Planetary Radio: Space Exploration, Astronomy and Science - William Borucki on Kepler's Search for Another Earth

Episode Date: January 18, 2010

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Kepler finds its first five planets, 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. After just ten months in space, the Kepler telescope has already found five new worlds and is well on its way to the hope for discovery of planets like our own. Principal Investigator Bill Berucki returns to our microphones with a progress report. Then, is it an asteroid or a burned out rocket stage? Either way, it made a run at the Earth a few days ago. Emily Lakdawalla will tell us more.

Bill Nye calls in from LaGuardia Airport with evidence that there may be plenty of solar systems like ours out there in the Milky Way. And we'll enjoy a lovely winter's day in Pasadena with Bruce Betts as we hear about the night sky and get another space trivia contest underway. A diamond in the rough, or rather a diamond in the void, the European Space Agency's Rosetta spacecraft, still on its way to rendezvous with a comet in 2014, encountered an asteroid called 2867 Steins.

You'll know what I mean by a diamond when you check out the beautiful animation of this flyby that has just been released by ESA. The animation and a nice article by Emily are at planetary.org. If you're hearing this early in the week, you still have time to send birthday greetings to the second human to walk on the moon. Buzz Aldrin turns 80 soon, and the Planetary Society is

throwing him a party. We hope you'll join in. Time to check in with the Society's Science and Technology Coordinator. Emily Lakdawalla is also mistress of the Planetary Society blog that so many of us faithfully follow. She always brings us her hand-picked selection of the best stories she has covered in the last week. Emily, mysterious near-Earth objects, or object, I guess, but first of all, just a few seconds, current status up there on Mars? Well, JPL issued a release to my shock last night that they are actually, it's really come to this, they're actually going to use the arm on the rover to do a little bit of, quote, sculpting, unquote, of the soil in front of one of the wheels, I presume the left front wheel, to try and see if that can help get the rover out.

But it's not looking good for Spirit at this point. It's a shame there isn't a two-by-four or something that they could grab and stick underneath the wheel there. Or just rocks, but there aren't even any of those around. Well, we will mention that in two weeks, we will have an update from inside JPL on both of the rovers. But now, this object, which got people very excited and was just discovered when? It was just discovered a few days before it passed by, but that's actually pretty common for small near-Earth objects. It got people very excited because it was relatively bright, magnitude 14, not so difficult for a lot of amateur astronomers to take a look at. And it

was passing very close by Earth within one third of a lunar distance away from Earth. So it's nice and close, nice and fast, a good challenge for observers. But now there's some debate over whether it's a natural object or a manmade object. The debate's gone back and forth. People assumed that because it had a one year period,, it must be man-made. Then NASA came out with a release saying, well, in fact, if you look at its orbit, it goes in as far as Venus and out as far as Mars. So that's not so likely to be man-made. But then an ESA analyst came in and said, now, wait a minute, I've done some math. And I think this might be the forgot upper stage for the Venus Express Venus orbiter. So that would obviously explain why it goes inward as far as Venus.

How strange. But there's been some criticism of his conclusion as well. Yeah, someone has pointed out that he used outdated orbital information for his work, and I have no idea how much that affects his results. But it's been an interesting debate. Fortunately, there is a way to resolve this debate. The gigantic Goldstone radio telescope did get some time on this object. And once they analyze the results, they should be able to determine whether it's made of metal or made of rock. And that'll settle that debate. And when you say they got some time, that's because they're using it as a radar instrument. That's right. It's used both for deep space communications and for radio astronomy.

And as such, its time is subscribed very far in advance. So they had to ask the guy who had the time at that time for permission to give up some of his time to this short time study of a near-Earth object. Something we've talked about in the past in this show and probably should again someday soon. Absolutely. Emily, thanks again. Great report. You're welcome, Matt. Talk to you again next week. Back with Bill Barucki, the principal investigator for the Kepler mission,

right after we hear from Bill. Hey, Bill Nye, the planetary guy, I'm in transit. And this week, what's the big fun? Well, it's micro fun. The microlensing follow-up network. These are a group of people using telescopes in the southern hemisphere between May and September to observe the galactic bulge of the Milky Way galaxy. And when they do this, they detect what we strongly believe are other solar systems, solar systems beyond ours. Now, they say that only about 15% of the stars in the Milky Way have solar systems similar to ours. It's not very many.

Fifteen percent of 400 million. That's 60 million solar systems that might be like ours, and they might have Earth-like planets. Talk about science fiction and communicating with other civilizations. It's astonishing. Sixty million opportunities. My friends, all you've got to do is go to the Southern Hemisphere with extraordinary telescopes and get the gravity of crossing stars to help us observe light being bent from the galactic bulbs. What could be simpler? These are discoveries that could change the world.

Well, I've got to fly, and today it's literally Bill Nye the Planetary God. When we last talked to William Berucki, his spacecraft had just settled into a long orbit around our sun and had turned a steady eye on about 150,000 stars. Bill is the principal investigator for Kepler. He and his colleagues announced a couple of weeks ago that the probe has already discovered a nice selection of new exoplanets, world-circling distant stars. But Kepler is just getting started. When I talked to Bill a few days ago, he mentioned that ground telescopes are already attempting to confirm scores of additional exoplanet candidates.

This remarkable success is proof of the so-called transit photometry technique first suggested by Bill decades ago. He has been with NASA's Ames Research Center in Northern California for more than 45 years and first worked on the development of the heat shield used by the Apollo moon missions. Bill also did pioneering work on threats to Earth's protective ozone layer, but now his attention is on the search for other Earths. Bill, welcome back to Planetary Radio. When we last talked in May, you had a very good start for the Kepler mission and a lot of optimism,

and now you've got five nice, big, fat planets under your belt. Actually, one of them is a smaller planet, which is even more interesting, because it's Neptune-sized, which is quite a bit smaller than Jupiter-sized. So it's been an excellent period for us making discoveries and confirming those discoveries, because it's both. You have to make the discovery with photometry, you have to confirm it with radio velocity or with some other method. And it's really astounding that we're able so early to find a small planet as well, a small planet being a Neptune-sized planet.

And I'm going to suggest that people visit your website right up front. It is, of course, kepler.nasa.gov, and we'll have a link to that at planetary.org slash radio as well, because that's where, among other things, people can see a comparison of these five, well, hot Jupiters, although four of them are much larger. And yes, that one is clearly a good deal smaller, but still a good deal bigger than Earth-sized,

which is your primary goal, I think. That's right. Clearly what we want to do is find Earth-sized planets, and even more than that, we want to find out if they're common in the habitable zone, where conditions would be right for life. And so it's two steps. Find small planets and find them in the habitable zone,

because we certainly expect to find small planets in the short-per period orbits where they'll be very hot and not suitable for life. So it's one step at a time. Find the Jupiters, that's the easiest. Find Neptunes, that's the next hardest. And we keep on moving and developing our capabilities until we get to the point where we find Earth-sized planets, we find them in the habitable zone, and we find them in enough numbers so we know how frequent they are. Are they common in a galaxy or very rare?

And to do that, you need to be able to find many rather than just a few. My favorite illustration on the website is a really nice chart that plots orbital distance against Earth masses for exoplanets. And if you look carefully, there's this narrow green bar, which is that habitable zone, the little Goldilocks just-right zone, and lots of little dots all over the chart, but only one so far, and that's where we live. That's right. And that's the area that we're going to try to fill in in the coming years. But one has to recognize we do this one step at a time.

So in the coming year, we expect to find some of the smaller planets, some of the longer period orbits so they're further away from their star and a bit cooler. But to see three transits, and that's the minimum number you need, for a planet in a habitable zone of a star like our sun, it means you have to wait three years. We've only launched less than a year ago, so we've still got a couple more years before we'll be able to tell you our Earth's inhabitable zone frequency. We may find Earth with shorter period orbits, and it's conceivable we could find an Earth

inhabitable zone of a tiny star that's very cool, but they're hard to see, and it's not obvious that we'll be able to find those at all. You started work on this technique of finding planets. You wrote the paper, boy, it's almost 26 years ago now, 1984. And could you go through once again with us, as you did last May, just a little thumbnail description of how you're able to use these tiny changes in the light of a star to find other worlds. Sure. When we talk about trying to find planets, logically what you'd expect is you take a big telescope, you look at the star, you see the planets. That, by far, is the hardest way of doing it because the star is so bright. So what people have been doing is

instead they look at the characteristics of the star itself, because those are changed by a planet. There's the wobble method where the star wobbles around because the planet's going around. There's our method, which is the transit method, where brightness of the star changes because the planet moves in front of it and blocks some light. That's what we use, and it's by far the most sensitive to small planets. So we can find planets, or should be able to find planets as small as the Earth. And in fact, we found signals, not from planets, but signals from stars that are that small. So we know

it works. It's a matter of spending the time to develop photometry, to measure small changes, putting that together as an instrument on a spacecraft, getting the funding, building this, testing it, and then launching it. Of course, we launched in March, and so we've been making observations for

about six months now. It takes a few months, of course, to qualify the spacecraft to make sure all the right switches are turned and the system is functioning properly. What is it about Kepler that makes it so uniquely well-suited for this job? Kepler is special in several ways. By far the most important way is it has the sensitivity to find these very small signal changes. So it has to have very high precision, very low noise. On the other hand, since we don't know which star might have such planets, and even if the star has planets, if the planet is not lined up with your line of sight,

so it blocks some light, we wouldn't see the planet. So we have to have the ability to look at many thousands of stars simultaneously to see those that do have planets and those that do have the orbits lined up properly. Right now, we're looking at over 150,000 stars, and we're expecting to see several thousand of those stars show us the possibility of planets. We don't know which will have planets, so you look at them all. You have, I assume, sophisticated computers that are helping you to compare these images and say, oh, look at that one up there in the corner.

That one has just lost a little bit of its brightness. That's right. We have a cluster of computers. They're not that different than what people have as home computers, but they're as powerful as you can get a sort of a home computer. Fifty of these.

And they work together looking through all these 150,000 stars, looking for these dimmings, and seeing if that repeats. So you really are saying, did it repeat two or three times? If it repeated three times, you'd measure the orbital period twice, and those things should agree, one with another two apart per 100,000.

So basically, it's a lot of modest-sized computers working together, checking each and every star, each and every half hour to see if it's changed its brightness, and if so, seeing if you can then associate an orbital period. I'll be right back with more from Kepler Mission Principal Investigator Bill Barucki. 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 Society at our website, planetary.org slash radio, or by calling 1-800-9-WORLDS. Planetary Radio listeners who aren't yet members can join and receive a Planetary Radio t-shirt.

Our nearly 100,000 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. William Barucki and the rest of the Kepler mission team are celebrating their confirmed discovery of five exoplanets. But their search for another world like our own is still underway. Bill is principal investigator for this spacecraft

with an exquisitely sensitive CCD camera that stares at 150,000 stars, watching for minute changes in their brightness. When Kepler sees that momentary dimming at least three times, Bill knows it may have found yet another planet. Once you've done that, you're only halfway there. This says there's a candidate planet at this star, at this period, with this kind of size. But it turns out that there are other things that can mimic this kind of signature.

For example, if you have a target star, and behind the target star nearby is another eclipsing binary star, two stars eclipsing one another, that dimmer star's light is mixed in with a brighter star, and it looks like it's a tiny planet instead of one star eclipsing another, or if one star grazes another. So what we have to do is we go to the ground-based telescopes,

the big telescopes and the Canary Islands and University of Texas, the Javi-Eberly telescope, the Keck telescope in Hawaii, and we use these telescopes to tell, is the object a star or a planet? They can tell whether it's a star immediately because it's so massive. And the biggest telescopes can actually measure the mass if it's a planet if that planet with the ground-based telescope says yes indeed we have the same order of period the same phase that matches the discovery then we say we have a confirmation we can announce it to the public and we'll be sure that we're telling them what's correct and not misleading people we want to be careful that we don't get so eager to announce things that we make mistakes.

So we spend a great deal of time, many months, looking to make sure what we tell the public is really correct. We have about 150 candidates. That is signals that look like they might be planets. Of those 150, we have only been able to search 30 or 40 of these and find a confirmation. And so in the coming years, we'll be looking through over another 100, and we have new data. We have another seven months of data that have come from the spacecraft, in addition to the first few weeks of data that gave us our first five planet discoveries.

So we expect to find many more in the coming year. We'll be very busy as we look at all these possibilities with our telescopes to see what else we can announce. And we'll be emphasizing now, now that we've found some of the bigger ones, doing more work to find some of the smaller and cooler ones. How is the health of the spacecraft? I saw a story about some trouble you were having with a small number of the many amplifiers that work in tandem with this amazing almost 95 million pixel CCD that you have on the spacecraft.

That's right. First of all, all the channels work well. There are two or three that aren't quite as good as the rest, but they all look like they're going to do a good job for us. The other aspect that we have is every so often a galactic cosmic ray, an energetic particle that's flying through space, strikes the electronics. The electronics immediately says something is wrong here and safes the spacecraft. So the spacecraft points the solar panel directly at the sun and slowly rotates about that axis and tells us that we need to check it and make sure that it's fine. And so we call it

up, check its electronics, and tell it to go back to work. So that happens every few months as well. And you know, we've talked with people on other missions, and it's almost as if these so-called safing events are almost a rite of passage for spacecraft in our solar system. That's true, because our entire solar system, of course, has galactic cosmic rays pouring through it, energetic particles from the sun. But Kepler is in an especially good position in that it's well away from the Earth's radiation belts. Because it orbits the sun and not the Earth,

it's a long way from the Earth. It's completely out of the Earth's radiation belt. So this happens much less often to us than to other spacecraft. What will happen when Kepler confirms, in conjunction with the confirmation from these ground instruments that you talked about, when it discovers a planet much like our own, orbiting about that far away from a star, in that zone where there could very well be liquid water on that new world. I think everybody will be very, very excited. It will be a wonderful step forward in our exploration of the galaxy for life.

But we're still not going to be satisfied. We're going to say, well, great, we found one or two or five of these planets, but do they have an atmosphere? Is there life on them? And so our mission will be succeeded by ever more powerful missions. A mission that might fly after us called Terrestrial Planet Finder could go and make the measurements and see if the atmospheres of these planets have gases in them like water vapor, like in our atmosphere, or CO2, again, like in our atmosphere. And even better, do they have oxygen. So that would be another kind of mission that would succeed ours.

There's also a mission that people are trying to get funding for called CIM. And what it's designed to do is to look at all the nearby stars and see how many of those have planets. It's a much more difficult experiment than our own because our own stares out into one area of space, not all of the space, but just one area, and looks at a huge number of stars to find out, are Earth's frequent or are they rare?

If they are frequent, then modest-sized telescopes can be launched to find out more about these planets. If they're rare, then you have to have very expensive, very large systems built and launched, because they'll have to look at a very long distance to find enough targets to find Earth. So the result of our experiment will tell us how to proceed. Finding Earth is the first step, but it's not the only step. And once we find gases in the atmospheres of these planets, oxygen, we still won't be satisfied. We'll want a more powerful mission that, I don't know, might go there, for example, with a television camera and show us what's to be found. An exciting future with a very

exciting start. Once again, Bill, congratulations on this tremendous success, very early success for the Kepler mission. Thank you. I hope to talk with you and your audience again about what we find in the coming years. We look forward to that. I hope we can make this a regular occurrence. Bill Berucki is the principal investigator at NASA Ames Research Center for the Kepler mission, which uses a technique that he basically wrote the book on almost 26 years ago for finding exoplanets, and it has already found five of those in its very early period of operation.

Planetary Radio will continue in just a moment when Bruce Betts drops in. That'll be for this week's edition of What's Up, just a few seconds away. What a lovely setting for this week's edition of What's Up with the Planetary Society's Director of Projects, Bruce Betts. We're sitting at the foot of Green Street, and they're still cleaning up after the Rose Parade. They are, weeks later. Well, I don't know about cleaning up. They're still taking down all the mini grandstands they install. I almost ran over some on the way here.

You're supposed to drive on the street. I never do during the parade. It's a really beautiful day here. And if you look off through the trees there, up there is Mount Wilson and the solar telescope. And, I mean, once upon a time, if he'd been standing on the edge, we could have waved to Edwin Hubble. Wow, and he could have totally not seen us. That's right. And we could have not been able to call him with our cell phones.

Well, what can we see in the night sky? Oh, well, you can see good stuff. There's Mars, Mars opposition coming up end of this month. Mars getting brighter and brighter, looking like a bright reddish star, rising a little after sunset and then pretty much around sunset at its opposition. It will appear in the east, low in the east, and if you flip your head to the other side of the sky without hurting yourself, you'll see Jupiter still low in the west, looking like a super bright star.

We'll see Jupiter still low in the west, looking like a super bright star. And we also have Saturn rising later in the evening in the east and up high in the south in the pre-dawn. Did I mention what a beautiful day it is here today? With apologies to those of you who are going through a genuine winter. Well, yeah, I mean, the birds are singing and the sun's shining, but in my shorts I'm sitting in three feet of snow. Let's go on to this week in space history. In 1986, Uranus, Voyager 2, flew by. The only flyby ever of Uranus by a spacecraft occurred this week.

Cool, huh? And you know what else happened this week? 2006, New Horizons launched on its way to Pluto. Four years. We're four years in. I'm going to let you do all the arithmetic now. Which leads us to a related random space fact. Feel that mountain air.

Exhilarating. New Horizons just a couple weeks ago reached its halfway point in distance and it's way out, tootling out to Pluto. Wow, so it's all downhill from here. Yeah, that's how the solar system works. Yes. All right, trivia. On to trivia. We asked you how long is the International Space Station? Turns out NASA has some different views than others. So I'm willing to take length or width, however you define them. I just wanted the basic dimensions. How did we do, Matt? Well, we got both.

And NASA does define a lesser dimension of the International Space Station as the length. Most people would call it the width. It happens to be, as we were told by, and I'm going to mangle this, Paweł Wartowski of, can you say that? Malopolska, Poland is our winner this week. He went with the NASA definition of 73 meters or about 240 feet. That's from the PMA-2 to the ZWED module at the other end. Although, if you measure the truly long way, it's more like 108 meters. But, you know, we won't do that. We would have accepted either one. But, Pavel, you're our winner

this week, and he is the first winner of William Hartman's book. Cool. Autographed, even. Traveler's Guide to Mars. Nice book. Do we get any weird units? Oh, man, we got tons of weird units. I love a lot of these, and I had to collect some of them, as you know. One of my favorites, BFLs, Babelfish Lengths. You would love that. I'll just read some to you. 243 light nanoseconds, 0.798 football fields. Of course, one ISS length.

We got that from several people. Is that 1.000 if you go to more digits? A bit over one-sixth the length of the Battlestar Galactica. Oh, that's the coolest. Well, I don't know. How about 31 Mercury capsules? Also cool. Or if you really want a 4x4 22.3 Jeep liberties

okay thank you from our Jeep dealer yes lots of wonderful units as you can tell and we thank all of you we are always entertained by your creativity in this funny you'd mention units because I was thinking units for the next trivia contest

flashback to some of my research of the old days there's something in planetary science that's used to describe, that's a parameter that falls out of the equations of how quickly something heats up or cools down, like a planetary surface under periodic heating. It's called thermal inertia, because it's kind of a resistance to heating and cooling.

What are the units of thermal inertia? Because they are truly weird, that it would tie to anything physical, much less be able to be a good descriptor of planetary surfaces. You can give it in the standard metric units, or you can use the old style that was a Kluge system, sometimes called Kiefer's after one of the pioneers in planetary science, that mixes it up but gives nice units. But this one will be tough to convert to any normal Jeep units. This is Kiefer Sutherland before he went into acting.

Yes, yes, that's exactly it. The weird thing was when he was doing planetary research, every surface was 24 Kiefers. Good one. Okay, so you have until the 25th of January, 2010, to get us this answer and tell them how to reach us. We need it now, Chloe, and we need it at planetary.org slash radio. That's it. I think we're done.

All right, everybody, go out, look up in the night sky, and think about undulations. We're sitting near some that are oddly called bumps here in this backwards area. Old sidewalks here, old sidewalks and old streets in a beautiful part of old Pasadena. He's Bruce Betts, the director of projects for the Planetary Society. He joins us every week, and this week on a beautiful winter day in Pasadena, California, for What's Up. Why do galaxies look the way they do? You'll be surprised by the just-discovered answer.

That's next week on Planetary Radio, which is produced by the Planetary Society in Pasadena, California. Keep looking up. Редактор субтитров А.Семкин Корректор А.Егорова