Short Wave - The serious hunt for alien life

Episode Date: February 23, 2026

Bring up aliens and a lot of people will scoff. But not everyone is laughing. Around the turn of the century, 3.8 million people banded together in a real-time search for aliens — with screensavers. It was a big moment in a century-long concerted search for extraterrestrial intelligence. So far, alien life hasn't been found. But for scientists like astronomer James Davenport, that doesn't mean the hunt is worthless. It doesn't mean we should give up. No, according to Davenport, the search is only getting more exciting as new technology opens up a whole new landscape of possibilities. So, today, we're revisiting our episode on the evolving hunt for alien life. Want more space content? Let your opinion be heard by dropping us a line at [e-mail]! 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.See 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

You're listening to Shortwave from NPR. When I was a teenager in the late 90s, I downloaded a special screensaver. It had lots of pretty colors and graphs, but that's not why I wanted it. My goal was to humbly contribute to humankind's search for intelligent life in the universe, aka aliens. This effort is officially called the Search for Extraterrestrial Intelligence, or SETI. The screensaver I downloaded called. SETI at Home, was part of a large-scale community project to use people's everyday PCs to comb through radio signals that hit Earth from space, mostly from stars. These signals have particular patterns.

So if astronomers find a signal that doesn't quite fit those patterns, it could mean some intelligent life is sending them. Within a few years, the SETI at Home project recruited 3.8 million people. I hijacked my parents' little Gateway 2000, and I absolutely cooked it trying to contribute to what seemed like the thing, right? It seemed like the one opportunity living in the middle of nowhere and sort of like rural eastern Washington, like, oh, I can be part of this journey that humankind is on. It was amazing. That's my friend James Davenport. He's an astronomer at the University of Washington, and his focus is on stars. And I talked to him recently because, importantly, for this episode, he's a collaborator with the SETI Institute, a nonprofit research organization.

that combs through astronomical data in search of signs of life outside of Earth. It's a search that goes way back, way before James and I took control of our family's computers, in 1924. When many researchers were excited about Mars, and Mars's orbit was close to Earth, making it a prime time to listen to signals from the planet.

And so, an unconventional astronomer named David Todd convinced multiple radio stations in the U.S. and one in South America to go silent. So for five minutes, on the hour, for several days, they would black out all radio transmissions in the U.S. And they would listen. They would point the radio telescopes or the radio transmitters they had at Mars. And they would listen for signs of, you know, Martian NPR. David Todd even convinced the U.S. Army and Navy to listen for anything unusual in radio signals. Spoiler, they didn't find anything. There was no Martian NPR.

But humans have continued to look for signs of intelligent life in the universe. And James says we've barely scratched the surface. If the thing we were looking for was the size of the ocean, so far as of about 2000, we had looked at a pint glass of water compared to the volume of the ocean. And that's where our scientific efforts have mostly been, looking at radio transmissions from outer space. SETI has looked for spikes, chirps, and unusual things from radio telescopes for about 60 years. But James and others think there's so much more data to sift through outside of these radio signals. So today on the show, a legitimate look at the search for intelligent life in space.

The ways we look and how scientists are taking the search to the next level. I'm Regina Barber and you're listening to Shortwave, the science podcast from NPR. Okay, James, let's just like get into it. There's this equation that people throw around. It's an equation that tells us the likelihood that there's alien life that could send us a signal. It's called the Drake equation. Can you break that down for us? So the Drake equation is the number of stars times the fraction of those stars that should have intelligent life.

It's capable of sending us signals. In the simplest form, it's the number of stars times the fraction of stars that have NPR. Or something like that. Now, what goes into that NPR term? Well, you have to have a planet. It has to be at that Goldilocks distance from its parent star. It has to have water. It has to have all the ingredients that we know.

and many of the ingredients we don't know. And there's a lot we don't know about what drives life. So the last 25 years, there has been a really big surge in this field called astrobiology. And they've tried to answer the parts of that equation, like, well, how many stars have planets? Is it every star? Is it only stars like our sun? So now we know that on average, every star roughly has at least one planet. Wow.

At least one rocky-type planet on average. Wow. That means. So many. That means there's so many. That means that for a galaxy of more than 100 billion stars, that means we have at least 100 billion planets to search. And even still, even after 25 years of astrobiology, we still don't know. There's still enough unknowns in that equation that we don't know the answer still.

So there's a lot of work to be done. And the Drake equation doesn't take into account time. I personally was like, okay, the universe is like 13.8 billion years old. our sun is like around 4.6 billion years old. I feel like there could have been civilizations that were come and gone by that point. But that equation doesn't take that into account. You can write it in a way that does, right? You can write it in such a way that how many civilizations arise and what's the likelihood that they live long enough to develop radio telescopes and astronomy and space travel perhaps.

So you can write the equation sort of in different ways. It's not a strict equation in the same way as Einstein's theory of relativity. It's an equation that gives us kind of an outline for how to frame the problem. It's more of an illustration. Okay. So this illustration, this equation comes from a man who kind of began what led to like modern SETI. So really what we consider the beginning of modern SETI is 1960. So Frank Drake, who some people know from the Drake equation,

which tries to quantify what's the likelihood that we're alone in the universe. He was actually the pioneer where he had time on a radio telescope for good bread and butter astronomy reasons. At this point in the 1960s, people are looking at galaxies and gas and dust in the sort of interstellar medium. And radio telescopes are a new technology still. And he decides to point it at a couple of nearby stars to quote unquote listen. With the intent of looking for, again, chirps or pulses or some kind of transmission, he doesn't find anything. But he starts what he calls Project Ozma, named after the Wizard of Oz. Oh, my gosh.

Right. Okay. Cool. And he starts to look for signs of, you know, transmissions, intentional transmissions from technology. And this is really the beginning of what we call SETI, the search for extraterrestrial intelligence. Okay. And since SETI has like been efficiently operational, that's like 1985, we haven't found anything, right? But you mentioned that analogy that like we've only searched like the equivalent of a pine glass of water versus like the ocean that is the entire sky. We've done a lot of work since.

So my estimate a couple of years ago was we've pushed that from a pint glass of water to maybe a hot tub. Okay. That's not bad. Yeah. That's massive progress, right? There's a lot of pint glasses in a hot tub. Yeah. Yeah.

But you're an astronomer, right, that looks at stars, not radio signals. But you're working with studies. So, like, how are we going to search more of the sky? Like, get more than a hot tub in an ocean of water. Right. So I am an optical astronomer. By training, I'm a stellar astronomer. I look at stars.

with sort of classical optical telescopes that you would look through with your eyes and we attach digital cameras to. This is not the area that SETI has worked on for like 60 years, but we have put a lot effort into it for lots of other astrophysics and astronomy reasons because stars are bright and there's fun physics. There's lots to learn there in the cosmos. And that's what I spent 20 years doing. And then this realization that we're putting all this money into optical astronomy, why aren't we looking for maybe the most interesting thing, looking for life, looking to answer these questions, about whether or not we're alone. My inner eight-year-old, my inner Star Trek nerd, started putting this together that we should

use the data that we have and try to figure out how to pull the knowledge from 60 years of radio astronomy and apply it into this optical, visible light astronomy. My hope in pushing this from the radio into the visible light, into the infrared and other domains of astronomy that are so active is that we can actually push this from a hot tub to maybe an Olympic swimming pool. Okay, so there's even better technology on the horizon to make the search even more comprehensive. I'm thinking of like the massive Vera Rubin telescope being built in Chile right now. How do you see this telescope impacting like how we look for life outside of Earth?

So just yesterday, the very first like... Yesterday being January 14th. Right. The very first like commissioning image from the telescope from like their engineering camera was shown. Wow. And it's beautiful. and it's early days, but like the telescope is now being tested and everything is being aligned. So it has gone from 20 years of development to a reality.

This telescope, it's going to sit in Chile and for 10 years create this mosaic movie of the sky. And it's going to watch the sky every night with the world's largest digital camera built in California, shipped all the way to Chile. This camera is the size of a small car. It's massive, powerful camera. attached to an 8.5 meter telescope, right? So an enormous piece of glass, one of the sort of ten biggest pieces of glass ever built. It's incredibly powerful. And what you get for all that is a sample of more than 10 billion stars.

The best samples of stars so far are 1 to 2 billion. We're going to push that up to 10, maybe 15 or 20 billion stars in our galaxy. Wow. That's a total transformational shift. It's going to be something that really is a tide that raises all the stars. sort of astronomical boats. We're going to see the binary stars and the supernova. We're going to double the known number of asteroids and comets in the solar system in the first year.

You're getting me excited. Good. But James, all these decades of searching, we really haven't found anything. How are you this patient? Like, how do you keep yourself inspired that, like, this is going to be like this new era of SETI? Because success doesn't depend on finding something, right? The search itself is like the journey is the thing that we're after. Wow.

It may take, and this is what I tell my students, it may take a thousand years to know the answer to this question. We've only just begun looking. 1960 was not that long ago. Right. And even if we do all of our work and we get it up to a swing pool as compared to the ocean, that's only one swimming pool against a very big ocean of possible parameter space that we're looking. It is going to take a long time to put this story. together and to be sure that we have found something or that we haven't, that we're alone or that

we're not, that's okay. The advent of photography and computers means that our data is forever. So a star that doesn't do anything that seemed boring to us for 10 years, 25 years from now, it might do something interesting. And if we don't have that record, if we don't do our work, then they don't stand a chance of finding anything. James, thank you so much for coming here and really making me excited. about searching for life in space. If we all pitch in, if we all do a little bit, like we did. Like we did with those screensavers.

With the screensabers when we were kids. If our entire community of astronomers and scientists and the public come along with us, we're going to make a temp. This episode was produced by Burley McCoy and edited by a showrunner of Becca Ramirez. Tyler Jones checked the facts. Kwayze Lee 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 Shortwave. From regular old NPR, not Martian NPR.