Planetary Radio: Space Exploration, Astronomy and Science - Elisa Quintana on the Discovery of Earth 2.0

Episode Date: June 24, 2014

Kepler-186f is the very first exoplanet that is both the size of our own world and in the habitable zone surrounding its star. SETI Institute scientist Elisa Quintana is lead author of the paper announcing its existence.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

The lead discoverer of Earth 2.0, 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. Elisa Quintana is the young researcher whose name was at the top of the paper announcing discovery of Kepler-186f, the first Earth-sized exoplanet found in its star's habitable zone. She joins us on today's show. Bill Nye revisits one of the biggest science stories of the year with a lesson about how science works. And I'll congratulate Bruce Betts on

the announcement by NASA that the Planetary Society's Living Interplanetary Flight Experiment, or LIFE, will be studied for the Asteroid Redirect Mission. We begin by accompanying Emily Lakdawalla on a literary trip to Mars. Emily, it's not quite enough to fill an entire bookshelf, but there sure are a lot of books coming out about the Curiosity mission, the Mars Science Laboratory. You've got a review of one of these in your entry in the blog for June 20th. And it features a book co-written by one of my favorite Martians. That's right. It's Rob Manning, who is an engineer at JPL. He's been the chief engineer for the Mars program at JPL, but this book is really focused on his stint as chief engineer

for the Mars Curiosity rover mission. And let me tell you, does he have some very candid and occasionally shocking stories to tell about the development of this mission? Give us an example of one of those. And you said you actually did find one story about gravity someplace else, but it probably wasn't told the way Rob tells it in this book. No, definitely not. So the story that I mentioned in my blog post is one where they discovered after the landing that their landing simulations were very, very sensitive to tiny changes in the force of gravity. And you would think,

why? The force of gravity doesn't change. It's constant for a planet. Well, yes, but the force of gravity does vary a little bit from place to place, depending on topography and what kind of rocks are underground. There was a whole mission to the moon called GRAIL that studied in detail the gravity field, and that helps a lot with spacecraft navigation. We don't have that at Mars, and they found out later just how sensitive the Curiosity landing system was to the force of gravity. If it had been off by just a tenth of a percent more, they may well have run out of fuel and crashed. Oh, my.

Well, the book is Mars Rover Curiosity, an inside account from Curiosity's chief engineer, that being Rob Manning, co-written with William Simon. When will this actually be in people's hands? This one's not available until October, although you can pre-order it now. But there are two more coming out this summer pretty soon. Tell us about those. Well, the first one that's coming out is by Rod Pyle. It's called Curiosity, an inside look at the Mars rover mission and the people who made it happen. So this one's very focused on interviews with

personalities on the mission, both scientists and engineers. I haven't actually had a look at this one yet, but it sounds entertaining. The other one is by Mark Kaufman called Mars Up Close Inside the Curiosity Mission. This one's available in August. And it's a National Geographic publication. So like any good National Geographic publication, it is absolutely chock full of glorious, glossy photos. So definitely check that one out if the pictures are what you really want to look at. These other books aren't so much for the illustrations. And I figure as long as I'm mentioning books, I should mention that one of the scientists on the mission, Roger Wiens, who's the head of the ChemCam instrument, wrote a book that was published March 2013 on his perspective on the very tumultuous development of that instrument for

the mission. So that's also well worth checking out. Emily, I know of at least one more book about Curiosity that is still a little ways off. Tell us about that one. Right now, I am writing my own book about Curiosity, my very first book. It's going to be coming out sometime next year. And I'm really getting into the technical details about how this rover works, all the science is done on Mars, how its instruments function, what's up with the wheels anyway, and about the rather tumultuous development of this thing from its initial conception early around 2000 until it finally managed to land on Mars. Well, I'm going to put in my request to get you as a guest on this radio show that I do

now so that I beat the rush. Thanks, Emily. Thank you, Matt. She's the senior editor, our planetary evangelist at the Planetary Society, and a contributing editor to Sky and Telescope magazine. Up next, the boss, Bill Nye, the science guy, CEO of the Planetary Society. Hey, Bill, welcome back. Good topic today.

It just happens to be a follow-up to a commentary that you provided a few weeks ago. Coincidence? Perhaps. We're talking about the microwave radiation that was polarized, that was detected in Antarctica. And it turns out maybe it's not evidence of the Big Bang and consistent with Einstein's theories and all this stuff, that it's actually just an artifact of, what would you call it, intergalactic dust. Indeed. This has got to be disappointing to many people. It's the process of science, Matt.

These guys thought they had made a discovery, and maybe they have, but it was pointed out to them, to us, to the world, that there's another explanation that would yield the same results. And this is the way science goes. Since last February, for me, I've gotten involved a lot with the so-called, what I like to call the process of science. Science is a body of knowledge, to be sure, but it's a way of understanding nature. So these guys did their best to understand these signals that are hitting the Earth,

and they believed it was consistent with this old theory, but maybe it's consistent, but there's a different explanation, and that's science. That's to be celebrated. Exactly. Although I'm sure it's disappointing for those. And we're not done. It's disappointing so far. And I'm willing to bet that there will be some out there who will point to this and say, ah, see, scientists wrong again.

But the truth is it was other scientists who discovered this, and it's self-correcting. We love this. This is what we love about the process of science. And it also shows the importance of sharing information and having worldwide access to this sort of thing, and having a generation of people who are literate enough to evaluate the evidence going this way or that way. It's an extraordinary thing, and to me it's something to be celebrated, not berated. And I'm very glad that you decided to present this follow-up this week. Thanks, Bill. Oh, no, Matt. It is I who must thank you. When it comes to the galaxies, let's stay tuned. And change the universe. Indeed. He's Bill Nye, the CEO of the Planetary Society.

Let's look not too far out there, just 500 light-years, toward the first Earth-sized planet discovered in the habitable zone. 1,797 planets revolving around other stars. That's the count as I record this. There may very well be one or two more by the time my words make it to your ears. But of all those planets, the very first to be found in the Goldilocks habitable zone, that is also the size of our own world, went public just two months ago. The discovery of Kepler-186f is reason for celebration, not because its existence is a surprise, but because it will always be the first in its class. It took an enormous amount of work by a big team,

and it took an amazing space-based telescope that we've talked about many times on this program. The lead author of the paper in the journal Science was Elisa Quintana, a research scientist at the SETI Institute in Northern California. Elisa joined me via Skype a few days ago. Elisa, thanks so much for joining us on Planetary Radio, and somewhat belated congratulations on this discovery of Kepler-186f. Thank you, Matt. It was very exciting to see this.

I'm sorry I waited so long to give you a call so that we could hear about it, but at least some of the media interest has died down. I'm sure it was very busy there about two months ago in mid-April. Yes. In mid-April, we announced the system, and it did stir up quite a lot of interest. Pretty exciting. Very understandable interest. I mean, this is the first planet that is a really good parallel for Earth. Not everything is the same. It's not a twin. We'll talk about the differences between the stars, I hope. But

this planet is, how big is it? And how close to Earth's size do we know it to be? Okay, well, the planet, the radius is 1.1 times the radius of Earth, but it has an uncertainty of 10%. So within uncertainties of our measurements, it is consistent with the size of Earth. It is the first definitive planet that is consistent with the size of Earth in the habitable zone. As you know, Kepler, one of the primary goals of Kepler is to find an Earth-sized planet in the habitable zone of a sun-like star. So this is really a milestone for us. Mission's not over. We found a planet that's Earth-sized planet in the habitable zone of a Sun-like star. So this is really a milestone for us. Mission's not over. We found a planet that's Earth-like in the habitable zone around an M dwarf,

and we're still looking for more. Tell us more about this class of stars, these M dwarves, that happens to be of the type that Kepler-186f is revolving around. Sure. So M dwarves are smaller and cooler than the Sun. This Kepler-186 in particular is about half the size and half the mass of the Sun. And so since they're cooler, the habitable zone is located much closer in because it needs to find that warmth. It has to be able to maintain liquid water and not be too hot and not be too cold.

Planets that orbit close to the stars have shorter orbital periods, just Kepler's laws. So in a given amount of time, we get a lot more transits as compared to a planet in the Hubble zone of a star like our sun, which orbits every 365 days. This planet orbits every 130 days. And so having more transits allows us to find these planets more easily. Still teasing out the data that showed you that Kepler-186f was there. This wasn't easy, was it? It's not easy, definitely not.

The inner four planets orbit close to the star within 3 to 23 days. Those were found early on because they cause a significant deeper transit. Those were found early on because they cause a significant deeper transit. Because this is on a longer orbital period, it took us a lot longer to actually detect this planet. In order to confirm a planet, we like to see at least three crossings in front of the star, just to make sure it's not a fluke. At 130 days, it definitely takes a longer time to discover these. There's a really good graphic in a piece

that was sent out. It's actually part of an article that you wrote that was sent to SETI Institute members. It indicates pretty graphically how it is actually in some cases, I guess, easier to find a planet going around a smaller star like an M dwarf? That's the case, right? Yes. Kepler doesn't measure masses. It measures the size of planets. With a planet crossing in front of the star, it basically measures the ratio of the planet size to the star size. So if you have an Earth-sized planet around a smaller star,

that's a larger fraction of light is blocked as compared to an Earth-like planet crossing a larger G-type star. This means, since we measure the brightness, this means that we see a bigger dip, a bigger proportion of light is blocked out. Since these Earth-sized planets are so hard to find anyways, this really makes a difference. What else, if anything, do we know about 186F? I mean, can we tell even whether it is tidally locked to its star, or does it get to show every face of the planet to its star? Well, we know the inner four planets are tidally locked.

There are some models that can estimate how close a planet has to be, because basically it feels, it needs to feel the gravitational pull from the star. And that causes their rotational evolution to, as he said, get in a totally locked position where one side always faces the star. Kepler-186f is at a large enough distance, and it also orbits a brighter M dwarf. M dwarfs range in size from maybe a tenth of the size of the sun to half of the size of the sun. Kepler-186f is on the larger size for the class of M dwarf stars. This reason, and also because it orbits such a larger distances, we don't know if it's tidally locked. We don't know the age of the star, and that also makes a difference. The inner four planets only need maybe a few million years of time to become

tidally locked. We know the star is older than that. Kepler-186f would become tidally locked on the order of billions of years. And we just don't know how old the star is. So it could be, it could not be. These dwarf stars, they have quite a long life. That's right. So M dwarfs are interesting because they present a completely different set of challenges to habitability. As you said, there's the issue of tidal locking. That can definitely affect if a planet is habitable. One of the pros for planets around M-dorfs is that they are very long-lived. They lived for billions and billions of years, possibly even trillions of years.

So a planet that's in the habitable zone around M-dorf is going to stay in the habitable zone for a very long time. So that helps for habitability reasons. Elisa Quintana, lead author of the paper announcing discovery of the first Earth-sized exoplanet in the habitable zone. She'll tell us more in a minute. This is Planetary Radio. Hi, this is Casey Dreyer, Director of Advocacy at the Planetary Society. We're busy building something new, something unprecedented, a real grassroots constituency for space. We want to empower and engage the public like never before. If you're

interested, you can go to planetary.org slash SOS to learn how you can become a space advocate. That's planetary.org slash SOS. Save our science. Thank you. Your name carried to an asteroid. How cool is that? You, your family, your friends, your cat, we're inviting everyone to travel along on NASA's OSIRIS-REx mission to asteroid Bennu. All the details are at planetary.org slash B-e-n-n-u. You can submit your name and then print your beautiful certificate. That's planetary.org slash Bennu. Planetary Society members, your name is already on the list. The Planetary Society, we're your place in space.

Welcome back to Planetary Radio. I'm Matt Kaplan. My guest is SETI Institute research scientist Elisa Quintana. SETI, that's the Search for Extraterrestrial Intelligence, of course, but the Institute is also a pioneer in the search for the planets strewn throughout our galaxy that E.T. may call home. Or is that phone home? Elisa and her colleagues pulled Kepler-186f from the mountain of data gathered by the Kepler spacecraft, which has a new lease on life that will enable it to continue the search for exoplanets.

Elisa was telling us before the break about the type of star 186f and its companion planets circle. The lifespan of this relatively dim M or red dwarf should be many times the life of brighter stars like our own sun. There's at least a decent chance, since we don't know the age of this particular M dwarf, that conditions were pretty good for life long before they were good in this solar system on our planet. Being tidally locked doesn't necessarily preclude a planet from being habitable. There have been studies. There's another planet found by radial velocity. It's Gliese 581 d. It's about five Earth masses. It's not Earth-sized, but it is in the habitable zone. And there have been many

studies that have shown that it could maintain liquid water given a certain atmosphere. Even if Kepler-186 is tidally locked, there are ways around it. It depends on the type of atmosphere that it would have. And speaking of that atmosphere, do we know anything about, or even from models of other solar systems, of what this planet may be composed of and whether it even has an atmosphere? We don't know. As I mentioned, Kepler only measures a planet's size. It doesn't measure a planet's mass.

So we don't know the composition. What we do know is that planets that are about Earth's size have a high probability of being rocky or have a solid surface that can maintain an atmosphere like Earth does. The star is 500 light years away. It's too far to do any observing, even from our most powerful space telescopes, to get any information on that. This is a sort of a proof of concept that these planets do exist. We now know that Earth-sized planets exist around other stars in their habitable zones. NASA has two missions coming up. There's TESS, Transiting Exoplanet Survey Satellite, and the James Webb, which is a successor to Hubble. Those will be looking for planets like Kepler-186f, but that are closer to

us, you know, tens of light years away, and they will be able to probe their atmospheres and look for biomarkers. And this will happen in the next few decades, so that's really exciting. Yeah, we all have our fingers crossed for the James Webb Space Telescope, and we're going to have to talk to somebody about the TESS effort at some point as well. That has not come up on this show. You mentioned at the end of your article that you did for the SETI Institute that the Institute's Allen Telescope Array, the ATA, has been taking a look at these planets

that approach, or at least are somewhat Earth-like, and that Kepler-186f has been on that bill. No results, I take it. That's right. Since I mentioned the inner planets were discovered early on, SETI did include that in its target of small planets that they've been looking at. So they've really been observing it for years now. Even though this planet's too far away to detect biomarkers, having SETI observe it, that is probably the only way that we'll be able to determine if there is life on that planet. So we don't have any results yet.

Obviously, everyone would have heard by now if we did. But we're still looking, definitely. But 500 light years, that's a long ways for a radio signal to go, right? It doesn't rule out somebody transmitting from 186F. That's right. I forget the stats. Jill Tarter calculated it. But, yeah, they would need to have very, very powerful telescopes That's right. I forget the stats. Jill Tartar calculated it. But yeah, they would need to have

very, very powerful telescopes. All right. Well, we'll just hope for the same kinds of results closer in, as you were saying, from TESS and JWST, and more from Kepler, which it's thrilling to know that this mechanically troubled observer, this telescope in space, its life is not over yet. You guys must be excited that you're going to be able to continue to use it. Oh, definitely. The extended mission is now called K2. Kepler will be looking in the ecliptic. It's very exciting.

When the other reaction wheels failed on Kepler, all the news media was saying Kepler is dead, and it's far from dead. It's repurposed in a very exciting way. It's going to be looking at four different fields every year. That means many planets are going to be discovered. Lots of planets are on M dwarfs, assuming that they're abundant, which I believe they are, and a lot of more interesting astrophysics. The original Kepler stared at one specific field because we wanted to get statistics for these longer orbital periods. The way it's designed now has to look in the ecliptic,

for these longer orbital periods. The way it's designed now, it has to look in the ecliptic, and it looks at a field for 90 days. So it's going to be different. It's going to find different astrophysical phenomena, but it still is an exoplanet mission, and that's what's really exciting. My guess would be that every one of you Kepler scientists says a little thank you, at least in your own mind, to Bill Berucki every day that you get to do this

work. Oh, definitely, definitely. I actually came to NASA Ames in 1999 as a graduate student, and my proposal was to work with Bill Berucki on what was called the Vulcan Camera Project. So it was a CCD camera at Lick Observatory. So it's a ground-based photometry mission, and it was sort of a proof of concept for Kepler. So I've been working with him for years. I've seen what he's had to do to get the satellite up and going, and it's really nice to have all of these successful discoveries. He's still here working.

He's still very involved in all of the science. So, yes, we very much appreciate him and the work of Dave Koch. He was another person that helped develop this. Many, many people, of course. Elisa, I will wish you good hunting, and I'm sure that would come from everybody in the audience as well, and we look forward to many more discoveries like this

of Earth-like planets elsewhere in our galaxy. Yes, I should just mention that Kepler-186f was found with the first few years of Kepler data. We still, from the original mission of four years of data, we still haven't even searched through all of it. We have a whole other year of data, so who knows what we can find in that. So that's really exciting. And then, of course, K2.

K2 got approved. It's funded. It will be requesting information from the community to look for targets and expect to see a lot more exoplanets and small Earth-sized planets discovered in the next few years. Very exciting stuff. Thank you so much for joining us on Planetary Radio. Thank you. Dr. Elisa Quintana is a research scientist with the SETI Institute and the NASA Ames Research Center up there in Northern California, where, as you've heard, she works on the Kepler mission

and led this team that announced discovery of Kepler-186f, the first truly Earth-sized planet to be found in the habitable zone of another star. Many more in store, no doubt. And has been at the SETI Institute since 2006. Time to talk to another astronomer. That'll be Bruce Betts with a view of the night sky that anybody can see from standing down here on Earth as we pick up this week's edition of What's Up. Time for What's Up on Planetary Radio.

We are here with Dr. Bruce Betts. He is the Director of Science and Technology for the Planetary Society. And I congratulate you. Thank you very much. I assume for having the best sons in the world. Yes, that's exactly right. No, and I'm glad you said sons because daughters is the claim that I would make. Actually, not in the least.

It's something altogether different that I hope you will describe to the listeners. Okay, I'm guessing. Tell me if I'm right. It's a congratulations for the planetary study proposal getting selected by NASA to do a study on the life experiment. Is that correct? Bingo. Ah, yes. No, it's a good thing. So NASA selected our proposal

as one of 18 selected to do studies that are related to all sorts of topics related to the asteroid redirect mission. And ours is to study accommodation of our life biomodule living interplanetary flight experiment that's designed to carry little critters, microorganisms, to deep space, leave them there for a few years, bring them back, see how things fared. Last time we did that, we ended up back on Earth pretty quickly with the failed Phobos mission. We're looking into trying it again with this study. Though you did make it to up on the space shuttle, right? We did indeed. We had a successful flight of a subset of the microorganisms on the STS-134, the second-to-last space shuttle mission. I've got a blog that covers this. If you're interested in more detail, see planetary.org.

All right. The night sky. Night sky. Still got those lovely planets and some colorful stellar friends. If you look in the early evening, Jupiter getting lower and lower, so don't miss it. But it's over in the west shortly after sunset, looking super bright. And then rotate towards the south and you'll see reddish Mars and it is near bluish Spica, the star. And then further to your left, if you're facing south, you will find yellowish Saturn. And then if you keep going on a very approximate line, you will find the red star, reddish star, Antares. It's a colorful mishmash in the early evening and then in the pre-dawning, still catch Venus low in the east. And with Venus and Jupiter, their planet sails going soon, so don't miss them over the next few days and weeks.

All right, we move on to this week in space history. It was a sad week. In 1971, Soyuz 11, the entire crew died during re-entry. Yeah, very sad. And I am pleased that we will continue to mark that on this program. It should be marked. Yes, indeed. In a much more frivolous sense, we move on to random space fact.

Did you say dum-dum? I did. I said multiple random-dums. But this is not a dum-dum fact. Yeah, you didn't mean it. If you're hanging out, living on Mercury, as people don't do. mercury as people don't do so far as we know so far as we know people living on mercury would see one mercurian day every two mercurian years so it'd take two years two times around the sun for the sun to come back in the same place in the

sky where it last was. Weird. And you can therefore understand, I guess, why when I was a kid, astronomers thought there was no day at all, that it just was locked to the sun like the moon is to the earth. They did. And it is in a orbital resonance with the sun, but it is not in a one-to-one resonance with the synchronous locked rotation. So it's exotic and fun for those living there, I'm sure. On to the contest. All right, we asked you, what planet has the most moons over 1,000 kilometers in diameter,

and how many moons are there? How'd we do? Must be a lot of astronomical or solar system info sources out there that are in need of update, because we had a lot of people say that Jupiter and Saturn were tied or maybe it was just Jupiter. I believe that our winner, though, got it right, as do the majority of people. Our winner from St. Paul, Minnesota, Luca Roschino, who said Saturn is the winner with five, five moons of larger than 1,000 kilometers in diameter. Is he correct?

That is correct. Saturn has five. Jupiter, as well as Uranus, both have four. Easy to be confused because I always think of Jupiter as having the big moons, and it does. It's got the big four Gal-Land satellites. But then there's a huge drop-off in diameter before you get to the next biggest one. So Saturn winning and Jupiter and Uranus coming in a close second. Well, congratulations, Luca, you first-time winner. We are going to send Luca a copy of our friend, the meteorite man, Jeff Notkin's terrific little book, Meteorite Hunting, How to Find Treasure from Space. You can take it with you when you head to Antarctica or the desert or Mercury if you want to spend a long day up there looking for meteorites.

Yeah, you get a lot of hours of sunlight if you're on the day side. Lots of time for hunting. Yeah, all right. Take lots of water. On to our next trivia contest question. What are the montes or, named for on Mercury? What are all Montes and mountains named for on Mercury? Go to planetary.org slash radio contest.

You have until July 1. That would be Tuesday, July 1 at 8 a.m. Pacific time to get us the entry this time around. And if you get it right, and if you are chosen by Random.org, you will get version 2.1 of the Planetary Radio t-shirt, the one that includes Saturn, though not all those big moons. Maybe 2.2 or 3.0. Yeah, we're working on it. All right, everybody, go out there, look up at the night sky, and think about cobwebs. Thank you

and good night. You know, for years, I thought the cobwebs had nothing to do with spiders. They just formed spontaneously. Wait, they have something to do with spiders? He's Bruce Betts, the Director of Science and Technology for the Planetary Society, who joins us every week here for What's Up. Did the precursors of life on Earth include a fuel cell at the bottom of an ancient ocean? That's next week on Planetary Radio, which is produced by the Planetary Society in Pasadena, California,

and is made possible by the members of the Society who enjoy life to the fullest. Clear skies. Thank you.