If aliens try to talk to us (or if they don't), Jill Tarter will find them first. She established the Search for Extraterrestrial Intelligence Institute (SETI) in 1984 and ran its research center for many years. Inspired by her work, the director directed Contact (1997) with Jodie Foster in the title role. Astrophysicist Maggie Turnbull, who currently works for the Governor of Wisconsin, began working with Tarter in the late 90s and is now associated with the SETI Institute. She is working on NASA's WFIRST telescope, which will go into space in 2025.
These two scientists have slightly different approaches to the search for extraterrestrial life. Tarter focused on finding evidence of advanced alien technology, while Turnbull is looking for biological signatures. Wired magazine spoke to scientists at the San Francisco festival. And although they are looking for slightly different things, both are convinced of the most important idea: the search for life outside our planet can unite us.
In search of aliens: SETI and NASA
What properties are you looking for in the first place that could make a system potentially habitable?
Turnbull: First, durability. The brightest stars burn their fuel the fastest and they will burn up their hydrogen reserves and swell to red giants long before planets appear. These stars are not on the target list. In addition, if a star does not contain any heavy metals, assuming that the planets are formed from the same material from which the star is formed, there is less chance of finding planets in that system. So metal poverty is also bad.
In space exploration, there is a kind of bifurcation between the search for biological signatures of life and the search for technological signatures. Can you define what it is?
Tarter: SETI is looking for extraterrestrial intelligence, but we have no idea how to detect intelligence directly. So we take technology at our side and ask: "Isn't there any technology out there that changes the environment so that we could detect it at interstellar distances?" If we can find any technological clue, we would assume that at some point there were intelligent technologists who created it.
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This planet is dominated by bacteria. Microbiological life is far more fertile than complex life, and perhaps it will be so elsewhere. Perhaps we should look for microbes before we find complex life.
But now these areas converge a little?
Tarter: Throughout history, we have looked for signals in the electromagnetic spectrum. This was done by SETI. More recently, given the emergence of new ground-based telescopes that we are building, and new space telescopes that we are building, we thought: how to use them to find something that only technology can do?
Signals still seem like a good idea, but there may be many other things we find. The astrobiological community has been schizophrenic for a while, and it was normal to look for germs at the start of a complex life. Then they said, "No, SETI, this is not about astrobiology." But now we have had to rethink it again as astronomers prepare for the next ten-year review of all the details we can sit down and prioritize. And a committee of the National Academy of Sciences is looking at the strategy of astrobiologists, and it is more inclined to accept the idea that both technosignatures and biosignatures fall under the big umbrella of astrobiological observation.
What are your favorite examples of possible alien technology that our instruments potentially detect?
Tarter: There is a fabulous star system or planetary system called Trappist-1. Seven planets revolve around a tiny dwarf star. They are packed very tightly: all orbits would squeeze into the orbit of Mercury if they were in our solar system. Three of them are at a good distance from their star, so if they had an atmosphere, they would have liquid water as well. Okay, now let's take these seven planets located at different distances from their star. And let's say that when we have the opportunity to explore them, we find out that they are similar. That they have the same temperatures. This is how they look identical. This is unlikely, given the quirks of nature, but if any technological civilization springs up on one of these planets and decides that it needs more real estate, it is, in fact,can transform all the planets in its system, make them the same.
Maggie, tell us about the telescope you are working on and what it might find.
Turnbull: My biggest and most comprehensive project right now is the WFIRST telescope. (It will get a funnier name closer to launch.) But that means Wide Field Infrared Telescope. This observatory is mainly designed to work with the deep sky and look for dark energy and dark matter. The two most interesting topics in astrophysics … But even more interesting for astrophysicists are exoplanets and life. So, as a technology demonstration, we are turning on the first born cameras in space to take direct images of nearby planetary systems. This has never been done before.
We plan to start with several planetary systems that we are sure of existence. We found them by the gravitational attraction that the planets have on their stars. We have never seen them directly, but we are sure that they are there.
What will you be looking for?
Turnbull: Water in the atmosphere has a very strong absorption capacity. Plants have a distinctive signature because they are very dark. We think they are green because they reflect a little green light. But for the most part, plants are very dark because they absorb all the light and use it as an energy source to build their bodies. And they also reflect in infrared, and there are many theories as to why that is. Perhaps this is a cooling mechanism - and whatever the point is, you can really see it. The vegetation is clearly visible and there has been a signal that has been broadcast as reflected sunlight in the universe for the past billions of years. We could see this on a terrestrial planet.
Maggie, you also work for the Governor of Wisconsin
Turnbull: I almost forgot!
What is the role of the public in SETI research?
Tarter: Let's ask the audience how many people have run SETI @ home on their computers. (Many raise their hands.) It's been around for over a decade now, and I think that's what is driving distributed computing and civil science together. SETI did not invent distributed computing. People used it to calculate Mersenne primes, but they liked SETI @ Home because they could use their computers to analyze stored data in search of a signal.
If anyone finds a signal, what will it look like?
Tarter: The computer will report some of the detected parameters. At the University of California at Berkeley, where they are processed, they will fall into a large filter along with other messages and go through the analysis of whether the signal really came from one point in the sky and moves the way the stars do. Then a list of candidates of 10, 20 or 100 signals is created, then a request is sent to reserve time at the telescope to re-examine each of these locations.
Getting people involved in SETI is incredibly important for another reason: it gives us the opportunity to change everyone’s point of view. It's like picking up a mirror and saying, "See you all, there on Earth, you are all the same when compared to something else that might be out there." And while creating a global network to solve and work on this problem, I think it would be great to touch upon other problems that we have on the planet that have no relation to national borders, but which need to be addressed systematically.
Blurring the distinction between us is the best SETI can do. This is the reason why we want to involve the whole world.
Astronomers would tell you that there are hundreds of billions of galaxies, each containing hundreds of billions of stars or something. So mathematically, statistically, there is a huge number of planets that support life. But there are also people who claim that life should have appeared on Earth due to a specific chain of events, and the possibility that this will happen again is infinitely small. Have you ever thought about the fact that you may have devoted your career to finding something that you will never find?
Turnbull: No. I like it when everything is in the palm of your hand. There are really good arguments for both possible answers. And I think as a scientist, you should feel great with two possible options at the same time. It's like a quantum state that hasn't collapsed yet, but that you can imagine at the same time. "It can't be that something like this will happen again!" and "They should be everywhere!"
I think we are talking about the brightest scientific field on the planet. She is so multidisciplinary. There are so many different lines of evidence and inquiries that go into the search for life.
Tarter: When I was a young scientist, Philip Morrison, one of the founders of SETI, told me: “Any topic in which error limits are in exponents, so we don't know if these are tens, hundreds or millions, this is not theoretical science. it is a science that will make progress through observation."
And if you say, “Okay. We need to look for electromagnetic signals”, now there are nine different variables that could describe such a signal. So you have a 9D search space. Take this volume of search space and apply it to Earth's oceans. How much did we research? When I made the calculations ten years ago, I counted about a glass of water from all the oceans of the Earth, we have explored so much space. Last week, students posted a revision of this thesis and argue that it now looks like a bathtub or small pool. There is still much to be done. We barely started our search, it might not even be electromagnetic signals - it might be something else.
In the movie "Contact", the character Jodie Foster discovers alien civilizations. During a job interview for a visit to aliens, she is asked what her only question will be for them. What would you ask?
Tarter: I have to point out my bias because I was present at that conversation with Carl Sagan and my question would be, “How did you do this? How did you manage to go through the stage of technological maturation, in which we are on Earth, and become an old, stable, technological civilization?"
Turnbull: I would probably ask: "How many, how many of us are here?"
The Fermi paradox states that if there were so many habitable planets, we would probably get some evidence of this now. But we didn't get it. Because perhaps they are making contact because they want to destroy you. And Stephen Hawking said that looking for extraterrestrial intelligence is a bad idea, because if they arrive, they will colonize us like Columbus colonized the New World. What do you think about this?
Tarter: If you asked the question, "Is there a fish in the ocean?" And then ran an experiment by scooping up a glass of water from the ocean and found no fish in it, I don't think you would come to the conclusion that no fish not.
This is also the Fermi paradox. We were just not looking enough to be able to tell if anyone is there. And Maggie stole my favorite argument against Hawking's claim, which is that it's hard to become an old, long-lived technological civilization without getting rid of the aggression and thus becoming sane in the first place. So if they do arrive, to be honest, I don't think we need to worry.
What happens when you look at our solar system, what kind of signatures and information do you get about our solar system?
Tarter: We spent some time doing a number of Lagrangian point radar surveys. Many speculated that asteroids might be a good place to place an artifact, so we are going to visit them. This is part of the search for technosignatures. We don't know what we might find, so we're just going to find out what's at the L4 and L5 Lagrange points. What are these Kordylevsky clouds?
Jill, can you tell the audience what you think behind the scenes of some cryptic signals
Tarter: We have a riddle in the field of radio astronomy - what are fast radio bursts? We think that at least 10,000 of these appear in the sky every day. They live a millisecond or less, and we don't know what they are.
Maybe it's just wormholes opening and closing all over the sky for transportation. That was my idea for the sequel to Contact. But these bursts are a real mystery, and we are trying to build a toolkit to explore it.
Compared to the space program, are there any things that you create that find applications in other areas?
Tarter: Some of the algorithms we use to detect signals in real time have applications elsewhere. A long time ago, we were looking for a specific type of conversion - radon conversion - and it turned out to be a great way to detect microcalcifications in breast cancer screening and mammograms. He passed the first stage of research. It turned out to be too expensive and not commercially applicable. But he finds patterns in noise. There are many different uses for this feature. Now we hope that what comes out of industry and university systems, neural networks, will help us sift through the data without asking specific patterns to search. We'll let the neural networks tell us if there is more than noise.
Ilya Khel
