How are aliens searched? What riddles and problems does SETI face?

If aliens try to talk to us (orif they don’t try), Jill Tarter will find them first. She founded the Institute for the Search for Extraterrestrial Intelligence (SETI) in 1984 and led its research center for many years. Inspired by her work, the director made the film “Contact” (1997) with Jodie Foster in the title role. Astrophysicist Maggie Turnbull, who currently works for the Wisconsin Governor, began working with Tarter in the late 90s and is now affiliated with the SETI Institute. She is working on the NASA WFIRST telescope, which will go into space in 2025.

These two scientists have a slightly different approach tosearch for extraterrestrial life. Tarter focused on finding evidence of advanced alien technology, while Turnbull is looking for biological signatures. Wired magazine talked to scientists at a 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.

Finding Aliens: SETI and NASA

What properties that can make a system potentially habitable are you looking for first?

Turnbull: First, longevity. The brightest stars burn their fuel the fastest and they will burn their hydrogen reserves and swell to the red giants long before the planets appear. These stars are not in the target list. In addition, if a star does not contain any heavy metals, if we assume that the planets are formed from the same material from which the star is formed, there is less chance of finding planets in this system. So metal poverty is also bad.

In space research, there is a kind of bifurcation between the search for biological signatures of life and the search for technological signatures. Can you determine what it is?

Tarter: SETI is looking for extraterrestrial intelligence, but we have no idea how to detect the mind directly. Therefore, we take the technology at our side and ask: “Are there any technologies out there that change the environment so that we can detect this at interstellar distances?” If we can find any technological clue, we would assume that at some point there were also intelligent technologists who created it.

Bacteria dominate this planet. Microbiological life is much more prolific than a complex life, and perhaps it will be so elsewhere. Perhaps we should look for germs before we find a complicated life.

But now do these areas converge a little?

Tarter: Throughout history, we searched for signals in the electromagnetic spectrum. This was done by SETI. More recently, given the advent of the new ground-based telescopes we are building and the new space telescopes we are building, we thought: how to use them to find something that only technology can do?

Signals still seem like a good idea, butthere may be many other things that we will find. The astrobiological community was schizophrenic for a while, and it was normal to look for microbes at the beginning of a complex life. Then they said: "No, SETI, this does not apply to astrobiology." But now we had to reconsider this again, as astronomers are preparing for the next ten-year review of all the details that we can sit down and put in priority. And the committee of the National Academy of Sciences looks at the strategy of astrobiologists, and he is more inclined to accept the idea that both technosignatures and biosignatures fall under a large umbrella of astrobiological observations.

What are your favorite examples of possible alien technologies that are potentially discovered by our tools?

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 fit 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. 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 will find out that they are similar. That they have the same temperature. They look exactly the same. This is unlikely, given the freaks of nature, but if any technological civilization arises on one of these planets and decides that it needs more real estate, it can, in fact, transform all the planets in its system, make them the same.

Maggie, tell us about the telescope you are working on and what it can detect.

Turnbull: Right now my biggest and most comprehensive project is the WFIRST telescope. (Closer to launch, he will get a more fun name). But that means Wide Field Infrared Telescope. This observatory is for the most part designed to work with deep sky and search for dark energy and dark matter. The two most interesting topics in astrophysics ... But even more interesting for astrophysicists are exoplanets and life. Thus, as a demonstration of technology, we include the first born cameras in space to directly take pictures of nearby planetary systems. This has never been done before.

We plan to start with several planetarysystems, the existence of which they are sure for sure. We found them by the gravitational attraction that the planets exert on their stars. We never saw them directly, but we are sure that they are there.

What will you look 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 some green light. But for the most part, the 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 on why. Perhaps this is a cooling mechanism - and no matter what the point, it is really visible. The vegetation was clearly visible and there were signals that broadcast in the form of reflected sunlight in the universe over the past billion years. We could see it 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 launched [email protected] on their computers. (Many raise their hands). It has been working for more than ten years, and I think that this is what develops distributed computing and civic science together. SETI did not invent distributed computing. People used it to calculate Mersenne primes, but [email protected] they liked the fact that 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 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 an analysis of whether the signal really came from one point in the sky and moves like the stars do. Then a list of candidates is created from 10, 20 or 100 signals, then a request is sent to reserve time on the telescope to re-examine each of these places.

Attracting people to SETI is incredibly important andanother reason: it gives us the opportunity to change everyone’s point of view. It’s like raising a mirror and saying: “Look, everything, there, on Earth, you are all the same, when compared with something else that might be somewhere there.” And creating a global network to solve and work on this problem, I think it would be nice to touch on other problems that we have on the planet that are not related to national borders, but which need to be addressed systematically.

Blurring the differences 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 hundredsbillions of galaxies, each of which contains hundreds of billions of stars or something like that. So mathematically, statistically, there are a huge number of planets that support life. But there are also people who claim that life should have appeared on Earth as a result of a specific chain of events, and the possibility that this will happen again is infinitely small. Have you ever thought that you might have dedicated your career to finding something you will never find?

Turnbull: None. I like it when everything is in the palm of your hand. There are really good arguments for both possible answers. And I think that as a scientist, you should feel great with two possible options at the same time. It is like a quantum state that has not collapsed yet, but which you can imagine at the same time. “It cannot be that this happens again!” And “They must 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 inquiry that are relevant to 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 the limits of errors are exponential, so we don’t know, these are the limits of tens, hundreds or millions, this is not a theoretical science, this is a science that will make progress through observation. "

And if you say: “Good. We need to look for electromagnetic signals ”, now there are nine different variables that could describe such a signal. So, you have a nine-dimensional search space. Take this amount of search space and apply it relative to the 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, so much space we explored. Last week, students published a revision of this thesis and claim it now looks like a bath or a small pool. Much remains to be done. We barely started the search, it might not even be electromagnetic signals - it could be anything else.

In the movie "Contact" the character Jodie Fosterdiscovers 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 must note my bias because I attended that conversation with Karl Sagan, and my question would be: “How did you do this? How did you manage to go through the stage of technological growth 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 says that if there were so manyinhabited planets, we would probably get some evidence of this now. But we have not received. Because maybe they come in contact because they want to destroy you. And Stephen Hawking said that finding an extraterrestrial intelligence is a bad idea, because if they arrive, they will colonize us, as Columbus colonized the New World. What do you think about this?

Tarter: If you asked a question: “Is there a fish in the ocean?” And then they conducted an experiment, scooping a glass of water out of the ocean and didn’t find fish in it, I don’t think you would come to the conclusion that there is no fish.

This is also the Fermi paradox. We were just not looking enough to be able to tell if anyone was there. And Maggie stole my favorite argument against Hawking’s statement, which is that it’s hard to become an old, long-lived technological civilization without getting rid of aggression and thereby becoming reasonable in the first place. So if they arrive, to be honest, I don’t think we should 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 a little time on a series of radar studies of Lagrangian points. Many have suggested that asteroids could be a good place to place an artifact, so we are going to visit them. This is part of the search for tech signatures. We don’t know what we could find, so we’re just going to find out what is at the Lagrange points L4 and L5. What are these Kordylevsky clouds?

Jill, you can tell the audience what you think behind the curtains about some mysterious 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 do not know what it is.

Maybe it's just wormholes open andclose across 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 tools for its research.

Compared to the space program, are there any things that you create that find application in other areas?

Tarter: Some algorithms that we use to detect signals in real time have applications in other places. A long time ago, we were looking for a certain type of conversion - the conversion of radon - 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 that it is too expensive and not applicable on a commercial scale. 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 data without asking specific patterns for the search. We will let neural networks tell us if there is anything else besides noise.

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