Planetary Radio: Space Exploration, Astronomy and Science - A Bright New Star in the Search for Extraterrestrial Intelligence

Episode Date: April 3, 2006

Paul Horowitz talks about his new attempt to detect pulses of laser light from distant civilizations with the Optical SETI Dedicated Observatory.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Paul Horowitz and a bright new SETI star, 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. We are just a few days from first light for the biggest telescope east of Texas. This new instrument won't find any new planets, won't study the edge of the universe. In fact, it won't take pictures of anything. What it will do is watch for a brilliant flash of laser light telling us we're not alone. The search for extraterrestrial intelligence returns to our show with SETI pioneer Paul Horowitz and Harvard grad student Andrew Howard.

Later on, we'll get a new space trivia contest as we explore the night sky and check what happened this week in space history with Bruce Betts. Five, count them, five men are whizzing by overhead this week in the International Space Station. Men are whizzing by overhead this week in the International Space Station. Bruce will have more to say about the new Expedition 13 crew, but we can tell you that they've safely joined Commander Bill MacArthur and Flight Engineer Valerie Tokareff. MacArthur and Tokareff are near the end of their six-month float in the ISS. There's more news from Cassini. The Saturn orbiter has found evidence of what may be tens of millions of small moonlets in the rings. These missing link satellites, missing link, that's NASA's term, not ours,

may be proof that a much bigger moon broke up eons ago to form those beautiful circles of ice and dust. The big new rocks are probably about a 100 meters across. Remember how we reported an early dusk for the Dawn mission to the solar system's biggest asteroids? Well, thanks to a positive review from a NASA panel, Dawn has risen from the dead. The probe is back on track for its twofer mission to Ceres and Vesta. You can read the details at planetary.org. That's where you'll also find an update on the Mars Exploration rovers, both of which are in need of a car wash. Speaking of spirit and opportunity,

why do they have to take a day off now and then? We know who to ask. Here's Emily. I'll be right back with Paul Horowitz and Andrew Howard. Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, Recent updates on the Mars rovers have mentioned that Opportunity is operating on restricted sols. What are restricted sols and why do they only affect one rover at a time? When either rover is operating on restricted sols, it can only drive every other sol. One sol

is a Martian day, which is about 40 minutes longer than an Earth day. You might think driving restrictions arise from not enough power being available to the rovers, but in fact power has nothing to do with it. The problem lies in the difficulty of operating a landed Mars mission from Earth. Every single sol of the rover's lifetime, the mission operators have to look at YesterSol's data, figure out the plan of driving and science activities for the day, and then send a new Sol's worth of commands to the rover. Early in both rovers' missions,

these planning tasks took place over the rover's night times. As the rovers slept, their drivers would prepare the next Sol's activities. But the hundreds of people on the rover teams couldn't keep this up. Eventually, they had to switch to operating on Earth, not Mars time. Why does this result in every other day driving? Stay tuned to Planetary Radio to find out. The last time we heard from Harvard professor Paul Horowitz, it was part of our remembrance of beloved physicist Philip Morrison. If Morrison helped conceive the search for extraterrestrial intelligence, Horowitz is one of its adoptive parents. Paul has shepherded creation of some of the most innovative SETI projects on our planet.

His latest opus will be the most powerful optical SETI instrument ever created. Working almost around the clock with a team of students and with support from the Planetary Society, he is about to unveil a 72-inch scope specifically designed to catch brilliant but brief flashes of coherent light, a momentary flare of the giant laser another civilization might use to make first contact. Paul, first of all, I want to welcome you back to Planetary Radio. It's been a while since we've had you on. Yes, thank you. Last time, in fact, it was about midnight our time, and I was completely out of it.

I hope I do better this time. You did fine last time. I want to start with saluting you as a SETI pioneer, and along with your Berkeley colleagues, Dan Wertheimer and Jeff Marcy, an optical SETI pioneer, I thought I would ask you, first of all, about the significance of optical SETI, and let me put it this way. If you were E.T. and you wanted to start a conversation with somebody, would you build a big old radio transmitter or a big old laser?

That's a very good question. I'd probably do both. Radio is a very good method of communicating over galactic distances because backgrounds are very low. That is, the radio sky is very quiet. And radio waves have the great advantage that they can go right through the opaque parts of the galaxy. They cut through galactic smog like a hot knife through butter.

On the other hand, it takes much larger antennas, as you said, a big old radio antenna, to form a narrow beam, whereas with an optical searchlight, an optical transmitter, a telescope in reverse, one forms a very narrow beam with a rather small piece of apparatus. So maybe if I were an extraterrestrial trying to establish communication, I would use an optical transmitter, that is a laser and a big mirror, to target or try to establish communication with the nearby stars where I know exactly where they are and where I don't have a problem of opacity of the galaxy. And at the same time, I'd give a second government grant to build a radio telescope

to try to establish communication with the far-flung civilizations with which optical communication would be difficult because of the interstellar dust in our galaxy. That's a generous government there, more generous than ours apparently, which has been kind of reluctant to fund even the possibility of receiving SETI signals. And that, I guess, is why it's significant that this very impressive new instrument that you and your team have put together is about to take, I mean, are you calling it first light, just like with any other telescope? We've used that phrase.

Of course, we've had a little light through the telescope, we have to admit, but not with the detector in place. We're still actually assembling the detector in our laboratory as we speak, putting in 15-hour days. So it will be first light, although the actual event is going to be at 2 p.m. in the afternoon, which I'm sure your listeners will be aware it's not a great time to do optical astronomy. And that, of course, is the April 11, what, unveiling of this telescope? How do we call it? I guess we're going at the first light ceremony.

And that's Andrew Howard we hear in the background. Paul, maybe you want to introduce him. I guess he's a graduate student that's been working with you? Andrew Howard is my graying graduate student. He's a senior graduate student on this project. He's in his eighth year and will get his degree in a few months. project. He's in his eighth year and will get his degree in a few months. And he's been largely responsible for analyzing the data from our earlier targeted optical search, the Planetary Society supported, and now designing and building the chips and data processing for the AllSky

search that will be launched. Let's talk a little bit about that. You mentioned this detector and now these custom chips, which, Andrew, I guess you put together from scratch with no prior chip design experience? Yeah, I guess it's sort of the university model. I'm not an engineer by training, but I went to some engineering groups and learned how to design chips, and we put this design together over several years and sent it off to a fab, and now we have, well, almost 100 of these PulseNet chips, which form the computing core of the instrument that's going to do this all-sky optical SETI search. I'd like to brag about Andrew's chip, if I could, just a second.

Of course. Each one of these chips processes incoming data to the tune of a billion conversions per second on each of 32 channels. That's just a lot of numbers. But the full set of 32 chips that's part of this one detector array processes 3.5 terabits. That's 3.5 times a trillion. We don't talk in trillions, but anyway. Per second, and that's equivalent to the contents of all books in print every second.

Good God. and that's equivalent to the contents of all books in print every second. Good God. As I read the description on the Planetary Society website, I wondered if this kind of development in parallel processing represented by the PulseNet chip, I wondered if this might have applications elsewhere in science or in industry. I mean, have you done anything with this chips architecture that is truly, well, revolutionary may be too strong, but truly useful beyond looking for ET? Potentially some high-energy physics. People could modify this design and use it for looking for events in their detectors,

which have a similar time scale, and they use similar kinds of detectors, and they also have a problem of massive data parallelism. But it's really designed to do this job, to sit at the back of this 72-inch telescope and look for signals. We have had some interest, particularly from some high-energy people that ask me about it, and I always say to them, oh, you know, you don't want this chip. This is a SETI chip. Go make your own chip. But they sometimes come by and talk to Andrew about how he did it anyway.

Your light detectors are not solid-state. You're using photomultiplier tubes. Yeah, that's right. So, well, almost all of optical astronomy is done with CCDs, charged coupled devices, and these are the kind of detectors that are in the majority of digital cameras. And they have the property that you can integrate with them, that is, you can record the light for relatively long periods of time. Typically in astronomy, it's in seconds or minutes.

In digital cameras, you might do this for, say, milliseconds. But in optical SETI, we're looking for flashes of light which are nanoseconds long. That's a billionth of a second. A billionth of a second, a million times shorter than a millisecond. So we need something that can actually detect the individual photons of light as they come in. And that's what photomultipliers do. More from SETI explorers Paul Horowitz and Andrew Howard when Planetary Radio returns in a minute.

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 didn't just build it. We attempted to put that first solar sail in orbit, and we're going to try again. You can read about all our exciting projects and get the latest space exploration news in depth at the Society's exciting and informative website, planetary.org. Transcription by CastingWords 752-6387, The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. We're talking with SETI pioneer Paul Horowitz, Harvard professor of both physics and electrical engineering. Paul and his grad student, Andrew Howard, are telling us about the first ever telescope dedicated to the optical search for extraterrestrial intelligence. The 72-inch reflector and its amazing detector

have only a surface resemblance to other big scopes pointed at the sky every clear night. What makes it different from other telescopes used for astronomical research? The way I've often said it is it's the largest telescope east of Texas if it's a telescope. It is not of diffraction-limited astronomical imaging quality. And if it were, there's no way we ever could have afforded it. And the official name for an aperture like this is a light bucket, which is a rather condescending term. But what it means is that it forms a not-bad image of the sky, almost as good as your naked eye can do. The resolution is a couple of arc minutes.

The resolution of your eye is about one arc minute, which is about the size of the disk of Venus. But it just has huge aperture. And by relaxing the imaging quality of the telescope, you can make it much, much cheaper and lighter. And we had it built by a guy by the name of Ray Damaris down in Arkansas. And he put this thing together, the mirror, the primary 72-inch, the telescope mount, the secondary, which is 36 inches in diameter, which is, by the way, larger than almost everybody else's telescope. It's as large as the Princeton telescope that was used in our earlier search along with us.

And he brought the thing up and installed it, and that cost $50,000. That's the bargain of the century. In fact, I'm hoping that I can persuade him to do an encore, because as with the targeted search that we completed a couple of years ago, which has been written up now, we really realized that we're going to need a second confirming observatory when we run this experiment, because you always get occasional events that are caused either by natural events like charged particles or flashes of light in the sky from other sorts of things

or just electronic hallucinations that these detectors tend to have. Without a second observing telescope running simultaneously and looking at the same portion of the sky, there's no way you can rule those out. And it was only when Princeton came online alongside our optical search, targeted search, Only when Princeton came online alongside our optical search, targeted search, that we were able completely to understand that the events that we were seeing on the average about once per night were not coming from the sky. So eventually you hope that there will be a sister to this facility somewhere, a little geographically distant.

I hope eventually. It's a very short time, because I think that we're going to be overwhelmed with data in an experiment that's 512 times as comprehensive in terms of the number of detectors as the one that we ran before, and it was producing an event per night. And so I think that really when we have this thing running, that's the demonstration, that's the proof of principle that we're ready to build a second one. But we really must have the second one before we're going to have totally clean data. Paul, what will you be looking for? What kind of pattern? And then, as a related but separate question, if these flashes are truly or at least possibly brighter than the star that they'll be coming from

or that they'll be coming from nearby. Why haven't we seen them already? Yeah, those are very good questions. Well, what we're looking for is whatever it is that advanced civilizations do in order to establish contact with a new civilization. And, you know, people have been thinking about this one for a long time. Maybe it's radio, microwave, maybe it's optical, maybe it's in the radio. It might be a continuous signal, a transmitter simply left on, or it might be pulses.

There are people who can make good arguments for both, and in fact there are good arguments for both. They're complementary kinds of things. We think, in the case of optical, that the ideal strategy, if you want to establish contact, is to make short, intense flashes. Because in optical, you're always near a star. That's where civilizations tend to hang out. And you've got to overcome the light, the optical background of your star. What you can do is make a short pulse with lots and lots of energy in it. And even we on Earth now could outshine our star by a factor of 10,000 in the direction that we're

aiming our laser. So that's a good way to go. But I think I would add that it's not obvious that you shouldn't make a continuous signal of a very special wavelength, a special color. And in fact, Jeff Marcy has been mining some of his data that he's used to find planetary companions to extra solar stars to see if there are any funny little spectral lines lurking in the overall spectrum of the star that are not explained by natural phenomena. In answer to the second part of your question, you know, if they're going to do what we think is a reasonable strategy, make a pulse a billionth of a second long, an nanosecond, and let it be 10,000 or 100,000 times brighter than your star, and do that, let's say, once per second or once per minute, you won't see that with your naked eye, because the average amount

of light coming from the star is not much enhanced. It's only during that billionth of a second that it's really bright. So you need to have instruments that can resolve and be sensitive to light fluctuations on the scale of a billionth of a second. And as Andrew explained, that's not what astronomers generally do. They generally average over long periods of time to get a very careful spectra of stars, and you simply won't see it in such an average. But, you know, there's always the flip side.

Charlie Towns pointed out at a conference that we all went to about three or four years ago that it's not that much of an extension of Earth 2000 technology to imagine lasers that are 10 or 100 times more powerful than we can build, apertures for transmitting, that is, big telescopes or searchlight mirrors that are 10 times larger than, let's say, the Keck telescope. And that combination together, operated as a continuous laser rather than a pulsed laser, would produce a brightening of the star as seen from far away of a factor of two. That is, the star would double in brightness when you turn on the laser and stay that way. That's something that

that's a naked eye object. And of course it would, not only would it brighten, but it would turn a rather interesting color because lasers are monochromatic. So you might see a star sitting there and then it turns bright green for one second and then it turns back to whatever color it was and does that for a few minutes. So, you know, that's a weird that's a weird dude up in the sky there. That's going to

attract the attention of the Greeks and the Arabs and the ancient astronomers. So I think it's a weird dude up in the sky there. That's going to attract the attention of the Greeks and the Arabs and the ancient astronomers. So I think it's a good question. It's about as interesting a question as, you know, why aren't they here, the old Fermi paradox. And to these questions, we don't have good answers. We don't know much about other civilizations. Paul and Andrew, we are pretty much out of time. As this new instrument comes online, how will our listeners and other members

of the public be able to participate or at least keep track of what's happening? Well, we're developing a way to export some of this data to the Planetary Society's site so that members and the interested public and anyone can look and see at any time where the telescope is pointed, what stars are in its field of view, if it has any promising events that it's seen recently in that part of the sky. We will be able to look at how much of the sky we've covered, and at one sensitivity there will be maps of those things. These are things which aren't on the Planetary Society's website yet, but on or shortly after our April 11th launch, we hope to have that information up there and updated on a minute sort of time scale.

So just about real time. Great. Gentlemen, we are out of time. Matt, can I just add one final comment? Sure, Paul. Go ahead. Just to thank our sponsors. The Planetary Society has been our loyal sponsor now for a couple of decades, I guess.

for a couple of decades, I guess. But I should mention also that the Bozak and Kruger Charitable Foundation has also been a faithful supporter of our students and of our equipment and our lab during the same time and has contributed importantly to this project. And thank you guys for the thousands of hours that you've put in. Paul, you in particular, for so many years on the search for extraterrestrial intelligence. And good luck with this powerful new instrument. Thank you so much.

Thank you. Paul Horowitz is professor of physics and professor of electrical engineering at Harvard University, co-author of the classic work, The Art of Electronics. He is truly one of the SETI pioneers. Andrew Howard is one of his talented team members, a graduate student at Harvard. And Andrew, congratulations on your upcoming graduation. Thank you. I'm looking forward to being done. We're going to be back with Bruce Batts in this week's edition of What's Up, right after

this return visit from Emily. I'm Emily Lakdawalla, back with Q&A. What causes the Mars rovers occasionally to be restricted to driving only every other day? In order to plan a drive, the rover drivers need to know where the rover is and what the landscape looks like around it. Back when the missions were running on Mars time, the rover drivers would receive the critical rover health and location data every rover afternoon between about 4 p.m. and 6 p.m. local Mars time,

at which time the Mars Odyssey spacecraft would always pass overhead to relay the data to Earth. The mission team would plan during the rover's nighttime and uplink a set of driving commands in the rover's morning with the Odyssey passed between 4 a.m. and 6 a.m. local Mars time. But now that the rover drivers are operating on Earth day schedules, 40 minutes shorter than Mars sols, those critical Mars Odyssey overflights sometimes happen too late in the Earth day for the rover drivers to get the information they need. They have to wait until the following Earth day to plan, meaning that the rover cannot drive during that Sol.

This restricted Sol situation happens for periods of roughly two weeks at a time, after which Earth and Mars calendars line up more conveniently and permit everyday driving again. Got a question about the universe? Send it to us at planetaryradio at planetary.org. And now here's Matt with more Planetary Radio. at planetary.org. And now here's Matt with more Planetary Radio.

Time for What's Up on Planetary Radio. Bruce Betts is back. He's the director of projects for the Planetary Society. And that means he comes in every week to tell us what's going on in the solar system and get forced to watch a little bit of a Star Trek episode with me because it was still on when he came back here. It was that cool Halloween one where they must have had a good time because they all got to put on cool makeup. And Barclay turns into a spider and, you know, all that good stuff.

And you don't know what I'm talking about. Do we pay you for this? Yeah. That was on the clock. Cool. What's up in the night sky? Well, we've got spiders and hissing cockroach Klingons and all sorts of things. Watch out for them.

But in addition, there are our regular friends, the planets. In the pre-dawn sky, Venus, brightest star-like thing up there. Can't miss it. Hanging out in the east before dawn. If you're really crazed, and most of you probably are, you can go looking for Mercury. It's tough right before sunrise, very far to the lower left of Venus, but you might get a shot at Mercury also looking like a bright star, but much less bright. In the evening sky, we've got Mars.

You can see just after sunset, it's getting lower and lower in the west in the early evening, looking kind of reddish and hanging out around Taurus and actually hanging out between the hanging out around Taurus and actually hanging out between the horn tips of Taurus. Jupiter, it is rising around 9.30 p.m. these days and another really bright star-like looking object. Take a look through binoculars or small telescope if you can. Check out those Galiland satellites.

We'll come back and talk about those a little bit later is that the kind of tease i'm supposed to do yeah that's a good tease okay good thanks okay saturn also up in the evening sky looking kind of yellowish and you can see that high up in the early evening between gemini and leo it's just a constellation type show for me. Moving right along, this week in space history, it's the 15th anniversary of the launch of the Compton Gamma Ray Observatory, one of NASA's so-called great observatories. And it was active until 2000 when it plunged back into the Earth's atmosphere and took all sorts of cool gamma ray data across a huge part of the gamma ray spectrum.

It was a very successful one. It was very, very successful indeed. Now, coming up this week in space history that we'll report on next year, Venus Express orbital insertion is on April 11th. April 11th for the Venus Express European Space Agency spacecraft to go into orbit around Venus. First time anyone's put anything in orbit around Venus since Magellan in the early 90s, so it should be fun. Look for that. Of course, Mars Reconnaissance Orbiter successfully getting into orbit a few weeks ago, so here's hoping. We have a human space update this week because we've got the next, the Expedition 13 crew headed to the International

Space Station. They've launched. They're going to hang out up there. Commander Pavel Vinogradov, NASA's science officer, flight engineer, and who knows what he devolves into, Jeff Williams, and Brazilian Space Agency astronaut Marcos Pontes, who will be there for an eight-day stay, hanging out with the current astronauts, then Pontes, and the current astronauts up there, MacArthur and Tokarev, will be heading back to Earth on April 8th.

On to Random Space Fact! Those astronauts, cosmonauts, launched aboard a 162-foot-tall Soyuz rocket. That's right, the rocket was 162 feet tall. There's your Random Space Fact, true to random. So 162 feet, I didn't your random space factory random. So 162 feet. I didn't know how high a Soyuz was. How does that compare with, let's say, the space shuttle when it's all put together? The space shuttle, the complete stack is a little bit taller.

It's 182 versus 162 feet. Well, good. Thank you for asking that. Well, good. Well, good. Okay, good. Moving on to the trivia contest, we ask you, name a place in the solar system, other than Earth, where you can find a palimpsest. Palimpsest. You just want to go in and pop it.

Gross. Do you want to explain that first? Tell us what the term means, first of all. A palimpsest in a planetary geology context is an impact crater where the surface has basically reflattened, but you still have evidence left over, often an albedo. That's a fancy word for light or dark variation compared to the surroundings. It'll be circular shaped. And so you tend to see these on icy bodies is the type of place where the ice relaxes. And you're still left with some indication, compositional indication, that you had something going on there.

And you may see secondary craters still out from it. But other than that, it just looks pretty flat. Well, you did specify these had to be on some other planet. We had a couple of people, actually, who very cleverly mentioned places on Earth that might exhibit evidence of palimpsest, some of them actually even human-caused, previous cities or villages being mostly but not entirely obliterated by newer ones. But our winner, who had what we were really looking for, was Ilya Schwartz, Ilya Schwartz of Ellicott City, Maryland. And you're going to get an Explorer's Guide to Mars poster.

He mentioned Ganymede, but I guess there were a couple of possible answers. Ganymede's a really good answer. So is Callisto, possibly even Europa. Then a lot of the large icy satellites have or may show palimpsests. What's up for next week? What's up for next week? We've got what is the escape velocity from the moon?

From the surface of the moon, how fast do you be? Do you have to go to escape the gravitational pull of the moon? This is just the moon, not the Earth-Moon system. So what is that escape velocity for the moon? Go to planetary.org slash radio. Find out how to email us your

answer and compete in the next fabulous trivia contest. And get your entry to us by Monday, April 10 at 2 p.m. Pacific time. Monday, April 10, 2 p.m. Pacific. You'll be part of the next competition and maybe you'll win an Explorer's Guide to Mars poster. We got to go back to t-shirts someday soon, but not quite yet. We better get out of here, too. Yeah, I hear it coming. It's almost T-shirt season again. Yep.

Yeah, yeah. All right, everybody, go out there, look up in the night sky, and think about how important paper has been in your life. He's Bruce Betts. He's the director of projects for the Planetary Society. He joins us each week here for What's Up? Live long and prosper, bro. Right on.

We'll be back with far more far-out news from around the solar system and beyond. Planetary Radio is produced by the Planetary Society in Pasadena, California. Have a great week, everyone. Thank you.