sized asteroids, which are several miles wide, crash into the planet, wipe everyone out, the sort of thing that happened to the dinosaurs. But actually the threat, as you mentioned, are these city-killer asteroids.
Now, these are very, very small, tens to hundreds of meters, so a few hundred feet, and there are about 25,000 of them in near-Earth orbits. They orbit the sun sort of relatively close to the Earth. The problem is, scientists have only found just under half of those, so those ones aren't a threat. The orbits aren't coming in contact with Earth in the next century or much longer. But we don't know what the others are doing, so until we find those and find out what they're doing, we don't really know what the day-to-day threat is. So, keep paying your mortgage, but just hope the scientists will speed this detection quest up a little bit.
Dana Taylor:
So, you're saying that an asteroid large enough to wipe out life on Earth as it did with the dinosaurs, that's not a valid fear, really to focus on these smaller, more frequent asteroid strikes?
Robin George Andrews:
That's right. Within a human lifetime or several human lifetimes, a planet-killer is not something that we should worry about. We've found pretty much all of the ones that orbit around Earth, but these city-killers are stealthy. They're very small, they can come out of nowhere, so yeah, they're the things that, again, not a day-to-day worry. But if you live to 100, there's something like a one in 200 chance of a city-killer finding its way towards Earth. Could land in the ocean, could be fine, but could hit a city, so how lucky do we feel, really?
Dana Taylor:
Two years ago, NASA's Double Asteroid Redirection Test, or DART mission, successfully altered the trajectory of an asteroid. How did they do it and how were they able to keep it from bumping into another asteroid, potentially changing its trajectory?
Robin George Andrews:
So cool, this mission. NASA have long wanted to test a planetary defense technique, and in this case, it was hitting an asteroid really hard with a spacecraft to change its trajectory. Now, they say you couldn't do that with any asteroid. If it was just on its own, you could deflect it onto a dangerous course, so what they did is they picked a binary asteroid system. There's a larger asteroid called Didymos, and around that, like a moon, is the one called Dimorphos. They reasoned that if they hit Dimorphos, the moon-like asteroid, it would change its orbit around the bigger one, but it wouldn't change their overall orbit around the sun, so it was a perfectly safe way to practice saving the world. It was pretty clever.
Dana Taylor:
You've said that asteroid impacts could be the one natural disaster we can prevent. The DART mission was a significant milestone. How do you see it shaping planetary defense strategies in the future? Is a global effort called for here?
Robin George Andrews:
It took a lot of work to get to the point where a space agency could even test this technique, but it's a very brute force technique. An asteroid's coming towards you, what do you do? You swat it away, but it requires an incredible amount of precision. You are hitting a relatively tiny target moving tens of thousands of miles an hour through space with another tiny target, and you have to hit it not too hard to stop it breaking apart, because that'd be like turning a cannonball into a shotgun pellet shot. You have to hit it just right. You have to kind of know what the structure of the asteroid is like before. So, it's not a simple matter of hitting it as hard as you can, but what it has done is inaugurate Earth's ability to defend itself from these city-killer asteroids. So, I think other space agencies are going to start practicing their own method of deflecting asteroids. I think China recently announced that they're going to do just that.
Dana Taylor:
Robin, can you give us some insight into the scientists leading the charge in asteroid defense?
Robin George Andrews:
They're not what you would think of as sort of typical scientists. I mean, I argue, there are no typical scientists in a way, but if you think of the most stereotypical image of a scientist sort of thing, they're not that at all. The leader of America's planetary defense efforts was heavily inspired by Star Trek, and his sort of second in command, she went to see the premiere of Star Wars in Hollywood in 1977. So, they are the sort of kids that didn't grow up who thought, "Hm, I want to do something really cool, something really gung-ho, sort of out there kind of science," but also, it just happens to be science that will make a difference to billions of people. So, they're very, very outgoing, very, very happy to chat, very, very exuberant, exhilarated about things. They just seem like they've never grown up, and as a result, we're all safer for it.
Dana Taylor:
SPACECAST 2020 made predictions about space defense initiatives. Can you share a bit about the history of SPACECAST 2020, how it came about, and a few of the predictions?
Robin George Andrews:
Yeah, so SPACECAST 2020 was a really interesting report that was commissioned essentially by the Air Force to try and work out what sort of threats that America might face in 2020 as seen from the perspective of someone in the late '80s, early '90s. And most of these documents produced by various members of the Air Force were talking about superiority against enemy nations, satellite warfare, things like that. But Lindley Johnson, who's now America's planetary defense officer, thought, "Well, wouldn't it be good if the Air Force could use its technology and its know-how to maybe stop asteroids crashing into the planet?" And it kind of foresaw that there would be an urgent need to do that, because if you wait long enough, an asteroid or comet is going to hit the Earth, and wouldn't it be nice to do something about that? It took a while, but that kind of effort to save the world from asteroids actually came to fruition. It only took several decades.
Dana Taylor:
NASA is currently working on this space-based Near-Earth Object Surveyor telescope. It's designed to track asteroids and comets. The target launch date is late 2027. What technological or scientific breakthroughs do you think are crucial to achieving the goal of not only tracking, but averting collision?
Robin George Andrews:
Near-Earth Surveyor is super cool. It's basically the closest we're going to have to a sort of asteroid scout, maybe even a sniper sort of thing. It's going to look in the infrared, and asteroids, like everything in space, glow in the infrared. It's like that kind of thermal imaging technology you see in a lot of films and things. And the problem with asteroids at the moment is that they are detected when sunlight reflects off them, which is good enough to kind of get a broad idea of the size and where they're going. But infrared can just see all these asteroids, even if they're illuminated by the sun's glare, if they're hidden like a match in front of a bonfire. It can immediately tell the size of the asteroid. It doesn't matter what it's made of. And basically, this is going to find almost all of the remaining city-killers in the Earth's orbit that ground-based telescopes haven't been able to find, so that's really incredible.
And with that, at the same time, scientists are developing extra technology to help work out how to deflect or destroy these asteroids. In fact, scientists in New Mexico recently tested a way of developing sort of like a simulated nuclear explosion in a lab. It's not dangerous at all, but they've used that to kind of see if they could irradiate an asteroid to sort of knock it back, and it turns out they can. So, we're living in good times in that sense.
Dana Taylor:
You mentioned films, and I was going to ask you about exactly that. If we were talking about a Hollywood movie, the scientists in the film would be discussing a nuclear option, and you're saying there is a real-life nuclear option being worked on here.
Robin George Andrews:
Yeah. In fact, for some scenarios, as our technology is currently, a nuclear explosive device, as they're known, or NETs, are probably the best option, because they deliver the most energy in the easiest and shortest amount of time. So, say you have a city-killer coming towards Earth, if we have less than 10 years, for example, or the asteroid is way bigger than that, and we do have more time, you can't just slam a spacecraft into it and knock it off course. It might not knock it off course in time. It might be too big. In that situation, what you'd want to do is actually get a spacecraft to fly basically itself to the asteroid, not drill a hole into it, but park nearby and detonate its nuclear explosive. And what that does is it irradiates the surface of the asteroid, one surface. The surface breaks apart, it turns into like a jet of debris, and that basically turns the asteroid into a rocket, pushing the asteroid off-course, and it'll do that more emphatically than a spacecraft crashing into it.
There are obviously problems with using nuclear warheads in space. It'll cause a lot of political tension. No one wants to see anything nuclear explosive being launched into the sky, so this would be a real emergency. But in the face of doing that or doing nothing, I'm presuming some country or countries in the world would rather opt for the nuclear option. But yeah, it's a real life option. It's just difficult to test.
Dana Taylor:
Private companies are becoming increasingly involved in space exploration. Recently, researchers in the Netherlands said that radio waves from Elon Musk's Starlink satellites are creating a roadblock to peering into space. What are the challenges or ethical considerations here that should be top of mind for governments and private corporations?
Robin George Andrews:
Yeah, the problem with this proliferation of satellites, primarily like Starlink satellites, is that they reflect a lot of sunlight at sunset, twilight hours? That's when ground-based telescopes really want to point towards a kind of region of the sun to try and find these potentially dangerous asteroids that we haven't spotted yet. So, it's like there's huge graffiti streaks across the sky, and it's impacting all kind of ground-based observatories.
Morally, you would hope that people that design these satellites, and it's not just Starlink satellites, it's any private company that launches them, we have to find ways to make them less reflective. Now, the technology to do that definitely exists, but it appears to me that these companies are more interested in just getting their satellites up there, worrying about the consequences later, but they're already impacting ground-based astronomy around the world. That also includes planetary defense efforts, so it seems a bit morally sketchy to me to just keep launching them without thinking about the consequences.
Dana Taylor:
Asteroids aren't the only potential threats lurking in space. Are there any additional dangers scientists are equally concerned about, and how prepared are we for those?
Robin George Andrews:
Scientists are not as concerned about comets as they are asteroids, for one good and one bad reason. The good reason is that comets spend most of their time way far away from Earth than asteroids. Most asteroids hang about in the Mars to Jupiter region, and the ones near Earth obviously hang about a bit closer. There's just loads of more asteroids, so we have to be concerned about those. So, we don't have to be worried about comets because the chance of a comet striking Earth is very low.
However, if one were found coming towards Earth, at this point, there's basically nothing we could do about it. They're just too big, way too fast. What's that line from Armageddon? I know it wasn't a comet, but, "You could just fire everything you can at her and it should smile and keep on going." That's basically true. So at the moment, that would be a huge problem, but there's no evidence that any comet is anywhere close to heading towards us, so it's not something we should really worry about. But once they've sorted out the asteroid problem, then they'll move on to comets.
Dana Taylor:
We know at least one devastating asteroid impact has happened before. Do you think the failure to act decisively on planetary defense now will inevitably lead to history repeating itself?
Robin George Andrews:
Oh, I hope not. See, that's the concern. I mean, the fact that something like DART, this deflection technique, is getting off the ground now, that's a good thing, but it's a matter of who's faster? It's a race against something that we don't really know about. Is there an asteroid heading towards us? Don't confidently know this yet. So, the hope is that things like Near Earth Surveyor, and there's another ground-based telescope that will find so many asteroids, called the Vera C. Rubin Observatory in Chile, that's coming online next year, actually.
The hope is that we find all the dangerous space rocks if they're there before one hits us, so it's good that all this is happening, but there is obviously a chance that we could get really unlucky and a city-killer asteroid could find its way to hitting a city before we've spotted it in time. The hope is that we've acted fast enough. And I have to say, on planetary defense, humanity is being a bit more proactive than it is for most global-scale emergencies, so I'm optimistic. It's more of a feel-good story at this point.
Dana Taylor:
I thoroughly enjoyed your book. It's called How to Kill an Asteroid. Robin, thank you so much for joining me on The Excerpt.
Robin George Andrews:
Thanks so much for having me.
Dana Taylor:
Thanks to our senior producers, Shannon Rae Green and Kaely Monahan, for their production assistance. Our executive producer is Laura Beatty. Let us know what you think of this episode by sending a note to podcasts@usatoday.com. Thanks for listening. I'm Dana Taylor. Taylor Wilson will be back tomorrow morning with another episode of The Excerpt.