Planetary Radio: Space Exploration, Astronomy and Science - SETI@home Aims Arecibo at the Best ET Candidates

Episode Date: March 17, 2003

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This is Planetary Radio. If E.T. phoned home, could we eavesdrop on the conversation? It's just possible that we already have. Of course, we're talking about the search for extraterrestrial intelligence. This week, Dan Wertheimer of SETI at Home will have the unprecedented opportunity to revisit some of the most promising possible sources of radio signals from beyond our solar system. possible sources of radio signals from beyond our solar system. He talked with us just before beginning his trip to Puerto Rico and the great Iracebo dish. Emily Lottwala will answer a listener's question about just how far out into the universe we can hear

and how far we can be heard. And later, Bruce Betts will dish up another installment of What's Up, including, yes, another trivia contest. By the way, don't forget our special guest on next week's show, Sir Arthur C. Clarke. Now, from somewhat less than a light-year away, here's Emily's message. Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, would a civilization two million light years away be able to detect us? After all, they would see Earth as it was 2 million years ago before we were here.

And isn't it also possible that by scanning too far, we could detect a civilization that is no longer there? We gave this question to the Planetary Society's SETI coordinator, Tom McDonough. It's quite true that a civilization 2 million light years away would not be able to detect our civilization. 2 million years ago was before the pyramids, before agriculture, even before Homo sapiens. In fact, human-produced signals can only be detected

within a distance of around 100 light years, the span of time that we have been producing radio and television signals. The Earth is not easy to detect yet. How about those other civilizations? Stay tuned to Planetary Radio to find out. Dan Wertheimer, project scientist, chief project scientist for the SETI at Home project. Are you getting on a plane tomorrow? That's right. We're going to the world's largest radio telescope to hunt for ET tomorrow.

And, of course, I suspect all of our listeners, and certainly all of us at the Society, wish you the best of luck. This trip has been a long time coming, hasn't it? Well, this is the culmination of four years of work by actually four million people around the world, and 226 countries have been helping us analyze the data from the Arecibo radio telescope. And combined, they make the largest supercomputer on the planet.

So there's a huge amount of computing that's been done, a data analysis, and now we're following up on that, looking at the very best signals that we've found over the last four years. You might say that I think you could definitely make the argument that you have more investigation partners than any scientific inquiry, probably in history. Yeah, that's going to be a long when you write a scientific paper

you list all your collaborators, the co-authors. It would take thousands or perhaps millions of pages to list all the people that have helped us. Well, of course, if you are successful in this effort coming up out of SIBO, it might just be worthwhile listening to all those folks because of the significance of that discovery. Tell us about what you're going to do there as you basically

take a second look. As you know, we're searching for radio signals from other civilizations, and the concept is that Earthlings are sending off radio and television radar all the time. In fact, you should be careful what you say on planetary radar, radio, because those signals go out into space through the atmosphere, traveling at the speed of light. And early radio broadcasts have reached a few thousand stars. I love Lucy and Sullivan.

And so maybe ET has got some kind of technology like radio or radar, and that's the kind of signal that we're looking for. And to do that, you need a huge antenna, and we use the world's largest, the Arecibo radio telescope in Puerto Rico. It's 1,000 feet across. It holds a billion bowls of cornflakes. And we've been collecting data there continuously for the last four years and sending it out to the SETI at Home volunteers for analysis.

They're running the SETI at Home screensaver program. And those volunteers who are running that program, everybody analyzes a different part of the sky, and they've been finding the strong signals. And we've made a list of the most interesting signals, the ones that repeat, the ones that are near planetary systems that we know about. And those are the ones that we're going to go check on next week. That's one of the things that I was most curious about, that you hope to look at maybe 100 to 200 of these best candidates.

Can you talk a little bit more about what helped these make the cut? When a city home volunteer analyzes their piece of sky, their work unit that they've been assigned, they send back a strong signal. They go through their data looking for the most interesting things at different frequencies, at pulse periods. They go through billions of possible signal types. The interesting things that they find are sent into our database here in Berkeley, and then we have to cull through that and see, was it really interesting

or was it a satellite broadcast, was it a television broadcast, did they find a terrestrial signal versus an extraterrestrial signal? The ones that really get our attention, the ones that we're the most excited about, are the repeaters. Every six months or so, the telescope will go back to the same place in the sky. And if we see the same kind of signal at the same place in the sky at the same frequency a second time or even a third time, that's what really gets our attention, these things that repeat.

And, of course, the more they repeat or the stronger the signal is, the least likely it is to be a noise event, a little glitch in the receiver. And so those we follow up on. There are different kinds of signals that we're interested in. There are the things we call gaussians. As the telescope approaches a star, the signal gets stronger and stronger, and then as we move away, it gets weaker and weaker. If it traces out that characteristic curve, a bell-shaped, Gaussian-shaped curve,

that gets us interested. A pulse that's repeating, bip, bip, bip, bip, bip, is interesting. A signal that's drifting in frequency instead of just staying constant like E, but changing in frequency, you know, that kind of thing we follow up on. And so these 100 to 200 that you might get to have a second, not just really a look, but a listen to, they all share some portion of those criteria. That's right. And the computer has been going through the billions of signals that have been returned to us from the SETI home participants. And it makes the first cut. It decides what's interference. It decides what's

strong, what's repeating, what's coincident with a star. If it has planets going around it, that gets a good grade. Anyway, the computer scores all this stuff. But in the end, there are a bunch of humans that have to, there are five humans here in Berkeley that make the ultimate decision about what we can look at. The telescope time is very precious. It's $1,000 an hour. And so we look very carefully and we argue amongst ourselves about what we can look at. The telescope time is very precious. It's $1,000 an hour. And so we look very carefully, and we argue amongst ourselves about what we're going to look at. Are you mostly limited by the amount of time that you can have on this instrument, the great dish at Arecibo,

which is, of course, in great demand for many things, many projects that radio astronomers want to do? That's right. It's a precious time. And the way it works is that if you're an astronomer and you want to use that telescope, you'll be lucky to get the world's biggest telescope a day or two a year to do your research. And we've actually figured out a way. Normally when we collect the data, we use the telescope year-round, 24 hours a day.

We call it commensal SETI or piggyback SETI. We've got our own receiver that can collect data independent of what the main astronomer or researchers are doing, and we can collect data at the same time. So we've got the world's biggest telescope year-round. The disadvantage with that commensal or piggyback technique is that we don't get to point the telescope, but we don't know where to look anyway normally. That's true. It just is that you're not calling the shots,

but to have this opportunity to be on that dish that is so much larger than anything else, nothing else really comes close, I guess. Piggyback is not so bad. Yeah, but this time, next week, we need to point the telescope. We know exactly where to look. We found the 150 things that we want to point the telescope to, and now we need dedicated time. And so the way that works is you write a proposal to the National Science

Foundation, the Arecibo Telescope people. It's reviewed by peers. If they think that it has good, worthy scientific merit, you'll get some time on the telescope. How long will you actually be able to focus on any one source before you need to move on? We'll just spend a couple of minutes at each source because we want to observe so many. But in two minutes with a very good receiver, it's even better than the one that we normally use, we'll be able to have even better sensitivity than we normally do when we scan the skies, when we use this piggyback commensal technique. when we scan the skies, when we use this piggyback commensal technique.

So even if the signal is weaker than we normally see it, we will have a good chance of detecting it again. We've got about a minute before we need to take a break, and I want to talk much more after that break about what will happen with all of this new data that you're going to get. But does this mean, after this great observation opportunity that there's going to be a lot more data for all of us out here with SETI at home on our PCs? Well, this is not going to create a huge amount of data to analyze. You know, we're only taking data for a day.

We've been collecting data for four years from the Arecibo telescope. But we have plans to expand the search to look at new frequency bands. We hope, if we can raise the money, to go to Australia to cover the southern parts of the sky. So we hope to collect a lot more data and continue to involve the 4 million volunteers and expand the SETI capabilities. We're talking with Dan Wertheimer, who is the chief scientist for the SETI at Home project, virtually on the eve of his departure for Puerto Rico and the Great Dish at Arecibo. We're going to continue this conversation right after this break, and I would like,

Dan, if we can, to talk about what will happen, what is the contingency plan in case you get a wow signal, and we'll have to talk about what that means as well when Planetary Radio continues in just a moment. This is Buzz Aldrin. When I walked on the moon, I knew it was just the beginning of humankind's great adventure in the solar system. That's why I'm a member of the Planetary Society, the world's largest space interest group. The Planetary Society is helping to explore Mars. We're tracking near-Earth asteroids and comets. We sponsor the search for life on other worlds, and we're building the first-ever solar sail. We sponsor the search for life on other worlds, and we're building the first ever solar sail.

You can learn about these adventures and exciting new discoveries from space exploration in the Planetary Report. The Planetary Report is the Society's full-color magazine. It's just one of many member benefits. You can learn more by calling 1-877-PLANETS. That's toll-free, 1-877-752-6387. And you can catch up on space exploration news and developments at our exciting and informative website planetarysociety.org

The Planetary Society Exploring New Worlds Dan Wertheimer is off to Puerto Rico tomorrow in search of E.T. Not in Puerto Rico, of course, but up in the stars, where he will have a full day to point the great dish at Arecibo pretty much wherever he wants as chief scientist of the SETI at Home project. And he knows pretty much where he wants to point it.

Dan, once again, thanks for joining us on Planetary Radio. Pleased to be with you. Let's follow up a little bit on what happens if you find something, reexamining one of these sources that you've looked at previously, and you start to think, my goodness, it looks like somebody's out there. First of all, would it just be noted, as was the famous wow signal some years back, just somebody making a little note on a plot on a piece of paper, what would probably happen?

And would you know, as you're sitting there next to the dish, if you had something that was a really strong candidate? We are going to be analyzing the data at the telescope in near real time. We're going to be checking it out as we go along, watching the screens. The computers will alert us to strong signals at different frequencies. If we find something that's really interesting, we'll stop what we're doing. We won't go on to the next candidate radio signal. We'll re-examine it. We'll move the telescope on to the source. We'll move it away

to see if it goes away, back and forth. If it's really exciting, we will call up another observatory, another telescope, to ask if they can see the signal, too. We need some independent confirmation here, because it might be a bug in our software. A graduate student turned to play a prank on us. So you want to get an independent group, different people, different telescope, different instrumentation, to see if they can see this thing as well. And if you have two different telescopes widely separated in different countries, you can kind of triangulate on it. You can measure the distance and make sure it's not something in our own solar system,

not an interstellar probe or a satellite or something like that. And then we'll know that it's really interesting. And once we have independent confirmation, then we can make an announcement to all the world. And all that information will be shared, the coordinates, the frequencies, everything we know about the signal. And I imagine a lot of people start looking at it, different telescopes in different places. And let's make it real clear that it's not like the CIA has got a representative sitting next to you at the dish,

ready to swoop in and place a top secret on any real results? No, this is a project for all of humanity, the whole Earth. It's international. The data is sent out around the world. And this is not government-funded research. The government cut off the funds for SETI 10 years ago. This is largely funded by the Planetary Society, who got the whole project, the SETI

at Home project, started in the early days. And the Planetary Society is behind this, but it's for all mankind. Before we move on, we better explain to the probably few people in our audience who've not heard of it what that wow signal was. There have been occasionally strong signals that SETI researchers have found in their research. One of the more famous ones was found

a long time ago in the early days of SETI at Ohio State University. It had a big telescope. It was a very strong signal. It looked just like the kind of signal that you'd expect from ET. It had the right characteristics. The reason it's called the WOW signal is when the researchers saw this thing, a guy wrote WOW with an exclamation mark on the data.

And since then it's been followed up on by many, many people staring at it by all kinds of telescopes with much more sensitivity than they had in the old days. And nobody's ever been able to confirm that signal. It's never been seen again. I think it's actually the least likely place for ET to be lurking because it's been followed up on so many times and nobody's seen it. Almost surely it was some radio interference. But occasionally you do find these things. There's a big problem with radio interference. The radio skies are getting more and more polluted by humans setting up transmitters. Some bands are almost impossible to work in that we'll never be able to search for ET unless we go off into space where we can be shielded from all the

terrestrial activities. It's a terribly unscientific question to ask you, but you must daydream or dream about being the first to find that signal coming from an intelligence beyond our solar system. Of course, it would be a tremendous discovery. It would be the discovery of millennium. People have been thinking about this question, are we alone? Is anybody out there for thousands of years? And it would be great to be the group that finds it. But actually, I'm not optimistic about what's going to happen next week.

I don't think our chances are very high even though it is the culmination of four years of work and I'm very proud of the world's largest supercomputer, all the volunteers that have helped us and the most sensitive comprehensive search that we've been able to do. But I don't think it's going to happen next week. I think I'm optimistic in the long run. I think earthlings are a fairly primitive society right now. We're just getting in the game.

We've only had radio 100 years. We can't do the thorough comprehensive searches, looking at all possible frequency bands at all. And it would be easy to miss the radio signals right now. But the reason I'm optimistic in the long run is because the technology is changing so fast, doubling every year. We used to listen to 100 channels. Now we listen to more than 100 million channels.

So even though I think right now we're just learning how to do this, I think it will probably happen in our lifetimes. And we had a conversation on the show just a couple of weeks ago about SETI branching out in other directions to other bandwidths, including optical SETI. And so the search continues. You guys at SETI at home, whatever happens with the core of this, creation of this distributed computing model, this world's largest supercomputer that relies on millions of personal computers in homes and offices across the world. And this model is one we talked about with your colleague, David Anderson, back in December.

He is, of course, the director of the SETI at Home project. And I guess now, as other research groups have discovered how powerful a technique this can be, you guys are leading an effort to sort of standardize how these projects can do this kind of distributed processing? That's right. We are trying to make it easy for other scientists to use distributed computing to do their research. Instead of doing SETI, people are now doing research looking for drugs. They're analyzing proteins. And there are a lot of people that would like to harness these volunteers

around the world to do big supercomputing projects. Normally it's very expensive to get computer time if you need really a lot of computing time. And SETI at Home is actually the biggest supercomputer on the planet. If you add up all the volunteers, they donate 1,000 years of computing time every day. They've donated a million years of computing time so far. It's bigger than any supercomputer on the planet, even if you add up all the supercomputers, the big supercomputers around this world. So for other researchers to do this kind of project,

for whatever kind of research that they want to do, whether it be SETI or something in astronomy, chemistry, biology, there's a global warming climate modeling project at Oxford. We're trying to make an infrastructure to make it easy, so you don't have to be a computer science expert in distributed computing like David Anderson, to make it easy for them to do that. And we're building an infrastructure. It's open source, like free source code that anybody can download

and try to make it easy for them to run their own distributed computing projects. Dan, we've only got about a minute left. Last question to you. What's it like there at Arecibo? I mean, where do you stay? Is it hard to get to? Do you need a Jeep, or is there a freeway going by a quarter of a mile away? It's about a two-hour drive from San Juan, the capital.

It's in the mountains. It's kind of out in the middle of nowhere. It's rainforest kind of country, very tropical. You hear at night very loud coquille frogs chirping away. It's really beautiful. It's a wonderful place, a very exciting place to be, a lot of interesting people around there. And so I'm really looking forward to being there and hoping we can find E.T. Well, we will wish you a wonderful trip and even more so a great success

in this re-examination of these possible places where who knows, maybe somebody may be looking back at us and trying to communicate. We've been talking with Dan Wertheimer, the chief project scientist for the SETI at Home project, and anyone who wants to learn more about SETI at Home, including how they can participate, I suppose they can visit the Planetary Society website, right, Dan? Yeah, if you want to help us analyze the signals from the telescope, if you want to help us hunt for ET or just learn about the project, the website to go is planetary.org.

Dan, thanks very much. Bon voyage and happy hunting. Thank you. Planetary Radio will continue in just a minute. I'm Emily Lakdawalla, back with Q&A. If the SETI project detects a civilization 2 million light years away, that civilization may well have died out during the time it took for its signals to reach us. Still, even if we detect a dying or dead civilization, it could have a lot to tell us. Maybe we could even learn from its mistakes.

Actually, though, even if such a civilization once existed, we're not likely to detect it. Most SETI searches focus on our own galaxy, examining radio and optical sources that are typically thousands, not millions, of light-years away. Recent efforts to discover extrasolar planets seem to indicate that planets are common around stars in our neighborhood, so there are probably many thousands of planets within less than a thousand light years. If we pick up a civilization's transmissions within this distance, there is hope that the civilization may still be flourishing. Got a question about the universe? Send it to us at planetaryradioatplanetary.org and you may hear it answered by a leading space scientist or expert. Be sure to provide your name and how to pronounce it, and tell us where you're from.

And now, here's Matt with more Planetary Radio. Bruce Betts is here to tell us what's up and lots of other great stuff. He's even got a new trivia contest question for us. Bruce, welcome back. Thank you very much. I am once again giddy to be here. And on the telephone with limited fidelity, but we'll be back live or in person with you next week. Yes, we will, and it will be much more Fidel.

Yes. Speaking of Fidel, no, I'm sorry, that would be a political show. Go ahead. How are we doing? I do see Cuban dictators walk into a bar. That's not this show. Sorry. Okay, let's go to What's Up in the Sky.

Stay tuned for the April 1st show, everybody. You won't be disappointed. Go ahead, Bruce. What is up in the sky? Planets and stars. Can't you remember a thing, Matt? Oh, shoot. I keep forgetting whenever it's cloudy.

Yeah, I'm sorry. Anyway, we've got Jupiter looking extremely bright in the evening and Venus extremely bright in the early morning. Those are your two primary planet targets this week. Jupiter looking overhead in the mid-evening, somewhere around, say, 8 p.m., and the brightest object up there at that time. And if you want to compare it to the brightest star in the sky, look towards the south and

should be able to see lower down Sirius, the brightest star in the sky. And in the early morning, before dawn and into dawn, you can see Venus in the east-southeast. Something else to look for, which because this show does get an international audience, we can't tell you right where to look, but we can point you places, is to look for satellites, spacecrafts. And a lot of people don't realize that you actually can see things,

particularly the big ones like International Space Station. If you look up at the right time in the right direction, it's quite obvious and looks like a bright star going across the sky. You can also see quite easily some of the other large satellites, at the same time in the right direction, it's quite obvious and looks like a bright star going across the sky. You can also see quite easily some of the other large satellites, such as Hubble Space Telescope. The trick, of course, is where do you look and when? And there are various sites, for example, for International Space Station.

Some places in the world listed on NASA's space flight website, so you can get to that through www.nasa.gov. You can also go to another site, which you can actually see all sorts of spacecraft, of where they will be, depending on where you live, at www.heavensabove, and there's a dash between the two words,.com. Another fun thing you might try is looking that up and figure out when there's a good time to see something in your neighborhood. And usually with the space station, you can see it pretty well fairly frequently for most of the world's population. What do you think of that, Matt? I love it.

Let's give that last URL once again quickly. It was heavens-above.com? Yes. Okay, great. All right. What else do you have for us this week? Great. All right, what else do you have for us this week? This week in space history, March 18, 1965,

Alexei Leonov made the first ever spacewalk for 10 minutes aboard Voskhod 2. Those pesky Soviets, they beat us again. That all ended a few years later, of course, with Apollo 11, but it was a little while later when the first American made it, right? Right. Ed White on Gemini 4 in early June of 1965, two or three months later. Are we marking any other anniversaries? We are.

Speaking of Gemini, March 16, 1966, Gemini 8 was launched. This mission included the first docking of two orbiting spacecraft. A key part of getting to the moon and continuing to be a very important part of human space travel. What do we do now? Do we move on to the trivia question, or I guess we want to give the winner. Not yet. We've got random space facts. How could I forget, especially with that echo? Exactly.

The atmospheric pressure you would experience on the surface of Venus is approximately equal to the pressure you would experience 3,000 feet down in the Earth's ocean, or about one kilometer down. Wow. And that's on a planet that is roughly the same size as Earth. Exactly. Whew, jeez. Nasty place. It's toasty there, too, but we'll come back to that in some other random space fact. Yeah. Okay, now can I give the trivia contest winner? First, let's review the trivia contest.

Question, if that's okay. Oh, God, I can hardly wait, because this is a guy who's been waiting two months to win. All right, well, he's going to have to wait another few seconds. What is the nickname of the relatively large rock a few meters from the Viking Lander 1 spacecraft? And the answer would be Big Joe. And our winner, here it is. Bill, you finally made it. Your ship has come in.

Bill Magnumson. It doesn't look like you'd say it that way, but he did it for us phonetically. Bill Magnumson, Jr. is our winner for this week. He hails from Malden, Massachusetts. And Bill, we're going to send you one of those Carl Sagan Memorial Station T-shirts. Congratulations. Congratulations to Bill.

And for this upcoming week, actually one quick note about Big Joe. It does appear in a lot of the foreground of a lot of the Viking lander one-shots, and it was also one of those things that kind of made people's hearts have palpitations after the landing when they looked and saw Big Joe because it was big enough at about two meters in diameter that if the lander had landed on it, it would have flipped over. So, phew. Yeah. Now, moving on to this week's contest.

Based on volume, how many Earths would fit inside Jupiter? Please round off to the nearest 100. How many Earths would fit inside Jupiter based on volume to the nearest 100? And we will tell you it's more than two. It is at least maybe six, but I'm thinking probably more. We're being somewhat facetious, of course. How will they contact us, Bruce? They will go to planetary.org and follow the links to Planetary Radio, where they will be informed of how to enter. I want to go back to last week's show for one brief moment. Correction, I was stumped by you and was making up words on the spot

because I couldn't remember the right words. It is, of course, ellipsoid, not elliptoid. So you can stop calling and writing now. Thank you very much. We were especially getting nasty notes from the elliptoids, who live on a star about 24 light years away. It's true. It's true, which fortunately or unfortunately, we have those SETI projects that pull those things in.

So anyway, we apologize to the elliptoids and are happy for the ellipsoid people. Bruce, we're out of time. Thank goodness. We'll talk to you again next week. All right, remember, look up in the sky and get happy. Bruce Fetz is the Director of Projects for the Planetary Society. Thank you, good night. You really won't want to miss next week's show.

Why? Because we'll be talking with Arthur C. Clarke. It's not necessary to say anything else, is it? Till then, why not drop us a line at Planetary Radio at planetary.org. And catch up on our past shows at planetary.org. The executive producer of Planetary Radio is Lou Friedman. Charlene Anderson, Monica Lopez, and Jennifer Vaughn provide invaluable assistance. Me, I'm Matt Kaplan. Have a great week. This is the end of the program.