Mark Boslough on the Dangers of Climate Change and Destructive Asteroids

March 21, 2019

Mark Boslough

Mark Boslough is a Caltech-trained physicist and CSI Fellow who spent 34 years at Sandia National Laboratories doing research on hypervelocity impacts, energetic materials, explosions, and global risk from asteroid impacts and climate change. He has participated in many science documentaries with field expeditions to airburst locations including the Libyan Desert of Egypt in 2006, Tunguska in 2008, Chelyabinsk in 2013, and the Nevada Test Site in 2017.

Chelyabinsk meteor
Chelyabinsk meteor

Jim Underdown sits down with Mark Boslough to talk about Boslough’s career as a scientist and his work refuting the bogus claims of climate change deniers. They also dive into everything you’ve ever wanted to know about asteroids, meteoroids, and comets and what would happen if the Earth was struck by one.

New music heard on this episode

“Wahre” by Blue Dot Sessions / CC BY-NC 4.0

“SuzyB” by Blue Dot Sessions / CC BY-NC 4.0

Links Mentioned in this Episode

Hello, everybody, I’m your host Jim Underdown welcoming you to another episode of Point of Inquiry. So do you think your day is going badly today? I’m point of inquiry. 

We’ll be talking about a couple of subjects that could really ruin your day. One, climate change is already probably ruining some of your days each year because humans are warming the atmosphere, the extremes we’d normally see every year in the form of drought, floods, hurricanes, tornadoes and blizzards, to name a few, are more likely to be worse because there is more energy in the atmosphere. That’s right. Climate deniers, even snowstorms, can be harsher due to global warming. Later on, we’ll cover the other topic that might change the face of your day, especially if one happens to land in your neighborhood. I’m talking about asteroid impacts. I spoke to someone who knows an awful lot about both of these subjects. Mark Borislow Mark holds a Bachelor of Science in physics at Colorado State University and an M.S. in APHC and applied physics from the California Institute of Technology. He’s on a team that works on what to do if an asteroid has us in its crosshairs. And he’s also on our team as a fellow of CSI, our own Committee for Skeptical Inquiry. Ladies and gentlemen, Mark Basilone. 

It’s just a few days after Psychon 2018. And I saw your talk. Actually, I introduced you. That’s right. You did. You did a workshop on the first day. 

And it was fascinating. Although a little disturbing, your talk was on climate change. What is the strongest statement you can make about climate change or the general public? Because there seems to be all this controversy about it, like it’s in question and being presented as being this big debate from your side. What is the position? 

Well, I think it’s incontrovertible. Climate change and global warming is the inevitable consequence of the laws of physics. When you put heat trapping gases into the atmosphere, the concentrations that we have been, I mean, it’s there’s really no argument within the scientific community. It’s fully accepted. And the American physical society said that it was incontrovertible. That word actually was taken out of the statement. But in my opinion, for political reasons, they wanted to soften it. 

Who do you think took the word incontrovertible out? 

There was a whole study by the American Physical Society. People just didn’t like sounding that certain. Even though I think in the opinions of the people who do the research, that word is appropriate in your mind and in the world of the, well, all climate scientists. 

This is a man caused a human caused. 

Absolutely. Issue. Yeah. The Intergovernmental Panel on Climate Change every five years or so issue a report. And every time they issue a report, the statement is stronger going, you know, from the early days where they used very soft, reticent language to now. There was a recent report that just came out in the last few months. It wasn’t one of the five year reports. It was a special report basically on what what do we have to do to hold global warming below the one and a half degrees C, two point seven degrees Fahrenheit above which we really could have catastrophic changes. And we don’t have a very long timeline for that. 

So they’re not even talking about if this is happening anymore. It’s we need to start moving. 

Yeah. And the language was well, started off. 

You know, we can see the human fingerprint on climate change, too. You know, it’s a significant factor, too. It’s the dominant factor, too. It’s basically everything we’re seeing is the entire amount of global warming is attributable to human causes. 

And and so how do we know that? Are we looking at a specific timeline that points to human activity or what? 

Well, really, it’s post-industrial industrial revolution, yet post-industrial revolution. When we really started burning fossil fuels and in temperature measurements, direct temperature measurements globally didn’t start till the late 19th century. So we don’t have that long a record. And there is a lot of natural variation superimposed on that, as well as other variation, such as smog. The existence of smog also has a cooling effect. And so, ironically, with the Clean Air Act cleaning up and burning less, you know, fuels that don’t create as much aerosol or particulate pollution, that decreases the reflectivity of the earth. I should say kind of say it the other way around. The smog increases the reflectivity of the earth, that it reflects more incoming solar radiation, which keep prevents the world from heating up as fast as it would otherwise. And there still is a large part of the world. There still is a lot of smog that’s keeping the earth cooler than it would be otherwise because the particles in the air keep the sun’s rays from hitting the surface. 

That’s right. 

And as that pollution waxes and wanes, that also causes fluctuations in the Earth’s global climate, as well as the natural variation, which really has more to do with uptake of heat by the oceans than anything else. 

But it seems to me I’ve already I’ve also seen like a large volcanic eruption or multiple eruptions. Can have a small effect. 

Right. And then 90s, we had Mount Pinatubo and the Philippines erupted. And that caused the fluctuation that lasted about a year or so. And so there was a there was a decrease in global temperature or at least a decrease in the in the rate of increase of global temperature. 

So it didn’t turn it around. It just slowed out of it. 

Well, there are pauses. And so I know well, 98 was a was a big El Nino year and 1998. And for a long time, that was the record setting year. But that’s been overtaken. 

Now, what is your training? I mean, not what how do you become where does your knowledge come from about all this? 

Well, I’m trained as a physicist. I got my undergraduate degree in physics. And then I went to Caltech and got a degree in applied physics. But I did my research and geophysics. 

And when I was doing my JUIF physics degree, I took a lot of courses in planetary science, which included some planetary atmospheric science. I got very interested in Earth’s climate in association with impacts. The effect of asteroid impacts on the Earth and mass extinctions. 

And it turns out, for example, that the dinosaur killer asteroid 66 million years ago, it wasn’t the asteroid. It didn’t kill them directly. It really the long term extinction had to do with climate change more than it did with the impact itself. So the impact triggered it directly or indirectly triggered a climate change. 

And that collapsed ecosystems in the food chain and that caused the dinosaurs to die. At least that’s what we think. 

I’m just amazed at the the level of disconnect people have. We keep hearing climate change and global warming. Now, it seems to be more and more even when people falsely attribute it. Like every time a big, strong hurricane hits. 

People talk about it or any weird weather. They talk about it, which is not really. Right. Right. I mean, freak things have always happened. Right. And weather. 

But but the because the atmosphere has more energy in it. It’s warmer. It holds more moisture. So in the ocean, sea is is warmer. So evaporation is happening as well. So basically the the climate is juiced up from all this extra energy. And there’s a lot more water vapor in the atmosphere than there used to be. And so when there are storms, they tend to be bigger. The biggest storms tend to be bigger. That’s one of the predictions. And large precipitation events are bigger and we are observing that. 

And that’s why you see the like the sets of worst storms have tended to all happened more recently in the sense of the warmest years of all happened recently. And that’s the connection. 

That’s right. So so we have been seeing a trend towards the worst storms being worse. So the biggest and strongest storms and the biggest flood events tending to be bigger. So the trend is going up. We do have the problem of a limited record. We didn’t have satellites, for example, on that’s fairly recent. But we do see, you know, the window that we’re looking at shows a worsening trend. 

And so, I mean, how do you infer temperatures and other climate data from the past? 

What sort of techniques do you used to read the geology or the ice or whatever to figure out what was going on before records were being taken? 

Well, there is a whole field of paleoclimatology and and people look at what they call proxies to determine temperatures. 

And those include tree rings, isotope studies looking at Spillett, Ms. Stalactites and still at mites, corals. And ocean sediments and little critters that die and fall to the bottom of the ocean looking at the isotope signatures and those that have a signature of temperature in them. So combining all those together, you can create a proxy for temperature. And that shows a very sharp upward trend. 

And all those just to confirm all those things are in agreement with each other. There’s the. Those stalactites agree with the critters that fall the bottom of the ocean and the tree rings, there’s no missing right. 

And what you can do from those is track the temperature of the earth’s past before thermometers were invented. And you don’t see any deviations like we are seeing now. One of the earliest global or at least hemispheric reconstruction reconstruction for the northern hemisphere was in the 9th, 1998 paper by man Bradley and Hughes. And that graph became known as the hockey stick because you see very blat, in fact, gradually decreasing temperature trend over the last thousand years or so. And then in that 20th century, a very sharp uptick, which was like the blade of a hockey stick. 

What’s the controversy surrounding that? 

There was there were a lot of critics that said, well, he didn’t do the statistics right or tree rings don’t work well by themselves. There is an issue with with tree rings that in the 20th century they don’t continue to track because they’re sensitive to other things, other climate related effects besides just temperature. But altogether, you know, air, everything combined does show a rapid increase. And of course, now we have thermometers. So we do know that the temperature of global temperature is continuing to go up very sharply. But since that work was done, there’s been a number of independent studies that have confirmed it. Nobody who has done paleoclimate reconstruction, combined with modern temperature thermometer measurements, sees anything other than a hockey stick. 

So we were we are supposed to be the trend prior to the industrial revolution was getting cooler or we were supposed to be heading to an ice age or. 

Well, yeah, we’re in an interglacial. So we have these. We have these glacial interglacial cycles that are really driven by the Earth’s orbit around the sun. So, you know, the Earth’s axis is tilted, but that the degree of tilt changes very gradually with time. The obliquity. So there is an obliquity driven aspect of that that change as the earth tips over a little bit more and a little bit less. That changes the distribution of the Sun’s incoming solar radiation on the earth. So there’s a distribution with latitude. There’s also the shape of the orbit changes. So the eccentricity of the orbit changes. It becomes more elongated and more circular with time. And then there’s also kind of a rotation of the Earth’s axis. The tilt of the Earth’s axis points in different ways. That’s a procession. And these things happen. The parameters change over over timescales of tens of thousands of years. And combined that that can cause more ice to build up at high northern latitudes. And you can get big ice sheets. And then as it changes around it, it melts and you get these interglacial periods. So we’re in an interglacial now. The last glacial maximum was something like 20000 thousand years ago. Most of it melted off. What’s left to high northern latitudes now is a very small fraction of what we had. You know, when. When. What’s now? Chicago was under kilometer or more. 

Yeah, we used to learn about the Marines and things in Wisconsin and this was all formed by massive ice sheets. 

So now the northern hemisphere should gradually be cooling and that is observed in the hockey stick stick graph. So if you took away all this artificial heat trapping gas and we had the natural amount of CO2 in the atmosphere, the earth would be on a very, very slow, gradual cooling trend going for toward the next ice age. 

It was a surprise to learn that the heating of the oceans, the current ocean rise and the catastrophic ocean rise, it could be is is in our future. If we don’t do anything, I always just envision glaciers melting and filling up the oceans. 

But really, it expands as why there’s a there’s a strong thermal expansion component to that. So much of the sea level rise that we’re experienced is just due to the. 

Thermal expansion of the water. If anything, the oceans are heating, that’s fat, that takes much less time than. 

Or Urd has a bigger effect, right? 

Well, it’s it’s been the dominant effect. But, you know, if we lose an ice sheet off of Greenland or Western or the Western Antarctic ice sheet, that could lead to a very on a geologic timescale that could lead to a very abrupt increase in sea level. 

And we’ve seen that. We’ve seen large Delaware sized ice sheets. 

Yeah, there is a there’s definitely a contribution to that. Now, that Delaware sized ice sheet, that was sea ice. So when that breaks off. That doesn’t raise sea level because it’s already floating. But they’re especially in Antarctica. There is an effect. But also Greenland. There’s an effect of this sea ice that buttresses the ice sheet that’s sitting on the land. So we have to worry a little bit because we don’t fully understand the physics. We haven’t, you know you know, we haven’t gotten a reproducible model because we really only have one earth. And so we can model what might happen in the future. But then we have to wait for the future to see if it if it really happens. But as this sea ice continues to break up, there won’t be the buster icing that holds up the land ice and the rate at which land ice falls off these Greenland and the continent of Antarctica. That could increase. And now you’re taking ice that’s sitting on land and putting in the water. 

And the displacement of that will cause sea level to rise. 

This is where it gets political and this is what gets everybody upset. 

What to do about this? You have any thoughts about why so sort of large measures that can put the brakes on all of this? 

Well, I’m a physicist, not a politician or an economist. 

I’m a strong believer in capitalism and just the. Fundamental laws. I mean, they’re not. 

It’s not a lot of physics, but it’s almost as strong and that’s supply and demand and how markets work. And so I do think that we need a market based system which would require a price on carbon. Normally so. So the US government raises revenue and and U.S. government and states have often put taxes on things that it’s called a sin tax. Right. Who is tobacco? Who’s tobacco? Things that actually cause damage to human health or increasing risk or or gambling? You know, that can hurt people’s personal finances. And so it makes sense since we know that greenhouse gases cause damage, heat trapping gases are causing damage. And, you know, people say, well, you know, why is a warmer earth damaging? Well, it’s it’s really because the earth is you know, humans are infrastructure. Everything we do is optimized for the stable climate that was there when it was built, when our infrastructure was built, when we evolved everything, ecosystems, everything’s optimized. And it will have to re optimize itself. But that re optimization will be very costly. Right. 

Like relocating a building a wall around Miami, Florida, for starters. 

Right. So there’s there’s nothing fundamentally optimal about the Earth’s current state or current temperature. You know, people ask, well, why is the current temperature better than two or three degrees warmer? And it’s like what is optimal about the current sea level? Nothing fundamental, except that most of our cities are old. Many of our cities are on the coast. The Navy builds its ports with that sea level and taken into account. And if sea level changes in those ports and those cities are underwater, they’re no longer usable. That’s worse. 

It’ll get just a little expensive, more expensive than the right syntax. So, so. 

So that’s my argument for more heat trapping gases being a bad thing, just like more tobacco and more gambling and more alcohol. And a lot of these things are bad for human health. That’s not an argument. 

So you tax gasoline and absolute other. Yeah. So any other examples? 


I mean, basically anything that produces pollution, CO2 or methane pollution, you tax it and you tax it in a way that’s maybe proportional to, you know, the concentration of of the you know, of the greenhouse gases. There’s more in coal, for example, than there is in naphthalene per Beatty. Beatty, you produced. So you can tax it that way. And also in proportion to how much damage, how much the damage costs. And as we as the temperature continues to go up, it’s going to continue to get worse and worse. And so somehow you need an increasing tax rate or increasing rate per ton. It would be nice to be able to kick that in automatically. So, for example, you can index it according to the global mean surface temperature anomaly as as determined by NASA, for example. And it would be really nice, actually, if we could replace our income tax with a carbon tax. So it’s revenue neutral, doesn’t cost people any more than their income taxes now. And you know what? Earning income is a good thing. That’s probably not the thing that should be taxed. It’s what you do with your income. Maybe that should be taxed according to how much damage that thing does now. 

But our president is trying to bring coal back into prominence. Some people say that there’s scrubbers on coal energy and that it’s it’s cleaner than people think of it. Well, how do you risk. 

No, I mean, I think clean coal is a myth and the term clean coal gets used differently by different people. I mean, you know, if you think of greenhouse gases as being the dirty thing that comes out of coal, then coal is very dirty. If your eyes saw in the thermal infrared, if you were sensitive to the thermal infrared, the sky would be a different color now due to the burning of coal. So you can think of all coal as being dirty. It’s always a puzzle to me. You know, the Republican Party used to be the party of free market capitalism. You know, if something can’t make its way, it should die. 

And so why now? Do they want to subsidize coal? Subsidize something that can’t make it on? Tone. I mean, coal is a dying industry. It’s not just harmful. It’s not doesn’t make economic sense. 

Let’s shift gears here from Floridians being neck deep in ocean water to all of us dying, a fiery asteroid induced death while drinking scotch and smoking a cigar. 

Is there any other way to go? First, some quick background. 

Basically, an asteroid is a chunk of something floating around in space that is a meter or greater in diameter. There are millions of them out there. One one makes it into our atmosphere. It can do anything from hit the middle of the ocean unnoticed to breaking a gazillion windows like the meteorite that broke up over Chelyabinsk, Russia, in 2013 and injured over a thousand people all the way up to the Chick Shlub asteroid, which was a bad day for the dinosaurs 66 million years ago and a good day for our mammal ancestors. 

Another fun subject. Asteroid impacts defense. Pretty cool movies made about this stuff. Have you seen the news? 

Well, like deep impact. Yeah. And Armageddon. Yeah. 

Yeah. So those came out in the 90s? Nah, I think they were in large part inspired by the impact of comics. Shoemaker Levie nine on Jupiter. My community was talking about the threat of impacts. So when I was at Caltech in the late 70s, early 80s, I did impact experiments and I modeled the impact of asteroids and crater forming impacts. 

And were they all theoretical experiments or did you. Were you able to fool around with, like, shooting objects into the dirt? 

Well, we did. Actually, I did exactly that. And we had a what we call a two stage, like Gascón, which is an old Navy cannon. And it was modified so that the cannon was pump tube. It was filled with hydrogen gas. 

And then we’d burn powder in the breech shot plastic cylinder that pumped that hydrogen to very high pressure. And then it popped this metal diaphragm. And then there was a smaller projectile in this launch tube. And hydrogen can accelerate something to much higher speeds than burning powder down. That’s why you get these super high speeds five, six kilometers per second, which is a significant fraction of escape velocity or, you know, matching almost orbital varsity. 

And then we could look at the effects of that. And a lot of what we did was not just the production of impact craters, but actually studying materials at super high pressure to try to infer what the state of the Earth’s interior and planetaria interiors is. 

Oh, well, they shot a copper bullet at was it an asteroid or a plane? 

Yeah, that that was also called the Deep Impact. Same name as the movie. They threw a copper ball at at a comet and observed the formation of the crater. So it actually created a crater on this comet. 

And there are images of the ejecta. You can see the blast and the object of being sprayed out from that. 

And that tells you what how dense it is and what they were. 

They did have spectroscopy and all sorts of other instruments. So. So it was really the intent was more to sample the car. It was a way of sampling the comet and the material of the comet a little bit less focus on formation of the crater itself. 

And so were they also doing this with. 

Watching how much it would change the course of know, it was that particular experiment. The comet is actually too big to be affected by this little or be affected in a measurable way by this very small impact. 

Just the mass ratio between a copper projectile and comment was too big for for anything significant to be to be observed. 

Tom said enough. How big was the bullet for lack of a better term? I don’t recall. 

It was something like the size of a bathtub. If I remember right, it was it was pretty big. 

Yeah. I mean, people don’t realize that, especially when you’re going. High speed and slide multiple kilometers a second. Yeah. It doesn’t take much. The meteor I was at the meteor crater in Arizona. 

And as in the things, the better part of a mile across. Right. Yeah. And something the size of a school bus or something caused. 

Yeah. It was in there some. We don’t know exactly how fast it was going. The size of the crater is really determined by the kinetic energy. 

And so if there’s some uncertainty in velocity, that means there’s a big uncertainty in the mass. And the diameter. 

But it was, you know, maybe 40 meters in diameter, something like that, 30, 40 meters in diameter, depending on how fossick. Wow. 

Yeah, it was higher. And we do know that one was iron. How do you know that there are iron meteorites, ferrymen in the area. 

Canyon Diablo irons. And then there’s iron debris, oxidized iron near the crater. At the moment. Yeah. 

Yeah. It’s a big hole. And if something only maybe 30 or 40 meters across can make a mile. 

It is amazing. Yeah. 

And and so paint a little bit of a picture. Something like that heads. 

Most of the immediate area, I mean, there’s obviously a massive shockwave, right, fire. What else? Yeah. 

I mean, it’s like a nuclear explosion without the ionizing radiation. I mean, there’s very. 

A lot of thermal radiation, so there’s a lot of thermal damage. Fires from that just just temperatures as hot as the sun associated with the vaporizing cloud of asteroid. 

And then that the blast wave, the shockwave in the air. It’s it’s like a sonic boom, but it’s reinforced by the explosions. 

So the the object actually explodes. And when it when it vaporizes, it explodes. And there’s this expanding vapor cloud. And it’s also pushing this supersonic ball shock. This is equivalent to a sonic boom, only much more powerful. And that does incredible damage that was also observed at Tunguska. Nineteen oh eight explosion in Siberia, knocked all the trees down, knocked trees down over many square miles, something like two thousand, two thousand square kilometers. That was the area that spans the forest that was knocked down. 

So that’s the atmospheric shockwave. Before it even hits, that’s knocking all that. Or after. Maybe after. 

And interestingly, the 10 Gasca explosion and the meteor crater of the roof were roughly the same size and magnitude, we think, you know, somewhere between five and 10 megatons. So a large nuclear explosion, thermo thermonuclear bomb. Most of the energy at Meteor Crater was the source of of the explosion was at the surface because it was a very dense iron object that hit the ground, stayed together, made it. Yeah, mostly it was vaporizing as it came down. So. So there was a mixture of iron, vapor and solid iron that hit the ground. And it was the solid iron when the solid iron hit the ground, then it vaporized. So so there was a very local source of explosive energy at ground level, but it was also kind of exploding all the way down. So it was kind of like a moving nuclear explosion with a big boost at the very end when it hit the ground. Go. SCCA didn’t hit the ground. There’s no evidence that anything hit the ground. So it it was not iron. There’s no evidence that it was iron. We think it was probably a carbonaceous condor. Right. A lower density, weaker material. And it exploded probably at the top of the troposphere at the bottom of the stratosphere in that area. And it also exploded as it was coming down. So it was kind of like a continuous moving nuclear explosion, but it completely got used up while it was still at fairly high altitude. 

And then there was this expanding ball of vaporized of asteroid vapor that continued to push down and create created that blast wave that moved across the forest, knocking down trees. 

Can you make any generalizations what asteroids are made out of? Are there multiple different? 

Well, there are stone. You know, there are there are comments. Those aren’t asteroids. But there is really kind of a fuzzy line. We recognize now that the the line between comet and asteroid is a little bit fuzzy. Comets have volatile, more volatile material associated with them. Water, ice and methane ice. And and so when those explode, they’re, you know, low, lower density and smaller molecules that would makes the tails of comment and that stuff coming. Yeah. When those when they come close to the sun, if they haven’t been near the sun before, these volatiles will burn off and you get the the tails. There are dead comets that are more like asteroids where most of the volatiles have been burned off. But when those hit the earth, their lower density, they’re weaker. They tend to explode higher in the atmosphere and they carry less energy for a given diameter. They carry less energy given the diameter and the velocity, because the density is lower. So they’re lower mass. And then as you go up the scale, you have carbonaceous Kondor rights, which are mostly silicate. And then you have stony asteroids, stony iron asteroids and increasing density all the way up to the iron asteroids like the one that made meteor crater. 

And those are more likely to make it all the way to the surface for. 

For everything else held the same. Those are more likely to make it to the surface. But they’re not as common something only like 10 percent or so of asteroids or metal. Lucky for us. Yeah. Although you can argue I mean, you know, some of my models show that for asteroids of a certain size, like Meteor Crater. Comparing Meteor Crater to Tom Becka, everything else is saying if they had exactly the same energy. You’d be at more risk if you were near term Gasca than Meteor Crater because because when it’s explodes higher in the atmosphere, it does damage over a larger area. 

Space wise, you’re more likely to be in the air in the red zone. Exactly. Bad roads. Bad. Right. 

We know about lots of asteroids out there. How we’re keeping track. What’s going on with the tracking? 

Yeah. There’s a very active survey. And there’s big telescopes that are observing. And there have been this started in the early 90s and it accelerated. So we we found more than 90 percent, almost ninety five percent of the near Earth objects that are one kilometer in diameter or more. There’s roughly a thousand of those. And those are in orbits that either cross Earth’s orbit or come very close to Earth’s orbit. That potentially could be a risk. And none of those are on collision courses. So but that those are just the big ones. Those are the ones that could wipe out the planet. 

How small can we see out there and keep track? 

You know, there are discoveries of very small 10 on the order of 10 meters and diameter. You know, the size of Chelyabinsk, which was 20 meters. Now, we didn’t see that one in advance. That was the 2013 explosion over Chelyabinsk in Russia. As you saw in our car video right there, as we saw those dash cam videos, that one was not discovered because it came from. It came out of the sun, came from the direction of the sun. Had it B been coming from the other direction. It was big enough to have been discovered in advance. Whether or not it would have been discovered in advance. We don’t know because our surveys are not optimized for such small objects. But objects of that size are being discovered all the time. There are millions of those literally millions. So we can’t discover those far in advance because once, you know, if they’re if they’re very far away at all, they’re not bright enough to see. 

So what what sort of warning time could we get on something that small? 

Well, it depends on how we optimize our surveys or optimize more for discovering the big ones that are farther away. If you were actually trying if you were specifically looking for those, you could easily have a week’s notice for something of that size. That’s possible. And I’ve argued that we should be doing that for for multiple reasons. I mean, in that case, in the case of Chelyabinsk, you know, if that had been discovered and we can advance, we could have issued a warning, very much like a hurricane warning. If you’re outside the red zone, maybe take cover. If you’re inside the red zone, evacuate. We wouldn’t have known exactly how big it was because that takes more information than just measuring the brightness, because the brightness can depend on the albedo or the reflectivity as well as the diameter. And we wouldn’t necessarily have known how how dense it was either or how it would break up in the atmosphere and how deep it would go before it exploded. So there’s all sorts of. There would be all sorts of uncertainty associated with it, just like there is for a hurricane or a tornado. 

I mean, just because, honestly, the odds of the tornado hitting your house is pretty low. Doesn’t mean you don’t go in the basement. 

Yeah. You know, in Chelyabinsk, thousands of people are more than a thousand people were injured, some quite seriously. Some had to be taken to the emergency room. And most of those injuries were flying glass. So if you had advance warning, you could tell people, you know, to go to the window. You know, duck and cover, take cover away from exterior windows. The same thing you tell people for tornadoes. 

And you can even board up windows in advance and, you know, reduce the millions of many millions of rubles of damage that was done. 

I mean, they had to replace a lot of windows. 

That a sonic boom or a shockwave that’s breaking all those wind? 

Well, a sonic boom is a shockwave. And so it technically it is. I mean, it. 

So a sonic boom we associate with this a shockwave that’s generated by something that’s moving at supersonic speed, which an incoming meteor is. But this one is also reinforced by the explosion. 

So it’s a combination of a sonic boom and an explosion shock. 

So really, the shockwave, the air blast from an explosion locally is indistinguishable from their air blast from a sonic boom. 

But we call it a sonic boom if it comes from something that’s supersonic. My science background is suspect, but. 

A sonic boom. 

Something’s racing through the air so fast that the air claps together behind it or what is a smell? 

No, it’s more like I mean, it’s easier to think about, like a wake that’s made by a boat. So if you’re me, if you’re writing, if you’re waterskiing behind a motorboat and a motor boat is moving faster than the speed of the wave on the surface of the lake, then you get this. This bout wave and it’s called a ball away because it’s created by the bow of the boat. And the same is true with a sound wave in the air. If something is moving faster than the sound speed in the air, it creates about shock. So it’s it’s very similar physics. And so you kind of get this cone shaped shockwave to compress it. 

It’s a very sharp compression and an expansion. 

And then, you know, you have a space behind a wake, which is like the space behind the motorboat that you waterski in. And then you can go over. You can ski over the jump over the way you can. Things like that. And it’s very similar. But in. The boat wake is kind of like a two dimensional. It’s on a two dimensional surface and bough shock is really in three dimensions. So it’s a Sirpa. It’s a two dimensional surface within a three dimensional space. 

But that and that’s that happens in air. It doesn’t happen in space. 

No, it doesn’t happen in space. Because you need a sound. You need a mat. You need a medium. Yeah. 

Yeah. Because I was thinking, wow, that would be cool to be able to draft behind a comet like a truck on the highway. 

You know, I should I should revisit that because you do get bad shocks in space. I mean, the earth actually creates about shock in the solar wind. The solar wind is a medium. And so the earth, as it moves through space, its magnetosphere actually displaces the solar wind and creates something that looks just like a ball shock. Wow. So they talk about that. But it’s not you know, it’s it’s it’s something that can be measured. 

But the you know, the the medium is very, very low density. 

Yes. So that it wouldn’t help you. I mean, I know that we ride the solar wind in some ways going away from yes on. You can use it as a sail. 

Yeah. People have talked about spacecraft that are driven by the solar wind. Like a sailboat. They’re using that that way. 

Well, it’s it’s really just a flux. So it is like wind. 

It’s a bunch of science coming out of the sun and they’re streaming out into space and and they carry mass and momentum. 

And so as that mass interacts with surface, it can push on that surface. And so if you have a very large surface area and very low density, you can actually use it to accelerate that surface. 

So if you got behind a planet heading toward the sun, that might give you a little bit of break from the solar wind. If you. 

You’d be you could be kind of in the shadow of the earth. So so behind that ball shot. So the earth does create about shock. And then behind the earth, you have a lower density of these ions. Any plan it would would create any current planet with a magnetosphere. 

Wow. It’s all the stuff is so fun to think about. 

Is there a definition between when does something become large enough to be an ass? 

Well, there are all these definitions and that’s just what they are as definitions. 

I mean, it’s just the words we’ve chosen to use to describe these things. And also, they have sort of some historical we you know, we can trace the etymology back to some history of where, you know, the word meteor we now associate with an incoming object from space. But when the term was first coined. People didn’t know what they were. They saw this shooting stars splashes in the sky. And that weird meteor really has to do with the atmosphere. And so a meteorite is then the thing we pick up off the ground makes it all the way. It makes it all the way in. And then people use the term meteoroid for to mean an asteroid that’s smaller than a meter or so in diameter and above a meter in diameter. It’s called an asteroid. But the term asteroid was coined as an astronomical term observing point like objects that are moving differently than stars. So asteroids, sort of the the literal definition is starlight. Right. 

Aster Seastar and oit is kind of like. So it looked kind of like a star, but it didn’t. It moved against a field of stars and one big enough to be a planet. So it’s like, what’s that thing? I don’t know. Let’s call it an asteroid. And then as we studied more, we realized they were just big space rocks. 

And then a calm and the word comment while those were observed by the ancients. So that’s a very old word. And it had to do with something fuzzy in the sky. So technically, you a lot of these words come from as observational terms. We don’t know what we’re looking at, but we’re going to call it this. And eventually we figured out what it was and we still call him that. But then we realized, oh, well, there’s not a really distinct dividing line between one thing and another. 

And we retain you know, we retain the words that we originally used when we didn’t know what we were talking about, just as we just we just saw something. We didn’t know what it was. And we call it by name. Where do they come from? Most of them. 

Asteroids. Yeah, there they are. So most of the asteroid during the main belt, which is between Mars and Jupiter and hyperbolic, you know, the Kuiper Belt, this is further out. And that’s really mostly comets. So the further out you go, the colder it is, as matter condensed from the solar nebula. So there was a big nebula, the sun and the planets condensed from through a sequence. And the highest temperature condensing stuff condensed out first. And that stuff tends to be closer to where the sun formed. 


Lower materials with lower condensation, temperatures tend to condense further out, so you have volatile stuff. The farther out you go, the more volatiles you have. And the closer and the more rocky silicate metal type stuff that you have. And so a lot of people think of the asteroid belt as being kind of a failed planet formation. There could have been a small planet that formed there, but it just didn’t get it together and coalesce here enough. 

Do you think any of that stuff is. 

Clumping up on a regular basis. I mean, are there planets still forming? 

No. No, they’re just the dynamics. Doesn’t doesn’t really make that possible. I mean, the the the solar system is in a very stable configuration now. It evolves very slowly. But the planet all formed, you know. 

Something like four and a half million years ago. 

And that kind of everything kind of formed into these planet testimonies, which are created and collided with one another and created these big planets. There were some big events towards the very end of that. A lot of people. And it’s pretty much widely accepted now that the moon, the earth’s moon was formed by a collision between the proto earth and a very large Mars sized planet, Tassimo. That created a big vapor cloud that condensed and formed the moon. 

Not not as an impact. 

Yeah. There are very large and powerful giant and the giant impact hypothesis for the moon. 

But we could have been so, so much bigger if it weren’t for that. 

And will you add. Yeah, so. So if you add the mass of Mars to the mass of something’s a little bit smaller than the Earth, you get something, I guess, about the size of the earth. And the moon is very, you know, very small fraction size of the earth. 


In terms of mass, do you think we should be going back to the moon manned missions to the woman missions. Maybe it’s time for a woman on the moon. 

Well, yeah. I mean, of course it is. I mean, it’s been what’s the last Apollo 17 was in? 

I think quick time out here. Apollo 17 happened in December of 1972. The astronauts were Eugene Cernan, Ronald Evans and Harrison Schmitt. It was the only night launch of the program and it featured the first geologist on the moon. It was the last Apollo flight. And the last manned moon landing. Cernan and Schmitt stayed on the surface for just over three days and spent just over twenty three hours of time in extra vehicular activity. 

The Apollo program. 

Went really fast. So I just saw the first man on the moon and it was six July of sixty nine, there were planned to be more ammunitions, but it was Apollo eleven through Apollo 17. Twelve men walked on the moon. Apollo 13 didn’t make it was 13 the last one. No. 17 was the last 13. Yeah. 13 was the one that failed. And they made us swing around the moon and came back. 

Amazing how I knew exactly what was going to happen in that movie. And it was still kind of gripping. Right. 

I think it does make sense in my in my mind, it does make sense to go back to the moon and do something a little bit more permanent. 

Still things to be learned there. 

And, yeah, I think there’s a lot to do. And I think we can kind of think of it as a stepping stone to Mars and Venus. 

We’re tracking these larger asteroids. The buzzer goes off and someone says it’s on its way. 

What are the potential actions we can take to destroy it or steer it away? 

Great question. Well, we know something’s already on the way. 

I mean, that’s and we know lots of things are already on the way. We just don’t know which ones, when or where or how long. The survey program is to find the ones that are on the way and find them early enough where we have time to actually deflect them. 

And if you have enough time in a decade or more, you don’t have to change its course very much to cause it to miss. So. So the strategy really is to speed it up or slow it down just a little bit. So you’re not actually changing its trajectory very much, but you’re changing its speed along that trajectory just by a little bit, you know, centimeters per second. 

That’s like a pursuit route with this low ball player. If you speed up or slow down a little bit, you miss him. 

It’s very much like that. Or it’s like a collision at an intersection, avoiding a collision through an intersection. You don’t swerve. You either slam on your brakes or in or maybe you’re going to step on the gas to get through before you get t boned. Second could make all that. It can make all the difference. And, you know, if you had you know, if you had time to think about it, you would know whether it’s better to step on the gas or touch the brake pedal. And you don’t have to do it that much. I mean, if if if that if the two objects colliding are moving very fast, just a little bit, a change of speed is enough to avoid a collision. And that’s really what you want to do. But you look because the object, if it’s one of these one kilometer or hundreds of meter diameter objects, that’s a huge mass. 

And so even a little bit of speed requires a lot of energy, a little bit of Delta G, a little bit of change in velocity requires a lot of energy. 

And depending on how much time you have, you know, if you have a lot of time, the Delta V doesn’t need to be as big, you don’t need as much energy and you have more time to plan. 

And you might be able to do it just by doing a billiard ball type collision. You know, really, it’s much faster than a billiard ball. It doesn’t just bump it and accelerate it. You actually make a crater. You create an impact like the one we were talking about, that deep impact experiment. And the ejecta actually pushes like a little rocket engine and you can change the speed and cause it to miss. So the real key. One of the founders and leaders of planetary defense, we call ourselves the Planetary Defenders, Don Yeomans from the Jet Propulsion Lab had three three rules for planetary defense. Find them early, find them early and find them early. If you don’t find them with enough time to do something, it doesn’t matter. You know, you’re too late. 

So that’s why the most important thing to do is to keep these surveys going and find anything that might be on a collision course with the kind of time horizon that’s near enough into the future that we would actually do something about it. 

But far enough into the future where we would actually have time to do something about it. Are any other countries doing the survey or is it just us? It’s an international effort, but primarily most of the surveys are funded by NASA. Catalina Sky survey, parents, stars, other other telescopes, other surveys. But no, it’s it’s definitely an international effort. 

Find it early, find it early, find it early and found it early. Now, what do we have any of those bullets to shoot at it? 

Well, we have we we pretty much know how to do it. We modeled it. We know. 

There’s a lot of uncertainty, which means, you know, like it with any big engineering design problem, you over engineer everything, but no nothing. We know how to launch rockets, but we don’t have rockets specifically for this task. And we have guidance systems. We’ve actually done the Deep Impact experiment. We know how to hit comets. So so we really know how to do it. But engineering to a specific threat hasn’t been done. So that’s why one of the reasons you have to find it early, because there’s really nothing to push us to do that unless there’s a very specific threat. 

Yeah, well, I mean, there we know this is going to happen eventually, someday. So. All right. I mean, if the world’s governments were smart, we’d have something a little bit more in place. Yeah, I would. 

Well, yeah. I mean, you can you know, I kind of make the argument the other way for a marginal cost, you know, for if somebody gave you a hundred million dollars and said, spend it on planetary defense, what would be the smartest way to spend it? 

And in my opinion, the smartest way to spin it would be to build more telescopes. Right. Cause either you’re going to find something or you’re not. And if if if you max out your survey capability and you don’t find anything. Well, it would have been a waste of money to, you know, build a rocket and, you know, build the capability to deflect something because there’s nothing to deflect. 

And if you do find something, you’ll get more money. 

I guarantee you. Yeah, they’ll come up with the money. Yeah. So. So I think, you know, just from an investment perspective or a kind of optimization, you’d be smarter to spend extra money on more service. Start out by which I probably shouldn’t say because I’m not. That’s not the part I’m in. I’m in the part of designing how to do it. So, you know, I would like to have a little bit of that money to go to war simulations and experiment. 


And then the last question is if. If we miss it and it’s on its way. 

What are. Paint the picture. If it hits, if a what’s an average size asteroid? 

Well, yeah, you can’t really say such a thing because you’ve got this parallel distribution. So, you know, I guess Averitt and then you’ve got this arbitrary cut off at one meter bewitch below, which you don’t call asteroids anymore. You call it meteoroid. So it’s sort of saying the average size is sort of arbitrarily different. But that said, because there’s a power law distribution, the by far the most likely dangerous impact, the next impact that’s going to hurt somebody is going to be a very Chelyabinsk like event that we with our current survey capability. There’s a really good chance we won’t see it coming either. It’ll be a Tongo Scarra Chelyabinsk type event. 

So but those are just the things. 

I mean, just I mean, that’s horrible. Killed lot of people and hurt a lot more people. 

But really, the ones that are, you know, the size of a house are bigger that make it all the way in there when that hits one of the oceans, which is the most likely scenario. Right. It’s an ocean there and causes, what, a big wave. 

How sized object hitting the ocean isn’t going to really do much. 

Now. It’ll it’ll you know, as long as there’s nobody in the vicinity, you know, will. Well, it’ll make a big explosion. And our instruments, you know, it’ll make an infrasound wave that detectors will hear around the world. 

Would the ocean water only stop it from getting to the bottom of it? Well, depends on it depends. 

I mean, it depends on how it’s like the answer to a lot of these question. It depends it depends on how fast it is when it hits the water. If it had slowed down through the atmosphere, but hasn’t vapor all vaporize, it’ll hit the water, you know, at a speed that won’t cause it to vaporize. 

It won’t cause an explosion. And then that’s a meteorite and it’ll sink to the bottom. And there’s lots of meteorites at the bottom of the ocean from that happening because it’s happened many, many times. Yeah. We don’t really think about that much, do we? Are all focused on the land. 

But getting back to your question, you know, what would we do if we missed it? 

That’s I would argue, OK, that’s one reason you find them early. 

And that’s one reason why you overengineer you assume that there’s some small probability that the first time you try it isn’t going to work. And so you better have a backup plan. I mean, in space space exploration, we always have redundancy, especially in human space exploration. And so this is you wink’s people’s lives, dippenaar, as they would in this case. You have multiple layers of redundancy, and that’s one reason you find it early. It’s probably more likely that we’re gonna get hit by something that we don’t have time to deflect. And we either make we we discover it with not enough time to deflect or we don’t discover it at all or, you know, just at the very last minute, in which case. It’s really a civil defense problem. It’s more like the hurricane evacuation problem and or the batten down the hatches. Duck and cover type option. And in my opinion, just based on this sort of probability, when you have a power loss size distribution, that’s by far the most likely thing to happen. And we do we have thought about that. And we actually have had these tabletop exercises with DEMA. And also at our biannual planetary defense conference where we come up with scenarios and then we talk about what would happen if. Something were to hit and we had a failed deflection. You know, how do we inform people and what measures do we take? 

But something like the size of the meteor crater, it yeah, that’s not something you could even deflect if that’s a dense object that comes all the way in there and hits Manhattan. Right. You’re not going to have that much time. And it’s still going to do a tremendous amount of damage. 

Yeah. With, you know, 30 or 40 meter diameter iron object, you’re not going to probably find that in advance. 

I mean, there literally are millions of objects that size in the vicinity of Earth, Neurath objects of that size. And and so it will be, you know, assuming we did have millions and millions of dollars for a survey program. It would still be decades before we could even make a dent in discovering all of those. So it’s unlikely that we would see one of those coming very far in advance and we wouldn’t be taking the hit. 

And if it happened to be hitting Manhattan. 

You know, that would be like worse than Superstorm Sandy, you know? But you’d have to get people out of there. 

But fortunately, population density is such that hitting a high dense population density part of the earth is also another layer of very low probability. And at some point, you kind of have to depend on low probability. 

You know, you what you want to focus. 

You don’t want to focus all your resources on events that are extremely unlikely. 

Spoken like a true scientist. Well, I mean, that’s the reality of it. It doesn’t. It doesn’t it sort of doesn’t sound very nice. But I mean, we just drove back from between here and Las Vegas and, you know, ninety nine point nine percent of that land is empty. And and the oceans are empty mostly. And so that’s most of the earth is still a pretty, pretty non pop. 

Yeah. Yeah. Population is not distributed very homogeneously. 

Yeah. So we’re getting across thinner. And we’re not the center for Inquiry doesn’t believe in crossing your fingers per say. Yeah. The odds are a little on our side. 

But again, I mean if you have we have limited resources. Yeah. And we can do kind of a cost benefit analysis. 

And you know, if you have so many dollars to spend on saving lives or preventing people from dying. Where do you spend it? 

And spending it on super low probability events is probably not the best use, especially in wealthy Western societies. 

I mean, there’s no shortage of gaming boards and all kinds of stupid things that we, in my opinion, stupid, that we spend our money on. 

And people can come up with, you know, a thousand bucks to go see Paul Simon play at the Hollywood Bowl or whatever. 

And we don’t want to spend a buck a year apiece or whatever it is to do something like this, which may save the planet. 

That’s true. But I can probably come up with thousands of low probability things that you could spend a buck on each one. 

And now all of a sudden, you’re spending thousands of dollars on thousands of super low probability things. 

Shark attacks, hatches and. 

Yeah, I mean, so still, it’s kind of the same problem. I mean, we’re talking about one, you know, an asteroid hitting Manhattan, super low probability. 

I can calculate it, maybe not in my head right now, but it’s super low probability, you know. But we have done this sort of risk analysis, this sort of probabilistic risk assessment. 

And we can come up with an average number of people killed per year over the long run. You know, given given the current rate of impacts, you know, every ten thousand years, there might be an event that kills a million people every 10000 years. Well, that’s like one hundred people a year on average risk, which is nothing compared to people. The number of people who who who die from automobile accidents or smoking or malaria or malnutrition or climate change or even or slip and fall in their bathtub. 

Right. I mean. Exactly. It’s so. 

So, again, you know, you you got to apportion your resources for it. What do you maximize or what do you what do you what it is it you’re actually trying to optimize minimize the number of average deaths in the long run per year? 

Well, maybe not. You know, maybe you want to minimize the. 

Event that kills a million people, even if that only happens once every 10000 years on average. 

And the way the Russians are going, they’ve been getting most of the hits lately anyway, so. 

Yeah, of course. Well, it’s our turn. 

You can tell it’s our turn. We do. OK, we both. We all know that it doesn’t work that way. 

I know. We’re joking. Well, this has been fascinating. 

I don’t know if I feel I I guess I do feel a little bit better about dying in an asteroid impact because it’s probably not going to happen. 

It’s probably not going to happen. But if it did happen, I mean, what would you rather go? 

Yeah. So what was that one movie where the moon is going to impact the Earth and there’s for some reason the orbit was. Degrading. 

And so, you know, one of the guys answers was to just like get himself a scotch and a cigar and go sit on the beach and you’re going to die anyway. You might as well get a front seat. 

Yeah, I can see that. I mean, we’re all going to die anyway. Yeah. I don’t know what’s going to get us. 

Yeah. Might be. Well, I guess I would want all of humanity to go. But be cool to have it be an interesting death then. 

Well I do think I mean, you know, these risk assessment, the kind of thing that I do where, you know, I guess I calculate, you know, 100, 100 deaths per year on average over the long run. It does neglect the value of humanity and civilization. And, you know, everything we’ve ever known or will know and all our science and all our libraries and all our art museums. 

And, you know, if that’s way worse, that’s way worth way more than the sum of all the people. 

I mean, maybe that doesn’t sound like a good thing to say, but I do think civilization is in culture is worth more than all of us put together. 

But part of the value of of each and every one of us is protecting that and contributing to it. 

Right. And that’s what this work is all about. Right. 

Mark Boswell, thank you so much for your work. Keep the asteroids away from us. 

I’ll try and let us know if there’s anything we can do to help. Well, I just think CSI does a great job keeping people informed. 

And, you know, making sure people are scientifically literate and skeptical about things they shouldn’t be skeptical about. Thanks so much for speaking. Thank you. 

Thank you for listening. Point of Inquiry is a production of the Center for Inquiry. 

The Center for Inquiry is a five or one, two, three charitable nonprofit organization whose vision is a world in which evidence signed into compassion rather than superstition, pseudoscience or prejudice guide public policy. You can visit us at point of inquiry dot OAG. There you can listen to all of piecewise archived episodes and support the show by clicking. The blue support button on the site were available on iTunes, Google Play, Spotify and your favorite podcast app of choice. Special thanks to Pamela Crosslin of Crosslin Law, located in The Miracle Mile in Los Angeles. She does business and intellectual property law and helped us out with some of the valuable intellectual property information for this program. Thank you. And see you again in two weeks. 

Jim Underdown

Jim Underdown

Jim Underdown is executive director of Center for Inquiry–Los Angeles, and the founder of the Independent Investigations Group.