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EPISODE TRANSCRIPTION (AUTO GENERATED)

Go get your coziest blanket, your favorite chair, a mug of something warm and delicious, And let's discuss existential threats to the human species. Because folks, it's time for us to have a lovely chat about the end of the world. Sooner or later, it's gonna happen. Not the end of the world. I mean, giant rocks.

A giant rock will come from nowhere. It will fall from the sky and it will smack our planet. It's impossible to say when. It's impossible to say how bad it's gonna be, but it will happen. It's a fact of life in the solar system.

Our planet is not alone here in the solar system. It's not even alone in its orbit. There are dozens, 100, thousands of asteroids and comets that wander the interplanetary depths. Most are harmless, minding their own business, following their own lonely trajectories, but some are threats. Some are deadly.

Some stray a little bit too close. These are what are known as the Near Earth Asteroids or NEA's. Although sometimes you might encounter an alternative term, NEO for Near Earth Object, which encompasses asteroids, potential comets, and, like meteoroids. Just like stuff that's too small to even be counted as an asteroid. So n e a n e o.

It's rocks in space that get too close. The International Astronomical Union's Minor Planet Center, which maintains a list of, and no points awarded for guessing this correctly, minor planets within the solar system has a running tally. At the time of recording of this episode, the center has recorded 34,152 asteroids with orbits that come within 0.05 astronomical units of the Earth. As a reminder, an AU, astronomical unit is the average distance between the Earth and the Sun. And so we're talking about less than 1 20th of that distance.

If a rock comes within that distance, it is classified as a potential threat as a near Earth object or near Earth asteroid. You take your pick. I don't care. You can call it whatever you want. Of all the bajillion, approximately, space rocks in the solar system, these are the ones we need to watch out for.

These are the ones that are most likely to hit us in the future. And it's happened before. The record of their violence is littered across the solar system. I mean, just look at the moon. We see the moon and it looks all pretty.

It's got all these cool craters. Where do you think those craters came from? They came from giant rocks smacking into the moon. Look at any airless world. Mars.

Mars has tons of craters. Mercury, tons of craters. Other asteroids, also tons of craters. There are craters everywhere. And the Earth was not spared.

We have our own history of violence, our own records too, but those records are difficult to find because the Earth constantly reshapes its surface. We have weathering. We have wind erosion, water erosion that erases slowly over time the evidence of any impacts. We have plate tectonics that over 100 of 1000000 of years completely re sculpts our surface and so it can just eat up, gobble up, bury any evidence of past craters. But, oh, yeah.

We've gotten hit a lot. How bad can it get? That's that other question. You know, we're going we're going to be exploring 2 questions in this episode. How often does it happen and how bad can it get?

How often does it happen is, like, basically all the time. How bad can it get? Well, just ask the dinosaurs how bad it can get. You know, there was that, you know, kind of serious extinction event 65000000 years ago, when an object a few miles across struck our planet off the coast of the Yucatan Peninsula? It was bad.

It was horrible. It there were tsunamis. There were firestorms across the world. Volcanoes triggered and went off. Material shot up halfway to the orbit of the moon and then came raining down in this molten hellfire.

The extinction event blocked out the sun for like 10000 years or something. The extinction event killed almost every single land species of animal greater than a 100 kilograms. That was big. Yeah. Some dinosaurs made it.

We call them the birds, and the birds, to be fair, are doing just fine. But that wasn't a fun day for their kind. So let's put some numbers on it. It can get really bad. Like, that's the worst is global extinction event, but presumably there are a lot of categories below that of not quite global catastrophes, but still really really nasty.

And then how often can all of this stuff happen? Well, like the big one, the big extinction event was 65000000 years ago. Is it really like 65000000 years between events? What do we got? Believe it or not, we have charts for these sorts of things because we're nerds.

And if you're debating what new art to put up in your living room, I've just I've got just the thing, which is this chart of impactor diameters, energies, and frequencies. That's a great conversation starter. In the literature, you will also find this other term. We already have NEOs and NEAs. You also have this term impactor, which is the object that is actually striking the earth.

And it's just a general catchall term for anything that hits us. And these run the gamut. So like the smallest ones that we need to actually care about or pay attention to, you know, like like meteors, showers, and all that. We see these all the time. It's just little grains of dust.

We don't care. When we start to care about things is around 3 to 4 meters across, around 10 to 15 feet. That's when there's actually something noticeable, actually something interesting. And it goes all the way up to the biggest ones like the kilometer scale impacts or sorry, kilometer scale impactors. Those are the really big ones.

And in recent memory, as in the past few 1000000000 years, those are the biggest ones to have struck the Earth. So there's our range from, yeah, a meter, a few meters to a kilometer or so. And at this small range, at the range of a few meters, you know, these rocks are coming in. They are hitting at tens of thousands of miles per hour or kilometers per hour. I'm gonna play fast and loose with my units here because, you know, it's it's big and fast.

That's all that matters. Sometimes there's a direct hit. Sometimes it's a grazing impact. Sometimes we're meeting head on. Sometimes the impactor is catching up with this.

So, you know, it changes like the speed and the angle, but we can get some rough numbers. When you have an object, a few meters across, you know, 10 ish, 20 ish feet across, when that hits our atmosphere and it translates its kinetic energy into heat and sound and fury and all that, we're talking a few kilotons worth of TNT. These happen every few years. We've actually recorded dozens of them in our atmospheric observations, and then that's about it. They just burst in the air and then they make a pretty show, and then that's it.

Around 10 meters across, that's an important threshold. 10 meters, 30 ish feet across. That's when you start to cross the threshold of impactors that when they detonate, when they go off in our atmosphere, we're talking 15 to 20 kilotons. That's roughly the equivalent of the nuclear weapons dropped on Hiroshima and Nagasaki. So that's all it takes is a rock, you know, 30 feet across.

That's not all that big. It's it's like smaller than a house. So a single rock smaller than a house hitting our atmosphere delivers the energy equivalent of our earliest nuclear weapons. We have recorded some of these. They happen roughly every 10 years, and they and they happen.

And then it goes up from there. So, there's one case, the the Chelyabinsk meteor. This entered our atmosphere in February of 2013. This rock was about 20 meters across, about 66 feet across. It exploded in our atmosphere, and the explosion had about 230 kilotons of energy behind it.

230 kilotons. That's 10, 15, 20 times greater than the Hiroshima bomb? One rock. Yeah. Yeah.

It gets it gets nasty. And it goes up from there. You know, just larger and larger rocks deliver more and more energy. Eventually, you get to the scale where your impactor isn't just going to blow up in the atmosphere. It's actually going to make its way all the way to the surface and impact to the surface and leave behind a crater.

And obviously, these are the ones that we really need to worry about because in atmospheric detonation, you know, it can be bad, but it's up in the atmosphere, which helps. But if something actually makes it to the surface, that is a whole different ball game. And so starting around a 100 meters across, around 300 feet across, that's when you start to get you start to see craters. Like a 100 meter asteroid hitting our planet will leave roughly a 1 kilometer crater behind. And if you want a sense of scale of how nasty this can get, once you're in the range of, yeah, a 130 meters across to a 140, a 150 meters, you know, somewhere in that range, we're talking between 45 100 feet across.

Once you're in that range, when the asteroid hits our atmosphere, it delivers an enormous amount of energy, but our atmosphere slows it down. There's a great fireball and it looks awesome. But and which saps some of its energy, but then a certain amount of energy actually makes it to the surface and explodes when it hits the ground. And the amount of energy actually reaching the ground here is roughly equivalent to the Tsar Bomba. This is the largest, most powerful nuclear weapon ever detonated.

We're talking in the range of 50 megatons. That's big. That leaves a crater diameter of around 2 kilometers, and it goes up from there. A kilometer scale, asteroid hitting our atmosphere, and it and it strikes the ground. It delivers something like 40 to 50000 megatons, which by my calculations is a lot.

That leaves a crater diameter of around 10 kilometers. Now the good news is that these are really rare. So, like, the small stuff, the stuff that's a few meters across, that happens, you know, every year or so. The nuclear weapon scale ones happen every decade or so. The bigger ones like the Chelyabinsk meteor, that only happens every, you know, once or twice a century.

And then it goes up from there. Then you're talking 1000 of years. For the biggest ones, like kilometer scale ones, we estimate roughly half a 1000000 years between impacts. And what I believe are the biggest existential risks to humanity aren't just the big ones, like the dinosaur killer ones, which are capable of destroying a good fraction of our biosphere. It's the smaller ones.

The smaller ones. Because, you know, if you drop a Tsar Bomba on a major metropolitan area, that's gonna be bad. If you drop it off the coast, that's gonna be bad because you'll get nasty tsunamis. There there's going to be a horrible catastrophe. Even one of these medium sized ones, you know, 100 meters across 200 meters across.

Those would create a disaster unparalleled in human history. And those big ones, not the dinosaur killer ones, but the just really really nasty ones happen, you know, 10 to 20000 years. Tens of 1000 of years or less. That to me, that that shifts the thinking here. Because the biggest ones that happen every half 1000000 years well, like, humanity hasn't even been around as a species for half a 1000000 years.

So it's like so far out of anything we could possibly prepare for or plan for or even grapple with. It's it's just so far beyond. But the medium ones, the space czar Bombas happen on the scale of every few 1000 years and those are human timescales. We have buildings. We have records.

We have cultural memories going back 1000 of years. This is within human timescales and human reckoning. And to me, personally, those are the ones that we need to worry about the most because those are the ones that can really, really create a disaster unlike anything we've ever seen, and it can happen within the timescale of human civilization. The fact that we haven't seen one yet in our 1000 of years of recorded written history means that it's gonna happen any day now to me. So what do we do about it?

It's hard to assess because we're talking about existential risks here. After all, these are risks that have a low chance of happening. Even something that only happens once every 10000 years, you are likely to live your entire life without having to worry about it. There's a low chance of happening, but there's a huge cost. You know, it's like a reverse lottery.

You're likely to not win, and you're going to be happy that you don't win. And if you happen to win the near Earth Object lottery, it's going to be the worst thing that has ever happened to you, to your city, to your country, to us as a human civilization and species. So what are our options? Option 1 is to do nothing. Seriously, it's not the greatest option, but it is an option.

Look, these are threats that we we can't really prevent, can we? You know, if the sun were to send a giant full solar flare in our direction, there's not much we can do about it. If a supernova were were to go off and boil away our atmosphere, there's not much we can do about it. These great cosmic threats, you know, were so puny compared to the scale of the cosmos that there's not much we can do. So why why spend money on it?

Right? We've got a lot of things that we need to spend money on. Should we this is a very valid question. Should we spend money on something that we don't know is going to actually harm us or not? And we don't know if we we can actually reasonably respond to the threat if we are able to detect it.

Sometimes it's worth it to just not spend the money. Downside, there's a small chance of everyone dying. You know? So you got you gotta you gotta weigh the pros and cons here. Option 2 is patreon.com/pmsutter.

If you contribute to this show, I will do my very best to prevent the next asteroid impact or calamity. And don't forget, I'm running a special promotion, on Patreon. If you subscribe at the $25 a month level and up by the end of March. By March 31st, if you sign up by then, then first thing in April, I will get your address and I will send you a free copy of my latest book, Rescuing Signs, Restoring Trust in an Age of Doubt. You don't have to keep the subscription.

It's cool. I just wanna get the books out there, and that's a way to do it. And I thank you so much for all of your support. The real option too. The real option too is is to spend it all.

You know? Just go all out. Figure out ways to monitor every kind of space rock, everything we can do about it, develop the technology, have the the rockets on standby, everything to maximize our production. The downside is, well, we we don't know if we actually have to spend that money, so it might be a waste. And we don't get to live the lives we wanna live because we won't have any money left to spend on anything else.

We're all just sitting there spending all our money on rockets and observatories and, you know, all the the threat detection scenarios. And we we gear our society to that, and we we don't get to do anything else for fun. So, you know, downside. And then it may not work after all. So option 3 is something in between, where we spend some resources, some time, some money, some people, but not all.

We decide on some level of protection balanced against the cost and the actual risk of the actual threat and hope for the best from there. This strategy is a combination of both finding the most dangerous threats and then coming up with ways of dealing with them. And it's this thinking, this middle ground strategy where we know we can't eliminate all risk, just like you can't eliminate all risk in your lives. We'll try our best to eliminate some of the risk, but balanced against the cost and balanced against how much we're willing to spend on it and what we can actually accomplish with our technology. It's this thinking that led the US Congress to issue a mandate in 2,005 that we develop the ability to identify, track, and characterize 90% of near Earth objects at least 140 meters across.

Why 140 meters? Well, there's an interesting intersection here. 1140 meters across is roughly czar Bomba level. So we figure as a society, like according to this mandate, if it's going to be anything less powerful than our most powerful nuclear bomb, we're willing to just suck it up. You know, it it'll be horrible and it'll be a disaster, but we already have a world filled with bombs that powerful, and we're already trying to figure out how to handle that.

So if we can handle that and, like, live with that reality that any day now, one of our cities may go up. This is getting really grim, folks. I'm sorry. Then if we're if we can accept the risk that we do it to ourselves, then we can accept that risk from space. But anything bigger than a Tsar Bomba, anything bigger than our most powerful nuclear weapon ever, Yeah.

That's something we're not quite willing to accept. So there's that intersection of our most powerful nuclear bombs and also with our our technological capabilities. A 140 meters across for a typical asteroid corresponds to an absolute magnitude of 22. And if you don't know what absolute magnitudes are, don't worry about it. It doesn't matter.

It's just a certain brightness threshold. If you want to go after smaller rocks and try to spot them, they are by definition smaller, they are less bright, and they are harder to see. So you need bigger telescopes, you need more dedicated time, you need more scientists, you need more sophisticated algorithms, you need a whole another level of infrastructure to to capture those smaller rocks, to see them. So with our given level of technology, with the kind of telescopes we have, with the kind of resources that we can devote to this cause, where we're not going to have dedicated observatories, you know, around the world and task every astronomer for doing asteroid defense. Like, this is something that we feel like we can actually pull off.

So that was in 2005. It is now 2024. The mandate was to be able to identify and track and characterize 90% of near Earth objects greater than this size, and so far we've got about 30%. Okay. Okay.

We've got some work cut out for this. Oh, wait. That's, 30% of identifying and tracking, and that's not characterizing, which was the last part of the mandate. Well, how many have we characterized? How many have we oh, less than, yeah, less than 5%.

Okay. Okay. Oh, is is anyone else feeling a little uncomfortable? Starting to look up at the sky, and I'm just wondering if there's something we're missing. But let's okay.

We're working on. We're working on. Let's get a positive spin on this episode. So it's important to do all 3 to identify, track, and to character eyes. Identifying is simple.

That's just spotting a dim and fast moving object. It's simple. It's not easy because asteroids are small. They're very, very quick. They zoom around the sky.

And so you have to spot this, like, little speck of light, and then you look in the same piece of sky the next night. And if that tiny, tiny little speck of light, which is so dim, it just might be a little bit of noise. If it moves, you might have an asteroid. So that's identifying. Boom.

We've found an an asteroid. We've found an object. The next step is to track, and that's because asteroid orbits are highly unpredictable. They are so small. They are so easily influenced by the position of the planets, by interactions with each other, even the gas giant planets.

Like, if Jupiter is over here and then moves over there, that's going to change the orbit of an asteroid in a very unpredictable way. They are very hard to keep track of. They are very hard to predict where they're going to move through the solar system because so many things affect their orbits. Like, even their color will affect their orbit because if they're, like, dark on one side and light on the other, then they receive different amounts of sunlight in that tiny, tiny little bit of radiation pressure difference from one side to the other where one side light is getting absorbed and the other side light is getting reflected just a tiny bit more. That tiny difference in radiation pressure acts like a little really, really awful solar sail, and it can actually change the momentum of the asteroid.

You have to keep track of that. If it moves through, like a a region with slightly higher density, say there's like comet trail in the in there's like one little impact, that one little impact can can change its orbit. It's like tracking these are are it's tough, requires continuous observation. And then you need to characterize it. You you need to know what kind of asteroid we're dealing with.

You need to know its shape, if it's tumbling. If so, how is it tumbling? That will affect its orbit too. Its motion through space too. Because of all these interactions, gravity will act on a spherical asteroid differently than a peanut shaped one or really lumpy one.

That will cause a change. You have to pay attention to this. And then if it hits us, you really want to know what it's made of. If it's really loose, if it's really dense, is there are there heavy metals? Is it mostly water?

This all this all affects the impact scenario. You need to do all 3, identify, track, and characterize so that you can have the best threat response and the best ability to deal with it. And we haven't done that great of a job at tracking asteroids and near Earth objects because usually asteroid hunting is done as a side hustle for other observatories. You know, astronomers build telescopes to do all sorts of cool things. And, you know, to be fair, pointing a telescope at the sky is exactly what we need for asteroid hunting.

But, usually, observatories are built with other things in mind to do other things, to have other targets. And then if there's any spare time, we use it for asteroid hunting. And because these telescopes are not optimized for asteroid hunting, they tend to miss a lot. For example, there's the dark energy survey. That's a 4 meter telescope in in Chile, and its mission is to map stuff in the distant universe to try to understand dark energy.

It's also used as an asteroid hunting telescope because it's pointing at the sky a lot, but it's not the greatest at it. That's why we haven't caught a lot so far even though it's been nearly 2 decades since the mandate. In 2025, this will change with the Veracy Rubin Observatory when it achieves first light. It has an 8.4 meter primary mirror. And this telescope is designed to image the entire available sky every few nights.

And so it will be a premier asteroid hunting telescope. It has a wide variety of missions. It's a general purpose telescope just designed to look at the whole sky every few every few nights. It'll be amazing. And because of that constant remapping, it will be able to pick out the motions of asteroids with relative ease.

I say relative because, you know, you have to sift through absolute mountains of data with sophisticated purpose built algorithms. And so it's not exactly easy, but it's relatively easy, especially with the giant telescope that's staring at the sky all the time. And we need to take a quick pause so that I can let you know that this show is sponsored by BetterHelp. You know, we've talked a lot about time in this series. What is the nature of time?

There's all sorts of physics concepts that we explore about the nature of time, but there's also this human part of time or the experience of time that we all know so intimately and yet we don't understand. And one of the biggest things about time is that we all wish we had more of it. Like, if there's an extra hour in the day or if we could just put things on pause, what would we do? I'd probably do more episodes. I don't know.

But, like, we all wish that time was different. And one of the coolest things about therapy that I've seen in my own experience is that, you know, by realigning your perspectives, by realigning your expectations, you can get a better sense of your own flow of time. So that time does its thing outside of our control, but you can be a part of that flow. If you're thinking of starting therapy, give BetterHelp a try. It's entirely online.

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That's part 1. Let's say in the next few years, we will be able to identify and track and characterize a potentially threatening asteroid. And then what? If we're gonna follow through with our plan, then we need a part 2. We need to do something about it.

We said, okay. There it is. We found the asteroid. We tracked it. It's on a collision course with Earth.

Here's the probabilities. What are we gonna do? Well, one choice is to move it. That's, that's tough to say the least. The smallest asteroids we can comprehensively identify, you know, following this congressional mandate, the 140 meter wide ones, these are the Tsar Bomba level asteroids.

These things weigh roughly 100,000,000,000 kilograms. Now that's a large number, but we move that kind of stuff on the earth all the time. For example, the Great Pyramids of Giza weigh in around a few 1000000000 kilograms, and those were built by by hand, basically. So we as humanity are capable of moving billions of kilograms worth of stuff, but, you know, that takes a lot of tools, and workers, and time, And in space, you know, we need a lot of shovels. If you wanna move a few 1,000,000,000 kilograms of material, we can do it.

It just takes a lot of sweat. In space, well, we don't have a lot to work with. We don't have massive machines. We don't want backhoes, shovels, picks, lots of really bored people, you know, just putting in the sweat. We don't have any of that in space.

So we have to figure out how to move a literal mountain without any of our usual mountain moving tools available to us. That is the challenge. If we see a threat headed towards the earth, we need it to point not at the earth. Anywhere but the earth. You can go anywhere you want an asteroid.

You you don't have to go home, but you can't stay here. That's our goal. And we have to move 1,000,000,000 of kilograms of stuff. 100 of 1,000,000,000 of kilograms of stuff. So, okay.

How can we move it? We can slam into it, which sounds silly, but we were actually able to perform this. We actually able to do this with NASA's DART mission, the double asteroid redirect test mission, which as missions go was pretty straightforward that we launched a satellite spacecraft into space. It was very simple. Had like a camera, some propulsion thrusters for fine tuned maneuvering and some comms gear to radio back home.

And then we just slammed it into the face of an asteroid and it worked. We were able to move it, which is pretty cool. We were able to measurably change an orbit of a small little moonlet of another asteroid. What that showed was that, yes, in principle, we can slam things into asteroids and change where they move, which is great. But if you're not so much into the whole slamming thing, then there's another approach called a gravity tractor, which is way less sci fi than it sounds.

I'm sorry. It has a cool name, but it's actually you know, there's no there's no sci fi wizardry here. What you do is you put a spacecraft in orbit around an asteroid, and then you slowly change the orientation of your spacecraft Very, very slowly like it's orbiting one way and then you just change that orbit a little bit. And then very, very slowly, the gravitational pull from the satellite onto the asteroid pulls that asteroid in a slightly different direction. It is achingly slow, but it does work at least in principle.

Another way to move a giant asteroid is to coat it in reflective paint. You know, just spray it on. Just tag it, And that will cause part of the asteroid to reflect sunlight in a different way, which will change its orbit. Or you don't have to slam into it. You can have a nearby explosion.

Say you send a nuke next to the asteroid and then blow it up. Blow up the nuke that is, and then let the material from the explosion, the radiation and the material strike one side of the asteroid. So you just kinda just just, like, breathe on it and let it go in a different direction. So the point of all of these is to nudge an asteroid just a tiny bit. This only works if we see the asteroid soon enough.

That's the only way we can pull it off. Because all of these options slamming into it, gravity tractor, reflective paint, adjacent explosion. These aren't going to move 100 of billions of kilograms very, very much. If you set off a bomb next to Mount Everest, Mount Everest is gonna move a tiny bit, but not by much. But that's okay.

If you see an asteroid soon enough and it's far enough out in its orbit, and if you give it a tiny little nudge, then that tiny little nudge, that tiny little difference will add up over the 1,000,000 of kilometers that that asteroid will travel. So by the time it gets to the Earth orbit, it's it's totally far away from us. This only works if we have the capability to monitor, to track, to identify, to characterize, and have a response plan ready in case we see that threat. Basically, we're talking years in advance for a general ballpark. We need to be years in advance of a potential impact if we want any hope of dealing with it.

And there's a risk here too. And there's a risk here because asteroid orbits are extremely complex and nuanced and have a lot of uncertainty. So we need to be when we send a mission, say we send a dart style mission to slam into an asteroid that's potentially going to hit the Earth. We need to be absolutely sure of 2 things. 1, that its original course was going to hit the Earth.

And 2, that after the impact, it's definitely not going to hit the Earth. Because if we're wrong on either of those, we're we're done. Because if the asteroid was not actually going to hit the Earth, then when we hit it, we might just knock it into a path that will make it hit the Earth. And if we get our knocking wrong, if we get our gravity tractor wrong, if we paint it weird, or if we, you know, detonate at the wrong time or or hit off axis, it just won't work. We may nudge the asteroid, but then, okay, instead of hitting New York, we hit Tokyo.

That didn't really help much. And asteroid orbits are exceedingly complex and difficult, so we need to see the asteroid well in advance. We need to be able to track it well enough that we can pinpoint its trajectory and know for sure that it's going to hit the Earth. And then we need enough sophistication and confidence in our solution that we know that once we do the thing, slam into it, blow up something next to it, paint it, whatever, that it's definitely not going to hit the Earth. There's another approach that I'm kind of a fan of, which is a little bit more forgiving, let's say, in its approach.

And this choice is to blow it up. Yes. That is the plot of the classic Bruce Willis movie, Armageddon. And believe it or not, that movie is based on real science. So here's the thing.

We used to think, for a while that, okay, our best bet would be to blow up an asteroid, but asteroids are our best character characterized as what are called rubble piles. They're not like solid rocks. It's not like granite mountain here. It's actually a bunch of boulders and all these boulders are relatively small, and then there's a bunch of sand and grit between it between them. And then they're all just kind of very loosely held together with their own gravity.

They're not really tightly connected to each other. And at first, this was seen as a detriment for trying to blow up an asteroid because if you, say, were to bury a nuclear bomb inside of an asteroid and detonate it, you you don't really blow up the asteroid. You don't vaporize it. Most of the energy is just absorbed by the loose rubble pile. You know, it shakes things up a bit.

It gets a little puffier, but then it doesn't actually disintegrate the way you want, which is why we started investigating while slamming into it instead or blowing up something next to it or painting it a different color, you know, all these other solutions to try to alter their orbits. But you can use this rubble pile idea to your advantage. And that is to do exactly what I said, put a nuke in the center of it and blow it up. No. It's not going to eradicate the asteroid.

It won't destroy it, but that's not the point. The point is to fragment it. Because the danger of an asteroid is when you have a giant object slamming into our atmosphere, and it's too big for our atmosphere to absorb. It can't bleed off that energy and heat and light. It can't it can't take away that energy and then it hits our crust and it leaves a crater and there's a big Tsar Bomba.

But if you fragment it, even if you just have a loose collection of boulders, but as long as those boulders are spread out a little bit in space, then each individual boulder strikes our atmosphere and each individual boulder our atmosphere can handle. You know, boulder comes in. Okay. We evaporate that. And now here's another and one right next to and one on top of.

But our atmosphere can absorb all that energy because it's being broken up into lots of smaller bits. This idea is totally untested and also likely to never be tested because it involves nuclear bombs, and launching nuclear bombs into space is something we've generally frowned upon as a society. But still, I think it's a cool idea. It's worth investigating because, there's there's more room for error here. There's more forgiveness here because we're not trying to calculate the complex orbital dynamics and make sure we're exactly right and then make sure we hit it in exactly the right way to get it off course.

This is we just assume it's going to hit the Earth. And then our our sole goal is to deliver a lot of energy to that asteroid so that it can fragment. And so and then you're done. And then you're done. And it doesn't matter if the asteroid is far away or close, as long as you can get to it and fragment it in time, and fragmenting does not take a lot of time, as long as you can disperse the asteroid.

It could be years away. It could be next month. As long as you can disperse the asteroid, then our atmosphere can absorb its individual pieces. Now would it be worth it to investigate this, to spend more money and time and resources? Well, that's up to us.

Right? Like, balancing all this, all of life is a balancing act of wanting to live your life, but also trying to manage your risks. And it's for sure hard to navigate these kinds of existential risks that are rare, only happen every few 1000 years or every few tens of 1000 of years, but would be the worst disaster to befall humanity. I have no answer to that question on what is the best level of preparedness, and how much resources, how much money, how much time do we spend in this direction versus wanting to just enjoy the night sky for what it is, and our lives are what it is. It's up to us to decide.

I vote for blowing up asteroids, by the way, because instead of the end of civilization, we would just get the best fireworks show that humanity has ever seen, and that's cool to me. Thank you to Jennifer h and Gary w for the questions that led to today's episode. Thank you to my top Patreon contributors. That's patreon.com/pmsutter. Don't forget if you subscribe by the end of March at $25 a month and up, then I will send you a free book, which I think is pretty cool.

And then you can cancel right after that. I'm fine with that. It's totally cool. Thank you to my top contributors this month. Justin g, Chris l, Barbara k, Alberto m, Duncan m, Corey d, Nyla, John s, Joshua Scott m, Rob h, Lewis m, John w, Alexis Gilbert m, Valor h, Demetrius j, Nathan r, and Mike g.

That's patreon.com/pmsutter. Thank you so much for all of your support, and thank you. Thank you everyone for sending in all these amazing questions. I get questions almost every single day. I've got an amazing backlog, but I love getting more.

Send those questions to askaspaceman@gmail.com, or look up askaspaceman.com for the show archive, and there's a way you can contact me through the website there. And otherwise, I will see you next time for more complete knowledge of time and space.

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