Astronomer and former SETI director Jill Tarter talks about the future of our planet and why she ate so many ice cream cones when she worked at NASA. Tarter’s career was the basis for Carl Sagan’s 1985 science-fiction novel, Contact, which was later made into a film starring Jodie Foster. She talks about what it’s like to have Carl Sagan fictionalize her life, why we need to listen more than we talk, and why it’s important for us to think of ourselves as earthlings.
Tricia Bobeda: How did you first get your start with SETI? Why was the search for extraterrestrial intelligence a question that you wanted to spend your career trying to answer?
Jill Tarter: SETI itself was a bit of an accident. I ended up in astronomy and astrophysics. My first year as a graduate student, I was hired as a research assistant to program the world's first desktop computer, the PDP-8/S. Personally, I always thought the “/S” stood for “stupid,” because this machine had 64,000 bytes of memory and it had 11 instructions and no language. I learned how to program it.
Years later, I was still a graduate student, and this machine was obsolete. It was given to an X-ray astronomer, Stu Boyer, who had a very clever idea about how to use U.C. Berkeley's radio telescope to do SETI at the same time the radio astronomers were doing their traditional research. But he had no money.
So he went begging, and someone gave him this old computer. He said, “What am I supposed to do with this?” And they said, “You know Jill. She’s still here, right down there. Why don’t you go talk to her?” And he did! He came and recruited me to work on his project. And I was just overwhelmed.
I learned that after millennia of all of us asking the priests and the philosophers what we should believe about this very important, old question — “Are we alone?” — that suddenly, in the middle of the 20th century, we developed these tools that allowed these scientists and engineers to actually do an exploration to try and answer the question. To find out what is rather than what somebody tells us we had to believe.
And I was hooked. I thought, “Wow. I’m in the right place [at] the right time with the right tools and skills. I’m gonna go for this.” And I did, and I have.
Bobeda: You've mentioned that we’re such a young technological species. That the amount of time that we, as humans, have been able to listen and look and measure has been really not much time at all. Even in the last 20 years since the movie Contact first came out, what progress has been made in what SETI can do and what other researchers can do when it comes to those tools you’ve mentioned?
Tarter: Let me see if I can give you an analogy that quantifies how little. If you’re looking for signals, and that’s all you’re looking for — and that could be the wrong thing; there might be something else we should be doing but we haven't invented that technology yet. But if you’re looking for electromagnetic signals, then the haystack you have to search through is nine dimensional: three dimensions of space, one of time, two senses of polarization, what kind of modulation scheme, and lastly, you don’t know how far away the transmitter is or how powerful it is, so you don’t know how sensitive you have to be in your search to be successful. Nine dimensions.
All right, wrap that all up, that cosmic haystack, and say the volume of that space we want to search is equal to the volume of Earth's oceans. And we’ve been searching for 50 years, and we’ve been making better tools to do the searching.
So how much of that ocean have we explored? And the answer is, essentially, one 12-ounce glass compared to the entire ocean. Now, say your experiment was, “I wonder if there are any fish in the ocean. I’m gonna do this experiment. I’m gonna take a 12-ounce glass and dip it in to see if I've caught any fish.” In theory, that experiment could work.
But if you didn’t catch a fish, I don’t think you’d be likely to conclude that there are no fish in the ocean. Maybe you’d conclude that you need to start dipping a lot more glasses a lot faster. You’d need bigger glasses. And that’s where we are today.
Fortunately, the improvement in computer technology is able to give us an enormous exponential step up here, so that our glasses really are getting bigger. And what we can do is speeding up, and where we can do it is multiplying. So I’m really excited. Even though it’s a big ocean, I’m really excited to begin an exploration.
Bobeda: When did you first find out that Carl Sagan was writing Contact and that you might find one of the characters familiar?
Tarter: Well, Carl was a colleague. And I was at a meeting that Carl also attended, and he said, “Come on up to the house. We’re gonna have a cocktail party tonight.”
So I went, and he and [his wife] Annie took me aside and said, “Carl’s writing a science-fiction book.” I said, “Oh, come on, The New York Times told us last weekend how much money he’d gotten as an advance for this book, and we are jealous as hell! It’s just amazing!”
And they laughed and then Ann said, “Well yeah, there might be somebody you recognize in the book. I think you’ll like her.” I just laughed. I said, “As long as she doesn’t eat ice cream cones for lunch, then nobody who knows me is going to think that that character is me.”
Bobeda: Tell me more about these ice cream cones.
Tarter: Oh, those ice cream cones! We were working at NASA’s Ames Research Center. It was an old naval base, and there wasn’t much in the way of amenities. But it had a Baskin-Robbins on it! And so my colleagues and I would take a hike, and we would have ice cream for lunch every day.
Bobeda: If SETI picks up a reading, as they do in Contact, that sets a chain of events into action. What would that chain of events look like? How much evidence would you need to have to be sure enough to throw a flare up and get attention? How much evidence do you think it would take to get others to take it seriously?
Tarter: Well, for the programs we have running at the SETI institute, we have a set of protocols that we think we will go through. We have had a few false positives that have started us down those steps. The longest one lasted about 24 hours, and we never got to the stage where we called up the director of an observatory to the west who has the right frequency coverage and say, “Could you discreetly take a look and tell us what you see?”
Because one of the things we worry about a lot is a hoax. We’re a very attractive opportunity for hoaxes, and we want to make sure that someone using equipment that we didn't build and software that we didn’t write, can confirm independently our results. As I said, we’ve never gotten there, but we’ve thought it through.
And then, once you get an independent confirmation, you want to, as quickly as possible, arrange that the discovery information gets sent out to every observatory in the world to alert them to observe something that may be time critical. And you get all of your colleagues looking at this area of the sky, with whatever instruments they have, to see what else might be there. Then you fill in the blanks and get a paper off to a journal.
And then you begin the list of who will get attribution for all of this. You want to make sure you plan a press conference in which all of the many people involved over many years are appropriately recognized. And then you tell the world, because this information is not the property of the SETI Institute or any other discovery group. It’s the property of humankind.
Now, what I’ve just described takes a lot of time. And we hope that, if it is our telescopes that are involved with the discovery, we hope that we will have that time to work quietly and quickly to build that evidence base for an extraordinary discovery and announcement.
But we know from experience in that case with the longest lasting false positive, within 24 hours our offices in California were getting called by The New York Times asking what was going on. And nobody deliberately called them. It was just a series of coincidences that meant that someone could deduce that we were tracking a signal and we were interested in it.
Bobeda: Right now, SETI is focused primarily on listening. What do you think about the balance of time and energy spent on developing better ways of listening versus broadcasting?
Tarter: Well, if there are other technological civilizations in the galaxy, I think it’s probably pretty obvious that we are among the absolute youngest in terms of communicating across interstellar distances.
We're talking 100 years that we’ve been able to do anything of interest. And that’s 100 years out of a 10-billion-year history of the galaxy. Most of the stars in our particular area of the galaxy are about a billion years older on average than our sun. Our sun is a latecomer. So given that perspective, I think it makes sense for the young technology — the emerging technology — to listen first and see what's out there.
We get through our weekly planners or sometimes two- to five-year plans, but we haven’t done squat with 10,000-year plans. So when we’re young, we listen. When we get old and have the capability, then I think we should broadcast, and I think we should do so for the benefit of technologies out there that are emerging behind us.
This interview has been edited for brevity and clarity. Click the “play” button to listen to the entire conversation.