The Most Promising Alien Planet We've Ever Found?

0:28This episode is brought to you by Google Chrome. and not too cold, so you can get liquid water on the surface. And it is planets in this zone that astronomers are especially interested in, because those are more likely to have life. And for the first time, we've detected an atmosphere on one. Also, scientists have detected sugar molecules in interstellar space for the first time. Both of these results are a big deal in the search for alien life, and that's what we're getting into today on The World, the Universe, and Us. I'm Senior Editor Chelsea White, joined by space reporter Leah Crane. Hi, Leah.

0:58Hello. So first things first, where is this planet? So the planet is called LHS 1140b, and it orbits a small and cool type of star called an M-dwarf, and it's about 50 light years away. Okay, so take us through why it's so interesting. You know, we've found atmospheres on lots of planets, right? So why is this such a big deal? So we found atmospheres mostly on gas giants or on really hot planets. So really big and really hot, but we've never found one on a planet that's both small enough to be rocky and cool enough to retain liquid water on its surface. And this one is both. So that's why it's important.

1:35Well, it's almost surprising to me that we haven't detected atmospheres on smaller planets in any of the planetary systems near us. Why haven't we done this before? So we look at these atmospheres using the transit method, which is where we look for dips in a star's light, where the planet goes in between the star and us and blocks out a little bit of the light. that's a lot easier when the planet is really big, so that dip is really deep. Or it's really close, which makes the dip deeper and also makes it happen more often. So when something's small or far away, it's much harder to spot, even if it is there.

2:08So then what is this method able to tell us about this atmosphere? What do we actually know about it? We know very little. We've spotted some helium that seems to be flowing off the planet out of its atmosphere, But there aren't any observations of the bulk atmosphere that have been published yet, although I hear some have already been taken with the James Webb Space Telescope. So we don't know anything about this atmosphere, really, except it's got some helium in its upper parts. Well, that's tantalizing. I can't wait to hear about those results when they get published. So that means that this could be what's called a helium world.

2:45Is that right? I hadn't heard of that before. What are those? So they're a type of planet that's been theorized, but never spotted for sure before. And it's sort of in between a super Earth and a mini Neptune. So it is a rocky planet, but it has this really thick, heavy helium atmosphere on it, which means that the surface is at a really high pressure. And they're still potentially interesting for life. Things live at high pressures on Earth, but they are very different from anything we have in our own solar system. That is what I was going to ask you about. It sounds like it would have to be a very different kind of life than we've got.

3:21Is that right? Yeah, probably. We don't know how thick this atmosphere is, so we can't say that for sure. But it is very possibly the best place we know of to look for life at this point, now that we know it almost definitely has an atmosphere. Well, you said almost definitely. Why not definitely? Yeah, I thought you might catch that. So they first spotted this signal of this atmosphere in 2024. And they observed this planet again in 2025 and did not spot anything. So they sort of went back and poured over all of the data and it stood up. Signal in 2024, none in 2025. Which is weird. There are a bunch of ways to explain it.

4:06It may just be that the environment around the star has changed. and that can change the state of the helium. But either way, this is for now the most secure detection of an atmosphere on a rocky planet. And it's almost definitely there, but it would be nice to confirm it with JWST or some other observatory. Do we have any idea of what this planet might be like outside of just its atmosphere? Is it possibly like Earth is the question everyone wants to know? It is definitely not an Earth twin. I think if I was going to compare it to anything in the solar system, it would probably be the icy moons like Titan or maybe Enceladus.

4:46Okay. You know I'm a big fan of those. Yeah, they're pretty good. Because we haven't observed the bulk atmosphere, just this helium outflow, but we have observed the density of the planet. We know that it either has a whole lot of atmosphere or a whole lot of water. and those two options are really different for what the surface looks like. So it might be a really high pressure under that atmosphere, like I was saying earlier, or it could be completely covered in water, but with a normal pressure atmosphere or basically anywhere in between. We really just need more observations to know. Right.

5:18And will we be taking more observations, I hope? Definitely. This was already an interesting planet before this paper came out, and now it's going to shoot to the top of a lot of lists. Like I said, there's already been some observations taken. There will now be a lot of people looking at it trying to confirm this atmosphere and learn more about it and see if it might actually be habitable. So definitely, there will be more observations. So you said it was 50 light years away, which feels too far to get to, but quite close to look at, relatively speaking. So we should be able to learn a lot more, right?

5:52And what about those planets much closer to us? It's kind of surprising to me that there aren't that many star systems within 50 light years. So it's not like there's millions of planets to search through, right? Yeah, I mean, there's a lot of planets, but it's not like a huge, you know, grains of sand on the beach number for the ones that are close enough to actually get a good look at. Let's take a short break. Technologies like AI are increasing the number of drug candidates entering development. But there's a challenge. Manufacturing capabilities have not kept pace with discovery. As new molecules become more diverse and complex, purification at scale is becoming increasingly difficult, meaning many promising treatments risk falling by the wayside.

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7:13That's Indeed.com slash podcast. Terms and conditions apply. Need a hiring hero? This is a job for Indeed Sponsored Jobs. Well, speaking of newly discovered exoplanets, there was a post recently by Avi Loeb, the astronomer from Harvard, talking about a newly confirmed rocky exoplanet that's just 25 light years away from Earth, so half the distance. And that planet doesn't transit its star, like you were saying. So at the moment, we don't know if it has an atmosphere, but it is in the Goldilocks zone. And Avi suggests it might be habitable. What do you make of that? I think it's great to have a planet in the Goldilocks zone or the habitable zone, as researchers call it.

7:54But we know of quite a few rocky exoplanets in the habitable zone around their star. And if it doesn't transit, it's hard for us to even look for an atmosphere on it. So I would say it's probably not one of the very most promising planets just because it'll be so hard to actually see if there's an atmosphere there. And we need it to be in the habitable zone and have an atmosphere in order to have water on its surface, which we think is really necessary for life. Well, I want to speak about another discovery, which is also about the ingredients for life. This is the finding that there were sugar molecules in interstellar space for the first time.

8:37This is sugar detected in a cosmic cloud nearly 27 light years away. Yeah, so this is a cloud that we already knew had a whole bunch of organic molecules, including glycoaldehyde, which is a compound that's involved in the formation of sugars, but it's not considered a true sugar itself. So it's not necessarily surprising, but it is still very cool. And astronomers, when they looked at the light from this cloud, they can see the spectral fingerprints of sugar made from four carbon atoms called erythrolose, which is one of the sugars found in raspberries. Yeah, the team suggests that erythrolose may have formed before the solar system itself and then become trapped inside asteroids and comets as they formed and finally got to the young Earth billions of years ago.

9:23And that process could have delivered the equivalent of 500 ,000 to 50 million tons of erythrolose to the young Earth. So maybe young Earth, you know, smelled like raspberries, tasted like raspberries. That's a huge amount of sugar. And that makes this a really sweet cosmic cloud. And it's also a stellar nursery, right? This is where stars are born. Yeah. So that's why the researchers suggest there's a link between us finding these organic compounds in these clouds out in space and getting them onto planets as they form, which is the part that is important for potentially prebiotic chemistry. That's all for this episode.

10:00Thanks to our guest, Leah Crane. And thanks to you for listening. Bye.

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