Are Aliens Smarter Than Us? Astrobiology Explained

[00:00:00]foreign [Music] this is Star Talk Cosmic queries Edition and you know that means I got Chuck Nice right here hey Chuck hey Neil what's happening you know who Our Guest is for Cosmic queries this time uh it's good old doctor funky spoon David Grimsby um what he's uh he's a resident get the fence out of him get the funk out of my face he's our at large astrobiologist and musician and uh a man who's just all about the solar system and so we solicited questions from our fan base that are right in his wheelhouse and I have maybe five percent overlap with that wheelhouse so that means we'll be deferring to David grinson David welcome back to StarTalk hey guys thank you it's it's great to be here great to see you both yeah we count you as a friend you've been on many many times and uh your on your resume here I've got your senior scientist at the planetary Science Institute and that's in Arizona is that correct that's in Arizona I'm in the Washington DC area through the the magic of uh of the interwebs uh where PSI planetary Sciences to sort of distributed we have people all over the place and uh once a year we get together in person uh just like the old days but just to verify that you're not just Bots yeah exactly or if we are if we are we're very sophisticated convincing ones and I'm reminded you're author of chasing New Horizons I see what you did there because there is a mission to Pluto called New Horizons and as well inside the Epic first mission to Pluto now Chuck you see what he did there he's very uh expectant that there'll be more missions to Pluto right right but the way the the subtitle of that New Horizons was uh screw you Neil that was uh that was the I see are those implications Chuck that's the implied subtitle come on actual sometime yeah but let's not forget about uh my favorite Dr Funky spoon book If I recall correctly uh is Earth in human hands because it's all about how we are shaping this planet and if you want to know some great information about climate change and the anthropocene you should check out that book man because it's uh it helped me it's really very cool wow I didn't know you're now his agent okay good to know that Chuck's just my my like Prime audience if if he likes it then then I know I did something right so well tell us about tell us about that book because if you're if you are a planetary EX expert then Earth is simply another planet and then you get to compare it but you know this it strengths and weaknesses susceptibilities he does that in a book actually that's what I meant so I just want you to let's take me there yeah well so so I I just thought it would be I thought it would be cool to uh look at um sort of the question of you know the perennial question of what are humans and what makes us different if anything it's almost the uh the astrobiologist's view of you know if you were an alien with a long attention span watching Earth and then in this recent stretch of time you would have seen something really weird happen to our planet that has never happened to it before you know where the night side lights up and the atmosphere changes and every Everything Changes and and what does that sort of look like from a planetary perspective that was sort of the goal of Earth and human hands okay cool cool and when was that published that was published in 2017 2017 and the date on the New Horizons book that was um 2018 that was a busy little stretch for me okay all right I'm still recovering from all that very cool and we also have you listed here as a musician are you active or are you just sort of play at home where no one's listening well actually one of the things that's wonderful for me and I think for a lot of people about this stage where the pandemic maybe isn't over but it's easing up a little bit is the return of live music and I've been really enjoying that both as a listener and fan and also as a performer and I have been playing I'm I'm in a new band actually here in the DC area we're called the easy way and it's kind of a funk soul thing and it's uh we've just started playing we played we've played four gigs now so that's that's really fun for me is to be back out playing a little music and are there any other scientists in the in the band with you there are actually uh well no but uh one one of the other guys that our lead singer he works at Nasa he's not a scientist but he's a NASA dude so so we do NASA does represent so so Chuck you got questions for us I haven't seen them yet I don't know if David has uh I'm sure uh I listen I haven't so okay all right I don't think anybody has this this is a cosmic query so tell us what you got here we go you want to jump into this let's do it let's uh let's pop things off with Trevor C Mills Trevor says hey Dr Tyson Dr grinspoon as well as Chuck uh I hope this finds you well this is Trevor from Augusta Georgia at what point in our search for extraterrestrial life do we start a search for non-carbon based life good candidates from silicone so okay that's a good question you know the thing is I would say there's not one specific point it's almost like more a perspective we have to keep in mind and remember that this search needs to be conducted with the the humility of the realization that we don't really know what we're looking for we have some hunches about what's Universal uh about life and we know that carbon chemistry in water is a basis that can work and we have uh good reason to believe that that could be functioning elsewhere because the conditions are uh are available for other places so so it's a good thing to look for because we we know it can work and we know we sort of know how to look for it but um we should keep in mind that we don't have any solid reason to believe that that's the only kind of life we haven't thought of any other nobody's constructed or or invented in a lab another kind of life that works as well but that just that could be because we're dumb not because the universe doesn't know I do it in our movies our movies we do 100 times over right yeah it happens in movies and and you know there is this move in NASA astrobiology um to look for what we call agnostic bio signatures which means uh not a trying to assume as little as possible and looking for sort of more Universal things that may not depend on carbon you know but then you get into this question what do we even mean by life and what does life do but you could talk about um you know chemical disequilibrium life-changing the chemical balance of its environment in a way that non-life probably doesn't and if you go that route it doesn't have to be carbon based it just has to be something that's multiplying itself and and uh using energy and so so we do have ideas about how to look for non-carbon based life and and I think we it's good to be reminded so so thank you for the reminder that we should keep keep that in mind as we search but our search does tend to be focused on quote Life as we know it partly because that's what we know how to look for so often people will swap try to swap silicon in for carbon in the molecule and many satisfy Sci-Fi movies that have attempted other chemically based life have done that with silicon and can you tell me why silicon would be such a attractive next next option yeah because in some ways silicon um is a lot like carbon in that you know if you look at the periodic table we all remember the periodic table from the wall of our our science classroom and it's got you know in the upper left it's got high hydrogen and then below hydrogen are all the things that Bond like hydrogen with like one electron and sort of in the middle of that chart is carbon at the top and then below it are all the things that Bond like carbon carbon makes four bonds with other things and that's the basis of of organic chemistry which is the basis of life so you look right below carbon the next thing down is silicon you think okay silicon that's going to be kind of like carbon maybe you can make biomolecules out of that so there's a good logic to it but the problem is uh silicon bonds are not like carbon bonds what's great about carbon is not just that it bonds to four other things so it can make this whole you know um complex Lego set of of molecules then it doesn't sound like it it it it it works it doesn't sound like it it sounds like it's people making a leap because it's similarities but that's like me saying you know Obama has large ears he's black I could be president you know no no Chuck no you can't you cannotize it okay it is kind of like that it depends on what what features don't agree with chuck on that don't I don't know I'm sorry Neil But Chuck has a point here on the show and the fact that the fact that silicon bonds before the things makes it like carbon but the problem is the nature of those bonds carbon bonds are also kind of floppy and loose and can you know Carbon can get into all these like weird configurations which make proteins and things silicon bonds tend to be really stiff and you know they don't make those nice uh complex configurations the way carbon bonds do so those who can't see David greenstone was just Vogue shaping his hands around his face chemicals fabricating the flexibility or rigidity and strike a silicone silicon likes to strike a pose stick to it yeah okay gotcha and and so that's less flexible when life is experimenting on the diversity of what it may need to thrive in an environment and I don't think it makes like carbon makes polymers you know these big molecules where it's not just carbon but it's attached to lots of other things silicon it makes you know silicon oxygen chains and things like that but I don't think it makes the kind of just diverse molecule set that makes carbon so good for life I would add just from an astrophysical point of view there's like five times as much carbon in the universe as there is silicon so you don't even need to appeal to Silicon because carbon is there for you and it's your friend so to both of you with respect to this is are there any conditions in the universe under which circumstances cause different reactions to these elements where they might behave in such a way to do something like make life or is the Periodic Chart the same no matter what no matter where well the Periodic Chart is going to be the same uh not for the elements not the chart I'm talking no but I mean but but I mean the elements are going to be the same but your question is good are there conditions in which the reaction types the behavior is going to be different and the answer is yes there are conditions in which it's different and that's why we have to be careful to not be to Earth Centric but has anybody come up with a set of conditions that we're likely to find somewhere where you can show that silicon is going to do the right thing to make life the answer is no but that maybe just again be limited on our imagination okay is any as any good scientists you gotta sort of not only know your limits but be prepared to shatter them as you as you take every Next Step going forward right Chuck you got another question for it all right here yeah yep yep this is uh Emily either Talus or talius one or the other uh because it's a double l so a high Chuck and Neil greetings from Paris France so maybe not either one of those in Productions myself you probably Maybe not maybe not and then she goes uh oh look at this Chuck feel free to butcher my name I can't wait to hear what you come from setting you up oh jeez that was good okay preempt preemptive uh consideration yeah tell me about it all right she goes I was wondering what would happen if we were to discover intelligent life outside of Earth of course but let's advance than we are first how will we discover it and confirm that it is indeed less intelligent well that's pretty easy and second once confirmed what would the next steps be is there a protocol for Life Discovery um yeah first of all I love the question and it's not one we think about very much because there's a set of assumptions um that are almost unspoken because of how long we've been assuming them and how frequently we assume them which actually David they'll remain unspoken until we come back from this break yes they will remain unspoken a little longer oh just a little longer just a little longer let's find out about the unspoken protocol that's the next installment of Mission Impossible David's unspoken protocol about encountering life I will be right back after this first break we're back Star Talk Cosmic queries with David grinspoon a friend and colleague and he's an expert on the solar system in astrobiology and all kinds of cool things such as that uh David how do we find you on social media uh well I'm I'm still on Twitter uh at least today and that's that's um at Dr funkyspoon um doctor that's why we call you that Dr Funky spoon yeah and I'm on um I'm on uh Facebook just under my name and and uh I'm on Mastodon now too uh which is I'm Dr Funk spoon at koto.org q-o-t-o funky or Funk spoon funky funky funky smooth okay yeah all right I'm hedging my bets okay so Chuck we left off with a question about from Emily talia's tablet she's from France was Emily yeah uh Emily but so so she wants to know what happens when we find life that's less intelligent than it is right that's hardly ever addressed in a Sci-Fi storytelling yeah because no one could imagine that we could be smarter well it's harder yeah it's hardly ever dressed in sci-fi but it's also hardly ever addressed in um in seti itself because there's always this assumption that anybody we find is going to almost surely be more quote advanced than us or have been around as a technological species or civilization much longer and there's a good Logic for that because you know on this for one thing on a cosmic time scale we're just babies right you know four and a half billion years of Earth four billion years of life depending on where you you started you know a couple million years of being human and a few hundred years of being technological and less than 100 years or 100 years of being radio friendly you know so so we're babies and so that's one thing just time scale wise but also anybody who's good at Interstellar communication or certainly anybody who's traveling um in an Interstellar scale is almost surely uh has technology that we haven't developed yet you know so there's there's good logic there so we always imagine that we are the neophytes and they're the wise ones and that there's an asymmetry in contact in that direction and you know statistically I think it's a pretty good argument but it's an interesting question what if we meet somebody who's uh you know there's a pretty narrow range there where they could be dumber than us and still considered still considered intelligent but what if we what if we did and yeah and how would we find them because presumably then they wouldn't have traveled here so we'd have to stumble upon it or responded right so even even if they're not traveling here yeah but what if we got you know what so what if we got lucky it sort of stumbled on a civilization that was sort of just becoming technological but hadn't become Interstellar yet um it seems like that would just be a tech level that's not an intelligence level no that's a good point too because because you could argue there's you know there's always the whales right and the Dolphins they're really intelligent they arguably have a civilization in it I saw that Star Trek movie the same whale Star Trek movie yes yeah yeah so we could certainly find intelligent life that is not uh technological at a level we are um and you know as far as protocols it's there's it's pretty vague you know there are protocols for seti if we think we we found something a radio signal ready to search for extraterrestrial intelligence just the general yeah a term for that right yeah so so this the seti the search for extraterrestrial intelligence Community has protocols that if somebody thinks they found a signal then you don't announce it immediately to the public first you verify it and you get another Observatory to also find it so you make sure it's not some weird mistake that your Observatory is making in some local interference but then once you're sure um then the the protocol is complete transparency you alert everybody you know so uh unless the Men in Black get to you first yeah that's right with a flashy thing yeah that yeah so um you know and then if if somebody comes you know and lands a spaceship on Earth uh and context is we there's no real official protocol for that because it's not not something that's just been uh you know you can argue whether it should be or shouldn't be but it hasn't really been taken seriously Enough by the the sort of seti and scientific Community to develop a protocol for that all I know is that in today's world if the aliens land and they say take us to your leader nobody's taking them to the White House yeah that's so true it would present a conundrum where do you take them you take them get a beer at the Corner Pub I imagine that my my fantasy is that they would land and then we find out that we're so insignificant that they're actually filming a reality show oh oh with them Among Us yes exactly okay like that is that's what we rate as like hey let's go down there and like like basically they're the Ashton Kutcher of the universe and we're the ones that are being pranked we're pro we're basically props we're props we're we're straight up props so David I just want to add that if we count chimps as sort of the next smartest species to us just just for the sake of this for this example we can't have a meaningful conversation with him think about it and we've got 99 identical DNA so if if we find another species that's sort of not as smart as us what evidence do we have that we'd be able to communicate with them or worse yet finding a species just that one percent smarter than us than we are to chimps what hope do we have of them even being able to communicate with us because our simplest thoughts would transcend our most brilliant thinkers yeah your example of chimps really uh is an interesting one and it kind of illustrates that something very recent has happened uh here on Earth with humans that uh For Better or Worse where we have the these qualities of of language and culture and and so forth and you know not just I mean chimps you can argue have a kind of language but the sort of syntactical language and ability to express abstract thoughts and all that maybe you know it's pretty it's pretty new and it underscores how unlikely it probably is that we would connect with somebody else out there who seemed like an intelligent uh civilization uh but also was less um capable than us because you know it really illustrates that maybe we've just passed some kind of threshold and on the other direction yeah so what if somebody is to us as we are to chimps that may be possible but it may also be that this sort of threshold is something that one once you're over it then maybe you sort of can communicate even if you recognize that these guys are geniuses compared to us that's David's human ego yeah we we hate that thresholder we could communicate with any intelligent species smarter than us right you keep thinking that David I said maybe or maybe not maybe maybe we're dumb as rocks compared to just about everybody in the universe I like that one that's mine that's the one there you go Chuck keep them coming all right this is Sandra baliani Sandra bayani says good morning or evening wonderful Star Talk hosts and listeners this one came to me as I was flying to Seattle and looking out the window love it love looking out the window yeah why are black holes generally situated in the center of galaxies why that specific area and yes this is the kind of stuff that I think about while I'm on planes looking out the window that's good because a whole lot of stuff you can think of to create anxiety and things yeah if you can think about black holes on a plane and not feel anxious that's that's good so David I should probably take this one right yeah I was going to say that uh we we actually have an astrophysicist here and it's not me uh so a black hole our understanding of black holes tells us that you can get it from the death of a very high mass star the sun is not among them and high mass stars are very rare so these would be stars that are dotted around the Galaxy from a black holes that is the remnant of a supermassive star that lived out its life and died and in the final collapse it collapsed all the way over black hole we expect those black holes to be pretty much rare but everywhere if if you can imagine if you can picture that so so in other words wherever you had Stars being born you'd have like maybe one of these all right so there are fewer of them than all the total Stars by far but there's no part of the Galaxy that would be without them so that's for start so that's a one kind those are called uh Stellar black holes then just empirically we discovered that the centers of galaxies have black holes in them we just it was a discovery in my life while I was in graduate school this discovery took root and we say well we've got one in our galaxy and one in a nearby Galaxy and then well there's another galaxy over here we we can get data and we show a black hole and so we extrapolated we said if it's in these three galaxies it must be in all galaxies because it's hard enough to get those data and those galaxies were very different from each other so then we just went on the assumption that every big Galaxy would have a supermassive black hole and sure enough Hubble Telescope gets launched and every Galaxy we look into and have the quality of data to know they've all got a supermassive black hole and we do not yet know how they were formed and the James Webb Space Telescope is exquisitely tuned to see the birth of galaxies and from those data we might be able to see material collecting in the middle to form the supermassive black holes that dot the center of every Galaxy and again a sense of it a black hole Stellar black hole might be five ten times the mass of the Sun but the supermass of black holes in the centers of galaxies is hundreds of thousands up to millions of times the mass of the Sun so if it's consistent that it's the death of a star that makes that do we see stars that have that mass in the universe that might be able to create the supermassive black hole that coalesces a Galaxy no no okay yeah it starts to give out at about 60 to 100 times the mass of the sun we don't find Stars more heavier than that so we're not going to find a billion times mass of the sun star right just have never seen that and so that's what we think something else is making them that's it has something else yep that's that's that is wow that is a wonderful mystery yeah yeah well the universe Grims with Mysteries that's why David and I have a job I I love the fact that for the supermassive black hole it in our own Galaxy we can actually watch the Stars orbiting it so and in a Nobel prize winning observations uh yes we can you're watching these stars do these loops and loops and there's nothing there in the middle nothing right it's enough to make you really believe and you run the math on the orbits and the speeds and and the distances and you get a black hole you get a black circle yes it's not cool it's not a NASCAR track it's a black hole that's very cool all right here we go um this is his name is on another page Gavin mallow and Gavin says greetings from Beaver Creek hello David Neil and Chuck and that's Beaver Creek Ohio I forgot the Ohio part okay I'm curious about the possibility of Life on an Earth-like planet that would lack the protective sleeve that Earth's atmosphere and magnetic fields Supply us What would life do to accommodate these relative extreme conditions could anything on Earth potentially be transmissible to an environment as such I like that yeah David we got these we got these protect you know our atmosphere protects us from meteors it protects us from UV light it's you know so we're here uh by the grace of the atmosphere and so if there's a planet out there earth size Earth gravity Goldilocks zone maybe and doesn't have these protecting forces what what do we do yeah that's that's a great question I'm I'm less worried about the magnetic field part which is the other thing that the questioner asks because we're learning more that makes us wonder how important magnetic fields are in protecting the surface of a planet uh we used to say that without that it was the lack of a magnetic field that made Mars lose its atmosphere for instance but more recent observations have made us question that and the role of a magnetic field in protecting the atmosphere itself is not so clear and then there's the example of of one of my favorite planets of Venus which has no intrinsic magnetic field but because it has a thick atmosphere it's still protected in fact Venus develops what's called an induced magnetic field where just the the solar wind itself sort of makes the upper atmosphere charged in such a way that it starts acting like it has a magnetic field and David if memory serves you wrote a book on Venus too this is correct yes sorry you wrote a book on Earth about Venus that's right I was out on Venus when I wrote the book but I wrote a book on the subject of Venus at the time so that book was what that's that's Venus revealed revealed there you go okay yeah so you've been at this for a while very yeah yeah so so magnetic fields I think life could life would find a way but um but an atmosphere fills so many roles not only does it protect from dangerous radiation ultraviolet light and cosmic rays but of course it also um serves to transport um you know think of Earth and the the role of oxygen and carbon dioxide and plants and animal life the transporting of um chemicals that are involved in in the metabolism of organisms of you know trading energy between molecules and so forth It's hard to imagine life evolving on the surface of a planet without an atmosphere now of course there are places in the solar system without atmospheres where we think there might be life on on the inside like say Europa and so one could imagine an Earth-like planet without an atmosphere that still had the chemical stuff happening and the and the and the energy transformations on the inside so that maybe you'd have internal life um in in the interior of the planet but but it but an atmosphere is so integral to the kind of life that we have on Earth that it really sort of stretches the imagination to to think of how you would get a biosphere without an atmosphere and and and there's nothing wrong with stretching the imagination I mean this is true that's why we like these kinds of questions yeah yeah yeah Chuck we got to take a quick break okay David we'll be back in just a moment for our third and final segment with David grinspoon on Star Talk we're back Star Talk Cosmic queries all about the solar system and searching for life and astrobiology with one of the world's leading experts on these very subjects David grinspoon a friend and colleague at the planetary Science Institute itself based in Arizona but he is distributed uh he's part of the PSI at large community based in Washington D.C always good to have you David you're a friend of our show and thanks for responding to our always great to be here with you guys yeah let's make this kind of like a lightning round all right and we'll speed it up as we go along because we only got through like five questions and we got more tons of them let's keep going all right here we go Eric shurikan or sharakan says uh Hey from Boston what does Dr David grinspoon think about the James Webb Space telescope's recent exoplanet Discovery particularly that it appears similar to Earth in size and in composition yeah David you know when we designed the damn telescope it was to look for Galaxies at the edge of the universe and then you planet people are starting to use it to like look at stuff right in front of our noses so who when what in the dark of what night did that when did that happen yeah all right well first of all Boston my hometown yay go Celtics and um the uh it's it's wonderful what I think of that is you know like uh as Neil implies the the the web was not designed to uh look at exophantis it was designed for uh galaxies and other things like that astrophysical targets but um you know I chalk it up to the fact that the universe is just so incredibly productive when it comes to planets much more than we thought even when people started designing the web and so it in a way it's luck you know there turns out Webb is sort of marginal for exoplanets but there's so many good targets that we're starting to find them and they the exciting prospect now is that we can start to see what their atmospheres are made of even though again web is not the ideal instrument for that and we've got other ones of course we want to build in the future that will be more more ideal we're we're going to learn some really cool and important things about our our planets in uh in nearby star systems and that's pretty opportunistic and that that's good absolutely good time absolutely all right keep it coming all right let's just keep going succinct answer David okay look through this third round okay go keep it a move and Kyle Marston says hey yo hey yo hey I didn't say that he did uh how many Earth-like planets do we know about currently that reside in habitable orbits is there a number uh you know there's there's a lot of marginal ones uh I would say um I would say a handful you know um which is which is pretty good because when you come when it comes to saying habitable orbits some of them were sort of guessing because it really depends on whether they have an atmosphere or not and what the details of their climates but there's a you know there's a good a dozen or so that um seem like pretty good with candidates they're 5 000 planets in the catalog right now and you tell me there's only like a dozen that are Goldilocks Planet I'm saying ones that we and it depends what you mean by Earth-like okay these are these are all gray areas but I'm saying I'm saying roughly earth-sized and definitely uh good candidates to be in the habitable zone and maybe have liquid oceans and things like that it's a small but growing number okay all right so that would be if we did it in percentages it what's 10 out of 5 000 so what is that it's one out of 500. so that's still pretty low that's like a fifth of one percent right yeah but you know but a lot of those 5 000 are ones that that will could be these are I I I'm giving a conservative number for ones that we can say yes that's earth-sized and yes that is so there's really in the running in the running yeah absolutely but it's still big news it's still big news when we find one yeah that's why it's so exciting that you know it's this one that was just mentioned because like oh yeah that's earth-sized and it seems to be in the habitable zone that's it's still news yes yes which is a good thing it means people are so excited and there aren't enough for them to get bored with it yet okay Chuck keep it coming all righty here we go this is I I think I mean you you maybe you're the reader here so yeah it's always what you think okay you're right exactly yeah I'm gonna tell you the truth I really don't think that but that's about as close as I can come okay uh he says hey Neil hey David and Seth MacFarlane's the Orville 25th Century life has progressed far into the Galaxy solve societal health and technological issues and eliminated money as a form of currency do you think this future is viable and what steps do present-day humans need to take individually as well as on a larger scale to walk towards that goal how can we push for science literacy globally wow okay so David answer that in three sentences if you can uh I I would say in three senses yes I think it's possible though not assured um and that the path is not going to be smooth between here and there and that the the key is some sort of a globally enlightened Society where we uh guide ourselves with the recognition that we are one planetary species uh despite all of our wonderful differences so it's a guidance Force operating on our future decisions yeah right well there you go here's your answer we're screwed okay and I think just just to remind people I think the original Star Trek after which so much of the Orville is so much of it is inspired forces operating within the storytelling of Orville if I remember correctly the reason why there's no money is because they they someone developed a replicator where you if you need another one of something just make another one in it so you didn't have to go out and buy it or earn money to obtain it so it's post post scarcity correct a post-scarcity world right where anything could just come out of a box a machine that you you create and so that changes what people care about what they value and all the right but one of them is you don't need money it's interesting because money is just a belief system anyways we all fool ourselves into thinking again it has value so it does have value right so we could always change our minds collectively about that right right yeah and the other thing too is once they got rid of money they people started to do what they wanted to do which so you naturally end up with a passion for life because everybody's doing what they want to do rather than what they have to do in order to pay the rent exactly wow okay but then how do you explain ferengi's well yeah they're greedy little bastards pretty little bear they have it all and they still want more you know but Chuck what you said is deep because it it what it would do it would Liberate the creativity of every citizen of the world right yeah who contribute in whatever way best floats their boat and they'll probably be better at that than anything else they would have done right because they'll do it because they want because yeah yeah exactly they have to indeed I like it I like it I think I think we should just like start that world right now oh that's great and on January 17th a revolution took hold fire across the face of the globe all right so this is Cameron Bellamy who says greetings from Baltimore Maryland what aspects of a planet's climate are planetary scientists looking for when evaluating planets for potential to support life additionally how close to these planets need to be to Earth to look for these aspects in the planet's climate I like that yeah yeah so that's it's it's a good question so I mean the basic factor that we're always very focused on is a climate in the range where water would be predominantly liquid and again that could just be our own bias because you know as we talked about it earlier maybe we're not smart enough to think of other kinds of life that don't need water but Earth so much of what makes Earth the way it is is because the climate balance is such that we live on a water planet and that is in every cell of your body is liquid water interacting with organic molecules so so that's the number one thing there's enough greenhouse gases um the good carbon dioxide yeah exactly the a good amount of greenhouse gases carbon dioxide water a little methane sulfur dioxide these are the gases that absorb infrared radiation and make a planet warm but not so much that you have a Venus that's just too hot for liquid water so that that's the sort of prime directive if you will for for habitability um and what was the second part of the question um what do we look for um to to um oh how far away how far away yeah yeah um again you know with the tools we have now we can there's it's it's very difficult to um tell what's in a planet's atmosphere unless it's not just distance the geometry has to be right if we have what we call a transiting Planet so it passes in its orbit right between us and its star then you can look at the radiation coming from that star as it passes through the atmosphere and see how it's filtered out and what molecules are there but it's easier to do that if you're you know within a few hundred light years than if you're thousands of light years but crap but if we as we get better instruments um that we want to build in the future we'll be able to greatly expand the number of planets we can do that for now just a quick addition here I remember watching Star Trek and just you ever noticed David Chuck they never wore spacesuits when they went down to Planet surfaces right have you ever thought about that [Laughter] at some point the Spock would say uh it's a oxygen nitrogen atmosphere Captain right and but I would hear that and it was as though all we have to do is find an oxygen nitrogen planet to move to and then I realized and David correctly if I'm wrong here if it has oxygen something's making the oxygen so so you are already looking for planets that had some kind of life forms on it to create that atmosphere in the first place it's not that there's all kinds of random atmospheres that exist on all the planets and pick the ones that you happen to be able to breathe this this active stuff going on there is that fair yeah the reason why the reason why we have a breathable atmosphere is because there's life here right oh wow and so any Planet you find with that kind of atmosphere would be very surprising uh like like you say Neil what what else would be making an atmosphere with just that mixture it's hard to imagine that it's not brimming with life right right right so cool okay a couple more Chuck man we're blowing through these very nice right yes we are yes we are here we are uh this is right now we're we're we got to speed up even more so David sound bite mode okay remember all right so ABC News just put a microphone in front of your lips and they're going to sound bite you for the evening news so here it is all right uh hello Chuck hello Neil hello Dr Funky spoon um okay here we go does weed still work in space or the THC crystals too fragile for space what temperature uh what hemp crop would be great best to grow on Mars I'll say I don't know that the experiment's ever been tried but in all seriousness one thing I wonder about NASA never took weed into the space station not that I know of but I will say in all seriousness one of the big problems with astronaut health is eye pressure ocular pressure and one of the things that is well established that cannabis does medically is good for glaucoma because it reduces ocular pressure so I've always thought and I've kind of whispered this to a few people at Nasa but like why don't you try that right on okay yeah yeah and you don't you don't have to you don't have to smoke it we have gummies about the soils of Mars can you grow anything there yeah I mean if you could grow uh anything I mean the thing you know cannabis is just another plant so if you grow tomatoes you're going to be able to grow cannabis there it's okay so whatever the soil the soil by itself as of now probably isn't very uh isn't very fertile you know because it doesn't it doesn't have Organics from the book and movie The Martian yeah but it could certainly you could certainly mix in a mix in a little uh either human generated or otherwise generated fertilizer and grow stuff on Mars human generated fertilizer fertilizer yeah not the problem we call that hgf nice nice one last one Chuck this one here we go this is uh akshat oh man it actually take you as long to read the name as the question itself because I don't prepare [Music] um [Laughter] uh uh patrika that's it who says this hey hello and greetings from India I was wondering whether Venus was once a habitable planet and their civilization was there uh living on the planet but unfortunately they destroyed themselves due to extreme climate change what yeah history have to the evolution of the entire planet thanks and I love the show it's from India yeah yes growing their presence in space with satellites and space missions and things yeah and they have a Venus Mission that's announced an Indian Venus mission where that came from they're very good okay but um so so company of space-faring Nations short answer yes indeed a short answer I've often wondered that myself but it's true that we think that Venus probably was habitable although that's one of the motivations for our upcoming missions is to determine was it really we think it had oceans in Boston but we wanted gather the evidence to be sure of that um we generally don't talk about an ancient civilization on Venus although one has to admit that we have not explored the planet well enough to rule that out okay where what you said you don't talk about it that implies you don't talk about it in public or something no no no I said that Chuck yeah we don't talk about it we don't I just mean that's that's not a monster in the Disney movie we don't talk about Bruno but yeah I meant that's not amongst our most favored hypotheses but it's certainly not that thing we can rule out thanks for letting me clarify that yes thank you very very much there but clearly Venus does have a runaway greenhouse effect and they're just worried maybe the the Venus has knobs that got turned right that had it become what it is and we should look at those very same knobs here on Earth yeah no I mean a serious answer is that by studying what happened to Venus we can be better prepared to understand changes in Earth's future and that indeed is one of the big motivations for understanding what happened to The Climate there now is that is is is runaway greenhouse effect some something that can happen under the conditions that we have like our planet could undergo the same thing could that happen I'm just saying like not not that we make that that it is going to happen but is it possible here that people have people have looked at this and the answer is if you burned all the fossil fuels on Earth of course you would make things awful and uninhabitable for humans but you probably would not trigger a Venus style runaway greenhouse effect where all the oceans boiled off but but in the future as the sun warms up which it is slowly in you know a billion years or so um then there probably will be a runaway greenhouse effect on earth like there was on Venus in the past so if we wait long enough then the sun will help us do that so you hear that Chuck when an astrophysicist says in the future his next phrase was a billion years always yes there's some serious ass future that we're talking about exactly yeah we have more immediate problems but none of unless it's still interesting too much get David's blessing on this comment before we close it out so David in all my readings on this I I agree that if you extracted all fossil fuels and burned them all with none left the Earth would be hotter but you would not have the runaway greenhouse effect experienced by Venus what you would need to do is um somehow dissolve all of the world's Limestone and other repositories of carbon that's beyond just fossil fuels or fossils right and and if you put all of that carbon added to the carbon that the fossil fuel burning would then we could become a twin of Venus in that way is that is that fair yeah I think that's right because then I mean Venus has sort of uh like a hundred hundred bars almost of CO2 which is 100 times the atmospheric thickness of Earth if you burn all the fossil fuels you're not going to get that much carbon in Earth's atmosphere but yeah if you dissolve all the Limestone and sort of took all the carbon in Earth's crust and somehow put it in the atmosphere I don't think anybody should should try this yeah don't try this at home then then I think you probably could turn Earth into Venus yeah okay all right so we're not doing that for sure but but the one thing we know for certain is that greenhouse effect is from carbon in the atmosphere that is just the way oxide carbon dioxide so carbon dioxide in the atmosphere done deal Greenhouse Effect and we know that we are doing that through burning fossil fuels here right now right absolutely absolutely we're going in that direction and it's the wrong direction for us okay there you go for our survival all right all right we got to call it quits there on that down I was going to say I had a truck I had a good news good night a couple of minutes ago and then you have to just take it down a few minutes ago we were abolishing all money and like liberating human creativity in the last those are the breaks this is start talk Cosmic queries one of our favorite variants on the Stark talk franchise Neil deGrasse Tyson here your personal astrophysicist I want to thank David for coming back to StarTalk he's a friend of the show and of course Chuck Nice always good to have you there always a pleasure as always all right