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The Golden Age of Exoplanet Exploration (live public talk)

Hello and welcome to NASA’s Jet Propulsion Laboratory in Pasadena California for our monthly public lecture the von Karman series the title of our show this month the golden age of exoplanet exploration as we’ll discuss with our speakers later on there’s some room for debate whether that’s golden ages upon us right now or whether it’s still to come and don’t worry if you are scratching your head out there wondering just what the heck is an exoplanet we’ve got you covered we’ll hear from two speakers this evening followed by some discussion with them and then we’ll take your questions and if you’re watching our live webcast you can submit questions via the YouTube chat and we’ll take some of those later on and so to start us off our first speaker is a research scientist at the NASA exoplanet science Institute at Caltech where she searches for discovers and characterizes extrasolar planets she also keeps track of all the known exoplanets and their properties in nasa’s exoplanet archive please welcome dr.

Jesse Kristensen hi everybody I’m very excited to be here tonight to talk with you about the Golden Age of exoplanet exploration and not just because I believe it’s the Golden Age of exoplanet exploration for everybody but that it really is genuinely for me personally let me tell you a story fifteen years ago when I was a fresh-faced young grad student looking for a research project exoplanets had just started to capture the public imagination and I thought now there’s an exciting idea I could hunt for planets so I set out on a quest I would find an exoplanet the first two years of my thesis I did a survey from the South Pole in Antarctica no exoplanets the second two years of my thesis I did a survey from the countryside in New South Wales Australia no exoplanets I got a thesis but no exoplanets I moved to the US and did a research position at Harvard University I spent two years using the nasa EPOXI mission to look for exoplanets no exoplanets so at this point I had looked at literally hundreds of thousands of stars looking for exoplanets and I was starting to feel a little discouraged but then I got the email that would change my life which was an invitation to join NASA’s spectacularly successful and sadly very recently departed Kepler mission now with Kepler I was lucky enough to find thousands of exoplanets so for me the quest was finally realized and it truly is the golden age of exoplanet exploration because those thousands of exoplanets have turned out to be so much more incredibly diverse and interesting than we even could have imagined so let’s go on that journey okay so let’s start a step back for a second what is an exoplanet okay this is a graphic of our solar system not to scale we have one star in our solar system the Sun our Sun is a star we have eight planets boo hiss Shh I know I know tomorrow night Mike Brown is talking all about why he killed a Pluto down at Caltech so go see that talk okay we have eight planets we also have dwarf planets which is this new bucket that Pluto and his friends all fell into place Edna Makemake Eris and Sarah’s they’re all dwarf planets we also have minor planets which is basically everything in the solar system that’s bigger than a grain of dust that we’ve managed to catalog and we have found over 700,000 of those the solar system is a dusty place but what our exoplanets exoplanets are planets around other stars for thousands of years people had thought about the idea of exoplanets our Sun is a star our sky is full of stars do those stars have planets around them too so over 2,000 years ago the Greek philosophers were talking about this they were theorizing whether earth was singular or plural were there other Earth’s out there and they were talking about it in a very hypothetical sense kind of the way we think about multiverses today like a really cool thought experiment but like no chance of ever really testing it but they thought it was fun to talk about they did the Greek philosopher thing of just sitting around and chatting do you think that there’s one earth or multiple earths so a few thousand years go by and we come up to the Renaissance the Renaissance was a good time to be a scientist was a bad time to be a scientist who said this there are countless sons and countless Earth’s all rotating around to their sons in exactly the same way as the seven planets of our solar system this was before Neptune and then Pluto and they’re not Pluto again so they were seven so this was Jay Don Oh Bruno who was an Italian mathematician who was burned at the stake for saying this amongst other things he said a lot of very silly things about the church at the time when you shouldn’t have said silly things about the church but this is one of the things he said that got him in hot water that there were planets going around other stars so one of the reasons I particularly want to bring up Bruno is he really articulated for the first time that we know of why we haven’t found them yet we’ve been imagining them for thousands of years why haven’t we found them yet because stars are really big and really bright and planets are really small and really dark it’s incredibly hard to solve that problem so let’s go forward another 400 years or so and we get to 1950 52 – a man called Otto Struve and he comes up with an idea of how we might do this how we might detect these exit weapons so in 1952 we already knew about binary stars so two stars going around each other orbiting each other and they can all be very close to each other binary stars can orbit each other in just a few hours or a few days if you look at the stars in the sky you can see them doing this they move towards you and move away they move toward you they move away as they’re dancing around each other we knew that already and Otto said what if we take one of those stars out and put a planet there instead it would have to be a really big planet and we’d have to be very close to the star orbiting the star in only a few days but maybe if the planet was big enough and close enough we’d be able to see the motion of That star what he was proposing is the radial velocity method this is one of the ways we used to detect planets so here’s this star in the middle of this exoplanet system and here is I’m still just getting used to this here is the planet going around so the star moves towards us at the moment and then wait a little bit and the Stars moving away from us again we can see this in the light curve of the star that the Stars moving towards us in away from us the thing is everybody at the time I can only imagine was like Auto that’s crazy I assume his friends called him Auto the reason that’s crazy is because until that point we only had one planetary system which was our solar system and I showed it to you we have rocky planets small rocky planets close to the Sun and big gas giants and ice giants further out that’s what our solar system looks like so all our theories about how planet systems form and evolve and migrate we’re geared towards reproducing our solar system if your simulation created a giant planet like Jupiter and then moved it right next to the Sun well you’d be like okay I’ve got a I’ve got something wrong I’ve got to go back to my calculation to try again so this idea that he had that we could detect these planets the idea that these planets would exist was very crazy an alien let’s fast forward 40 more years 1995 the first exoplanet was finally found after thousands of years of wondering whether there were planets around other stars the first planet orbiting a star like our Sun was found and it was found using the radial velocity method which is an amazing thing so for 40 years this paper had like seven citations now it’s had 700 because everyone’s like oh he was right that’s cool the other method I want to talk about because it’s important for the rest of our talks is the transit method this is another way we use to define to find planets and it’s the most successful one we’ve used so far so the transit method relies on the fact that if your planet system is lined up just right then the planet will go in front of the star that you’re observing now we can’t resolve this with our eyes we can’t see your planet going in front of a star but if we’re just measuring the brightness of That star over and over and over again occasionally when the planet comes in front there’ll be a dip the star will look like it gets dimmer just for a little little while and then it’ll get bright again and then sometime later it’ll get dimmer again so if you were an alien civilization looking at our Sun and you were lined up just the right way every 365 days you would see a little dip and that would be Earth going in front of the Sun so this is the transit method so what we do is monitor the brightness of tens or hundreds of thousands of stars which is what I did during my thesis and look for these dips and with this transit method we’ve managed to find thousands of planets and they were nothing like we expected so as I said we were expecting to find our solar system that’s all we knew and we went out there and we found anything but so what did we find the first kind of new interesting we found thing we found because it was the easiest thing to find with these hot Jupiters we call them hot Jupiters because they’re jupiter-sized planets that are thousands of degrees and we have no imagination so they’re called hot Jupiters and the first one we found was called 51 peg so what I’m going to show tonight are a series of the exoplanet exploration officers travel Bureau posters and I believe there are a bunch of these available for people to take tonight so this is also an advertisement for the excellent excellent graphic artists we have here at JPL so this was the first planet that was discovered the reason there are several other planets on this posters there’s some debate over which planet was found first and by whom and when it was confirmed always the way everyone’s racing but here’s our first exoplanet and it was a hot Jupiter and so we found many more of these now and as I said they completely trashed our previous theories of how planets formed now we have to somehow form a giant planet probably far away from the star although there’s a few theories that they might form right next to the star then we have to migrate it all the way in but not all the way into the star has to stop a few days away from the star and sit there for a while and there’s all these interesting properties of these planets my favorite hd1 8 973 3 B is a is a really well study it’s a really real really well study planet we’ve been able to measure the composition of its atmosphere and Carl will talk a little bit about how we do this we’ve been able to measure the wind speed in the atmosphere and we’ve been able to measure the temperature of the atmosphere so for this planet HD one eight nine seven three three B when I say it’s hot it is so hot it is raining liquid glass sideways in the atmosphere of this planet so yes we’re we’re waiting for spring to come back to LA there they’re already deep in summer all right we didn’t just find big hot planets we found small hot planets as well this new class of planets that we call larval worlds these are planets which are rock little rocks but they’re so close to their star again like these hot Jupiters that there are thousands of degrees so they’re so hot that their surface is a molten lava world’s the first one we found was kepler-10c and now I want to say it was B I want to say C kepler-10c and which was the first sighs planet we found so this one 55 Cancri E is actually twice the size of Earth which leads me to my second big class of interesting planets that we found which is super Earths because we want to get funding so we call them super whatsit super earth so here I’m going to show all the planets in our solar system to scale so we’ve got Jupiter Saturn Uranus Neptune then we have the inner planets Venus Mars Mercury okay so you can see already there’s an interesting structure just in our solar system we have these four small planets and we have a big jump to the ice giants and then we have another big jump to the gas giants this is where 55 Cancri EU eyes it’s two times the size of the earth and actually when we look with the Kepler telescope these super Earths or sub Neptune’s depending on who you’re trying to get funding from are the most common kind of planet we found they seem to be everywhere and that’s a mystery because in our solar system we have eight planets we have nothing in the size range but these seem to be the most common planets out there now the reason it’s a fun mystery for the rest of us is what are they made of are they rocks that got big are they ice giants that got small are they something we don’t have in our solar system like Waterworld some of them seem to have the density of the same density as water is it just a big glob of water really hot water so it’s a mystery and it’s really exciting because we love mysteries so we have this whole new class of planets we found called super Earths okay so we haven’t just found diverse kinds of planets we’ve also found them in very diverse situations so I stressed at the start that our solar system has one star now who here has seen the original Star Wars yeah yeah it seems like that kind of crowd so in in in a new hope you have Luke standing on the surface of Tatooine watching the Sun set how many stars are there two so George Lucas had this vision like 40 years ago that there could be planets around binary stars this was before we even knew there were planets and we found it we found Tatooine we call it kepler 16b but it’s a planet that orbits two stars and actually if you do the correction if you do the color correction right they’re the same color is the two stars in George Lucas’s imagining of this the sizes aren’t quite right relative to each other but the colors are right so then he did really well and so far we found really a dozen of these circumbinary planets which is really interesting because half the stars we see in the sky are binary systems so knowing that they can have planets around them that you can have stable planetary orbits around binary systems really opens up the possibilities of where we might be finding these planets so that was really exciting another thing we found that’s really different from our solar system is really crowded planetary systems so in our solar system mercury is the closest planet to our Sun it has a period or a year of 88 days it takes 88 days for Makery to go all the way around and come back this what I’m about to show you is a system called k2 138 which was found by citizen scientists in a project that I helped to start it has six planets that all have periods of 42 days or shorter so mercury is out here 88 there are six planets halfway between that distance and that star that’s really incredible ecosystem is stable is really fascinating all the planets are in resonance with each other alright the five inter planets are all in resonance with each other so that means that their periods are related to each other by multiple integers so for every three times the inner planet goes around to the next planet goes around twice for every three times that planet goes around to the next planet goes around twice and so on 3 2 2 3 2 2 3 2 2 all the way out through that system what that means is the system is musical because because resonances are musical intervals so let’s listen to what the system sounds like so every time one of the planets transits it makes a bawling sound and the bong is related to the period the high-pitched one is the fastest-moving planet and the low-pitched one is the slowest moving planet the reason it sounds good is the three to two ratio is the perfect fifth interval which if you if you’re into musical theory is a very standard tonic chord in the western music theory so this is just your moment of sin in the middle of my talk it just relax and listen to the music and think about the fact that these planets these planets are actually all only in less than 13 days the sixth planet is way out there at 42 days this is five planets in periods 13 days and shorter so I want to acknowledge that this animation was made by Matt Russo of system sounds he has made a bunch of a very awesome sonification of other exoplanet systems and solar system objects as well so go to system sounds and check that out okay so some of the planets in the k2 138 system are starting to get exciting for another reason not just because they’re in compact systems and not just because there isn’t it but because they’re small one of our goals is to find planets like the earth so what do I mean by planets like the earth we have to be careful here there’s lots of different ways a planet could be like the earth one is the size so we think planets the size of Earth are probably rocky if they were made of gas there was not enough matter that’s not a mass to keep them as a ball so they probably need to be made of rock we need them to be the right temperature for liquid water and we could have a whole nother talk about what we mean by habitability and where life to be but the only place we know where life is is earth and all life on earth needs liquid water so we make that a criteria the temperature needs to be right for liquid water on the surface the other third criteria is that it’s orbiting a star like the Sun and I’ll explain a little bit more about why that’s important in a minute but we have found another very interesting compact system of these small planets called Trappist one hopefully you’ve heard of Travis one it’s one of our incredibly exciting rich planetary systems that we’ve found it has three planets that are the right size and the right temperature so that’s really exciting it’s also was discovered in part by the spectacular NASA telescope Spitzer and k2 k2 was a successor to the Kepler mission so we’re particularly proud of it but this is starting to get towards the thing we’re really asking about the whole purpose of the NASA Kepler mission was to measure how common are planets like the earth the right size the right temperature around the right kind of star and what we found is we think we had to make some guesses but we think that these planets are incredibly common so how many of we found look I lost my thing there we go okay so we have found seven seven planets to the right size and the right temperature so they are Proxima Centauri B so hopefully you’ve heard of Proxima Centauri it’s the closest star to our solar system so there’s a our closest star system has three stars in it Alpha Centauri a Alpha Centauri B and Proxima Centauri and we found a rocky planet of the right temperature around Proxima Centauri that’s really exciting that’s that’s you know light-years away that’s milliseconds or is but it’s very small here are the three Trappist planets that I just talked about trapars two one eat wrappers on F and strapless one G or rocky at the right temperature and then there are three more planets that we found with radial velocity GJ 667cc or transit Kappa for four to be and kepler 186f which are also in the size range in temperature range the problem with all of these planets is the kind of star that they orbit so remember I said they need to orbit stars like the Sun all seven of these planets orbit are much smaller much cooler kind of star called an M dwarf so our Sun is just a boring middle-aged yellow G star this is how astronomers classify stars with letters so these are all M stars so that most of the stars in the galaxies are actually M stars 75% of the stars are M stars or M dwarfs or red dwarfs there’s another thing you might have heard them called the problem with M dwarfs is that relative to the Sun they put out much more of their energy in UV radiation so UV radiation is the thing that here on earth will give you sunburn or feel really unlucky cancer and that’s because the high energy high high frequency radiation mutates your DNA and in fact cleanrooms around the world use UV light to sterilize things to make sure there’s no life so we found all these rocky planets at the right temperature but we don’t know they could all be completely sterilized by the radiation from their M stars so how many planets have we found that are truly like the earth that are the right size at the right temperature around stars like the Sun none yeah ah but as I said it’s not because we don’t think they’re common if we make some extrapolations from the Kepler data we think that they’re actually quite common and there could be tens or hundreds of millions of these in the galaxy the problem is they’re still too small and too far away from their star and the stars that they orbit are too far away so we’re kind of stuck at this point again at this precipice where our imaginations have gotten ahead of ourselves we can’t we don’t have the technology to realize our dreams and find these things that we’re thinking about like the same situations the Greeks are in 2,000 years ago they had dreams but they didn’t know how to do it but what we want to do is take these realizations these these illustrations these artists concepts and turn them into real observations of real planets but this time we have a plan so this is our NASA exoplanet mission roadmap or our exoplanet missions swoop as we call it we’re about here so we had to say goodbye to the Kepler mission recently the test mission which I didn’t get a chance to talk about but is our new planet finder we launched last year already finding planets very exciting the James Webb telescope is just around the corner and then we have more technology in the future that we’re building towards now and I’m going to let my colleague Kyle tell you about how we’re going to turn our dreams into reality how we’re gonna go from imagination to real observations so thank you very much thanks Jesse SETI stuff well now that you’ve heard a bit about the kinds of exoplanets that scientists are discovering out there our next speaker as Jesse mentioned will shed some light on what it takes to actually find and study them and coming up right after that my colleague philia will show you a fun tool that we’ve developed for imagining what it might actually look like if you could stand on the surfaces of some of these planets but up first our next speaker is the chief scientist in nasa’s exoplanet exploration program office here at JPL he acts as a principal adviser to nasa leadership in the development and operation of exoplanet space missions like some of these he has extensive experience in studies of exoplanet formation and concepts for missions that could directly image some exoplanets so please welcome dr.

Karl staple felt hey good evening everyone it’s really great to be here because I have been in this audience so many times it’s my first time up on the stage as part of the presentation so I’ve been at JPL for quite a few years now but I started out as a grad student down at Cal Tech with a summer job here in 1985 and that was a time when we did not have exoplanets I didn’t have the opportunity like Jesse to not find planets in my thesis because nobody was finding them we weren’t even looking really but what we did have happening at that stage of astronomy is we had found the first evidence for clouds of dust and gas orbiting young stars these orbit like in a flat pancake like shape and theory had told us for a long time that these would be the likely environments where a planetary system could form so we were starting to see that maybe if the formation of them the conditions were widespread for that planets would be widespread too so I kind of had a feeling that there was going to be some real mileage in this field coming up in the future so fast forward from that grad student now I’ve got a chance to really direct what NASA is doing along with my colleagues in the exoplanet program office and that’s really exciting so Jesse’s told you about how we’ve counted up large numbers of planets we’ve been able to measure their sizes with missions like the Kepler telescope so the thing that we want to be able to do next is go to understanding what these planets are made of how similar are they to the earth in their conditions and in terms of their temperatures and their composition so I’m here to tell you about what our plans are for being able to do that and in particular for small planets like the size of the earth the hot Jupiters have been very easy to find they’re fascinating but even more fascinating is to know how common are planets like the earth out there so we’re headed towards that goal so I’m going to show you a few graphs that tell you how astronomers expect to be able to recognize an earth-like planet when they see it or at least start debating seriously if it’s earth-like so let’s start here out here with this graph so I’m showing you here on the horizontal Direction a color of light here is a blue light that you can see when you’re can I here’s a red light and if you go past where your eye can see your wavelengths we call near-infrared the brightness here and the blue curve this is brighter higher up in the graph fainter going across this shows you the spectrum of light that is reflected off of the earth so all the colors broken down into a brightness number for every wavelength of light and what’s important about this graph is that you can see number one in the blue the earth is brighter in the red it’s fainter that makes you have a blue planet all right then in addition we can see that there’s this big dip in the signal over here where water vapor produces an absorption and we’ve got that same thing here and here from water vapor but most telltale of all of the earth is this presence of molecular oxygen in our atmosphere produced by life which sustains all the animals and so this is something that we would really like to be able to see in an exoplanet now compare this to Mars Mars has very little light in the blue it has a lot more light in the red that’s a red planet and so going across here you notice no oxygen signature no dip in Mars at the same wavelength of light and there really are two neat strong water features from Mars either there is a little bit of a feature here which when I go to the next slide you’ll see actually is carbon dioxide because and this is the atmosphere of Venus shown in comparison to the earth and all of these strong dips in the spectrum of Venus are due to carbon dioxide in its atmosphere there’s a little bit of that for Mars carbon dioxide you know here and here and there is a lot for Venus so again no oxygen and Venus and very little water so now astronomers have been imaginative they’ve made computer models of theoretically possible planets that would be rocky like the earth that would have different atmospheres and so the orange curve here is showing a planet that has say no water vapor at all but has really huge amounts of oxygen maybe ten times the oxygen that we have in our own solar system and this is an example of dozens of possible scenarios that have been exploring computers so we have a understanding of planetary atmospheres predictions about the possible diversity that would be out there so what we really want to go is find and measure the spectra of lots of small planets see what the diversity of them is and see how many match the spectrum of our own earth so let me talk to you about how we do that now the most normal thing you would do is you would just want to be able to look at the light that reflects off a planet that’s what we do with the moon at night we see the sun’s light reflecting off of it the way we see Mars and Jupiter and all the great pictures is from the light of the Sun reflected off of it so we’d like to do that with exoplanets too but the problem is that glare from the star the star is so close together to the exoplanet when you look out at a distance of you know many light-years it’s very hard to separate the light of the exoplanet from the light of the star so right now we have zero exoplanets that we’ve been able to measure in the reflected light that you use your own eyes to see planets in the night sky here so we actually though have been able to develop a technique that can still get you a spectrum in a totally unexpected way and I want to talk to you about that here so this is an example of things that are lit from the front and the sunlight is reflecting off like a planet so here’s a cloud here’s me at the launch of tests this is Saturn’s moon Titan and this is Venus as seen from a spacecraft now what if you give up on trying to separate the light of the star from the light of the planet if you are willing to combine them together you can actually still see a signal from the planet itself so in that case what we’re doing is we’re using the silver lining of the planet to probe its atmosphere so here’s a cloud silver lining here’s me in the studio back on Wednesday when you light me up from behind you can see maybe I’ve got gray hair you can see that I believe got some blood flow in my ears but then this is the picture of of Titan taken by the Cassini mission JPL’s Cassini mission at the particular time when the Sun was directly behind Titan and you can see the same Silver Lining effect here that the light of the Sun is passing through the upper atmosphere here so even if the Sun is still in the same picture as it is here back in 2004 when Venus was crossing the face of the Sun there’s this little thin film on this side which is light that’s transmitted through the miss fear of Venus so for the time being we’re not separating the light of the planet from the star in in in most cases we have only a couple dozen planets we’ve been able to get a spectrum this way out of the thousands that Kepler has been able to find so far but we can use this technique to go and find the spectra of planets around stars Hubble has been able to do this in some limited way for hot Jupiters it’s been able to see that yes they have water vapor in their atmospheres but the big coming activity in these backlit planets is the James Webb telescope it’s supposed to launch now in 2021 so right now James Webb is famous for being late and for costing more than expected but in like three years it’s going to be famous for a lot of important discoveries and in the early universe seeing the first galaxies and it’s going to be famous for what it does in exoplanets too because it’s going to be much larger mirror than Hubble almost a factor of three larger mirror and it’s gonna work in the infrared which is really good for studying the atmospheres of planets and so here it is after it’s deployed out in orbit it’s got these 18 segments on the mirror here a sunshade to keep the whole telescope cold it’s operating in the infrared almost exclusively and so James Webb is going to be able to do this kind of result in backlit planets so here’s the Trappist system Jessie mentioned to you with that fierce little red dwarf star with all the ultraviolet light and the three planets here in the middle are the ones that have the right conditions apparently for having liquid water on their surface so the people who are going to use JWST the James Webb Space Telescope have simulated what they believe they’ll be able to achieve on this planet which is planet b c d e f Trappist 1f and so this is a signal that they expect to be able to get where the differences between the planet when it’s crossed in the star when it’s crossing in front of them on the planet crosses in front of the star you take a spectrum when the star is there by itself you take a spectrum you make the difference between those two so you have a condition where it’s the star plus the backlit planet signal and the star by itself take the difference and you can then get this spectrum the vertical axis here is parts per million so this is how much the light is going to change because of that planet passing in front and these are water vapor features so we think that there will be dozens of planets like the ones Kepler found that have sizes like twice in three times the earth that will get spectra from with JWST we also think there will be a few around the size of the earth like Trappist here that we should be able to characterize so but I want to get back to that first problem how are you gonna be able to see the planet the normal way lit from the front reflecting the light of its star well it’s been reckoned that it’s similar to the problem of seeing a firefly you know next to a searchlight when you’re all the way across the country on the East Coast from here okay so the brightness difference is very challenging and the tiny separation between the two is very challenging think about also like you’re driving on a road at night and you’re trying to make sure you can see the road and the car is coming at you with with headlights and there’s billions of headlights in your rear-view mirror that that’s the kind of you’re trying to look out the window at the same time and you’ve got all this light shining in you from the cars behind you it’s just very very difficult to be able to do that but that’s our job and the NASA exoplanet program is to develop the technology that will make this brightness difference problem go away to get the glare of the star under control to see those faint planets so now I’m going to show you another graph this is a showing two different directions up on this direction is the brightness difference so up here are the few planets have been able to image today using telescopes like Gemini in Hawaii and in South America and there’s a roughly a dozen or so of these and these are about 10,000 times fainter than their star and you can see they’re out at this separation of about one arc seconds so that’s easy that’s only one tenth of the way to the East Coast to be able to see those planets so but the we’ve got to go from a factor of sort of ten thousand to a million where these are down to where the earth where it would be as if you were seen from 30 light-years away this so you can see Venus is closer and brighter than the earth Jupiter is further out because it’s such a large planet it reflects a lot of light and so it’s brighter and that’s down here at one billion-to-one contrast and the earth is down here at 10 billion to 1 contrast so you may be surprised to learn that we have about two minutes walk from here a vacuum chamber testing facility where we have a coronagraph instrument which blocks the light of the star to let you see something faint next to it and we have already achieved 1 billion to 1 contrast that a few beam with separation from the star it’s in the lab it works we’ve been developing an instrument concept based on it and so we think we have done all gone a lot of the way toward demonstrating that we can do this kind of measurement we just want to get it out of the lab and onto a space mission and that next space mission for that is called w first so this is a telescope that was recommended by the 2010 to Cadle survey of astrophysics its primary goal is a really wide angle camera view of the sky for dark energy extra galactic science and also for counting planets by the micro lensing technique I won’t go into that but you could ask me after the talk but W first has a second instrument in addition to its wide field camera it has a coronagraph like the one in our test bed facility so we’re gonna get a first chance to go and see planets around other stars that have been found by the radial velocity wobble technique that Jesse spoke of so that’s the first step W first will get us to a Jupiter around another star factor of a billion to one they won’t get us to ten billion to one which is an earth-like planet so just as W first was recommended in 2010 we have in 2020 another time on the National Academy of Sciences is going to recommend what should NASA do as this next large telescope project there are a lot of ideas some of them are not exoplanets they all have strong merit but there are two ideas that our exoplanet focused the NASA’s invested in the developing the concept I just want to tell you about them briefly now one of them is called hey BECs it stands for the habitable exoplanet Observatory so it’s a telescope about 60 percent larger than Hubble with one of us coronagraph instruments put inside tuned up to go to ten billion to one using the lessons from the W first coronagraph and then it also has a separate formation flying star shade spacecraft which provides an alternate way of blocking out the of the star and seeing the planet the star shade is particularly useful for letting a smaller sized telescope look closer in than it otherwise would be able to do so hey BECs is something that would probably able to see hundreds of planets of different types and planets that are like the Earth’s size in the habitable zone probably about ten is our current estimate those estimates all rely on what Kepler told us about the frequency of planets and so this is one of the two ideas the next one is called leVoir so Louvois R stands for large ultraviolet optical infrared telescope and so this is much bigger than Havoc’s this is a telescope now that is about a factor of let’s say this is this is also three times bigger than Hubble for the eight meter version I’m showing you here there’s also a 15 meter version and so this is a telescope that because of its larger size and would have a better ability to look in close to other stars this would be able to get 30 or so earth-like planets we believe for a rocky planets in a habitable zone for the small version that you’re seeing here and a larger version not shown you’ll be able to get about 60 of them so like JWST it has a segmented mirror that would have to unfold on orbit it has a very large sunshade to keep the temperature of the telescope regulated so these this is a mission concept it’s not approved it’s an as a suggestion for what we could do as the next major goal so what will our de kado Survey coming up decide they’re just starting to meet now we think we are close to being ready to build these kind of instruments these kind of missions but it’s up to our peers in the community to trade off this possibility versus other things that might be done and say whether we get the signal for go in 2022 so let me try to say where we’re gonna end up with this Galileo with his first telescope was able to look at Jupiter and see the moons of Jupiter he took what was a point of light in the star and showed that it was a system and at that time he could only hand draw what he was seeing so that’s what you have here on the left from night tonight the moons moved around so it with modern ground-based telescopes we’ve been able to see one really fantastic system with four planets that actually over the past you know ten years or so have been shown to orbit around this is a time-lapse photo by Jason Wang at Caltech and if we’re successful both in our technical work and in convincing the community this is what we hope to be able to do around 2035 with a loofah or a head next mission see our solar system the analog of it around many many other stars and tell us if planets were the properties like the earth are really common or very unusual and so another point when I conclude on is that once we find out that there is a planet at the right distance from its Sun to be the right temperature and it has the composition of the Earth’s atmosphere that’s going to captivate people if you’re ever going to go and try to have interstellar travel you’ve got to know what the destination is first you have to get the map for the travelers well this is the kind of way we could get started on this in the next decade having these missions that can find where are the nearest earth-like planets so with that I’ll turn it back over to Preston so we will not be turning it over to Preston hello my name is Talia Rivera and I work for NASA exoplanet exploration program I do communications and one of the things that was mentioned earlier was the exoplanet travel Bureau so Jessie in her talk earlier showed you the posters that we have created to visualize some of these exoplanets but what I will be showing you is where they live and also a an immersive 360 VR experience that you can all enjoy at home so let’s explore the galaxy so you guys will be able to find full resolution files of the exoplanet travel Bureau posters available at exoplanets nasa.gov but you will also be able to explore these surfaces of four different exoplanets that we’ve actually discovered so this planet right here is called 55 Cancri E it is one of the lava worlds that Jesse mentioned earlier so let’s explore the surface so these 360 VR experiences work on your desktop a tablet or your mobile device so you can use them as a 360 experience on a desktop or tablet but if you have a Google cardboard or a similar device you can get it on your phone split it into a stereoscopic view pop it into your device and view it in the or mode so some really interesting features here on this planet that we’ve highlighted with these text hotspots are the star so if you click that text hotspot it actually gives you some more information about what you’re looking at so here it gives information about this star which appears to be really close it is not a fountain of lava but it is the star in this system so this star is 65 times closer to this planet then our Sun is to earth which is why it looks so big and one of my favorite features when I was working on developing this product is right here what appears sparkles in the sky the these are actually sparkly clouds of silicate in this planet as Jessie mentioned earlier is so hot that silicate would evaporate and create clouds so if you click on that it tells you a little bit more and these clouds would reflect reflect the surface of the lava so they would look sparkly so again you guys can find the VR and all of the travel posters available for download and used at home you do not have to download any apps to use the VR it runs directly from our website and that is all available at exoplanets nasa.gov thank you all right Thank You Philly and if my my speakers will join us so over here and we’ll get started soon with the discussion part of our show tonight be sure though to check out the exoplanet travel Bureau online Philly I don’t think it was mentioned she’s actually instrumental in making those visualizations and so she’s really talented and I think it really does a nice job of demonstrating how there are careers for all kinds of folks at NASA working as part of the space Crypt program whether you’re a scientist an engineer or a communicator and all kinds of other things so I think it’s a great way to highlight that so let’s move on to the discussion part of our show with Jessie and Carl hey guys but thank you so I wanted to start by asking you a question I told you I was going to ask which was about the names we wanted to talk about the names of the planets and why they’re so funky yes so I want to apologize on behalf of my entire profession the names of garbage they’re almost always either named after the star if the star already had a name and the star names usually start out as garbage they’re almost all numbered so HD one eight nine seven three three was Henry Draper’s 189733 star that he put in his catalog so then we add a little B to the end to say that’s the first planet we found or little C is the second planet or little D is the third planet so you end up with these big names if the star didn’t already have a name then it’s named after the mission that found it so Kepler 442 B for instance was a 440 second planetary system found by Kepler That star didn’t already have a name that was in common use we do give some of them names sometimes where there’s occasionally there will be there will be in a kind of an exciting name right and they’re like a marathon or so I you had this name EXO world’s competition a few years ago where they there were like 50 planets that they had a basically a vote where you could vote for very cool names so some some of them do have I a you names the professionals never use them there will be a second round of I you naming coming up I believe this year so stay tuned to websites you might be able to submit your own suggestions so are the title of our show the Golden Age of exoplanet exploration I wanted to ask you for your take on that is this the golden age now and I think you mentioned that you sort of had it had that opinion is it with us now or is it still in the future I’m going to be evasive and give two answers I think of counting planets it really is the golden age finding so many and their sizes and you haven’t even heard the half of it because the test mission that launched last April is going to be expected to find another 10,000 or so planets above the 4,000 we have now and the European Space Agency has a mission called Gaia which uses another wobble technique to measure the stars and we’re expecting tens of thousands of planets to be found through that again indirectly so counting it’s the golden age in terms of characterizing and measuring their properties I think that age is still to come well then so let’s talk about that how far can we get down this path of studying exoplanets and finding them and studying them with telescopes alone I mean is there a limit to how much we can learn about exoplanets without actually going to one well we can look at our own solar system for the answers to that there’s a lot of planets that we haven’t gone and landed on yet we can learn a lot by looking at them remotely but we always get more answers when we go there and land a robot or a person on the surface and they can actually bring stuff back or take instruments to actually measure so we can get very exciting and very interesting ways there but there’s so much more we can get if we get there one of the jobs of our office is to plan the future of exoplanet exploration at least the options that can be presented to the community to evaluate and so of course we’ve thought about what might happen after a have X or a leVoir if they might get suggested so keep in mind all those future missions would only be able to show you a point of light and measure its spectrum they wouldn’t show you the geography or the cloud patterns on those planets but you can think about what a mission would be like that could do that so right now we’ve only planned to make our missions good enough to separate the planet from its star well it turns out that the Earth’s size is about 120 thousandth of the separation between the Earth and the Sun so if we just scale up leVoir by a factor of 20,000 then we’ll be in a position to start seeing features on the surface of that planet now that’s actually too big of a telescope to make all in one piece but there are techniques in astronomy to combine the light of two separated telescopes so these would be separated by quite a while so take 8 meters for Lu 4r x 20,000 so you need things that are separated by a hundred thousand meters or so to be able to do this more than that 160,000 but you can think about being able to make a mission like that physically possible so then what happens whether it’s soon or much farther down the road though what happens when you find something that might be an earth-like planet what will that do to the search and the study of exoplanets right well before 1995 there was actually a hundred and fifty years of claimed exoplanet detection that were then retracted and then claimed exoplanet detections that were then retracted when you’re trying to make these really difficult measurements right at the edge of your ability to do it you’re going to get it wrong a few times so the very first time we think we found a black planet it might not stick we’re gonna have to go and look at it with bigger telescopes different instruments and then we’ll see but everybody on earth will throw every telescope at it essentially as soon as we find one we’re just going to concentrate every single photon given well for the imaging method that we’re really focusing on you have to do a series of checks you have to make sure that something that’s really faint next to your star actually belongs to that star that it’s not in the background so we have to do a check and wait to see if that planet candidate moves with a star then if you see that it has that the right spectrum to be the earth we have to ask well is there life on there or not clever chemical modelers have figured out a way to have oxygen in the atmosphere of a planet without life a completely abiotic oxygen atmosphere so we have some tests that are being flown up now about how you might be able to tell that kind of oxygen atmosphere from a life-bearing oxygen atmosphere so I think there will be a lot of discussion and debate and just as Jessie says maybe some retractions but I’ll just spur you know further progress towards a really solid result ok then and then on that thread thinking about looking for earth-like planets and considering life do you guys have a belief personal or professional about the likelihood of that there is life beyond Earth well it’s hard to imagine that that if the planets are as numerous as Kepler is telling us and the conditions that the universe is made of the same substance as we have here on earth the conditions seem to be possible for life in many settings but whether that actually progresses the star is quiet enough long-lived enough whether it progresses to multicellular life and then intelligent life is something that’s still a totally open question and we have room for speculation as you see in the movies and on TV yeah so on earth basically as soon as Earth was able to support simple life you see simple life start to emerge like single celled things but then it’s millions billions of years before the single-celled things turn into multi-celled things so like Carl said it might be the case that single-celled life is easy to make and can be found but that the progression to multi cell life is very difficult and and maybe not driven in some way it’s as an accident so that not really an answer but we don’t really have an answer and you’re not the type to speculate you have an angle to get an answer if you can measure the atmospheres of enough planets and see how common these oxygen features really are then maybe you can start to say well life could be no more common than this or as common as that I think a large sample does a lot for helping to understand what’s happening well going back to then how non scientists like me approach astronomy the idea that you can tell what’s in a planet’s atmosphere that that that the light from that planet star goes through that atmosphere and travels through space to your telescope and that there’s information hidden in the light is just this a magical idea right has there been a moment where you found yourself stunned by a realization like that either as you were training to become a researcher or since you’ve started working as a professional scientist that just stunned you like that I would say the first time I looked at Kepler data real Kepler data from the spacecraft so I hadn’t spent as I mentioned a long time looking at crappy crappy data from the ground that was had weather and gaps because of the Sun coming up and telescopes breaking and all of these reasons why I didn’t have good data and then the first and it was in the first week after I joined the cap of Science office we sat down to look at the new batch of data and it was just exquisite everything just looked like a model like this was exactly what they told you a transit would look like and it was a real data and so after years of not finding planets we literally sat there for an hour like that’s one that’s one oh that one’s interesting this one and I was just blown away I was just like this was like the culmination of all of those years it’s just like they’re everywhere so it was amazing anything like that for you call ynv Jesse’s experience with the Kepler mission this was such a great mission the opportunity I had that was similar to that was to be involved in the repair of the Hubble Space Telescope back in 1993 and when it when those images came down and showed that finally things were in proper focus and we could start to see all the things that we had expected to see and that that then led to this fantastic set of Hubble results over the past you know 25 years I’m that that was that kind of moment for me that I realized I you know hit the big time of science what motivates you guys personally to study exoplanets what is it that makes this particular field of science of astronomy so compelling well I think it’s the opportunity to see the diversity of what there I enjoy going on travel or hiking and seeing the diversity that we have on earth all the different environments and the earth is so fascinating and intricate the idea that there are thousands more out there with different kinds of life-forms perhaps that that’s really exciting that that possibility and so if we can just take a step toward making civilizations discover all that extra stuff I would be thrilled for me it’s really the discovery like the exploration the fact that I get to find new worlds you know it’s one of those the this idiom that you hear that you know you were born too late to explore the earth but born too early to explore space I don’t feel that way because I’m exploring space everyday I’m finding new planets all the time and there are new worlds and each one is unique and interesting so for me it’s just it’s like that hit of dimpling it’s like another one another one another one so I think it’s fantastic it’s fantastic so we wanted to talk a little bit I know about about letting how other people can be involved in that process of discovery even if they’re not professional scientists the whole idea of citizen science and there there are some ways that you wanted to talk about about how citizen scientists can help with the discovery of exoplanets what is what is that right so so looking for transits around stars I told you you’re just looking for dips so we have software that can do that we have codes that we write to look through all these stuff that light curves and look for the dips but software is not infallible it’s not perfect what’s really good at finding dips is the human brain so we’re excellent at pattern recognition was the reason why we knew the difference between a tiger and grass right like being able to see those stripes was important so we’re excellent to pattern recognition and I can teach you in less than five minutes how to find planets using the transit method so there’s a few different websites that you can go to launched hosted by the Zooniverse platforms universe is a citizen science online program where scientists can bring their data and then citizen scientists can come and help them analyze it so there’s two different exoplanet programs one is called planet hunters and one is called exoplanet explorers exoplanet explorers was k2 data planet hunters was kepler daughter and test data so if you’re interested in going and looking for these transits so the k2 138 system that I showed the musical system was discovered by citizen scientists they found this amazing incredible resonance system which is so rich so I encourage you if you’re interested to go home tonight and go to planet hunters org and start looking for planets around test data because we need your help yeah well there’s a 10 million stars or so that that test will be monitoring over its lifetime yes so every one of you could go adopt a star and see if it’s got a planet or not so as you can see as you’ve heard there are all kinds of ways that you can you can get involved learn a whole lot more and even explore some of these planets and and what they might might look like I think this is a good place for us to hear from you and the audience though now and transition to your questions so we’ll have a microphone down front and if you have a question please come on down and give us your question and then we’ll get a few of the questions from YouTube in here as well so hi there go ahead hi how are you guys tonight how do you first I want to thank you both for a great lecture not only that but also your continued work it gives me something to look forward to always the data you guys give it back but I guess I’d like to combine two things you were at the beginning talking about how you named stars and planets that you find and then you just mentioned that I might be able to find some I was wondering if I can name one Jeff you can give them unofficial names and a lot of them actually do have unofficial names so the first one that we found that has the pure density of pure pure water we call it Kevin after Kevin Costner Waterworld so some of them do have nicknames so I will find one where Jeff is appropriate thank you guys very much how’s it going thank you for a great talk I had two questions the couple together given detection from the transit method if some other civilization somewhere out there is looking at there would be a good chance that they might reciprocally detect us via the transit method and so the question I had was a test question of the four cameras that are displayed on the 13 shots they have the pol gets imaged 13 times and in the north Northern Hemisphere and southern hemisphere we’re skipping the ecliptic and if anybody is going to see us they’re gonna see us along the ecliptic aside from k2 data scanning the ecliptic and plans for TST and torching sensors with the Sun and the and the moon what is the main reason for not scanning the ecliptic because wouldn’t that be the neighborhood we want to look at to find fine friends sure so actually said the prime the prime test mission the first two years is doing it as you said the southern hemisphere and then the northern hemisphere and the reason they they kind of skipped the ecliptic was because they really wanted to have that overlap region at the poles so that they could look for longer period planets down there the extended test mission there’s no reason why the test spacecraft has to stop after two years in the orbit that it’s in actually the moon keeps it in the orbit that it’s in so it doesn’t need any fuel unlike Kepler which ran out of fuel recently so in the extended mission there is a proposal which still has to get accepted by NASA for them to turn those four cameras sideways and do the ecliptic in a few chunks so we are trying to get back to the ecliptic it’s just for the first two years we wanted to get that coverage at the poles those poles are also the James Webb Webb continuous viewing zones of planets we find they will be able to be observed by James Webb all the time okay and the companion question is what are your thoughts on Drake’s and new exoplanet data and where the numbers kind of sit the Drake Equation oh the Drake a 2’s right so this is something that is important to the Future missions and estimating how many plants you might see is what’s the frequency of them so I mean jesse has really been one of the leaders and telling how much Kepler was able to add to that question I should really defer to your answer I need the new answer I always ask you the the we’ve assumed about a 25% frequency for rocky planets in habitable zones when we’ve been planning the hab X and Louvre our mission I so some reanalysis of the Kepler data is showing some smaller numbers some is showing some larger numbers but that’s sort of the first step in the Drake Equation that you’ve referred to is you know how many stars are there like the Sun how many of them have planets like the earth at the right temperature how many of them have the right composition how many of them have life develop and so forth we don’t know how to answer some of the terms in that equation but the ones at the start we are really answering scientifically now yeah thank you so my understanding is that both the transit method and the the Doppler where you look for the who is is a highly biased toward edge on it has to be edge on systems you’re looking at but my understanding is the image message that you’re hoping to do could look at a system that is not edge-on correct so what is the expected gain how much how many more systems would you see at a given distance that are I mean just what is the geometry in terms of of how many more systems you would see right well so the 25% number that I gave for the frequency of rocky planets in a habitable zone that came out of Kepler it already includes a correction factor for the fact that the Kepler could only see the ones that were in edge-on orbits so we’ve gone from a much you know lower detection rate of Kepler to an estimated detection at all inclination angles of 25% you are right that the imaging missions can show us the planets and the entire system at once without waiting for them to transit and for any inclination of the orbit so that’ll let us really investigate our neighbors more fully than the transit method can yeah but it’ll be limited to shorter range is what you’re saying so would you say neighbors yeah that’s right I mean with the transit method it doesn’t really matter how far away the star is just has to be bright enough to give you enough signal whereas in imaging if the system is twice as far away then the planet appears to be in a smaller angular separation from its star so it’s harder to do so imaging is the nearby system approach thank you United States the further way that star is the further you have to drive to see your spotlight yeah it strikes me that much of the exoplanet research is is based upon finding life on other you know other planets assuming the same chemical properties as on earth do you think that’s necessarily so I mean even even on earth four billion years ago I would the the atmosphere was Tod would be toxic to us so how are we going to I mean you can have like silica can make self-replicating crystals of itself which could be construed as life right so I’m curious as to ask your biological research into other chemical pathways that life could follow that doesn’t rely on the same chemistry that we do for instance Titan with its methane lakes like could you have something that lived in that in terms of how we look for that because it’s such an unconstrained problem we don’t really have plans to like design missions to look for that kind of thing because we don’t know what we’re looking for you if something if something emerges on our studies that we’re doing at the moment we’re like here’s another critical pathway where you could have some kind of you know it’s all about energy gradients right if there’s something that works if there’s some alternative biology that works that can give predictions we can go look for that but at the moment we have no predictions and it’s hard to go to NASA and say please give me money to build a big telescope but I don’t know what I’m looking for yet but I know it when I see it I’m sure it is let’s take a question from the YouTube audience blacks and asks us what is the most distant exoplanet ever detected are they all in our galaxy or there was a claim of one of them in the Magellanic Clouds a claim of a micro lensing event in another galaxy but it was fairly dicey dicey is the word I would use so the most distant planets we found are actually towards the middle of the galaxy and that’s using this method that I just mentioned the car mentioned the micro lensing method which is you need to have basically from our cleansing director you need to have this back on the screen of stars and then a star in the foreground it has a planet around it and then the movement of this star on the background star you can work out that there’s a planet there so we need to be looking towards the center of the galaxy where we have this big background screen of stars to find these so all of the most distant star distant planets that we found which are in the like hmm about ten thousand parsecs I think is like the farthest one away we found our all towards the center of the galaxy ten thousand parsecs and light-years like that means anything to anybody but our second between here and the alright hi there okay I guess it connects a little bit to what you just said the the microlensing you’ve been talking about you sort of promised to maybe explain a little bit more about it I was just wondering what the technology there is in compostable opposed to what we had before and is it already developed or is it is there tests that have you have you shot something from Earth is it possible to see it somewhere is it even possible I mean I don’t understand how it works completely micro buzzing technique is another way of counting planets it uses the same kind of measurement as the transit method where he watched the brightness of a star for something to change but instead of the planet passing in front of the star I’m blocking some of its light now what’s happening is for a very distant star and a planet in between the planet passes in front of the star in actually gravitationally magnifies the star according to the theory of general relativity I mean how do you capture it is it so you just very patiently take image after image after image staring at a very dense field of stars and you’ll see some star whose brightness slowly starts to go up and then after the lensing is finished it starts to go back down and then if that foreground star has a planet around it there’ll be a little blip that lasts for a day or two where the planet lens is the light of that distant background star so these are great for telling us how many more planets are out there it’s it’s also though frustrating because once the event is over it never repeats so you could never go back and study that planet again and get a spectrum of it for example but nevertheless this has got you know such promise for explaining how many kinds of planets there are out there that w first emission is going to do a lot of this when it launches in the mid 2020s so exoplanet study studies in general involve a lot of staring and waiting one patch of sky that’s what Kepler did right I mean it you just pick they picked a patch of sky why do they pick that particular direction to look in with Kepler oh that’s a good question so not that your other questions have been good precedent so it was a balance they had to trade having enough stars so that there was some chance of some of them transiting so as we’ve talked about there’s a lot of stars that won’t have transiting planets cuz they’re just not lined up the right way so you have to survey hundreds of thousands of stars to have a good chance of finding the ones that are lined up the right way so it’s an inefficient survey mechanism but if you get too crowded if you’re staring at the Galactic bulge then you have many stars along the same line of sight and you don’t know where the planet is and it’s very confusing so we had to kind of get a little bit out of the Galactic plane but not too far so they chose this specific field of fuel to balance that there were two hundred thousand stars there that were enough but not too many another question from our YouTube audience Gary Hampton asks have we noticed patterns in the materials exoplanets contain in certain systems are there I think that’s asking about the composition right well certainly in terms of density there have been patterns that have been seen yes so one of the interesting things we found the super-earths that I was talking about there actually seemed to be two kinds of super Earths the ones that are more rocky and the ones that are more volatile rich they have things more like Neptune or Uranus and why some planets end up becoming the the smaller ones and why some of them end up becoming the bigger ones is still a mystery there’s a bunch of different theories about why a planet would decide to shed its atmosphere and get us to become small rocky or hold on to a bigger atmosphere so that’s one of the questions we’re trying to answer the other thing that’s really interesting that we’d really love to know for jay diversity some planets we looked at a cloudy and some of them are clear so when a planet is cloudy it’s hard to see into its atmosphere so this transmission spectroscopy this backlit spectroscopy that Kyle was talking about if there’s just cry the atmosphere and the atmosphere is just opaque and you don’t get to see anything in there and so far it’s been hard for us to predict which planets are gonna be cloudy and which ones are gonna be clear so there’s a lot of work going into trying to see if there’s a pattern because if there is an underlying pattern we know not to point j2 as tier the cloudy ones will point about the clear ones yeah having more spectra is really going to help answer that question if we only have a couple dozen planets with spectra right now it’s hard to see patterns in a sample that’s small so ask again when we’ve got a couple hundred there’s also if I’m not mistaken there’s a there are patterns in in the stars in the composition if we’re talking about composition this the compositions of the stars that have the planets that can help you predict some things about the planetary system right yes so actually this is very relevant to my interest because I just put in a proposal today to the NASA test mission to look around the most metal-poor stars so stars have a certain amount of heavy elements in them mostly their hydrogen and helium but they have some heavier things in them too but some stars have a lot more of that than other stars and we think that the amount of heavy elements that a star has in it might be related to how many planets that can form so stars with a lot of heavy elements might be able to form more planets because there’s just more heavy stuff in the disk that the star and the planets form out of but no one’s been able to study the very most metal-poor stars but tests because it’s doing almost the whole sky is looking at tens of thousands of these very metal-poor stars so the proposal that I put in today was to let me look for planets around those because if we find planets around these stars it’ll be you know like a bus coming through these theories that says you can’t form planets around them and I love that kind of thing well there are it was evidence already for stars that have a lot of metal in them that has elements other than hydrogen and helium that they have a more frequent occurrence of giant planets like Jupiter this was found from the early studies with a radial velocity method in the 2000s so there’s a very definitely this trend that the the stars that have more metal content seem to have more giant planets that’s my while that is fascinating my favorite take away from tonight is the fact that astronomers refer to everything heavier than helium as metal well look at your periodic table okay so we have one more question tonight and it comes from YouTube it’s Gary Hampton who asks do we know about exoplanets that are close to black holes and I’m actually going to add on to Gary’s question because black holes are dead stars I do we know about black holes or any kind of you know star at the end of its life or a dead star well that refers back to this slide that Jesse showed with the the different choices for the first exoplanet in 1992 radio astronomers found that a pulsar which is a dead remnant of a supernova explosion from a massive star was actually jiggling around because it had a planet around it that seemed to be roughly the mass of the moon and it was even a second planet or asteroid like object that was detected just from watching how the radio signals played out so not a black hole but something pretty close to it the dead remnant of a star having a planet searches of other neutron stars and pulsars have not found that this is very common and I can’t think I’m scanning my brain I’m scanning my mental NASA exoplanet archive I don’t think we have found any that are in any way associated with black holes unfortunately we haven’t found them but are they are they conceivable there is it possible for a for a system to have a black hole with planets interesting so when the star gets to end of its life and go supernova and collapses down into a black hole if there were planets around them what would happen to them so I think a lot of them would get blown away by the supernova explosion there might be remnants left behind the question about these pulsar planets is whether they’re leftovers of the original planets that were there or whether after the explosion some matter in the disk re coalesced and reforms like second-generation planets so there could be second-generation planets around black holes they would be incredibly difficult to find black holes are notoriously hard to find you know there’s no transit method with black holes yeah I think that’s all the time we have for tonight thanks to everyone for being here and for watching online and of course to our speakers please join us again next month for a look at clouds and their relationship to our climate so we’ll see you then good night

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