Planetary Radio: Space Exploration, Astronomy and Science - Exoplanet Finder Debra Fischer

Episode Date: March 23, 2009

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Closer and closer to finding another Earth, this week on Planetary Radio. Hi everyone, welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. Final Frontier. I'm Matt Kaplan of the Planetary Society. Deborah Fisher and Jeff Marcy have discovered more than half of the over 300 exoplanets found so far. But new technology is needed to help us sniff out another planet like our own. Deborah will tell us about an experimental system that may do the trick. She'll also talk about what it's like to discover new worlds.

Bill Nye, the science and planetary guy, will bring us news from space about a deadly bacterium. No, not the Andromeda strain, just plain old salmonella, but with a zero-g twist. Emily Laktawalla looks back at the Galileo mission to Jupiter and its tiny probe that plunged into that giant planet's atmosphere. And there's more good news from Bruce Betts in this week's What's Up. You said enough with the calendars already. We listened. It's back to Planetary Radio t-shirts with this week's space trivia contest. What? Another big rock narrowly missed our pretty little sphere?

It was just last week that we told you about a different close call. This time it was a near-Earth object that's about 15 meters across, and it came within 80,000 kilometers of home sweet home. That's only about twice as far as geostationary satellites. The story is at planetary.org. Space Shuttle Discovery's crew continues its work at the International Space Station. The last set of solar panels were unfurled without a hitch last week, but there were some other minor problems. Liquid water has been seen someplace other than Earth for the very first time,

and I bet you can't guess where. It was detected as condensation on a leg of the Phoenix Mars lander. Why didn't it freeze, you ask? For the same reason you cold climate types spread salt on your roads. And there are plenty of salts and other minerals near the Martian North Pole. The findings will be presented at this week's Lunar and Planetary Science Conference in Houston. I'll be right back with planet finder Deborah Fisher. Here's Bill. Hey, hey, Bill Nye, the planetary guy here, vice president of the Planetary Society. I'm on the road this week. I was at the National Science Teachers Association meeting here in the United States, and Neil deGrasse Tyson and I did

sort of a tag team lecture covering all kinds of space topics, and we met many members of the Planetary Society. It was good to meet you. Thanks for coming up to us. Now, this week, while we were spinning around here down on Earth, astronauts on the International Space Station investigating bacteria seem to have found a way to control how infectious, how virulent the Salmonella bacterium is. Now, look, everybody, I'm the first guy to be skeptical of the value, Salmonella bacterium is. Now look, everybody, I'm the first guy to be skeptical of the value, the great cost, the great expense of what NASA calls microgravity research. Other people might call it zero gravity research, zero g research, but they really might be on to something. Now,

making something like Salmonella more dangerous doesn't sound like a great idea, but being able to control how dangerous it is, that's a fantastic idea. See, we have a worldwide problem where antibiotic drugs are not as effective as they used to be. These bacteria are mutating. If we can find a way to control how they mutate or control how they infect us, we might be able to, dare I say it, change the world. It's a classic example of somebody might ask, why are you guys doing this kind of research way above the Earth's surface? Well, the answer is we don't know what we're looking for. That's why we're looking. Well, thanks for listening. I'm going to fly. I'm Bill Nye, the Planetary Guy.

It used to be that discovering just one planet got your name in history books forever. So what happens when you discover scores of them circling other stars? Mostly, you keep right on discovering. That's what Deborah Fisher has been doing. The San Francisco State University astronomy professor has enjoyed a tremendously successful collaboration with UC Berkeley's Jeff Marcy. All of the so-called exoplanets found so far are a good deal larger than Earth. Everybody's pretty sure that other Earths are out there, it's just that our instruments haven't been sensitive enough to detect them. New space telescopes like Kepler and new Earth-bound technology may change that. Debra is pinning her hope on an innovation in fiber optics called FINES. Debra, after talking

to your associate Jeff Marcy several times on Planetary Radio, it is really a delight to get you on the show as well. Thanks for joining us. Thanks, Matt. It's a pleasure to be there. So tell me, is it safe to say now that our galaxy, the Milky Way, is filthy with planets? I think that's a good approximation. Yes, it's true that we're finding planets around a significant fraction of stars, something like 10 or 15 percent of the stars. But if you think about the biases in our technique, it means that there's actually a significantly larger population of planets

that we're simply not able to detect yet. Most of the planets that we've found have been similar to Jupiter or Saturn, fairly massive objects that are 100 times the mass of the Earth or more. And so our hope, of course, is to get down to lower-mass planets for the near future. And the hope, of course, is that there are plenty of those lower-mass planets, planets that are a good deal smaller than Neptune, like the one we live on. That's right. I think nature would really have to be conspiring against us to have the sort of signature that we see.

In other words, when we look at the mass of planets that we're detecting now, we see that we find far more of the low-mass planets than the high-mass planets. And that's pretty suggestive. This goes, you know, it rises all the way up to our detection threshold. And so unless nature has been particularly cruel and suddenly turned around this mass distribution, then we expect that there will be many small rocky planets. We're probably just the debris of planet formation. So what do we need in terms of improvement in precision, the instruments that are used

both on orbit and down here on this planet? Is it something like an order of magnitude? Yeah, the technique that both Jeff Marcy and I are using is the Doppler technique, and we're measuring the velocity of stars that are actually tugged around by the planets. And so if you think about our solar system, Jupiter, which is much further away than the Earth, still causes a much larger reflex velocity in the Sun. Jupiter causes the Sun to move around a common center of mass with a speed of about 12 meters per second.

And right now our measurement precision is about 1 to 2 meters per second, which is pretty good. But if you wanted to get down to detecting an Earth, that signature is only 10 centimeters per second. And so we have to go an order of magnitude better in our Doppler precision. That, I guess, is what this project that we're going to spend a good part of our time together talking about, which is FINES, Fiber Optic Improved Next Generation Doppler Search for ExoEarths. And, you know, what would this business be without acronyms that struggle?

That's right. How is FINDs going to help us help you and Jeff to achieve that increased precision you need? Well, we've been struggling for the last several years now, especially in particular the last year, trying to figure out what it is that's sort of keeping us locked in at this limit of one to two meters per second precision. And we've actually, with many, many tests and lots of time at the Keck telescope and other telescopes, realized that it's our inability to measure or to model, rather, what's happening to the light as it goes through our instrument. And so what FINDS is going to do, FINDS is a fiber optic device that's going to actually

take the light as it's coming into our instrument, the spectrograph, and scramble the light so that it goes through our instrument as a very homogeneous, smooth cone of light. And that's not happening right now. Right now what happens is we get a crescent of light that goes through or a ring of light that goes through or all sorts of things are happening and changing the light before it even gets to the spectrometer. So I think with the smooth cone of light that we'll get from the fiber, we're going to be able to model the effects of the instrument on our spectrum

and recover a precision, a Doppler precision, that's better than a meter per second. You know, our hope, our goal is to achieve a half a meter per second precision, and that would match what our colleagues in Switzerland are doing right now. They're doing a little better than us, and they've been using a fiber for a while, and we were concerned about the light losses, but now realize that, you know, this is really key to achieving the sort of precision that's going to get us down to centimeters per second. Is there a little piece of adaptive optical

technology also wrapped up in this? Fiennes also has some adaptive optics, a very clever idea that one of our students who's working in Germany right now thought up. And what he realized is that we're losing a lot of light at the fiber right before it goes in. And so he's come up with a tip-tilt camera that's going to keep the beam of light fixed on the entrance to the fiber. And that's going to increase the throughput of the fiber. And then with the scrambling that naturally occurs inside the fiber, we're going to get the best throughput and the smoothest cone of light. There are a few people who are working on this project right now. Dr. Julian Sprunk is a postdoc who's working with me at San Francisco State,

and he's working on the fiber itself. And Christian Schwab is a graduate student in Heidelberg, and he's working right now as part of the team building some of the largest adaptive optics for ESA, for the European Space Agency, right now, and he's working on the tip-tilt component. That's Debra Fisher, finder of other worlds. She'll tell us more about the ongoing search when Planetary Radio continues. Hey, hey, Bill Nye the Science Guy here. I hope you're enjoying Planetary Radio.

We put a lot of work into this show and all our other great Planetary Society projects. I've been a member since the disco era. Now I'm the Society's Vice President. And you may well ask, why do we go to all this trouble? Simple. We believe in the PB&J. The passion, beauty, and joy of space exploration. You probably do too, or you wouldn't be listening. Of course, you can do more than just listen. You can become

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1-800-9-WORLDS. Planetary Radio listeners who aren't yet members can join and receive a Planetary Radio t-shirt. Members receive the internationally acclaimed Planetary Report magazine. That's planetary.org slash radio. The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan. San Francisco State Astronomy Professor Deborah Fisher has a remarkable record of exoplanet discovery.

It's not that she and Jeff Marcy are tired of finding Jupiter-sized planets, but they'd love to unveil a few that look like our own little world. That's why they want to develop FINES, a fiber-optic system that may sharpen the vision of big telescopes like the Keck instruments in Hawaii. How does this effort fit in with these new tools that we have out there beyond Earth's atmosphere? I'm thinking in particular of Kepler, which I guess you'll be coordinating with. Absolutely. Kepler is going to be, is an incredibly exciting mission. As you know, it just launched on march 6th and

we all watched that glorious takeoff and what kepler will do of course will be a census taker it will find out how many planets there are over an enormous range of planet sizes and what we'll be doing what we'll be contributing is figuring out what the planet mass is. So they'll get the size of the planet relative to its host star and will calculate the planet's mass and therefore its density. And so because we expect quite a watershed of planets to roll off of the Kepler assembly line over the next three years, we want to be geared up and ready to help Kepler to be successful. And to do that, we're going to need to follow up with the very best precision to try and find the planets that are one, two, three Earth masses and complement the Kepler discoveries and really put them on firm footing. So you're going to be trying this out at the Lick Observatory, but is the intent to go on from there to someplace like the Keck?

Absolutely. I think the project will start at Lick Observatory, and I think there may even be a brief time at Lick Observatory with finds when we'll have a precision that may rival what we're getting at Keck. Wow. But the data that we'll accumulate, which hopefully in the very near future, is then going to feed into a design for a similar fiber at Keck. And so we've already been talking to the director, Taft Armadroft at Keck, and the support scientists for the high-res spectrometer. As these kinds of efforts go, at least this initial iteration of finds, it's not hugely expensive, but it's still something that I guess you need some help with, and that's where the Planetary Society has come in. That's right. One of the reasons that it's

so urgent is because we have this opportunity to find nearly Earth-mass planets to support Kepler, and we would go through the traditional proposal processes with the National Science Foundation and NASA, of course, but these tend to be fairly long lead proposals. So we'll submit a proposal. The next round of proposals isn't due until May. They'll be judged next October, and it would be a year later before we would get funding. And we really think this is urgent to be able to support Kepler and to be able to make advances with our regular Doppler search.

And people can read more about this, of course, at planetary.org. Planetary.org slash radio is a good place to look first, and we'll put a link there where you can learn more about the FINDS project. You know, I think the last time I talked to Jeff, we talked about this friendly rivalry between you folks, you and Jeff primarily leading the team here, and the folks over there in Switzerland, the European team. But really still, you and Jeff, I think, have discovered, what, more than half of the planets, exoplanets or extrasolar planets, that we found so far? Right. We've done very well. But I have to say that the Swiss are ahead

of us right now in terms of not so much the number of planets that very well, but I have to say that the Swiss are ahead of us right now. In terms of not so much the number of planets that they've found, but the types of planets. They're really edging down toward finding planets that are now 10 Earth masses and 5 Earth masses. And we're doing that, but we're struggling. And so FINDS is really going to help us to recover that technical advantage that we need to move down to Earth masses. Nothing like a little healthy competition. And yet, here you are at the ground floor of our ability to discover these other planets.

I mean, sometimes I like to describe it and congratulate people like you and Jeff as beginning to fill in the Drake equation. It's got to make you very proud. Oh, it's wonderful. It's the most exciting job in the world, and it consumes my whole life, I'm afraid. Now, you're at San Francisco State. You returned there. You had been there. You went up to UC Berkeley, where Jeff still is. You're still cooperating. But at San Francisco State, I read that you're excited about being able to bring the students in there, bring them into your work. That's right. So this is an unusual university. We have a lot of minority students.

We have a lot of students who are the first people in their families to go to college. And so to give them an opportunity to take part in really forefront research is one of the most satisfying, gratifying parts of my job. And of course, Jeff and I collaborate very closely with the graduate students at Berkeley and with students who are at UC Santa Cruz and really all over. But the students at San Francisco State are here to get a master's degree or a bachelor's degree. And then they're launched into PhD programs. And I have students now at Johns Hopkins and UCLA and University of Washington and University of Arizona, really all over at top programs. And you're one of those success stories too, right? Didn't you get your MS from San Francisco State?

Indeed, that's right. I actually first met Jeff. He was my professor and I was obtaining my master's degree in physics here at San Francisco State. And then I went on to UC Santa Cruz to get my Ph.D. And just as I was finishing up, Paul Butler and Jeff Marcy had this fantastic success of confirming the first detected exoplanet, and I was so excited to be able to come back and join the group as a postdoc in 1997. Heck of a great job.

When we connected, I think we're just printing your boarding passes for a trip to Chile. Are you going to be doing some Southern Hemisphere observing? That's right. In the Southern Hemisphere, I've got my eye on Alpha Centauri A and Alpha Centauri B. Actually, this project is what started us on the path to finds, because for this project, I had to use a fiber. And I'll tell you, we would have pulled it out of the telescope if we could, but there was just no other way. I'm observing AlphaSyn A and B 200 nights this year alone and hoping to observe it

for the next three or four years in an effort to beat down our noise just with brute force of the number of observations that we obtained. But while Jeff and I were in Chile in May on an engineering run for this project, we learned that the fiber gave stability to the instrument that we really never appreciated before. And basically, on the plane coming back from Chile in May 2008, we realized that that's what we had to do at Lick Observatory and ultimately at Keck Observatory as fast as we could.

I got to say, that would be awfully exciting to find some Earth-grade planets on our next-door neighbor system out there at Alpha Centauri. Absolutely, yeah. I'm pretty sure people will think about at least sending little bots to that star system if we're successful. Deborah, thanks again for joining us and happy continued hunting. Thank you. It was a pleasure.

Deborah Fisher is an associate professor of astronomy in the physics and astronomy department at San Francisco State University. She is the longtime colleague collaborator of Jeff Marcy. Together they lead the team that has, as we said, discovered more than half of the exoplanets, planets beyond our own solar system, that have been found so far in our galaxy, with many more to come, we trust. And we'll tell you what else is still to come. That will be Bruce Betts with this week's edition of What's Up, right after we visit with Emily for this week's edition of Q&A. Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, why didn't the Galileo probe return any images of Jupiter's clouds as it descended?

It's easy for members of the public to forget that the Galileo-Jupiter orbiter even carried a probe, because unlike the Huygens probe that descended into Titan's clouds, the Galileo probe didn't return any images. The reason for the lack of images boils down to the problem of how the image data would have gotten back to Earth. There are two main reasons that atmospheric probes can't return very much data. The first is that probes designed to study the atmospheres of giant planets, of Venus, and even Titan, are not expected to survive their descent. There's no opportunity to store lots of data for later transmission, so every last bit of valuable data that they gather must be relayed immediately

back to a receiver, either on a companion spacecraft or back at Earth. Adding to the problem is that since the probes are necessarily small, fairly simple spacecraft designs, they can't be equipped with steerable high-gain antennas, so they have to use omnidirectional or low-gain antennas, which keeps their possible data transmission rates low. The Galileo probe, which had a design based on the Pioneer Venus probes, was designed to transmit only 128 bits of data per second over its hour-long descent, a stream that was shared among seven science instruments. Such a low bitrate couldn't possibly support the relaying of images,

which require kilobits of data even when they're compressed. The Huygens probe, designed more than a decade later, managed a speedy 8 kilobits per second and lasted more than four hours, permitting it to return small and highly compressed images of the scenes beneath Titan's clouds to the waiting Cassini orbiter. Got a question about the universe? Send it to us at planetaryradio at planetary.org. And now here's Matt with more Planetary Radio. Time for What's Up on Planetary Radio. Here's Bruce Betts, the Director of Projects for the Planetary

Society. Fines, we were just talking about with Deborah Fisher. That would be one of your projects, wouldn't it? That would indeed. A fabulous new project. So tell us about the night sky. Well, there are lots of exoplanets out there, but you can't actually see any of them. But there are some nice planets you can see.

Saturn is up there in the east after sunset, high up in the evening sky. In Leo, you can check it out, and if you have a small telescope, you can see the rings, although they're tough to see in a cool kind of way, because they're mostly edge-on right now. And in the pre-dawn skies, where the rest of the action is happening. Venus has transitioned and will start appearing as the really bright star-like object low to the horizon in the east in the pre-dawn. Could be a little tough to see for a while. But Jupiter, a very bright star-like object, not tough to see. Up higher in the east in the pre-dawn and below it, Mars, dimmer, reddish, but still up there. That's the planet roundup for this time around. Let us go to this week in space history.

35 years ago, 1974, Mariner 10 had its first Mercury flyby, our first look up close at any of the Mercury's surface. And, of course, we're seeing more and more of the Mercury's surface these days as Messenger does its flybys. But looking again back in time, 1655, Christian Huygens discovered Titan, moon of Saturn. And now let us go to Random Space Fact. Puccini. Had that mosquito flying around again. Really? I thought you got it before we started recording

It or its friends came back Everybody's a music critic Exactly, exactly He just wanted to participate, I think Exoplanets, let's talk about one of the interesting ones That was discovered recently by the Corot spacecraft Which is in orbit, the European Space Agency spacecraft. And COROT XO7 is the smallest known exoplanet by most measures,

estimated around two Earth masses. But one of those freaky orbits, only a 20-hour orbit around its parent star, so its surface is nasty, nasty hot, enough to make any rock molten in all probability. One of the many weird and exotic exoplanets out there. To learn more, hey, check out the catalog. This is the other reason we need that higher precision that Debra was talking to us about, so we can find one of these guys who's out, you know, a little bit farther in the Goldilocks zone. Right.

Let's go on to the trivia contest. That, too, was about exoplanets. If you go to our catalog or anywhere else where you check out a list of exoplanets, you'll see that they have all sorts of mostly fairly boring letters and numbers for names, and a lot of them start with HD. In this context, what does HD stand for? That was the question. What were the answers, Matt? We got lots of correct answers, and Kevin Hecht, who knew the right answer but also wanted to make sure we didn't confuse it with Harley Davidson. But it turns out that the right answer is Henry

Draper, which just makes me want to go, Henry? Henry Draper? It seems like there was an old radio show that I won't go into, I guess. But that's it. It's the Henry Draper catalog, which is over 200,000 stars. It was Lemuel Lewis, a first-time winner, I believe, in Jackson, Mississippi, who let us know that, sure enough, most of these planets, they're assigned there by the star, and then I guess they assign them a little lowercase letter. That is exactly right. That's the convention for most of these. In this case, the star names, a lot of them came from the Henry Draper catalog, and they're like HDs followed by several numerical digits, depending on where it is in that 200,000 catalog. Based upon the order in which they're found,

they give them a lowercase letter afterwards starting with A, not surprisingly. So, Lemuel, we're going to send you a 2009 year in space calendar and, if you like, a rewards card from Oceanside Photo and Telescope. That's optcorp.com, and that'll get you deals on all things telescopic that they sell out of that place. What do you have for us next time? I can't get enough exoplanets these days, so tell me to win. We're going back to T-shirts by popular demand to win a Planetary Radio T-shirt. Tell me at least three techniques used for discovering exoplanets.

Go to planetary.org slash radio. Find out how to enter. Now, I know about two, but three, that'll be interesting. You've got until Monday, March 30th at 2 p.m. Pacific time to get us your answer. And we have to throw in, because we did something, or I did something, for the first time in almost six and a half years now. We didn't actually give the name of the winner last week. Details.

Chris White. Chris White in Surrey, United Kingdom. He's the one who earned himself a 2009 year in space calendar for letting us know that it was Ceres that was discovered on January 1st, 1801, the first of the main belt asteroids to be found. Now, I think we're done. All right, everybody, go out there, look up the night sky, and think about flashlights and how they light your way. Thank you, and good night. Do you know that I have a thing for flashlights? It's the closest thing I have to a fetish. No, I didn't know, and I really don't think I want to. Well, then again, radios as well.

I probably own more radios than your average bear as well. So you have a lot of flashlights. And a lot of radios. Receivers and transmitters of electromagnetic radiation. Now you're getting me excited. Thank you, and oh gosh, good night. It's Bruce Fetz, the Director of Projects for the Planetary Society, still lighting our way here on What's Up.

Planetary Radio is produced by the Planetary Society in Pasadena, California. Have a great week. Thank you.