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Jill Tarter is Director of the Center for SETI Research at the SETI Institute in Mountain View, California. She served as Project Scientist for NASA’s SETI program, the High Resolution[…]

A conversation with the Director of the Center for SETI Research.

Question: How did you get interested in the question of life on other planets?

Jill Tarter: I was a graduate student for many, many, many years and as I was about to go off and do a post-doctoral fellowship... an astronomer at Berkeley had a great idea. He had been taking note of the work that had been going on at NASA Ames and their interest in searching for extraterrestrial intelligence, and the early papers that suggested that radio telescopes were good tools and he said, "Oh gee, UC Berkeley has a radio telescope." And he understood enough physics to know that it's possible to take some of the signal from a radio telescope and amplify it and do different things with it and you don’t hurt the primary observer. So he thought, well we can just steal a little of the signal and we can look for engineered signals rather than astrophysical signals. It was a really clever idea of a way to get a lot of telescope time inexpensively. But of course, he had no money and so he went scrounging and somebody gave him this old computer and he said, “Well what do I do with that?” And they said, “Well you know Jill used to work on that and she is still around. Maybe she can help you.” 

So he came to my office and he gave me something called the “Cyclops Report." That was an engineering study done at Stanford and NASA Ames and it talked about how you could use radio telescopes to search for extraterrestrial intelligence and what I got out of that was this "aha" moment. I said, you know, for thousands and thousands of years people have been asking the priests, the philosophers, whoever they thought was wise, what we should believe about whether there is life elsewhere. And now, in the middle of the 20th century suddenly we had some tools and we could do an experiment to try and answer the question. And I thought "Oh wow, I’m alive at just this moment in history. I have this opportunity to try and answer a question that people have asked forever and how could you not?" So yes, I remembered how to program that computer and I began working with this group and I got hooked and I’m still hooked. 

Question: Did you wonder about extraterrestrial beings as a child?

Jill Tarter: Well when I was growing up television was very, very new and there used to be these Saturday morning cartoon shows for kids. There was also "Flash Gordon," and I watched Flash Gordon zipping through space with these ray guns and things and I thought that was spectacular. And I suspect that had a lot to do with just setting up a worldview for me so that later when I walked on the beach with my father and... it was dark, it was the Florida Keys, the sky was very dark and my father taught me about the constellations and I looked up. I don’t think there was ever a time when I didn’t just assume that those stars up there were someone else's suns, and that on some other beach, on some other planet there would be a small creature walking along with their parent and gazing at our sun in their night sky, and wondering whether we were here just as I was assuming that they were there. So, from an early time I had always thought about the fact that it would be possible to have life on planets around other stars. 

Question: Do you think we will discover extraterrestrial life in the next 50 years?

Jill Tarter: Detection of an extraterrestrial signal indicating someone else could happen tomorrow; it could happen never. I mean we actually don’t know the answer to the question of whether we’re alone. We could be the only intelligent species in our galaxy, if not the universe. That is the question we’re trying to answer. Certainly the exponential increase in our technical capabilities is breathtaking. To try and predict what it is going to be 50 years from now is pretty darn near impossible. In fact, there are probably technologies that we haven’t yet invented, which actually might make a lot of sense for interstellar communication. So I guess the best plan there is to stick around long enough so that we get smart enough to invent that and then start using it in our SETI searches, along with keeping the radio and the optical going because they’re not bad ideas either.
: How has the search for intelligent life evolved over the past 25 years? 

Jill Tarter: It’s really all about computing. It’s all about speed. How much of this really vast universe, how many of the 400 billion stars in our Milky Way galaxy can we explore, looking for someone else’s technology? And today the tools I use are 14 orders of magnitude, 14 factors of 10 better than Frank Drake was able to use in 1960 and that improvement is going to continue, and continue at a faster and faster pace, because our computing capabilities are improving exponentially. For anyone who has ever studied an exponent, things double and then they double again and that doesn’t seem very much, but after you get through a number of doublings in fact you’re making changes at an enormous rate, so everything kind of happens at the end. We’ve recently built a brand new telescope to do SETI and radio astronomy all the time and simultaneously, and with that telescope in the next 10 years we expect to be able to observe at least a million stars, maybe 10 million stars over a wider range of frequencies simply because the compute power is there and it is getting better every day. 

Question: What signal is the radio telescope looking for? 

Jill Tarter: Well what we’re looking for with our radio telescope is a signal that doesn’t look like the kinds of signals that nature produces, so when natural sources of emission like pulsars or molecular clouds or hydrogen gas emit radio signals they spread it across the spectrum... Sometimes it’s relatively limited. Sometimes it’s completely broadband, but we have the ability with our technology to create a radio signal that is a single tone, a single channel on the radio dial if you wish and it’s very detectable against the background noise if you have the right detectors, so that is what we’ve been looking for, something that is obviously engineered, something that nature, at least as far as we know, can’t produce. Now that may be the wrong thing. We might have guessed wrong. We might... as we get more computational capability we might be able to look for other kinds of signals that occupy more of the spectrum, but still appear different than the signals that natural sources emit. So if you can imagine a two-dimensional screen and it’s full of snow and static like an old analog television set, which wasn’t getting good reception. But on that two-dimensional display imagine a line that is drawn and it can be straight up and down or it can be slanted and if that screen is displaying two dimensions, one of frequency and one of time that line would be a signal at a single frequency and if it was straight up and down that frequency would be constant. If the line has a slant to it the frequency is changing in time and that might well happen because the transmitter is accelerating with respect to the earth. 

We’re also now beginning to look in the optical part of the spectrum, not just the radio. Whereas in the radio we look for frequency compression, we look for narrow signals, in the optical what we’re looking for is time compression. We’re looking for really bright flashes that last a nanosecond or less. Now as far as we know, again, that is the kind of thing that nature can’t do. But with the right detectors even when you’re looking directly at a star you can see a bunch of photons showing up in a single nanosecond against the background and if you found such a thing it would certainly suggest a technology, an engineered signal. 

Question: Are we broadcasting any signals that would help extraterrestrials find us? 

Jill Tarter: On earth we currently leak a lot of signals, broadcast television for example, radio. The signals are intended for our local neighborhoods, but in fact, many of those signals go on beyond the earth and travel and spread out in a bubble around the earth that gets bigger one light year per year, so we’re announcing our presence inadvertently. That is going to change in the future as we change our means of broadcast technology and go to direct TV kinds of deliveries and digital, but actually even the satellites that are delivering the signals have some leakage out the backside of them, so we’ll never go completely radio quiet, but we’re not actually deliberately transmitting signals to different planets. We now know about 455 planets around other stars, so we’re now beginning to know about some of the places we might decide to transmit to, but we’re not doing that and the reason is we’re actually too young. We’re a very young technology in a very old galaxy, so with respect to interstellar communication we’ve had appropriate technology for maybe 100 years. The galaxy is 10 billion years old, so we don’t know whether there are any other technologies out there, but we do know that we’re the youngest that could participate in interstellar communication. Anyone younger than we are with less technical capabilities than we have can’t yet be part of a conversation. And the odds are in a 10 billion year-old galaxy that anyone else’s technology is a lot older than ours, so right now it seems to me that it’s appropriate to let the older technology do the heavy lifting. Transmitting is harder than receiving, so we’ll put that job on them. Then if we ourselves get to be an old technology, if we grow up, if we in fact can get ourselves organized to be able to take on projects that last not 2 years or 5 years, but 10,000 years or 100,000 years, which is really what you need to do if you’re thinking about transmitting purposefully, then when we’re older it would be appropriate for us to begin to transmit. Of course, by then I hope that we could answer the question about who should speak for Earth and what should they say. 

Question: What will we do if we detect a signal? 

Jill Tarter: We do plan for success, so at every observatory we’ve ever worked and now at the Allen Telescope Array, our own telescope we keep champagne on ice. We intend to celebrate if we have a detection and then of course there is a lot that needs to be done. First you need to verify that what you’ve detected is actually what you think it is. With SETI, because it is so attractive to so many people, you have to worry that it might be a deliberate hoax. So we have to take precautions and one of the easiest things to do and one of the most sensible things to do is to call up a telescope to the west of us that has the capability to detect the frequencies that we’ve detected and ask them to go looking with their equipment to see if they see a signal. If they can confirm that they can see something with equipment that we didn’t build and software that we didn’t write, than it is a pretty good independent confirmation that it’s a real signal and it probably is exactly what we think it is—either that or it’s a whole new brand of astrophysics. That could happen, too. We’re looking for signals of a particular type because we don’t think nature can make them. If we find that kind of signal, it’s either the engineering we’re looking for or something amazing and new about nature, so we’ll try and get that independent confirmation then we’ll go through a whole process where we first send out an IAU telegram, which is essentially an email to all the world’s observatories and it says, “Here is what we found. Here are the details about the discovery.” And any observatory could, in fact, choose to look with whatever equipment they have to see what else might be there. But the other thing that does for you is informs your scientific colleagues about the details and these are the people who are most likely to be reachable by the world’s media and journalists who when we make an announcement and we certainly will hold a press conference and tell the world. When that happens the world’s media are not going to be able to call up the SETI Institute and get a comment and we don’t want to leave them without some authoritative source. So by sending out this telegram to the observatories around the world, the discovery information is in the hands of people who can hopefully help interpret it to the journalists, to the media, and we don’t leave them awash in making up their own stories. Then of course we do tell the world. We first probably make some very discreet courtesy calls to our major donors to let them know what is happening. We’ve never been asked to do that, but I think as a thank you we certainly would and then we try and hold a press conference and try and make sure that everybody who had anything to do with the discovery is appropriately credited... and then I don’t know what happens. That is as far as we go in terms of planning and thinking. We’ve tried to put a little effort into "Gee, how do we keep our phones working and our Internet up, right when we expect a huge deluge of people wanting to know more." And how the world will react is a guess. Maybe it will be as Carl Sagan pictured in “Contact.” Maybe it will be different. 

We’ve actually held some workshops, brought in some experts from the diplomatic religious journalistic communities, social scientists and said, “How will the world react to this news?” At the end of the day, what could we say? We said that people will react in accordance with the belief systems that are in place at the time. It doesn’t tell you a lot, so I guess the other thing that came out of these workshops was the importance of trying to educate and inform people in advance that this is a possibility. This could happen. This could show up on their television screen or in their newspapers tomorrow and they might be thinking about what that means for them and that is another avenue that we’re trying to go down right now. 

Question: If you had to send the message, what would you say? 

Jill Tarter: I would be so overwhelmed and excited simply to have an answer to this old question, even if there is no message, even if it’s just kind of a cosmic dial tone that’s a proof of existence. I mean, good heavens, we’ve answered a question that we’ve wondered about for ages and it’s interesting because in this field the number two is really, really critical, so we have one example of life, life here on this planet. We don’t know about any other, but the moment you get a second example then you know there are many. In physics we tend to count one to infinity, so with a single example it could be unique. The moment you get a second, you know it’s abundant. So the moment that we find that evidence of the second technology we’ll start looking for more because we know they’re going to be out there and so understanding actually how we fit in, what the diversity is, what physics and chemistry have managed to concoct other places, what other kinds of biology. That is what interests me rather than sending a message about us. I’m really interested in them. 

Question: If you were an extraterrestrial looking at Earth, what would you think? 

Jill Tarter: From our leakage radiation, our broadcast television and radio you can tell some amazing things about the planet and the technological species that occupy it. You can certainly get the length of our day. You can get an estimate of the size of the planet. You can even deduce that we don't have any kind of global governance. That is because in every region of the planet, television stations and radio stations are assigned frequencies that are specific to the different international telecommunications union regions around the globe and those frequencies are similar, but not exactly the same, so if you were getting the broadcast transmission leakage from this planet as our planet rotates and another region comes into view on the horizon you would see that those transmission frequencies shift a little. In 24 hours they’re back to that same pattern and you would probably deduce that the whole planet was not operating as a single geopolitical unit. So we talked a little about... and we often think about what is going to happen if we detect a signal. Certainly the SETI Institute is part of a group of scientists who are working on the project who have said, well you know if we detect a signal we’re certainly going to tell the world, but we’re not going to transmit back until there has been some global consensus that we should. Then we figure out who should speak for Earth and what should we say and that is all great... really hard to understand how we’ll do it. And at the same time if you announce that you’ve detected a signal and you give the nature of the signal you let other people know what you’ve found, then it’s human nature. Anyone who can have access to some kind of a transmitter is going to use it and they’re going to say whatever it is that they want to say. Whatever we might want to have in terms of this high minded intellectual response. And Freeman Dyson, a physicist in Princeton at the Institute for Advanced Studies, kind of chuckles every time we get into this topic. He said, “Think about it. That un-orchestrated, chaotic, cacophony that would emit from the planet after the detection of a signal.” He said, “Wouldn’t that be about the best representation of 21st-Century Earth that you could imagine?” And I have to agree that he is right. Nevertheless, scientists that we are, we try and plan for that. There is a piece of our website at the SETI Institute, at, a project called "Earth Speaks." One of our scientists is trying to get people—particularly young people—to tell us what message they would like to send if we were going to send a message to another technologic civilization and what he is looking for are cultural universals, the kinds of ideas that come from every society around the planet and it’s a way to try and see what, at the core, it is to be human and what we’d like the rest of the universe to know about us. 

Question: Why are women so underrepresented in engineering? 

Jill Tarter: I don’t have a lot of female colleagues. It’s getting better. That is the good news. The gradient is in the right direction. It isn’t yet 50/50 or it isn’t yet really representative of the intellectual capacity of our planet. I think engineering is probably the least represented with a female population and I’m not quite sure why that is, because engineering problems are phenomenally interesting and challenging, and it’s a creative profession. So I think it’s a shame. If women ran the world, different things would be engineered and invented. And I think it is a shame that we don’t take more advantage of them, but as I said, it’s getting better and it has to get better with young men as well as young women. I think one of the real challenges is if you’re a woman in science, engineering, mathematics field you’re overwhelmingly likely to be married to someone else in that kind of a field, right? Because those are the people you meet. You’re an underrepresented population. The folks that you meet, your male colleagues are likely to be your spouses. Then we have a problem, what we call the two-body problem, finding suitable positions, two jobs for one couple in the same area. That is a real challenge and we still have a tradition in this country where it’s more likely that if one of the two professionals ends up sacrificing a position or taking a lesser position it’s more likely to be the women. Got to change that. Of course it’s much easier to be creative in terms of jobs and making opportunities when the economy is doing very well. It’s much harder in a tight economy such as we have now, but we need to be creative. Women hold up half of the sky. How can we not involve them? 

Question: Have you faced any challenges as a woman in science? 

Jill Tarter: When I was getting my engineering degree, I was the only woman in a class of 300 guys and that had a lot of challenges. I had a nuclear physics course where I was asked to leave the room the day that they discussed health hazards of nuclear reactors and sterility for my male colleagues. I don’t know. It wasn’t appropriate for a woman to sit in the classroom and discuss. As if I, as a woman, wouldn’t have had any health issues if I had gone into that field, sort of silly. A lot of other things, but you know that was then and somehow I had enough stubbornness to make it through and I’m incredibly fortunate to have a career as a scientist and be able to blend my long-ago engineering training with what I’ve learned about the natural universe to try and craft a better search program looking for signs of someone else’s technology. It’s really a privilege to be a scientist. First of all, you never have to grow up. You never have to stop asking why. You get to pose your own questions and try and find your own answers and you get to do something tomorrow that you couldn’t do last week or last month. You get to learn new things almost every day. You get to learn something new about something and, gosh, that’s a real privilege. I like to tell young people that being a scientist is very much like solving mysteries. We’re actually trying to be the first person to understand something. Other people may have worked on it, but there are problems that don’t yet have answers and we could be the first ones to figure something out.
Recorded on June 3, 2010
Interviewed by Jessica Liebman