Did Scientists Find Alien Life Or Just Controversy?

Recently, a group of scientists claimed they found possible signs of life on a planet called K2-18b. The news made headlines. Researchers said they'd detected sulphur-based gases that, on Earth, are strongly associated with life. But the research caused an uproar in astronomy circles because other scientists don't think the data is strong enough to celebrate an alien find just yet. In fact, they have some real issues with how this whole thing went down, and a new analysis casts further doubt on the findings. NPR science correspondent Nell Greenfieldboyce https://www.npr.org/people/4494969/nell-greenfieldboyce is here to wade into the controversy — and tell us what all this means for the future of searching for life beyond our solar system. Want to hear more about new science research? Let us know by emailing [email protected] mailto:[email protected]. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave http://plus.npr.org/shortwave. See pcm.adswizz.com https://pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. NPR Privacy Policy https://www.npr.org/about-npr/179878450/privacy-policy

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• 0:00Speaker 00

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• 0:20Regina Barber?

  Hello, fellow Earthlings. Regina Barber here. And today, we're going to talk about some recent science news that made a big splash. The claims that possible signs of life have been found on a planet called K218b. This made headlines everywhere, including NPR, where it was reported on by none other than our old pal, Nell Greenfield Boyce. Hey, Nell.

• 0:41Speaker 02

  Hey there.

• 0:41Regina Barber?

  So, Nell, this was new research done with the James Webb Space Telescope. And basically, researchers said that they detected a couple of sulfur-based gases that on Earth are strongly associated with life, such as marine microbes.

• 0:54Speaker 02

  That's right, like phytoplankton. So, think alien phytoplankton.

• 0:58Regina Barber?

  So cool.

• 0:58Speaker 02

  The researchers said this planet could be an ocean world, just teeming with life. A press release called their results, quote, "The strongest evidence yet that life may exist on a planet outside our solar system."

• 1:10Regina Barber?

  Yeah, and all of this created quite the uproar in astronomy circles.

• 1:13Speaker 02

  I think some astronomers and planetary scientists were just taken aback at how all this landed in the public's eye. Like, I was talking with Ryan McDonald. He's at the University of Michigan.

• 1:23Speaker 03

  For a lot of astronomers, the very first thing that we heard was a message from a family member or a friend. "Oh, hey, have you heard that aliens have been found?"

• 1:33Speaker 02

  Spoiler alert: he and other astronomers do not think that aliens have been found. And they have some real issues with how this whole thing went down.

• 1:43Regina Barber?

  Today on the show, what happens when a team of scientists claim to have found hints of alien life? We look at what the researchers said, how everyone reacted, and what all this means for the future of searching for life beyond our solar system. You're listening to Short Wave, the science podcast from NPR.

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• 3:30Regina Barber?

  Okay, so now, let's start out with just like some basics about Planet K2-18b. Like, what is this place?

• 3:37Speaker 02

  So it was discovered about a decade ago, and not much is known. So it orbits at a distance from its star that would make it kind of moderate in temperature. So, you know, maybe liquid water is possible there. This planet is bigger than Earth, but smaller than Neptune. And that means we don't really have anything like it in our solar system. So, no one really knows what it's like. And some people think it could be entirely covered in water and ocean world. Other people say, you know, it could be covered in magma.

• 4:06Regina Barber?

  Ooh, this is fascinating. Okay, but how far away is this planet?

• 4:10Speaker 02

  So 124 light years.

• 4:13Regina Barber?

  So that's far.

• 4:14Speaker 02

  It's far, yeah. I mean, in cosmic terms, maybe not, but yeah.

• 4:17Regina Barber?

  Yeah, exactly.

• 4:18Speaker 02

  As far as human terms go, that's far away. And the James Webb Space Telescope can't see the planet itself because the tiny amount of light it reflects is just overwhelmed by that of its closest star. We can only find these planets because we can see their effect on the stars and all the telescope can see is light from that star. So when the planet goes around the star, it passes in front of it, getting between the, you know, the star and the telescope, the starlight changes. Some of the starlight interacts with its atmosphere, kind of filters through the atmosphere.

• 4:49Regina Barber?

  Yeah, so the idea is that you can like analyze the starlight to get clues about the atmosphere and like what gases are inside of it.

• 4:56Speaker 02

  Exactly, yeah. And the gases might tell you something about what's on the planet or what's going on there. And so that's what this team of researchers tried to do. And the work was led by Nikhu Madhusudan. He's at the University of Cambridge, which held a press conference for reporters. And he said what they'd found was just huge.

• 5:15Speaker 05

  These are the first hints we are seeing of an alien world that is possibly inhabited.

• 5:20Regina Barber?

  Wow. I mean, that's, that's a strong statement. Like, what did they find? Like, what were these hints?

• 5:26Speaker 02

  Basically, he said when they analyzed the starlight, they found signals that could come from two related sulfur-based gases, DMS and DMDS. And so these gases are found in Earth's atmosphere because they're produced by life, by microbes. And because these gases on Earth are closely tied to microbes, they've long been seen as potential biosignatures, hints of life.

• 5:48Regina Barber?

  And these like sulfur-based gases aren't made by anything else?

• 5:52Speaker 02

  Well, in the atmosphere, I mean, not that people are aware of, that I know of. I mean, there is some recent work in the laboratory showing that it is possible to produce these gases with no life.

• 6:02Speaker 05

  We cannot, at this stage, make the claim that even if we detect DMS and DMDS, that it is due to life. Let me be very clear about that.

• 6:12Regina Barber?

  Okay.

• 6:12Speaker 02

  He said there needed to be more lab work and more modeling of possible things that like could be going on on this planet that might make this stuff.

• 6:19Regina Barber?

  Like geologic processes or like something that didn't require life?

• 6:22Speaker 02

  Yeah, and he also said the detection itself needed to be confirmed with more telescope observations to make sure that this gas or combination of gases was really there, you know? But even though he made those cautious remarks, overall, he was just extraordinarily enthusiastic.

• 6:39Speaker 05

  Frankly, I think this is the closest we have come to seeing like a feature that we can attribute to life.

• 6:47Speaker 02

  And he said at a personal level, it was like a shock to the system.

• 6:50Speaker 05

  When you're faced with potentially one of the biggest landmarks in the history of science, and I know this, you know, sounds grand, and it's not my intention to make it sound grand, but there is no other way to put it.

• 7:04Regina Barber?

  Yeah, I mean, this would be a huge deal, not just like in the history of like science, but the history of like humanity. But you said other astronomers were a little skeptical.

• 7:13Speaker 02

  Yeah, I mean, it would be a huge deal if it was true. And that if is pretty important. So one of the first people I called up was Laura Kreidberg. She studies planetary atmosphere. She's at the Max Planck Institute for Astronomy in Germany.

• 7:27Speaker 06

  I think this is one of those situations where extraordinary claims require extraordinary evidence, and I'm not sure we're at the extraordinary evidence level yet. I think we need another look to get all the way there.

• 7:40Speaker 02

  Well, let's start at the basics. Do you believe that they have detected these molecules in these quantities?

• 7:46Speaker 06

  Not really. If I'm being straight with you, not really.

• 7:50Regina Barber?

  Wow.

• 7:52Speaker 06

  I think that we are in the very early stages of learning how to interpret the data from the James Webb Space Telescope. It's a tricky business. These are really, really small signals. We've just been at it for a couple of years.

• 8:04Speaker 02

  She says that this kind of measurement is just incredibly, incredibly hard. And, you know, she wasn't the only skeptic. Another astronomer told me he really wouldn't be surprised if the signal just disappeared when people did independent analyses of the data.

• 8:17Regina Barber?

  Oh, wow.

• 8:18Speaker 02

  And then Ryan McDonald, that astronomer from the University of Michigan, quickly wrote up this little critique of the research paper, and he posted it on the Blue Sky's social media site.

• 8:26Speaker 03

  And it gets into super nitty gritty statistics, but the The signal is just not strong enough to say there's anything there in the atmosphere with these observations.

• 8:34Regina Barber?

  So that's a few critics, but like, how did this land overall?

• 8:38Speaker 02

  From what I can tell, there's a general consensus that the strength of the evidence did not warrant the kind of enthusiasm that surrounded it. And, you know, already there's been more than one reanalysis of the data put out there. Like, the first one I saw was from Jake Taylor at the University of Oxford. His study sort of said there's too much noise in the data to reliably find any kind of signal of these gases or anything else for that matter.

• 9:01Regina Barber?

  So what did the original researchers say in response? Like, obviously, they felt like something was there.

• 9:06Speaker 02

  Well, I reached out to a couple of them about Jake Taylor's analysis, and Niku Madhusedan said the model Jake used was too simplistic and not relevant. But Jake, of course, disagrees, saying it's a tool that's commonly used to just kind of quickly check telescope observations to see if there's anything worth following up on. And then there was this other analysis that's just been posted online by another group. It found that numerous other models that don't have biosignatures at all are also compatible with the observations.

• 9:33Regina Barber?

  Oh, wow.

• 9:34Speaker 02

  So, you know, it's not looking good right now, I gotta say.

• 9:37Regina Barber?

  And this is the way, like, science goes. Like, this is gonna go on and on for months.

• 9:40Speaker 02

  Yeah, but, you know, the headlines have already been out there about possible signs of life being detected on another planet. And that really rankles some astronomers, like Ryan McDonald.

• 9:50Speaker 03

  And for many of us, it's felt like damage control, to be honest, because we don't want people to think that the ultimate and most important, one of the most important scientific discoveries potentially this century has kind of already been made, just for it to ultimately turn out not to be true.

• 10:09Speaker 02

  There's been a lot of hand wringing about this whole episode and how to prevent something like this in the future.

• 10:14Regina Barber?

  I mean, like, short of a, like, UFO hovering above Times Square and, like, aliens coming out of it, the discussion about this stuff is going to be contentious, right? I mean, like, this is how science is done. Like, somebody makes a claim, somebody else has to check it to see if it's true or if it can be disproven.

• 10:29Speaker 02

  Sure. I mean, it's not like there haven't been similar episodes in the past.

• 10:32Regina Barber?

  Right.

• 10:33Speaker 02

  Like, what about phosphine in the atmosphere of Venus a few years ago? Do you remember we talked about that one?

• 10:37Regina Barber?

  Yeah, it was very similar, right? Like, it's another gas associated with life that was detected in a planet's atmosphere. It made headlines. And then, like, people debated whether the detection was even real. And if so, like, whether it could have been made by, like, some other process.

• 10:52Speaker 02

  Exactly. I mean, Venus has clouds of concentrated sulfuric acid, right? So Venus is known to be extremely, extremely inhospitable. And if I recall talking to the researchers then, they were pretty skeptical about the life angle. You know, even as they said they couldn't think of any process that could make this gas on Venus. You know, it was more like, we don't really know what's up with Venus. Or like, what could there be besides life that could produce this gas? This is a mystery that we'd like to solve. This is kind of bizarre and unexpected. We don't know what to make of it. You know, it wasn't like, this is the strongest evidence for life beyond our planet.

• 11:25Regina Barber?

  Yeah, whatever happened with that, by the way?

• 11:27Speaker 02

  My understanding is that the whole thing, like, the detection and what it means, like, it's still debated.

• 11:33Regina Barber?

  Oh, wow.

• 11:33Speaker 02

  You know, I mean, you'd need a mission to Venus to settle it, which we could plausibly do. Because Venus is close by. It's literally the planet right next door.

• 11:41Regina Barber?

  But K218b, not so next door.

• 11:44Speaker 02

  Yeah. I mean, we're not going to go visit a planet beyond our solar system anytime soon. And, you know, here's the thing. There's going to be a lot more research in the years ahead, trying to tease out information about very, very faraway planets. And I think what this episode is about is scientists talking about how they can do that work and communicate it all to the public. Like, how to convey the excitement of it without overselling it or hyping it. Because there could only be one time that humans discover life beyond Earth for the very first time. And to many scientists, that's almost like a sacred thing.

• 12:20Regina Barber?

  Nell, if that does happen, we expect you to come right here and talk to us about it.

• 12:25Speaker 02

  Well, I frankly hope that I am alive. And that NPR is.

• 12:29Regina Barber?

  Yeah, me too. Thank you so much.

• 12:31Speaker 02

  Thank you.

• 12:33Regina Barber?

  This episode was produced by Burley McCoy, edited by our showrunner Rebecca Ramirez, and fact-checked by Tyler Jones and Nell. Maggie Luther was the audio engineer. Beth Donovan is our senior director, and Colin Campbell is our senior vice president of podcasting strategy. I'm Regina Barber. Thank you for listening to Short Wave from NPR.

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