Segment Transcript

IRA FLATOW: When you’re hunting for extraterrestrial intelligence, how do you even start to look? And how do you know what to look for when you have no idea what life elsewhere might look like or the technology it might use? Joining me now is Andrew Siemion, scientific director of the Breakthrough Listen project based at the University of California at Berkeley. Welcome to Science Friday.

ANDREW SIEMION: Hello, Ira. Thank you very much for having me.

IRA FLATOW: You’re quite welcome. So tell me Andrew, what exactly do you look for?

ANDREW SIEMION: Well, basically what we look for in Breakthrough Listen and really in any SETI experiment is the kind of electromagnetic emission that we know can only arise from technology. So we have lots of examples of technology here on this planet that show us what kind of emission technology can produce. And from many decades of astronomy and indeed radio astronomy, we know the kinds of emission that the natural world produces. And these kinds of emission are very different. So we look for the kind of emission that we know to only arise from technology.

IRA FLATOW: Is there a narrow band that you’re looking for? I heard in Charles’s piece that it’s the worst possible place to put your Wi-Fi. And that was the 2.4 gigahertz band. But where do you look for it?

ANDREW SIEMION: So we try to search as much of the electromagnetic spectrum as we possibly can. We have lots of different types of technology on this planet. We have radio technology like Wi-Fi routers and cell phones, but we also have optical technology like lasers that also produces emission that’s very different from the natural world. So we try to search as much of the spectrum as we possibly can with many different kinds of telescopes.

IRA FLATOW: So you’ve got four different kinds of telescopes here?

ANDREW SIEMION: Well, in the Breakthrough Listen program, we have two different types of telescopes, radio telescopes and optical telescopes. And we’re also looking at some infrared and high energy observatories as well. But basically, the idea with all of these telescopes is the same. We’re looking for this particular type of electromagnetic emission, be it radio signals, or optical signals, or other that we know only arises from technology.

IRA FLATOW: And how many people are involved in the total search?

ANDREW SIEMION: Well, worldwide, SETI probably has about 50 or 60 people that practice it at least half-time. Our team at Berkeley is made up of about a dozen people that work primarily on the Breakthrough Listen program.

IRA FLATOW: Mm-hmm. And you must produce a ton of data from all the searching.

ANDREW SIEMION: Yeah. It’s absolutely amazing. So the kinds of signals that we’re looking for with a radio telescope require us to record the most rawest possible data product that a radio telescope can produce. And the data rate that we see at the Green Bank Observatory, for example, is several gigabits per second. That’s about a petabyte of data over 24 hours.

So it’s really an absolutely massive, massive data rate. And of course, we want to search that for many different types of signals. So it’s a real computational challenge in addition to everything else.

IRA FLATOW: A petabyte is 1,000 gigabytes?

ANDREW SIEMION: A million gigabytes. That’s 1,000 terabytes. So about 1,000 modern laptop computers every 24 hours that we observe.

IRA FLATOW: You ever ask the public? Maybe they could join in, crowdsource it out there?

ANDREW SIEMION: Yeah, absolutely. So there’s a program that we operate in our group at Berkeley called SETI@home. And this is actually an application that you can download from our website. And when that application wakes up on your computer, it will download a little bit of the data from our computers at Berkeley and actually do the very computationally intensive analysis necessary to search for signals using your home computer.

IRA FLATOW: And how is all this being processed? Do you have fancy algorithms and things like that?

ANDREW SIEMION: So fundamentally, the kind of signal that we look for in SETI for the most part, be it in radio or optical, is a large amount of electromagnetic energy concentrated at just one wavelength or one electromagnetic frequency. And with radio telescopes, we look for those kinds of signals using something called a Fourier transform, which many of your listeners are probably familiar with. This is just a way of breaking down a signal that varies in time to one that varies in frequency or in wavelength.

With optical telescopes, we use basically prisms or diffraction gratings. Very, very accurate spectrographs that break optical light down into all of its constituent colors. And we look for a signal that’s only occurring at one color, which is something that, again, that we know that the natural world does not do.

IRA FLATOW: Do you have any odds of people– the bookies making any odds that you’re going to find something?

ANDREW SIEMION: Yeah. That’s a fun question. I don’t know that any of the bookies formally have odds on the SETI search. That would be fun if they did. I think when we talk about this over a couple of pints after work, the odds range from maybe a few percent to maybe a few hundredths or thousandths of a percent.

But this is, in fact, the most difficult question. We don’t know whether or not there is other life elsewhere in the universe. And we don’t know whether or not there’s other intelligent life.

IRA FLATOW: I’m Ira Flatow. This is Science Friday from PRI, Public Radio International. Talking about the Breakthrough Listen project. Dr. Andrew Siemion is the project director for Breakthrough Listen at the University of California, Berkeley.

We have a tweet from Daniel Yount who says, hey, moon base on the dark side of the moon for searching for remote signals. Put a receiver there, right? You’ll screen out all that interference.

ANDREW SIEMION: Yeah, It’s a fantastic idea. It’s actually an idea that’s been around in SETI for some time. So as we heard in that piece about the Green Bank telescope, the biggest challenge in a radio SETI experiment is telling the difference between terrestrial technology, our own communications systems, and extraterrestrial technology, something coming from a distant extrasolar planet. And a good way of getting away from our own terrestrial technology is, of course, to go to space and perhaps to build a large radio observatory on the dark side of the moon, shielded from the earth by the moon itself.

IRA FLATOW: And it would be– because it’s turning, it would actually start rotate and scan a lot of the sky.

ANDREW SIEMION: Yeah, that’s right. So we would probably steer such a telescope digitally because it would be very expensive, of course, to build a telescope on the moon. But this would be something that would be quite expensive to do. And for now, it’s only in our wildest dreams.

IRA FLATOW: Yeah. Because that would take a lot more money than you have, I’m guessing.

ANDREW SIEMION: That would be a very expensive proposition, I think, to build a base of any kind on the moon. But there’s quite a lot of interest actually in astronomy generally about having radio observatories and other kinds of astronomical observatories on the moon. So perhaps this is something that might be in humanity’s future.

IRA FLATOW: What about do you think about this? Because you’re searching because you believe that there’s got to be extraterrestrial life out there, intelligent life, or you wouldn’t be looking for it. As part of your mission, do you think about how you break the news if you actually come up with something?

ANDREW SIEMION: Yeah. That’s something that I personally don’t spend a whole lot of time thinking about. Maybe for five or 10 minutes right before I go to bed, I think about what we might do if we actually found a signal. But indeed, we believe, and most believe, that it would be among the most amazing and awe-inspiring discoveries that we could make as scientists or as human beings to discover that there is other intelligent life, other communicative life elsewhere in the universe.

And it’s very difficult to predict how the world would react to that. But I think– personally I think it would be a very positive reaction. I think it would be a very unifying moment.

IRA FLATOW: Yeah. Because it has religious, ethical, all kinds of different problems. And even there are some people who are even concerned that we let other people know that we’re here. And if you’ve got signs of intelligent life, would you then say, hey, let’s return. Let’s make a signal that we send back to say, hey, we’re here? Is that part of the idea?

ANDREW SIEMION: Yeah. That’s a very interesting question. So in the SETI enterprise, we only listen for signals. We’re simply trying to determine whether or not there is other intelligent life out there. But indeed, if we did discover a signal, many would ask the question, should we respond to it? And personally, I think that that’s a question that should involve the entire planet. The relationship between the life on Earth, human life on Earth, and life on other worlds is something that involves the entire planet. And it’s something that we should all weigh in on before we responded.

IRA FLATOW: OK. I’m going to give you the blank check question I like to give out. I don’t actually have one to give you. But if you had one, where would you spend the money? What do you need most?

ANDREW SIEMION: Well, I think, in general, the most important thing for the field of SETI is to help to develop a healthy ecosystem of researchers in the field. SETI is a field that I think has been characterized by not continuous funding, by sporadic funding. Funding that at times has involved governments and has involved private individuals. And most recently, Breakthrough Listen with the Breakthrough Prize foundation has seen a really phenomenal contribution of funding towards the field that will go for at least another 10 years or so. But I think one thing that the SETI field has faced in the past is a lack of an ecosystem of graduate students, and post-docs, and young faculty that are working in the world because of the sporadic funding.

IRA FLATOW: Well, maybe people listening here will be motivated. Andrew Siemion, scientific director of the Breakthrough Listen project based at the University of California at Berkeley. Thank you for being with us today.

Copyright © 2017 Science Friday Initiative. All rights reserved. Science Friday transcripts are produced on a tight deadline by 3Play Media. Fidelity to the original aired/published audio or video file might vary, and text might be updated or amended in the future. For the authoritative record of ScienceFriday’s programming, please visit the original aired/published recording. For terms of use and more information, visit our policies pages at http://www.sciencefriday.com/about/policies/