A Modern Way to Look for Aliens

Radio telescopes, like the Robert C. Byrd Green Bank Telescope in Green Bank, W.V., remain key components of the modern search for extraterrestrial intelligence, including in the hunt for technogisnatures. Credit: NRAO/AUI/NSF, CC BY 3.0

If you were an ant living in an anthill in the Serengeti and you wanted to know whether an intelligent species lived on planet Earth, how could you tell? A particularly clever ant might pick up a radio signal and deduce that humanity exists, but how about subtler, indirect clues that, nevertheless, are a result of technological development? This thought experiment, posed by astrophysicist Jason Wright in a recent interview, is a good introduction to the type of out-of-the-box thinking that scientists need if they’re going to join the search for extraterrestrial intelligence (SETI).

Wright, a professor at Pennsylvania State University in University Park, is a leader in the effort to reimagine SETI research and modernize it as a fully developed scientific discipline. Despite its prominent place in popular culture, SETI science has long been on the fringes of the space science community, partly because of a lack of support from funding agencies. Wright and other SETI scientists have been working to change that and give SETI all the necessary academic trappings: funding, curricula, conferences and symposia, and a canon of academic literature.

Providing opportunities and training for graduate students is a critical component of any academic discipline, and the field of SETI has begun to do just that. “You can’t have a field where everyone is a senior or emeritus professor,” said Penn State graduate student and SETI researcher Sofia Sheikh. “You need to have people at every career stage, or the field isn’t going to continue.”

In this episode of AGU’s podcast Third Pod from the Sun, Wright and Sheikh discuss what it means to search for signals of alien technology, how SETI research is modernizing for the 21st century, and how this emerging academic field is poised to be a leader in interdisciplinary research and inclusive practice.   

This episode was produced by Kimberly Cartier and mixed by Kayla Surrey.


Shane Hanlon (00:00):

Hi, Nanci.

Nanci Bompey (00:02):

Hi Shane.

Shane Hanlon (00:03):

And hi Kim, who is the producer for this episode. Hi Kim.

Kimberly Cartier (00:07):

Hi Shane, Hi Nanci.

Nanci Bompey (00:08):

Hi Kim. That’s a lot of hi’s.

Shane Hanlon (00:09):

All right. So yeah, we’ll just say Hi to everyone.

Nanci Bompey (00:12):


Shane Hanlon (00:13):

I would say hi to my dog who’s sitting outside the closet I’m in. Question for today. Does life exist on other planets? Go.

Nanci Bompey (00:24):

It has to, right? I mean…

Shane Hanlon (00:26):

Does it?

Nanci Bompey (00:27):

Doesn’t it have to? Kim… I mean, Kim’s the expert here, I feel, but…

Shane Hanlon (00:30):

Kim does have more of a background in this.

Nanci Bompey (00:32):

But she has a PhD education in some science in space.

Kimberly Cartier (00:34):

Astrophysics Nanci. Astrophysics, it has a name. I feel, like you said, it sort of has to right? We’re here. And we’re, sorry to say, nothing special, right?

Shane Hanlon (00:47):

But like aren’t…

Kimberly Cartier (00:48):

.. We’re not the center of the universe so why doesn’t life exist somewhere else?

Nanci Bompey (00:50):

I mean, given all the planets, all the stars, all the universe, all the everything.

Shane Hanlon (00:56):

Let me caveat that then. Do you think that life exists other places under conditions that are similar to the conditions that we have here? Or do we think we have to completely come up with a different way of thinking about what life is or the conditions that would be able to sustain life?

Kimberly Cartier (01:16):

Ooh. Now that’s a tough one. If you expand it to life can look like anything and exist anywhere, then how would we ever know if we found it?

Nanci Bompey (01:25):

I know. You wouldn’t even know what we’re like because you’re like that looks like a rock, but it’s really a life. This is deep. This is getting real deep.

Kimberly Cartier (01:34):

I’m pretty sure there were many Star Trek episodes like that.

Shane Hanlon (01:37):

That’s going to be a quote. I’m going to print it out and put it on my computer. “It looks like a rock, but it could be life”.

Shane Hanlon (01:43):

Welcome to the American Geophysical Union’s podcast about the scientists and the methods behind the science. These are the stories you won’t read in the manuscript or hear in a lecture. I’m Shane Hanlon.

Nanci Bompey (01:59):

and I’m Nancy Bompey.

Shane Hanlon (01:59):

And this is Third Pod from the Sun. All right. So as usual, there is a reason why I’m asking this question. And since we already brought Kim in, I’ll just go to you, Kim, what are we talking about today? Like, why are we talking about this?

Kimberly Cartier (02:18):

So we’re talking about, do aliens exist? Personally, I don’t know. We certainly haven’t found anything yet, but there are people who are trying to answer that question in a scientific way. And I talked to a couple of the people who are trying to figure it out and in the process of figuring it out, also modernize how we think about the search for extraterrestrial intelligence and transform it into a full fledged scientific field.

Jason Wright (02:46):

I’m Jason Wright. I’m a professor of astronomy and astrophysics at Pennsylvania State University. And I’m the director of the Penn State Extraterrestrial Intelligence Center. I work on problems in stellar astrophysics, exoplanetary astrophysics, and the search for extraterrestrial intelligence.

Sofia Sheik (03:03):

I’m Sofia Sheik. I am a graduate student at Penn State getting a PhD, hopefully, in astronomy and astrobiology. And I work in the area of radio astronomy. So sometimes this is on astrophysical objects like pulsars and a lot of the time it’s on the search for extraterrestrial intelligence in the radio.

Kimberly Cartier (03:26):

Right off the bat, I asked them about whether they think that what they’re searching for really exists somewhere out there.

Sofia Sheik (03:32):

I think I’m going to butcher the quote, but, “The only test of extraterrestrial intelligence is an empirical one.” Something along those lines.

Jason Wright (03:54):

That’s it. And people seem really sure that if they are out there, there’s no way they’re going to do anything that we would detect. And, you know, that’s an opinion. That’s a prior. It could be right, could be wrong, but people, some people really feel very emphatically that they are out there and we’ll find them or they are out there and we can’t find them or they aren’t out there. And you know, I’m a scientist and I like data. And so for all those people out who are saying, “There’s nothing out there to find. You’re wasting your time,” well, then I’ll put some pretty good upper limits on that.

Kimberly Cartier (04:29):

Jason, I think when most people think of the search for extraterrestrial intelligence or SETI, I think they picture Area 51 or little green men or Jodie foster with the headphones up to her ear in Contact. That’s obviously not what you do and that’s not how SETI is done, but what does SETI look like in the 21st century?

Jason Wright (04:48):

Yeah. What does SETI look like? So there’s a lot of ways that one can look for extraterrestrial intelligence. The most common is not too far from Jodie Foster with the headphones. And most of the work that’s done is in fact with radio telescopes, looking for radio transmissions.

Jason Wright (05:12):

And although it doesn’t really make much sense to put headphones on because we’re not listening in that sense that you would on an FM dial or something like that, that movie was surprisingly accurate, and really tried to get a lot of the details, right about what radio astronomy looks like. But it’s broadened today and there’s more to it than just radio astronomy. Just as old as the idea that we would find radio transmissions is the idea that we might find laser transitions that was suggested in 1964, just five years after Frank Drake started Project Osmo in the radio by the Nobel Laureate, Charlie Towns ,who invented the laser. And that looks a lot more like normal optical astronomy that people are familiar with, with optical telescopes and a camera on the back, looking for laser flashes or something like that.

Jason Wright (06:00):

But then the rest of it, we are generally looking at archival data. We’re not putting a custom instrument on a telescope and doing a brand new observation with that. We’re looking at data from the WISE space telescope and all of the archives that it produced, or we’re looking at data from the digitization of old photographic plates. And so, like a lot of science today, it’s sitting in front of a computer and writing computer programs and getting mad at those computer programs because they’re not doing what you think they should to look through huge amounts of data and look for whatever it is you’re looking for.

Nanci Bompey (06:34):

So they have all these computer programs, all this data, like what are they actually looking for in the data? Like what kind of signal would give them what they want?

Kimberly Cartier (06:44):

Jason explained to me that SETI is very similar to other branches of astrobiology in that both fields look for signs of life in the stars. Most astrobiologists look for signs of any type of life like bacteria or microbes or plants or something, using what are called biosignatures, like we look for methane on Mars or recently we found phosphine on Venus.

Nanci Bompey (07:07):

So it’s like a signature of life happening.

Kimberly Cartier (07:10):

Right, it’s a chemical signature in the spectrum of a planet’s atmosphere. But SETI scientists look for signs of advanced life like technology or communication. Communication SETI is like what’s portrayed in the movie, Contact: scientists hunting for, or stumbling upon a signal with some sort of information content. Something like a light house announcing its presence to ships or if you overhear someone’s conversation, all of those are signs of intelligent life.

Nanci Bompey (07:38):

Ah, okay. That’s the difference. That makes sense.

Shane Hanlon (07:40):

I love Contact.

Kimberly Cartier (07:42):

I do too. It’s a great movie

Nanci Bompey (07:43):

Matthew McConaughey

Kimberly Cartier (07:46):

You know, if we ever detect something like that, which we definitely haven’t, it will be really clear that what we’re seeing was actually created by intelligent life and not from some natural process.

Kimberly Cartier (08:05):

Some types of communication SETI like radio communications, for example, might also mean that there’s technology involved. That makes it also part of Jason’s domain, which is looking for technosignatures.

Jason Wright (08:18):

And this is sometimes called artifact SETI or Dysonian SETI after Freeman Dyson, where we’re just looking for evidence of technology. So you could imagine if you were a member of an anthill in the Serengeti and you want to know if there are intelligent species out there on the planet, if you could somehow build a radio receiver and pick up a radio station, then there it is. You’re done. There’s clearly a radio transmitter. But if what you’re looking for is something more subtle like the clouds behind an aircraft going overhead, well are those natural clouds or are those really the contrail is from behind a plane? Or maybe you detect the presence of CFCs or artificial chemistry in the atmosphere. And now you’re having debates: “Well, does that really mean someone out there is making CFCs or could those be natural?”

Jason Wright (09:05):

And so the nice thing about this approach is that you don’t have to assume they’re trying to get your attention. You don’t have to assume we know how they’ll try to communicate. The downside is that even when you find it, you’re not sure you’ve found life. And so, one side I think is more likely to succeed because it looks for a broader class of signal, but the other, the communication SETI, is more valuable because that’s the only way you’ll really know you found it.

Kimberly Cartier (09:30):

Because otherwise there might be some sort of false positive. There might be some sort of non-biotic way for that signal to come about that we just may not know about yet?

Jason Wright (09:40):

Right. It’s very similar to the search for biosignatures in the rest of astrobiology, that if you see methane on Mars, that would be really interesting and that’s the sort of thing life would do. On the other hand, you can imagine all of these other processes that might produce methane abiotically. And so you’re not necessarily sure you’ve found it. And then I suppose to complete the analogy, if you actually found the mold growing on the rock on the ground, that would just clinch it. And now you’re sure that you found life.

Shane Hanlon (10:13):

I have to sidebar here. In between recording this, Kim and I didn’t know if Matthew McConaughey was in fact in Contact. So we had to do some quick Googling and kudos to you, Nancy. It turns out he is. And if you actually look at, I just looked this up, his picture, it’s him and Jodie Foster, but he’s on the picture of Contact. And I had no idea.

Nanci Bompey (10:36):

Thank you.

Shane Hanlon (10:41):

But getting back to the episode. There are so many different ways of looking for alien life and I feel like this is such a popular thing, at least in our popular culture and kind of like in the non-science public. It seems strange to me that SETI has kind of stayed on the fringes of science or at least not taken as seriously as I might expect.

Kimberly Cartier (11:03):

You’re absolutely right Shane, I mean, SETI has been around for decades, going back way earlier than people like Freeman Dyson and Carl Sagan and Jill Tarter, who, point in fact is a real life scientist that Jodie Foster portrayed in the movie Contact.

Nanci Bompey (11:18):


Kimberly Cartier (11:19):

But for a long time SETI wasn’t actually supported by science as a scientific field by NASA or other funding agencies because of congressional pushback. It’s politics. So only a handful of people in the US have been working on SETI during the eighties and the nineties and the early two thousands, and only at a few private research centers like the SETI Institute in California. But that has been changing recently, for example, with the establishment of the Penn State Extraterrestrial Intelligence Center. And there was recently a NASA sponsored workshop on technosignatures.

Jason Wright (11:54):

There’s even been a recent success actually at the University of Rochester. Adam Frank has had the first successful NASA SETI proposal to do research. Not just build hardware, but do research in SETI, since forever. So the idea is, we’re looking at these planets around other stars, we’re looking for biosignatures. And the way you do that on a planet around another star is you look at the light that filters through the atmosphere when a planet passes between the star and the Earth. And you look for signatures of metabolism, like for instance, you might look for the simultaneous presence of ozone and methane because on Earth, those only co-exist in the atmosphere because we have both plants and animals doing metabolism and all of that. So that would be a bio-signature.

Kimberly Cartier (12:38):

Upcoming telescopes like NASA’s James Webb and Europe’s ARIEL telescopes will be looking for those kinds of biosignatures in the atmospheres of extra solar planets.

Jason Wright (12:47):

But what if we look at one of these spectrum, of these exoplanets and there’s something we don’t recognize at all? It’s not carbon, it’s not oxygen. What if it’s like a chlorofluorocarbon? The chlorofluorocarbons we’ve already put in our atmosphere are actually almost detectable. They’re not quite, you need about 10 times as much, but you could imagine on another planet they might be. So what would artificial atmospheric technosignatures even look like? No, one’s really worked it out before. It’s an idea, but it’s not something you could look for yet.

Kimberly Cartier (13:26):

As this sort of new era of SETI research is gaining speed, what role do you see the PSETI center playing?

Jason Wright (13:34):

The point behind the PSETI Center was to create that academic home where you do the things that academics do, which is turn a practice into a discipline and create a curriculum and create a canon and create textbooks and advance the field so that people stop re-inventing the same ideas over and over again, or writing papers without reading all the previous ones and citing them, which is basically what’s been going on.

Kimberly Cartier (14:00):

And part of what academics do is train graduate students like Sofia.

Sofia Sheik (14:04):

If you asked me 10 years ago, what I thought I would be doing the answer would not be looking for aliens. So I was looking for a new research mentor and I was browsing through Reddit of all places. And on the front page of Reddit, there was a story about a hundred million dollars being given to the search for extraterrestrial intelligence. And I saw the name of the PI and I didn’t recognize the name, but it said he was at UC Berkeley.

Shane Hanlon (14:33):

I love that she joined the field because she found it on Reddit. Like I work in social media, in science communication on social media. I tell people all the time, yes, it can be a dumpster fire, but there’s some real good stuff out there. And this is a case, I guess, for my argument.

Kimberly Cartier (14:52):

Yeah it’s definitely my favorite career origin story that I’ve ever heard. So, after she found this scientific project on Reddit, Sofia’s mentor, put her in contact with the PI on the project, and that got the ball rolling to where she is today at Penn State. So in addition to doing SETI research, Sofia took a graduate course in SETI that was designed and led by Jason, and they explored the decades of academic literature on the topic, they discussed and debated the different approaches to the research, and they even designed and executed a real research project where they traveled down to the Green Bank Radio Telescope in West Virginia.

Sofia Sheik (15:36):

When we started the project at the beginning of the course, about half of the students taking the class decided that that was what they wanted to focus on. So we started with the constraint of, we get the hundred meter Green Bank Telescope for about six hours. What are we going to do with it that is related to SETI? So it was very open-ended to start. And I was not part of the group who designed the observing plan. So I will give credit where it’s due. There were other students who came up with this idea. But in the end, the idea was to look at about a dozen stars with known planets around them and specifically, planets that transited their stars as viewed from Earth. So we knew they were there because we’ve seen the planets transit before. And we wanted to look for radio signals coming from those planets at the time when they were in transit. So this is kind of a special time or a special geometry because the Earth and the planet and the planet’s star are all aligned. So the idea is that maybe that’s a better than average time, if you’re going to send a signal, it might be a good idea to pick a time that everyone could figure out. So that was kind of the philosophy behind the search.

Sofia Sheik (16:55):

And that idea of trying to find a special time that might be more likely is actually an idea in game theory called a Schelling point. SETI is very interdisciplinary and people had talked about this and given it a bunch of different names in the study literature, but it turns out they’d been talking about it in a different field for decades. So, oops. But, kind of one everyday example of a Schelling point is if you were going to meet up with your friend, but you forgot to specify what time you were meeting up, maybe you would say, “Well, we’re probably going to meet up on the hour” or “We’re probably going to meet up at noon.” It would be weird for your friend to be like, “Wow, I expected you to meet me at 9:53 and you didn’t meet me.” There are certain times that are more important or more obvious. And so we’re basically applying that same logic to times that are more important or more obvious for signal sending in an astrobiological sense.

Kimberly Cartier (17:54):

So aside from looking for radio signals from exoplanets and wandering interstellar objects like ‘Oumuamua, or looking for heat given off by Dyson Spheres, what other ideas are studying scientists hoping to explore in the future?

Jason Wright (18:07):

I don’t know, sometimes I like to say that the technosignature we’ll find first is probably going to turn out to be one that we haven’t even thought of yet. And we might stumble across it by accident so we need to keep an open mind. So, I think we’re still at the just try everything, grow the field, brainstorm part of this very young field, while keeping in mind that we do have some mature search strategies that we haven’t really tried very hard at yet. And that’s one of the great things about Breakthrough Listen’s radio program, is that we’re finally really trying that project in radio SETI that Jodie Foster tried in Contact, but really hasn’t been tried very much.

Sofia Sheik (18:46):

I also have been thinking about gravitational wave SETI a bit recently. Specifically, if you have a very large linearly accelerating mass, aka, a spaceship, what kind of gravitational wave signature would that leave? Is it something that we could detect with either current instruments or upcoming instruments? So, that’s been an adventure of a project. And I think something that I want to move into that I don’t actually have on my plate right now, is thinking more about anomaly detection in large data sets. Big data is kind of our buzzword right now in astronomy, as in every field I guess right now. But especially with really large upcoming survey missions and even current missions like TESS where you’re getting a ton of data coming in that are not explicitly or even implicitly, most people would not think about them for the purposes of SETI—But if we were to find something that we couldn’t explain by known astrophysical phenomena in that data set, that would be interesting. It doesn’t necessarily have to be aliens, right? In fact, “it’s never aliens” is a common tweet that I stand by, but we can find really interesting things about the universe by finding the things that don’t fit our current understanding. And so developing methods to go through these large data sets and pull out things that don’t look like everything else is valuable in general for astrophysics and it’s valuable for SETI. And I think that’s a really rich area that’s going to require a lot of interdisciplinarity between astronomers and data scientists.

Sofia Sheik (20:33):

But, you can’t have a field where everyone is a senior or emeritus professor. You need to have people every career stage or the field isn’t going to continue. You need to have these ideas continue to trickle down to people who are moving into the field, but are also moving between different fields interdisciplinarily, or who are fluent and say data science and computation.

Kimberly Cartier (21:10):

The fact that SETI, as a modernized rigorous academic discipline is so young means that it’s less beholden to some of the outdated views and harmful power structures that are entrenched in other scientific fields.

Shane Hanlon (21:21):

Yeah. I mean, I really love this. And especially right now, when so many scientific fields and institutions are trying to figure out how to either change or reform themselves to be more inclusive and to reach out for example, to the computer sciences or the social sciences and to be interdisciplinary and bring more folks from not only different fields, from different backgrounds and different socioeconomic backgrounds. It’s, really great to see a discipline that basically is doing this from the beginning rather than having to go back and kind of fix the way they started.

Jason Wright (21:54):

I like that perspective that it’s a young field, which means we get to decide what it’s going to look like in every way, and that includes who practices it and how we interact with each other, in addition to which parts of it we pursue.

Sofia Sheik (22:27):

Something that I really enjoy about SETI is the way that it forces me to think outside the box and also outside of my brain as a human, as much as I possibly can, being a human. So because of that, it kind of exists in this unique position where we can’t just look at the data and be like, ah, yes, this is clearly a signal from extraterrestrial intelligence because this is clearly what they would do. Because we’re imposing human bias on that, just by being human. So what we really need is expertise on how humans think, what we do, what human cultures have done and do. And so it’s really useful to have input from people who work in the humanities, in sociology and anthropology. And some of my favorite discussions I’ve had about SETI have been with colleagues in those fields. And I think that’s something that is easy to forget or overlook when we work in astronomy and we’re in our little siloed departments. But it kind of reveals how much astronomy needs the input from not just astronomers and physicists, but also ethicists and sociologists and anthropologists. And those kinds of collaborations can bring really rich and interesting discoveries and also self-reflections.

Sofia Sheik (24:03):

And so that’s one aspect of the field that I think doesn’t get highlighted enough, in the purely scientific discussions. And kind of along those lines, I think SETI is in a very unique position in that it’s such a young field and is in kind of this interesting transition, perhaps Renaissance, period, where now we’re aware of a lot of the institutional problems with astronomy. We’re aware of the history and how that has affected disproportionately, people from underrepresented groups. And I think SETI’s in a unique position to take that knowledge and kind of make it right, to be a subfield that’s on the forefront of making sure we’re inclusive, making sure we’re diverse, making sure that we’re incorporating perspectives from people in all walks of life and people from across the world. Because if we’re trying to step out of our brains as humans, but everyone involved in the conversation speaks English or everyone involved in the conversation is of European descent, then we’re not really getting the human experience, are we? So I think it is very important for SETI to be on the forefront of diversity and inclusion. And I think we kind of have a unique position to make that happen.

Kimberly Cartier (25:25):

That’s so well said. And you know, I think that this is a lesson that applies not only to SETI as it’s building its practice and its discipline, but also that applies to so many other scientific fields and really all of science as we’re looking towards what’s to come.

Nanci Bompey (25:55):

Yeah. So true. I mean, if we’re to tackle these big challenges we need to be as diverse and inclusive as possible.

Shane Hanlon (26:02):

Yeah, totally agree. All right, folks. Well, that is all from Third Pod From The Sun.

Nanci Bompey (26:08):

Thanks so much to Kim for bringing us this story and to Jason and Sofia for sharing their work with us.

Shane Hanlon (26:14):

This podcast was produced by Kim and mixed by Kayla Surrey.

Nanci Bompey (26:18):

We would love to hear your thoughts, please rate and review us on Apple podcasts. And you can find new podcast episodes wherever you get your podcasts or always at thirdpodfromthesun.com.

Shane Hanlon (26:30):

Thanks all. And we’ll see you next time.

Shane Hanlon (26:40):

Do y’all remember, what was it, a screensaver? The SETI screensaver?

Nanci Bompey (26:45):


Kimberly Cartier (26:47):

It’s called SETI @ Home.

Shane Hanlon (26:48):

SETI @ Home. What were they? And it was essentially like sharing processing power. Right?

Kimberly Cartier (26:54):

Right. There’s just like troves and troves of data that there just aren’t enough scientists in the world to go through or computer power at any one research institute. And so if you installed this screensaver, it would sort of hijack a tiny portion of your computer processor to help go through the data. It was so cool.

Nanci Bompey (27:13):

I feel like that was a really big thing for awhile. Like if you had that…

Kimberly Cartier (27:16):

It was.

Nanci Bompey (27:17):

…you were pretty cool.

Shane Hanlon (27:18):

Why don’t…

Kimberly Cartier (27:19):

I felt cool having it, but I don’t know if other people thought it was cool.

Shane Hanlon (27:23):

Why don’t they have screensavers anymore?

Nanci Bompey (27:25):

I know we were just, I know it’s like we just, we don’t save our screens. We just are in our screen.

Kimberly Cartier (27:30):

We’re always at our computers. So the screen never goes dark.

Shane Hanlon (27:34):

We’re going to start a campaign to bring back screensavers.


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