Jill Tarter - Technosignatures: What Are They, And How Might We Find Them? (TechnoClimes 2020)
Okay, well again apologies. For not being. Um on time but let's see what we can think about and, i'm really interested, in this workshop, because, i've been talking about this for a while, and, i'm tired of my ideas. I'm really interested, in new ideas. So, biosignatures. And techno signatures, you just heard a nice talk, by edward about, some of the differences, there but. Um. I think, that. Both. Are. Reasonable. Under, an astrobiology. Program. And. It's been. Frustrating, for me, that. We have been excluded, for a while, so. What we're trying to do is find, habitable, worlds, through the actions, of the inhabitants. And. We started with a search for communication. So we've had 50 years of, plus of of seti. In the optical. And the radio. And, we've been looking for obviously. Engineered, signals. Meaning, that we've been looking for frequency, compression. And or time compression. That nature, does not permit. So we've looked for a single frequency, on the radio, dial, a. Single. Nanosecond. Pulse in time. And. More recently, for monochromatic. Lasers, setting. Beams, with. Embedded, information. So. There are, um. Two kinds, of signals. That, we could imagine. There are the signals, that are almost, natural. Which we would catch. In, a. Large, astronomical. Search. Of the. Heavens. And then there. Are. Things, like. For example, a pulsar. That had, a single, period. And then switched its period. And then. Changed its period again. And then again, so we found pulsars, that have, a change in their period because of starquakes. But we've never found one that went from period one to period two back to period one and then period two again but if we, they they would show up. In, our. Databases. If we, analyze, them, and that's almost natural. So, we've also, just been talking about transits. Of planetary, transits, and what you could see, through their atmospheres. But. Um. One of the things that the. Iau, has told us is that planets. By definition. Are. Spherical. And so the shadows, on their. Uh. Stars. Would, have a particular. Look, in their. Light curves. But indeed, if there were artificial. Transients. Things that were, put there. To look, unlike.
Natural, Planets. You could find. That information. In, the, um. Higher, orders, of the, spectrum, in, the light curves, at, ingress, and egress. So. Uh. We could look for that the other thing is, how about, star tickling, how about taking a cepheid, variable. Which has a normal, period. And, as it expands. It gets brighter, and then it contracts, and gets dimmer. How about, taking a cepheid, and. Just as it is in its dim phase, and thinking about, getting brighter. How about zapping it with some energy. Neutrino, beam or something else, that, makes, it expand. Prematurely. Now you've got, a, morse code, cepheid, you have a sepia with a normal period, and a short period, and they can be seen. For, example. Across. The, um. The galaxy. And out to the virgo cluster. Another, idea. Is. If you've got time, if you're not in a hurry. You could take. Some material. And. Inscribe. Information. At almost the atomic. Level. And then throw rocks. Among. The. Stellar, systems, and planetary, systems, and, you might in fact. Be able to discover. One of these, strange. Meteorites. In your collection. Such as we have pieces of mars and the moon, within, our meteor, collection. And discover, that there's information. Content, there, so those are almost, natural, you don't have to do anything. More. Than. Look at. Data that you're collecting. In, the way that you would normally collect it for astronomy, and astrophysics. Um. We've had. 50 years of of. Searching. Of seti to date, for. Communication. Signals. Um. 60, years on, it's more like, a, little. Hot tub rather than a glass of water. And we. We. Live in a, multi-messenger. Universe. Right there are. We've been looking for photons, for a long time, but now we know. That there are, other. Messengers, that can. Carry. Information. Between the stars, and we've begun, to think about. Looking. There. Um. On the other hand, given the, funding, levels. That seti is likely, to. Uh. Address. Um or be. Able to access. I think it's. Really. Correct to say that. And here here's, michael hipke's. Really, nice, uh. Analysis, of the different ways that we might be able to get. Information, across the universe. I think it's relatively. Safe to say, that in the near future, we're still, going to be stuck with photons, and electromagnetic. Waves as we're looking for techno signatures. So. What can we do, we can look for artifacts. And, it's now, feasible. Only. Within the solar, system. Um. And, on earth. History, recorded, history. A few thousand, years. Archaeology. Gives us a few, ten thousand years, and, geology, resurfacing, the planet, means that. Artifacts, are going to be around, only for about 100, million years. And, now, there's, a recent. Suggestion. That. If we weren't looking. For electromagnetic. Indications. Of techno signatures. If we were thinking about neutrinos. As being, our information, carrying.
Particles. Then. Although we can't. Find. The neutrino. Beam, itself. In our laboratories. We might, in fact be able to. Detect. The presence, of a modulated. Neutrino. Beam. Because. It would change, the rate, of. Decay. Of. The manganese. Radioisotope. 54, manganese. In the lab. That's. That's a bit of a. Wild card but, indeed. Maybe. That would be an indication. Of someone. Uh, providing. Us. An artifact, in our laboratory. With a neutrino, beam. All right on the moon. We haven't. Been able to search. Subsurface. Or, for features, that are less than about 10 meters in, scale. And, um. In the solar system itself. We should think about. Looking, for. Artificial, lighting or trans. Transmitters, on asteroids. Or. Ice flowers on comets, as freeman, dyson suggested. And then. These, l4, and l5. Lagrange, points, in our earth. Sun. Solar. System. There's been a suggestion. That, something called the cartelski. Clouds, which some people see and some people, fail to find. Might in fact be. Filled, with, manufactured. Probes. Made by, molecular, manufacturing. That could be little dimenoid. Nanobots. We've. Recently. Been, intrigued. By. Amumumua. And. Are now thinking, about the fact. That. This might, represent, something, that we've, long known in science fiction. Which is um. Rendezvous, with roma, a distant, spacecraft. In our solar system. And so. We've all, looked at a. Number of. Teams have done that, looking for artificial, transmitters, on that body. And, um. We've been. Intrigued, to think about. Within our solar system. Looking, for. Space. Archaeology. That. Worlds that are dead at their own hands. Bio. Biology, can kill a planet, as well as. Technology. And so. Um. We've, had to, assume, that we can. Then. Not just, look within, our own, solar, system. For artifacts. But in fact. Bodies entering, the solar system, might give us. Access. To other solar systems. So. Let's think about what technologies. Do and how we might look for them. Um. Okay we can harvest, energy, to do work, and then the question, is what kind of energy. Is being used. So the observable, consequences. For different energy, forms. Edward just mentioned. Uh, the. Different. Carbon. Fluorides. Like carbon. Compounds. That are, the pollutants. Of, our own technology. Might. Actually. Uh. Grace. Other. Atmospheric. Solar system, atmospheric. Compositions. Of different. Distant, exoplanets. But. The amount of observing, time.
That Is, required. To go looking for this kind of, pollution. Of. The milky way is. Quite exorbitant. Unlikely. To be. Obtainable. But. Who knows what will happen, when. Jwst. Finally launches. If it's um. Fissile waste. If it's nuclear, fission that's the. Source of energy. Then we can think about. The disposal. Of fissile waste. Into, the host star. And, if anyone, was doing that with sufficient. Volume, then you could. Imagine. That you would get an enhancement, of. The rare earth elements such as presidential. And neodymium. And schebelski. Star, is one example. Where you have. Such an increase, but. No one has yet, suggested. That this really, is. Evidence. Of, uh. Nuclear, technology. In a, distant. Star system. All right if it's, tritium. If it's fusion, rather than. Fission. Then. There might be tritium, leakage. That would be, uh. Detectable. Because tritium, has the equivalent, of the 14, 20. Uh, megahertz. Line, of. Hydrogen. At uh. 15, 16, megahertz, but the half-life. Of tritium, is so short. That if you found, that lint, line emission. Anywhere, except, right, around, a recent supernova. You would have, a, very, puzzling. Piece, of, potential. Techno, signatures. To. Explain. All right. Other kinds, of work. Well, tran you we, use, to. Transfer, information, is one of the things that we use energy to do. And when in fact, the first gamma-ray, bursts, were found, we wondered. About. Whether. Um. Those might be, the annihilation. Accelerations. Of photon, rockets, right, half an mev. Of. Uh. Matter, anti-matter. Annihilations. And. It was also suggested, that if it's not. Relativistic. Travel, but very slow, ships. Then, they might stop off in our solar, system. To, replenish. Uh. Materials. In which case. They might be in the asteroid, belt. Orbiting. Some, asteroid. And so a. Double. Asteroid. Would be a really, interesting. Detection. But, in fact, we've found double asteroids. And, so far they're just a couple of rocks. So. Not, terribly, interesting, as techno signatures. And finally. We. Have been, thinking, about. Uh. Laser, acceleration. Or, microwave. Acceleration. Of. Targets. To, get near the speed of light, to do, interstellar, exploration. And so. Something, like. Breakthrough, starshot, lasers, are visible. Across, a vast, array. Of space, and we should be looking, for that kind of. Consequence. Of doing work. And, faster than light travel, well. I can't i put this up because you can't ignore it but i don't, know, what the. Observational. Consequences. Might be. All right, so now. We think about. Observational. Consequences. Of. Husbanding. A planet. And how would we tell. A natural, versus, an engineered. Exoplanet. Right so it might have. Um. An unexpected. Albedo. Or glint. From, orbiting, mirrors, it might have a. Surface, temperature, that's, wrong. For its. Distance, from its have, its, host star. It might. In fact. Lack extreme. Weather, because, that's more comfortable. For, advanced, life but i don't know how you would detect that. And finally. If. You think about, it might have. Latitudinal. Homogeneity. Right you might have, changed, your weather, so, your whole planet. Was. Benign. And, uh. Suitable, for, your. Habits. And then what about. Having. Multiple. Identical. Planets, within one solar system suppose, when. We get these 30 and 40 meter, ground-based. Or. Advanced. Orbital, telescopes, such as havocs, or luvoir. Suppose, when we look at something like the trappist-1. System. We see. That. Three or more. Of, those, planets. Are all the same. Suppose. That there's been some geoengineering.
Within The system. That has, rearranged. With a great deal of energy. The surface. Of. The planets. So that there's, more, potential. Habitable. Real estate. Than there was initially. Might we disguise. That there were some. Are. Some. Engineers. Out there. And. What about. Having. A. An incredibly. Well-populated. Geosynchronous. Belt. Something called a clark, exo belt. Around, your, planet. Something, that was at the same radius, but extended. In height. And. Was populated. With enough density, that in fact. When you looked at the light curve. From, reflected, from such a planet that you could detect. All of these. Services. In, geosynchronous. Or, geoplanetary. Orbits. And finally, if you do enough, modification. In, a. Solar system. You will eventually. End up. Having an influence. On, the star. Itself. So. In terms of these mega structures. You would, see. An infrared, excess. Versus, the stellar, type. You might see the star. Over, centuries. Disappear. Because, the light is blocked. By, megastructures. And finally. You might end up, having, a population. Of, stars. Whose spectroscopic. Distances. Are greater. Than the parallax, distances. That we get from gaia, and its, subsequent. Missions. Because. You've actually. Dimmed the star. With your megastructure. As i said before. You might end up getting glimpse. From, orbiting, mirrors. That are used, to warm the dark sides of tidally, locked exoplanets. Or. Somehow. In looking. With, incredible. Resolution. At, distant, exoplanets. You might, find. That there's some evidence, of, resource. Extraction. From, their asteroid, belt. And finally, if you think about. Whether. Biology. Actually, ends up turning, into. Technology. And the biological. Entities. Are replaced. By. Machines. Then you might think about. Well. Suppose. That. Um. A super intelligent. Singleton. Is, improperly. Contr. Constrained. And given. Um, a goal, for example. To make a million. Paperclips. Well. That. Singleton. That. Machine intelligence. Is only going to be able to decide that it has, fulfilled. Its goal. On a statistical. Basis. And so, it will. Um. Never be quite sure and so. It will make more paper clips and eventually. It will, turn, everything, into paper clips or paper clip manufacturing. Capability. And so. A uniformity. That is, uncharacteristic. Of a stellar system. Might in fact indicate, the presence, of, a. A distant, technology.
Okay So, this is generalized. Artificial, intelligence. And, where. Would we look for it. Well, it needs, an energy, source so it might. Surround, a host star. And. You would see, a. Thermal. Infrared, excess, and then you, would also, be expecting, to see signals, between. This montreal. Brain and others. And. Um. As you go out from, the. Central, source of energy. The next gen the next, ring of computation. Would be. Powered, by the heat loss from the inner, ring. And, so you need to think about, where might these kinds of. Computational. Engines, be placed, well. How about. Next to sources, of of a lot of energy, like black holes or neutron, stars, and. I remember the pulsar, planets, that we first, found, before we found, actual planets. Terrestrial. Kind of planets. And i wonder what the explanation. For those might be. Or, you might expect, these kinds, of. Technologies. To be at the edges. Of, the milky way galaxy. Because. They have, access, to colder. Regions, around them and it's easier, to exhaust. Their waste heat. So, lots of things to think about with respect, to the observable. Consequences. Of, of doing work. Uh. And, the thing that's really, fantastic. Right now, and why it's, wonderful, that we're having, this. Workshop. Now. Is that, there's, a huge, opportunity. For, improvement. Right, we've got, lots. Of fast computing, we are beginning, to have access to the transient, sky. We. Could perhaps. Detect, neutrinos, as well as photons. Indirectly. We're beginning, to be able to use, artificial, intelligence, and neural networks. To. Look at the data. In a way, that's, um. Agnostic. We're not telling it anymore, to look for particular, patterns in frequency, and time we're asking. The artificial, intelligence, to tell us whether there's anything anomalous. Within a particular, data set, there's. Lots of data sets. And the opportunity, for data mining. There's, uh. We're beginning, to bring, in. The social, scientists. To help us understand. How. Perhaps, better to look, for evidence, of technology. And, we're, beginning, to have. Formal. Instruction. At the university, level. For. Undergraduates. And graduate, students and and therefore. Expanding, our community. So. We've built, some. Specific. Telescopes. To look. For. Techno signatures, like the allen telescope, array, and breakthrough, listen, is. Putting. Enhanced, back ends. On. Otherwise. Existing. Telescopes. From the radio astronomy, community. And, there are. Um. Searches, going on, we're not quite sure what's going to happen with arecibo. Now that, breakthrough. Um. The the study at home has, collected, an enormous amount of data and is. Stepping back and rethinking. How. They're going to use that data. Rather than necessarily. Capturing, more but we can imagine. That there will be other, commensal. Searches, on arecibo. Um, lofar. Two, telescopes. Uh two two locations. Of the lofar, array. In sweden and in ireland, are beginning, to, look for low-frequency. Transients. A, telescope, in sardinia. Is beginning. To work, on seti. The. Down, at the deep space network, in, um. In southern california. They've moved, one of the. Telescopes. Outside, the fence. And. Now we have the goldstone. Apple valley. Radio, telescope, that's being, run by students. To do a sky, survey. And the melora, whitefield, array, is, also, beginning, to do sky surveys, at low frequencies, for seti. Um optical, seti. Harvard. Specifically. Built telescope. All of the data, that's being taken, at, keck, for, radial velocity. Studies, of exoplanets. Is also, being. Re-analyzed. Looking, for, engineered, signals. There's. Amateur. Telescopes. In. Panama, and elsewhere. Doing, optical, study. The. Lick observatory. Has moved optical, seti into the infrared.
And, It's also, possible, to do archival. Seti, as the cheat, ghat, survey, of wise. Um, has done looking, for, check two and, keck three, i'm sorry kardashev, two and kardashev, three, types of civilizations. We've taken, the, veritas. Gamma ray observatory. And. Written, new, software. So, that. We're looking, at, individual. Pixels. In the. 500, pixel cameras, of these. Telescopes. Which light up on the sky, all. Simultaneously. Uh. In the optical. Shelly right, in, in san diego. Is. Looking, at these half meter fresnel, lenses. Focusing. A large, area, of the sky. Onto. An array. Of, detectors. That are. Now. Possible. Looking, at um. Their. Oh i'm forgetting the name never mind. Um. So we have. The idea, of building. A, uh. A. Geodesic, dome with these. Lenses, that are focusing. A large piece of the sky, onto. These. Uh, photodiodes. And being able, to look at a large, area of the sky, at the same time. And the first, two, of these. Elements. That would go into a geodesic, dome. Are. Now, exist. At. They've been installed, at lick observatory. And there being. Engineering. Testing, is going on. Another, idea. Is not a. Big dome not a big telescope. But an inexpensive. System. Based, on. Cameras. That, um. Is being. Worked on by elliot gillum at the seti institute. And the idea, is. Again. Looking, at all the sky. Above the horizon. And, looking, for, fast. Monochromatic. Pulses. So. With the. Gratings, that elliot has in place. You can see that continuum. Sources, are spread out. Across, the detector. Whereas, monochromatic. Sources, have. Individual. Points, that, make them, quite detectable. And when you actually put this on the sky. For engineering, tests it's a lot more. Noisy. Than that nice, uh. Conceptual, layout, that i just showed you but the, first. Half observatory. Is now in place at ferguson. Observatory. In, northern california, in sonoma. And the next, observatory. If we can figure out how to do the quarantine. We'll go on haleakala. In hawaii. And so you can see that spread across, the globe, about, 15. Sites. Will give you full sky coverage you're looking at all the sky, all the time. For these kinds of transient, signals. And, here's something. Which has been proposed. By, um. Jeff kuhn in hawaii. And it is more like. Uh, an inter a radio interferometer. Than it is a standard, optical, telescope. But if you phase up these, collecting. Areas. You can in fact, over, many. Orbital. I'm sorry many, um. Cycles. Of planetary. Orbiting. Around, its, pro, primary, star. In fact. This. Single telescope. Would look at the proxima, centauri, system, and probably, nothing else. But with enough, orbital, periods, you can in fact. Deconstruct. The light curves, to give you an image that would allow you to detect. Cottons. And just, distinguish. Them them from oceans, and do. Searches. For, biosignatures. At specific, locations. On, that nearby. Exoplanet. So we're looking to the future we're looking to the things. That, the, astronomical. Community. Is talking, about, building. The. The 30 and 40 meter class telescopes. Uh, the. Um, this, large synoptic. Sky telescope. That will give you an, image, of the sky, every. Few days. To look for things that are changing. And we need to think about. How. Seti. Can. Commensally. Observe. With these new, instruments. In. The optical. And, also. We're looking about, the. Exploring. Expanding. Panel seti and laser setting which near which is fully funded. And, we're thinking. About. How, to, uh, improve, the kinds of searches that we can do with the veritas, telescopes.
And, In the. Radio, we're thinking, about. Meerkat. And the square kilometer, array. To be, meerkat, is now functioning, square kilometer, array hopefully, in the next decade. And, the fast, telescope. In china, is beginning, to have back ends. That. May allow us to do, much more sensitive, radio searches. If we're lucky, the next generation. Vla. Will also. Allow us to do seti. And if we ever make that. Elf telescope. The exo life finder work. Then this is its big brother colossus, which will be able to find the heat signatures. Of, the equivalent, of cities. On. Nearby, exoplanets. Jwst. We've talked about what it could find in terms of pollutants, in the atmospheres. We're thinking about the roman telescope. And, perhaps. In the future a star shade to go with. Telescopes. Like that, havocs, or, luvoir. These will give us biosignatures. As has been said in the previous, talk. And. There's this enormous, suite. Of exoplanet. Missions. That will. In. Give us, new information. That we can, interrogate. For, potential. Techno, signatures. As well as biosignatures. So, there are lots of opportunities. To look for life, and. Technology, beyond earth. And i think that it's really important that this whole community. Continues. To talk about these opportunities. Because we have all of these global, challenges. On this planet. If we're to have a long future. And. I think, that. Projects. Like. Seti. And the search for techno signatures, the search for biosignatures. Can help us see. Ourselves. In a mirror. That, shows us that, across, this, particular, planet. We're all the same when compared, to thinking about something that may have evolved. Somewhere else. And so, it trivializes. The differences, among us. And. That leads me to caleb, sharp's. Final. Words. But on a finite, world a cosmic, perspective. Isn't a luxury, it's a necessity. So, thank. You.