New Documentaries 2018 Technology How is Changing Rapidly Beyond The Future [Best Documentary 2018]
To the moon what do you think jack was Jack what, do you think Jack, we'll. Find some other places out there there a couple of other places right. We'll. Learn the directive, I'm signing today will refocus America's. Space program on. Human. Exploration, and, discovery it. Marks an important step in returning, American, astronauts. To the moon for. The first time since 1972. For, long term, exploration. And use this time we. Will not only plant our flag and leave our footprint, we, will establish a, foundation for. An eventual mission to Mars and perhaps. Someday. To many, worlds. Beyond. What. The new policy directive, does is it places a greater emphasis on, the moon as a next step beyond, low-earth orbit, I think it's time for us to move out get flying again engage. Our partners engage, our international, partners and, look at the ways and we can do things differently and still get these missions done we've got a lot of people that want to help us here this is very different than, what happened in previous, major space efforts war was really just government's we want us industry, to be leading and we, want to do it with our international partners, we've. Been such great partners on Space Station the. Space Station courses are a preeminent. Testing, ground right now for anything we want to do is this the first stop and low-earth, orbit we're using it today to test technology, so we're using it today to get the human research done we're, also using it as a enabler, for our commercial partners today, we need to train a new generation of, explorers to. Be able to operate in deep space SLS. And Orion of course is going to be set up not only to just do the, as it. Was trying to be extensible to Mars we don't wanna lose that horizon go so we go forward and the, moon is the next peaceable step Mars remains an inspiring horizon bold that we need to be working toward but. We first need to walk out of the neighborhood before we can run. This. Is Hubble telescopes, famous, photograph, Hubble, ultra-deep field. There. Are nearly 10,000. Galaxies, each containing as. Many as a hundred billion planets, in this image alone, but. The question has always been out. Of those billions of planets how, many could have life. Observing. Earth's global biology. On a massive planetary, scale has, given scientists, the tools to answer important, questions like. How. Can we use these models of our own planet to detect signs of life on other worlds in. Short. The, first thing that we're going to do is figure, out how we'd find ourselves. When. I talk to people about this about the search for life on all, these planets we found around all these other stars a very, common, response I get as this line, from contact, well if there isn't anything out there it would be a horrible waste of space which, is wonderful a wonderful life, and especially, was a wonderful line 20 years ago but, now we're beyond that that's, dr., Shawn Donegal Goldman, he's. One of NASA's many scientists, heading up the search for life I'm a research, space, scientist, and astrobiologists, at NASA Goddard Space Flight Center what I do at NASA is I look for ways to look for life on other planets. 10. Years ago conversations, about life in the universe were mainly limited to bartók and philosophical. Conversations, but. That's all changed, we. Can now apply the scientific, method to. The question of are we alone we, based. On our understanding of how life operates on earth are starting to derive principles, of the signals, that life creates, that, we could then look for on these planets around other stars, but. With the universe as fast as ours where. Do you even begin looking, for these earth-like planets. NASA. Scientists, must take an extremely, calculated. Approach when it comes to combing the universe for signs of life, by. Studying Earth's climate over its long history we. Have a pretty good understanding of, how climate operates, on other rocky planets and, that. Gives us some helpful clues on the distance from a star and the size of a planet that could Harbor a global, biosphere, like the one we have here on earth, it. All comes down to knowing where to look we. Have a concept for this it's called the habitable zone the Goldilocks zone and the. Basic idea is you can't be too hot because. Otherwise you'll lose your oceans they'll basically boil, and steam away it, can't be too cold because then your oceans will freeze over you, want that big sort of global, ocean, reservoir at the surface which happens when you're kind of in the middle and just right in. Our solar system the. Goldilocks, zone is found by Venus which is too hot and steamy with no oceans at the surface and Mars, which is too cold and too small and size, matters too, to.
Give An example the moon is technically, in just the right place it's. In the middle of the Goldilocks zone just like Earth is and it gets the right amount of energy from the Sun, but. It's too small to hold on to an atmosphere and. The. Same thing goes for planets, that are too big like gas giants, where there's too much pressure bearing, down on liquid water we're, on the Goldilocks planet and what's. Really neat is we found a lot of other so-called Goldilocks. Planets, in the last few years that we could then think, about looking for signs of life on in the future the. Study Sean is talking about have been coming out pretty consistently, since the early 2000s, the recent uptick, in exoplanet. Discoveries. Over the past seven, years or so is due in large part to the Kepler space telescope which, found over, thousands. Of exoplanets orbiting, other stars one. Cluster of planets after another, astrophysicists. Have discovered a mind-blowing, number of worlds, that are the right size and distance, from their star to, potentially, have conditions, for life similar to earth the, most amazing thing that Earth has taught us is that life can really exist, in very, dramatic environments. From really. Hot environments. In the middle of a desert to really, cold environments. With little light at the very bottom of our ocean, based. On what we know about Earth the, fundamental, cocktail, looks like this you. Need liquid water the, right atmospheric, gases and if you're lucky specific. Global signs of life. Everywhere. We look whether it's a desert or Antarctica. Or the deepest parts of the ocean or. The deepest parts of Earth's crust that we've explored, as long. As there's a tiny speck of liquid water there's, life and. Because. Of that it's been central to NASA's search for habitable environments, elsewhere. It's. Why scientists, get excited about water spewing up from the icy moons of Europa, and Enceladus in, our outer solar system not. Only could they have water but, they could have global, oceans, like the ones we have here on earth. After. Liquid water we look for atmospheric, gases actually. The gas we're breathing now oxygen. Find. Oxygen and methane together, in the same atmosphere and, you've, got something special there, are ways to build up oxygen or methane, in the planetary, atmosphere, but, the only way you get them both in the same atmosphere at the same time is, if you produce them, both super. Rapidly. And the, only way we know how to do that is through, life.
The. Next thing scientists, could look for it is pigment, the, colors of life like. The chlorophyll, found in plants on land and, algae, and phytoplankton in, the ocean, although. There aren't currently any outer space missions in progress to retrieve this data we. Could in theory be able to detect similar, colors on a planet, around another star in the future. But. Maybe one of the coolest, things about this whole enterprise is, how, quickly we're learning I firmly. Believe that one. Of two things is going to happen in the course of my scientific, career either. We're gonna find evidence that we're not alone in the universe or we'll. Have so exhaustively, searched, for it and not found anything that will, know that the universe is a lonely place and that our our place in it is more special because of that either, way I can't, wait to find out what we uncover in the next 20 years. This. Is sort of our classic cartoon, picture of the solar system, with. The now eight classic, planets and we, were sort of taught in the 1980s, that we. Have these small rocky planets on the interior there is earth Mercury, Venus Earth Mars Jupiter Saturn Uranus and Neptune and the small. Rocky planets form, on the inner part of the solar system and then all of a sudden out past about two three times the Earth's Sun distance you, start getting these worlds, that are dominated, by the ices, things like water and ammonia and methane the so called astronomical, ices carbon. Nitrogen and oxygen with, with hydrogen's, attached and. Also. A lot of hydrogen helium Jupiter, and Saturn were very much dominated by hydrogen helium and each of them had their own little system of moons all the moons were interesting. These small cratered worlds some of them had active geology couple. Them have atmospheres, and. So. The. This was sort of our classic, picture of the solar system through. About the 1980s. Shortly. After they were finding the there, was discovery of the the Kuiper belt past, Pluto, we now know there's there's icy worlds out there and there may even be another planets, the whole planet nine it, would not surprise me of that was discovering the next year, or two the dynamical, evidence looks pretty interesting. So. One, of the great I would. Say victories of physics and astronomical. Astronomy. In the 20th century is this sort of comprehensive picture of the. Formation, the evolution, and death of stars we understand, stellar, structure, very well the stellar atmospheres. If, you, could sort of stand, back and look at our galaxy over a timescale of millions, of years billions of years you would see stars being formed living. Their lives and being snuffed out through various means, and this is just showing the the the evolutionary, pathways, for, small. Stars like the Sun they're. Born in these dark. Molecular clouds let's talk about these a little bit more later they. Collapse, basically. This is the widest, stars form, stars. Are forming in the gas and dust in it. Floating around the galaxies it's where gravity wins, out over gas pressure and magnetic field pressure it's, a very inefficient process okay only a few percent of the mass in these clouds actually form stars and then, only a tiny fraction the mass that is in forming a, star, wind up forming, planets so. Our son will live a nice happy life for about ten billion years or about halfway through at. The end of its life it'll become a red giant it, will exhaust its hydrogen fuel and it'll furiously. Change its inner structure, to try to heat to higher temperatures, to to. Burn, other sources. Of fuel it'll run out and eventually, it'll turn into a planetary nebula it will blow off its outer layers so. This is going on this this this whole time scale here is about twelve billion years and for long for, low mass stars, in. The galaxy stars even down to the mass of the Sun some of them have had time to go through the cycle the. Massive, stars the big bright white blue, blue. White stars you see in the night sky. Those, live very short lives these are stars are typically ten or tens of times the mass of the Sun they, correspondingly, live very, short lives maybe tens of millions of years and they. Go through a much more destructive, phase at the end they actually explode and depending, on their mass they'll turn into either a neutron star or a black hole but. What doesn't go into the neutron star in black hole contains a lot of metals and a lot of stuff that turns into planets and turns into life and this, process is constantly, enriching, the gas in our galaxy our galaxy, is slowly getting, full of, so-called. Metals. So. Here's the periodic table of elements you're used to seeing that you learned in your, chemistry class most. Of the normal. Gas. In the in the galaxy is hydrogen and helium up here elements number one and number two there.
Are About 98%, of the, the. Amount. Of normal matter in the galaxy we're excluding so called dark matter and dark energy that's for another talk all the. Rest of the other elements are less than 2% okay. If you averaged out over the galaxy but. Those are pretty important because they end up turning into planets and turning into life now. The astronomers, this is the astronomers HR, diagram, hydrogen. Helium metals. Okay. All the other ninety plus I think we're up to 118. But those, are short-lived but the other ninety or so stable elements, the. Astronomers just call them metals and they tend. To track, each other in terms of their relative abundance with respect to each other so, we talked about the metallicity, of stars in the metallicity of the galaxy and the. Amount of metals in the galaxy is slowly, getting higher, over time because stars are and dying and they're returning this. The. Products, of the nucleosynthesis. And the stellar course returning. It to the galaxy, now. What happens to that stuff there's all of our metals well. Here's a typical nearby, nebula, this is the Orion Nebula. This. Is a very. Beautiful nebula bout a thousand, light years away there's, a few thousand, stars that are forming in this gas and so what we're seeing is baby stars less than about a million years old that are condensing, out of this gas and the, very most massive, ones are have. Already turned on they're already burning their hydrogen they're, giving off a ton of ultraviolet, radiation and they're blowing, away the gas those, high mass stars are actually destroying. The nest that the stars are forming out of. Well. If you zoom in on that nebula here's some Hubble Space Telescope, images and this is amazing what you're seeing is baby pictures, of Suns these. Are all little stars forming, and you'll. Notice if you zoom in they look like little blobs and, we, know the distance to Orion and we can measure the angle, that. Covers. These little blobs and the answer the size, of these blobs is only on the order of a few hundred times the. Earth-sun distance okay. So, they, they're. Talking, about solar system scales here okay, so these are so called proplyds or protoplanetary discs, and they're fascinating, you can see some. Of these look very dark what you're seeing is this illuminated, nebula behind it and the. Gas and dust that's forming in planets, around these little stars is actually blocking out the light behind. It there's. Hundreds of these this, is one star formation region our galaxy this is the Orion editor there's thousands, of them okay. This is going on right now so. Stell. What star formation is going on there's, supernova, there's we see planetary nebulae we see the yet we see evidence of stellar death so there's this sort of birth. And death of stars going on and we see during. Stellar birth we see the ingredients, for forming planets. Okay. So that's great we've seen some disks. Around baby stars we know that there's metals, there, there's material for forming planets including. Things you'll find in your vitamins and in your food that life. Likes so. How do we discover and characterize planets, why are they so hard to find why did it take until only a couple decades ago to find planets, well. A few of the hence were actually. Teased. Out here, in the in the 1980s, this is a satellite called I rafts that was, launched in 1983, from Vandenberg this. Satellite. Did an infrared all Sky Survey and, it found a few surprises, so. One of the things that found was that a handful, of the nearby stars actually had big infrared excesses these, stars were giving off way more infrared.
Light Than they should be okay so we know what the the distribution, of energies are for stars, and how, much light they should give out in the infrared there, was a certain class of stars was getting off way more infrared, light and it was actually a group. Here. At JPL. And in 1984. And at University of Arizona there. Was this great paper by Smith. And Richard, Terrell Brad Smith Richard Terrell and they. Actually went to a telescope in Chile and they, decided to look at one of these stars with, a chronograph they blotted, out the light from the star and they, took a deep image of it and lo and behold they. Saw this stuff, on both sides of the stars okay. This. Is actually this. Is what was responsible for the infrared light that this is ground-up dust grains orbiting, this star beta, Pictoris which, we now know is pretty young is the star it's about twenty or twenty-five million years old and, this, was sort of this is one of our first hints that there was planets there because if you see this dust it should get blown out by the star's light in a very short time maybe hundreds, of thousands to millions of years so, there had to be some population, of things grinding, up asteroids, comets etc, that, we're creating then we're kicking up this dust so. This ended up being actually, nearby a, baby. Solar system so, things were starting to get interesting I remember seeing this story when I was in elementary school and that really. Sort. Of made it clear that we're. Kind of getting to the point where we're gonna start finding these planets soon so, how do we find planets okay, well, you think you could just take an image right you take your telescope, you look at the star if you squint hard, enough you may see a little dim dot next to the star this, is really tricky okay there's a there's a few complications, one is, just, the planets themselves or, only a planet, like Jupiter is only about 1 billion is bright is its star okay this, is in the reflected, light so that planet is the Stars giving off light the lights hitting that planet and then that likes being redirected to us and. The, ratio, is about one in a billion it's it's even fainter for a, planet.
Like Earth well, this is very challenging the. Other problem is that planets tend to be if they're on the same scales our solar system if there's several astronomical units the stars are so far away that, the angular separation, is, very very tiny so. The, star is right, up against the sort. Of the planets right up against the star and, so. You actually need to you. Need to you need to do something to the star's light because, the other problem is we're, on earth were, at the bottom of an atmosphere, and that atmosphere plays. With the light right. The stars twinkle, the stars are twinkling because there's these little variations. In the temperature and humidity of, the air and the, light waves that are going through the atmosphere, we're going round a little bit and so they blur out the star's light and don't completely swamp the poor planet so you can't just go to the telescope look through it and say oh I see a planet next to the star you actually have to blot out the star's. Light or there's, a few other tricks I'll show you later okay so, this is so-called direct imaging. One, of the one of the ways to, find planets that's been very popular for decades, and still, has unfortunately. It. Still shows promise, but has not borne much fruit I'll put it that way is so-called, astrometry and that. Is looking, for the wobbles of the star due, to a planet tugging on it okay, so. The planet itself is pulling, gravitationally, on the star we, think of the planets orbiting the Sun and the Sun is at the center of the solar system that's not quite true there's, something called the barycenter. Jupiter. Is the big. Source. Of gravity that's tugging on the Sun and the. Sun actually moves. Around the inner solar system a little bit on the timescale similar to Jupiter Jupiter's, orbit it's, pretty gradual it's on the order of hundreds of kilometres, of thousands of kilometres but it's something if you're far enough away if you measure the position to start accurately enough you should be able to tease out that signal but, it's very, tough so, this, is just showing how you would use multiple, stars if you could actually accurately measure the angle between the, star with the planet these other stars over, time you might be able to see the little bumps and Wiggles of the stars position, and tease, out the planet. This. Is the one, of the first techniques that ended up being very fruitful. This is so called Doppler spectroscopy, or the radial velocity method so what we doing so, you've got your planet orbiting, the star it's tugging on the star the. Stars moving. Around and as it's moving around its velocity is changing it's moving towards you it's moving away from you okay so, the light is being Doppler shifted it'll be blue shifted if it's moving away from you it's red shifted it's moving away from us now the, planet, is not. That massive compared to the star it's a very very subtle signal, okay, if we're, talking about Jupiter pulling, on the Sun we're talking about a 12 meter per second signal over 12, years okay.
12 Meters per second is about as fast as Usain Bolt, goes in ten seconds, okay. Very. Slow if we're talking an earth-like planet we're, talking about 10 centimeters, per second which is how I would run next, to the same Bowl okay. Very, very slow signal okay so this is just sort of generalizing, we don't see the colors changing red and blue when the things are moving near the speed of light you actually see a color shift we see that with, quasars. But, this is a very subtle signal you're looking for you're looking at the spectrum of the star and the lines are moving back and forth very. Very tiny amounts, so. This is the so called Doppler spectroscopy, technique and there's been many hundreds of planets found through this technique the. Technique that's been very fruitful, for the last decade and a half is the so-called transit method okay this is what happens what a planet passes in front of its star now, the trick, is you need to measure how bright the star is very accurately okay so, here's time here's how, bright the star is if. We got a star like the Sun over, time it only varies at about the one part in a thousand, level over a long time you might see some star spots appear here and there that make some little dips but, if you, have a jupiter-sized, planet, pass in front of the Sun you'd. Get a dip of about 1% okay. Now we're talking we can measure 1% dip for a lot of the brightest stars if, you get a planet like the earth which, is another factor of 10 smaller. Than Jupiter and it's, area, is another, factor of a hundred smaller we're. Looking for a signal that's one part in 10,000. Okay. That's getting tough it's, very difficult to do from the ground it's difficult to measure the brightness --is of the star's dad accurately, from the ground but if you go to space, voila, now we're talking about discovering, earth-like planets so I'll talk about the Kepler mission here, in a bit the, Kepler mission has been responsible, for finding most, of the planets that have been discovered now we're talking thousands, of planets so, this is a great technique. This is just another movie showing differences, in the sizes so if you had a large. Planet, let's say a jupiter-sized, planet, and earth-sized planet you'll just get you'll get different. Depths. In, the in. The white curve okay so get roughly one percent signals, for a jupiter-like planet, and about a one part in 10,000, signal for an earth-like planet. Now. The, other thing Kepler, has been finding, is multiple, planet systems okay, there's actually been systems, seen now we, we, have a great. Vantage point we happen to see multiple planets, passing, in front of the star if you're really lucky you start to see gravitational, perturbations the, planets are pulling on each other and we can interact as. Masses I'll show a plot later, in this talk, exploiting. That technique. To, measure some masses so Kepler, has found some very interesting multi-planet. Systems and there's. These. Have been very interesting because we can it's, easier to get the masses of those planets this. Is another technique called micro lensing this, has been. Put. To good use over about the last decade and it's now going to be a primary, means of finding planets for. One, of the means of finding planets for the for the upcoming W first mission so. You, have, your telescope, down here and let's say you'll have a background star but something passes in front of it let's say some mass let's say a star or a planet as it passes in front the. Space-time. Is curved okay. Light. Is not following straight lines you think a light beam is gonna follow a straight line the. Light is following a straight line in four dimensions oh god here we go we're going into n Stein, what. From our perspective, is our. Three, dimensional beings, passing, through time from our perspective, that, straight, line looks, curved and and. The mass actually acts like a lens you'll actually get the light from the star bend. Around that mass and focus. And, what. You get is an enhancement the amount of light so this is time and then this is the brightness of the star so, you'll get these characteristic. Curves and if. This thing that's passing in front has a planet, you get an extra little curve on top of it okay so you may get this curve and you get another little one and this, technique so far has been sensitive.
To Very small planets, we're talking things down well. Below this the size of Earth now. The trick is this doesn't happen all the time you need - stars - lineup so you need to look at many many many thousands, of stars with millions of stars and so W first is gonna be surveying the center of our galaxy I showed, you that picture at the beginning of our the, center of our galaxy some. Of the richest star fields in the galaxy and then if you start looking a lot of these statistically. Statistically you'll. Start picking these these, events up. So. I, showed, you that there, was the detection of that dust around beta Pictoris in 1983, with the i-raths satellite things start to get interesting around 1989, this, is the star HD one one four seven six - these, are our lovely stellar, designations, okay. Stellar, designations, are the phone number names, this. Was a giant planet orbiting, in about 80. Days roughly, at about the same distance mercury, is from its star but, this planet, is about 11 times bigger than Jupiter we. Don't know the inclination of the system we don't know how elton is because it didn't pass in front of its star but. Around 1989. This. Star would start was being, used as a standard, when, they were measuring the velocities of other stars they kept coming back to this one as a. Useful ruler, of how fast the star was moving and they noticed that this this, standard, star itself was moving at the hundreds of meters a second level so. There was this nice paper by Dave blazing from harvard-smithsonian, Center, for Astrophysics and, they. Said well this could be a failed star it could be a planet and back in these days it was a little voodoo to start saying you detected. A planet. But. As we look back now this could be the first planet that was actually, detected, this this one is real, things. Got really interesting around 1992, this was 25 years ago this week hard, to believe January, 1992, there, was the discovery of three. Planets, around a pulsar so, what's a pulsar this, is the remnant of a massive star that's undergone a supernova, and all that's left is this huge. Mass. About the size of work about the mass of our Sun but packed into about 10 kilometers okay, so, roughly the size. Of Pasadena, but. With as much mass as our Sun okay it'd, be it wouldn't be not be a very nice place to live okay, the, whole thing is made of neutrons okay. There's so much there's. So much pressure there the protons, and electrons themselves have actually fused, into into, neutrons so it's essentially a gigantic nucleus. Well. It has a huge magnetic field and it spins rapidly and it gives off these radio waves and those radio waves can be picked up by astronomers on earth and lo, and behold this new pulsar called, be 12 57 plus 12 also.
Known As Lick now it has a new I you name, this. Object was moving back and forth the timing, of the radio signals was changing, and it was fairly complex, because lo and behold was three bodies pulling on it so. These. Two outer ones would and. I can't remember the original letter at the ridge there's letter designations, BCD. For these I like them there's the new I you names these are easy to remember now poltergeist. And Ron are these, two were about three times the mass of the earth fo'get. Or is very small, it sits on the order of the size of mercury or sub so these were very tiny planets, there was no other effect they could think of that could replicate this, this. This. Variation in the pulsar signal so this was really the first rock solid evidence, I would say of, extrasolar. Planets, and. Again that was 25 years ago this week. Around. 1995. The. Things, got interesting. Again this was the discovery of 51 peg, B. This. Was a hot Jupiter this is a very unexpected signal, there was the 51, peg is a very, sun-like, star it's a yellow main, sequence star like the Sun. Sort. Of middle-aged and lo, and behold the, the, star, was moving back and forth at about 100 meter per second level in its orbit and what, you need to do what, you need to explain that is 1/2 jupiter-mass, planet, on a, four day period ok, nobody was expecting this before 1995, because, as you saw from our solar system we had an example of one solar system we don't have any giant planets, within a few astronomical units and Sun there, you, need Isis to form those so. Why would you have a giant planet so close and but. It was it was there it was quickly confirmed by another another. Group in California. So. Right. Away we were starting to see some very strange objects, ok H the the first one I showed you was 10 Jupiter masses this is really pushing. The boundaries of what you might consider a planet the second example was planets around a dead star a pulsar, pulsar planets and then the nesic next example was a Jupiter orbiting, its star in a few days okay we're nowhere near finding, anything like solar system yet by 1995. I'm. Gonna save a lot of history which is gonna make a lot of exit plan of astronomers mad, I'm apologize, if you have left off your planets there's a few thousand of them now and all your missions and all your telescopes, so, we're gonna skip through to what I think is a few interesting cases here. And. Just. Just just to show. You some some interesting, examples. So. The the, Kepler mission launched, in 2009, I'll show you a few plots from from that mission and one, of the surprises, was a circumbinary, planet okay, could a planet actually form out here. Out. Outside. The the the. The, orbits of its stars and the answer seems to be yes and. They're finding many, examples, of these and they're, roughly they tend, to be on the order of a factor of five further, away than the separations, between the two stars is we. Look at young stars we do see examples of pairs of young stars that actually have a disk of material orbiting. Both we see, circumbinary, discs. Of gas and dust that probably form these, planets. So. I'll, be the first astronomer who's given where these talks that does not mention a certain. Movie about a certain, person. That was, bullseye. Womp rats on their. Desert planet, that had two stars I'm not going to mention it. Kepler, also found has found so far. Small. Rocky planets in the habitable zones, of their stars so what do we mean by habitable, zone you. Can start many an argument. Defining. Exactly what the what the habitable zone means. It's. The range of, orbital. Separations. Orbiting. A star where. You could plausibly have, liquid water on the surface of the planet liquid water seems to be the main. Environmental. Constraint. For. Life at least on our planet you need water and so. If. You move a planet too close if you if you took earth and you move it a bit closer to the Sun you, initiate, a runaway greenhouse effect you'd, actually boil off the oceans if you, move the earth too far away the. Earth starts to get very cold you actually start freezing out carbon dioxide up in the atmosphere and you start forming clouds that act like a big mirror and you get a runaway which actually makes the planet colder so, there's sort of a narrow. Range of orbital separations, where a planet can have. Liquid. Water and so this is just a little gallery of the, planets so far out of the 2000. Plus that Kepler has found that happened, to be in the habitable zones of their stars these, are the different types of stars and stars, these is so-called red dwarfs these are the most common types of stars in the galaxy about, three-quarters, of the stars in the galaxy are M dwarfs including our nearest this next, star after the Sun Proxima Centauri k.
Stars Are a little bit smaller typically about half the mass of the Sun and then, these are the G stars like our Sun okay, so we've been finding a lot of these habitable, planets around the. N stars and K stars it's been a little bit tougher for the G stars because you have to, you. Have to trace, the planets further out to periods, closer to a year and Kepler. Had a limited lifetime. For, detecting planets passing, in front of the star so this is this is not indicating, that there's fewer planets, around the G stars simply that the our current, techniques are more sensitive, to the very close in planets around, these lower mass stars. This, was one of my favorites this was in one. Of the first directly imaged. Planets. Called formal halt B, this, is a bright nearby. Southern star it's, alpha Pisces sauce Trina and the, southern. Fish this, is the brightest star that constellation it has a big disk of material about it around, it I was telling you about the i-raths mission in early 80s this is one of the first big infrared excesses detected. With that satellite there's a lot of dust in that system and, back. In 2009. Paul. Callison, and colleagues were looking at images of formal, halt with a coronagraph in place so they were blotting out the bright star here FOMA halts you know in, probably, the top 10 or 20 brightest stars on the sky they, had to blot out the light with Hubble and see, all the faint structure, and lo and behold there was a little dot moving, and this, appears to be a planet orbiting, the star what's. Weird about this thing is it the colors of it look, like reflected, light from the star so. What we may be seeing here is not a Jupiter, or maybe even not even a Neptune we may be seeing reflected, light from, icy. Particles something, like Saturn's, rings or a cloud, of material, orbiting. The star so, the nature of this this objects a little bit nebulous but it's been it's been very interesting but we could be seeing a tiny planet, with a, the ring system around it so. Speaking of rings I want to tell you about. One. Of the projects I've worked on recently, this. Is a object. I won't give you the full phone number because it's horrible this has one of those horrible ashram call names with about 15 digits and we've just been we, shortened it to J 1407. This. Was a nearby young star a few hundred light-years away, it's similar to the Sun but. It's only about 15 million, years old very young star and. We, were looking through data. From a robotic, telescope, that, was monitoring the brightnesses, of thousands, of stars looking for planets and when. We were looking through the data one of the young stars that we were studying back in 2007. So this is time this. Is April and May of 2007. And this, is the brightness of a star okay, one is its average brightness, over a few year period and the, star rotates really, rapidly every three days and it has star spots and so in the course of the day indigo do do, you don't look very by about two or three percent and then. All of a sudden in april/may over about a two thousand seven the star started, behaving very badly okay. We started seeing dimming at the tens of percent level okay, that should that should. Scream. That there's something very interesting going on you just don't see stars turn off okay and it's, dhimmis point the star had dimmed ninety-five, percent, okay. This really got our attention the. Shape of the variations, was even more interesting because it looked like you had to be passing some, structure, in front of the star that might be symmetric, so. We first saw this in December 2010. At. University, of Rochester, my graduate student, who and I remember in December 2010, looking at this plot trying. To figure out what the heck to make of it and. The. First thing that came to mind was how the. Rings of Uranus were discovered, so Uranus has these very faint rings around it, the, Kuiper airborne observatory, was used in 1977. To observe Uranus and Uranus. Pass in front of a star and the star blinked, off and they detected, the rings of Uranus and I. Thought could, this be like that but these rings would have to be absolutely huge very massive the. Bottom is just a zoom in of some of the structure each little clump of points here is one. Night of data okay this is a real telescope a real telescope, from the ground so, you have to worry about things like clouds, and, power outages, and things, like that and so there's lots of gaps in the data okay we only have data covering about 20% of the time here but even during the after the gaps you'll see the star has stilled in tens of percent okay, so, we tried to piece together the story of this star, you'll notice by the way if you look at it there's, sort of this big, inner dip, over a couple of weeks and then, you'll see these these little dips on the side and even in the course of a night the variation, it can vary by tens, of percent this is a really, bizarre object, it took us about a year to to.
Analyze This and come out with a paper that even had a plausible. First. Attempt, at what we thought this thing was this. Is not that first attempt this is about our third attempt okay this is a movie for about 2015. This, is this is the time this. Is the brightness of the star the. Orange, line is a model, trying to fit those yellow, data points the yellow data are the actual measurements, of the star's brightness it's. Not, perfect, okay it does a reasonable, job it probably fits about 90%, of the data and at. Top this is our model of a huge ring system around a companion, we call Jay 1407, little B okay, we're, not sure exactly what this is it's probably a giant planet it could be a failed. Star called a brown dwarf let's talk a little bit about those later. Right. Now we think it's probably less, than tens, of times the mass of Jupiter the, whole system, this whole system of rings you could fit well inside the the orbit of mercury okay, but it's much bigger than Saturn's, rings okay, there. The whole system is about 200, times bigger than Saturn's rings this is a totally, different beast this is not like Saturn's, systems, Saturn. Has a ring. System covers, a few hundred thousand kilometers very, icy particles and they, exist in a region where the, tidal, forces of Saturn would shred the material part in case they try to form a moon I'll say no big moons here okay gravity will tear these objects apart this. System is about 200 times larger and, so what we think we might be seeing is the, material, that would go into forming a system. Of moons around a giant planet or little planets around a brown dwarf I don't even know what there's no word yet for, I guess, satellite, would say satellite around a brown dwarf the. Other interesting thing is we see these gaps we've seen discs before we see district on young stars they can be huge tens it's tens of times your son distance we, don't see too much structure in them there's. A lot of structure in this to explain these dips these, big variations, of the tens of percent level there has to be gaps, in the. Disk well there's gaps why, are why is there dust preferentially, in some lanes and not in other lanes okay so, especially. This one this one really stood out we put ring gap we, could be seeing moon, formation, this could be the first. Indirect. Evidence of EXO, moons, orbiting, exoplanets. Orbiting other stars we. Haven't seen any moons yet all, we've got is this disc but, something has got to be clearing out these these lanes in this disk, we've. Gone looking for more objects like this we keep finding we, found a few discs we haven't we have a system that will be coming out next year, that.
Is Someone. Analogous, but we haven't found one whose structures as rich as this, system. By. The way so, my my, co-author, Matt, Kenworthy at University of Leiden had this cheeky graphic he came up with if you replace Saturn, in our system with this set of rings this is what it would look like during. The day, it. Would be picking off about 1% of the star's light it would be like a huge mirror there's the moon so. How'd you like to come out during the day and see that thing. It, was a slow news day in January 2015. 2015. Was such a nice year compared to 2016. And. So, for, a few hours on CNN, this. Was not fake news this was real news. This, beautiful, graphic was done by Ron Miller hit black hat studios, he's done a lot of space art and I want to mention. That but he had this beautiful artwork. That went with it I'm, doing an experiment with a student. At University of Rochester, to build a robotic observatory, he's building it I'm here hi, Sam. We're. Hoping to build this experiment, to put in Australia, in 2017. And we, want to watch a nearby, exoplanet. Called beta Pictoris B I showed you that disk, system there's, a little planet they discovered in 2009, and this, is a movie of the images of that planet. Over the last time about 2013, to 2015, and as you see it's going to come very close to its star in 2017. It's not gonna pass exactly in front of it but it's gonna come pretty close so, we want to probe the region near the planets to see if there's any evidence of a moon, forming disk like Jay 1407, this system is only a little bit older than Jay 1407, we're talking about 20 million years so, we could be if we're, lucky we may catch a snapshot of a disk passing in front of a star and, maybe see if we can catch moon, formation, in action so. I now work at JPL I'm. Now working, with the NASA exoplanet exploration. Program, its. Purpose does just described. In a 2014. NASA science, plan we're here to discover planets, around other stars characterize. Their properties identify. Candidates, that could Harbor life so. We're supporting various. Space missions and some. Ground-based efforts to. Achieving. Discovering. Planets and characterizing, them, this. Is just a little snapshot of some of the activities that the exoplanet exploration, program does a few. Of the missions here that are that are managed. Are the Kepler and now k2 mission, Kepler, is this is the mission, that's finding all these transiting. Planets, it. Has transitioned, now a couple of the the the gyros, are dead they're. In a phase now where they can only observe certain parts of the sky and they now call this the k2 mission but it's still finding, many, dozens of planets, this.
Is The W first mission I'll talk a little bit about here in a few minutes, there's. Stars development, of a star shade I'll show you an animation of the star shade and then there's lots of other activities including some. Efforts. To characterize. Disks around nearby, stars and measure. Their radial velocities, in support, of these missions. Let, me click on this and fortunately. The sound is off I want to thank Dan. For brookie at University of Chicago this, is the classic Kepler Ori this. These, are the multi-planet, systems that Kepler found every. One of these is a solar system and this is only showing the planets that we could see that happened to be along the line of sight ok. They're. Sorted by size so you get some things that are probably Jupiter, size here all the way down to very tiny things. Approaching. Maybe half the size. Of the earth, some. Of these are three four or five planets, systems and there's a lot of these and we. Can now start to measure masses because these. Planets are tugging, on each other think of it's supposed to and then there, we go. And they're. Sorted by the size of the the size of the orbits okay but, it's amazing and these are very close in systems, so pretty. Much none, of these are like our solar system these are the systems that have planets very very close to their star most of these planets are closer, to the star than. Mercury and, venus. Okay. So that's a dizzying turn away if it's hurting your eyes. So. The Kepler mission was launched in 2009, this has been a phenomenal phenomenally, successful mission, again it's it's in this so called k2 phase now it's it's. Using a limited amount of fuel to look at different fields along the ecliptic along, the path for the the earth. In. The the Earth's orbital plane and. Also. Very, soon the test mission being. Developed at Goddard Space Flight Center it's, going to be similar to Kepler, but it's going to look it's. Going to image the whole sky Kepler, basically looked at one region of the sky it stared at a hundred thousand, stars and. Discovered. About. Five thousand candidates, and we have about 2,000 of those that are that are confirmed. Planets. So. From the Kepler and k2 mission, this is showing the the sizes of the planets that have been discovered along, with the temperature of the host star our, Sun is around 5800. Kelvin here, so these are the yellow stars these are the orange stars these are the red stars we're, starting to find a lot of planets now that are similar in size to the the, earth ok, so the earth size, is a one on here Uranus.
And Neptune or around four, on here, and you'll, notice a lot of these things are intermediate, in size between between. The earth and uranus and neptune. This. Is one of the interesting results from Kepler is, most. Of the planets were finding, does, not have there's, no counterpart in our solar system, there's, planets intermediate in size between Earth. And Venus and Uranus and Neptune and they seem to be very very common. This. Is this was a plot from 2015, showing the distribution of planets these a big jupiter-like planets, here's, the Neptune sized planets, 2 to 6 Earth radii these. Are so-called super, Earths 1.25. - two or three of these definitions you'll see vary a little bit over, over time and these are earth size and smaller okay, now. This could be a little bit biased because these smaller planets are harder to pick out they have cover a smaller area if, you D bias this. Plot if, you take into account that it's harder to find the smaller planets, you, start to get a distribution like this and we. Still have this excess there's, lots of little so-called, mini Neptune's and super Earths for. Lack of better terms here and we're. Seeing a lot of Earth's also. Compared. To the number of these. Gas. Giants and things intermediate, between the size of Neptune. And Jupiter. It. Coincidentally, the the the, hypothesized. Planet, 9 you may have heard of heard about that they're looking for the. Dynamical. Estimates if it's real or something on the order of 5 to 10 Earth masses and so that would actually be intermediate in size, between Earth and Neptune so if there is a planet 9 it, could be part of this this class of planets that so, far we have not seen up close in our solar system but, they're very very common, around, nearby stars. This. Is a recent plot that was. Put. Together on showing, the, masses. And the radii, of these, exoplanets. And I've plotted earth on here one earth mass one, earth radius, here's, Neptune, 17, Earth masses for, Earth radii and here's. A lot of these things that are intermediate between the Earth and Neptune we're seeing a lot of the so-called super, Earths and mini Neptune's these are gas giants up here okay so. Jupiter if you could plot on here Jupiter is about 300. Earth. Masses in about 10 or 11 or radii. So. Jupiter. Is up here in depth oon earth, so. We're finding a lot of these things that are in either that, are intermediate, these, lines, are showing what, if you made a planet out of pure iron ok astrophysically. We don't think that's gonna exist at least far out maybe close in we might get things similar, to that things. That are dominated by rock things, are dominated by ice and when we mean ice swimming the Astrophysical, ices things like water. Ammonia. Methane and if. You get bigger than this line you have to start adding hydrogen helium okay, so you're gonna send Neptune or good examples of that you're innocent Neptune has sort of a sprinkling, of hydrogen helium but, they're probably mostly dominated by ice and rock, earth.
Has A big iron nickel core and a big silicate, mantle. And crust, and just a little thin veneer of water that covers, most of the most of the planet. But we're finding a lot of these things intermediate. In size and you'll notice you, start running out of the rocky planets once you get to about 10 Earth radii they all start getting big okay, and for, the big fluffy planets you start losing these big large radii, planets, right around to Earth radii these, things could be considered gas dwarfs, there are things not that much bigger than Earth that are dominated by gas. But. You may also get things about 10 times the mass of the earth that are mostly rock okay. So, this intermediate, region is very interesting, we're seeing a huge variety of the, densities, of these planets and that's going to translate into a huge variety in their. Compositions, this. Is the w first mission, this is this is a, project. Being. Formulated now there's there's work, on developing. A chronograph for this instrument here the, chronograph was the instrument, for blotting, out the lights of stars this is a very interesting mission, concept, that the so. Called the twenty, Twenty twenty, ten, to astronomical, decade-old Survey came up with the astronomical community comes together about every decade and. Comes. Up with recommendations on missions and this is a very interesting case because it can study extrasolar. Planets, dark energy and dark matter so, it satisfies the people that study galaxies, and cosmology and, it studies the people that study, planets and it's actually, formulated, to work on planets in two different regimes it's gonna have a coronagraph for blotting out the light of nearby stars and it's, also going to image the going near the galactic center and look at many thousands, and thousands of stars to look for micro lensing candidates, the little in, case of star where the planet passes in front it'll, see an enhancement brightness, so, what that project, is gonna do this is this is showing the orbital, separation, semi-major axis, and astronomical units so the earth is one here's, the earth, and.
This. Is the planet mass and earth masses, now Kepler, Kepler, in this shaded region these, are thus these are the planets that pass in front of the star so you were very sensitive to the planets that are very close to the star but, you tend not to find the ones that are further away just cuz geometrically, they're, it's it's much more rare to see the distant. Planets lineup so, w first is going to help us sample the outer region, this is the realm of the Jupiter Saturn Uranus and Neptune type planets and even. Things down to earth size and smaller so we're gonna get a statistical. Survey. Of this, region. This sort of one to ten astronomical, unit region. Using. W first. This. Is an interesting plot and I apologize. Because I, this. Is going to get a little messy but this, is showing the distribution of masses, of objects. We've. Got stars, over here and this is their density how many per, cubic. Parsec, parsecs, are astronomers. Ruler, it's about three and a quarter light-years so, it's basically a number of stars per density, okay, so. This is. One. Solar mass there's, the Sun and this. Is not fitting all the data we have but the the distribution, of stars it increases. As you get the lower masses, and it decreases and recently. We've been finding things floating, around in space they're very low mass this. Is ten to the minus three Sun, masses, that is roughly a Jupiter okay, so, things, the size of our Sun are here things the size of Jupiter are here okay. So here's the Stars oK we've been studying stars for a long time, this, is the mass function of the stars it. Peaks around a couple tenths of the solar mass we have tons of these little dim red dwarfs in the solar neighborhood the. The mechanism for forming stars for collapsing, gas in interstellar medium seems, to prefer forming, red dwarfs our Sun, is actually kind of a massive star it's at one solar mass and you tend not to see things bigger than about 150, times and ask the Sun there's a very very massive short-lived. Stars as. You go below about a tenth of the solar mass you get so-called brown dwarfs okay. There's, a limit below which the, hydrogen in the core can't. Fuse the temperatures are too low and these things aren't really stars they're kind of the failed stars okay, so the last 20 years we've been finding more and more of these failed stars but, there's been a surprise okay, so this is from about a tenth of the solar mass down to about a hundred two the solar mass this is about ten Jupiter's. Recently. We've, been starting to see very, very low mass things in the field and now we're starting to put some estimates on their density other way the sorry there's the hydrogen burning limit, now.
When I squint, this is a paper just came up by Jonathan gagney I'm co-author on if I squint and I look at this you. Could just about fit a line through here I wouldn't. Place any bets on it the. Line I've picked is actually, the, mass function, for planets orbiting. Stars, okay, it goes roughly is the mass to the minus one power you. Have many fewer massive, planets than you do low-mass, planets if. You fit that function through here. These. Could be planets, that are floating, in space that are not orbiting, a star these could be the so-called rogue planets, and I, think I'm starting, to see data from a few different surveys now that I think there's that there's that there's a convincing case to be made that there's, a separate, population, these things fundamentally form. Different from stars the, physics, of gas, and dust on the scales of light-years, and. Gravity winning out over gas pressure magnetic, field pressure that forms stars and the, brown dwarf population, okay, but, below that there seems to be this whole different population, and these, could be planets. That have been stripped from, their. Stars and just roaming in space so, we keep talking about you know Alpha Centauri is, the nearest destination, in space. We. Could very well find things, that are on the order of the sizes of Jupiter's or Saturn's our Neptune's, floating. There. Could be many more targets, to spot stars between us and Alpha Centauri and. These would be dimly, glowing in the infrared so. There's our there's our rogue planet. The. James Webb Space Telescope is, gonna be launching in 2019. This is gonna be the successor to the Hubble Space Telescope, it's, gonna be studying. Planets, that pass in front of those stars some, of the missions like Kepler and tests, and k2 are feeding. Targets, into the, plans for j ust what, we want is nearby bright stars that have planets passing. In front of them and we can measure the spectra of those planets. And so there'll be some interesting extrasolar, planetary, science coming out of Jain ability but. Beyond JT gusty, what. We really want to see is is the small pale, dots the, pale blue dots next to stars and so, this is one of the concepts, that's being worked on in fact here at JPL is a so-called star shade okay the, idea of a star shade is you launch a telescope, and then. You launch a separate spacecraft, okay. And the model they have is about 34, meters in size pretty, big but. You can you can wrap it up inside, of a rocket and let it unfurl in space, and this, star shade you would put between what, star you wanted to look at and your telescope, and so, the star shade would essentially, form a little shadow and you have to keep your spacecraft in that and then. Look for the din little planets whose light is not passing through the star shade okay, lots.
Of Technical challenges but, there's there's a path ahead and and, there's. There's currently proposals. Now to. To. Construct, the star shade there's actually a demo and one of the buildings here at JPL. So. This is what it would look like this is an earlier concept, where the star shade would actually launch with a telescope, one. Of the proposals, on the table now that's. That's being considered is you've. Launched the W first spacecraft in the mid 2020s, and then a few years later we've launched a separate star-shaped. Mission and, the. Star shade would, move, about 80,000, kilometers away from the spacecraft right. Here they show like they're close together they won't be close together, and. The. Star sheet has its own fuel and so, it would sort of park in front, of the star, W. First would look at it or whatever future mission comes. Up and you, would study the planets. The. Faint, planets and basically, if you want to get down to things that are about the size of Earth this is really the next step you have to take right now well not this, is this is going to be a ways. Of head of the 2020s. I'll. Show. A few slides on Proxima, Centauri because, you've probably heard a bit about this in the media so Proxima Centauri's the nearest star to the Sun it's about 4 light years away and it, was a it was a great discovery middle, of last year and. This was a ground-based discovery. There. Was some astronomers in Europe that used a ground-based telescope. With a spectrograph, and they were measuring the motions of Proxima Centauri very closely what they decided to do was observe it night after night after night after night after night for months okay they took a lot of telescope, time to do this it, was worth it okay so, what they found on the velocity, signal of the star was this little 11-day, ripple, at the 1 meter per second level okay this is one meter per second actually not a lot of walk over there right here, one. Meter, per second this is an earth-sized planet, tugging on a little star, about a tenth of the size of our Sun, so. This is the art for Proxima Centauri B, this is Proxima, Centauri the. The little faint star it's, actually a triple system our nearest stellar neighbor is a triple ok our Sun is a little bit of an oddball as a single star lots, of stars come in doubles triples quadruples and up, so, the art here actually shows this there's there's two sun-like, stars very far away about 10,000 astronomical, units away from the star and then here's the little red dwarf star. Proxima. Centauri, so. These are the designations, Alpha Centauri a B and C and in the so called proper names Rigel, can Taurus this is this was the, foot of the Centaur Proxima. Centauri was the nickname for the dim, red dwarf discovered about a hundred years ago this. Is just showing a comparison to the size of those stars compared to the Sun Alpha Centauri a is a little bit bigger than the Sun Alpha Centauri B is a little bit smaller than the Sun Proxima, Centauri is about a tenth of the size of the Sun and there. Could be planets, around Alpha Centauri a and B -. There's. There was a, purported. Planet, a few years ago when Alpha Centauri be so far that seems to have, not. Been confirmed, but so far Proxima Centauri B. Looks good this. Is showing a comparison of the Sun and Mercury's, orbit okay, our innermost planet. Along. With on, this, side Proxima, Centauri dim, little red dwarf if you, can see it's it's luminosity is very tiny it's about. 0.001. Five times the. Energy that the Sun is putting out this, is the habitable, zone for Proxima Centauri and lo and behold Proxima. Centauri B it. Orbits its star at 11 days but this star is so dim that if you want to look for places as liquid water you have to move this close to the star okay. You're camping real close to the fire to, keep that water liquid now we don't know. This. This planet is probably a rocky planet based, on its mass we. Don't have an estimate of the radii we don't have an estimate of it we don't we haven't seen the atmosphere, anything yet so, right now there's a bit of speculation on that.
By. The way so eventually, these planets will need names eventually, your kids and your grandkids and beyond. These. These some of these objects are gonna be so interesting that they may have their own proper names you think of the planets, in our own solar system so, this is the first attempt, the the International, Astronomical Union did last year there was a contest opened up to the public called. The. Name EXO worlds contest, and so, there was a few dozen of these exoplanets, were actually named and you saw a few of those in the talk and so some of these are like there's, a very nice example here the Mew system, is known, as servantes, Quixote, Jolson a Arase Dante Sancho, so something has some interesting themes, based on characters from books. The contest was there, was entries from all over the world he had to be an astronomical, organization, to apply so that, there was classrooms, and strong, amateur, astronomy clubs that contributed and so. There was a lot of great entries. And so these are the ones that one out it was six hundred thousand, votes from all over the world for these so, this this. Was a this was a the first attempt of the IAU at this but but I suspect, we'll be doing more of this in the future I, just. Wanted to look back at Earth there's this great picture of the voyagers, took a Voyager. One took in 1991. This was the earth as. Seen from tens of astronomical units away from the the. Sun. Oops. Oh. It. Didn't show the other one okay I have another one there was a picture was just taken this week from Mars, from. One of the Mars orbiters, it shows the earth and the moon is seen from Mars, but. At, the end of the day we'd like to also understand the, the earth in the context, of the other planets we only have one earth we, can't run the experiment, of, forming. The earth and. We. Probably shouldn't be tweaking too much with the chemistry of the atmosphere in the oceans just a suggestion, I like, the earth the way it is. But. We get to see all the different examples of. How. Physics, and chemistry comes, together to form other planets so, this is sort of a it's January this is the state of the galaxy report, this, is I'm gonna give you a few examples of a few results these are basically extrapolating. From what we know now okay, we don't have a complete census of all these objects, this. Is just from what we've been able to gather from from some of these systems, first, off extra planets are ubiquitous okay, nearly every star you see in the night sky has planets, this is amazing okay this is one of the terms that was in the so called Drake Equation how common are planets we, now know planets are very very common. Sun-like. Planets, sorry, sun-like stars typically have five, or more planets there could be even more this is only down to the size of about half an earth okay, so most of those stars not only have planets they probably have several, planets. The. Super E