Speaker 1: Welcome to stuff to Blow your mind from how Stuff
Speaker 1: Works dot com. Hey you welcome to Stuff of all
Speaker 1: your mind. My name is Robert Lamb and I'm Julie Douglas.
Speaker 1: And you know, when you look at space explorestion, you
Speaker 1: know we're looking outward, but then there's also a lot
Speaker 1: of looking inward. Um. It's just about anything humans do.
Speaker 1: You can sort of make a case for the selfishness
Speaker 1: of it and the self absorption of it. So we
Speaker 1: look out into space because we want to know something
Speaker 1: about ourselves. A lot of the times we want to
Speaker 1: know what's out there because we want to know where
Speaker 1: we fit in. We want to know if there's intelligent
Speaker 1: life or life out there at all, because that puts
Speaker 1: who we are and what we are in some level
Speaker 1: of perspective. And that's one area where set comes into play,
Speaker 1: the search for extraterrestrial intelligence. Right, So, as long as
Speaker 1: there have been humans, um, there has been this question
Speaker 1: of are we alone in the universe? Because you can't
Speaker 1: help but look up in the night sky and say,
Speaker 1: is that it? You know? Is there? Are we unique?
Speaker 1: There are all sorts of questions that roll out here. Now.
Speaker 1: Of course, astrophysicists astrobiologists, um, astronomers are all trying to
Speaker 1: answer this question, and they're looking more though, in the
Speaker 1: infancy infancy of really this possibility of intelligent life. And
Speaker 1: when I say infancy, I'm talking more about Mars and
Speaker 1: the possibility of microbial life there, or Jupiter's moon Europa
Speaker 1: and the presence of water underneath the frozen oceans, or
Speaker 1: liquid hydrocarbon lakes on Saturdays moon Titan. So we have
Speaker 1: to look there first because we know that those are
Speaker 1: sort of the building blocks of microbial life, which then
Speaker 1: evolves into something more significant or complex, I should say. So,
Speaker 1: of course this leads to this question of well, are
Speaker 1: we really unique? Um? Is life the flora and fauna
Speaker 1: on Earth unique to us? Is that it? Um? And
Speaker 1: this is a huge question and we have to unpack
Speaker 1: it a little bit. Yeah. I mean, as we've discussed before,
Speaker 1: when when you're talking about life, I mean, ultimately we
Speaker 1: have the one model to go on. So we inevitably
Speaker 1: we keep coming back to that, what is life and
Speaker 1: so stuff on this planet? What are the parameters for
Speaker 1: life as we have seen it so far as we
Speaker 1: know it? And uh, and what are what's the chemical
Speaker 1: formula for what is required, what elements? When do we
Speaker 1: need to look for? It's uh, I often think about it.
Speaker 1: It's kind of like um, shopping for a new house.
Speaker 1: You know, you're looking at all right now, what what's
Speaker 1: what kind of neighborhood do I want to live in? What? What?
Speaker 1: What do I need to be close enough to? What
Speaker 1: resources need to be nearby to make it agreeable? What?
Speaker 1: What type of neighborhood is is too hostile to me? Uh?
Speaker 1: You know, like one one area is going to be
Speaker 1: too fancy, too too rich, just excluding completely another area, uh,
Speaker 1: might be a war zone. You know. We have to
Speaker 1: say to take all of this into into account even
Speaker 1: when we're looking for extratrustrial life, because we're looking at
Speaker 1: where where else could life exist more or less like
Speaker 1: it exists here, You're right, So we really have to
Speaker 1: turn to ourselves. And we know that the chemical composition
Speaker 1: of earth face life consists of hydrogen, carbon, and oxygen.
Speaker 1: So that accounts for more than of the atoms and
Speaker 1: the human body and in all other known life. So
Speaker 1: of those three, carbon is really the star of the show,
Speaker 1: since it can bond with itself and other molecules really easily,
Speaker 1: and it's a very strong bond. Now, if you kind
Speaker 1: of take the lens here from from humans and um
Speaker 1: and another life on Earth, and you sort of go
Speaker 1: out a little bit into the universe, what do you find?
Speaker 1: You find the most common elements in the universe are hydrogen, helium, carbon,
Speaker 1: and oxygen. Okay, So what is this saying. This is
Speaker 1: saying that, uh, life is not chemically special, especially if
Speaker 1: you consider that the basis of it can be easily
Speaker 1: found in the universe and then harnessed here on Earth.
Speaker 1: And if life on Earth were composed primarily of manganese
Speaker 1: or molly bendum, then we would have excellent reason to
Speaker 1: suspect that we're something special in the universe. But it's not. Yeah,
Speaker 1: all this stuff is everywhere. It's kind of you know,
Speaker 1: it's kind of like you know when you you're a
Speaker 1: certain age and you find this book that you really
Speaker 1: dig and you're like, oh, my goodness, is it the
Speaker 1: most n album? Say it's an album by a group,
Speaker 1: and you're like, how this is the most precious thing? This?
Speaker 1: I love this, this album in this book so much.
Speaker 1: It speaks directly to me. The artist is speaking directly
Speaker 1: to me, and only I can really appreciate it in
Speaker 1: the way that I'm appreciating it now. And then you realize, oh,
Speaker 1: it's a nation nationwide bestseller, or it's it's on the
Speaker 1: top ten Billboard charts, or you know, the went triple
Speaker 1: platinum or whatever, and you realize, oh, actually, this appeals
Speaker 1: to a lot of people, and I am not special
Speaker 1: in liking it. Yeah, and you discover that it's playing
Speaker 1: throughout the universe, right, the same music, and it's the
Speaker 1: same elements, those same ingredients that make us that are
Speaker 1: out there in the stars. But we've talked about this before,
Speaker 1: because you've talked about if his start implodes um, you know,
Speaker 1: it's throwing out all sorts of material into the universe.
Speaker 1: And you know, there's that the great quote by Lawrence
Speaker 1: Cross says, you know the atoms in your right hand
Speaker 1: are in your left hand all came from that one
Speaker 1: star exploding. So it makes sense. This is this is
Speaker 1: the stuff that's making that soup. This is the base
Speaker 1: of the soup. Um. And if you take that logic,
Speaker 1: then you start to say, Okay, it's not unique. This
Speaker 1: is a recipe that could be executed elsewhere on the universe. Yes,
Speaker 1: But of course the thing about recipes. Um, so we
Speaker 1: all know is that it's it's not merely enough to
Speaker 1: know what goes in, but you have to know, uh
Speaker 1: what amounts going You need to know is it is
Speaker 1: it a tablespoon of salt or a teaspoon of salt?
Speaker 1: Um makes the world of difference. Um, are certain substitutions allowed,
Speaker 1: which ones are not? How are you heating it? How
Speaker 1: are you preparing it to make all the difference in
Speaker 1: in the ultimate outcome of the recipe? And likewise there
Speaker 1: is a lot of that to take into account, just
Speaker 1: chemically with with Earth and life on Earth. In his
Speaker 1: book The Autographs, Diyson points out the oxygen thing. You
Speaker 1: need a lot of free oxygen and that needs to
Speaker 1: be supported by some sort of a system on our
Speaker 1: planet's ported of course, by all the vegetation that we
Speaker 1: we have on this planet. So you have to have
Speaker 1: the right circumstances in place to allow the right chemical
Speaker 1: situation to be in order. So evolution is kind of
Speaker 1: like the baking time, right. So if it takes ten
Speaker 1: billion years for a planet become hospitable, then that's ten
Speaker 1: billion years of baking time. And so you have to
Speaker 1: consider that when when we're talking about exo planets, and
Speaker 1: we're talking about them being just the right distance from
Speaker 1: the star or um from a sent or a moon
Speaker 1: to have the correct elements there for the baking. Right,
Speaker 1: that's just one aspect of it. But again, the ingredients
Speaker 1: for the recipe your out there, which makes it so
Speaker 1: tantalizing of a question of whether or not there exists
Speaker 1: other life and intelligent life at that UM. Of course,
Speaker 1: we had to go back to something called the Copernican principle,
Speaker 1: uh to really sort of understand how life may not
Speaker 1: be that special in the first place. Yeah. And then this,
Speaker 1: of course kind from should say chemical life. Yes, this
Speaker 1: of course comes to us from a mid Polish astronomer,
Speaker 1: Nicolas Copernicus. Um and uh. And basically the whole deal
Speaker 1: here is that we're nothing special, and that you cannot
Speaker 1: enter a scientific analysis of the universe with the idea
Speaker 1: that we're something special. There are a number of different
Speaker 1: things that spin off of this, For instance, UM. In
Speaker 1: nineteen seventy four, astronomer Brandon Carter tackled the quandary of
Speaker 1: our anti anthropic coincidence, the idea that there are a
Speaker 1: number of coincidences that supposedly make life on Earth possible UM,
Speaker 1: and he hypothesized that these coincidence are part of the
Speaker 1: universe very structure, and the chance has nothing to do
Speaker 1: with it. He proposed two variants, the most important what
Speaker 1: we're talking about here is the strong anthropic principle UH.
Speaker 1: And in this he drew on the Copernican principle UH,
Speaker 1: which again states that there's nothing special or privileged about
Speaker 1: Earth or humanity. Uh. We live in a universe capable
Speaker 1: of supporting life than than only life supporting universes are possible.
Speaker 1: You can really go down the rabbit hole with this,
Speaker 1: But essentially it's about putting aside any idea that we
Speaker 1: are special. Again, the the the album is a hit
Speaker 1: around the universe that the building blocks are out there. Uh.
Speaker 1: We can't enter into any kind of an analysis of
Speaker 1: or even of a pondering of life else where in
Speaker 1: the universe if we're thinking that we're special in some way. Yeah.
Speaker 1: And what I really like about the comparonic in principle
Speaker 1: is that it does show an evolution of understanding of
Speaker 1: our place in the universe, because you know, Comparnicas of
Speaker 1: sitting there saying at a time where everybody was thinking
Speaker 1: the opposite is saying, hey, the Earth is not the
Speaker 1: center of our solar system. And so, of course that
Speaker 1: was a crazy thought at the time. Yeah, because for
Speaker 1: the longest, Yeah, Earth has to be the center. We're
Speaker 1: the center God's blessed creation. So we should be right
Speaker 1: there at the center. How can this whole thing not
Speaker 1: be about us? Right? We are it right? Um. But
Speaker 1: then there's this idea that evolves even more like, okay, hey,
Speaker 1: well we're not the center of the Solar system in
Speaker 1: the Milky Way, by the way, our Milky Way, our
Speaker 1: galaxy is not the center of universe. In fact, we're
Speaker 1: not quite sure what the center is. Is there a center? Um?
Speaker 1: So you really do see this, This understanding become much
Speaker 1: more complex and nuanced as we get more and more
Speaker 1: data from the world around us, because now we understand
Speaker 1: that Earth is just one of billions of planets that
Speaker 1: are all bathing in the same sort of primary chemicals. Um.
Speaker 1: So that gets us to this area called the Drake equation.
Speaker 1: So we really have to talk about this before we
Speaker 1: can even sort of say, okay, we'll do aliens exist,
Speaker 1: How would they exist? How would we contact them? All? Right,
Speaker 1: We're gonna take a quick break and when we come
Speaker 1: back even more on the search for extraterrestrial intelligence. Yes,
Speaker 1: the Drake equation. So the Drake equation is pretty widely known.
Speaker 1: It's been spun off into a number of interesting little
Speaker 1: side projects, like there was a there's a really good
Speaker 1: episode of This American Life where that's a team of
Speaker 1: scientists try to use the Drake equation to determine whether
Speaker 1: they have a true love match out there in the
Speaker 1: world waiting for them, as opposed to is there another
Speaker 1: life form or other life forms elsewhere in the galaxy. Yeah,
Speaker 1: because I want to say this just at the front here,
Speaker 1: that the Drake equation is not something that is solvable.
Speaker 1: It is it's really about probabilities and how to organize
Speaker 1: our thoughts about the data that we have in the
Speaker 1: missing data. Yeah, it's about taking the one big question,
Speaker 1: the one big probability is their life else from in
Speaker 1: the universe, and breaking it down into smaller questions, smaller
Speaker 1: probabilities that we can tackle individually. So the entire equation
Speaker 1: looks like this, and and this is not gonna all
Speaker 1: make a lot of sense, but just in the in
Speaker 1: the in the interest of getting out there, it is
Speaker 1: in equals our star multiplied by F sub p multiplied
Speaker 1: by in sub multiplied by F sub F sub l
Speaker 1: multiplied by F sub i multiplied by F subc multiplied
Speaker 1: by capital l. And so all those numbers must by
Speaker 1: together help us to estimate the number in of technical
Speaker 1: logical civilizations that might be able to detect us right now. Now,
Speaker 1: if you guys all bear with me, let me unpack
Speaker 1: that a little bit, because I do think it's interesting.
Speaker 1: Um our star is the rate at which stars have
Speaker 1: been born in the Milky Way galaxy over the last
Speaker 1: few billion years. That stars per year, okay, And then
Speaker 1: all the f factors in this are fractions. So F
Speaker 1: sub p is a fraction of stars that have planets,
Speaker 1: and sub e is the average number of habitable planets
Speaker 1: in any planetary system. F sub l is the fraction
Speaker 1: of planets on which life actually begins. F sub i
Speaker 1: is a fraction of all those life forms that develop intelligency.
Speaker 1: How this becomes Tinier and jiner um. And then F
Speaker 1: sub c is the fraction of intelligent life that develop
Speaker 1: a civilization that uses some sort of transmitting technology. Finally, L,
Speaker 1: which is really important here, and we'll talk more about
Speaker 1: this later l is the longevity factor. On average, how
Speaker 1: many years do those transmitters continue to operate, because, as
Speaker 1: we know, civilizations come and go. Yeah, Like I kind
Speaker 1: of like to think of it in terms of a
Speaker 1: video store, like you know, and some of you may ask,
Speaker 1: what what what is that? Because they are starting to
Speaker 1: disappear more and more. But like in the Atlanta we
Speaker 1: have this really cool video store called Video Drome. I
Speaker 1: still like to go there just to brows around for
Speaker 1: nostalgia and nothing else. But you know, I walk into
Speaker 1: a video store and I have, you know, X number
Speaker 1: of videos at my disposal for possible rent. But then
Speaker 1: you have to you have to carve that down all right,
Speaker 1: of all the videos here, I can only check out
Speaker 1: ones that are checked in, so that dude decreases the number.
Speaker 1: Then maybe I'm only interested in seeing an English language
Speaker 1: film because I don't want to read subtitles tonight, So
Speaker 1: then we have to cut that down. Then I must
Speaker 1: say I'm only interested in seeing a horror movie, so
Speaker 1: that cuts it down even more. And then I only
Speaker 1: interested in seeing a horror movie that I haven't already seen,
Speaker 1: so that cuts it down even more. And again you
Speaker 1: just get down to there are x number of films
Speaker 1: that I could potentially rent this evening. Now, what I
Speaker 1: think is cool about this dract equation is that, yes,
Speaker 1: there's no righting answer right now, and this is just
Speaker 1: a way of organizing information because a lot of it
Speaker 1: does depend on who's plugging in the data and why
Speaker 1: right in the same way that my data I plug
Speaker 1: into this video drum equation could be different one day
Speaker 1: from the next. The deal is, though, is that astronomers
Speaker 1: are actually getting at this equation right. They've already tried
Speaker 1: to figure out about three of those different fractions, So
Speaker 1: they're trying to figure out the fraction of stars planets,
Speaker 1: the average number of habitable planets, and the fraction of
Speaker 1: planets on which life actually begins. So they're getting to that.
Speaker 1: So when I talk about exit planets that are habitable
Speaker 1: and that goldilocks not too hot, not too cold, that'
Speaker 1: from one aspect of it that they're beginning to collect
Speaker 1: data on um and they're beginning to say like, okay, well,
Speaker 1: now we can get these chemical signatures and try to
Speaker 1: figure out, you know, how much carbon is being produced there,
Speaker 1: how much method sane which you know something we'll talk
Speaker 1: more about as pretty plentiful here on Earth, and that's
Speaker 1: a that's a huge signal if there's something going on
Speaker 1: on that planet, right probably probably cows as well as
Speaker 1: other you know, factors that that create methane that I
Speaker 1: won't go into. Uh, But anyway, my point is is
Speaker 1: that yes, this is, uh, this is somewhat of a
Speaker 1: thought experiment, but astronomers are scratching away at it and
Speaker 1: they're getting some concrete information in there. Yeah. Um, I
Speaker 1: mean historically whether the estimate the results have varied again
Speaker 1: depending on what's going into it, and they varied from
Speaker 1: there being one one but one civilization out there two millions.
Speaker 1: So yeah, right, Again, there's a lot of data that
Speaker 1: needs to be plugged in here, but astronomers are if
Speaker 1: if you will, plugging away at that. Now, I wanted
Speaker 1: to mention the Fermi paradox, and this is something I
Speaker 1: want you guys to all put in your back pocket
Speaker 1: as you consider all the other information that we talked
Speaker 1: about today. The Fermi paradox is from the Noble Prize
Speaker 1: winning physicist and Rico Fantom and he reasoned that if
Speaker 1: it takes life billions of years, should develop intelligence and
Speaker 1: signal or travel to the stars. And if there are
Speaker 1: billions of worlds in the universe, and if the universe
Speaker 1: is over thirteen billion years old, then why haven't we
Speaker 1: been visited by an extra terrestrial or why isn't the
Speaker 1: galaxy crawling with extraterrestrials. This is something we'll get too later.
Speaker 1: But that's that's a good question, right, yeah, I mean
Speaker 1: it's Stephen Hawking brought up the same thing with time travel.
Speaker 1: You have if time travel was possible, is possible, will
Speaker 1: be possible? When I have we not been visited by
Speaker 1: a time traveler. Like it's just kind of a basic,
Speaker 1: you know, show me level of of of analysis. Okay,
Speaker 1: they're aliens, great, show me one, show me the alien
Speaker 1: put it on the table for me to see because
Speaker 1: the time traveler erased our memory, and certainly you could,
Speaker 1: you can, you can roll out varying levels of conspiracy
Speaker 1: and and explanations on top of it. But you know,
Speaker 1: at the at the very root, it's it's a question
Speaker 1: of all right, if they're aliens, then we should have
Speaker 1: seen them, We should see them, and then you can
Speaker 1: you can apply your own excuses as to why don't
Speaker 1: we have not Alright, Well, On that note, we're going
Speaker 1: to actually call this an episode. We're splitting the SETI
Speaker 1: episode up into two episodes, so this was part one.
Speaker 1: Part two will publish very shortly, so be on the
Speaker 1: lookout for that in the time being. If you have
Speaker 1: any kind of feedback on part one, you can find
Speaker 1: us on Facebook and you can find us on tumbler.
Speaker 1: We are stuff to blow your mind on both of
Speaker 1: those and we use the handle blow the Mind on Twitter,
Speaker 1: and you can always drop us a line at below
Speaker 1: the Mind at Discovery dot com. For more on this
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