SETI: The Search for Extraterrestrial Intelligence, Part 1


Is there life out there in the cosmos and if so how do we find it? How might it find us? In this episode of Stuff to Blow Your Mind, Julie and Robert discuss the history of SETI as well as what classic TV shows our alien neighbors might be listening to.

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Welcome to Stuff to Blow Your Mind from

Robert: Hey, welcome to Stuff to Blow Your Mind, my name is Robert Lamb.

Julie: And I'm Julie Douglas.

Robert: And when you look at space [inaudible], we're looking outward, but then there's also a lot of looking inward. Just about anything humans do you can sort of make a case for selfishness or it and the self-absorption of it. So we look out into space because we want to know something about ourselves a lot of the times. We want to know what's out there because we want to know where we fit in.

We want to know there's intelligent life or life out there at all because that puts who we are and what we are in some level of perspective, and that's one area where seti comes into place, the search for extraterrestrial intelligence.

Julie: Right, and so long as there have been humans there has been this question of are we alone in the universe because you can't help but look up into the night sky and say is that it. Are we unique? There are all sorts of questions that roll out here. Now of course astrophysicists, astrobiologists, astronomers are all trying to answer this question and they're looking more though in the infancy of really this possibility of intelligent life and when I say infancy, I'm talking more about Mars and the possibility of microbial life there or Jupiter's moon, Uropa and the presence of water underneath the frozen oceans or liquid hydrocarbon lakes on Saturn's moon, Titan.

So we have to look there first because we know that those are sort of the building blocks of microbial life, which then evolves into something more significant or complex I should say. So of course this leads to this question of well are we really unique. Is the life the flora and fauna on earth unique to us, is that it? And this is a huge question, and we have to unpack it a little bit.

Robert: Yeah, I mean as we've discussed before when you're talking about life. I mean ultimately we have the one model to go on, so inevitably we keep coming back to that. What is life [inaudible] on this planet? What are the parameters for life as we have seen it so far, as we know it, and what's the chemical formula for it? What is required? What elements do we need to look for? It's - I often think it's kind of like shopping for a new house. You're looking all right, now what kind of neighborhood do I want to live in? What do I need to be close enough to? What resources need to be near by to make it agreeable? What type of neighborhood is too hostile to me, like one area is gonna be too fancy, too rich, just exclude me completely.

Another area might be a war zone. We have to take all this into account even when we're looking for extraterrestrial life because we're looking at where else could life exist more or less like it exists here.

Julie: You're right, so you're really having to turn to ourselves, and we know that the chemical composition of earth base life consists of hydrogen, carbon and oxygen, so that accounts for more than 95% of the atoms in the human body in all other known life. So of those three carbons is really the star of the show since it can bond with itself and other molecules really easily and it's a very strong bond.

Now if you kind of take the lenses here from humans and other life on earth, and you sort of go out a little bit into the universe what do you find, you find the most common elements in the universe are hydrogen, helium, carbon and oxygen. So what is it saying, this is saying that life is not chemically special, especially if you consider the basis of it can it be easily found in the universe, and then harnessed here on earth. And is life on earth composed primarily of manganese or molybdenum then we would have excellent reason to suspect that we're something special in the universe, but it's not.

Robert: Yeah, all this stuff is everywhere. It's kind of like when you're at a certain age and you find this book that you really dig, and you're like oh my goodness, this is the most - or an album. Say its an album by a group and you're like oh, this is the most precious thing. I love this album or this book so much it speaks directly to me, the artist is speaking directly to me and only I can really appreciate it in the way that I'm appreciating it now. And then you realize oh, it's a nationwide bestseller or if it's on the Top 10 Billboard charts or it went triple platinum or whatever, and your realize oh, actually this appeals to a lot of people and I am not special in liking it.

Julie: Yeah, and you discover that it's playing throughout the universe right, the same music and its that same elements, the same ingredients that make us that are out there in the stars. We've talked about this before because you've talked about it implodes it's throwing out all sorts of material into the universe. There's the great quote by Lawrence Krause that says "you know the atoms in your right hand, in your left hand all came from that one star exploding", so it makes sense. This is the stuff that's making that soup, this is the base of the soup. If you take that logic, then you start to say okay, it's not unique. This is a recipe that could be executed elsewhere on the universe.

Robert: Yes, but of course the thing about recipes, as we all know, is that it's not merely enough to know what goes in, but you have to know what amounts go in. You need to know is it a tablespoon of salt or a teaspoon of salt, it makes the world of difference. Are certain substitutions allowed and which ones are not? How are you heating it, how are you preparing it? It makes all the difference in the ultimate outcome of the recipe and likewise. There is a lot of that taken into account just chemically with earth and life on earth.

In his book [inaudible] Dyson points out the oxygen thing, you need a lot of free oxygen, and that needs to be supported by some sort of system on our planet to support it of course by all of the vegetation that we have on this planet. So you have to have the right circumstances in place to allow the right chemical situation to be in order.

Julie: Yeah, so evolution is kind of like the baking time right?

Robert: Yeah.

Julie: So if it takes ten billion years for a planet to become hospitable then that's 10 million years of baking time, and so you have to consider that when we're talking about XO planets and we're talking about them being just the right distance from the star or from a center or moon to have the correct elements there for the baking right, that's just one aspect of it. But again, the ingredients for the recipe are out there, which makes it so tantalizing of a question of whether or not there exists other life, and intelligent life at that. Of course we had to go back to something called the Copernican Principal to really sort of understand how life may not be that special in the first place.

Robert: Yeah, and this of course comes from -

Julie: I should say chemical life.

Robert: Yes. This of course comes to us from a mid-1500 Polish Astronomer Nicholas Copernicus, and basically the whole deal here is that we are nothing special, and that you cannot enter a scientific analysis of the universe with the idea that we're something special. There are a number of different things that spin off of this. For instance, in 1974 Astronomer Brandon Carter tackled the quandary of our anthropic coincidence, the idea that there are a number of coincidences that supposedly make life on earth possible.

He apotheosized that these coincidences are part of the universal structure, and the chance is nothing to do with it. He proposed two variants, the most important what we're talking about here is the strong anthropic principle, and in this he drew on the Copernican principle, which again states that there's nothing special, privileged about earth or humanity. We live in a universe capable of supporting life than only life supporting universes are possible. You can really go down the rabbit hole with this, but essentially it's about putting aside any idea that we are special.

Again, the album is a hit around the universe that the building blocks are out there, we can't enter into any kind of analysis or even the pondering of life elsewhere in the universe if we're thinking that we're special in some way.

Julie: Yeah, and what I really like about the Copernican principle is that it does show an evolution of understanding of our place in the universe because Copernicus is sitting there saying at a time where everybody was thinking the opposite is saying hey, the earth is not the center of our solar system. And so of course that was a crazy thought at the time.

Robert: Yeah, because for the longest yeah, earth has to be the center. We're the center.

Julie: We're the center right?

Robert: We're God's blessed creations, so we should be right there at the center. How can this whole thing not be about us?

Julie: Right, we are it right? But then there's this idea that evolves even more like okay, hey well, if we're not the center of the solar system and the Milky Way, by the way our Milky Way, our galaxy is not the center of the universe. In fact, we're not even quite sure what the center is, is there a center. So you really do see this understanding become much more complex and nuanced as we get more and more data from the world around us because now we understand that earth is just one of billions of planets that are all bathing in this same sort of primary chemicals.

So that gets us to this area called the Drake Equation. So we really have to talk about this before we can even sort of say okay, do aliens exist, how would they exist, how would we contact them.

Robert: All right, we're gonna take a quick break and when we come back even more on the search for extraterrestrial intelligence. Julie, a quick trip to the post office is almost never quick because you've got to drive there, you've got to find parking, anyone should get inside it's still a hassle, so everyone should really do what we do, and that is you should use instead.

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Yes, the Drake Equation. So the Drake Equation is pretty widely known. It's been spin off a known number of interesting little side projects, like there's a really good episode of This American Life where a Latino scientist tried to use the Drake Equation to determine whether they have a true love match out there in the world waiting for them as opposed to is there another life form or other life forms elsewhere in the galaxy.

Julie: Yeah, because I want to say this, just at the front here that the Drake Equation is not something that is solvable, it's really about probabilities and how to organize our thoughts about the data that we have and the missing data that we have.

Robert: Yes, it's about taking the one big question, the one big probability is there life elsewhere in the universe and breaking it down into smaller questions, smaller probabilities that we can tackle individually. So the entire equation looks like this, and this is not gonna all make a lot of sense, but just in the interest of getting it out there. It is N equals R Star multiplied by F sub P, multiplied by N sub E, multiplied by F sub L, multiplied by F sub I, multiplied by F sub C, multiplied by L. So all those numbers multiplied together help us to estimate the number N of technical, logical, civilizations that might be able to detect us right now.

Julie: Now, if you guys all bare with me, let me unpack that a little bit because I do think its interesting. R Star is the rate at which stars have been born in the Milky Way galaxy over the last few billion years, that's stars per year okay. And then all the F factors in this earth fraction, so F sub P is a fraction of stars that help planets, N sub E is the average number of habitable planets in any planetary system. F sub L is the fraction of planets on which life actually begins. F sub I is the fraction of all those life forms that develop intelligences as it becomes tinier and tinier, and then F sub C is the fraction of intelligence life that develop a civilization that uses some sort of transmitting technology.

Finally L, which is really important here, and we'll talk more about this later. L is the longevity factor on average how many years do those transmitters continue to operate. As we know civilizations come and go.

Robert: Yeah, I kind of like to think of it in terms of a video store, like some of you may ask what is that because they're starting to disappear more and more, but like in Atlanta we have this really cool video store called Video Drone, I still like to go there just to browse around for nostalgia if nothing else. But I walk into a video store and I have X-number of videos at my disposal for possible rent, but then you have to carve that down. All right, of all the videos here I can only check out ones that are checked in, so that does decreases the number. I can then - maybe I'm only interested in seeing an English language film because I don't want to read subtitles tonight, so then we have to cut that down.

Then I'm only interested in seeing a horror movie, so that cuts it down even more. And then I'm only interested in seeing a horror movie that I haven't already seen, so that cuts it down even more and again, you just get down to there are X-number of films that I could potentially rent this evening.

Julie: Now what I think is cool about the Drake Equation is that yes, there's no right answer right now, and this is just a way of organizing information.

Robert: Because a lot of it does depend on who's plugging in the data and why, and the same way the data I plug into this Video Drone equation could be different one day from the next.

Julie: The deal is though is that astronomers are actually getting at this equation right? They've already tried to figure out about three of those different fractions, so they're trying to figure out the fraction of stars that have planets, the average number of habitable planets and the fraction of planets on which life actually begins. So they're getting to that, so when I talk about XO planets that are habitable and Goldilocks zone, not too hot, not too cold, that's one aspect of it that they're beginning to collect data on.

And they're beginning to say like okay, now we can get these chemicals signatures and try to figure out how much carbon is being produced there, how much methane, which something we'll talk more about is pretty plentiful here on earth, and that's a huge signal that there's something going on, on that planet right?

Robert: Yes, probably cows.

Julie: Probably cows as well as other factors that create methane that I won't go into. But anyway, my point is that yes, this is somewhat of a thought experiment, but astronomers are scratching away at it, and they're getting some concrete information in there.

Robert: Yeah, I mean historically the results have varied depending on what's going into it, and they're varied from there being one, one by one civilization out there to millions so.

Julie: Yeah, right. Again, there's a lot of data that needs to be plugged in here, but astronomers, if you will, plugging away at that. Now I wanted to mention the Fermi Paradox and this is something I want you guys - I'll put in your back pocket as you consider all the other information that we talk about today. The Fermi Paradox is from a Nobel Prize winning physicist, Erico Fermi, and he reasoned that if it takes life billions of years to develop intelligence, and signal or travel to the stars and if there are billions of worlds in the universe, and if the universe if over 13 billion years old, then why haven't we've been visited by an extraterrestrial? Or why isn't the galaxy crawling with extraterrestrial, this is something we'll get to later, but that's a good question right?

Robert: Yeah, I mean Steven Hawkin brought up the same thing with time traveler. If time traveler was possible, is possible, will be possible, why not have we been visited by time traveler. Like just kind of a basic show me level of analysis. Okay, there's aliens great, show me one, show me the alien, put it on the table for me to see.

Julie: Because the time traveler erased our memory.

Robert: Certainly you can roll out varying levels of conspiracy and exclamation on top of it, but at the very root it's just a question of all right if there's aliens then we should have seen them, we should see them, and then you can apply your own excuses as to why we have not.

All right, on that note we're gonna actually call this an episode. We're splitting the study episode up into two episodes, so this was Part 1. Part 2 will publish very shortly, so be on the lookout for that. In the time being if you have any kind of feedback on Part 1, you can find us on Facebook and you can find us on Tumblir. We are Stuff to Blow Your Mind on both of those, and we use the handle blowthemind on Twitter.

Julie: And you can always drop us a line at For more on this and thousands of other topics visit

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Duration: 19 minutes