Planetary Radio: Space Exploration, Astronomy and Science - Looking for ET's Flashlight: Optical SETI

Episode Date: January 12, 2009

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Looking for E.T.'s flashlight, this week on Planetary Radio. Hi everyone, welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. Paul Horowitz heads the SETI Research Group at Harvard. It includes the all-sky optical search for extraterrestrial intelligence. We'll get an update from Paul on that project in just a couple of minutes. Emily Lakdawalla is looking for the remnants of the Apollo landings on the moon in her Q&A segment. And then there's the terrible rocket accident suffered by Bruce Betts and yours truly

in today's What's Up? Look at the Night Sky. Who could ask for anything more on a space radio show? Well, you could start with Bill Nye. So we will. Hey, hey, Bill Nye the Planetary Guy here, Vice President of Planetary Society. And this week, the Obama administration is going to pick the next administrator of NASA. Now, if someone is an administrator, that doesn't sound like a big deal. But in the case of NASA, this is an old title. And it is a big deal. This person will shape space exploration perhaps for the next two or three decades, 20 or 30 years,

because the Obama administration is going to bring about great changes. Now, does it make any difference who this person is? I mean, the NASA budget is just not even a percent of the federal. Yes, it makes a huge difference, people. What we want is not somebody who is necessarily technically brilliant, although we don't want somebody who's technically not interested. We want somebody mainly who can inspire. That's what NASA should be in the business of doing.

See, it's one thing to plan to go back to the moon. It's one thing to decide whether three people are going to go back or six people or 12 or 15. Are we going to go on to Mars? No, we want people to get all of us, taxpayers and voters, excited, excited about space exploration, not confronting people about details that don't matter to most of us. Instead, we want people to get excited. Now, with that will come, I claim, a clear vision

because you will find out what people get excited about. See, that is what's going to change. If we can pick the right administrator, we can, dare I say it, change the world. So best of luck, Obama administration. I have a lot of people in mind. Oh, I'm sure we all do. But I am not at liberty to say, nor am I an expert. I just want somebody who's going to get us all inspired to explore space so that we can know our place in the universe

and know what we should do to protect our planet. It's going to be exciting. Well, thanks for listening. This is Bill Nye, the Planetary Guy. I'm the planetary guy. Paul Horowitz is professor of physics and electrical engineering at Harvard University. He also happens to be one of the leaders in the search for extraterrestrial intelligence, with a long history of innovations in that attempt to learn if we are alone in the universe. We recently spoke to him via Skype from the office where he heads Harvard's SETI Research Group. Paul, welcome back to Planetary Radio. It has been a good long while since we've

had you on the show, but we had a very good excuse to bring you back now because of your article that's featured in the current issue, the November-December issue of the Planetary Report, the bimonthly magazine that goes to members of the Planetary Society, there's a great review here of the All-Sky Optical SETI project that you had. And I want to know, first of all, if you're ready to tell me and the listeners that you've heard from E.T. Well, let's see. First, we have to call the New York Times. No, no, come on. Aren't we ahead of them on the list? I guess you should be, yes. Now, you do have a list, though, right? Is there a protocol? I think we've talked about this in the past. Well, you know, the space lures got interested in SETI back a decade or so ago,

and they decided that there should be a protocol, that this was so important to the people on Earth that we couldn't leave it to the scientists to do their science correctly. I've never gotten enthusiastic about this protocol because I think that SETI is really science. And like other sciences, it's self-correcting. The people who do it tend to be quite careful and know that if something they announce is not correct, it will be quickly discovered and corrected. I think it's best to let scientists do the science and let lawyers do whatever lawyers are supposed to do. Well, let's hope that the E.T. scientists are not being forced to consult with their attorneys either. But we do hope that you got the phone number and that we're high up on the list.

Tell us, what is the status of the OSETI project? Well, as you know, Matt, we're working on our second optical SETI project now at Harvard. The earlier one was our targeted optical SETI, also sponsored by the Planetary Society. And in that search, we used the existing 61-inch optical telescope at Harvard, Massachusetts. That's about 40 miles out of town here, which, by the way, is the largest optical telescope east of the Mississippi. We used that telescope in a piggyback sort of parasitic mode, and we basically split off about half the light from their experiment and attached a

detector that we built for the job and looked at the same stars that they were pointed at. That experiment went nicely, went for about five or more years. We published, there's an article in the earlier Planetary Report talking about what we did and didn't find. We also published an article in the Astrophysical Journal, the technical journal of astronomy, astrophysics. Over that period of five or more years, we looked at some 6,000 stellar candidates, that is other suns, in some 20,000 observations. And we found from time to time occasional blips, but non-repeating blips. And it was quite a nice experiment. We had a lot of fun.

Students got to learn lots of things and build new gadgets. It was quite a nice experiment. We had a lot of fun. Students got to learn lots of things and build new gadgets. But the unsatisfying part of that experiment was the sky coverage. Although we looked at these 6,000 stars, we looked in total only about one 100,000th of the sky area. We were really looking through a soda straw, star by star and not much else. star by star and not much else. And so we hatched the plan actually fairly early on during that experiment to see if we could build a new telescope and detector array that could cover a substantial fraction of the sky. And what we built in the end is the new all-sky optical SETI experiment.

We had to build our own telescope. It's a 72-inch. Therefore, it's now the largest telescope east of the Mississippi. And we attached to it a detector array that consists of 1,000, actually 1,024 very rapidly capable individual detectors. Each of them can detect and record the light brightness every billionth of a second. So we have 1,000 detectors doing a billion measurements per second each. That's a trillion measurements per second, which we like to say is the equivalent, at least in quantity, of all books in print every second. All books in print are probably somewhat more interesting than what comes out of this experiment. But that's what we've got. And we use it in what's called a meridian transit mode. It points up and we don't move the telescope each night. We let the

Earth do the heavy lifting and the sky passes through this stripe, this north-south stripe of sky. And each night we move it to a different north-south orientation, declination, so-called. And over the period of about a year or somewhat more than a year, we've covered the entire sky. In fact, now we've covered the entire sky two or three times. Those detectors and the electronics behind them that really, I think, are great examples of the innovation that you've brought to this project. Looking at a thousand detectors at a billion times per second took some new electronics that didn't exist at the time. times per second, took some new electronics that didn't exist at the time. And my graduate student at the time, he's now a postdoc working on the same planet finding kind of stuff now at Berkeley, student at the time, Andrew Howard, actually designed the chip, the chips that are used for this. He calls it PulseNet. We had 32 of these things built. They each process 3% of that data.

So the whole array covers all that data. So we had to do that. We had to build the camera, put these detectors in, all the computer stuff that goes behind it. It was quite a project and took several people a number of years to get it working. Yeah, I'll have to tell Andrew Howard that I say hi. I think he accompanied you the last time that you appeared on this radio show, last time we heard from you. the last time that you appeared on this radio show, last time we heard from you. You're looking for laser flashes. How bright, how sophisticated a laser would E.T. have to have for you to be able to detect it?

And I know that depends to a large degree on how far away he is. Yeah, that's a good question. Well, certainly something more powerful than the kind of laser pointer you use when you're giving a talk. But not more powerful than what we can build on Earth now. The most powerful lasers that have been built can put out a petawatt. That's 10 to the 15th watts. That's more power than all the electrical power on Earth by about a factor of a thousand. Such a laser attached to existing telescopes, like let's say one of the Keck twins used in reverse mode as a beam director, would make a flash of light which during the time of the flash and in the narrow beam that it makes would be seen from far away to be much brighter

than the light coming from our star at the same time. That is, it would look about 1,000 or 10,000 times brighter than starlight. It would be unmistakable to a civilization that we were aiming it at if they happened to be looking in our direction during the time of the flash, and if they had the kind of equipment that we're using now to look for signals of this sort. And I should emphasize that we do not transmit signals. We are only looking for them. The transmitting end of the business is much more difficult, much more expensive, and much more boring. It takes a round trip of at least a few centuries, unless these ET are really close, before you get an answer.

And it's hard to get a graduate student or even a postdoc to sign on to that kind of experiment. That's Paul Horowitz, head of the SETI Research Group at Harvard. We'll continue our conversation about the optical SETI search in a minute. This is Planetary Radio. Hey, hey, Bill Nye the Science Guy here. I hope you're enjoying Planetary Radio. We put a lot of work into this show and all our other great Planetary Society projects. I've been a member since the disco era.

Now I'm the Society's Vice President. And you may well ask, why do we go to all this trouble? Simple. We believe in the PB&J, the passion, beauty, and joy of space exploration. You probably do too, or you wouldn't be listening. Of course, you can do more than just listen. You can become part of the action, helping us fly solar sails, discover new planets, and search for extraterrestrial intelligence and life elsewhere in the universe. Here's how to find out more. You can learn more about the Planetary Society at our website, planetary.org slash radio, or by calling 1-800-9-WORLDS.

Planetary Radio listeners who aren't yet members can join and receive a Planetary Radio t-shirt. Members receive the internationally acclaimed Planetary Report magazine. That's planetary.org slash radio. The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan. My guest is Paul Horowitz, professor of physics and electrical engineering at Harvard, where he also heads the SETI Research Group, which includes the All-Sky Optical Search for Extraterrestrial Intelligence,

searching for the brilliant flash of laser light that will tell us we are not the only smarties in the galaxy. If these flashes are being sent our way, why aren't they being detected by instruments like the Keck? Yeah, great question. The kind of astronomy that people do when they're not doing optical SETI is not sensitive to this kind of a signal. When you do spectroscopy, you typically integrate for many seconds or minutes or sometimes even hours. Or if you're doing imaging, you

basically integrate up the light and make an image. You're not sensitive to light on the time scale of a billionth of a second, except insofar as it adds to the total accumulated light. And a short, bright flash of light like this, on the average, does not look like anything. So you won't see it with a telescope like Keck, unless you attach detectors to the Keck that are sensitive to this extremely short flash of light. And that's sort of one of two reasons. The other is the kind of astronomy that people do with telescopes like Keck is not looking at the whole sky, looking at star after star. It's typically picking an interesting kind of object. Maybe you're looking at quasars or maybe you're looking at nebulae or maybe you're looking at particular variable stars or whatever and concentrating on that.

So the amount of the sky that you actually cover in that kind of astronomy is minuscule. And again, that's part of the reason for the all-sky, is to try to get comprehensive on the sky, as well as to become sensitive to these extremely short flashes of light. This thing is tuned up for this job, and conventional astronomy, even with the most expensive and large telescopes, is not. So Paul, let's say that E.T. is trying his best to say hello to us. How do you tell his flash from anything else which would have to be considered a false positive? Yeah, well, you know, there are other flashes of light. For instance, gamma rays or cosmic rays coming into the Earth's atmosphere do make brief flashes of light.

And we see these things. We insist that a signal look correct, that is come from a single point in the sky, not a streak, which is what you get from these gamma events. And that it be repeatable, that when we look again at that star, or if we follow it with a tracking telescope, that we're able to see a sequence or some unmistakable and artificial type signaling, as opposed to just an occasional once-only flash of light. If we were to find something like that, and I should add that when we see an interesting and compact event

that looks at least like a good candidate, it's immediately added to our please-look-at-me-again target list and is observed as often as we can for the next some period of time until we've pretty much eliminated it. But if we were to find something that gave us a couple such flashes coming from apparently the same place in the sky, we would immediately invite some other observatories to look for the same thing. You could never consider this a true detection until it's seen by at least some remote and independent observatory. And, you know, your listeners have probably read Carl Sagan's novel Contact or seen the movie.

What happens when they find this signal and it seems to be coming from out there? They immediately call their colleagues down under in Australia and have them pick up the same thing. And it would be that way in this business, too. And we don't need a protocol to tell us that that's the thing to do. We know in our bones as scientists that this is what's required. Once it's observed in several places that it's unmistakably artificial, then we've probably got a detection. Although one always wants to be a bit cautious, the little green men that were found by Ryle's group in England

turned out to be pulsars, not little green men. Not a bad discovery though, but to quote Carl Sagan, extraordinary claims require extraordinary evidence. Right, exactly. Yes, I don't think you want to just go calling up your favorite reporters because something interesting happened the night before. We're almost out of time. You have been nothing if not innovative in this project, and it continues to evolve and improve. What's in store?

Let me just say on the innovation that it's largely due to the students here. Just brilliant, wonderful. And I'll tell you, several such things that are going on right now. One of my students, current students now, Curtis Mead, has come up with a really clever way of using very high speed, basically using Moore's law, this incredible improvement of capability, to make our experiment 16 times as comprehensive so that all the pixels can be recorded when an event comes. Right now, we can only record one-sixteenth of them because of limitations in that special chip that Andrew designed. of them because of limitations in that special chip that Andrew designed. Another thing we'd like to do is get a second independent telescope working nearby so we can follow up each of these little events, perhaps using our leftover detector from our earlier targeted search. A third possibility is to use the optical gamma detectors at Mount Hopkins. We've already started doing some work with that, and it's reported in this article.

And lastly, we're working on techniques to improve our calibration and pointing accuracy so that when, if and when we find something that's really interesting, we can really narrow it down to a tiny location in the sky. Paul, thanks again for joining us, and good hunting, and don't lose the phone number. Thanks very much, Matt. Paul Horowitz is professor of physics and electrical engineering at Harvard University. In fact, he wrote the book on electrical engineering. Look it up. He also heads the SETI research group at Harvard, which, among other things, operates the all-sky optical SETI search that we've been talking about over the last few minutes.

Give us another minute or two, and we'll be talking with Bruce Betts in this week's edition of What's Up. That's right after we get this Q&A from Emily. Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, how come we have orbiters at Mars that can spot the rovers on the surface, but there hasn't yet been a lunar orbiter that is capable of photographing the Apollo hardware? There have been two orbiters at Mars with sharp enough eyes to see landers on the surface, Mars Global Surveyor and Mars Reconnaissance Orbiter. But we've never sent a spacecraft to the moon that's capable of spotting any of the dozens of pieces of landed hardware from space. Why not?

capable of spotting any of the dozens of pieces of landed hardware from space. Why not? Well, we don't just send orbiters into space in order to get vanity shots of other spacecraft. For Mars, the sharp-eyed cameras are part of a very long-term program of Mars science. Mars fascinates us because it has the most Earth-like surface of any place in the solar system, with evidence for past liquid water. Liquid water may even have occurred there very recently, geologically speaking. Studying Mars is about studying life, searching for micro-environments where it may once have survived and where future explorers may populate the planet.

We need those high-res cameras to study all these active geologic processes. By contrast, the Moon is geologically dead, and its surface has been softened by billions of years of impact erosion. The resolution of Mars Reconnaissance Orbiter or even Mars Orbiter Camera just hasn't been necessary to further lunar science. That's not to say we won't ever spot

the Apollo landers on the Moon. In fact, later this year, NASA plans to launch Lunar Reconnaissance Orbiter, whose purpose will be to map at very high resolution possible future landing sites for a renewed human exploration program. While it's up there, there's no doubt it'll be taking those vanity photos of the relics of past successes and failures. Got a question about the universe? Send it to us at planetaryradio at planetary.org. And now here's Matt with more Planetary Radio.

Time again for What's Up on Planetary Radio. We are with the Director of Projects for the Planetary Society, Dr. Bruce Betts, in the parking lot outside Planetary Society headquarters because we are about to conduct the latest project that the Society actually doesn't know it's behind. Yes, indeed, you found yet another way to have people look at us really funny when we are in an odd place out here in the parking lot. At least it's beautiful outside. Yeah, it is a really pretty day here under the nice blue skies, and we're here to see if we can break a window or two with my new set of stomp rockets.

You know, it's been years since the old kit, the base, got broken, and I finally found a new kit, and so we're going to see if we can break a window or two. Yes, a long tradition that you've had, bringing them to planet fests and other strange places. Nothing like seeing stomp rockets go off across the big exhibit hall at the Pasadena Convention Center. We had celebrity stomp rocket people there. It was a lot of fun. Oh, good times, good memories. Well, let's talk about what people can see in the night sky. You can check out Venus looking extremely bright, about as high as it ever gets in the evening sky.

Check it out after sunset in the west. It's the really, really bright star-like object. And then rising in the middle of the night is Saturn over there in the east, and it's high overhead in the middle of the night. For those of you in certain parts of the world, there is an annular solar eclipse occurring January 26th. You can check that out if you're floating through the Indian Ocean in certain parts of the world, there is an annular solar eclipse occurring January 26th. You can check that out if you're floating through the Indian Ocean in certain places or hanging out on certain parts of Sumatra or Borneo. But you can also check out a partial eclipse visible throughout most of southern Africa, southeastern Asia, and western Australia.

What is an annular eclipse, you ask? Well, we'll check back with you on that in just a moment. On to this week in space history. 40-year anniversary What is an annular eclipse, you ask? Well, we'll check back with you on that in just a moment. Ah. Ah. On to this week in space history. 40-year anniversary of the first docking of two manned spacecraft. Soyuz 4, Soyuz 5. This is a genuine docking. They didn't just rendezvous. They actually hooked up.

They hooked up, yeah. Yeah, anyway, moving on to random space facts. Now you're really embarrassed. There's a guy right over there. So anyway, hey, there are four types of solar eclipses. Did you know that? I didn't know that. I should tell the guy you're a professional. John, Paul, George, and Ringo.

No. A total eclipse, of course, when the sun is completely blocked out by the moon, the really spectacular ones. We've got an annular eclipse like the one happening here where the Sun and Moon are lined up, but the apparent size of the Moon is actually smaller than that of the Sun. So you see a disk, a little ring of the annulus of the Sun around the Moon. A hybrid eclipse is a really freaky, rare thing. It's intermediate between a total and annular.

So some parts of the Earth see total. A hybrid eclipse is a really freaky, rare thing. It's intermediate between a total and annular. So some parts of the Earth see total. Some see annular, depending on where you are on the Earth, being how far you are from the moon. And, of course, the regular old partial eclipse where things aren't quite lined up and part of the chunk gets taken out. Never heard of the hybrid. That's what I'm here for. Freaky. Freaky, my friend, that we happen to live in times where the moon is just the right distance in size and we're the right distance from the sun to deuce that blocking out of the sun. And it's mostly the elliptical nature of the moon's orbit that causes these variations

between these four types of eclipses and when we see it. Let's move on to the trivia contest. We asked you, who is the only person to ever discover all the moons of a planet? How'd we do? You know, we had a huge response. Not quite a record, but way up there because people really wanted to go for this one. And I'm just going to give you the winner right up front. It was Daniel Salkin.

Daniel Salkin of Forest Hills, New York. I think he's a first-time winner, who said it was Asaph Hall in 1877. It was indeed Asaph Hall, quite the guy. Quite a lot of effort to try to find him, finding Phobos and Deimos. He also did other spiffy things, as Craig Jernay pointed out to us. He determined the orbits of satellites of other planets, double stars, rotation of Saturn, mass of Mars. And according to Kirby Runyon, he even devised a method of computing pi. I guess he worked very closely with his wife, Stickney. You know that story.

Yes, yes, he did. And in fact, the largest crater on Phobos that almost was big enough to break it apart was named after his wife. It's Stickney Crater. But I'm sure you have more to tell us. We have a listener who will go unnamed because I don't know if he's still paying alimony or not, who says that he would love to have the opportunity to name a cataclysmic event after his ex. Well, okay. And with that, shall we go on to our next trivia contest? Yeah, go ahead.

All right, this one's a little tricky to phrase. We're back to solar eclipse land. You've got different parts of a shadow. You've got the oombra. Now, hang on. I don't want to be run over by this pickup truck. Okay, I think we're all right. I hired them.

That's the whole point. I want it on the show. You just do not want me to own stomp rockets, do you? No, I do not. Okay, so anyway, we've got different kinds of parts of a shadow. You've got the umbra, where if you're looking at the object like the sun in a solar eclipse, it's totally blocked out by the object in the foreground, the moon. You've got the penumbra, where you're in the part of the shadow where part of the sun is blocked out,

a little side of it, like in a partial eclipse. But what do you call the region of an eclipse shadow from which the occulting body appears entirely contained within the disk of the light source? What are you in when you're observing an annular solar eclipse? Go to planetary.org slash radio, find out how to enter. I'm trying to decide how I'm going to reduce that to one sentence on the website. But, all right, some people are going to love you for this. Some people are going to hate you for this one.

But whoever you are, you've got to get your answer in to us by Monday, the 19th of January at 2 p.m. And what prizes are we awarding? We will continue to award a desk calendar, This Week in Space. Really cool. Has lots of good This Week in Space history. Pretty pictures. Wonderful articles. And you can find out more how to acquire your own from a link at planetary.org slash radio. And try to compete for a free one in this contest.

And a rewards card from Oceanside Photo and Telescope at opcorp.com. We're going to get you one of those as well. Before we do the rocket, I've got to say this. Somehow, we missed one of the mnemonics for star classifications, stellar classifications. Horrors. Yes. Our friend Kevin Hecht asked, did we miss it? And so, yes, I said we did. And he wrote this beautiful thing as like a resolution

by the Illinois State Legislature, the General Assembly, which we don't have time to read. But I love the resulting mnemonic, which is Obama, OBA. Obama favors getting kids to Mars. Is that part of the new mandatory preschool program or is that something else? And I don't know if that means his kids or anybody's kids. I hope it means all our kids, actually. And I don't know if that means his kids or anybody's kids. I hope it means all our kids, actually. Whereas we forgot to do that before, be it resolved that you did it now.

So there you go, Kevin. There's your honorable mention. Okay. You are the honorable launcher today, I think. I'll just be the range safety officer, okay? All right. Okay. We're ready.

Let's do it. Okay. Here we go. We're all set up in the parking lot. I'm going to put the microphone down there in a moment. He's about to stop. Now, of course, what we have is a little air bladder connected by a hose to the cheap yellow plastic stand upon which is mounted the rocket. Any comments before this mission?

Has a lovely red foam nose cone. Lovely fairing on that rocket you've got there. I'm ready. Let's do it. Give me the countdown. Here we go. We're going to start with five, four, three, two, one. Oh, great sound. Oh, and it just came right down on that BMW. BMW didn't it? All right, everybody. Oh, we're going to get out of here of here go out there look up in the night sky and think about things that might hit your car when crazy radio people go out and do crazy things thank you and good night he's bruce betts the director of projects for the planetary society

he doesn't carry nearly enough personal liability insurance he joins us every week here for What's Up. Join us next time for a fifth anniversary celebration of Spirit and Opportunity, the Mars Exploration Rovers. Planetary Radio is produced by the Planetary Society in Pasadena, California. Have a great week. Редактор субтитров А.Семкин Корректор А.Егорова