Rose Center Anniversary Isaac Asimov Debate: Is Earth Unique?

welcome everyone back to the American Museum of Natural History on this auspicious day 1010 2010 the day we've chosen to celebrate the 10th anniversary of the opening of the Rose Center for Earth and space some of you were here earlier with the festivities we had a huge cake we had live entertainment we had we gave out awards for the best video we had a video contest the best two-minute expression of what science has meant to you for the past 10 years and so if you go to the Rose Center website you can see the award winning videos the runner-up video I like to characterize as are you smarter than a two-year-old because in it there's a two-year-old reciting all kinds of cosmic phenomenon and names of things and it's a remarkable video it's gone almost viral on the net so check that out when you get home this is a special specially inserted Asimov panel debate normally we meet in the spring for this once a year how many of you are sort of regulars to the spring one excellent and who here is the first time you've ever been to an Asimov debate my gosh where were you we you been what what what welcome to this one we'll be doing this again at our usually scheduled time in the spring follow the news announcements for that for this occasion we thought we would involve a few more geologists and answer a fascinating question has been on our minds for a long time many people's minds is earth unique is earth unique now we don't mean exactly unique obviously any planet is unique down to its details so we're really asking are the general properties of Earth something we can expect to be common in the galaxy or rare and that question does not have an easy or well understood answer at this point hence we make it a subject of this debate and interestingly what happened just a few days ago in the news an earth-like planet a Goldilocks planet around star Gliese 581 it is well the star is Gliese 581 there are several objects already known to orbit that star the most recent of which is and slightly larger than earth sized planet orbiting at just the right distance which if it had water under an atmosphere it would remain liquid too close to your host star it evaporates too far it freezes so it's Goldilocks temperature just right and on earth where there's liquid water there's life so water is a tantalizing tag for us as we conduct our search for life in the universe that's the first of what we expect to be many such planets in orbit around their habitable zone we have a remarkable selection of panelists one of them in fact flew in from Europe another one came in from California landing just moments ago and I'll be introducing them in sequence I have first an astrophysicist well by the way all of the BIOS are in your schedule so I'm not going to read through all of them they'll be here for you to see and I want to get straight on to our panel discussion before I do let me publicly acknowledge the support of this program by the friends and family of Isaac Asimov who's a longtime friend of the American Museum of Natural History he used our libraries to publish his 600 plus books one of the most prolific people in the history of book writing and on science fiction science people wrote books on religion not not a single subject was beyond his reach and much of his research that he conducted was here at his backyard Museum the American Museum of Natural History so we're indebted to the support that the loved ones and Friends of Isaac Asimov have provided for these past 10 years and so first let me bring out on to the stage right now fred adams is a professor of physics at the university of michigan fred adams there you go they will each begin with a minute or so of what it is that they do and why and so we'll wait till we get all five panelists out to discuss that come on out don brownlee he's professor of astronomy university of washington in seattle don brownlee we have paul falkowski he's professor of geologic and marine science at rutgers university I just realized you're a pretty cheap date you just came across the river here from New Jersey I can't we'll have to invite you more often and where am I here who did I leave out yes thank you Chris McKay he's a NASA scientist working at Ames NASA Ames Research Center at Moffett Field California and we have mini roasting he's professor of geology University of Copenhagen Minich just a half-hour ago we had a conversation in a room in the back because we all took a look at each other so we're all guys you know so this did not go unnoticed by us and we're going to check to see if we've had some inherent bias over the years or what so we'll be checking on this in future Asimov debates yes just while we're in demographic statistics in the whole world of astrophysicist 36 of them are black and one of them host this so that's just in front you know so we're doing good on some cows here I think all right [Applause] uh so Fred why did I invite you to this panel but who are you to us today just tell me remind remind me I work in theoretical astrophysics I work primarily as a theorist so I do calculations more than observations I spend my time primarily in a physics department rather than an astronomy department but I work in both camps so I kind of bring that to the table I guess I spent most of my time working on star and planet formation about two-thirds of my papers are in that realm which is relevant to today's picture or today's some discussion and then I spend about the other third of my time working on larger scale things cosmology and related issues which kind of informs the big picture of what we're talking about so you think a lot about the physics of the universe and how that shapes what the universe ultimately looks like yes exactly and as most of you work on computer or is it just back pencil and pad the answer to that is yes I'm one of the old-school people that still do calculations on paper but as you know and most people though eventually you often have to put equations on computers as well so I go back and forth between the two media okay excellent thanks for that don brownlee your author of a book rare earth so you'd like the right guy to come in here but what else what else have you done lately so I'm an astronomer I work in a solar system planetary science I was also head the NASA Stardust mission that bought comet samples back to earth and along with I have to interrupt their I remember a movie what they did that like the Andromeda Strain where they brought particles from space i'm just-just you were not worried about this you would not believe it but you look at the look at the movie the capsule they brought back in that movie was almost identical in size and shape to the one we brought back with comet death I knew it and and the instruments were very scientific in that movie they use electron microscopes mass spectrometers were very similar to what we actually use on the comet embolism many years later although JPL and Caltech were with advisers on the dramatists train but yeah I'm also an author with Peter Ward paleontologist on two books one is called rare earth which is just says the earth is rare and is about the rare earth hypothesis the idea that life may be common in the universe but like on earth over its entire history it's mostly microbial and it takes very special conditions to have animals like us the second book was life and death of planet Earth was amazingly the first book about the long-term future of our planets every some things that everyone should have learned in third grade and didn't but future Earth history okay so we'll get back to you on that to find out if we actually believe you that earth is as rare as you suggest so Paul we get your name print out full Kowski I tried Bukowski yeah tell us where you what part of the universe you come from so my interest here is the evolution and origin of life are broadly writ but from a concrete point of view I study for many years the origin of biogeochemistry which is to all of us in this room we're breathing oxygen that was created by organisms it's not a trace gas on the planet so there's an oxygen cycle there's a carbon cycle there's a nitrogen cycle and I study how organisms basically transform the planet to make sure your bio geo chemist that's right you just stapled them all together okay and this sounds like that's an emergent field because not that long ago our scientific professions were pretty divided up department by department so are you Arendt agait or at least on the frontier of a trend line that we should look forward to yeah I'm trained in biophysics and molecular biology and I'm in a geology department so you could say it's a trend line that's a little weird so you're a one-man cross pollinating machine yeah I tried okay Chris McKay you flew in you said you just flew in from California but I don't think so because I think you just flew in from Mars you Mars is like your favorite planet and that's all you ever talk about well but for example you can have breakfast with the guy and you eat in water drinking water and eating you know say you know on Mars this would everything no matter what you say or do he references back to Mars and it's it's a good connection to earth and the question of life what I'm interested in is is there life on other worlds and is that life different from life on Earth and in a way it's asking the question is the story of the most important thing that we see on this planet what Paul studies light and the biogeochemical cycles that it creates is that story repeated on other worlds and if it is are the organisms that are doing the biogeochemical cycling on other worlds similar to the life-forms we have on earth or are they aliens I'm going with the aliens why cause I see an advantage for myself all right meaning rosing I have to tell everyone that you were born in Greenland that that is surely the first person I have ever met born in Greenland and how many people were in your hometown when you were born well there's not really a town of a seven people so it is a town upset about it's about a family can't even I can't even look City I guess think that we don't even know how to understand that a town of seven people well it seemed quite busy at times actually so what scares me a little is that you're born in Greenland and Greenland is the subject of your research specialty and and you've done great pioneering work there it makes me worried like had you been born in like the Bahamas or something you'd still be on the beach and we wouldn't have learned what we have about Greenland no I think actually have I been born in Bahamas I still go to Greenland because it's the most interest in place on this planet and it's a place where I do what what I invest that I am a geologist and I have to warn you that the geology is the only science where your feet are more important than your head so that's the vagal you used to work across the fields and be done right with the cameras and so that's kind of the level of sophistication I operated okay so let me let's start out with you let's start our conversation oh the way we so many new hands have been raised the way we're going to conduct this is we're not actually talking to you we're having a conversation like we're at a bar or something among ourselves and you're eavesdropping on it okay that's how these go you got that okay we're just chilling up here on the stage so so Minich you we're trying to understand whether or not Earth is unique but you work in Greenland and there's nothing more foreign that I can think of then Greenland especially since it's mostly ice so it's like badly named to begin with how could study in Greenland possibly inform the rest of this conversation about Earth well Greenland had preserved the oldest part of Earth so we had rocks in Greenland have experienced 3.8 billion years 3,800 million years of Earth history and that actually is at almost 1/3 of the existence of the entire universe is recorded in these rocks right so why are you Greenland rocks older than somebody else's rocks well because we found it there what what there's no logical explanation its death the way it happens to be no no no so is there some geological fact about Greenland that enabled it to keep older rocks compared with some other place on earth not really I think they the magic point about Greenland is that it has been glacially polished then the last few thousand years so that means that the rocks are not covered by soil and plants and other active things so you can really see the geology and that allows you to get a much deeper insight into how the geology of Greenland is put together and that allows you again to find the really interest in rocks so you're saying when you say glacially polished so a glacier works its way it's very heavy and deep and it just sort of carves its way over the surface and then if it retreats it's kind of a freshly exposed exactly yeah if you if you try to do that in Arizona someplace like that you see a lot of yellow sand and more yellow sand or more yellow sand and green then you have Christine rocks and they just sit in there for you so that's the the marvel of the place okay no I never knew that about it that very good and actually I could you switch places little Don yeah all right it's a good luck there you go thank you oh that's much better [Laughter] so Don what are your best arguments for whether or not earth is is unique is it are they philosophical or do you act you have real science behind these claims because I I read your books and you make some interesting points and when you say unique is it are we is it rare because of the life that's on it surely you agree that maybe other planets have oceans so where you coming from well the earth is undoubtedly rare I mean it's rare in the solar system it's totally different than any other place in the solar system look at this from astronomical standpoint well I have not to people wait the solar system is this big in a galaxy that's this big and you're asserting that it's rare think of the universe a whole you can do that the lot of people like to think of the universe is being a very friendly place it's almost an incredibly totally hostile place I agree if I only get a couple places where we could go and look to me earth-like means if I was there on this other body I feel at home and I could go and breathe this rich oxygen atmosphere and be happy and look out and see palm trees and beaches and people dozen beaches or something running up down the beaches and you know our neighbors it's always just a more vastly vastly different than we are I remember being Mars and Venus our adjacent planets the whole rest of the works you know I I never went when the when the Huygens probe landed on Titan both a big moon around Saturn all the comments was why this really earth-like because it has liquids land and it kind of low slimes it had that coastline it looked like Louisiana you know when you fly over Louisiana but it's only a little bit warmer than liquid nitrogen and you would not feel you would feel lost at home and Titan than you would in Mars which is a really unearthly like like plate so there are lots of places we need to be careful Chris he he's gonna fight you so bad about Mars I mean so anyway the earth is rare to other places in the solar system and the earth we live on now and think of our earth is actually not typical for the earth throughout its entire history earth will last about ten billion years and yet it took four billion years of geological and biological evolution our planet to get animals on so you know what is earth-like typically in the past you've landed on earth you'd look around hey nothing here let's zip off to Alpha Centauri or something even though it was life on Earth for most of its life time it was microbially it wasn't animal life and the earth will spend at least half of its entire lifetime as an ocean free planet and most Earthlings right now you look at that plan and say god that's not that's that's that's not an earthly planet there's no ocean can't be like her well it is Earth Earth has changed a lot you're saying earth isn't even like Earth for most of Earth history I mean earth most likely when it was very young was a water world completely covered with water I mean you know we don't know what it takes to support life but we know it takes to support us and we can't live anywhere else the solecism we can't live on earth as we are right now during most of Earth history I mean more than two point four billion years ago there was no oxygen in the atmosphere so we would fix c8 just ah yeah gone although the anaerobic microbes were doing just fine microbes are tough much tougher than we are but we're smarter so weak weak in the end we may beat the microbes believe it or not so we tell ourselves constantly that we're smart we live an artificially the paper every day I'd that's evident counter evidence too so Paul yeah one thing that I think is not widely appreciated by the public and perhaps even by other scientists is how many cycles are going on simultaneously on this very earth in which we live and for me what impressed me most I think was to realize that if you're going to look for another planet out there in the galaxy the urge is let's find a planet that has an nitrogen oxygen atmosphere as we enjoy here on earth and then that's where we'll pitch 10 and live as though that's the kind of atmosphere that you just might randomly find among planets but of course life infuses the atmosphere with these properties and life affects the oceans so that we're not just living on a planet we're a participant in the planet so these tell me about some of the cycles that either we contribute to or that affect us directly just just so life is made up of six major elements hydrogen carbon oxygen nitrogen sulphur and phosphorus and all of these cycle and the cycles to first order are driven on this planet by tectonics because the Earth's interior has uranium thorium and potassium and is radioactivity and that allows the mantle and to cycle and it brings for example through volcanoes co2 into the atmosphere that's why we have co2 so we need our volcanoes for this absolutely with as bad and menacing as they are they're fundamental part of the cycle absolutely first-order fundamental part of the cycle the carbon dioxide that's in the atmosphere absorbs water it makes carbonic acid which is like Seltzer Seltzer rains on igneous rocks like granite and the igneous rocks so cold weather so of magnesium and calcium are taken out of those rocks by this weak acid and you form chalk and so that's to first order the carbon cycle so chalk is a repository of the carbon exactly and so that cycle which is dependent upon the weathering of rocks and volcanism has maintained a carbon dioxide concentration that has not led to a runaway greenhouse like on Venus or has not collapsed totally like on Mars so the amazing thing about this planet is it's a Goldilocks situation where tectonics stopped on Mars and it lost its atmosphere in Venus it's incredibly incredibly warm there's huge amounts of co2 and it's much too hot for life to exist as we know it and earth is the only one that is within the so-called habitable zone where liquid water could exist where there is actually physically liquid water on the planet and there's nothing to do with us it has everything to do with just this volcanic activity and rock weather so that's so when you say a cycling of the land you're talking about continental drift where where the crust goes down gets reheated and basically comes out of a volcano someplace we're talking about sedimentary materials from the oceans primarily right it's this is marine sediments the marine crust oceanic crust going down underneath subducting in this case now underneath the cratons the continents and and coming back up in volcanic material gases in the mid-ocean ridges into some extent on land but the mid-ocean ridges primarily so that's one cycle and then there's a nitrogen cycle for the natural nitrogen cycle is dependent upon an oxygen cycle and the oxygen cycle now is dependent on life and all of these cycles are intertwined so it's not as if one cycle operates freely they all are related to each other like a network of wires in a circuit diagram and understanding the feedbacks here is is not easy and it's one of those things that we really don't understand very very well frankly in science because we don't have experimental planets where we could go out and say oh let's kill off all the nitrogen fixers and let's see what happens well we're already experimenting on earth that is our experimental planet last I checked works fermenting with ourselves so Don may say that you know well what what are we doing here I would argue that what we do was carry ecoli around from place to place and do it in different places so we are basically a vector for vessels for bacterial growth Rebecca yeah I want to look this one up we have more bacteria living and working in one centimeter of our lower colons than the total number of people who have ever been born that right so so in terms of who's in charge they would have a different answer to that question and then we would write out exactly yeah two point five kilograms approximately of each of us is bacterial well it's just a nasty thought [Laughter] right we got bacteria on our skin and in our digestive tract everywhere right you are not who you think you are [Laughter] creeping me out Chris mr. Mars did you really just fly in from Mars no no I just came from JFK from JFK okay just have to clarify that let the record show so where how does Mars fit into this you know we've all seen perhaps images of Mars and they're tantalizing you see river dried riverbeds and river deltas and flood plains and the order clearly had a significant presence there and we like water we think of life when we think of water the place is bone-dry now something bad happened on Mars so so do you apart from your interest in finding life there maybe subterraneous Lee is there some lesson that you can learn from Mars that will apply here to earth because I think we want to keep our water yeah the general lesson of take care of your planet is a good lesson and we we might learn that lesson by studying Earth obviously but also including Mars in that study but the more important question I think we're asking about Mars is the fundamental question about life as everyone here has been talking about life is all over on this planet it's done amazing things it's continuing do amazing things we eat it for breakfast lunch and dinner it's an important part of everything we think about when we think about earth but we don't understand whether that phenomenon is unique to earth or has occurred many times in many different places Mars is our first chance to really test that to really go and look this planet had water had water for a long time it was kinda like earth did it have life and if the answer to that is yes it had light even if they're all dead and that life turns out to be different than Earth life what I call a second Genesis that's really cool different as in no overlapping DNA or whether it has DNA at all well different if it has a separate origin even if it's got DNA if we can deduce that it represents an independent origin of life so that right here in our own little solar system life started twice that's telling us some amazing things about the nature of the universe so that would say that life that Mars that earth in fact would not be unique that if our one of our closest neighbors had these properties at some time in its past exam then we're good to go water a little bit atmosphere yeah that means the universe is full of life and that we have every expectation that we find other worlds around other stars with water even if they don't have all the plate tectonics and things that keep them active for a long time they still have a chance at life life becomes that a natural feature of the universe not a quirk of some odd little planet around this curious little star I like that okay Fred you you think about the formation of solar systems and employment and of course you you were never there so you have to sort of apply the known laws of physics look at examples in our galaxy where planets are forming what have you concluded about planet forming in general but our solar system in particular well there's a number of things you can say one of the first things that we found circa 1984 is that when every star forms it forms of the circumstellar disk around it this was something that caught and Laplace had predicted 200 years ago but no one had actually seen until the 80s circumstellar disk you mean you make the star in the middle of there's extra stuff that forms a platter there's actually a gas and dust surrounding it in orbit around it and the remarkable thing about these discs that we found in the 80s was that they have the right mass in the right size to form solar systems before these discs were discovered people had done the exercise of taking the planets in our solar system and augmenting them with extra mass extra gas to make them have solar composition so that they would have the same composition as the Sun and then they would deduce the properties of the the nebula that our planets formed out of these discs have a range of properties but pretty much exactly what we would predict so the birthplace of planets were predicted and seen and measured in the 80s which argues that things are right conditions are right for planets to form then in the 90s we found planets around other stars right now there's anywhere from 400 to 800 planets depending on how you do your accounting that we've discovered orbiting other stars and the number changes every day since I have checked the internet for a couple hours there's probably more in fact at 10 o'clock tonight they will be more preprints on the Astro pH preprint server and probably an announcement of another planet so their planets everywhere right there is an exoplanet app for the iPhone oh there is that app yes yes and so it has all the properties of all the exoplanets and every time you update it it gives you the latest file on it and it shows you the orbit and it's pretty just just look it up and keeps you at 7 o'clock in the morning do what you say it beeps to at 7 o'clock in the morning tell you there's a new planet Hey yeah I don't mind that cool with that but anyway if you take the observed sample of extrasolar planets and you have to do a bit of an extrapolation because we haven't looked at every solar system for as long as we would have liked but you can deduce what fraction of those solar systems have planets and that projection gives you anywhere from 20% to 50% what that means is that anywhere for 20% to 50% of the stars out in our galaxy or at least in our solar neighborhood have planetary systems of some kind so that bodes well for looking for earth this is like the Drake Equation where you look at the probability of a star that has planets that has a planet in the zone yeah this is exactly one part of the Drake Equation for those of you who don't know the Drake Equation ask the question how many intelligent civilizations are there in a galaxy and in order to get up to an intelligence civilization you have to have a number of factors you have stars you have two appliance you have to have the planet have life of some kind you have to have animal life as we've seen then the animal life has to somehow become intelligent which may or may not have happened here but then it also has to have technology in the Drake Equation so we're a long way from being able to predict the last of those factors but one of the things that's I think very satisfying is that the astronomical part of the Drake Equation is rapidly becoming coming into focus yes sir solve problem at that level and it's being solved in the positive direction yes there are solar systems yes there are planets yes there are places where life could in principle arise I would go further than that if I may because let me get back to you Paul you gave a list of both of the two of you sitting together here each would let leave us to believe that what we see here on earth because of all this this interplay of cycles and conditions and circumstance it says though a has to go to B to C to D and we're like Z in this sequence and if you break any of these chains something bad happens and we don't show up or something catastrophic happens to the planet but let me ask you practically every time we have imagined that something was a special condition upon further exploration in the universe it hasn't been so for example even in the Drake Equation where they talk about the habitable zone before we call it the we would only later call it the Goldilocks zone the habitable zone we have one of the moons of Jupiter Europa kept warm not from the Sun but from the gravitational stressing of Jupiter and the surrounding moons themselves so in fact there's another way to do it as well if you have a planet as big as the earth that lives in the outer solar system where the moons of Jupiter lived the natural radioactivity will keep liquid water pockets they won't be on the surface they'll be beneath ice sheets so you will so the undersea vents that's a source of energy nothing to do with the Sun life could just be doing the backstroke down there and won't even care what's happening on the surface yeah well what we know for sure or what we think we know is that there will be liquid water and there will be an energy source the rest is what we're debating here so what I worry about is could there be other combinations of cycles that would still work for some kind of life that we might not have dreamt up yet well and if that's the case yeah you could say earth is unique for us but unique for any kind of life at all maybe not because you haven't thought of these other ways that because nature can be inventive at times and it's typically more inventive than we ever are so how do you address a criticism that you just haven't thought of other ways to sustain a planet that could to create a planet that could sustain life so the way biologists have looked at it over the last 20 or 30 years is they've looked at what's called redox couples that means the difference in energy between for example hydrogen and oxygen and that redox couple is very large and obviously everybody in the room let's do the following experiment just take a breath okay so you just exchanged hydrogen from your body with the oxygen in the atmosphere and the primary gas which resulted from that was water okay so that's a very very high energy gap which allows us to derive a huge amount of energy from that reaction that reaction is a relatively recent reaction it only happened about 2.3 or so billion years ago before that the reaction was constrained to hydrogen sulfide or iron oxidation so those reactions have much much lower free energy and you can doesn't matter what planet you're on you're endowed with a certain number of redox couples so on Europa the only reason you could have life in the interior Europa is either because some some something is supplying a redox couple from the interior of that moon or there's a subduction of ice from the surface into the interior and it cannot be a closed system and all systems ultimately have to be open systems so what I'm saying is in our case we only make bond energy new bond energy on this planet to first order because the sun is shining and something is taking water and splitting it which we don't do splitting the water and creating energy gap and using that hydrogen effectively to reduce the co2 in the atmosphere to sugars that we eat so those are really common metabolisms so in fact correct me if I'm wrong the main engine of on the space shuttle the big orange engine is a hydrogen oxygen reaction and so it's just making water as it's exhaust and it's exothermic and the thing takes off right you and I are fuel cells with just a much more controlled rocket I think you could also if you're also add that if you go towards the intelligent life you'd say that our brain uses a quarter of the energy that our inside body connects us and that means that you need a very intensive source of energy if you want to be intelligent so if you should sustain yourself at the thermal energy inside a Moon someplace there's no chance that you could organize higher organisms on that people amount of energy you have there to that level I think I think they'd be so dependent on it and being able to convert the energy from the Sun into something that we can use to to sustain a high level of activity that they're so there's still more intelligence in Louisiana than on Titan we can be sure that the trick together he can pull off that joke here in New York Vienna just try that in Louisiana I think I think they just passed a law that you have to carry a gun so you have a different reaction today what do you have to say about what they just said well I have a more optimistic view and that that's why I came to you yeah I think we should look for strange things and hope to be surprised and the strangest world that I is promising is tightened because there there's a liquid and on earth we know that life is tied to liquid water we don't know if the critical thing is the liquid or the water and on Titan there's a liquid it's the only world of the solar system with a liquid on its surface besides the earth the liquids not water it's liquid methane but in many ways liquid methane is a is an icer liquid for life than water waters aggressive at tears molecules apart it's at high temperature there's a lot of drawbacks to living in water but methane is the gas that comes out of my stove yeah but on tight I ignite and cook my food with that's because we have a world that's hot with oxygen on a suitable world a world that's really built for life the temperature is very cold so people so things can move very slowly and methane is a liquid it'll look just like this clear and if this was Titan it would be stable it would be a liquid and you could imagine a biochemistry spaced on that liquid finding that would be very very interesting this is way outside of any box that they've been talking about right actually it's out not just outside the box it's on the other side of the street and that's what makes it so interesting if we can find life that's that strange then we know the universe is really full of interesting creatures I I had an incident yeah I was interviewed on Charlie Rose this is now 15 years ago when the Mars Rock story hit remember that the Allen hills Mars Robert uh US meteorite on earth discovered to have come from Mars all by itself it was studied for for the chemistry in the nooks and crannies and there was some curious up there was some curious properties of the material that was in there that was suggested that maybe it was life then they showed the picture that was a little wormy looking thing and that was not ever advanced as evidence for life but it was just a curious photo in that interview there's a biologist piped in and he sees the picture said that can't possibly be life I said why not and he said that's only one-tenth the size of the smallest life on Earth and I'm still waiting for him to give the reason why that can't be life but that was his reason and then I said last I checked this is from Mars so why is earth your measure of this and so I wonder whether biologists are sort of harping back to to his point I wonder if I once you're kind of stuck in there in their sample of one and the sample of one is all life on Earth has common DNA you don't have another exam now that's not this story what's the story the story is that you have to if you're going to have life you have to have two properties you have to have self-replication you have to have a metabolism how do you know this well otherwise how do you define that's what that's not an answer to what's the definition of life you give me that comment and you say well otherwise how would you do it I guess what would you you went to Titan and you found what would you look for if it's if it's not replicating and it has no metabolism what is it okay so now you if you define it that way and then you find something else that's not that well how do you what do you do with it it's called a mineral but you can call the mineral okay it's a Rock Gym okay so we have words for things that don't do that already is what you're saying right yeah I mean I can plug my computer into a wall and it has a metabolism of a sort uh-huh there's an energy supply to it yes it doesn't replicate yet so stars stars have a metabolism and they're self-replicating there's a star alive no they don't have a metabolism in a sense yes they do eleven energy supply that's an energy supply they but they're not they're not Darwinian they don't reproduce mutate and then are selected by an environment that's a very earth barrel it's statement well I think it's a more general statement and that's what we'd be looking for on Titan we wouldn't be just looking for a reaction because there's reactions there that aren't biological and we wouldn't just be looking for replication in the sense that a fire replicates or a cloud replicates or star replicates we'd be looking for that unique biological process which we call Darwinian evolution which involves replication with mutation and then selection from an environment and that cycle what is created the complexity and diversity of life on earth that cycle I think could operate on Titan so Paul's right in the sense that there is some fundamental properties that we can ascribe to life and we can look for them in other settings now this bit about how much energy our brain uses that's fascinating I think most people don't carry that knowledge with them but that's why they always say you lose a lot of energy through your head and you wear a hat disorder it's related it's a related phenomenon now my afro kept my head warm completely I've never worn a hat and my head has never felt cold ever so that might mean they give me a hat it's like putting a hat on top of a hat I just just just it's just a just a comment so so but clearly Paul and Don you'll be happy if you found any life at all so we don't need to put the requirement of intelligence as high on this search for life there is no intelligence is very low on the search very low on this earth okay I mean to my mind if you take a look at life on Earth it really is conducted by about 1,500 genes that's it the rest is you know the color of the car the size of the windows it's trivia it's you know we we worship organisms in Darwinian evolution but in reality all you are is like a patek philippe watch you were just carrying genes to give it on to the next generation ultimately every microbe we are what kind of what you basically hold you're a vessel of genes as an organism of humans we're just going to hand off those genes like a baton to some other organism in the future that's what every microbe is there a vessel of genes and only about 1500 of them are really really really important so and they're the ones that make all the life on this planet really go you know in effect that's not a joke but it's really true that you and I are nothing but e coli that are organized with brains and eyes and with a mouth and that's it we're just this so we recall I brought to consciousness yes speak for yourself I don what was going on in the earliest time of Earth because last I checked the numbers life showed up pretty quickly on earth you know if you subtract away sort of the years where earth is still accreting from its birth sac the surface would be hostile to complex chemistry so subtract those years out because that's not fair to start the clock wait for that to be done start the clock how long did life take well in in Earth history you can see the earlier service history by looking at the moon he believed with the naked eye those huge craters the biggest crater on the moon is the backside it's called a salvation basis almost 2500 kilometers across the earth got completely creamed in its first half billion years of history it the heavy bombardment period actually ended about 3.9 billion years ago and that period is called the heavy bombardment period just one make legs Aradia thing any organism delivery would have call it holy all right right but anyway so there was a period of time which is envisioned by astrobiologists you know life may have formed again and again and again but every great big impact that came sterilized the planet but when that was over when the impact record ended on our neighboring moon which records its ancient history right after that there's chemical in an isotopic evidence that there was life on Earth so that suggests that getting microbial life may be easy really easy it was well who knows well I got what this is the challenge of astrobiology how do we try to outsmart organisms we know nothing about because we only know here's where our only data but it took no but it's it's not as if that we have no idea if life formed almost as quickly as it possibly could have you're allowed to say that at least nature found it easy to make life aren't you allowed to say that I think we have one important piece of evidence it is that we have no till dr. Greg go to any part of Earth history where there was no light that means that there is not like we had a period where there's no life and then life came and so all true the record we have we have presence of life and I actually tend to disagree a little bit with you about the 3.9 billion years ago because 3.8 billion years ago light was already the end very significant imprints on the planet and that would mean that that was not a very early type of life so probably life 3.8 billion years ago was already pretty sophisticated in the sense that but but I'll retract my criminal record but then no records of that prehistory but it must have had a prehistory to reach a little bit could really impact the planet or religion what you're saying it wouldn't have just been a tide tool over here yeah given what you see in the geologic signature it would have you would have complex communities of microbes you would have very efficient light that knew how to already by 3.8 billion years ago so this happens quickly so if that's the case and let's let's accept the likelihood that nature does not have trouble making life let's just accept that for the moment because I don't think that's a stretch to make that you like that we don't know I don't think it's us out and we did as soon as it could have we have 50,000 meteorites that were much more carbon rich but for nitrogen rich much more water rich than our planet they were warm and wet for a couple million years early in history solar system no life so it can't be totally trivial I mean these are from asteroids well so you're comparing whether life formed on a planet versus an asteroid yeah well what all the ingredients were there if you are living inside that asteroid you wouldn't know you weren't living in that's true you wouldn't know whether you're surrounded by water there's no sky to see you know it's like living in this room or something but but so there are environments Khai what specific just won't judge there's no life on the moon other than the astronauts that we sent there so we do know a lot about the solar system and we know that there's no life in the meteorites or some people think there is but most people don't there's no life on the moon the great thing about the solar system is that unlike everything else in the universe it's closed so we can in the coming years go to every single place in the solar system and look for evidence of life and even if we don't know how to define life my guess is once we see life on Titan or you Oprah or whatever we will then agree yes this is life you know it when you see it do your soul systems that you create on the back of an envelope and occasionally with the computer do they do they resemble what do they look like can you can you crank out the Earth's in your models what can what knob do you have to turn so that either you make a lot of Earth's or very few the surface density of solids that's the one knob that you need to turn to get planet's surface I don't know what that makes density of solids perhaps I should define it if you make that star and you have a disk around it there's about two percent in the case of the Sun two percent of that material is in the form of things that are not hydrogen helium things that are not gas we an astronomy called that heavy metals but heavy metals includes mostly carbon and lithium not what you think of as heavy metals they were heavy metals in astronomy before it was a genre of rock music okay yes to clarify not Bon Jovi right so the density of those solids is a single most important variable that determines whether you can make planets whether you can make them quickly whether you can make them in but in abundance in these theoretical calculations so if you have a metal rich system which means that you have relatively more metals these heavy metals and we do in the Sun then it's actually quite easy to form planets if you have a heavier disk so even though you don't have relatively higher abundance of metals but you have more gas in total or more mass rather in total then it's easier to form planets so as long as you have that one variable high enough then everything's ago these would be solar systems made later in the history of the galaxy where you have much more of this enrichment to make your high surface density of solids yes well those are the ones that are well because every generation of supernovae are cranking out heavy element lunches them into the cloud yeah but we don't want to be lost in vagueness here the supernovae that cause or create the heavy elements come from massive stars and massive stars live and die on millions of years timescale my point is that millions of years is actually short compared to billions of years so that you can have many generations of massive stars producing metals and still have a soul system that's quite old the extrasolar planets that we see now the ones are on these other stars those stars were targeted to be as much like the Sun as possible which includes the fact that those are also 4 billion years old these are not young stars that are just born right so even stars that old can have metals higher than those of the Sun so maybe I'll need you in the answer to this as well when I ask this could minsk if in these models if I have two identical earths in two different star systems they're basically identical because you can make them that way in a model and then you just step back and let events unfold is there is there a chaotic regime in what goes on so that in fact they could have divergent futures I think that if we say okay they both develop life at some point the history I think they will make they may start out being very very very identical but they will take a unique courses because today the the trajectory of the evolution of life is so determined on the invention that the life on Earth made basically the type of metabolic inventions that life made determined the way the planet functions today we tend to see planet as a substrate for life but actually life is a product at Birth is a product of the light basically the way we the wave looks you can make arguments that they are there the continents that we live on are here due to the metabolic activities of some type of microbes billions of years back in time and the composition of the atmosphere we assure is controlled by the by the organisms that live here the feedback of life feedback that's why feedback so and probably the stability of climate on earth is also coupled to the activity of life so the fact that that if you look to back back to the the geologic history it's actually very boring you go back and you look at rocks that are 4 billion years old almost and they look pretty much like any rock that's formed today in Hawaii I've always thought rocks were boring whether or not they were all but that's just me sorry oh it is true actually I'm sorry I I will I will reveal this little secret rocks are really boring and the earth is an extremely boring planet where that happens and even that would happen had it not been for life life is only activity that really important on the planet and that's what process all the energy that drives the geochemical cycles today that is life and not earth itself uh what happens to earth when all our volcano stop we did do we look like Mars eventually we will eventually if we had no more co2 coming out of the volcanoes life and chemical precipitation when removed the co2 the earth would lose its greenhouse effect and it would be instead of plus 15 degrees centigrade average temperature would be minus 15 degrees we'd freeze Earth's completely just like Mars in a sense this is what happens on Mars happened on Mars after several hundred million years it lost its recycling ability its outgassing a co2 lost its atmosphere and became cold and dry earth could go that way if volcanoes were stopped so don why is earth still warm and Mars and Mars isn't I won't say Goldilocks but no no I mean just wise as a physical body why is it still warm because Mars is cooled down right there's no we we source inside of Mars would be born closer to the Sun we have a much much more hundred times more geologically active no no that's my question have plate tectonics which is unique to our planet that's my question the plate tectonics is one of the big factors in keeping Earth hable one of this one of this one no wait wait I'm trying to understand Mars is dead and it has no plate tectonics earth has this energy source that has nothing to do with the Sun that's driving plate tectonics why do we why is that still happening on earth and it has stopped happening on Mars that's what I'm asking the earth and earth is Mars as much the order plate that comedy yes Matt yeah such as man well come back over here but it's not answers mass earth is ten times bigger than Mars in mass go in mass ten times more mass it's the difference between me and my cat and mass my cat that I can't do the cat can climb up a wall math a factor of 10 and mass changes the physical properties earth being ten times more massive than Mars has a much more active internal heat flow and internal cycling so the difference between Earth and Mars I think is not so much that Mars is further from the Sun yeah it's mass if earth was where Mars is it would still be a nice place to live well then how come Venus looks so different when it has the same mass as Earth well there you're right it's too close to the sound sorry no but III think that it's not all mass size matters I learned that on TV but but III also distance to the Sun matters too but I so so it matters distance to the Sun matters between Venus and Earth but not between Earth and Mars so you think you can sustain an earth as Earth at the distance tomorrow right right yep if Earth if Mars were the size of the earth we would be having this meeting on Mars instead of on earth look like this and if Venus we're at the distance of the earth it would probably be a nice place to that's right you got it now but I but I think I'd write this internal energy source must be very very some you know the details must be very very sensitive because the amount of energy you get from this internal radioactivity is ten thousand times less than the energy you get from the Sun absolutely and why it doesn't drive the chemical reaction right so I are in ten thousand make some huge data right there's a very important distant at different alter that is that we have the ocean that keeps hydrating the ocean floor that goes back into the into the earth and is basically lubricates the machinery in there so without the reflux of water into the interior of Earth you are also stepping up the earth is soft inside it's not a multi anything but it's soft due to the present water that's being subducted with the ocean floor so you're saying earth has it like a it's like oil in a car engine yeah something like that and like Venus has lost its water net but cannot duplicate a mantle and therefore the mantle works in different ways and then it does it doesn't work in this steady smooth operation as Earth does and you can also again argue that the stability of the climate is the the oceans which is maintained largely by life so you could say that the plate tectonics has been sustained on earth for four billion years or more properly portal due to the management of life to some extent or maybe to the full extent well Paul something interesting here I think can I disagree with minik for a second no sure what wait what about it are you disagreeing with well life is really important for this equilibria of redox reactions it takes some mixed gases because it moves electrons around but what you're saying is inside the physical organism we are highly out of equilibrium right exact okay but it's you would have a carbon cycle on this planet without without your light and we have three or four oceans of water in the mantle below the ocean then we physically see and that would be there without life also so I think we you know we over ascribed this Gaia ask world to this you know III just briefly Gaia s just telling Roma guy is Jim Lovelock and hypothesized this kind of feedback that life and the planet Co evolve so that the planet's surface conditions is always made possible for the future of life by life itself there's a feature of life that makes life more conducive for life the life is a stabilizing factor in the dynamics of the blunt as our mutual friend Jill Kirsch make it Caltech would say well if that was true then we wouldn't have had had snowball earth snowball earth were there period in time starting at around 2.2 billion years ago shortly after we oxidize the atmosphere where all the oceans appear to a frozen and they froze for maybe about a hundred 150 million years we still have refugia somehow for for life but certainly we stopped basically the hydrological cycle this planet became the surface planet became very cold and this happened apparently four times up until we got the Cambrian explosion but that notion got a lot of play it did it did yes more than perhaps it deserved I'm not sure I think it's a very interesting thing of how can you get a planet so far out of its its thermal zone comfort zone so that it never comes back it never comes back oh it doesn't never compact in this act it came back because of tectonics it came back because of all kanai's Imran persisting driven by tectonics so as long as volcanoes are a good thing no knock the knock to snowball earth eventually okay so what day will we lose our volcanoes no got several billion years worth of radioactivity left in the interior and we also have the liquid core that's producing a lot of heat when its serve and it's solidifying so we have we have to heat indirectly not only the radioactivity but girls have the liquid core which is releasing energy as it chrysten we still have heat left over from our formation that's in the rickety or atom okay so we have heat from our formation you got heat from all this movement I guess is friction down there you had heat from radioactivity and you just said a moment ago which I hadn't heard this number that it's what percent of the total sort of energy budget of the earth when you add in sunlight well it's ten to the fourth one and not one in 10,000 but that's misleading because most of that sunlight comes and hits the earth and leaves whereas this geothermal heat is coming from deep below the surface of the earth and it's driving the volcanoes and the tectonic it's actually getting busy it's doing something that that sunlight isn't doing so well in fact it has to do something in order to get out right that's what it is he trying to get out you know yeah because it was it has to crisp my fried broccoli in the Mojave Desert at night it's got four tires touching the ground and yet it's it's it's radiatively more related to space than it is to the ground it's not getting heat through the tires try to keep it warm okay it's it's getting heat from the Sun during the day and it's radiating it back at night when and that's what most the planetary surface is doing surface right but the subsurface is what drives the volcanoes and that such but the surface is where the light where the light energy is transforming molecules to make chemical bonds of life and one more thing you know to me discussing the origins of life is being simple or not is like saying you can talk about the theory of jazz and one day somebody like Thelonious Monk comes along and plays something okay so nature real I don't make pedal I didn't make that I don't know the nature nature somewhere along the line a felonious monk it wasn't just a theoretician of learning jazz theory it learned to play the piano and it took molecules and a made stuff and it made stuff that replicated and it made bugs and we can't do that we haven't been able to do that yet so even the very simple redox reactions like water splitting we don't know how to do we don't know how to make nitrogen into ammonia at room temperature but why should what we know how to do be any measure of what was possible in the early universe we know the structures of those molecules at very high resolution and when you know we talked about Astrophysical space that is phenomenal in terms of what a telescope can see well conversely or obviously we have incredible resolution of molecules and we can go down to 1.1 1.2 angstroms and see how these molecules are structured and yet we can't replicate them if I were to change the world for our energy budget I would invent a catalyst that splits water and if I could split water I get hydrogen the world changes instantly instantly so we have then an infinite source of energy for the rest of human civilization well so this brings up an interesting point a pretty important chemical reaction in the early Earth is photosynthesis absolutely okay it's a its nature figuring out a way to exploit the energy from the Sun to make you a bond because why not it's available to you that reaction is interesting I remember learning about it in biology but it wasn't so complex that I couldn't imagine it happening naturally would that be something that you think might be inevitable on any planetary surface you know it's still a Darwinian eyeball it's one of those things that occurs on earth and yet we really don't understand how this thing came to be so it occurs I think every biologists the studies the reaction believes in the evolution of this through some natural selection process but we still don't know the very early blocks that allow the electrons to be moved because of photons why not well I got I got Fred Adams over here claiming he knows how planets were born you can't figure out a molecule for early the trick of photosynthesis is the back reaction so if I take an electron off of a metal like manganese which is where the original electron comes from before it oxidizes the water and I put it the electron somewhere in most cases it just goes back down and nothing happens so the magic of the photosynthetic reaction is you move the electron and then we put it someplace where we stored it so it doesn't go backwards and that's been very very very hard to do for humans to mimic that we almost can do it in the next twenty years we probably will be able to do that pretty well but it's it's been one of those maybe biology is just it's kind of in its infancy I know it's hard to admit that as a biologist but not at all okay so maybe it's in its infancy and you need another century of this effort before you can show that something that today is viewed as complex in 100 years would be viewed as simple we we've been through this in physics exactly we looked up at the night sky planets we're going through retrograde nobody understood it Newton comes along and writes down the equation of gravity it is trivial you can do it on your iPod today well exactly the analogy is exactly right the beginning of the last century was the beginning of quantum mechanics and the understanding of physical properties and the physicists ruled the 20th century in science I think this is the century of biology and it biologists won't rule in the sense but they'll understand the rules of biology which has been a very very difficult thing to do so all right so well physics isn't quite done yet in the sense of don't things to do no but I actually wanted to make an analogy not a joke um one of the things I make just quick this is that wormy thing that was on the Mars Rock Allen hills 84001 and we don't know if it's really a worm there's just intriguing the photo was published alongside the research paper that described it so I don't know it was a quick these are just random wall paper about life on Earth and elsewhere so I in a row it's going to make the point that just because we can't reproduce something in the lab doesn't mean that nature can't do it readily a good example or easily yeah a good example of that is something called fusion every star in the universe runs on nuclear fusion in our physics labs who have been remar probably found it remarkably difficult to produce a sustained inept yeah that's a good word in doubt we produce a sustained control keyword controlled fusion reaction it's really easy to build a bomb that is a uncontrolled fusion reaction but it turns out to be really really hard to have a controlled fusion reaction but that doesn't mean that nature has any trouble with it nature does it billions and billions of times in billions and millions of galaxies so so let me ask in the planets that we're now adding to our inventory of the exoplanets we have a CO who here can tell us about the Kepler mission who's the best among you to just brief us on that I can go ahead just tip - the Kepler mission well just to lay the groundwork before the Kepler Kepler mission using ground-based astronomy we now have a database of approximately 400 hundred 50 planets discovered one at a time by telescopes the Kepler mission is a satellite that's measuring the presence of planets in a different way there's at least well there's four different ways to measure planets but the two that have found the most fruit are what's called the radial velocity method where you watch the star wobble back and forth in the sky and then you do in reaction to the gravity of the reaction to the gravity of the planet and from that signature you can deduce the properties of the planetary orbit the mass of the planet and so on on the other way to see planets is if you have a star and a planet goes in front of it then the planet will cast a shadow on the star and the star will appear dimmer for a little bit and then the planet will pass past the star and the brightness of the star will shoot back up that's called a transit so the Kepler satellite measures transits and it published a paper in June where it gave partial discovery to or claimed partial discovery to four hundred planets now the full story is that there are eight hundred planet candidates and of those they decided that four hundred of them were interesting and they didn't want to release to the public so they're keeping them in their drawers as in their desk drawers so that we can't see them yet and then 400 of them that they deem less than interesting they published as in these are the planets these are their stars these are their properties but what's confusing about that is that they haven't figured out their false alarm rate correctly so they thrown out everything they know is a false alarm but they still figure that of the planet candidates they have about 1/4 of them are actually not really planets so we have another 400 planets discovered as of June although only 300 of them are real and looks a little bit frustrating is that we're not sure which 300 about the real one I put the takeaway here is that this way is that there will be hundreds of planets it's a mission tune for finding earth-like planets yes and we're finding many smaller planets in this sample of 400 potential planets than we have in the sample of radial velocity planet because that one required the more massive planets yeah is it so are because they wiggle their stars more right so we're going to we're going to go to questions from the floor we have two microphones set up we're going to just a couple of minutes but just think about your question and feel free to come up what I want I just want to go down the line here and I don't know that we resolved anything but let me just get your take yes or no so is Earth unique in whatever what in whatever what the word unique means to you is Earth unique I think it's unique yes you think it's unique what do you think of course you say yes okay Paul I go with the odds it's not unique I think not unique when you have 10 to the 11th stars in the Milky Way in our galaxy you have a 10 to the 24th or some number like that in the universe I think it's the odds of it being unique or incredibly low I mean you just do the numbers with the Drake Equation you just need the front end well let me ask you this is it is it not unique in the in a neighborhood of in our little zone where you have to really cross the galaxy to find one I would hope how unique is it well now you look is it what if we look if we're looking at a life how pregnant are you you know it's a how unique is it I think the question this this seminal question is is this the only planet in a universe for example a good shot of Earth here now it supports life and if I view life as something that is far from thermodynamic equilibrium that can self-replicate then it leaves a gas trace somewhere it should leave aghast rates and therefore long before there was oxygen on this planet that was probably methane and nitrous oxide that coexisted we could have seen in that universe at that time if we were sitting with a interferometer for example evidence of life on this planet even though humans we're not here the gaseous effluences of life thriving on its surface we look basically looking for reruns of Gilligan's Island from you know that's what that what search for intelligent life is doing looking for reruns of Gilligan's Island from some planets 20 30 50 parsecs away and you know I'm not sure that we'll ever find that but I certainly think it will find disequilibrium gases and once if you see methane and nitrous oxide on a planet six parsecs away game's over well Gilligan's Island was a TV show in disequilibrium right that's right let us hope that that's not our cultural emissary that is first discovered by a unique or not life is common in the universe so in that sense Earth is not you right you think life is common in the rise you didn't say that you just said life is common well I think night yes sir I have no I'm not from Roswell New Mexico I have no inside information is here he is not authorized through the books Fred what do you got well I would say that earth-like planets are common so to be more specific if you just asked the question about the planetary properties rocky bodies are easy to make we see lots of them already we're about to see one as small as Earth any day now literally in the in the external observations and it's only a matter of time before we find some in the habitable zone there might have been one discovered in the habitable zone a couple of weeks ago the one that you talked about in your introduction so the planetary properties the beds for forming life if that's what you consider an earth-like planet we're there already the next question is there life on them well I agree with the last two colleagues here that you know life is just a physical process physical these happen everywhere life is just complex chemistry and in some what would be remarkable if it were not at least life in some form common I mean everything else that we've seen in astronomy we found black holes that are have millions of solar masses well they're not unique just one in every galaxy we found neutron stars that are something like taking the whole mass of the Sun putting it into a kilometer size thing and spinning it a thousand times a second well there's millions of those right in every galaxy and there's billions of those galaxies so by the way this correct this creates a fundamental philosophical rift between the astrophysicist and the biologist because we get stumped practically weekly with cosmic phenomena that we never ordered and then we get millions and billions Oh from that point of air coming from that point of view I would have to place my bets and I'm only placing bets that life is common Don I swung by you pretty quickly so let me give you a chance to speak so life unique or not well the the real question is how abundant is life I mean our rare earth iPods suggested what I think most people believe that microbial life is pretty common but animals you know how abundant are they and it doesn't matter that they're maybe 10 to the 22 stars we will never know anything about that we still know there's life on Mars even though it's really in our backyard the real question is of the nearest couple hundred or a thousand stars is there something like us on them that we can detect with telescope the next century or timescale so it doesn't negative difference if it's in another galaxy or the other side of our galaxy is it nearby that we can ever detect it with techniques from Earth and the other question is can we ever go there or will they come up I go with Paul because if like he said if life is a is a is a vessel that's out of chemical equilibrium otherwise it couldn't really survive if you're at equilibrium with your environment the other word we have for that is dead okay that's what I'm not exaggerating right it when you're in equilibrium with your environment you are the same temperature as your environment you are just simply dead so so so I agree that you there would be a biomarker in the atmosphere of these planets so perhaps well will never visit them in any foreseeable technology we have lined up a carefully carefully designed optical experiment spectra of the atmosphere we can find chemistry absolutely that we know is out of equilibrium that would tell you that there's disequilibrium chemistry going on on the surface and the best version of that we know of his life exactly this is all I just just say that this unique business is if I mean is I what level I were discussing it's like I you unique or I there's a billion that six billion people on the planet so you can say humans are common but you're still unique and I think it's the same there alive strength at birth is unique is that biology in this evolution is not deterministic it's not meant to end at our with us or not in yet but my tent with us the roaches are waiting to take over after we kill ourselves so anyway they're gonna have museums with humans so I think you know that again that that like we have dinosaurs life is probably very common I agree with that but I think that the chance of life would develop into us is extremely unlikely and by that measure I think that the that our earth is unique in having exactly the makeup I think there's a confusion here though so what we're talking about is metabolic processes that seem to be common versus the life forms yeah I've seen any unique ok so evolution is not predictable in the sense that we can't determine the outcome of evolution yeah we're not asking here is there another planet with Dinosaurs that went extinct with an asteroid and mammals rose to become here that's not what we're talking about your exact just a system that supports a thriving biota right I'm limited call Dana yeah so you change your your view absolutely after for the people had disagreed with you you just that backpedal here I just want you to know that's what it looked like okay between you and me it's okay we're good let's take a first question from the floor here um I'd like to thank the panel and dr. Tyson for the tonight's debate according to the app 492 exoplanets he's got the app he's got four yet so so the numbers 492 or under 92 so we should have a 500 party that'll be in an and a half my question goes to the engineering of actually determining the answer to this question given today's technology how far away would you what is the farthest do you think we could be from Earth in order to determine using our technology if there were life on Earth that's an excellent question let me go - let me go - you do it did anyone get the question so the question is here we are on earth and we know there's life and we're trying to determine there's life on a distant planet how far would we have to step away from Earth before our current technologies would not be able to see that there was life here as we know it that's a good question that's a way that's a reality check on what hopes we have of finding earth on a distant planet so the most obvious signature of life on Earth is the oxygen in the atmosphere and the ozone that's produced from it so the question I would rephrase your question is how far away from her could we still detect the oxygen the fact that the oxygen that the earth has an oxygen-rich atmosphere using telescopes like we're developing now and I think the answer is it's going to be pretty far away I would guess you'd be a little more quantitative than that - we got scientists here it's just pretty far yeah yeah oh that's how far away I don't guess as far away as as this planet Gliese 20 light 20 parsecs I'd say 20 light years play like 20 light years yeah no more than easily 25 581 G is 20 light years away is that what I get justice also that's what I just said to my planet but I got a microphone I just said that was an earth-like planet no no we were getting the distance to that star at 20 parsecs what you're thinking we discovered much farther away than that funny funny light you you just have to stare at it the photons coming from the table jekt if you can stare at it long enough it's just time in fact if you get starlight behind it and catch it in absorption and you have a much more sensitive detection okay so you're thinking a lot about that distance you're thinking with the with telescopes we have now which for example Gliese was not detected by direct imaging was detected by as Fred said by velocity Doppler showed a star right so it's not obvious that we can map out the composition of those worlds even that close 20 light-years so I think 20 light-years would be it would be a challenge with current technology and we can imagine interferometers in space and chronographs in space they could do much better and could separate the planet from the start we don't have those in orbit right now nor are they nor will they be in the next 10 years I just served on a decadal survey panel they're not in the cards but they we know how to do them so if the question was how far could we see an earth-like planet say in the next with the technology that we can imagine now and build in the next 20 years in your professional lifetime then I think the answer could be many many times farther than that 20 light years and again oxygen is the obvious fingerprint of life on Earth if you think of the earth before the rise of oxygen as Don said there was a long period of time when birds had life but no oxygen then the fingerprints are much much more subtle and I don't see any prospect of detecting them more than a couple light years even if we can even do that okay next question right here how many how long will it be before we get rocks and material back from Mars to tell if there was life there and do we have to send people to do that or will Rovers and other things be able to do that did they want to catch that question yeah so question is do we go bring rocks back and study it here to be sure whether or not there was life where do we send astronauts there what's the plan for this going forward how long long the the Academy the National Academy will request that NASA bring back samples within the next 10 years that'll be part of the Decatur survey will we be able to do it it's kind of Mars sample return is kind of like fusion it's something that's always you always want to do it and we always think that in 10 years we're going to do it and ten years comes and we think okay another ten years and we're going to do it but it's a little different in that the fusion has some real technical there's instabilities and technological things we don't understand we could probably do the Mars thing if you threw enough money on it the question is yeah good point you have the budget or that's a cultural barrier not if not a technological Bear there are some technological issues as well yeah yeah but there the answer is the same [Laughter] he's right I that's why setups good right here go ahead okay this one's for Fred Adams now that we found the Goldilocks planet what's the probability if you crank different parameters of a solar system to have that found as the what's the statistical idea of finding on the various different kinds of solar systems that are possible something with that kind of a configuration well the honest answer is that we don't have enough from data to but just so I understand the question are you asking now that we have one in the data set yeah can we assign a probability to the frequency of those among star systems depending on which way is depending on how you format a star system okay well we can't answer quite the question you would like because we simply don't know we don't have enough data I mean what we do know is that we've discovered you know almost 500 planets and of those 192 we already know 92 thank you as a can be precise when you can we got it the man told you that's exactly right and of those 492 one is close to habitable if not habitable so you would naively think that there's kind of a 1 in 500 odds on what you need to realize is that when you have one event the error bars on the a monster on the odds are a hundred percent so I wouldn't want to give you any odds because they would basically having a small number statistics the problems what we call we would just sum it up by saying that small number statistics so we desperately need more data to answer your question so we'll get that in the next I would say 5 years and then I'll have something more intelligent to say ok so at that point not that you haven't been intelligent thus far why the truck right ok ok so then you could project that based on certain stars that the stars would generate a certain number of different kinds of client eerie systems and therefore one out of maybe a thousand might have a combination of factors that would give you that kind of a planetary system right if we have enough data we could start to answer those questions what we now have enough data to say is that something like one in five to one and four to one and three stars we expect will have planets of some kind and then some fraction of those will have what we call earth-like planets but we don't have good enough statistics on the Kepler couple should bring in enough planets to really make good tabular statistics on this it's supposed to that's exactly what we funded it we just have to wait only maybe a year or two and we'll know a whole lot more but who's the we here you said we funded it we the right equations on the back of the envelope you can fund a thing but I mean we the country the country good good it's called taxpayers so it so Gliese 581g is in the habitable zone no one knows habit we don't know it has an atmosphere there's an ocean it's a very different world if all the solar systems are like ours and it plans our logarithmically space each one about 70% further we expect the typical stars would take have a couple planets in the habitable zone so don't call these habitable just because they're in the habitable zone means they have a chance of being habitable they also need atmospheres but that's just semantics it's a it's a hat no some some irresponsible journalists said that where was inhabited but most of them most of them got it right that it's now that was a scientist that said not a journalist oh that's never mind was it actually a correct quote of a misspoken stage from an actual psyche word they said that I believe and that's a very important thing in this whole field is belief a lot of this comes down what are you saying she XY are you saying one of our colleagues said that he believes Gliese 581 China has life how two percent chance of life whose I don't know I forgot first author on the paper was that right we'll have to straighten him out yeah yeah you don't have the scientists you never want to overstate 100 percent maybe 99 you don't want to overstate what your data allow you to say otherwise you compromise your integrity forevermore one other way that the earth is unique that no one's addressed and this is the panel is that in terms of the ratio of primary to its satellite the earth to the moon and the effect that the moon's formation ratio the sizes right yes the ratio of the sizes and the effect that the moon has had on the earth over the moon over the billions of years for example it not its formation caused the earth to be tilted and we now have the seasons because of that it created the tides which churned up the basic oceans it slowed the Earth's rotation down from 8 hours to 24 hours which means we don't have 200 mile-an-hour prevailing winds I mean I've known has addressed that and that I'm not sure about gleason but does it also have a large satellite to do those same things that would allow the earth to to this this other earth to evolve Don I want you to handle that so so how important is the moon to everything we just discussed well I think you mean Donner me you oh so I call you know I'm sorry sorry Fred uh-huh well I think Don actually knows the answer is that more than it-- but um well done how important is the moon here the the moon is important but it's probably not a killer if we didn't have a moon we could Fabi surely still have life on Earth but it would be different I mean one of the secrets of Earth has been stable for billions of years Mars hasn't been stable venus has been the staple one of the factors it kept where we venus is stable at 900 degrees I see these because you don't like it doesn't mean it's not stable Venus lost all of its old history the oldest things on the surface of Venus are only about 900 million years they completely turned itself inside out it's it's a reason repaved itself not only is the helis hot place it turns its lid over but so the monas helped keep the Earth's spin axis fairly constant so we don't melt the poles and cause all kinds of catastrophe we just have a different set of configurations and maybe a different trajectory that life would have taken yeah but you don't think it is a deal a deal breaker well it's not not it would it would be a deal breaker for us if the earth started thinning at 40 degrees to the 22 degrees let's get in 2012 that's what's gonna head where this year I'm not authorized with it so so I didn't know that myself I mean I what measure of importance that would have been because just to clarify the moon size relative to earth is largest of all the planet the planet Pluto also has a large moon [Applause] the dirty ice ball in the outer solar system has a large moon you'll never live it down okay right here yes so quick comment about finding life on Mars I think the reason we don't know whether there is or was life on Mars is because we don't want to badly enough as a society with the technology is there we could send more robots but you did people if we really wanted to but we haven't done it because we don't want to badly up but that's actually not my question I'm sorry the wishes that's good because it actually wasn't the question that was an editorial but like my shoes I think everyone would be really thrilled if we found microscopic life someplace but doesn't everybody really want the next Asimov debate to have somebody from our tourists come in it what's the probability of having multicellular life much less intelligent technological life or can that even be estimated well me to invite a microbe as my next guest on is the thrust of the question you what can you can you make any estimate of most people are saying there's probably life yes we're talking about microbes yes is is there any way to make an estimate of what's the probability of multicellular life and ultimately technological life what was the selection pressure for multicellular life oh you're supposed to answer the question yes yes she's you're the mix okay so we don't know really but we think it's because we ran out of certain nutrients and foraging behaviors and behavior in general became more efficient so if I were to take you know at some point you are an energy dissipating organism as Neil you're not in equilibrium I used yeah it's easier words than that but if I were I see energy dissipating organism note did not come out of my mouth okay if I were to take you or Neil or myself and dissolve us into it into our single cells or individual cells and put them out onto a petri dish or individual cells would have metabolism about a thousand times greater than we have as an organism so multicellularity came about as an energy conservation system in places where you have lots and lots of energy there's no selection pressure to ever have multicellularity and this is one of those things that I don't I don't think any biologists really understands why we developed this process why nature created multicellular organisms to begin with they don't diffuse materials very well they're usually limited you're limited by oxygen right now you know where you don't may not realize it so online we have major problems our reproductive rates are much lower it's much better to be a microbe and stay that way for a long time which is why they persist I don't want to be in somebody's digestive system I'm sorry I'm staying I'm staying as human mother multicellularity is not unnecessary thing for life that's a fascinating point about the efficiency of energy I didn't didn't know that thanks next question here yes pertaining what I have to say this is the creator of the contest winning video for the Rose Center turn around it's wave to everybody we flew we flew him in from Los Angeles and he's here for the weekend with family so thanks for coming to this and freer his video was on the Large Hadron Collider there's hilarious it's fun it's accurate and he was inspired by that as well as other science topics but that one particular brought him to create a video on it so now that's your big primo so your question better really be good after this pertaining to the Kepler mission I wanted to know what factors led to the decision for what patch of the sky that we pointed the telescope because correct me if I'm wrong but it's only a small area of the sky that it's pointing yeah who's who can take that I think you'd have to ask the kepler team for details I mean they have it's always an optimization problem of you know you look at a part of the sky and you look deeper or do you look at more of the sky and you look and it's Kepler at l2 on the other side of the moon actually don't remember if the way orbit from Earth it's what it's a thirty it's a thirty inch telescope but it looks it looks like two hundred thousand stars and so it just it just it can't look at the whole sky it looks it's a miracle what it does you know it's science but go on [Laughter] it didn't get hit it has to measure the brightness changes of ten parts per million and they they proved they could do this by doing little holes and plate and putting little wires in front trying a light to it and heating the wires up by running a little current through the minutes well and block out the light if people originally didn't believe that you could do this with existing technology to this incredible position Lister orders of magnitude higher than ever been done before and measures start by so it is a miracle and so maybe the point here is whatever is its field of view two hundred thousand stars are getting monitored and keep in mind you have to continue to watch them because you're looking at the light dim and come back up again it's not just snapshots typically in survey telescopes you take snapshots you move the telescope take another shot to get it here you have to keep at the stars to build your data set so we don't have the luxury of doing that for the whole side sky but two hundred thousand stars that still feels pretty good and that'll all be coming over in the next couple of years once they get there their understanding of their uncertainties hammered out yes next question um this is a kind of more simpler question to the other ones I haven't asked but if um on another earth was discovered and we could it had a special like uniqueness compared to this one could we survive without the magnetic field magnetic we haven't talked about magnetic field make to make how important is the main name field Mars doesn't have one right Mars does not have a magnetic field and a lot of people ask me about that how could life on Mars survive without a magnetic field well Earth occasionally loses its magnetic field we can look back in Earth history and see times when our magnetic field flipped from north pointing to south pointing and during the time in between there would be no dipole field and so and those times in Earth history do not line up with extinctions so I conclude from that that a magnetic field is not essential for life and why you say well it couldn't doesn't magnetic field shield us from radiation and it's certainly true that magnetic field steers solar radiation toward the poles where it forms beautiful Aurora but even without the magnetic field that irradiation will be stopped by the thick atmosphere so I think a magnetic field is nice it's good for compasses it's good for Aurora compass you still use a company yeah I'll get you GPS data after the show pad okay all right then but it's not without a magnetic field life is still possible complex life is still possible in intelligent life is still so people been made too much of the magnetic field I would say then over the years yeah to be clear you know the the radiation that Chris is talking about is what we call cosmic rays so these are particles charged particles not photon radiation yes thanks for that clarification other thing with Larry and they're caused by solar flares tests but the you could argue the other way if you wanted to even though we don't know and that is that the the cosmic rays might cause mutations which could lead to extinctions but they also just might cause evolution to work better you don't know there's also a worry that a lot of people have that if a plant doesn't have a magnetic field when the star is young they're much more active energetically active with all these particles coming out which strip off the atmosphere that may be one of the reason the Mars is a measly atmosphere well but miss isn't it true that half the biomass of the earth may be beneath the surface so what goes on on the surface might just be a irrelevant to most of what's going on I agree that that the that would easily be shielded from the radiation but I think the big question is could we potentially lose the atmosphere by abrasion from from the strong radiation that is otherwise detect around the planet so what you're saying is the high energy can actually oblate the atmosphere off the planet yeah that would be a bad situation Venus also has no magnetic Venus has no magnetic field and it has an atmosphere so and this is what is taught about and you know we're taught that with the big big deal is to keep an atmosphere sighs it doesn't have a nice atmosphere no but bad atmosphere but but if you are big you're a big planet you can keep an atmosphere much better than if you were little depends on lots of complicated factors magnetism is good but we gotta take down with magnitude yeah we're gonna go five more minutes and then we'll break by the way we've convinced the panel to hang out afterwards we're going to go into the whole of Northwest Coast Indians and while several of them have actually written books none of them are here but their other books on earth and the cosmos that you can buy and what people like to do is sometimes get them to sign your program so we'll be hanging out in the car tour if we don't get to each one of your questions but I just want to have a definite ending time here we'll go another five minutes go and try to be quick so that we can get as many going on in five minutes as possible uh dr. Paul I hail from New Orleans Louisiana [Laughter] another have to defend my state in the people of Louisiana that there are plenty of intelligent people in Louisiana if only the Corps of Engineers would listen to us be one so we definitely don't want any Tony Hayward esque type of mentality that we love New Yorkers have tours museums plays me and dr. Tyson you may be confusing with the guns at Texas not of Louisiana so regarding you know be sensitive y'all got wit Marcellus so you know we love y'all I was just kind of I guess it's more of a statement as well that I deal in an area of science but just on another love with medicine and and I love the Vantage of back-and-forth but I think that as long as what's important for science and in all fields is that as long as we keep open and that we don't kind of close things off because you know 50 years ago we would never thought about marine life with bioluminescence or you don't live in near those bent stacks you know down in the basis of the oceans or heart transplants so the most successful scientists are the ones that do have that open mind absolutely and who are willing to listen and not be so you know so set in one path but you know just kind of uh I think that's where a lot of other girls happen well that's why we have we try to get the bleeding edge of absolutely page exactly in you clarified it when you say like what is unique and that's that's one of my thing is well what is unique I mean define unique it it may be different because we may have another system looking at us discussing the same thing but to them what we do is totally um you know off the tortes out of their box across the street as we add our earlier oh okay thanks for your comment Thanks thanks for coming up from Louisiana okay next question sir putting aside the idea of methane based life and oxygen probably being the most possible possibility plug for this museum which has the red band and iron I work by the way in the in the coral of planet Earth and your hall explainer there I am the whole planet okay and it worked it and the idea that biological aspect is what's going to keep the planet going that is as you probably know the red band and Earth hypothesizes that stromatolites a kind of algae developed oxygen which then gave our planet a twenty percent oxygen but these are the life forms you were referring to that would brave a very far at the beginning so the point our life-forms really needed for self-replication I mean that sounds conventions but are they needed for self-replication our life forms needed for self-replication are the algae necessary the oxygen that they produce necessary for our replication we wouldn't be here the oxygen we have only three by the way would stop the so what you're saying is we went through this whole period of time in the history of Earth no oxygen in the atmosphere the algae is making I guess the cyanobacteria whichever it is is cranking out the oxygen and so up what I wonder is if you were sucking away the oxygen while that was happening would we keep that that bacteria there and we would never arisen and that the emergence of oxygen then is that what enabled the complexity of life it enabled the evolution we think of animal life so without oxygen we would not have animal life all animals require a metabolism that is based on oxygen but to get to the point there was a probably between a 600 or maybe even an 800 million year lag between the evolution of cyanobacteria mr. Matt alights the guys that make the oxygen and the actual oxidation of the planet and that that period I mean it's it's an without tectonics again if we didn't bury the carbon we would not have any oxygen to plant so it's not it's not a simple thing just because you make a bug that splits water and generates oxygen doesn't mean you have any oxygen on the planet right now we're breathing oxygen plants are making oxygen the oxygen concentration of the planet doesn't change it hasn't changed substantially for hundreds of millions of years its imbalance there was a one tipping point at about 2.3 or so billion years ago we think where they went from a world without oxygen to a world with oxygen and we never went back again and understanding that period of Earth's history now is really one of the more exciting areas of geochemistry and just to clarify when you said it's in balance do two kinds of balance one is a ball at the top of a hill carefully placed another one is the ball at the bottom of the hill right there both in balance but one is stable because you displace it one direction it goes back right the other one is unstable you displace it it rolls away so you're referring to a stable kind of equilibrium here right yeah okay thank you sir got just a couple more questions here yes hi first I just wanted to thank the panel for a fascinating talk I teach high school in New Jersey and I'm looking forward to telling my students about all this my question is actually that somewhere early in the talk I think it was our moderator who I didn't I didn't do it who was making an argument and said essentially well you're just talking about processes that we already know why can't there be some processes that we just don't know anything about relevant what I want to know is qualitatively how is that different from the people who say oh well we thought we couldn't break the sound barrier and we did that so why is Lightspeed a limit which is an argument that generally is pretty well rejected why is that argument any any more valid than the Lightspeed argument well okay I can tell you that the sound speed those are just really ignorant people saying you'll never break the sound barrier because at the time they made those statements rifle bullets went faster than sound the whip at the tip at the end of a bullwhip goes faster than sound that's the crack of the whip so to say we will never go faster than sound they're making a technologically limiting statement not a statement about the limits of nature to say we don't go faster than light that is not a technological statement it's a statement of the laws of physics so you make an interesting point is that do we know biology well enough to assert that we know the limits of how you would have biology in another planet and and is that the same kind of statement as when we say there's the limit to the speed of light no I think we know if we base life on extracting energy from some substrate like a Sun or from methane in the case of Titan for example then there has to be something if we're going to oxidize methane you can't reduce methane nothing is reduced as far as it will go you're going to oxidize it which is the reaction that a life-form would search for then what is going to be the electron acceptor what are going to be the products and that is really where I'm going from we can think about this in a very very logical way there are organisms on this earth that oxidize methane they produce co2 as a result of that and so we should see in a planet that has life for example carbon dioxide in a world in the sea of methane if there's life forms so as long as life is based on chemistry you have some handle on what kind of byproducts it'll map and these chemistry laws of chemistry are pretty well understood yeah so we think we got some handle on this so the life wouldn't be so different like the blob or something that you would throw throw you into a loop I wouldn't know what the bug looks like I wouldn't know what the organism looks like but I could tell you basically there has to be some rules of the chemistry yeah that's that's chemistry okay good uh all right just two questions just these last two here okay I'm sorry about that but we'll be at the tables you can come up to them go sir all right quick on it Don I think it was you this as the earth has been different through most of its life so I don't think it's fair to compare other planets what the earth looks like now considering that we're in the minority of the time maybe you should judge against what we have been and could end up being I think that came up we agreed that even earth hasn't looked like Earth for most of Earth's history yeah we've been comparing two earth-like planet as of Earth now and she's building it's fair and two we defined earth as or life as being according to Darwinian evolution given you know primordial ooze or given the very early single-celled life forms that abide by Darwinian evolution isn't more complex life eventually inevitable I mean it's nothing another planet-killer arrest everybody everybody invokes this concept of Darwinian evolution and it is true it operates to a very large extent in selection but there is another mode of evolution it's called neutral theory and I'll give you an example neutral theory neutral theory so you have blue eyes and this people in the room have blue eyes people in the room have brown eyes okay your visual acuity is totally independent of your eye color there's no selection based upon your ability to see that brown-eyed people are going to have more acuity or less acuity than a blue eyed person so tremendous amount of variation in nature has no selective advantage and that's just a totally non Darwinian mode of evolution okay so you and I have a life form that we have two arms and five fingers on each hand and so on and so forth but we're not really that different from many other organisms that have similar modes of behavior okay this is what makes us different in a sense is a very funny thing amongst very few mutations we're very very very close genetically to chimpanzees from which we diverged about 6 million years ago so for not even 4 3 genes I believe that 3 mutations point mutations in the fox p2 gene cluster on chromosome 7 in human genome I thought is chromosome 8 you know I just allowed us to speak that gave us speech okay so that is a trivial trivial number of mutations to give us the ability to communicate horizontally abstract thoughts with complex language now that was a transformational mutation that occurred once a singularity in nature so far and what is fascinating about it well it's a simple mutation that had transformational consequence absolutely okay and those are the mutations that we really don't understand what forces these singularities they're random walks and one or two mutations just change changes the world and that's really what the forefront of bioinformatics and molecular biology is that right now trying to figure out what were those key keep freak accidents basically that allow those machines to change the change the world so very interesting that you can have a life form with variation but if it doesn't have selective advantage it's just a variation exactly that it's happy happy being what it is for a billion years right so there are 20 million known genes out there sequenced and I told you only about 1,500 that make the world go round the rest of colors of the eyes the color of your hair that's the the 99.999% of the genes do I we got to make this the last question yes and it's a quick question but is the answer quick see that's what really matters here God goes right here go yeah so if we found any life on any exoplanet roughly how much time would it take for that microbial life to evolve into an intelligent design how long would it take Venus I think that that would depend very much on the flow of energy in that system how much in it is available how there's a lot of energy so if it has a lot of energy that means that you can make many attempts of doing things you can make many organisms many many replications and enhanced chemistry experiment going on so I think I think that you cannot don't you give a definitive answer to that question but you can say that if you have a lot of energy flow in the system it probably go fast if you have very little energy flow in the system it will be very slow if that helps anything and in your cold world untighten metabolic rates go slower when they're cold maybe even if it wanted to evolve something intelligent it would just take too long because it's too cold yeah I think Titan is not a favorable prospect because you don't have the supercharged energy system available to power large animals that we have on earth with oxygen so on Titan I think you would never get beyond microbial life on Mars however she's good enough I tell you I told you about this guy you weren't warned I warned you Mars however you could have had to build up of oxygen very early in Mars just Mars here is this Mars that's I don't think that's wise no you could have had the buildup of oxygen very quickly and conditions for supporting that's large large organisms okay so it's quick okay you somebody said before that life I'm going back to like the beginning not are we finding life but how close are we to getting life and somebody said before it's a very complex chemical reaction how close are we is it like controlled fusion are we that close or closer well let me get making this to making life in the laboratory not close on this not close let me let me put it like he's highly precise answers if I went to if I were to write a research proposal on the or I want to go and study the origins of life I want to try to make chemical reactions in the laboratory because we don't have conditions that allow us to show the experiment can work conceptually this is like throwing darts at a board right so these are highly underfunded areas of research and highly risky one of my graduate students here is working on on on this and sitting right there but the point I want working on it right now right just but the point I want to make is that this story where we came from the origin of life has been out there for a very very long time and are we alone has been out there for a very very long time I'm much more optimistic that in my lifetime we're going to know are we alone than the origin of life is that right I believe that oh wow I wouldn't have guessed that I agree and you agreed go hard whoa let's all thank the panel once again thank you and thank you all for coming we'll see you in the spring and if you want to have if you have more questions you come out to the tables outside we'll be there for you okay drive safely thanks for coming [Music]

Channel: American Museum of Natural History

Views: 214,677

Keywords: Neil deGrasse Tyson, NASA, space, solar system, asimov debate, rose center, galaxy, stars, fred adams, don brownlee, paul falkowski, chris mckay, minik rosing, lefrak theater, hayden planetarium, amnh

Id: 9Ji_GdAk9vU

Length: 113min 26sec (6806 seconds)

Published: Thu Oct 14 2010