Planetary Radio: Space Exploration, Astronomy and Science - Planetary Radio Looks at SETI

Episode Date: December 9, 2002

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This is Planetary Radio. Hi again, everyone. Thanks for joining us. This week, Planetary Radio goes far beyond our own solar system. This week, Planetary Radio goes far beyond our own solar system. The Planetary Society is a longtime supporter of the search for extraterrestrial intelligence, SETI, a multi-project scientific effort to seek out new civilizations. If you'll pardon our theft of the Starship Enterprises mission statement, lacking warp drive, we can't actually fly around the galaxy making house calls at likely planets, but we can listen and watch for the signs of intelligence reaching across the stars.

Our guest today is David Anderson, a SETI pioneer and head of the SETI at Home project. We'll also find substantial evidence of intelligence when we make one of our regular visits to Bruce Betts for his What's Up segment. But let's get started by learning how SETI really got started, quite possibly long before you thought. I'll be back in just a minute. Hi, I'm Emily Lakdawalla, Science and Technology Coordinator for the Planetary Society, with Random Space Facts. Before the SETI program began listening for signals from outside Earth, humans suggested broadcasting signals

in the hopes of contacting alien civilizations. Karl Gauss, the German mathematician and astronomer, was one of the first to suggest contacting Martians by planting strips of pine trees in Siberia to enclose a huge right-angled triangle, revealing Earthling intelligence via the universal language of mathematics. Viennese astronomer Joseph von Littrow suggested getting the Martians' attention by digging a 24-mile-wide circular ditch in the Saharan desert, then filling it with water, pouring kerosene on top, and lighting it to

signal Earthlings' presence. Other large flaming ditches carved out in the forms of squares or triangles could also indicate intelligent life on Earth. In 1869, French poet and inventor Charles Crowe suggested sending a signal by constructing a huge mirror to focus sunlight and burn out simple numbers on Martian desert sands. In 1924, astronomy professor Davis Todd of Amherst College proposed broadcasting radio signals to the Martians from a dirigible operating 3,000 meters above the ground. Todd even convinced the U.S. government to turn off its radio transmitters for five minutes every hour for two days

so that he could tape record incoming signals, but no extraterrestrial signals were received. I'll be back with another random space fact in a few minutes. Now, back to Planetary Radio. It can probably be safely said that Dr. David Anderson runs the world's largest computer. He is on the phone with us now. David Anderson, thanks for joining us on Planetary Radio. Great to be here. You are a project director of something called SETI at

Home, which is something the Planetary Society has been involved with right from the start. There are certainly some people out there listening to this who already know what SETI at Home is, because as I understand it, you recently have passed 4 million users who participate in the project? That's correct. That is an incredible number, and it continues to grow pretty rapidly, doesn't it? Yeah, we're getting about 2,000 new users per day. Tell us about SETI at Home for those few out there who may not have heard of it. What was the goal that you set out to accomplish?

Well, we're an example of what's called radio SETI, which is an approach to finding evidence of intelligent life outside of the solar system based on radio waves. In the same way that humans produce radio waves in the form of TV and radio station signals and radar and things like that. And these radio waves are able to go through space and actually pass through clouds of dust in space and potentially reach other stars. The same thing could work the other way around. If there are other forms of life in our galaxy and they develop technology and use radio for communication, there's a chance that we could hear radio signals coming from their planet.

As of right now, that's probably the most promising way that we have of trying to detect life outside of Earth. So people have been doing this radio SETI activity since about 1960. A guy named Frank Drake ran the first project based at West Bank, rather, in West Virginia. SETI at home is a particular way of doing radio SETI. It turns out that one of the hard parts about radio SETI is that to analyze the data, sift through these radio waves in digital form and look for these very faint narrow band signals. It turns out that narrow bandwidth, you know, having all the energy at one frequency

is typical of synthetic radio waves but not natural ones. So essentially what we're doing is listening for narrow bandwidth signals coming from other stars. It turns out this is a very computationally intensive activity. Actually the more computing power you can throw at it, the better job you can do with the fainter signals you can hear. We're taking it to an extreme and basically trying to use every computer on Earth to form the biggest possible supercomputer.

And that's where the four million users come into play. We use the computing power of volunteer PCs typically in the screensaver mode, so only when your computer is idle does it get used for our work. And we use the Internet to distribute data to people's home computers and to collect the results. And how long have you been at this? We started the project in 1995 and had about a three-year period of just trying to get a sponsor for it. At that point, the federal government had a policy of not funding SETI research, so we couldn't

ask DARPA or NSF for money. Eventually, we got an initial sponsorship from the Planetary Society, and also from Paramount Pictures through the Planetary Society. And that let us get the project off the ground in 1998, and we went public in 1999 with our screensaver, and we've been operating continuously since then. So that's not a long time to find yourself with 4 million people who have downloaded the SETI at Home screensaver, which does function just as any screensaver does, but at the same time, when somebody is not word processing or chatting

or doing email or whatever, it is actually processing this data. Yeah, and I think there's a lot of keys to the rapid expansion of our user base. One of them is that the screensaver actually shows you in graphical form what it's doing with the data. There are these 3D-looking plots, and if there were a signal, then there'd be kind of a ridge along this surface, and it

shows you the curve fitting that it's doing. It's very fascinating to look at, and there's what we call a viral marketing effect when one person in an office or a school runs their screensaver, other people walk by and they see this strange-looking thing and they start talking about it and learning that there's actually some scientific activity behind it.

Soon we have a dozen or 50 people in that building using the screensaver. And in fact, sometimes those people have banded together, actually a lot of these people have banded together, and have teams that compete. Yeah. In trying to figure out why people like to run SETI at home, it turns out that there's a lot of our users who are really not all that interested in SETI,

but they're more interested in having the fastest computer on the block and being able to prove it by showing up in our leaderboards. Our website has breakdowns of how much work different people's computers have done, and it's broken down by nationality, so you can look at the top SETI at home users in Estonia or Antarctica, whatever you want. At some point, we introduced this concept of teams so you can band together with your buddies. And there's wild competition among the teams. People go to great lengths to recruit new members for their teams so that they can move up in the leaderboards.

We didn't really anticipate that this would be such a strong motivating factor, but all computing power is good for us. We're talking with Dr. David Anderson. He's up at his office in Berkeley. He is the project director for SETI at Home, which now has, as we've said a couple of times, 4 million people who have basically donated computer time to look for signals in this

search for extraterrestrial intelligence. David, where is the data coming from? Currently, we're recording data at the radio observatory at Arecibo. It's in Puerto Rico. It's the world's largest radio telescope, about 1,000 feet across. And if you saw the movie Contact with Jodie Foster, it's the second of the radio telescopes that she uses. It was also in a James Bond movie.

It filled up with water in that one. Golden Eye or something like that. It's the largest and the most sensitive radio telescope on Earth right now. It does have the limitation that it's only able to see sky in the northern hemisphere that is above the celestial equator. So it can see about a third of the sky. One of the things that we're doing right now is planning a new project that will use an observatory in Australia, which can see most of the rest of the sky, so we'll end up with better sky coverage.

can see most of the rest of the sky, so we'll end up with better sky coverage. So the data originates there, and do you have a special receiver or special equipment at the Arecibo Observatory, or are you sharing time with radio astronomers? We have kind of a unique setup that we call piggyback study, where we record data while other people are using the telescope for their own experiments. The way that Arecibo works is the dish is stationary in the ground, and there's this gigantic antenna platform that moves around above that. And by moving the platform, you can effectively point the direction you're looking at.

There's a main receiver there, and we have our receiver at kind of a counterbalance, so that as the main receiver moves across the sky, tracking a fixed point, usually in the sky as the Earth rotates, our receiver weeps in an arc about six degrees away from there. So we don't control where it points, but over long periods of time, the place we're looking at sweeps across the sky and statistically kind of fills in the entire sky. We're doing what's called a sky survey, which means that we're not looking at particular stars. We're covering an entire band of sky with billions and billions of stars in it. So we're recording data basically all the time, 24 hours a day.

The data gets written onto magnetic tapes. When we started the project, the network connection from Arecibo to the mainland was very slow. It was just a 56K modem, so we couldn't send the data through that. So we recorded onto these very high capacity cartridges called DLT tapes. We fill up about one of those per day and mail those in batches every couple of weeks up here to our lab in Berkeley, and the data gets sent out from our servers here. David, we're going to have to take a break in just a second here,

and then we'll come back to talk a little bit more about SETI at Home. David Anderson is the director of the SETI at Home project. He is up at his headquarters in Berkeley, California. We're going to hear more about SETI at Home on Planetary Radio right after this. 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. 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. That's PlanetarySociety.org. The Planetary Society, exploring new worlds. Hello again, everyone. Matt Kaplan back on Planetary Radio, where our guest is Dr. David Anderson,

the director of SETI at Home, with 4 million users processing data coming from the stars. David, again, thanks for joining us on Planetary Radio. When we finished just before that little break, you were talking about how the data gets to us from God knows how many light years away and then is sent out to people's computers. You mentioned a little bit earlier also what people see on their computer, but they set it up just like any screensaver, right? That's right. You just download, you pick an appropriate version of the screensaver. We have versions for Windows,

Macintosh, and Linux, and every version of Unix you can imagine. And you download the right version and install it, and it just acts like a screensaver after that. And for anybody who might be worried about having this connection, because you do have to, of course,

have an internet connection to be part of the SETI at Home project. Have you ever run into people who have some fears about this alien software taking over their computer? Well, a lot of people who have computers in high security organizations like nuclear power plants or something have legitimate concerns about installing any non-critical piece of software in their computer, and that's understandable. We've had no security problems related to our client in the three years we've been running. It's important to realize the client only makes outgoing connections.

There's no incoming connections that would let somebody break into your computer. It's all the client screensaver connecting to our servers. That's a very important point. How much data is actually processed? And I guess as an extension of that question, how much more data is there to process? I guess the amount of data coming in will be almost endless, particularly if you start picking up that data from the southern hemisphere. Coming in will be almost endless, particularly if you start picking up that data from the southern hemisphere.

The current rate is we're recording about 40 gigabytes of data per day, and the unit of data that gets sent to a particular computer is a third of a megabyte, which is pretty small. It goes through even a modem line in a minute or two. That will keep your computer busy for anywhere from 10 hours to 20 or 30, depending on how fast your computer is. The problem that we're working on, SETI, is it's fairly good in terms of how much computing you need per unit data. There's, of course, many other interesting scientific applications that can use this approach to distributed computing,

and they vary widely in terms of how much data you need to send somebody's computer to get an hour's worth of computer time. That's pretty amazing. You talk about a third of a megabyte, 333 kilobytes roughly, and it can take that many hours for a fairly up-to-date, powerful PC to process that. There must be some pretty heavy-duty computation going on there. Well, we're looking for all different kinds of signals, sine waves, waves that pulse on and off, sine waves that are drifting because the sender is orbiting or rotating,

so there's a variable Doppler shift. So it's because of the incredible range of signals that we're looking for that there's such high use of computer time. Well, the inevitable question, of course, is have you found anything interesting? Well, we might have. There's several stages to our pipeline of collecting what we call events, which are just blips in power or these things called gaussian that are signals that get loud and then soft again. The sources of these events, most of them are probably noise. Anytime you're listening to space, there's randomness, and if you listen to enough noise, you can hear anything that you're looking for.

A lot of them are what's called RFI, or radio frequency interference, man-made signals. Picking up a radar or a microwave or whatever. Yeah, or even somebody turning on their car or cell phones. These all produce RFI. So there's a second stage of processing that we do on our own computers to separate out noise and man-made interference. One of our basic tools is looking for the same type of signal at about the same frequency coming from the same place in the sky at two different times. So if we hear a one gigahertz signal coming from a certain star one day and then six months later,

then that's solid evidence that it's actually coming from the star and not coming from somewhere here on Earth. That phase of correlating all the raw events that we've gotten back from the screensaver is ongoing right now. That will yield a list of kind of score-ordered candidates, and then at some point we'll actually go back to the observatory and point the telescope at those places again and see if those same frequencies are still coming from those points.

And I guess we have to remember that you don't control where the great radio telescope at Arecibo is pointing. You're piggybacking, as I think you called it, so that you will have to wait for that day when you're able to say, hey, could we have a listen to this star once again? That's right. We have an application in with Arecibo for about a day of observing time. How many stars will you be able to cover in a day's worth

of observing? We'll be able to do about a thousand. Let's turn away, strictly speaking, from SETI for a moment to really what you've created in this incredible version of distributed computing. And of course, virtually all supercomputers nowadays are clusters or multiprocessor systems, and you've created a system with essentially 4 million processors across the globe. I think the success of SETI at Home has led to some other purposes that people are putting this model to, aren't they? Yeah. The amount of computing power that we have in SETI at Home,

measured in terms of the most popular unit, which is with teraflops, or trillions of floating point operations per second, we're getting about 45 teraflops per second. And that's more than the largest commercially available supercomputer by a pretty good margin. So people in other areas of science are looking at different problems that can use the same approach. There's an interesting project at Stanford called Folding at Home, which is basically starting off with human genome and kind of growing in a virtual sense the proteins that develop out of that, trying to set up a link between the gene sequence and the higher level functions

of proteins. There's another project at Oxford University that's just starting up that wants to use this approach to study long-term climate change and improve the accuracy of our models for simulating climate in the next century and to get a more precise answer to the question of whether there's global warming, for example. So currently, we're actually working with these projects to try to come up with a software platform or kind of a framework where we can all use the same software and basically have the same set of users participating in all of these projects, so that when one of them doesn't have any work to do, that the other ones can take up the slack,

of course with a provision for people to control which projects they want their computers to work on. Did you have any idea, David Anderson, when you first started to consider this about eight years ago, that it would be the success that it has turned into? Well, it is a little bit slightly beyond our wildest dreams. The inspiration for the whole thing actually came from the Apollo moon landing, which was in the 60s. There was a period when the whole world was excited about the possibility of humans going to the moon.

the whole world was excited about the possibility of humans going to the moon. And that really revved up people's awareness of science and it improved scientific education. The inspiration for SETI at home was to try to think of something that would have that same effect today, of bringing science into people's houses and breaking down that barrier between the public and the scientific laboratory. So that's really one of the things that we're excited about beyond just, you know, teraflops and doing SETI is getting the public actively involved in science.

David, you're obviously still welcoming new users to download SETI at Home, and they can find it and your website, which is quite excellent, by going to the Planetary Society website, planetary.org, planetary.org. Any words of welcome to anybody who might want to consider this? We welcome new users all the time, and we will be in the next few months launching a couple of new projects, both the Australian data project that I mentioned before and another project called AstroPulse,

which is going to reanalyze our existing SETI at-home data, looking for different phenomena. Actually, instead of looking for SETI, we're now going to be looking for these short pulses that are signs of evaporating black holes, a very exotic physical phenomenon that nobody has ever observed before, but our data may contain evidence of it. David, thanks

very much for joining us on Planetary Radio, and I hope that we can talk to you again certainly sometime after that day of observing that you get at Arecibo, when you get to take a second look at some of these interesting sources that 4 million people have helped you find.

Great. I look forward to it. Take care. Thanks a lot. I'm Emily, back with more random space facts. The first close-up images returned from Mars in 1965 by the Mariner 4 spacecraft revealed a surface that looked disappointingly moon-like, cratered and dead with no signs of life, intelligent or otherwise. Later, Mariner 6 and 7 revealed water-carved channels, and more recent discoveries about

past water on Mars have renewed the hope that life once existed on the red planet. But no conclusive evidence has yet been found of Martians living or fossil. For more information about Mars and science and popular culture, visit the Planetary Radio page on planetary.org. Join me for more random space facts on next week's show. Here's Matt with more Planetary Radio. The Planetary Society's Bruce Betts joins us for his regular What's Up segment here on Planetary Radio. Bruce, welcome back.

Thank you very much. What's up this week? Well, we've got one of the best meteor showers of the year this week, the Geminids, which every year put on one of the best, if not the best display, depending on the year. And this week they're going to peak on the night of the 13th. And so if you go out into the cold and look up and are patient, you will likely see some meteors looking like streaks across the sky. Let me ask, does this work for our listeners on the web in the southern hemisphere as well?

Yes, it should. Now, the number of meteors you see will depend to some extent on your latitude because they appear to radiate from one constellation, in this case Gemini, hence the name Geminids, but they streak across the sky. And so you should be able to see them from the southern hemisphere as well. But it's a good point to bring up. A lot of the other comments we make are somewhat focused on the northern hemisphere in terms of direction. But typically a lot of the things we talk about, like planets, you can see from either hemisphere.

Now we just have the Leonids. They just went by, quite literally. Is this a pretty significant meteor shower? Yeah, the Leonids have been particularly active the last roughly three years. And the Leonids are interesting because they're highly variable. And they go from being a meteor shower where you don't see many at all to one where you can see hundreds or even thousands in an hour and roughly on a over 30-year cycle. We happen to have been in one of the peak cycles recently. The Geminids are actually consistently, except for the Leonids' peak pulses, the Geminids are the most active meteor shower of the year,

coming in at, if you're at a dark site, it's seeing approximately 75 meteors per hour. They're also nice to watch because they tend to be somewhat slower than, say, the Leonids, which tend to be very fast. It has to do with orbits and where things are, which direction things are going. So you actually are more likely to see ones that slowly move across the sky as opposed to quickly. So Geminids, good stuff. A lot of people think more about the August Perseid shower as being a great meteor shower, and it is, but it's actually behind the Geminids.

But because it's winter and often cloudy and cold, not as many people are crazed enough to go hunting for the meteors during December. Understandable. Bruce, what else do you have for us this week? Well, we continue to have some nice planets to look at. You can see Saturn in the early evening. If you look to the east, it's the brightest thing off that way. If you go into the later evening and, again, rising in the east, you'll see Jupiter,

which will be brighter than any other object in the sky at that point. And then just before dawn, you look again, in this case, to the east, and you will see Venus and Mars, Venus at that time being the brightest object in the sky, Mars being much dimmer and reddish and to the upper right of Venus. Any space history milestones for us? We do have the 40-year anniversary of the first flyby of another planet by a spacecraft. 40-year anniversary of the first flyby of another planet by a spacecraft. That was Mariner 2 on December 14, 1962,

and its follow-up to last week's Space History, where we talked about the launch of the last Apollo. This week we have, again on December 14, will mark 30 years since the last astronaut walked on the moon. And the astronaut trivia for the day is, who was the last astronaut to walk on the moon? He answered, Gene Cernan. And let me go back to that mention of Mariner 2 for a second. Was that a flyby of Venus or Mars?

I'm sorry, it was of Venus. And what did we learn? Not much. No, we did learn some things, but at that point, in some ways, the greater feat was getting past it, as opposed to what we learned about the planet. But we started to

see data from the planet, which was followed up much more extensively by later probes. And certainly an auspicious beginning for a long history of magnificent flybys and other missions that have stuck around with some planets. Yes, definitely.

Bruce, that's about all the time we've got. We'll talk to you again next week, I hope. That sounds great. Thanks again. That has been Dr. Bruce Betts, the Planetary Society's Director of Projects, with his regular segment on Planetary Radio, What's Up? That's all the time we have this week. Please join us again next Monday at 5.30 p.m. Pacific Time here on KUCI.

You can also hear this and all of our other shows anytime you like at planetary.org. We'd love to hear from you. Send your questions and comments to planetaryradRadio at Planetary.org. Thanks for listening. We wish you luck in your own search for terrestrial intelligence. Planetary Radio is a production of the Planetary Society, which is solely responsible for its content. Our producer is Matt Kaplan.

Other contributors include Charlene Anderson, Monica Lopez, and Jennifer Vaughn. The executive producer is Dr. Louis Friedman. This edition of Planetary Radio is program number 0203 and is copyrighted by the Planetary Society. All rights are reserved.