Lithopanspermia explained: life traveling rock-to-rock

4:30Something like 14,000 times the atmospheric pressure on Earth. >> Okay. Um substantial survival even at really, really high pressures even beyond that. And the conclusion here is basically that the initial pressure shock that you get from an asteroid banging into a planet that has life and ejecting that planet out, that initial pressure shock that we used to think would completely kill any living organism is actually not that bad. Stuff will survive and go into outer space. >> Mhm. Okay? Now, why does it matter? Well, very recently, we've had the NASA Perseverance rover announce a discovery

5:11of potential life on Mars. Yes. >> We covered this in last year's podcasts. Now, finding that life requires determining the origin of that life, right? And if this is true, well, then we can start asking questions like, well, is that life coming from Earth or is it originated in Mars originally? Mhm. Um this paper sort of shapes that interpretation. It's also got some impacts when it comes to like planetary protection because now, if we know that life actually survives impacts, goes into outer space, and comes to Earth, like we You to be a bit careful about returning samples onto Earth. Because if we bring something back and it's got a little,

5:52you know, thingy thingy in it, we don't we don't want that. >> Yeah, and there's like plenty of science fiction movies about that, about how it can go really, really wrong. Hollywood has its ways of, you know, aggrandizing things, but it turns out it might actually be a real phenomenon. >> Very interesting. So, as always, let's start with the history. This is actually an ancient idea. The Greek philosopher Anaxag Anaxagoras. Okay, like kind of like Pythagoras, but Anaxagoras. Maybe that's how you say it. Anaxagoras, 5th century BCE. He actually is one of the first guys to correctly interpret what the solar eclipse was. Like the moon is going in

6:33front of the sun. He was the first guy to do that, 5th century BCE, so 2,500 years ago. He proposed the idea of spermata, which is seeds of life that are scattered throughout the universe. Now, the Greeks had a very rudimentary understanding of what the universe was, but I still think it's it's quite cool that somebody that far ago was, you know, coming up with these kinds of ideas. The historical basis for the idea of panspermia really comes from William Thompson in the 1870s. This is Lord Kelvin. >> Lord Kelvin. >> Yes. He proposed the scattering of life seeds via like catastrophic collisions. This idea that we had now have of like

7:14stuff going in, collisions uproot material into space and then that material comes into Earth. And then in 1903 there was this guy Svante Arrhenius. I think any chemist in the audience would know about the Arrhenius equation and all the great things that Svante Arrhenius did. But one of the things that he formalized was this idea of radio panspermia, which is the idea that microbial spores, which are small enough, at that time they had figured out how small in mass these these microbial spores were, they could be propelled by the pressure of light Mhm. to move across space. And so that was his idea, radio panspermia. Now, in the 1900s,

7:55this idea was completely invalidated because in deep space we now know, we didn't know about radiation back when Arrhenius came up with his thing, but now we know about cosmic rays and the solar wind and all the radiation and the dangers in space. So everyone was like, "Okay, unshielded deep space, you're going to have ultraviolet radiation, you're going to have this vacuum, it's rapidly going to sterilize DNA, so there's no hope." Right? >> Yes. Then, we started discovering stuff that could actually survive that. In 1956, Arthur W. Anderson discovers Deinococcus radiodurans. This is our Conan the Bacterium. >> I see. Okay? This is the bacterium that

8:37will survive anything. Okay. He was actually at the Oregon Agricultural College and he was studying canned meat that he was trying to sterilize with gamma radiation. Gamma radiation is extremely short-wavelength radiation, extremely high-energy photons, and so that should just kill anything. It should break every chemical bond known. And these and the the meat that he was studying spoiled anyway. And it didn't make any sense, right? It's like you put it into a freezer or like a you put it into Chernobyl and the meat still spoiled. So there's something that grew in it. And when he isolated that, he came up with this bacterium called Deinococcus

9:18radiodurans. Um in the 1970s, there was also the discovery of hydrothermal vents. Yes. >> now you have life thriving in total darkness, 400° C, like way above boiling. It's still water because the pressure is so high. But then again, the pressure is so high and life is still thriving. >> Yes. So, it's very weird, right? And over the following decades, we've had an incredible catalog of extreme environments where life thrives. We have things called acidophiles, which are life that live in sulfuric acid. >> They literally live in sulfuric acid at a pH near zero, which is worse than

9:58bleach, but they're just like living there. Hyperthermophiles that live up to 122° C. The record holder is something called Methanopyrus kandleri. Kandler? Dude, 122° C is insane. I I I Right? Again, high pressure, which is why the water isn't boiling. Water usually boils at 100° C at sea level, but if you do it high pressure, the water's not going to boil. That's why a pressure cooker works, right? >> That That makes sense. >> Um A lot of really really crazy things. Halophiles in in They flourish in salt concentrations that are five times that of seawater. You can see this in the Dead Sea and You can also see this in Halo players who eat a lot of Doritos and chips and Ruffles. Halophiles as

10:40those who might not know. I used to be a halophile in in high school. >> Mate, I I Let me tell you something. Halo 2 and Halo 3 in Oh, yeah. >> No competition. >> No competition. >> Like I It was very serious. Oh my gosh, dude. It was very serious. It's one of the only games >> Blood Gulch? Like what? And and I remember it was back in the day when like there wasn't really internet to host these collaborative parties. So, you had to go to your friend's house and I remember I in the valley there was a a friend's house that I used to go to and he had a TV in one room and a TV in another room and we used to do like co-op. So, four four versus four. Oh my

11:20gosh. LAN parties. >> LAN parties? Before Xbox Connect, before Xbox Live. We'll go back to the story, but this is our history. So, we will give it the due respect. Yeah. Halo raised so many so many millennials in that era. >> Yes, and we are one of them. Halo files. Yeah. Um, in this case it means salt, but for us it means something totally different. So, effectively there's a lot of extreme environments that life thrives in. Right like >> So, now it's no longer the case that like life needs this like perfect setting. The Goldilocks >> Yeah, the Goldilocks stuff, right? Yeah. >> And um, one one of the big things was in

12:021996 Bill Clinton announced possible ancient Martian microbial life in a meteorite that they found in Antarctica in 1984. I I have to ask because you did such a good job uh with the JFK impression, if you could if you could do the voice. >> he goes he goes he goes I did not find life, but I think we found it. But, I did not have sexual relations Anyways, there was a meteorite in Antarctica. They found possible ancient life on it. It was published in science. Immediately everyone was like no. Immediately no. Immediately no. Like, it

12:43was largely refuted, but the rock transfer, the fact that that meteorite came from Mars is actually not disputed. Meaning meaning that that the origin on Google Maps its original starting point >> is Mars. >> is Mars. >> Not Not everyone's fine with. >> Okay. The fact that there's life on that meteorite, that's what everyone's not fine with, okay? They they saw little structures that kind of looked like bacteria and so on and so forth. They didn't have enough evidence, but it really started this question of could life survive the journey Right. >> from Mars to Earth. >> Because now we have evidence that it can happen. >> That it can happen. We definitely found a Martian meteorite, and you know, it looks like there's some weird stuff on there. And so, that gets us to this