Planetary Radio: Space Exploration, Astronomy and Science - Debra Fischer Hunts for a Second Earth at Alpha Centauri

Episode Date: January 28, 2013

Yale Professor of Astronomy Debra Fischer is one of our planet’s most successful discoverers of exoplanets. She has set her sights on Alpha Centauri, where she hopes to find a Earth-sized world in the habitable zone: not too hot, not too cold for life.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Looking for another Earth right next door, this week on Planetary Radio. Welcome to the travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. Deborah Fisher wants to find an Earth-sized planet in the habitable zone around the nearest stars to our own. And she believes she has the right tool to do it. She's back on our show to tell us how. Bill Nye has been meeting strange bedfellows in the capital of the USA. And Bruce Betts will tell us how Mars and Mercury are becoming bedfellows in the sky.

First, though, let's go to the beach with Emily Lakdawalla. Emily, great to talk with you as usual, especially when I think we're going to find entire worlds in a grain of sand. Yeah, I realized when I was talking to some people about the kinds of sediments that Curiosity has been observing on Mars that when I said the word sand, I meant something that people weren't hearing because I'm a geologist and geologists have a very particular definition of what sand means.

It's like the Eskimo words for snow. I saw on one of the charts in your blog, at least five different kinds of sand. That's right. And the reasons that geologists are subdividing sand into all these different kinds with very special size fractions is because sediment behaves differently depending on the size of the grains. The bigger the grain, the harder it is to move in a rushing stream. The smaller the grain, the longer it takes to settle inside a lake. It's very important actually for them to figure out what the size of the grains is that Curiosity is looking at. And the fact that a lot of the rocks that it's looking at has such

coarse grains, things that are larger than grains of sand, they're actually technically called granules, means that it had to have been water that was moving the stuff around. It couldn't have been wind. Unlike, say, at the Opportunity Landing site where most of the stuff is small enough that you actually have to entertain the possibility that everything was windblown, or at least most of it was. So it's actually a very important piece of information. And so you do need to understand what I mean when I say sand. And sand is something that is smaller than two millimeters across. It is a fascinating blog entry with lots of charts and little tables and pyramids of stuff that includes sand.

And I very much recommend reading it at planetary.org. Just look for Emily's blog. And I guess you may have somebody new to introduce there among the blogs, our guest bloggers. Yeah, I'm very excited that we now have Bill Dunford, who's blogged for a long time at a blog called Riding with Robots in the High Frontier. And I had not realized

until I wrote his profile for the website that he is a charter member of the Planetary Society. And he's producing really beautiful photos from data, the same kind of stuff that I like to do. And I'm actually kind of jealous that he gets as much time to do it as he does. Well, something to shoot for. Thank you so much for getting sand in the works today, Emily. You're welcome, Matt.

She is a senior editor for the Planetary Society and our planetary evangelist. Another reason you want to take a look at her blog is to see Emily as a comic strip character. Check that out as well. It's a recent entry. She's also a contributing editor to Sky and Telescope magazine. Here is the CEO of the Planetary Society, Bill Nye the Science Guy. Bill, when last we heard from you, just one week ago, you were hours away from enjoying the inauguration in Washington, D.C., and I know that you went on from there to get some society business done. After the inauguration and some inaugural balls,

I visited Lamar Smith, who is a congressman from Texas. He, of course, is very supportive of space exploration. This is the interesting thing to me, as always, Matt, is people both sides of the aisle are very supportive of space, and especially monetary exploration because everybody realizes what a great value it is. Scientific advancement, scientific understanding and technology, sort of how to say derivative of that work. What we want to do is make flat the new up. Everybody wants budget cuts, but we want to just hold this one steady, not increase it,

just hold it steady. And he also asked me extensively about a mission to Europa and all these exotic, wonderful, distant, distant destinations. So I'm very hopeful that Congressman Smith is going to be able, his awareness is raised, and he's going to be able to help support planetary science. This is the kind of thing that happens, man. I get on the elevator in the Rayburn building, which is the office building for the House of Representatives in the United States. And there's Tim Bergeron, who's the main guy, the chief of staff for Congressman Schiff, who used to represent directly the Jet Propulsion Lab, but now represents the area right by it. And so he has a lot of employees in his district. who used to represent directly the Jet Propulsion Lab, but now represents the area right by it.

And so he has a lot of employees in his district. These guys are, how to say, gung-ho. We want to explore the outer planets. We want to continue to explore Mars. We want to get this wonderful science at a very, I mean, it's a lot of money for you and me, but it's not that much money for the U.S. federal government on this very reasonable price. We're fighting the good fight, Matt. Yeah.

I want to come back to that point that you made, because here are two guys, Adam Schiff and Lamar Smith, who are on very different sides of the aisle and both very much in favor of planetary exploration. That's right. Exactly. It's an interesting thing. Politics doesn't make strange bedfellows. It makes enlightened bedfellows. Ah, right, exactly. It's an interesting thing. Politics doesn't make strange bedfellows, it makes enlightened bedfellows. Ah, I like that. In this case, we'll see where it leads, because it's going to happen in the next couple months. And you know, where NASA goes, a lot of

space exploration around the world goes. Certainly. And people can learn more about this situation, if they care about it, they can visit our site at planetary.org to learn more. Bill, I guess that's it for this week. Thank you, Matt. He's Bill Nye, the CEO of the Planetary Society, Bill Nye the Science Guy, and he does join us each week here on the show. Next up, Deborah Fisher, ace finder of planets elsewhere in our galaxy. Deborah Fisher has been seeking and finding exoplanets ever since she was a student in California.

Now she's a professor of astronomy at Yale University, and she's leading the hunt for what could be the most exciting planet ever, a world the size of our own, that is not too hot, not too cold, spinning in space as it revolves around one of the closest stars to our own solar system. This discovery is going to require an instrument of mind-boggling precision and sensitivity. She's got it. But it's also going to require time on the right telescope in the southern hemisphere. And that's where she could use some help.

Deborah, it is a pleasure to get you back on the show. And also, very exciting to hear about the further developments in your search for exoplanets, extrasolar planets, we used to call them. Thanks for coming back on Planetary Radio. Hi, Matt. Thanks for inviting me again. So you were last on, well, it's been about nine months now, last April. We were talking about what you were headed toward doing. And there have been so many developments in this field since then,

some of them with your own instrumentation. What's happening with this instrument called Chiron? And tell us a little bit about what it is. Yeah, nine months is actually kind of a magical number, right? It's a great gestational period for our instrument. And as it turns out, we finished many upgrades, several upgrades to the instrument in June of 2012, so last summer. And since then, our precision has improved dramatically. We've really learned a lot over the last three years now about what it takes to get extremely high precision in our radial velocity measurements.

And a lot of that is due to the early bootstrap that we got from the Planetary Society for our FINES project, developing fiber optic cables to couple the light into the spectrograph. So our precision now is gorgeous. And when you talk about this precision, your competition there, the other team that also has an excellent instrument is this Swiss team with the instrument called HARPS. About where do you compare with them now? Yeah, I think we're standing toe to toe with them. So I'm expecting that we're going to

take them by surprise this year. They are my dear friends. And so it's a friendly competition, definitely. And they're working with an instrument that costs, I think, about $10 million U.S. dollars. And we're working, we built Chiron for much less than a million dollars. But the upgrades and the different technique that we're using, I think, are allowing us to reach that same level of precision, measurement precision on the stars. precision, you know, measurement precision on the stars. I'm working on a paper and we're now able to measure the motion of a star, let's say like Tau Ceti, which is a bright sun-like star. And we see that our velocity variation over two weeks is less than or about 50 centimeters a second. or about 50 centimeters a second. The nightly precision is 35 centimeters per second. We're not talking in meters per second anymore. So a fraction of a meter per second. But to me, the important thing is that the stability of our measurements over a two-week period

is really phenomenal. So it shows that we're extremely competitive. I think it's the best in the U.S. in terms of the precision that we can get. And we're absolutely chomping at the bit and ready to go. Before we go on, give us a very quick review, a couple of minutes at most, of how this technique works, how you're using these tiny changes in velocity of an entire star to find planets. The Doppler technique that we use measures the velocity of the star, which is changing over time if there's a planet that's tugging it around a common center of mass. This technique is sometimes called the wobble technique because we're measuring the wobble of the star. For a system like Alpha

Centauri, it's pretty complicated because we're measuring, if there's a planet there, we're measuring the wobble of Alpha Centauri A or Alpha Centauri B due to that planet. But those two stars are also orbiting each other with a long orbital period of about 80 years. So we have to measure and account for that motion as well. We're looking at the spectrum of the lines. And a spectral line is a feature, like for example, an iron absorption feature or a hydrogen absorption feature in the star, because those atoms are there in the atmosphere of the star. And they absorb light. And those absorption features, which in the spectrum of the star span four or five pixels, we measure the change in the shift of those lines with a precision now that's about one ten thousandth of a pixel. So it's quite remarkable.

Getting down to measuring Doppler shifts of stellar absorption lines that correspond to tens of silicon atoms in the CCD detectors. So we're not going to be able to probably do much better than that. So there may be a physical limit on this, at least in using this technique. But it certainly is capable of enabling us to discover exoplanets throughout our region of the galaxy. As we're learning from Kepler, I mean, you must be very excited also about the tremendous success of that spacecraft that is turning out thousands of exoplanet candidates. Absolutely. What an amazing instrument and what an amazing project that has been. You have to go and look at Bill Beruki who pushed this thing through at a time when nobody believed that CalPLA would work. And look at what it's doing now. It's so exciting.

It's giving validation to the effort that we're doing. We now are in a position where we know the planets are actually there and our job is to find them. And so having that confidence makes a big difference in our determination, I think. You know, there's not a shred of doubt in our mind that the planets are there and we just have to work better and harder to find them. So is it safe to say now that planets, rather than being the exception, as was once suspected by some astronomers, that planets are more the rule around stars. Absolutely. And, you know, the science fiction stories told us this. We all

believed it as little kids. But then when we became scientists, we had to say, well, if we don't have evidence, then we have to be careful about assuming that anything is there. That's the right thing to do. And then now we've gradually gotten to the point where the Kepler mission tells us that, you know, most stars have planets. Most stars have planets. You have to, there has to be something going on in the formation phase to get rid of the protoplanetary disks and get rid of the planets. We can imagine some exceptions where that'll happen, but the rule is when stars are born, they form with a host of planets. Planet finder Deborah Fisher will return in a minute. This is Planetary

Radio. Hi, this is Deborah Fisher. I'm an astronomer at Yale University, and we're searching for Earth-like planets in the Alpha Centauri system, the closest star system to our own. This would be an incredible discovery, and the Planetary Society wants to help my team continue the search by helping us buy time on the Great Telescope at Cerro Tololo in Chile. But to do this, the Society needs your support. Your gift will enable us to reach our goal, 20 full nights of observation. Please visit planetary.org slash exo to learn more. That's planetary.org slash EXO. Thanks so much. Hi, this is Emily Lakdawalla of the Planetary Society. We've spent the last year creating an

informative, exciting, and beautiful new website. Your place in space is now open for business. You'll find a whole new look with lots of images, great stories, my popular blog, and new blogs from my colleagues and expert guests. And as the world becomes more social, we are too, giving you the opportunity to join in through Facebook, Google+, Twitter, and much more. It's all at planetary.org. I hope you'll check it out. Welcome back to Planetary Radio. I'm Matt Kaplan.

Deborah Fisher has returned to our show. She's the Yale University professor of astronomy who leads one of the most successful exoplanet discovery teams in the world. She has seen us go from wondering if there are planets circling other stars to knowing that planets are everywhere in the galaxy, one of the most exciting developments in astronomy. And perhaps most exciting are these handful of roughly Earth-sized planets that have been found

that are in this so-called habitable, the Goldilocks zone. Unfortunately, that doesn't include the one that the Swiss team found in the Alpha Centauri system, does it? That's right. So the planet that the Geneva team found orbiting Alpha Centauri was, of course, it was heartbreaking to me. It still is an extremely difficult detection and it requires confirmation and that's what we're going to be doing in the spring the orbit of this planet is 3.24 days which makes it a roaster you know you'd have to be you'd have to have asbestos people living on the planet to survive so um the one thing we know from the Kepler project is that when stars, when we find one rocky

planet, they tend to come in multiplets. So Alpha Sun B and probably Alpha Sun A have other rocky planets in their systems. And knowing that that one planet is there, again, just gives us more confidence and more determination to find the other ones. Well, I'm really pleased to hear this confidence that you're stating that with. I mean, you seem to be pretty convinced that they're out there waiting for us to discover them. Yep. You know, it's an evolution because four years ago when I submitted my first proposal to the National Science Foundation, just coincidentally, there was a theorist who submitted a paper saying,

planet formation around Alpha Cent A, impossible. Around Alpha Cent B, impossible. The theorist would then privately tell me, don't really listen to us, because you guys are the ones who tell us what's there and help us refine our theory. But, you know, we were swimming against the stream, definitely. That whether there would be planets in binary star But, you know, we were swimming against the stream, definitely, that whether there would be planets in binary star systems, you know, is still a very open question. And now we see that that they're there. All right. So what is it that you need now? You've got the instrument,

you know what telescope you want to use. What's missing to allow you to continue this search? What's missing to allow you to continue this search? It's actually time. Even though our precision is as good, I think, as we can do with this instrument and as good as probably the Geneva team can do with their instrument, what we need to do is map out the orbit, and we need many, many orbits to sort of beat down the single measurement precision. When we're talking about finding an Earth-like planet, it's going to be in an orbit that's anywhere from several months to a year or a bit more.

And so that means that we've really just got to observe these stars intensely over a long time span. So we have funding from NASA to develop our instruments, which is fantastic. And we have funding from NASA to develop our instruments, which is fantastic. And we have funding from the National Science Foundation, which originally provided the support to build Chiron, the best spectrometer, certainly in the US. And so we've got a lot of support for the instrumentation effort. And the problem is that NASA doesn't really invest in ground-based telescopes. They invest in space-based efforts and or in projects that can contribute to the science for their space-based missions. So we're just having trouble actually putting together the telescope time that we need. It's available to purchase

on Chiron at the Cerro Tololo Observatory. And so that's what we've been doing for the past few years. But it's always a tight budget to do that. So Cerro Tololo, that's one of the observatories down in Chile where the observing is so good down there in the southern hemisphere. What does it cost? What does it actually run you? Is it a per hour charge? Well, we purchase time by night, by the night. And we have several objects that we're looking at in addition to Alpha Centauri,

very bright stars where we're also trying to find Earth-like planets at habitable zone distances. All the stars are nearby. None as close as Alpha Centauri, though. And the cost is $1,600 a night. Seems like a bargain. It's not bad. I mean, compared to Keck, of course, which is nearly $100,000 a night to run that telescope. But this telescope at Cerro Tololo is apparently quite adequate for you to continue the search.

Yeah, because we're looking at bright stars and because it has the instrument that we want to use. And furthermore, Alpha Centauri, of course, is a southern hemisphere star, so we have to be in the southern hemisphere to observe that. Well, Debra, of course, the Planetary Society hopes to continue to help you with this search. People can learn more about this on our website. We'll put the link up where this show can be heard, and you can get there from planetary.org slash radio. You can learn more about Deborah's search, ongoing search for not just an Earth-like planet at Alpha Centauri, but elsewhere in our region of the galaxy. Deborah, this is so exciting. I look forward to talking to you again, and hopefully when that happens,

maybe we'll even have a planet or two to talk to you about in that nearby system. I think so. I hope so, yes. We're going to do it. Debra Fisher is an astronomer and professor of astronomy at Yale University. We've been talking to her on and off for years, something that I look forward to continuing here on Planetary Radio. Up next, yet another astronomer, the one we talk to every week. That's Bruce Betts with this week's edition of What's Up. Time for What's Up on Planetary Radio. Here's Bruce Betts, the director of projects for the Planetary Society, to tell us what's up in the night sky. And eventually we will give away to some lucky person Bill Nye's voice on their answering machine. Hi.

Hello. Mercury is very low in the west after sunset in the evening sky, as opposed to sunset in the morning sky, which occurs only rarely. And watch for it passing really—that was a joke, you see. Yeah, I get it now. Anyway, Mars is very low in the west as well. It was a bad joke. And the two of them on February 8th will be only 0.3 degrees apart. So super close in the sky, Mercury looking whitish and Mars looking reddish.

But it's going to be tricky. You've got to get a clear view to the western horizon and pick it up as soon in twilight as you can, but kind of cool. Then Mars will keep getting lower and really impossible to see. Mercury will get higher through mid-February and then start dipping away. We've always got Jupiter really easy to see, the super bright object over there in the east or southeast early evening. Saturn also coming up a little bit later. Now I want to mention, and we're going to have more, you're going to have more, I'm going to have more about this, but an asteroid 2012 DA14 will be flying by Earth closer than our geosynchronous satellites on February 15th. It will be not naked eye visible, but if you live in places like Europe, Asia, and Africa

and are really into this and have steady binoculars or a small telescope, you should be able to see it. We'll give you more details both on our website and on our show in the next week or so, but that's coming up February 15th. Absolutely. And we'll have some special stuff going on here on the radio show and elsewhere. Also keep track, of course, at planetary.org. All right, this week in space history.

Unfortunately, this was the week in 1986 that the Challenger space shuttle exploded, killing all of those astronauts. And also during this week in 2003 when Columbia broke up during reentry, killing all seven of those astronauts. On the much, much happier side of things, it was also this week in 1958 that Explorer 1 became the first U.S. spacecraft, U.S. orbiting satellite. Decidedly mixed results this week in history. Now we move on to random space fact. That was quite majestic. Did you know, Matt, in 1900, there was only one known near-Earth asteroid?

And here I'm using the formal definition of near-Earth asteroid, asteroid that comes within 1.3 AU, or Earth-Sun distance, of the Sun. And that was the asteroid Eros, 433 Eros, that was discovered only two years before in 1898 and explored more recently by Shoemaker-Nier spacecraft. There are now more than 9,500 known to be hanging out in our part of space. We've come a long ways, of course, so have the asteroids. We move on to the trivia contest. And I asked you, what is the approximate ratio of the escape

velocities of Jupiter and Earth? So how much higher in a ratio sense is the escape velocity from the top of Jupiter's atmosphere than it is from the Earth's surface. How'd we do, Matt? What's most interesting to me, of course, is the behind-the-scenes stuff here. This is the first contest where we had people entering on our new online form. And we got a lot of great responses. And because there is a field there that actually tells people, hey, tell us what you think. What do you want to tell us about Planetary Radio?

We got a lot more comments than usual. Lots of very nice things that people had to say about the show. Thanks for a fantastic radio show, said Anders Lundberg. He says, I listen to it every Wednesday, taking my half-hour stroll through the forest to work. That's how I want to get to work. stroll through the forest to work. That's how I want to get to work. I love this one from Maiv, and I'm probably not pronouncing that correctly.

Maiv Hamrick in Felton, California. Woot, we can has web forms. Not everyone was thrilled with the form. Ed Lupin in San Diego. He said, by an odd coincidence, the winning ratio, this ratio is exactly how much harder I found it to use this new method of submitting an answer versus email. Our winner this week is Eric Valdi of Minneapolis, Minnesota, who said it's 5.32, Jupiter being 59.5 kilometers per second and Earth at 11.19. And that does indeed, I think, come out to 5.32, right? Indeed it does.

Eric, you have won Bill Nye's voice on your answering machine, and I will be in touch. I've got to read you one more. Mark Wilson, he said, The ratio of information someone gets by listening to planetary radio compared to any other program is astronomical. Thanks, Mark. We move on to the new trivia contest, reference back to the random space fact. I mentioned Eros as the second largest near-Earth asteroid. So of course now I'm asking you, what is the largest known near-Earth asteroid? Again, defined as asteroid.

Asteroids coming within 1.3 AU of the sun. The entry form is new and improved. They can now go to planetary.org slash radio contest. Planetary.org slash radio contest, one word. You can also find that link where this show is listed. You get there from planetary.org slash radio. And they'll want to get us that entry the usual time, 2 p.m. on Monday, February 4th, 2 p.m. Pacific time. Now, you've got one more thing to tell us about.

I do. I am once again teaching an online introduction to astronomy and planetary science class through California State University, Dominguez Hills, and it'll be starting Wednesday afternoon, February 6th. And we'll get some detailed information up on our website in the next few days. We've got last year's class, same class, archived, which you can find on our website under Multimedia Videos. But now we'll be doing it all over again, but with updated information. And if you want to tune into the live feeds,

you can actually ask questions during the classes, hour and a half classes every Wednesday for the next several weeks starting February 6th. I'll get you more information on the website and mention it again next week. So Bruce, an outstanding online learning opportunity like this, running over an entire semester, why this must cost hundreds, if not thousands of dollars.

Why it does, but not to take the class. That's free. Would you believe it? Free. Now, only a subset of students actually get college credit for it, but it is free to take the class. I'll even feed you midterms and finals and reading assignments to make you feel warm and fuzzy if you like such things. Gosh, oh, golly, a final. I can't wait.

But you can also just watch and enjoy the classes, either live as they're happening, which will be Wednesdays at 3 p.m. Pacific time, or you can just check out the archive classes. It's a great class. Thank you very much. I'll talk to you next week. All right, everybody. Go out there.

Look up at the night sky and think about tails and why we don't have them. Thank you, and good night. He's Bruce Betts, the director of projects for the Planetary Society. He joins us every week here for What's Up? And there hangs quite a tale. Planetary Radio is produced by the Planetary Society in Pasadena, California and is made possible by a grant from the Kenneth T. and Eileen L. Norris Foundation and by the proud members of the Planetary Society.

Clear skies.