StarTalk Radio - Cosmic Queries – Silicon Aliens with David Grinspoon

Episode Date: January 31, 2023

Can there be life on planets without magnetic fields? Neil deGrasse Tyson and comedian Chuck Nice discuss exoplanets, extraterrestrials, and answer extraordinary questions from our fans with astrobiologist, David Grinspoon. NOTE: StarTalk+ Patrons can listen to this entire episode commercial-free here: https://startalkmedia.com/show/cosmic-queries-silicon-aliens-with-david-grinspoon/Thanks to our Patrons el EC Podcast, neutronforce, Jim Crutcher, S Mokry, and Sly Sparkane for supporting us this week.Photo Credit: NASA/Goddard/Francis Reddy, Public domain, via Wikimedia Commons Subscribe to SiriusXM Podcasts+ on Apple Podcasts to listen to new episodes ad-free and a whole week early.

On the next episode of StarTalk, it's a Cosmic Queries edition with, of course, Chuck Nice. And we have as our guest, David Grinspoon, a friend and colleague. His expertise is on exoplanets, the search for life, and astrobiology. And we had some great questions coming up for you. Like, is carbon-based life the only kind of life that can exist? Is it the only kind of life we're searching for? Might we be missing something? And if we do find life, is there a protocol?

Also, what would an Earth-like planet that sustained life be like if it had no atmosphere? And will Earth ever become Venus? With a runaway greenhouse that's nearly 1,000 degrees Fahrenheit. On this next episode of StarTalk. Welcome to StarTalk. Your place in the universe where science and pop culture collide. StarTalk begins right now. David, welcome back to StarTalk.

Hey, guys. Thank you. 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 on your resume here, I've got you as Senior Scientist at the Planetary Science Institute. And that's in Arizona, is that correct? That's in Arizona. I'm in the Washington, D.C. area through the magic of the interwebs. We're PSI, Planetary Science Institute is sort of distributed. We have people all over the place.

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 it's inside the epic first mission to Pluto. Chuck, you see what he did there. He's very expectant that there'll be more missions to Pluto. Right, right.

By the way, the subtitle of that New Horizons was Screw You, Neil. That was the- I see. That's implicated in the demotion of- Chuck, that's the implied subtitle. Come on. Oh, the actual subtitle. Okay, I'm sorry. Yeah, but let's not forget about my favorite Dr. Funky Spoon book, But let's not forget about my favorite Dr. Funky Spoon book, if I recall correctly, 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 helped me. It's really very cool. Wow. I didn't know you were now his agent. Okay. fine. I get to know that. No, Chuck's just my prime audience. If he likes it, then I know I did something right. Well, tell us about that book.

Because if you're a planetary expert, then Earth is simply another planet. Then you get to compare it, you know, its strengths and weaknesses and susceptibilities. He does that in the book, actually. That's what I meant. So I just want you to, let's take a look for a few minutes. Yeah, well, so I just thought it would be,

I thought it would be cool to look at sort of the question of, you know, the perennial question of what are humans and what makes us different, if anything, from the perspective of astrobiology and planetary science and try to look at humans as this sort of thing that's happening to the planet and how that fits into history. And then hopefully how that view of ourselves can help us in a constructive way, think about our future, you know? So it's basically, it's the astrobiologist view of ourselves can help us in a constructive way think about our future. So it's basically, it's the astrobiologist view of, if you were an alien with a long attention span watching Earth,

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, where the night side lights up and the atmosphere changes and everything changes. And what does that sort of look like from a planetary perspective? That was sort of the goal of Earth in Human Hands. Okay, cool. And when was that published? That was published in 2017.

2017. And the date on the New Horizons book? That was 2018. That was a busy little stretch for me. Wow. 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 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 is 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 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 we've just started playing. We played four gigs now. And are there any other scientists in the band with you? No, but one of the other guys, our lead singer, he works at NASA. He's not a scientist, but he's a NASA dude. So we do, NASA does represent.

So Chuck, you got questions for us. I haven't seen them yet. I don't know if David has. I'm sure, listen, I haven't. So I don't think anybody has. 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 pop things off with Trevor C. Mills. Trevor says, hey, Dr. Tyson, Dr. Grinspoon, as well as Chuck, 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? I like that. And what are some good candidates aside from silicone?

Okay. Yeah, 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 the search needs to be conducted with the humility of the realization that we don't really know what we're looking for. We have some hunches about what's universal about life. And we know that carbon chemistry in water is a basis that can work. And we have good reason to believe that that could be functioning elsewhere because the conditions are available for it other places.

So it's a good thing to look for because we know it can work and we sort of know how to look for it. But 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 invented in a lab another kind of life that works as well.

But that could be because we're dumb, not because the universe doesn't know how to do it. No, we do it in our movies. Our movies, we do it 100 times over. Yeah, it happens in movies. And there is this move in NASA astrobiology to look for what we call agnostic biosignatures, which means trying to assume as little as possible

and looking for sort of more universal things that may not depend on carbon. But then you get into this question, what do we even mean by life? And what does life do? But you could talk about 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 using energy. And so we do have ideas about how to look for non-carbon-based life. And I think it's good to be reminded, so thank you for the reminder, that we should 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 for carbon in the molecule. And many 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 an attractive next option? Yeah, because in some ways, silicon 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 science classroom. And it's got, you know, on the upper left, it's got hydrogen. And 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 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 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 complex Lego set of molecules. Well, then it doesn't sound like 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. No. No, Chuck. No, black. I could be president. You know? No. No, Chuck. No, you can't. You cannot.

It is kind of like that. It depends on what features you're focusing on. Don't agree with Chuck on that. Don't egg him on. I'm sorry, Neil, but Chuck has a point here. It depends on what characteristics you're focusing on. You are under no obligation to agree with Chuck on this show. And the fact that silicon bonds to four of 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 carbon can get into all these weird configurations which make proteins and things. Silicon bonds tend to be really stiff and they don't make

those complex configurations the way carbon bonds do. For those who can't see, David Grinstone was just voguing in the last few moments. Shaping his hands around his face. Chemical voguing. Imitating the flexibility or rigidity of carbon and silicon bonds.

Strike a pose. Silicon. Silicon. Silicon likes to strike a pose and stick to it, yeah. Okay, gotcha. And so that's less flexible when life is experimenting on the diversity of what it may need to thrive in an environment. Yeah, and I don't think it makes, like, carbon makes polymers,

you know, the big molecules where it's not just carbon, but it's attached to lots of other things. Silicon makes, you know, the big molecules where it's not just carbon, but it's attached to lots of other things. Silicon 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. physical 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 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? 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 too 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's going to do the right thing to make life? The answer is no. But that may just, again, be a limit on our imagination. And as any good scientist, you got to sort of not only know your limits, but be prepared to shatter them as you take every next step going forward. Chuck, you got another question for Dr. Funky's Moon here? Yep, yep, yep.

This is Emily either Talas or Talias, one or the other, because there's a double L. So, hi, Chuck and Neil. Greetings from Paris, France. So maybe not either one of those in pronunciation. I know, you probably meant... Maybe not. Maybe not.

Okay. And then she goes, oh, look at this. Chuck, feel free to butcher my name. I can't wait to hear what you come up with. Oh! Oh, people setting you up. God.

That was good 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 less advanced than we are first how would 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? First of all, I love the question, and it's not one we think about very much because there's a set of assumptions 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 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. 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. We'll be right back after this first break.

Hey, I'm Roy Hill Percival, and I support StarTalk on Patreon. Bringing the universe down to earth, this is StarTalk with Neil deGrasse Tyson. We're back in StarTalk Cosmic Queries with David Grinspoon, a friend and colleague, and he's an expert on the solar system and astrobiology and all kinds of cool things such as that. David, how do we find you on social media? Well, I'm still on Twitter, at least today, and that's at DrFunkySpoon.

That's why we call you that, DrFunkySpoon. Yeah, and I'm on Facebook just under my name, and i'm on 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 f-u-n-k-y funky funky okay so all right i'm mastodon i'm hedging my bets okay so chuck we left off with a question about what would happen from from emily I'm Mastodon. I'm hedging my bets. Okay. So, Chuck, we left off with a question about what would happen. From Emily Talias. Well, she's from France. It was Emily?

Emily? That's right. Amelie. How do you Frenchify, Francophile Emily? So, she wants to know, what happens when we find life that's less intelligent than us? Right. That's hardly ever addressed in sci-fi storytelling. Yeah.

Because no one could imagine that we could be smarter than anything else in the universe. It's hardly ever addressed in sci-fi, but it's also hardly ever addressed 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 timescale, we're just babies, right? You know, four and a half billion years of earth, four billion years of life, depending on where you start it, a couple million years of being human and a few hundred years of being technological and less than a hundred years or a hundred years of being radio friendly. So we're babies. And 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, 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 and yeah and how would we find them because presumably then they wouldn't have traveled here so we have to stumble upon them or responded or responded so even even if they're not traveling here 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? It seems unlikely.

No, that would just be a tech level. That's not an intelligence level. No, that's a good point, too. Because you could argue there's always the whales, right? And the dolphins. They're really intelligent. They arguably have a civilization and a culture. I saw that Star Trek movie. The Save the Whales Star Trek movie.

Yeah, so we could certainly find intelligent life that is not technological at a level we are. And, you know, as far as protocols, it's pretty vague. You know, there are protocols for SETI. If we think we found something, a radio signal, what do you do? SETI, the Search for Extraterrestrial Intelligence, just the general term for that. Yeah. So 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 and some local interference. But then once you're sure, then the protocol is complete transparency. You alert everybody, you know. Unless the men in black get to you first yeah that's right right with a flashy thing yeah that yeah um so um you know and then if if somebody comes you know and lands a spaceship on earth uh and contacts us there's no real official protocol for that because it's not something that's just been,

you can argue whether it should be or shouldn't be, but it hasn't really been taken seriously enough by 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 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. That's all you need to do. I imagine that 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, with them among us. Yes, exactly. 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 basically props. We're props.

We're straight up props. Thank you, Chuck, for the happy thought there. I know. All right, here we go. By the way, I want to add something here. So, David, I just want to add that if we count chimps as sort of the next smartest species to us, just for the sake of this example,

we can't have a meaningful conversation with them. Think about it. And we've got 99% identical DNA. So 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 1% 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 beautiful? Yeah, your example of chimps really is an interesting one. And it kind of illustrates that something very recent has happened here on earth with humans that for better or worse, where we have these qualities of language and culture and so forth. And 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, 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 civilization, but also was less capable than us. Because it really illustrates that maybe we've just passed some kind of a 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 once you're over it,

then maybe you sort of can communicate even if you recognize that these guys are geniuses compared to us. It's an interesting question. Chuck, that's David's human ego that just got into that sentence. Yeah, we hit that threshold that we could communicate with any intelligent species smarter than us. I said maybe. Or maybe not. Maybe we're dumb as rocks compared to just about everybody in the universe. Thank you.

Thank you. I like that one. That's mine. That's the one I like. Chuck, keep them coming. All right. Thank you. I like that one. That's mine. That's the one I like. Chuck, keep them coming. All right. This is Sandra Pagliani. Sandra Pagliani says,

Good morning or evening, wonderful StarTalk 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. Yeah. That's good. Because a whole lot of other stuff you can think about that create anxiety and things. And if you can think about black holes on a plane and not feel anxious, that's good.

Yeah, I was going to say that we actually have an astrophysicist here, and it's not me. 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 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 to a black hole. We expect

those black holes to be pretty much rare, but everywhere, if you can picture that. 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 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 when there's another galaxy over here, 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. 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 to get a sense of it, a black hole, stellar black hole might be five, ten times the mass of the sun. But the supermassive 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. Do we see? No. Okay. Yeah, stars give out at about 60 to 100 times the mass of the sun. We don't find stars heavier than that. So we're not going to find a billion times

mass of the sun star. We just have never seen that. And so that's what we think something else is making them. That's something else. That is, wow, that is a wonderful mystery. Yeah, yeah. Well, the universe brims with mysteries. That's why David and I have a job.

And I love the fact that for the supermassive black hole, in our own galaxy, we can actually watch the stars orbiting it. And in a Nobel Prize winning observations, yes, 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 the distances, and you get a black hole. You get a black hole. Straight up. So cool. It's not a NASCAR track. No. It's a black hole.

That's very cool. All right. Here we go. 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? Ooh, I like that. Ha-ha.

I like that. Yeah. Yeah, David, we got these, you know, our atmosphere protects us from meteors. It protects us from UV light. It's, you know, so we're here

by the grace of the atmosphere. And so, if there's a planet out there, Earth-sized, Earth-gravity, Goldilocks zone maybe, and doesn't have these protectorates, I size, Earth gravity, Goldilocks zone maybe, and doesn't have these protectorates, I mean, these protecting forces? What do we do? Yeah, that's a great question.

I'm less worried about the magnetic field part, which is the other thing that the questioner asked, because we're learning more that makes us wonder how important magnetic fields are in protecting the surface of a planet. We used to say 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 one of my favorite planets, 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 solar wind itself sort of makes the upper atmosphere charged in such a way that it starts acting like it has a magnetic field. So, David, if memory serves, you wrote a book on Venus too. This is correct, yes. Wait, wait, sorry, you wrote a book on Earth about Venus. That's right. I was not on Venus when I wrote the book, but I wrote a book on the subject of Venus. So-

And the title of that book was what? That's Venus Revealed. Revealed, there you go. Yeah. Okay, good. You've been at this for a while. Yeah, yeah. So magnetic fields, I think life would find a way.

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 serves to transport, you know, think of Earth and the role of oxygen and carbon dioxide in plants and animal life, the transporting of chemicals that are involved 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. 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 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 energy transformations on the inside so that maybe you'd have internal life in the interior of the planet. 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 think of how you would

get a biosphere without an atmosphere. And there's nothing wrong with stretching the imagination. This is true. That's why we like these kinds of questions. Yeah, yeah, yeah. Chuck, we got to take a quick break. And David will be back in just a moment

for our third and final segment with David Funky Spoon Grinspoon on StarTalk. We're back. StarTalk. 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. It's self-based in Arizona, but he is distributed. 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. Always great to be here with you guys. So 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 Sharakan says,

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, to like look at stuff right in front of our noses. So who, when, what, in the dark of what night did that,

did that portfolio start? Who do you know that you were able to pull this off? When did that happen? Yeah. All right. Well, first of all,

Boston, my hometown, yay. Go Celtics. And the, it's wonderful what I think of that. As Neil implies, the web was not designed to look at exoplanets. It was designed for galaxies and other things like that, astrophysical targets. But 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 in a way, it's luck. It turns out web is sort of marginal for exoplanets, but there's so many good targets that we're starting to find them. And the exciting prospect now is that we can start to see what their atmospheres are made of. Even though, again, Webb 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 ideal, we're going to learn some really cool and important things about our planets in nearby star systems.

And that's just... So you're being opportunistic. Absolutely. That's a good thing. Absolutely, yes. All right, Chuck, keep it coming. All right, let's just keep going. That's a succinct answer, David, for 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 okay how many earth-like planets do we know about currently that reside in habitable orbits is there a number uh you know there, there's a lot of marginal ones. I would say a handful, you know, which is pretty good. Because when it comes to saying habitable orbits, some of them we're 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 good dozen or so that seem like pretty good candidates. Wait, David, there are 5,000 planets in the catalog right now. Are you telling me there's only like a dozen?

Well, I'm saying... Goldilocks planets? I'm saying ones that we... And it depends on what you mean by Earth-like. Okay? These are all gray area terms. But I'm saying roughly Earth-sized and definitely 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, 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 1%. that it's one out of 500. So that's still pretty low. That's like a fifth of 1%. Yeah, but a lot of those 5,000 are ones that will, could be. I'm giving a conservative number for ones that we can say, yes, that's earth-sized, and yes, that is really- So there's some in the running.

Absolutely. But it's still big news. It's still big news when we find one. That's why it's so exciting, this one that was just news when we find one. Yeah, that's why it's so exciting that, you know, 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 that people are still excited and aren't enough of them to get bored with it yet. Okay. Chuck, keep it coming. All righty, here we go. This is Zeki Mased, I think.

I mean, maybe. You're the reader here, so it's always what you think. Zeki Mazed. Okay, you're right. Exactly. Yeah. I'm going to tell you the truth. I really don't think that, but that's about as close as I can come.

Okay. He says, Hey, Neil. Hey, David and Seth McFarlane's The Orville 25th Century Life has progressed far into the galaxy, solved 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. I would say in three sentences, yes, I think it's possible, though not assured.

And that the path is not going to be smooth between here and there and that the key is some sort of a globally enlightened society where we guide ourselves with the recognition that we are one planetary species despite all of our wonderful differences. Just as a guiding force operating on our future decisions. Right. Well, there you go. Here's your answer. We're screwed. And I think 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 someone developed a replicator where 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. It's post-scarcity. Correct. A post-scarcity world 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 rest but one

of them is you don't need money it's interesting because money is just a belief system any anyways we all fool ourselves into thinking it has value so it does have value so we can always change our minds collectively about that right right right 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 okay but then how do you explain Ferengis? Well, yeah, they're greedy little bastards. That's how you explain them. They're just greedy little bastards.

They don't care. They have it all and they still want more. But Chuck, what you said is deep because what it would do, it would liberate the creativity of every citizen of the world to 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 to. Right, because, yeah, yeah, exactly. Deep. I like it. I think we should just, like, start that world right now. What are we waiting for? No, no. Oh, that's great.

And on January 17 17th 2023 a revolution took hold spread like wildfire across the base 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 do these planets need to be to Earth to look for these aspects in the planet's climate? I like that. Yeah. Yeah, so 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 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 that's the number one thing. There's enough greenhouse gases, carbon dioxide. In a good way. Yeah, exactly.

In a good way. 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's the sort of prime directive, if you will, for habitability. And what was the second part of the question? What do we look for to... Oh, how far away, how far away. How far away. Again, with the tools we have now,

it's very difficult to 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 if we, as we get better instruments that we want to build in the future, we'll be able to greatly expand the number of than if you're thousands of light years. But as we get better instruments that we want to build in the future,

we'll be able to greatly expand the number of planets we can do that for. 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? Yes. No, they never were. Because at some point, Spock would say, oxygen, nitrogen, atmospheres, Captain. And so then they'd go down and they'd just breathe it. It's a class M planet, Captain. 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, correct me if I'm wrong here, if it has oxygen, something's making the oxygen. 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, there's active stuff going on there. Yeah, the reason why we have

a breathable atmosphere is because there's life here. And so any planet you find with that kind of atmosphere would be very surprising. Like you say, Neil, 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. So cool. Okay, a couple more. Chuck, man, we're blowing through these. Very nice. All right. Yes, we are. Yes, we are.

Here we are. Now, we got to speed up even more. So, David, soundbite mode. Okay. Remember, so ABC News just put a microphone in front of your lips, and they're going to soundbite you for the evening news. So here it is. Go, Chuck.

All right. Hello, Chuck. Hello, Neil. Hello, Dr. Funky Spoon. Okay, here we go. Does weed still work in space, or are the THC crystals too fragile for space? What temperature, what hemp crop would be 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 is... You told me 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 have to smoke it. We have gummies. Exactly. And tell me about the soils of Mars. Can you grow anything there? Yeah. I mean, if you could grow 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.

Okay. The soil by itself as of now probably isn't very fertile, you know, because it doesn't have organics. As we learned from the book and movie, The Martian. Yeah. But it could certainly... He had poop. You could certainly mix in a little either human-generated

or otherwise-generated fertilizer and grow stuff on Mars. Human-generated fertilizer and grow stuff on Mars. Human-generated fertilizer. Fertilizer. Right on. Yeah. I always knew you were full of fertilizer. We call that HGF. Nice.

Nice. One last one, Chuck. That's all we got time for. Here we go. This is Akshat Oh, Chuck. That's all we got time for. Here we go. This is Akshat. Oh, man. Why does it take you as long to read the name as the question itself?

Because I don't prepare. Okay. Pathikar. That's it. Askat Pathikar, who says this 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 yes what does the climate history have to say about the evolution of the entire planet?

Thanks, and I love the show. Oh, and this is from India. Just want to give a shout out. This is from India. India has been 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 that's going to be. That may be where that came from. Very good.

Okay. So, welcome to the company of space-faring nations, I say to the nation of India. 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 and lost them, but we want to gather the evidence to be sure of that. 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.

Wait, wait, you said you don't talk about it. That implies you don't talk about it in public. No, no, no. You heard how he said that, Chuck. We don't talk about that. I did. We don't talk about that. No, I just mean this.

We don't talk about that. That's not amongst our... Like Bruno in the Disney movie. We don't talk about Bruno. We don't talk about that. I did. We don't talk about that. No, I just mean this. We don't talk about that. That's not amongst our... Like Bruno in the Disney movie. We don't talk about Bruno. I meant that's not amongst our most favored hypotheses, but it's certainly not that thing we could rule out. Thanks for letting me clarify that. Yes, thank you very much there.

But clearly, Venus does have a runaway greenhouse effect, and they're just worried. Maybe Venus has knobs that got turned right 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. You got it. Now, is runaway greenhouse effect

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, not that we make that it is going to happen, but is it possible here? 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. I got you. But in the future, as the sun warms up, which it is slowly, in a billion years or so, 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 from now. A billion years. Always, yes. That's some serious-ass future that we're talking about.

Exactly. We have more immediate problems, but nonetheless, it's still interesting to picture that long-term future. Let me add something and get David's blessing on this comment before we close it out. So, David, in all my readings on this, I agree that if you extracted

all fossil fuels and burned them all with none left, Earth would be hotter, but you would not have the runaway greenhouse effect experienced by Venus. What you would need to do is somehow dissolve all of the world's limestone and other repositories of carbon that's beyond just fossil fuels or fossils, right? 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 fair? Yeah, I think that's right. Because then, I mean, Venus has sort of like 100 bars almost of CO2, which is 100 times the atmospheric thickness of Earth. If you burned all of 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 try this, mind you. Don't try this at home. Then I think you probably could turn Earth into Venus.

Yeah, okay. All right, so we're not doing that for sure. But anyhow. But the one thing we know for certain is that greenhouse effect is from carbon in the atmosphere. That is just the way it is. Carbon dioxide. Carbon dioxide. Yes. 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. Absolutely. Absolutely. We're going in that direction, and it's the wrong direction for us.

Okay. There you go. For our survival. Yes. All right. We got to call it quits there on that down note. I was going to say, Chuck, I had a good high note. Kiss your kids goodnight note a couple of minutes ago

and then you had to just take it down. All right. A few minutes ago, we were abolishing all money and liberating human creativity. We saved humanity in the last question. And then, of course, we destroyed it with this one. Those are the

breaks. This is StarTalk Cosmic Queries, one of the breaks. This is StarTalk Cosmic Queries, one of our favorite variants on the StarTalk 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, I bid you to keep looking up.