Short Wave - Did E.T. Phone Us?

Episode Date: January 27, 2022

A few years back, a radio telescope in Australia picked up a radio signal that seemed to be coming from a nearby star. One possibility? Aliens! NPR science correspondent, Geoff Brumfiel, joins the show to talk about the signal and how a hunt for extra-terrestrial life unfolded.Check out the work from Sofia Sheikh and her team at the Berkeley SETI Research Institute about what they learned from the signal: https://bit.ly/3rM6hCoYou can email the show at [e-mail]. 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. Emily Kwong, have I got a question for you? You always do, Jeff Brumfield. What is your question? Have you ever thought about how aliens might phone us and then like how we might be able to pick up that call? I think since the days of E.T. Yeah. I pretty much went through a stint where I only ate Reese's pieces and the hope that something would happen.

E.T. was just so cute. Well, it turns out there's a very small group of scientists who have dedicated their entire careers to thinking about this specific problem. And one of them is Sophia Shake. She sums up the challenge this way. How in the world can we use our technology on this pale blue dot to detect someone else's technology? I didn't realize there were scientists that did this. Yeah, yeah. You know, a lot of times it's just a thought experiment.

but a couple of years ago, Shakes Group picked something up, a signal that seemed like it bore a lot of the telltale signs of a real-life alien radio transmission. I have a notion of what this means from sci-fi movies, but what does that mean

in the world of real-life research? Honestly, it looks like some of those sci-fi movies. It means that there was like a big radio dish, pointed at the sky, and it picked up a signal that sounded like it came from another civilization in another star system. Do you want to hear it? Heck, yes, I do.

That's creepy. That is creepy. That's creepy. That makes me uncomfortable. That makes me think these aliens are going to be the like, I'm going to eat you type and not I'm going to like, the friend you type. Yeah. It filled you with dread, but it turned out it really excited Sophia and her team because this was the first time they'd seen a candidate that could be alien in origin. I really wasn't sure. With the information we had, it was consistent with an extraterrestrial signal, but it also could be consistent with other things.

So today on the show, we'll hear the story of this real-life search for ET. And what has taught scientists about how to look for more signals in the future? You're listening to Shortwave, the Daily Science Nerdcast from NPR. Okay, Jeff, so we are going to talk about a real-life signal that's, Scientists thought might be from aliens? I cannot believe. Where do we start? Like, first of all, who picked up the signal and where? Right, right, right. So this signal actually showed up in 2019 in Australia. There's this big radio telescope near Sydney called the Parks Observatory. And it detects the signal while it was looking at a star called Proxima Centauri. And that's really, really exciting because Proxima Centauri is. actually the closest star to the sun. It's just a little over four light years away, which is like nothing in intergalactic speak. Like if there were aliens living on Proxima, they definitely want to like pop over and pay us a visit.

So this is really sci-fi movie stuff in the making. But the signal doesn't get noticed right away. Why is that? Well, to understand, why not? The first thing you got to know is how this whole thing works. And when I say this whole thing, I'm talking about the search for. extraterrestrial intelligence, which is often called SETI. And the thing about SETI is, it's considered a pretty big long shot. The fact is there are billions of stars and galaxies out there.

So the chances of actually listening to the right one with the aliens tends to be really teeny. In fact, NASA stopped funding SETI in 1993. And since then, it's mostly been privately funded through nonprofits. And the astronomers involved, what they sometimes do is they piggyback off other observations. So in this case, the Parks Telescope was watching Proxima for stellar flares. That's just kind of part of the practice of good science and also shows that, you know, while you're doing this sort of very niche almost SETI research, you can also be progressing other avenues of science at the same time. So they collect their stellar flare data, but then they also send it over to a team of SETI,

scientists who can look at it, you know, whenever they get around to it. This is like contact in real life. It is. It is. Like the Parks Telescope looks like those giant radio dishes for those of you've seen contact. And who was like the Jody Foster of this project? Who found the potential signal? It was this guy. I am Shane Smith and I am a senior undergraduate studying physics at Hillsdale College.

An undergrad. I love it. All right. Yeah, yeah, Shane was a summer intern with the Berkeley SETI Research Center, except in the summer of 2020, like the rest of us. He was in lockdown. He couldn't go to Berkeley. He was in Hillsdale, Michigan. I was in the basement of my house on my computer eight hours a day looking at data. I was listening to music. It's a lot of Wolfpack, actually. Well, he looked at 8,000 of the most promising signals. You look by hand through those 8,000, we call them events. So most of this stuff turns out to be nothing. Okay, that's not interesting.

Until he found a signal that looked real. It passed all of our filters. Okay. Well, tell me about these filters. How did Shane know that something in space could be an alien signal? So at the time, there were three things that researchers were looking for. So number one, the signal had to look like it was coming from a point in the sky. And in this regard, it definitely fit the bill.

It was only appearing when the telescope was pointed toward proxumus natari. Second, it was narrow band. And that's just a fancy way of saying that it was in a narrow frequency range, kind of like a radio station on Earth. And third, it was changing in frequency over the course of the observation. Changing in frequency. What does that mean? Okay, so on Earth, like a radio station, we'll just broadcast at one frequency, say 90.3 WPLN. You often hear it during the callouts. But when a signal comes from another star or planet, the frequency will change as the Earth rotates. This is called the Doppler effect.

Like a police car coming towards you with a siren. The pitch of the siren is going to be shifted. Oh, yeah. I remember learning about this in high school physics. So in this case, because the Earth is moving. the frequency is shifting, and it kind of resembles the Doppler effect. Exactly, exactly. So to sum up, it seemed to be coming from the direction of the star. It was a very narrow frequency like a radio station, but shifting over time like it came from deep space. That sounds very promising.

Oh, it does, but it turns out there's a little bit of a caveat here. Our modern world is just full of radio transmitters. Oh, so there's a lot of noise kind of. coming from other radio transmitters that could be mixed in with this potential signal. Yep. I mean, anything you can think of these days probably broadcast a radio signal. Navigational beacons, television, Wi-Fi, Bluetooth headphones, even. They all send out radio waves.

So the team had to get to work trying to eliminate all the possibilities on Earth. You know, planes crossing overhead, satellites orbiting the Earth, you know, cars, passing by on a nearby interstate. And the signal wasn't coming from any of those sources, but then as they looked more closely at it, it also kind of didn't match like it was coming from Proxima Centauri. There were some features of the signal that just didn't really make sense. So Shake decided to look at it a different way.

So she went back to the original data that came from the telescope, and she really took a broader search. She went back through everything to see if there was, some other place where this signal was showing up or some other thing that could explain it. Did we see it in any previous observations with this telescope, like anywhere in the sky? Do we see it like the days before and after the detection? And so when they tried this approach, they actually found a lot of signals that looked identical to this one.

Oh, like copycat signals? Exactly. And once you see these copycats, then it's clear this isn't really an alien signal. I'm sorry to say. This is coming from somewhere on Earth. All of these were fading in and out at different times, and one of them happened to match where it faded in when we looked towards Prexma Centauri and would fade out

when we turn the telescope another way. Okay, so in other words, they just happened to hear this funny signal when the telescope was pointed at the star, but there were actually a lot of other signals just like this one coming from other directions, meaning it's not coming from the star, really. Yeah, that's exactly right.

this turns out to be a fairly common problem that can happen with modern electronics. Maybe a wire comes loose. And a transmitter will send out dozens of copies at different times and frequencies. And so one of these copycats just happened to appear when the telescope was pointed at Proxima. Okay. And we weren't being hailed by aliens on Proxima who wanted to like stop by. Nope, nope. Okay, so I mean this with nothing but kindness in my heart.

and I was an undergraduate too, but how did Shane miss all of these copycat signals? All right, look, look. This wasn't Shane's fault. He was seen like this tiny slice of the picture because it turns out the telescope actually collected four million signals. And so a computer was used to filter out most of them automatically.

The 8,000 Shane had to review were just a small part of all those Bluetooth headphones and Wi-Fi routers sending out stuff. Basically, I just wasn't seeing everything. I wasn't seeing the whole story, I guess. Yeah, no aliens sliding into the DMs. Oh, well. Yeah, welcome to the life of a setty researcher. This is how it often goes.

In fact, it's how it's always gone, until now, at least. I have newfound respect, though, for their tenacity in this quest. What did they learn from all of this? Because no science is meaningless, right? It adds to our understanding of the universe. Absolutely. And in this case, I mean, they learned quite a lot. So first of all, remember, the telescope was looking at flares, and they got some pretty cool data on that.

But for Sophia and her folks, the first thing they learned was that there aren't obvious signals coming from Proxima Centaurian. Believe it or not, that counts. That's information. That tells us where the aliens are not, if you would like to put it that way. But it also helped the team develop better methods for screening out all the noise. They actually managed to publish two papers in a journal called Nature Astronomy about the signal. and the lessons had taught them. So they'll be able to search for signals in an even more precise way than they could before.

That's exactly right. They've created a whole new system for checking and verifying signals based on what they've learned. And, you know, if you're a scientist hunting for ET, this is just the way it goes. Sophia has a really good attitude about it. Even though this particular signal turned out to be human in origin, the next one might not be. Or it might be. And you just kind of have to keep bugging along. Jeff, thank you for bringing us this story.

Seriously, let us know if they ever do find aliens. Of course. Although I bet you'll be way too busy to talk to us at that point. Oh, no, of course, Emily. You'll be the first to know. Don't worry about it. Yeah, I better be. This episode was produced by Eva Tesfi and edited by Omina Khan.

Regina G. Barber is our scientist in residence and helped us with this episode. Regina, welcome to the team, and Catherine Seifer checked the facts. The audio engineer for this episode was Gilly Moon. I'm Emily Kwong. And I'm Jeff Brumfield. Thanks for listening to Shortwave.