Planetary Radio: Space Exploration, Astronomy and Science - An Optical SETI Update From Paul Horowitz

Episode Date: July 18, 2011

An Optical SETI Update From Paul HorowitzLearn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

The search for extraterrestrial intelligence continues this week on Planetary Radio. Welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. Paul Horowitz isn't listening for aliens anymore. No, he's looking for E.T.'s flashlight. The leader of the Harvard Optical SETI project returns to our show to tell us about the latest innovations aiding his search. Bill Nye will join us from an amazing meeting. In fact, it's the amazing meeting in Las Vegas. And Bruce Betts will help me give away two copies of Moonshot, the enhanced e-book. That will be right after he tells us about the night sky and a very big week in space history.

As we finish this week's program, Shuttle Atlantis' last mission, the last for any of the current space shuttles, was moving smoothly toward its return to Mother Earth on July 20th. That's the 42nd anniversary of the first landing of humans on the moon. Time sure flies when you're having fun. You don't have to look farther for proof of that statement than our weekly visit with Emily. Emily Laktawalla, the Science and Technology Coordinator for the Planetary Society, has returned from Hawaii, and you've got the girls who are there in the background,

so we're just going to listen to them quietly playing as you tell us about what must have just been geologist equestrian heaven. It was kind of a funny combination. But yes, I rode on a horse down into the middle of Haleakala, the main volcano on Maui last week. That was pretty exciting. It was like walking down into Mars. It was quite stunning. Wow. Well, that's at one end of the spectrum. At the other end of not so great news is all the stuff that's been going on in Congress. And particularly, we will talk about the James Webb Space Telescope, which the House Appropriations Committee has canceled the funding for. Now, we rarely, if ever, touch on

politics in your segment of this program. But I think it's appropriate here because you've posted some interesting stuff. I had prearranged for lots of blog posts to be posted during my absence, but I didn't wind up needing all that material because this news about the cancellation of James Webb is such a shock and we had to write so much about it. And we're still asking our members and readers and anybody who cares to contact your congressman and tell them what you think about this proposal to slash NASA's budget so deeply. Personally, this made me think of a video that I actually saw for the first time a couple of months ago, but now seemed the appropriate time to post it of the Vlogbrothers talking about the top five most awesome things about the Webb telescope. But in their introduction to this piece, they made this generalization, this succinct generalization

about why space exploration is important that I just thought was awesome. People are always like NASA's money could be better spent on services for humanity. And to them I say, I do not want to live in a world where we only focus on suck and never think about awesome. We also have to make good things happen. And that is why I love the James Webb Space Telescope. Well, it is a July 15 entry in the blog at planetary.org. And Emily, because you've got a lot going on, we're going to leave it right there and hope that people will go and take a look. Emily, thanks very much, and we'll talk to you again next time.

Thank you, Matt. Emily Lakdawalla is the Science and Technology Coordinator for the Planetary Society and a contributing editor to Sky and Telescope magazine. Back in a moment after we hear from Bill Nye. Hey, Bill Nye, the planetary guy here, Executive Director of the Planetary Society. And I'm delighted that Emily and Matt have been talking about the James Webb Space Telescope. I'm in Las Vegas, Nevada at something called the Amazing Meeting, TAM, which is sponsored by the James Randi Foundation. He worked as a magician for many, many years as the Amazing Randi. And these are people that promote critical thinking,

skepticism, and so on. And I was on a panel with none other than Neil deGrasse Tyson, Lawrence Krauss, and Pamela Gay, the astrophysics, astrophysicist, astronomer party. It was fabulous. And we talked about the future of the space program in the United States, which affects space programs all over the world. You know, you talk to people in France, they know more about what's going on at NASA than they do at the European Space Agency. It's a strange turn of events. But the James Webb Space Telescope could be canceled,

just apparently out of spite, just to show the National Aeronautics and Space Administration they've got to bring things under budget. Well, that's not how you move forward, everybody. That's not how you engage future generations in the enterprise of science. It's not how you look for the dark energy and dark matter that might be holding the whole universe together and we can't quite find it. It's not how you inspire people.

At this meeting, you meet people who love science, who love the process of science, who love, dare I say it, the joy of discovery. And that's what this is all about. That's what space exploration is all about. Looking over the unknown horizon because you don't know what you're going to find there. So let's support the James Webb Space Telescope. Let's support commercial transportation to low Earth orbit. And let's come up with new missions to take people farther and deeper into space.

It's another turning point in the history of space exploration. By listening to this radio cast, you are part of it. Thanks! I gotta fly. Bill Nye, the Planetary Guy. The optical search for extraterrestrial intelligence has a history that began not long after the first suggestions that we humans might be able to eavesdrop on our galactic companions, assuming there are any. The problem was that optical SETI was no more than an interesting concept for many years. Harvard professor of physics and electrical engineering Paul Horowitz used his electronic wizarding skills to build several of the most advanced radio SETI receivers before he turned to looking for laser flashes that would tell us we are not alone.

As with his earlier searches, Paul and his talented students have pushed a steady advance in optical SETI technology. I asked him to come back to Planetary Radio to tell us about his latest two innovations, but also about why he is so devoted to this search for a signal that may never be found. Thank you, Matt. It's a pleasure to talk with you about my most favorite topic. Thank you, Matt. It's a pleasure to talk with you about my most favorite topic. Now, you have done an awful lot of things in your professional life.

What is it about SETI that just keeps you so enthusiastic, so excited, and so full of innovation? You're in your team there at Harvard. Well, I guess a bunch of things. One is I'm basically an instrumentation nerd, and SETI is something that capitalizes on the best that you can build at the current time, the best receivers, the best optical telescopes, the best detectors. I just love that kind of challenge. I love the fact that the field isn't particularly crowded. It's not one of these things where there's 20 teams doing the same thing, and you have to basically always worry that somebody's going to get the scoop on you. It's a very friendly community with just a few groups.

And in this business, it's all open. You know, we all talk about what we're doing. We give each other all our plans and circuits and everything. And we wish each other well. Yeah, well, and hopefully no matter who makes that big find, everybody will own a little piece of it because of that. Yeah, it's sort of all, we've all discovered it if anybody discovers it, you know what I mean? Yeah, that's good.

I think that, and plus, it's one of the most deep questions that humans can ask. Are we alone? And the answer, if we can make contact, would just have astounding implications. It would be the greatest discovery in humankind. I think all those things together combined to basically keep me obsessed with this search. Paul, I think you are in the running for king of the instrumentation nerds, actually. You don't even have to look farther for evidence of that than what you guys have been doing with this search. Could you very briefly review what is underway there with this 72-inch telescope not far from Boston? Sure.

Matt, well, of course, we graduated from the radio days. We had an 84-foot radio telescope here, and we built a multimillion-channel, up to almost a billion-channel radio receivers to go on this thing. And then we switched over to optical, largely from Charlie Towns and Dan Wertheimer's influence, who taught me that this was an altogether reasonable alternative to radio communications over galactic distances. We started first with a targeted search, piggybacking on a 60-inch, 61-inch telescope that existed here, still exists, the largest telescope east of the Mississippi, by the way. And we searched some 5,000 or 6,000 different stars that are similar to our own, looking for optical flashes of the sort that could easily span the distance between stars. We've now gone to an all-sky search mode, and we built our own 72-inch optical light collector or light bucket.

It's not really full astronomical quality. We built it on the cheap. I guess if it is a telescope, it's now the largest telescope east of the Mississippi. And we outfitted it with a very interesting array of detectors that can look at a whole stripe of the sky with individual very fast responding pixels for short pulses, nanosecond flashes of light of the sort that we could make and that we assume other civilizations could just as easily, in fact, probably more easily make. The search that we've been running so far uses a thousand such pixels of nanosecond speed. We look at all these pixels all the time.

We're therefore doing about a tera sample per second, that is a thousand billion measurements per second of this stripe of the sky. And as the earth turns, it carries the stripe around through the sky. We've covered the entire northern sky now three or four times over the five years or so that we've been running this experiment. That's sort of where we are right now. And we're about to make a big upgrade to the system. We'll talk about that upgrade in a second, but what does this mean, that you've been able to scan the sky four times? Does that mean that it's that much less likely

that we're going to see that signal, or is there really good reason to keep at this? Well, of course, you know, each of these experiments, as you look, let me take a step back. When you look at SETI, we have some technology on Earth that's improving with time. We take what we can do and we make a search. Our search is limited by the ability to look at each spot in the sky for only about a minute.

It's limited by the sensitivity of our detectors, which is only in the blue end of the visible spectrum right now. But I could talk about what we're going to do about that. So in covering the sky four times, we haven't been looking at the entire sky all the time, four times. Each spot in the sky has been given about a minute to speak its turn. And if it didn't happen to come then, then we will not have seen it. This is a weakness of essentially all the SETI activity that's gone on on Earth. We don't have full coverage, full sensitivity all the time. So what are we sensitive to? A civilization that is sending a nice strong signal in the wavelength that we can receive at the time that we happen to be looking in their direction. That would take a lot of persistence. Under some scenarios, that could

certainly happen. An advanced civilization sufficiently enthusiastic about making contact could certainly make the kind of signals that we could see now. But maybe it's expecting a lot. SETI moves along step by step. What we do with each search so far is to eliminate some scenario that could have been altogether reasonable but seems not to be. So the radio searches, for instance, have pretty much eliminated the scenario that there are some very strong radio signals in the sky that transmit continuously and with sufficient power that we could see it when we point our feeble telescopes at it for a few minutes.

are some planets that are about the right size and about the right distance from their stars, that we ought to just be staring at those, which I think is something that, you know, your colleague who you mentioned, Dan Wertheimer at Berkeley, is given a shot at. Sure. If you can narrow the target list, that's great. For instance, in our targeted optical study, we only looked at sun-like stars within reasonable distance from Earth. And Dan, of course, is doing this with, I think, the Green Bank Telescope is now engaged in some targeted search at some of the Kepler objects. That is the known extrasolar stars that have planetary companions that suggest planetary systems and perhaps habitats for life.

I guess the other way to say it, though, is that from these planet searches, which are fairly recent, the way you know jeff marcy and guys like that we now know that something like five or ten or twenty percent of stars probably have reasonable habitats for life around them so limiting yourself perhaps to a half a dozen that kepler happens to have seen would seem to me perfectly reasonable but why not just look at everything if twenty percent of them are going to have planets anyway you have a much bigger target list yeah if you only look at 10 or If 20% of them are going to have planets anyway, you have a much bigger target list. If you only look at 10 or 20 targets, and that's really all we have from Capoeira that are reasonable, maybe 50, then you're sort of asking that 1 in 20 or 1 in 50 harbor a nice, strong transmitting civilization. Whereas if we look at everything in the sky, albeit briefly, we've got millions of possibilities.

So I'd still stick with my all-sky search that we have, although it certainly is reasonable to do also a much more intense search of the ones where you think there's a greater chance. Harvard's Paul Horowitz. He'll be back in a minute to tell us about the electronic magic he hopes to implement in his search for alien civilizations. This is Planetary Radio. I'm Robert Picardo.

I traveled across the galaxy as the doctor in Star Trek Voyager. Then I joined the Planetary Society to become part of the real adventure of space exploration. The Society fights for missions that unveil the secrets of the solar system. It searches for other intelligences in the universe, and it built the first solar sail. It also shares the wonder through this radio show, its website, and other exciting projects that reach around the globe. I'm proud to be part of this greatest of all voyages, and I hope you'll consider joining us.

You can learn more about the Planetary Radio Planetary Radio Welcome back to Planetary Radio. I'm Matt Kaplan. The search for extraterrestrial intelligence is far from Paul Horowitz's only effort. The Harvard professor of both physics and electrical engineering is still teaching and inspiring students and working on the next edition of The Art of Electronics, considered by many to be the Bible of its field,

yet SETI remains his most favorite topic, as you heard him say a few minutes ago. He and his team continue to push the edge of the technology envelope, always refining the ability of humanity to receive the message that will tell us we are not alone in the universe. Talk about the electronics that continue to evolve. Your team there, I mean, we've had some of your graduate assistants on in the universe. Talk about the electronics that continue to evolve. Your team there, I mean, we've had some of your graduate assistants on in the past who've helped you do this incredibly innovative work. How are you able to process these observations that are coming so fast? What's enabled you to do this? I guess the march of technology. You know, I look back at the stuff we built back in the Meta project, the Million Channel Radio.

Which was pretty impressive at the time. Yeah, you know, it is two racks of equipment. It took us, it had a million solder joints, it had thousands and thousands, 7,000 memory chips in it. And it had a big banner that, a self-bragging banner on the top that said, Meta Supercomputer, supercomputer colon 60 million operations per second. And at the time, it's really quite humorous now, but at the time, that was a supercomputer. Now it's a joke. You know, any cell phone does better than that.

So then we moved to beta, and we got a lot faster. Then with our optical searches, we've gone on to microprocessors and custom chips. The optical search we're doing now uses a set of custom chips designed by Andrew Howard that can do this trillion samples per second. But that's now outclassed. And in our upcoming upgrade, we're going to build a system that's basically 16 times as powerful using what are called FPGAs, field programable gate arrays, which is the latest and greatest incarnation creature out of

Silicon Valley. And it's going to allow us to do a much more thorough job on this all-sky optical search. How are those coming along? Are you working on those boards? Yeah, the boards are done. We have the daughter boards in hand. The code works in them. The electronics all works. The motherboard is out for fab and should come back in about a month's time. And at that point, we'll be ready to take the camera off the telescope and retrofit it with this new system, which will basically give us not only 16 times as much capability to transfer data, but will also give us about 10 or 20 times as much data per channel of these 1,000 channels. What does Cherenkov radiation have to do with this?

I know that as the pretty blue glow that used to come up from the nuclear reactor at the university that I went to. Yeah, okay, so Cherenkov radiation, named after a Russian, a spectrum of stuff that includes light, so you can see it. It comes from particles that are basically breaking nature's speed limit. If you have charged particle moving faster than the speed of light, then it emits a shock wave, which is called Cherenkov radiation. How could it be moving faster than light? Yes, interesting. How do you break Einstein's speed limit? Yeah, it's against the law. You do it. You can't move physically faster than the speed of light, but the speed of

light may be less than the speed of light in the material that you're moving through. So an electron can move through the atmosphere at something very close to nature's speed of light. And light, since it goes slightly slower in atmosphere, you're breaking the speed limit there, and that produces this shock wave. And the interest to us, of course, this happens in these reactor ponds because you have high energy particles given off by these decaying isotopes. And they're going through the water in which the speed of light is only two-thirds the real speed of light. The relevance to SETI and optical SETI in particular is that there are high energy particles coming into the Earth's atmosphere from out there. And they're breaking the speed limit in the atmosphere. And so they make little flashes of light, which have been known for quite a long time.

These flashes of light, they're natural. As far as we know, they're not made by creatures. But they look a lot like what you might expect. It's a brief blue flash of light. And one of the big jobs in this optical setting, as in any setting, is to discriminate the natural backgrounds from the thing you're really interested in, which is the artificial signal generated out there for our receipt. In optical SETI, Cherenkov radiation is one of the big natural backgrounds. Another one is

lightning flashes. Sometimes it's an airplane flying through our telescope. We have beautiful little pictures of an airplane track going straight for the bullseye, and then you get this huge blip. We've been able to discriminate that one pretty well because we have this camera that stares at the whole sky all the time and gives us nice pictures. The Cherenkov is much tougher, and a lot of the objective of the new system is to make it possible to characterize much better

the nature of the trigger that we've seen so that we can discriminate these natural Cherenkov flashes from the thing we really care about, the artificial laser flash. Tell us where you hope to go next. And what I've read is that you hope to go beyond the light that we can see. Yeah. Our detectors, as I said earlier, that we have now only go from the blue or the ultraviolet into about the middle of the visible range.

We'd really like to go much more toward the red, and I'll tell you the reason in a second. But the reason we have what we have is you have to use what you can get, and it's very hard to go into the red and infrared with detectors. At least it was 10 years ago when we bought these things. Now there's some very nice detectors that go out into the near infrared, really quite stunningly good. The reason to go into the infrared, and the reason that Charlie Towns originally suggested infrared, is quite stunningly good. The reason to go into the infrared and the reason that Charlie Townes originally suggested infrared is threefold. The galaxy is much more transparent infrared. In the visible, you can't see the galactic center. In fact, you can't see most

of our Milky Way galaxy. You're just seeing the near parts. In the infrared, you can see clear to the galactic center. A second reason is that stars are much dimmer in the infrared, so there's much less background. And the third is that photons are much dimmer in the infrared, so there's much less background. And the third is that photons are much cheaper. Infrared is lower energy, so you get a lot more photons. So for all these reasons, you really want to go red. And nowadays, you can get these detectors. We bought one sample.

They're hideously expensive, about $4,500 a piece. And it's terrific. We've tested it in our lab, and we only need 15 more of these things. And then we'll be set to do a search that pushes much more into the region that we want to be, which is much more continuous observation in the part of the spectrum that makes a lot more sense for interstellar communication. Paul, it is always an exciting pleasure to talk to you. Your enthusiasm is infectious and I hope that that money to buy those additional tubes is on its way. We look forward to hearing more as this search for extraterrestrial

intelligence in the optical range continues to become more sophisticated, and best of luck to you. Thank you, Matt. It's a pleasure talking to you. Paul Horowitz is the longtime professor of physics and separately of electrical engineering at Harvard University. Back about, well, more than 30 years ago now, he co-wrote the first edition of The Art of Electronics, still very much in print and very much in use as a textbook around the world. But we know him as the head of the Harvard Optical SETI Search. That's a topic we'll be coming back to again in the future. You can learn much more about this at links we have on the show page.

Just go to planetary.org. But there is a whole SETI section on the Planetary Society web page. You can read about Paul's work and about the work on the southern hemisphere and elsewhere that is helping us to discover once and for all, are we alone? Well, I know I'm not alone when we get to the What's Up segment. I'll be talking with Bruce Betts about What's Up in the Night Sky in just a few moments. Bruce Betts is on the Skype line. It's time for What's Up in the Night Sky and a whole bunch of other good stuff.

And we're going to give away a book. Moonshot is going to be our prize, and we're going to give somebody a chance to win another copy of that book. Welcome back. How are you doing, Matt? I'm okay. I had a good time looking at the sky. It was overcast much of the time. We just got, minutes ago, got back from vacation in central California, but there were a couple of times I was able to go out and do my best to recognize a constellation or two, and I saw some of the stuff that you tell us about. What's up? Saturn up in the evening, pretty low, getting lower and lower in the west-southwest after

sunset. And if you look to the left of it, you can see similar but bluer Spica, a bright star. It still has the faint Poryma star, only about one degree away from it. Also after sunset, you might be able to see Mercury, but it's very low down towards the horizon in the west-northwest in twilight. If you're up after 1 a.m. or up in the pre-dawn, you can see super bright Jupiter high overhead in the pre-dawn, looking quite spectacular. We move on to this week in space history. Of course, this is the anniversary of the 1969 moon landing of Apollo 11, first humans on another world, and also seven years later, 1976, Viking 1 landed on Mars.

Great, great occasions, wonderful anniversaries, and we're going Mars. Great, great occasions. Wonderful anniversaries. And we're going to celebrate that moonshot especially. We will indeed. We move on to random space fact. Ah, a jaunty little tune. Shuttles. Got to talk space shuttles some more. I'm still feeding out the spacetle random space facts on my Twitter account,

at random space fact, all one word. In this case, it's always seemed kind of baffling, the various numbering schemes for Space Shuttle over the years, so I've broken this down. The first nine were named nice and numerically STS-1 through 9. Then they went to the confusing terminology with the STS-41B, where the first digit, of course, referred to the last digit in the fiscal year. Then the second digit was always 1, because it was designed to be a 1 for a Kennedy launch, and 2 for Vandenberg,

which they never developed and used. And then it was labeled alphabetically within the year based upon the scheduled launch. They then, after Challenger, threw all of that away and went back to numerical launch and launched numbers again with STS-26. But of course, they would sometimes launch out of order because they were numbered based upon the schedule, not what actually happened. There it is, the simple shuttle numbering system. Can we go back to talking about general relativity? Because I think it was much easier to understand. At least it had a physical basis. No, but we can move on to the trivia contest. We asked you, what was the first NASA rocket launch attended by a sitting U.S. president, meaning still in office as president at the time.

How did we do, Matt? Well, of course, the key term there is sitting, though several listeners pointed out that probably Richard Nixon was standing during the launch. And in fact, we were sent by Ilya Schwartz a connection to a NASA photo of Richard Nixon standing to the then NASA administrator Tom Paine with this poor, drenched aide, a young woman with an umbrella over Nixon. It was a rainy day. Indeed, they were standing for the launch of Apollo 12.

And so that was it. That was the very first one with a sitting president. And I am very happy to tell you that it was Ed Lupin, our friend down in San Diego, California, a regular listener. It's been almost a couple of years since he's won the contest. I'm also proud to say we're going to get Ed a copy of that e-book, that enhanced e-book, Moonshot, How Appropriate for the 42nd Anniversary of Apollo 11, by Jay Barbary, the guy that we talked to a couple of weeks ago on this program.

That's going to come to Ed from NetGalley, the place online where people can get tomes like this. It's quite excellent. I recommended it highly, and I'll do that again. And we're going to give another copy away right now with your new question. Cool. We return to the space Shuttle program and its long history. Not counting the current mission, STS-135, not counting 135, how many times did space shuttles land at each of their three landing sites? Kennedy Space Center, Edwards Air Force Base, and White Sands, New Mexico. How many times did it land at each of those, not counting STS-135? Go to planetary.org slash radio, find out how to enter. And you have until the 25th of July, Monday, July 25, at 2 p.m. Pacific time, to get us that answer. And we're all done. All right, everybody go out there, look up at the night sky, and think about propellers.

Thank you, and good night. I always wondered why they didn't just put a propeller on the space shuttle, because that would have allowed them to come around again, right? Exactly. I'm sure there would be no issues whatsoever with that during hypervelocity flight. He's Bruce Betts, the Director

of Projects for the Planetary Society. He joins us every week right here for What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California and made possible in part by a grant from the William T. and Eileen L. Norris Foundation. Clear skies and now for what is really the last time, Godspeed Atlantis. Thank you.