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Speaker 1: Humans have been looking at the night sky and asking

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Speaker 1: basic questions about it for a long time. What are

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Speaker 1: those points of light? Why do some of them move?

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Speaker 1: Are their patterns that we can understand? And though it's

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Speaker 1: taken us thousands of years, we've actually made a lot

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Speaker 1: of progress.

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Speaker 2: In figuring it out.

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Speaker 1: Unlike our ancient ancestors, we know something about what we're

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Speaker 1: looking at. We can appreciate that the points of light

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Speaker 1: are not nearby, but our mind bogglingly distant, that we're

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Speaker 1: looking at over a vast black ocean of space, seeing

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Speaker 1: the few and incredibly distant islands of light in the cosmos,

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Speaker 1: it's really one of the most spectacular views you'll ever see.

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Speaker 1: And from that view we have extrapolated quite incredibly into

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Speaker 1: an understanding of the bigger picture of the universe. We

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Speaker 1: now know a lot about how vast the universe is,

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Speaker 1: how galaxies form, how they cluster, how the universe expands.

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Speaker 1: But in all of those thousands of years, we've made

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Speaker 1: almost zero progress on one of the most basic questions,

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Speaker 1: one of the most pressing. And as we've been able

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Speaker 1: to expand our mental picture of the universe from just

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Speaker 1: the neighborhood of Earth, to the ninety some billion light

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Speaker 1: years of the observable universe, this unanswered question has just

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Speaker 1: become more pressing. That question is, of course, are we alone?

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Speaker 1: As we stare up into the night sky and do

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Speaker 1: our best to unravel its workings, to put pen to

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Speaker 1: paper and capture the mechanisms of the universe in our

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Speaker 1: little mathematical stories, we wonder if we are the only

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Speaker 1: ones doing that. Is there someone else up there around

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Speaker 1: a distant planet looking back at us, wondering if we

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Speaker 1: two are here and looking back at them? Well, until

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Speaker 1: the aliens arrive, or send us an email, Instagram, DM

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Speaker 1: or LinkedIn connection request, do we have any hope of

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Speaker 1: figuring this out? We have managed to learn incredible things

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Speaker 1: about the nature of the wider universe without ever leaving

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Speaker 1: the immediate neighborhood of our planet, just from gathering the

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Speaker 1: photons that happen.

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Speaker 2: To splash down here.

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Speaker 1: Can we do the same to understand the prevalence of

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Speaker 1: alien life, what it might be like, and whether it

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Speaker 1: thinks and wonders and eats and screams When this steps

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Speaker 1: on a lego at three am. We are curious humans,

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Speaker 1: and so we are never satisfied just throwing our hands

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Speaker 1: in the air and giving up because it's hard. We

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Speaker 1: want to extract every last bit of knowledge from the

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Speaker 1: rare data that we have, So on today's episode, we're

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Speaker 1: going to explore one particular theory that tries to answer

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Speaker 1: the age old question, is life rare in the universe?

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Speaker 3: Hi, I'm Kelly Leener Smith. I'm an edge of faculty

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Speaker 3: at University, and welcome to Daniel and Kelly's Extraordinary Universe.

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Speaker 3: We're happy to have you here, and I'm here with

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Speaker 3: my co host Daniel.

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Speaker 2: Hey. Everyone, I'm Daniel.

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Speaker 1: I'm a particle physicist and a professor at UC Irvine,

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Speaker 1: and I'm so happy to be here today with you

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Speaker 1: Kelly on our extraordinary podcast about the Extraordinary Universe.

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Speaker 3: Yeah, super exciting. I have an extraordinary question for you.

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Speaker 3: So I wrote this book about space, which means I

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Speaker 3: get to talk to the space community. The question that

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Speaker 3: I get most often that I don't know how to answer.

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Speaker 3: I'm going to ask you what you think is what

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Speaker 3: about all that UFO stuff that we've been hearing about lately,

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Speaker 3: like the Senate hearing and stuff. What is your thought

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Speaker 3: on the UFO situation?

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Speaker 2: My thought is that.

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Speaker 1: There are two totally different categories of work. One is

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Speaker 1: like real scientific questions about where alien life might be

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Speaker 1: and how we might find it, and like hard hitting

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Speaker 1: scientific projects to look for bios signatures or out other stars.

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Speaker 1: And then there's ufology, which is a very fascinating community

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Speaker 1: of folks who desperately want to believe that aliens are

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Speaker 1: already here and the government is covering it up somehow,

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Speaker 1: and the fact that we don't have evidence for it

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Speaker 1: is somehow evidence of that cover up. And there are

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Speaker 1: some folks in there who are doing their best try

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Speaker 1: to sort through the evidence in a methodical way. And

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Speaker 1: I think there are also a lot of gristers in

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Speaker 1: there who are playing on people who really want to believe.

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Speaker 1: And I think you'll find a lot of scientists are

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Speaker 1: eager to dig into the alien life stuff and eager

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Speaker 1: to avoid the conspiracy theories of ufology.

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Speaker 3: I think our takes pretty much agreed. If anybody wants

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Speaker 3: to check my Goodreads account, there's this great book and

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Speaker 3: I'm forgetting the title and the name, which is very helpful,

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Speaker 3: But there was a woman who essentially engaged with the

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Speaker 3: UFO community, and it was sort of like an anthropological

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Speaker 3: look at that community, and it was a very fun

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Speaker 3: book to read. But my take on most of these

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Speaker 3: things that are coming through the Senate hearing is that

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Speaker 3: it's probably technology from some other country that's like in

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Speaker 3: our airspace and we happen to run upon it at

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Speaker 3: the wrong time and they didn't mean for us to

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Speaker 3: see it, or it's a US technology that we're working

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Speaker 3: on and some pilot saw it when they weren't supposed to.

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Speaker 3: I think there's almost always some explanation that doesn't require aliens.

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Speaker 3: And it would also surprise me if aliens like came

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Speaker 3: and were accidentally seen and then left, like that's a

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Speaker 3: long journey to just like go home. Yeah, But anyway,

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Speaker 3: I think we're on the same page.

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Speaker 1: No, I totally agree, and I want to emphasize that,

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Speaker 1: like I want to believe if there was really any

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Speaker 1: sort of shred of hard evidence that we could dig

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Speaker 1: into about aliens, I would be the first one to

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Speaker 1: trumpet it. I'm definitely a mark for these folks, and

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Speaker 1: I want to believe it, but it just doesn't really

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Speaker 1: hold up. But I know that what we've seen is

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Speaker 1: a tiny fraction of what the government has, which is

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Speaker 1: something that the UFO community talks about a lot. I

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Speaker 1: actually once had a congressman reach out to me say, Daniel,

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Speaker 1: I have questions about what I've been shown. Can we talk?

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Speaker 1: And so I gave him a call, of course, and

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Speaker 1: I tried to explain to him what we were looking

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Speaker 1: at and what we knew and what phys said and

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Speaker 1: what we didn't know about the universe. And then I

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Speaker 1: asked him, I said, hey, have you seen all the

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Speaker 1: classified footage from the DUD He said, yes, I have,

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Speaker 1: and I said what's in it? And he says, nothing interesting.

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Speaker 1: It's all drones and balloons, and it's less interesting than

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Speaker 1: the stuff you have seen, which was like exciting to

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Speaker 1: get a glimpse behind the scenes, but also deflating because

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Speaker 1: I was really hoping he was going to say, oh,

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Speaker 1: with amazing stuff, you won't believe it when they finally

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Speaker 1: release it.

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Speaker 2: So unfortunately, but I do want to believe.

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Speaker 1: I'm waiting for the day that the aliens come and

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Speaker 1: I will be first in line to talk to them

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Speaker 1: about the secrets.

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Speaker 2: Of the universe.

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Speaker 3: I'm excited too, and I think if our species persists

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Speaker 3: long enough, it's just a matter of time before we

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Speaker 3: encounter something. But this is a good transition into today's topic.

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Speaker 3: So the title of today's show is is life rare

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Speaker 3: in the universe? So what is the probability that there's

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Speaker 3: life out there that we could encounter. We've reached out

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Speaker 3: to the listeners and we told them that one approach

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Speaker 3: to thinking about life in the universe is the rare

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Speaker 3: Earth hypothesis. We wanted to know what they had heard

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Speaker 3: about this, and here are their responses.

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Speaker 4: I think the rare Earth hypothesis is the idea that

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Speaker 4: Earth and specifically its conditions for life are really rare

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Speaker 4: in the universe, and that life being able to form

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Speaker 4: is rare because a planet able to support life is rare.

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Speaker 5: I don't know, but I think it's that Earth is

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Speaker 5: the only planet that has life that we know of.

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Speaker 6: I think the rare Earth hypothesis has to do with

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Speaker 6: how common it is that a planet just like ours

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Speaker 6: would form with all the crazy factors that went into

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Speaker 6: our history, or it has to do with the composition

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Speaker 6: of elements that we can find in our crust, mantle,

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Speaker 6: and core. Either way, rare.

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Speaker 7: Earth planets that can foster life orbit in the Goldilock zone,

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Speaker 7: allowing for liquid water. They have a molten core, iron core,

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Speaker 7: creating a magnetic field protecting it from high energy, harmful radiation,

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Speaker 7: and many other characteristics required to sustain life. So I

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Speaker 7: think the rare Earth hypothesis hypothesizes its rare but possible

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Speaker 7: to have planets swiat to Earth throughout the universal.

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Speaker 5: Because I have no idea, I will use context clues

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Speaker 5: and say maybe it has something to do with minerals.

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Speaker 8: The rare Earth hypothesis is the way our earthborn does

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Speaker 8: compared to other rocky planets and other solo systems. Is

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Speaker 8: not a common occurrence, Like it's rare, Like we don't

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Speaker 8: see them every day.

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Speaker 3: All right, Daniel, what do you think?

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Speaker 1: Yeah, I think the listeners are right on here. The

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Speaker 1: rare hypothesis is one of those ideas in science that

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Speaker 1: is rare because it's well named, you know, you can

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Speaker 1: actually understand what it means.

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Speaker 2: Run the title. It's a hypothesis that.

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Speaker 1: Earth is rare, that life on Earth is rare, that

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Speaker 1: our existence is unusual in the universe, which of course

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Speaker 1: would be a devastating outcome for those of us who

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Speaker 1: hope that the universe is builled with all sorts of

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Speaker 1: intelligent alien life we can one day talk to. But

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Speaker 1: it's a possibility we have to face, right, It's one

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Speaker 1: of the potential outcomes to this question. Are we alone

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Speaker 1: in the universe? It might be yes, it might be

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Speaker 1: that we're the only thinking creatures out there trying to

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Speaker 1: understand how the universe works.

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Speaker 3: Yeah. Maybe, or maybe they've just seen human history and

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Speaker 3: they're like, they're just not ready for us yet. So

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Speaker 3: every conversation about aliens has to start with the Drake equation,

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Speaker 3: which I think is both interesting and useful. I've reviewed

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Speaker 3: a lot of proposals for students who are into science communication,

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Speaker 3: and almost everyone who's in physics wants to do a

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Speaker 3: video about the Drake equation, and so I'm like, I'm

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Speaker 3: kind of over it. Oh no, it's like mitosis for biologists,

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Speaker 3: Like everybody does the video on mitosis. But all right,

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Speaker 3: so Daniel the bar is high. Make the Drake equation

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Speaker 3: interesting to me again, like it was the first time

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Speaker 3: I heard it.

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Speaker 1: All right, all right, Well, this episode is not just

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Speaker 1: about the Drake equation, but I think that Drake equation

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Speaker 1: is a very useful way to organize our thinking. Like, look,

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Speaker 1: this is a big problem, right, is there life elsewhere

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Speaker 1: in the.

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Speaker 2: Universe and in science.

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Speaker 1: When we tackle a really big problem, what our strategies

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Speaker 1: is like, hey, break it into pieces. You know, every

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Speaker 1: time I have a big research project, I don't know

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Speaker 1: how many get from here to there. You got to

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Speaker 1: break it into steps and then take on each of

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Speaker 1: those steps. And the Drake equation is just that. It

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Speaker 1: is to say, look, if there is going to be

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Speaker 1: life elsewhere in the universe, then a lot of things

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Speaker 1: have to line up. You need to have enough stars,

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Speaker 1: you need to have enough planets around those stars, you

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Speaker 1: need to have life on those planets. That life has

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Speaker 1: to develop intelligence, that intelligence has to be technological. And

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Speaker 1: so it breaks it up into all these sub questions like, well,

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Speaker 1: we can think about how many stars there are, and

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Speaker 1: we can think about the physics of whether there are

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Speaker 1: planets around them, and we can argue about whether there

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Speaker 1: is life on planets or what the.

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Speaker 2: Probability of those is.

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Speaker 1: So it's a really useful way to try to think

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Speaker 1: about the problem. It also shows you how hard this

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Speaker 1: problem is because you know, how do you know what

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Speaker 1: fraction of planets have life on them? Remember that all

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Speaker 1: the information we have comes either from Earth or from

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Speaker 1: the a few Measley photons that have crawled their way

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Speaker 1: through the universe to get to Earth, and so it's

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Speaker 1: a really difficult task, but that doesn't mean we shouldn't

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Speaker 1: take it on, Right, Every really big question in science

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Speaker 1: got started at some point when people were like, hmm,

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Speaker 1: this seems really hard. What's the first thing we can

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Speaker 1: do to tackle it? So, to me, the Drake equation

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Speaker 1: is just like, hey, let's take a step towards answering

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Speaker 1: this really hard but really important problem.

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Speaker 3: Yeah, I think that's fair. Figuring out the like parameters

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Speaker 3: that need to be measured and trying to get a

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Speaker 3: handle on the errors in our data, those are all

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Speaker 3: good things to do. When was the Drake equation proposed?

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Speaker 3: Because I think we have actually like made pretty good

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Speaker 3: progress on getting sort of estimates for some of these

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Speaker 3: things since the Drake equation was proposed, Right, Yeah.

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Speaker 1: The Drake equation is pretty old by now. It's nineteen

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Speaker 1: sixty one by Frank Drake, famous astronomer, of course, and

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Speaker 1: so that's you know, sixty years ago, and we definitely

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Speaker 1: know a lot more about some of these numbers than

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Speaker 1: we did when it was first proposed, which is really

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Speaker 1: fascinating because in the Earth they had to do a

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Speaker 1: lot more sort of guessing, and it's interesting to read

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Speaker 1: like what Carl Sagan thought about these things. He was

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Speaker 1: a big believer in this principle of mediocrity. I mean,

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Speaker 1: I know, his famous quote is like extraordinary claims require

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Speaker 1: extraordinary evidence. But he also hit hard on this principle

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Speaker 1: of mediocrity, which I think is fascinating. And it's a

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Speaker 1: very simple argument. It says, like, look, if you only

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Speaker 1: have one example of something, probably it's a typical example.

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Speaker 1: You know, imagine, for example, you have a bag full

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Speaker 1: of marbles, You draw one. It's an orange one. What

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Speaker 1: are the chances it's the only orange marble in a

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Speaker 1: bag of millions of marbles. Pretty small? Probably it's the

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Speaker 1: most likely kind of marble. Right, Probably it's mostly orange marbles.

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Speaker 1: So that's a pretty basic argument, and Carl Sagan uses

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Speaker 1: it to suggest, Hey, look there's life here on Earth.

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Speaker 2: There's planets around this star. You know, we.

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Speaker 1: Develop technological civilization. So probably all of these numbers in

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Speaker 1: the Drake equation are not zero or very very very

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Speaker 1: close to zero. They're probably around half right. And so

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Speaker 1: that's like a really powerful, not that convincing, but useful

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Speaker 1: first argument to say, like Hey, look, life in the

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Speaker 1: universe shouldn't be rare, and it's sort of astonishing how

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Speaker 1: far you can get from just like, hey, we're going

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Speaker 1: to write down all the numbers you have to multiply

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Speaker 1: together to calculate the number of alien species. We're going

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Speaker 1: to make this very vague argument, and then we're going

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Speaker 1: to basically conclude that life is everywhere in the universe.

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Speaker 3: So, I don't remember, does the Drake equation give you

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Speaker 3: an estimated number of intelligent civilizations out there or like

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Speaker 3: a probability of finding it? And are there recent estimates

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Speaker 3: that we could point to.

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Speaker 1: Yeah, So the Drake equation calculates the number of civilizations

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Speaker 1: in the galaxy with which communication might be possible. Right,

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Speaker 1: So it has the rate of star formation in the galaxy,

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Speaker 1: the fraction of those that have planets, the number of

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Speaker 1: planets that have life, the fraction of those that actually

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Speaker 1: develop life, the fraction of those that have intelligent life,

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Speaker 1: fraction of those that have civilization, and then the time that.

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Speaker 2: They survive like the length of their Bible.

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Speaker 1: Because if aliens are civilized for only five seconds before

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Speaker 1: they nuke themselves to smithereens, then we're not likely to

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Speaker 1: hear from them. We might get the shock waves from

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Speaker 1: their nuclear holocaust, but that's not exactly communication.

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Speaker 3: Yeah, No, I mean that would be a lesson that

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Speaker 3: would be important to learn that.

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Speaker 1: Yeah, but you're right that More recently people have started

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Speaker 1: to wonder about this because we've learned some things about

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Speaker 1: these numbers, Like we know that there are billions and

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Speaker 1: billions more than one hundred billion stars in the Milky Way,

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Speaker 1: so like we're starting from a really big number. And

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Speaker 1: more recently we've learned thanks to exoplanets, that there are

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Speaker 1: a lot of planets out there. There's like many planets

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Speaker 1: per star, and a significant fraction of stars out there

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Speaker 1: have Earth like planets inhabitable zone, you know. So that's

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Speaker 1: not a tiny number. So now we're talking like tens

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Speaker 1: of billions of rocky planets out there in the Milky Way.

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Speaker 1: And even a few decades after the drig equation, people

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Speaker 1: were wondering, like, hmm, there are all these stars out

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Speaker 1: there in the galaxy, there are all these planets out there.

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Speaker 1: Life can't be that rare to form, So where are

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Speaker 1: all the aliens?

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Speaker 4: Right?

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Speaker 1: And so that's the famous Fermi paradox. People are wondering

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Speaker 1: like Sagan's principle of mediocrity, and the Drake equation all

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Speaker 1: suggests that the universe should be teeming with life, that

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Speaker 1: the galaxy should be overflowing with life, and also crucially,

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Speaker 1: that there's time for it to have reached us. Like,

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Speaker 1: the galaxy is about one hundred thousand light years across,

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Speaker 1: and it's more than ten billion years old, So there's

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Speaker 1: time for like a civilization to flourish, to form, to

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Speaker 1: travel the stars, to even explore the galaxy. I once

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Speaker 1: sat down and calculated, like, how long would it take

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Speaker 1: for a civilization to send a probe to every single

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Speaker 1: rocky planet in the galaxy? And the answer is not

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Speaker 1: that long. If you can build self replicating probes that

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Speaker 1: land on a planet, do a little bit of mining,

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Speaker 1: make more of themselves, then the number of probes grows exponentially,

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Speaker 1: and so it takes like much less than a million

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Speaker 1: years to explore the entire galaxy. In the galaxies billions

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Speaker 1: of years old, surely somebody would have thought of this idea.

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Speaker 1: I mean, if I've had this idea and other people

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Speaker 1: have had it, certainly some clever alien has done it,

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Speaker 1: and yet we haven't been visited as far as we

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Speaker 1: know by self replicating alien robots.

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Speaker 3: But timing matters too, So you know, if those self

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Speaker 3: replicating alien robots showed up in the age of the dinosaurs,

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Speaker 3: then they would have missed us.

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Speaker 1: The Drick equation definitely accommodates those windows. And you're right

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Speaker 1: that self replicating anian robots had shown up in the

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Speaker 1: age of the dinosaurs, we wouldn't have been here to

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Speaker 1: greet them. But you know, they might have left a mark,

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Speaker 1: and maybe we'll discover traces of them on the Moon

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Speaker 1: or something, and they probably would have replicated themselves and

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Speaker 1: occupied nearby solar systems. I don't know that they would

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Speaker 1: have been really subtle, but hey, maybe that's a possibility.

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Speaker 1: It's certainly one of the answers to this question of

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Speaker 1: the Fermi paradox of where is everybody? Why haven't we

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Speaker 1: been yet visited by aliens? If it seems like the

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Speaker 1: universe should be filled with them. It's not like a

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Speaker 1: claim that there have to be aliens out there. It's

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Speaker 1: more like a response to say this argument. It says, like, okay,

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Speaker 1: you make that argument. It suggests that there should be

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Speaker 1: aliens everywhere, but there aren't, So what's.

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Speaker 2: Wrong, right? Which piece have we misunderstood?

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Speaker 3: Sure, and the co host with anxiety and insecurity is thinking,

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Speaker 3: maybe we're the stinky kids and that's why we haven't

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Speaker 3: been visited. But let's assume that it's not about us,

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Speaker 3: that it's not that they just dislike us. So one

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Speaker 3: rebuttal here is that actually we've overestimated the probability that

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Speaker 3: there's intelligent life out there that could visit us. And

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Speaker 3: this is the rare Earth hypothesis. And we will dive

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Speaker 3: into the rare Earth hypothesis after this break. All right, Daniel,

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Speaker 3: We're not the stinky kids in the universe. I'm sure

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Speaker 3: of it.

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Speaker 1: Wait, first, I want to know why that makes you

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Speaker 1: feel like if we are rejected by aliens, you're going

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Speaker 1: to take that personally, like it matters to you what

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Speaker 1: aliens think.

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Speaker 3: I would be a little bit bummed out if there

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Speaker 3: was like a network of alien civilizations that were all

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Speaker 3: sort of sharing secrets and information about science together, but

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Speaker 3: they just decided that the humans were not quite ready

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Speaker 3: for it. Maybe we're too violent at this point and

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Speaker 3: we couldn't handle what they had to teach us. That

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Speaker 3: would kind of bum me out. I think my psychiatrist

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Speaker 3: calls that catastrophizing. It would bum me out if there

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Speaker 3: were aliens and they decided we're not worth talking to you.

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Speaker 3: What about you?

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Speaker 1: Well, it would bum me out, but not in a

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Speaker 1: personal way. I wouldn't feel like, Wow, all the cool

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Speaker 1: kids don't think I'm cool. I just feel like it'd

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Speaker 1: be a tragedy if they're out there and we don't

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Speaker 1: get to meet them. We're going to learn about how

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Speaker 1: the universe works and how life could be so different

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Speaker 1: or so similar to ours.

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Speaker 2: It just seems like.

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Speaker 1: A tragic, missed opportunity. So it's not really important to

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Speaker 1: me that aliens think we're awesome or that we smell good.

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Speaker 1: But I do want to meet them. So anything that

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Speaker 1: stands in the way of that is definitely a big bummer.

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Speaker 3: Yeah, and all right, So the rare Earth hypothesis posits

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Speaker 3: that we should expect to see life like ours much

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Speaker 3: less in the universe. So give me some background here.

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Speaker 3: Whose idea is this?

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Speaker 2: Yeah, So the Rare.

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Speaker 1: Earth hypothesis came out around two thousand. It's a famous

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Speaker 1: book by the astronomer Donald Brownlee and the geologist Peter Ward,

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Speaker 1: and they try to take a careful look at some

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Speaker 1: of these numbers, like how often is there a planet

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Speaker 1: in a habitable zone that could develop life like ours?

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Speaker 1: What are the conditions that are really necessary and how

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Speaker 1: common are those conditions? And again, there's a lot of

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Speaker 1: guesswork here, but there's always going to be a lot

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Speaker 1: of guesswork. You can't just criticize any work in this

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Speaker 1: area by saying it's not definitive. You know, the first

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Speaker 1: steps are never definitive. But their studies lead them to

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Speaker 1: conclude the opposite of Sagan. Sagan says, you know, hey,

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Speaker 1: we should be typical because we're one of many. But

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Speaker 1: they say, essentially, maybe we're the only one of many

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Speaker 1: because we're unusual, we're weird, and we're different, and we're

402
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Speaker 1: the only place in the universe that life could arise.

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Speaker 1: So their argument is that we're not typical. There are

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Speaker 1: not many other cases. You know, that we are the

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Speaker 1: one orange marble from the bag, and that's why we're

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Speaker 1: the ones asking the question.

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Speaker 3: We're one and there's not many.

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Speaker 2: Yeah, that's right, Yeah, okay, got it.

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Speaker 3: Got it. What factors did we look into then to

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Speaker 3: be the ones who ended up evolving as the intelligent species?

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Speaker 2: Yeah?

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Speaker 1: So I like their book a lot because it does

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Speaker 1: dig into the details of what it takes for.

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Speaker 2: Life to form, and they start big.

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Speaker 1: So let's think about the galaxy, like where in a

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Speaker 1: typical galaxy could you have life. We talked about one

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Speaker 1: hundred billion stars, but could you really have intelligent life

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Speaker 1: around all of those stars? And it turns out the

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Speaker 1: answer is no. There's a lot of the galaxy that's

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Speaker 1: basically a dead zone for life like hours. So, for example,

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Speaker 1: if you're near the center of the galaxy, there's a

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Speaker 1: lot more radiation. Like we talk about often, how out

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Speaker 1: in space, it's not just a vacuum where there's nothing.

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Speaker 1: There's a lot of radiation out there in space. Astronauts

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Speaker 1: to get dosed with radiation on the Internet space station.

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Speaker 1: They have basically a panic room where they can go

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Speaker 1: if there's a solar flare. Space is filled with flying

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Speaker 1: particles that will kill you, and we're buffered from that

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Speaker 1: because of our atmosphere. But also our solar system is

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Speaker 1: not of the most intensely radiation filled part of the galaxy.

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Speaker 2: As you get.

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Speaker 1: Closer and closer to the center, the black hole and

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Speaker 1: all the other stars are pumping out a lot of

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Speaker 1: radiation that could really damage you.

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Speaker 3: This is a different kind of radiation, So maybe this

436
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Speaker 3: argument isn't a good one. But so like, there's fungus

437
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Speaker 3: that are growing in like the abandoned Chernobyl nuclear reactors,

438
00:21:34,080 --> 00:21:38,840
Speaker 3: and so there are apparently species that can handle much

439
00:21:39,400 --> 00:21:42,240
Speaker 3: higher levels of radiation. They do it better than humans do.

440
00:21:42,720 --> 00:21:47,040
Speaker 3: Maybe Merlin Sheldrake or some other fungus enthusiasts would say

441
00:21:47,040 --> 00:21:49,439
Speaker 3: that they communicate intelligently with one another, But I know

442
00:21:49,480 --> 00:21:51,280
Speaker 3: that's not what we're quite talking about. But could there

443
00:21:51,280 --> 00:21:54,000
Speaker 3: be species that are intelligent and are just way more

444
00:21:54,119 --> 00:21:55,880
Speaker 3: radiation resistant than we are?

445
00:21:56,600 --> 00:21:58,400
Speaker 1: Of course there might be, right, and you put your

446
00:21:58,400 --> 00:22:03,000
Speaker 1: finger on the fundamentalntal weakness of this entire argument, which

447
00:22:03,119 --> 00:22:06,439
Speaker 1: is that they're thinking about lifelike hours. Sure, if you

448
00:22:06,480 --> 00:22:09,600
Speaker 1: took humans and you teleported them to some planet around

449
00:22:09,600 --> 00:22:11,600
Speaker 1: a star close to the center of the galaxy, they

450
00:22:11,640 --> 00:22:13,760
Speaker 1: wouldn't last very long. They'd all get cancer, and it

451
00:22:13,760 --> 00:22:16,879
Speaker 1: wouldn't be very fun because lifelike ours didn't evolve.

452
00:22:16,560 --> 00:22:19,160
Speaker 2: In those conditions. But it's much harder to.

453
00:22:19,119 --> 00:22:23,520
Speaker 1: Say could life that's not like ours arise under different conditions?

454
00:22:23,680 --> 00:22:25,919
Speaker 1: And that's really the challenge of thinking about alien life

455
00:22:26,080 --> 00:22:28,680
Speaker 1: is thinking out of the box of earth like life.

456
00:22:29,160 --> 00:22:32,600
Speaker 1: So really this book is asking what's the probability of

457
00:22:32,800 --> 00:22:36,840
Speaker 1: earth like life arising not on Earth, which of course

458
00:22:36,960 --> 00:22:39,000
Speaker 1: is going to be a small number. And so that's

459
00:22:39,040 --> 00:22:41,719
Speaker 1: the fundamental criticism of this book. You really put your

460
00:22:41,720 --> 00:22:44,359
Speaker 1: finger on it. But it does highlight how different the

461
00:22:44,400 --> 00:22:47,520
Speaker 1: conditions are in different parts of the galaxy and therefore

462
00:22:47,560 --> 00:22:50,640
Speaker 1: how different life might be. If you are evolving close

463
00:22:50,640 --> 00:22:52,920
Speaker 1: to the center of the galaxy and near the black hole,

464
00:22:53,200 --> 00:22:55,760
Speaker 1: you're going to somehow have to have a different biochemistry

465
00:22:55,920 --> 00:22:58,600
Speaker 1: because you're getting pummeled by radiation all the time, and

466
00:22:58,640 --> 00:23:00,440
Speaker 1: maybe you figure it out a way to take advantage

467
00:23:00,440 --> 00:23:02,720
Speaker 1: of that. Maybe radiation is like lunch for you, right.

468
00:23:03,800 --> 00:23:07,280
Speaker 3: I wonder if these factors would also influence like the

469
00:23:07,480 --> 00:23:10,640
Speaker 3: order that visits would have to happen. Like humans couldn't

470
00:23:10,720 --> 00:23:14,080
Speaker 3: go towards a high radiation area to like try to

471
00:23:14,080 --> 00:23:16,720
Speaker 3: meet those aliens because we'd get cancer and die. But

472
00:23:17,320 --> 00:23:21,640
Speaker 3: organisms that are from a high radiation part of the

473
00:23:21,720 --> 00:23:25,280
Speaker 3: galaxy could come visit us if they could handle less radiation.

474
00:23:25,359 --> 00:23:27,479
Speaker 3: Unless they're eating radiation, then they might be very hungry,

475
00:23:28,000 --> 00:23:29,960
Speaker 3: but we could feed them at Chernobyl or something.

476
00:23:30,200 --> 00:23:30,919
Speaker 2: Yeah exactly.

477
00:23:31,240 --> 00:23:32,960
Speaker 3: I guess you don't have to physically go somewhere to

478
00:23:32,960 --> 00:23:33,960
Speaker 3: communicate with someone.

479
00:23:34,080 --> 00:23:34,679
Speaker 2: Yeah, that's right.

480
00:23:34,720 --> 00:23:37,440
Speaker 1: I think the Drake equation is mostly thinking about communication,

481
00:23:37,920 --> 00:23:39,959
Speaker 1: But of course I want to meet the aliens. And

482
00:23:40,200 --> 00:23:42,640
Speaker 1: I think if we found a civilization near the center

483
00:23:42,640 --> 00:23:45,040
Speaker 1: of the galaxy that was eating radiation, we just have

484
00:23:45,119 --> 00:23:47,160
Speaker 1: to develop good technology to protect ourselves.

485
00:23:47,320 --> 00:23:48,960
Speaker 2: We could probably figure out how to get there.

486
00:23:49,320 --> 00:23:51,199
Speaker 1: But it's fascinating to think about which parts of the

487
00:23:51,200 --> 00:23:53,639
Speaker 1: galaxy life could evolve in and how it would be different.

488
00:23:54,080 --> 00:23:56,440
Speaker 1: So there's the center of the galaxy filled with radiation.

489
00:23:56,560 --> 00:23:59,840
Speaker 1: That's a dead zone for lifelike hours. It's also less

490
00:23:59,880 --> 00:24:02,520
Speaker 1: likely to develop lifel like hours at the edge of

491
00:24:02,560 --> 00:24:06,400
Speaker 1: the galaxy, like far out from the center is also

492
00:24:06,520 --> 00:24:09,080
Speaker 1: not a great place to have life like ours because

493
00:24:09,320 --> 00:24:11,800
Speaker 1: far out there the stars have less metal, so the

494
00:24:11,840 --> 00:24:15,320
Speaker 1: solar systems have less like hard rocky stuff in order

495
00:24:15,359 --> 00:24:16,360
Speaker 1: to build life.

496
00:24:16,600 --> 00:24:18,800
Speaker 3: So does that mean you're more likely to get gas

497
00:24:19,000 --> 00:24:20,920
Speaker 3: giants that you can't land on out there?

498
00:24:21,680 --> 00:24:24,600
Speaker 1: Yeah exactly. And remember where stuff comes from in the universe.

499
00:24:24,880 --> 00:24:27,119
Speaker 1: Very abbreviated history of the universe is you have like

500
00:24:27,160 --> 00:24:29,879
Speaker 1: protons and electrons, and they form hydrogen. So most of

501
00:24:29,920 --> 00:24:32,720
Speaker 1: the universe is hydrogen, with a little bit of helium

502
00:24:33,040 --> 00:24:36,320
Speaker 1: from fusion during the Big Bang. But then the universe

503
00:24:36,400 --> 00:24:38,960
Speaker 1: is just like clouds of hydrogen for a long long time,

504
00:24:39,040 --> 00:24:42,399
Speaker 1: and that hasn't really changed. You know, we have stars

505
00:24:42,400 --> 00:24:44,840
Speaker 1: that have formed and have made helium and carbon and

506
00:24:44,960 --> 00:24:47,320
Speaker 1: nitrogen and oxygen all the way up to iron, and

507
00:24:47,359 --> 00:24:49,960
Speaker 1: then we have supernova that make really heavy stuff. But

508
00:24:50,000 --> 00:24:52,600
Speaker 1: the fraction of the universe that is anything but hydrogen

509
00:24:52,640 --> 00:24:56,000
Speaker 1: and helium is still pretty small. So this is the

510
00:24:56,040 --> 00:24:59,960
Speaker 1: stuff that like makes life interesting, It makes complicated biochemistry possible,

511
00:25:00,320 --> 00:25:03,119
Speaker 1: and like you know, information storage and DNA, all that

512
00:25:03,160 --> 00:25:06,640
Speaker 1: stuff needs more complex molecules. Those who rely on those

513
00:25:06,640 --> 00:25:09,720
Speaker 1: heavier atoms, and those are still pretty rare, and they

514
00:25:09,760 --> 00:25:12,000
Speaker 1: tend to be near the center of the galaxy. That's

515
00:25:12,040 --> 00:25:15,359
Speaker 1: where the masses the heavy stuff falls there, and so

516
00:25:15,560 --> 00:25:18,640
Speaker 1: out in the sort of backwaters of the galaxy there

517
00:25:18,680 --> 00:25:22,240
Speaker 1: are fewer metals, and so yeah, you have stars there

518
00:25:22,280 --> 00:25:25,439
Speaker 1: that are more hydrogen, more helium, less metallic, which changes

519
00:25:25,640 --> 00:25:28,439
Speaker 1: how they operate. And then you have fewer rocky planets

520
00:25:28,440 --> 00:25:31,080
Speaker 1: and more gas giants, and again that's bad for life,

521
00:25:31,440 --> 00:25:34,120
Speaker 1: Like hours. But if you're some sort of weird alien

522
00:25:34,520 --> 00:25:37,000
Speaker 1: that's like a plasma cyclone in a star, you don't

523
00:25:37,000 --> 00:25:37,480
Speaker 1: really care.

524
00:25:37,960 --> 00:25:39,080
Speaker 2: Or if you're a weird.

525
00:25:38,800 --> 00:25:42,040
Speaker 1: Alien that evolved in the clouds of a gas giant,

526
00:25:42,119 --> 00:25:43,720
Speaker 1: you also don't necessarily care.

527
00:25:44,320 --> 00:25:46,719
Speaker 2: But for lifelike hours, it would be harder to evolve

528
00:25:47,160 --> 00:25:49,000
Speaker 2: far away from the center of the galaxy.

529
00:25:49,200 --> 00:25:52,200
Speaker 3: In our atmosphere, there's bacteria that are you know, floating

530
00:25:52,200 --> 00:25:54,520
Speaker 3: around up in the sky in the clouds and stuff

531
00:25:54,560 --> 00:25:57,360
Speaker 3: like that. You couldn't even get stuff like that at

532
00:25:57,359 --> 00:26:00,720
Speaker 3: the far reaches of the galaxy because bacteria have more

533
00:26:00,920 --> 00:26:03,440
Speaker 3: than hydrogen and helium in them.

534
00:26:03,200 --> 00:26:04,080
Speaker 2: Yeah, exactly.

535
00:26:04,119 --> 00:26:06,600
Speaker 1: And it's not like there're no metals out there, it's

536
00:26:06,640 --> 00:26:09,840
Speaker 1: just rarer and so that like suppresses the chances for

537
00:26:09,880 --> 00:26:12,439
Speaker 1: all those kind of stuff happening. So that makes the

538
00:26:12,480 --> 00:26:16,760
Speaker 1: galaxy have like a window of habitability, you know, habitable zone.

539
00:26:16,800 --> 00:26:18,720
Speaker 1: You can't get too close to the center or you

540
00:26:18,760 --> 00:26:21,040
Speaker 1: get fried. You can't get too far out, or there

541
00:26:21,040 --> 00:26:23,919
Speaker 1: aren't enough of the building blocks. And then in the

542
00:26:23,960 --> 00:26:26,800
Speaker 1: habitable zone you're not even safe. Like there are places

543
00:26:26,800 --> 00:26:29,200
Speaker 1: in the habitable zone that are more dangerous for life

544
00:26:29,280 --> 00:26:31,120
Speaker 1: like ours than other places.

545
00:26:31,440 --> 00:26:34,520
Speaker 3: And how is this danger measured? Does this radiation?

546
00:26:35,600 --> 00:26:38,239
Speaker 1: This is the chances that a nearby star are going

547
00:26:38,280 --> 00:26:41,280
Speaker 1: to come by disturb the Solar System and cause an

548
00:26:41,320 --> 00:26:44,080
Speaker 1: extinction event due to like a comet hitting a planet.

549
00:26:44,600 --> 00:26:47,240
Speaker 1: So the density of stars nearby really affects how likely

550
00:26:47,280 --> 00:26:49,480
Speaker 1: you are to have a comet get nudged from the

551
00:26:49,520 --> 00:26:52,159
Speaker 1: outer Solar System and fall into the inner Solar System

552
00:26:52,320 --> 00:26:55,240
Speaker 1: and impact on your planet and fry everybody. If you

553
00:26:55,280 --> 00:26:58,120
Speaker 1: have a lot of nearby stars, then their little gravitational

554
00:26:58,200 --> 00:27:00,760
Speaker 1: tugs are going to interfere with your Solar system and

555
00:27:00,760 --> 00:27:03,439
Speaker 1: make it very chaotic. If you're pretty far away from

556
00:27:03,480 --> 00:27:04,920
Speaker 1: everybody else, then you're safer.

557
00:27:05,160 --> 00:27:09,560
Speaker 3: But we've been hit by comets and have massive extinction events,

558
00:27:09,560 --> 00:27:13,240
Speaker 3: but still some stuff eaked through and humans popped out.

559
00:27:14,160 --> 00:27:16,840
Speaker 3: They feel like chaos just kind of pushes diversity back

560
00:27:16,960 --> 00:27:20,080
Speaker 3: a little bit. Yeah, and then it rebounds. Whoever makes

561
00:27:20,119 --> 00:27:22,679
Speaker 3: it through. That doesn't seem like a showstop er so

562
00:27:22,800 --> 00:27:25,240
Speaker 3: much as a show slower downer.

563
00:27:26,160 --> 00:27:27,800
Speaker 2: Yeah, and it might also be crucial.

564
00:27:27,880 --> 00:27:30,320
Speaker 1: Right, maybe evolution gets stuck in some local minimum and

565
00:27:30,359 --> 00:27:32,399
Speaker 1: it needs a reboot and needs to get like kicked

566
00:27:32,400 --> 00:27:35,040
Speaker 1: into higher gear. Right, we certainly know that a massive

567
00:27:35,080 --> 00:27:37,160
Speaker 1: impactor played a big role in the history of life

568
00:27:37,160 --> 00:27:39,720
Speaker 1: on Earth, and we wouldn't be here if it hadn't

569
00:27:39,760 --> 00:27:42,119
Speaker 1: hit sixty five million years ago. So I agree with

570
00:27:42,160 --> 00:27:44,920
Speaker 1: you this is not an open and shutcase. But again

571
00:27:44,960 --> 00:27:47,880
Speaker 1: it does show you that elements of the galaxy are different,

572
00:27:48,480 --> 00:27:51,359
Speaker 1: and that growing up in different parts of the galaxy,

573
00:27:51,560 --> 00:27:54,440
Speaker 1: the neighborhoods really are different. There are more crowded neighborhoods

574
00:27:54,440 --> 00:27:57,159
Speaker 1: and then there are quiet and peaceful neighborhoods. And you know,

575
00:27:57,200 --> 00:28:01,280
Speaker 1: where we are in the galaxy changes because the most

576
00:28:01,400 --> 00:28:05,040
Speaker 1: dangerous parts and the habitable zone are in the galactic arms.

577
00:28:05,359 --> 00:28:07,280
Speaker 1: Like you know, the galaxy is a big flat disc,

578
00:28:07,680 --> 00:28:10,080
Speaker 1: but it spins and has these arms. You see these

579
00:28:10,240 --> 00:28:12,600
Speaker 1: when you look at pictures of galaxies, and it's not

580
00:28:12,640 --> 00:28:14,679
Speaker 1: like the Sun is either in the arms or not

581
00:28:14,840 --> 00:28:15,560
Speaker 1: in the arms.

582
00:28:15,680 --> 00:28:17,840
Speaker 2: Those arms pass through the galaxy.

583
00:28:18,200 --> 00:28:20,840
Speaker 1: So sometimes during the galactic cycle, we are in an

584
00:28:20,920 --> 00:28:23,119
Speaker 1: arm and arm passes through us. It's more of a

585
00:28:23,160 --> 00:28:26,560
Speaker 1: density wave than a structure. It's sort of like traffic, right.

586
00:28:26,640 --> 00:28:28,320
Speaker 1: Sometimes you can be on the road there's no traffic,

587
00:28:28,359 --> 00:28:31,199
Speaker 1: and then a traffic wave will pass through you. So

588
00:28:31,240 --> 00:28:34,119
Speaker 1: there are epics when you're inside one of these arms

589
00:28:34,119 --> 00:28:36,280
Speaker 1: and there are more stars around you and more comments

590
00:28:36,280 --> 00:28:37,520
Speaker 1: are hitting your planet.

591
00:28:37,400 --> 00:28:38,560
Speaker 2: For good or for ill.

592
00:28:39,360 --> 00:28:42,400
Speaker 1: But where you are in the galaxy really influences the

593
00:28:42,560 --> 00:28:44,640
Speaker 1: experience of life on that planet.

594
00:28:44,800 --> 00:28:47,680
Speaker 3: What if instead that spurs innovation, Like what if you're

595
00:28:47,760 --> 00:28:49,960
Speaker 3: a civilization that's sort of on the edge of being

596
00:28:50,000 --> 00:28:52,560
Speaker 3: able to do space travel and you're like, all right,

597
00:28:52,560 --> 00:28:54,600
Speaker 3: we really got to figure it out. Our neighborhoods are

598
00:28:54,600 --> 00:28:57,120
Speaker 3: going to be colliding. It's time to go. I can

599
00:28:57,200 --> 00:28:59,360
Speaker 3: imagine that spurring innovation if the timing works out.

600
00:28:59,560 --> 00:28:59,760
Speaker 2: Yeah.

601
00:29:00,000 --> 00:29:02,080
Speaker 1: Think that really highlights the weakness of these arguments that

602
00:29:02,120 --> 00:29:05,640
Speaker 1: you can almost always make the opposite argument, like this

603
00:29:05,680 --> 00:29:08,320
Speaker 1: seems plausible, So does the opposite argument. I guess the

604
00:29:08,360 --> 00:29:11,080
Speaker 1: answer is we really just don't know. And I think

605
00:29:11,120 --> 00:29:13,480
Speaker 1: that's the takeaway message, is like, we really don't know

606
00:29:13,600 --> 00:29:16,000
Speaker 1: anything about any of these questions, and what.

607
00:29:15,960 --> 00:29:18,240
Speaker 2: We really need is more data. We have an equals one.

608
00:29:18,400 --> 00:29:19,520
Speaker 2: We really need an equals to.

609
00:29:19,600 --> 00:29:22,280
Speaker 1: We need another example of life out there in the

610
00:29:22,320 --> 00:29:24,760
Speaker 1: universe to tell us like, oh, wow, it's very similar.

611
00:29:24,760 --> 00:29:27,640
Speaker 1: Hours are wow, it's dramatically different. But right now we

612
00:29:27,720 --> 00:29:30,480
Speaker 1: just have an equals one, and we're extrapolating blindly.

613
00:29:30,960 --> 00:29:31,160
Speaker 5: You know.

614
00:29:31,280 --> 00:29:34,120
Speaker 3: I think maybe we should have called the show Daniel

615
00:29:34,160 --> 00:29:40,240
Speaker 3: and Kelly's not really explainable yet universe. But oh, that's

616
00:29:40,280 --> 00:29:43,040
Speaker 3: all right. We're enjoying ourselves, all right, So what's the

617
00:29:43,040 --> 00:29:45,040
Speaker 3: next thing that they want us to think about?

618
00:29:45,240 --> 00:29:47,080
Speaker 1: The next thing is to think about where you are

619
00:29:47,120 --> 00:29:49,120
Speaker 1: in the Solar System, right, So, say you have a

620
00:29:49,160 --> 00:29:52,760
Speaker 1: star where you are convinced Earth like life could evolve,

621
00:29:53,360 --> 00:29:55,479
Speaker 1: Then do you have a planet that's in the right region?

622
00:29:55,560 --> 00:29:58,360
Speaker 1: And so people talk a lot about this habitable zone.

623
00:29:58,520 --> 00:30:00,360
Speaker 1: You have to be close enough to the star for

624
00:30:00,440 --> 00:30:03,120
Speaker 1: water to melt, but not so close that water is

625
00:30:03,120 --> 00:30:05,400
Speaker 1: going to get turned into vapor and everything on the

626
00:30:05,400 --> 00:30:07,920
Speaker 1: planet is going to get fried. And again, this is

627
00:30:07,960 --> 00:30:11,640
Speaker 1: assuming that you have water based life, and so you

628
00:30:11,720 --> 00:30:14,200
Speaker 1: need liquid water on the surface, and like, we certainly

629
00:30:14,200 --> 00:30:17,040
Speaker 1: have water based life here on Earth, but it's also

630
00:30:17,240 --> 00:30:20,160
Speaker 1: not that hard to imagine life on a planet where

631
00:30:20,160 --> 00:30:21,960
Speaker 1: there isn't liquid water on the surface.

632
00:30:22,680 --> 00:30:27,040
Speaker 3: I disagree as a biologist, it's hard for me to

633
00:30:27,080 --> 00:30:30,520
Speaker 3: imagine life without water, but I think that's just because

634
00:30:31,320 --> 00:30:33,160
Speaker 3: this is the planet that I'm on, and this is

635
00:30:33,160 --> 00:30:36,880
Speaker 3: what I know, but questions like this, I waffle between thinking, well,

636
00:30:36,880 --> 00:30:38,720
Speaker 3: maybe it could be totally different than what we know,

637
00:30:38,880 --> 00:30:40,760
Speaker 3: and then thinking, okay, but still we have all these

638
00:30:40,800 --> 00:30:43,920
Speaker 3: different conditions on Earth and we're not seeing like life

639
00:30:43,960 --> 00:30:47,680
Speaker 3: evolving independently on our deserts. Like if it was that easy,

640
00:30:47,720 --> 00:30:50,400
Speaker 3: we'd expect an equals too on Earth for the origin

641
00:30:50,440 --> 00:30:52,600
Speaker 3: of life coming up in the desert, and so we

642
00:30:52,680 --> 00:30:53,040
Speaker 3: don't know.

643
00:30:53,520 --> 00:30:55,160
Speaker 1: Yeah, and that's actually a question I have. It's like,

644
00:30:55,200 --> 00:30:57,480
Speaker 1: how do we know that life didn't start multiple times

645
00:30:57,960 --> 00:31:01,800
Speaker 1: on Earth? That there aren't of that somewhere or history

646
00:31:01,800 --> 00:31:02,440
Speaker 1: of that somewhere.

647
00:31:02,680 --> 00:31:02,920
Speaker 2: You know.

648
00:31:03,000 --> 00:31:06,040
Speaker 1: Let me give you a counter example. What about life

649
00:31:06,160 --> 00:31:10,040
Speaker 1: forming on subsurface oceans. Say you have, for example, the

650
00:31:10,040 --> 00:31:13,160
Speaker 1: moon or of a gas giant, and it's frozen solid

651
00:31:13,240 --> 00:31:15,760
Speaker 1: on the surface because it's cold and far from the sun,

652
00:31:16,160 --> 00:31:19,680
Speaker 1: but there's enough pressure and enough tidal forces that internally

653
00:31:19,720 --> 00:31:22,400
Speaker 1: there's heat. And then you have a subsurface ocean. Why

654
00:31:22,440 --> 00:31:24,760
Speaker 1: can't you have life forming there? So it's still water,

655
00:31:24,840 --> 00:31:28,160
Speaker 1: but it's not liquid water on the surface, and technically

656
00:31:28,400 --> 00:31:30,400
Speaker 1: that's outside of these guys' habitable zone.

657
00:31:30,560 --> 00:31:33,400
Speaker 3: I would not be too surprised if we did find

658
00:31:33,440 --> 00:31:35,720
Speaker 3: life there. It would be really fun to have someone

659
00:31:35,760 --> 00:31:38,760
Speaker 3: on the show who studies extremophiles and see what their

660
00:31:38,800 --> 00:31:40,640
Speaker 3: take is on this stuff. But yeah, I guess I

661
00:31:40,640 --> 00:31:44,560
Speaker 3: wouldn't be surprised to find life on Mars like in

662
00:31:44,600 --> 00:31:46,920
Speaker 3: the caves, because it used to be a wet planet

663
00:31:46,960 --> 00:31:49,800
Speaker 3: and maybe bacteria might still be living under the surface

664
00:31:49,880 --> 00:31:52,400
Speaker 3: or something that looks like bacteria at Us or on

665
00:31:52,480 --> 00:31:54,040
Speaker 3: these subsurface oceans.

666
00:31:54,440 --> 00:31:57,080
Speaker 1: Yeah, I think the extremophiles are a really important lesson for.

667
00:31:57,000 --> 00:31:57,720
Speaker 2: Those of you who don't know.

668
00:31:57,760 --> 00:31:59,920
Speaker 1: These are examples of life that live in extreme can

669
00:32:01,040 --> 00:32:03,680
Speaker 1: And my wife is a microbiologist, and she basically tells

670
00:32:03,680 --> 00:32:06,400
Speaker 1: me it's impossible to ever make anything sterile because life

671
00:32:06,440 --> 00:32:08,960
Speaker 1: is everywhere and it always will be. And she tells

672
00:32:09,000 --> 00:32:12,120
Speaker 1: me these examples of like probes that we send up

673
00:32:12,120 --> 00:32:14,120
Speaker 1: into space, we try to make them sterile because we

674
00:32:14,120 --> 00:32:16,040
Speaker 1: don't want to like land on Mars and infect it

675
00:32:16,080 --> 00:32:19,080
Speaker 1: with Earth microbes and then later rediscover those microbes and

676
00:32:19,080 --> 00:32:21,720
Speaker 1: think we're finding Mars life. But every time we do,

677
00:32:21,800 --> 00:32:23,800
Speaker 1: we discover that there are some microbes that are gonna

678
00:32:23,960 --> 00:32:26,680
Speaker 1: be happy living in whatever conditions we put this probe in.

679
00:32:27,040 --> 00:32:29,200
Speaker 1: You know, they develop all these poison to kill microbes,

680
00:32:29,240 --> 00:32:31,520
Speaker 1: and then some microbe evolves to eat that poison and

681
00:32:31,560 --> 00:32:36,000
Speaker 1: it's like yum, thanks. And so it's basically impossible to

682
00:32:36,080 --> 00:32:38,360
Speaker 1: kill off life on Earth, which tells you that life

683
00:32:38,440 --> 00:32:41,480
Speaker 1: is pretty hardy and it might survive or even evolve

684
00:32:41,640 --> 00:32:44,560
Speaker 1: in crazy conditions. The other thing that's really going to

685
00:32:44,680 --> 00:32:47,120
Speaker 1: change your experience on the planet is not just are

686
00:32:47,160 --> 00:32:50,120
Speaker 1: you inhabitable zone, but what kind of star do you have?

687
00:32:50,640 --> 00:32:53,000
Speaker 1: Like do you have a star that's very stable, it's

688
00:32:53,000 --> 00:32:56,080
Speaker 1: always pumping out the same amount of energy all the time,

689
00:32:56,160 --> 00:32:58,720
Speaker 1: so that the habitable zone is constant, you're always in it.

690
00:32:59,080 --> 00:33:01,360
Speaker 1: Or you could also have a that's pretty variable. Some

691
00:33:01,440 --> 00:33:03,680
Speaker 1: stars out there get much brighter and then much dimmer,

692
00:33:03,720 --> 00:33:06,360
Speaker 1: and then much brighter and than much dimmer again. What

693
00:33:06,360 --> 00:33:09,800
Speaker 1: would it be like for life to evolve under those conditions?

694
00:33:10,200 --> 00:33:13,760
Speaker 1: You know, like Acephid, the famous variable stars that get

695
00:33:13,800 --> 00:33:17,440
Speaker 1: brighter and dimmer and very regular cycles. We use those

696
00:33:17,480 --> 00:33:19,680
Speaker 1: to learn about the distance ladder in the universe, how

697
00:33:19,720 --> 00:33:20,720
Speaker 1: far away things are.

698
00:33:21,320 --> 00:33:25,080
Speaker 3: I could imagine that spurring competition for plants at least,

699
00:33:25,120 --> 00:33:27,040
Speaker 3: you know, the trees that get the tallest are the

700
00:33:27,040 --> 00:33:28,880
Speaker 3: ones that are going to get the sunlight during those

701
00:33:28,920 --> 00:33:32,560
Speaker 3: dim light periods. I don't necessarily see that that would

702
00:33:32,600 --> 00:33:35,360
Speaker 3: have to kill life on the planet so much as

703
00:33:35,400 --> 00:33:38,200
Speaker 3: spur competition so that you're the one who succeeds during

704
00:33:38,240 --> 00:33:39,400
Speaker 3: the less good periods.

705
00:33:39,840 --> 00:33:40,640
Speaker 2: Yeah, exactly.

706
00:33:40,680 --> 00:33:44,240
Speaker 1: It might just create different conditions, and it might just

707
00:33:44,280 --> 00:33:47,320
Speaker 1: create a different kind of life. It's fascinating to think about.

708
00:33:47,640 --> 00:33:50,880
Speaker 1: The other component here is how many stars there are

709
00:33:51,000 --> 00:33:53,800
Speaker 1: in your solar system. We used to think of the

710
00:33:53,800 --> 00:33:57,360
Speaker 1: galaxies just a bunch of individual stars, and maybe under

711
00:33:57,360 --> 00:34:00,560
Speaker 1: exotic conditions you would have two stars and a system,

712
00:34:00,640 --> 00:34:03,600
Speaker 1: a fun topic for science fiction novels. But recently we've

713
00:34:03,680 --> 00:34:06,960
Speaker 1: learned that actually it's not uncommon to have two stars

714
00:34:06,960 --> 00:34:10,640
Speaker 1: in a system. That binary stars are very common, and

715
00:34:10,680 --> 00:34:13,640
Speaker 1: this is because of how stars form. Stars don't form

716
00:34:13,680 --> 00:34:16,399
Speaker 1: from like one gas cloud that collapses into a star.

717
00:34:16,840 --> 00:34:20,839
Speaker 1: Typically you have a huge star forming region that simultaneous

718
00:34:20,800 --> 00:34:23,000
Speaker 1: seeks is collapsing into a bunch of stars. So you

719
00:34:23,080 --> 00:34:26,919
Speaker 1: have like baby star neighbors and they're not isolated gravitationally,

720
00:34:27,000 --> 00:34:29,080
Speaker 1: they come together and they form a binary or even

721
00:34:29,080 --> 00:34:32,960
Speaker 1: a trinary system. And so something like fifty percent of

722
00:34:33,040 --> 00:34:35,160
Speaker 1: stars out there have a partner.

723
00:34:35,520 --> 00:34:38,080
Speaker 3: Oh wow, that probably would have been very surprising to Drake.

724
00:34:38,640 --> 00:34:40,960
Speaker 3: So the Drake's equation came out before we even landed

725
00:34:40,960 --> 00:34:43,200
Speaker 3: on the Moon. Yeah, and to think about how mind

726
00:34:43,200 --> 00:34:44,920
Speaker 3: blowing it would be to be able to get an

727
00:34:45,000 --> 00:34:46,840
Speaker 3: update on all of this stuff that we know. Okay,

728
00:34:46,880 --> 00:34:50,520
Speaker 3: so this is common. Why would it be harder to

729
00:34:50,640 --> 00:34:53,720
Speaker 3: evolve in a neighborhood with two sons. It's just twice

730
00:34:53,760 --> 00:34:57,440
Speaker 3: as much to photosynthesize.

731
00:34:58,280 --> 00:35:01,000
Speaker 1: Yeah, it also makes for less regular cycles though, Right,

732
00:35:01,239 --> 00:35:02,960
Speaker 1: you don't have the kind of cycles we have here

733
00:35:03,000 --> 00:35:05,520
Speaker 1: on Earth with seasons and days that are so regular.

734
00:35:06,040 --> 00:35:09,000
Speaker 1: You have a more chaotic system, right, you could be

735
00:35:09,120 --> 00:35:12,360
Speaker 1: like swapped between the two stars, or the stars themselves

736
00:35:12,400 --> 00:35:14,880
Speaker 1: could be fairly chaotic. So you might just not have

737
00:35:14,960 --> 00:35:17,680
Speaker 1: as regular a system. I don't know that that means

738
00:35:17,760 --> 00:35:20,480
Speaker 1: that life can't evolve. It might just have to be

739
00:35:20,560 --> 00:35:23,040
Speaker 1: more hearty and more adaptable, or just different from the

740
00:35:23,120 --> 00:35:25,480
Speaker 1: kind of life that we have. Again, I think this

741
00:35:25,560 --> 00:35:27,880
Speaker 1: is evidence that like these rare Earth guys are not

742
00:35:28,000 --> 00:35:30,719
Speaker 1: really thinking that far out of the box of.

743
00:35:30,680 --> 00:35:32,319
Speaker 2: Like what life could be like.

744
00:35:32,840 --> 00:35:36,640
Speaker 1: They're really just asking how common are our specific conditions

745
00:35:36,680 --> 00:35:39,080
Speaker 1: in the galaxy, and that could be very unusual but

746
00:35:39,120 --> 00:35:41,000
Speaker 1: that doesn't mean that there are no aliens.

747
00:35:41,239 --> 00:35:44,440
Speaker 3: Yeah, I can imagine the dynamics you just discussed just

748
00:35:44,600 --> 00:35:48,360
Speaker 3: driving life underground, for example, where things like temperature extremes

749
00:35:48,360 --> 00:35:50,759
Speaker 3: would be less pronounced and things would just kind of

750
00:35:50,760 --> 00:35:51,480
Speaker 3: be more stable.

751
00:35:51,520 --> 00:35:55,279
Speaker 1: In general, it basically means there's no California over there, right,

752
00:35:55,360 --> 00:35:58,400
Speaker 1: no place with like constant good weather all year long.

753
00:35:59,040 --> 00:36:01,640
Speaker 3: Well that's good, because that's so boring to constant good

754
00:36:01,640 --> 00:36:02,560
Speaker 3: weather all year long.

755
00:36:03,400 --> 00:36:05,640
Speaker 1: No, I want to meet the alien Californians. They're gonna

756
00:36:05,640 --> 00:36:08,239
Speaker 1: be the nicest ones. They're gonna be the chillest, you know.

757
00:36:08,719 --> 00:36:10,560
Speaker 2: I don't want to meet the grumpy Aliens.

758
00:36:10,600 --> 00:36:12,839
Speaker 1: They'll have to dig out of the snow and like

759
00:36:12,880 --> 00:36:14,439
Speaker 1: survive the serious heat.

760
00:36:15,200 --> 00:36:17,919
Speaker 3: You know, in Virginia, we have seasons and I love it.

761
00:36:18,480 --> 00:36:21,960
Speaker 3: And you know, not everybody in the California cities, you know,

762
00:36:22,040 --> 00:36:24,759
Speaker 3: some of them are a little snooty there.

763
00:36:25,280 --> 00:36:28,000
Speaker 1: Really, Oh my gosh, we're new snooty because we know

764
00:36:28,040 --> 00:36:30,279
Speaker 1: we live in the best place in the universe and

765
00:36:30,360 --> 00:36:31,480
Speaker 1: we're not shy to say it.

766
00:36:32,440 --> 00:36:34,080
Speaker 3: I think Virginia is more beautiful.

767
00:36:34,239 --> 00:36:37,080
Speaker 1: I said it all right right in if you have

768
00:36:37,120 --> 00:36:39,439
Speaker 1: an opinion about that, and whether aliens are more likely

769
00:36:39,640 --> 00:36:42,239
Speaker 1: to sit down in California or Virginia when they come.

770
00:36:42,800 --> 00:36:46,319
Speaker 3: Virginia is so much better come to Virginia Aliens. All right,

771
00:36:46,360 --> 00:37:06,160
Speaker 3: let's take a break and then we'll get back on track. So, Daniel,

772
00:37:06,239 --> 00:37:10,279
Speaker 3: what was the next criteria that Brownlee and Ward wanted

773
00:37:10,360 --> 00:37:11,279
Speaker 3: us to think about?

774
00:37:11,600 --> 00:37:14,200
Speaker 1: They wanted us to think about not just where you

775
00:37:14,280 --> 00:37:17,160
Speaker 1: are around the star, but what other planets there are

776
00:37:17,440 --> 00:37:20,960
Speaker 1: and whether that's an important part of life evolving. They

777
00:37:21,080 --> 00:37:23,520
Speaker 1: argue that the reason life evolved on Earth is not

778
00:37:23,600 --> 00:37:26,080
Speaker 1: just because the Earth is an in habitable zone where

779
00:37:26,120 --> 00:37:28,480
Speaker 1: water can be liquid on the surface and therefore you

780
00:37:28,520 --> 00:37:31,080
Speaker 1: can have a California, which we all know is super important,

781
00:37:31,560 --> 00:37:33,960
Speaker 1: but that the other planets in our Solar system have

782
00:37:34,040 --> 00:37:37,680
Speaker 1: played a big role. For example, having a big cousin

783
00:37:37,800 --> 00:37:41,120
Speaker 1: like Jupiter out in the outer Solar System might be

784
00:37:41,160 --> 00:37:44,319
Speaker 1: shielding us from comets. So again, they're like, really trying

785
00:37:44,320 --> 00:37:46,040
Speaker 1: to create a situation where you don't get hit by

786
00:37:46,040 --> 00:37:47,799
Speaker 1: comments a lot. I know you're a big fan of

787
00:37:47,880 --> 00:37:51,520
Speaker 1: life evolving under multiple cometary impacts.

788
00:37:51,160 --> 00:37:53,760
Speaker 3: But life is hard, man. You gotta be able to survive.

789
00:37:55,600 --> 00:37:57,839
Speaker 1: Is that what you teach your kids you're like, hey, kids,

790
00:37:57,880 --> 00:37:59,000
Speaker 1: asteroids could hit any day.

791
00:37:59,120 --> 00:37:59,640
Speaker 2: Check the weather.

792
00:38:00,080 --> 00:38:02,960
Speaker 3: As you know from our prior interactions, I try to

793
00:38:02,960 --> 00:38:05,880
Speaker 3: not make my kids lives filled with existential dread, but

794
00:38:05,960 --> 00:38:08,319
Speaker 3: I do try to prepare them for difficult situations.

795
00:38:08,600 --> 00:38:10,600
Speaker 2: That's a difficult line to walk there, Kelly, I'm not

796
00:38:10,600 --> 00:38:11,319
Speaker 2: sure you're doing it.

797
00:38:13,160 --> 00:38:14,160
Speaker 3: Thanks for critiquing my.

798
00:38:16,000 --> 00:38:17,799
Speaker 1: Yeah, exactly, I'm gonna have to talk to your kids

799
00:38:17,800 --> 00:38:20,720
Speaker 1: and let them know that you're actually pro asteroid impact.

800
00:38:21,840 --> 00:38:23,680
Speaker 3: I'm not going to let you talk to my kids,

801
00:38:25,040 --> 00:38:25,600
Speaker 3: all right.

802
00:38:25,680 --> 00:38:28,319
Speaker 1: Fair enough, I wouldn't either anyway. The idea is that

803
00:38:28,400 --> 00:38:31,640
Speaker 1: Jupiter's out there, and when comments do fall towards the

804
00:38:31,640 --> 00:38:35,520
Speaker 1: Inner Solar System, maybe it's acting like a celestial vacuum cleaner.

805
00:38:35,840 --> 00:38:38,840
Speaker 1: It's like blocking for us, you know. It's making sure

806
00:38:38,880 --> 00:38:41,680
Speaker 1: that these things are not hitting the Earth. It's making

807
00:38:41,719 --> 00:38:44,600
Speaker 1: the Inner Solar System like a little walled garden where

808
00:38:44,640 --> 00:38:47,400
Speaker 1: life is free to evolve while it's still vulnerable.

809
00:38:47,800 --> 00:38:50,440
Speaker 3: All right, Well, so we've already talked about how I

810
00:38:50,440 --> 00:38:54,360
Speaker 3: don't necessarily think asteroids are a showstopper, But how common

811
00:38:54,560 --> 00:38:58,560
Speaker 3: is it for other systems to have a Jupiter to

812
00:38:58,680 --> 00:39:00,640
Speaker 3: act as the celestial vacus and cleaner.

813
00:39:01,040 --> 00:39:03,520
Speaker 1: So we actually really don't know the answer to that question,

814
00:39:03,960 --> 00:39:05,920
Speaker 1: and it's one where the answer has been changing a

815
00:39:06,000 --> 00:39:08,440
Speaker 1: lot in the last few years. When we first developed

816
00:39:08,440 --> 00:39:11,719
Speaker 1: the ability to see planets around other stars, it was

817
00:39:11,760 --> 00:39:14,840
Speaker 1: a huge moment, right because we'd only ever seen planets

818
00:39:14,880 --> 00:39:17,440
Speaker 1: around our stars, so we didn't know how common is

819
00:39:17,480 --> 00:39:19,880
Speaker 1: it to have planets at all, and it is our

820
00:39:19,960 --> 00:39:23,440
Speaker 1: arrangement common or totally unusual. But the first planets we

821
00:39:23,480 --> 00:39:26,480
Speaker 1: could see were planets that were really big, and planets

822
00:39:26,480 --> 00:39:29,080
Speaker 1: that were really close to their star, And that's because

823
00:39:29,080 --> 00:39:31,520
Speaker 1: we were seeing the effects of those planets tugging on

824
00:39:31,640 --> 00:39:34,440
Speaker 1: their stars, like the gravity of the planet wiggling the

825
00:39:34,480 --> 00:39:36,759
Speaker 1: star a little bit. And later on we were seeing

826
00:39:36,800 --> 00:39:39,560
Speaker 1: planets pass in front of their stars, making like little

827
00:39:39,600 --> 00:39:43,400
Speaker 1: mini planet eclipses. Both of those are really good for

828
00:39:43,480 --> 00:39:45,920
Speaker 1: seeing planets that are big and close to their star,

829
00:39:46,160 --> 00:39:48,960
Speaker 1: and really bad at seeing anything else. So of course,

830
00:39:49,360 --> 00:39:53,400
Speaker 1: first planets we discover are hot jupiters, big planets close

831
00:39:53,440 --> 00:39:55,879
Speaker 1: to their star. So then everybody thought, oh my gosh, wow,

832
00:39:55,960 --> 00:39:58,080
Speaker 1: maybe the universe was filled with hot jupiters, And then

833
00:39:58,120 --> 00:40:00,520
Speaker 1: folks really well or maybe that's all we can and see,

834
00:40:00,719 --> 00:40:02,880
Speaker 1: and there's a bunch of invisible planets out there that

835
00:40:02,920 --> 00:40:05,399
Speaker 1: we don't know about. But it made people think really

836
00:40:05,480 --> 00:40:07,879
Speaker 1: carefully about the history of our own Solar system, because

837
00:40:07,880 --> 00:40:10,680
Speaker 1: they're like, well, if hot jupiters are really common, why

838
00:40:10,719 --> 00:40:13,360
Speaker 1: don't we have one. Why is our Jupiter so cold?

839
00:40:13,400 --> 00:40:16,680
Speaker 1: It's so far out in the Solar System. And that

840
00:40:16,800 --> 00:40:19,520
Speaker 1: inspired a lot of really interesting theory about like the

841
00:40:19,560 --> 00:40:24,120
Speaker 1: origins of the arrangements of our planets. And one fascinating

842
00:40:24,160 --> 00:40:26,480
Speaker 1: theory is that the typical thing is for a gas

843
00:40:26,480 --> 00:40:29,000
Speaker 1: giant to form in the outer Solar System, it has

844
00:40:29,040 --> 00:40:30,959
Speaker 1: to be far out there so it can grab enough

845
00:40:31,000 --> 00:40:33,319
Speaker 1: gas because the Sun tends to grab all the gas

846
00:40:33,320 --> 00:40:36,200
Speaker 1: in the inner Solar System. But then they typically fall

847
00:40:36,239 --> 00:40:39,800
Speaker 1: into the inner Solar System because of chaos and dynamical

848
00:40:39,880 --> 00:40:43,160
Speaker 1: friction and whatever. They migrate inwards. And so that's what

849
00:40:43,200 --> 00:40:46,719
Speaker 1: we're seeing out there in other Solar systems, jupiters that

850
00:40:46,840 --> 00:40:49,880
Speaker 1: form far out and then work their way in and

851
00:40:50,080 --> 00:40:52,720
Speaker 1: eventually those planets are going to plummet into their stars.

852
00:40:53,000 --> 00:40:55,960
Speaker 1: They're not really stable. But that's not what we have here.

853
00:40:56,360 --> 00:40:59,239
Speaker 1: And so the theory is that our Jupiter formed and

854
00:40:59,280 --> 00:41:03,400
Speaker 1: our Saturn formed and some now lost other gas giant

855
00:41:03,440 --> 00:41:06,839
Speaker 1: in our Solar system formed and they migrated in as

856
00:41:06,880 --> 00:41:10,360
Speaker 1: you typically expect. But then some chaotic interaction happened and

857
00:41:10,440 --> 00:41:12,920
Speaker 1: Jupiter and Saturn got kicked to the outer Solar System

858
00:41:13,200 --> 00:41:16,760
Speaker 1: and the now lost gas giant ejected from the Solar System.

859
00:41:17,160 --> 00:41:19,879
Speaker 1: So we have a missing planet that got like rejected

860
00:41:20,000 --> 00:41:22,960
Speaker 1: from the Solar System is now out there floating alone

861
00:41:23,080 --> 00:41:23,640
Speaker 1: in space.

862
00:41:24,120 --> 00:41:26,560
Speaker 3: Wow. Would we expect to be able to find it?

863
00:41:26,640 --> 00:41:28,280
Speaker 3: Or could it have gotten pretty far away?

864
00:41:28,760 --> 00:41:30,200
Speaker 2: It could have gotten pretty far away.

865
00:41:30,480 --> 00:41:32,279
Speaker 1: And these days we know that there are lots and

866
00:41:32,280 --> 00:41:34,920
Speaker 1: lots of these planets, they're called rogue planets that have

867
00:41:34,960 --> 00:41:37,760
Speaker 1: been ejected from their Solar system. So like our pretty

868
00:41:37,760 --> 00:41:41,000
Speaker 1: picture of planets having nice circular orbits around their stars,

869
00:41:41,280 --> 00:41:43,080
Speaker 1: it's kind of an ancient idea, and now we know

870
00:41:43,160 --> 00:41:46,560
Speaker 1: that like Solar system dynamics are pretty chaotic. It's not

871
00:41:46,600 --> 00:41:48,960
Speaker 1: that unusual to lose a planet. In fact, it's kind

872
00:41:48,960 --> 00:41:51,239
Speaker 1: of amazing if you don't, if you can onto a

873
00:41:51,280 --> 00:41:54,560
Speaker 1: planet for billions of years. And so anyway, that's how

874
00:41:54,560 --> 00:41:57,080
Speaker 1: we ended up with this Jupiter in the outer Solar System,

875
00:41:57,200 --> 00:41:59,839
Speaker 1: sort of protecting us that might be unusual. It could

876
00:41:59,880 --> 00:42:02,720
Speaker 1: be that typically the big giants just end up falling

877
00:42:02,719 --> 00:42:05,360
Speaker 1: into their stars, and that's what we're seeing out there

878
00:42:05,560 --> 00:42:07,960
Speaker 1: in other solar systems. But this is a question where

879
00:42:07,960 --> 00:42:10,799
Speaker 1: we're learning new stuff every day because we've only seen

880
00:42:10,840 --> 00:42:13,799
Speaker 1: a few thousand exoplanets and we're rapidly seeing more and

881
00:42:13,840 --> 00:42:16,719
Speaker 1: more and more, and so the picture is changing constantly,

882
00:42:16,719 --> 00:42:19,040
Speaker 1: which is my favorite thing in science when we're like

883
00:42:19,080 --> 00:42:21,160
Speaker 1: our eyeballs are opening up and we're learning more and

884
00:42:21,160 --> 00:42:22,080
Speaker 1: more about the universe.

885
00:42:22,360 --> 00:42:25,000
Speaker 3: Yeah, no, it's exciting. Also, I think someone should start

886
00:42:25,000 --> 00:42:27,160
Speaker 3: a band hot Jupiter and the Road planets.

887
00:42:28,719 --> 00:42:30,680
Speaker 1: And there are also people who make the opposite argument.

888
00:42:30,719 --> 00:42:33,719
Speaker 1: They say that actually having a Jupiter in your solar

889
00:42:33,760 --> 00:42:37,839
Speaker 1: system is not good for reducing impacts, that actually having

890
00:42:37,880 --> 00:42:40,960
Speaker 1: a Jupiter could cause impacts because it makes these gravitational

891
00:42:40,960 --> 00:42:44,040
Speaker 1: instabilities like tugs on stuff, and it might actually pull

892
00:42:44,040 --> 00:42:46,919
Speaker 1: stuff towards the Earth. There was a case in our

893
00:42:47,000 --> 00:42:50,359
Speaker 1: solar system in seventeen seventy there's a near miss when

894
00:42:50,400 --> 00:42:52,600
Speaker 1: a comet came really close to the Earth. It was

895
00:42:52,640 --> 00:42:56,080
Speaker 1: called Lexel's comet, and you can reconstruct its path and

896
00:42:56,080 --> 00:42:59,480
Speaker 1: they're pretty sure that it was Jupiter's fault that it

897
00:42:59,520 --> 00:43:01,560
Speaker 1: was not going to anywhere near the Earth, and then

898
00:43:01,680 --> 00:43:04,759
Speaker 1: Jupiter tugged on it and basically aimed it right at

899
00:43:04,760 --> 00:43:07,400
Speaker 1: the Earth. It was a really close call. And so

900
00:43:07,520 --> 00:43:10,759
Speaker 1: there's examples there were like, yeah, Jupiter can save you,

901
00:43:10,800 --> 00:43:13,959
Speaker 1: but Jupiter could also, you know, send something bad your way.

902
00:43:14,440 --> 00:43:16,799
Speaker 3: So how would you figure out if, on balance it

903
00:43:16,840 --> 00:43:19,080
Speaker 3: was better to have a Jupiter. I guess it would

904
00:43:19,120 --> 00:43:23,000
Speaker 3: depend on so many different factors. Then, with what we know,

905
00:43:23,040 --> 00:43:25,520
Speaker 3: you couldn't come down in this argument one way or another. Probably.

906
00:43:25,760 --> 00:43:28,160
Speaker 1: Yeah, it's a really chaotic thing, right If you start

907
00:43:28,160 --> 00:43:30,399
Speaker 1: with the solar system, you don't really know whether having

908
00:43:30,400 --> 00:43:32,160
Speaker 1: a Jupiter would be better or worse. You can't sit

909
00:43:32,200 --> 00:43:34,239
Speaker 1: down and calculate it. All you can do is run

910
00:43:34,280 --> 00:43:37,239
Speaker 1: a bunch of simulations, and those simulations depend on the

911
00:43:37,280 --> 00:43:40,040
Speaker 1: initial conditions, like what is the distribution of gas, and

912
00:43:40,080 --> 00:43:41,919
Speaker 1: where are the metals and where the rock and the ice.

913
00:43:42,320 --> 00:43:44,960
Speaker 1: Very sensitive to all those details, and we don't know

914
00:43:45,040 --> 00:43:47,920
Speaker 1: how most solar systems start, and so people run a

915
00:43:47,960 --> 00:43:50,560
Speaker 1: lot of simulations, but everybody starts from different places and

916
00:43:50,560 --> 00:43:53,520
Speaker 1: gets different answers, and so it's a big mystery.

917
00:43:53,600 --> 00:43:53,880
Speaker 2: Right now.

918
00:43:53,920 --> 00:43:55,920
Speaker 1: We just really don't know the answer to this question.

919
00:43:56,400 --> 00:43:59,480
Speaker 1: So in the rare Earth hypothesis, they suggest our Jupiter

920
00:43:59,560 --> 00:44:02,440
Speaker 1: is rare and it was really important, But we actually

921
00:44:02,480 --> 00:44:04,400
Speaker 1: don't know how rare it is, and we don't know

922
00:44:04,520 --> 00:44:07,080
Speaker 1: it's important or not. So it's really much more of

923
00:44:07,120 --> 00:44:08,120
Speaker 1: an open question.

924
00:44:08,440 --> 00:44:10,839
Speaker 3: All right, So what's the next level that we need

925
00:44:10,880 --> 00:44:11,560
Speaker 3: to be considering.

926
00:44:12,200 --> 00:44:14,320
Speaker 1: The next thing is about the size of our planet,

927
00:44:14,760 --> 00:44:18,000
Speaker 1: Like rocky planets have to be the right size, they argue,

928
00:44:18,000 --> 00:44:20,200
Speaker 1: in order to have life on them. And you know,

929
00:44:20,320 --> 00:44:22,160
Speaker 1: we have some examples of that, like if you look

930
00:44:22,160 --> 00:44:25,319
Speaker 1: at Mars, it's basically an the habitable zone, but it's

931
00:44:25,400 --> 00:44:28,040
Speaker 1: kind of small. It's lots smaller than Earth, and it's

932
00:44:28,080 --> 00:44:30,680
Speaker 1: so small that it doesn't have much of an atmosphere.

933
00:44:30,719 --> 00:44:33,680
Speaker 1: It's like one percent of the atmosphere of Earth because

934
00:44:33,719 --> 00:44:35,759
Speaker 1: it doesn't have the gravity to hold onto it the

935
00:44:35,800 --> 00:44:38,279
Speaker 1: way the Moon doesn't, for example. So you can't have

936
00:44:38,400 --> 00:44:41,640
Speaker 1: Earth like life evolving on Mars the way it is now.

937
00:44:42,320 --> 00:44:45,040
Speaker 1: And if you have too much stuff, you're over dense.

938
00:44:45,239 --> 00:44:47,239
Speaker 1: Then you can have a really dense atmosphere the way

939
00:44:47,360 --> 00:44:50,280
Speaker 1: like Venus does. You know, their atmosphere is like something

940
00:44:50,280 --> 00:44:52,880
Speaker 1: you couldn't even breathe. It's like soup, right, It's also

941
00:44:52,960 --> 00:44:56,320
Speaker 1: like sulphuric acid. But it's very different from the conditions

942
00:44:56,360 --> 00:44:58,600
Speaker 1: on Earth. And so they argue that like having a

943
00:44:58,680 --> 00:45:02,239
Speaker 1: rocky planet with just right mass, to have an atmosphere

944
00:45:02,360 --> 00:45:05,319
Speaker 1: like ours so we can all enjoy breezy sunny days

945
00:45:05,320 --> 00:45:07,400
Speaker 1: in California is pretty unusual.

946
00:45:07,840 --> 00:45:08,040
Speaker 6: You know.

947
00:45:08,120 --> 00:45:11,239
Speaker 3: The breezy sunny days in Virginia are nice. Also, there's

948
00:45:11,280 --> 00:45:13,880
Speaker 3: maybe a little more humidity. But the deal with needing

949
00:45:13,920 --> 00:45:16,480
Speaker 3: an atmosphere is that what it protects you from radiation,

950
00:45:16,719 --> 00:45:21,200
Speaker 3: it moderates temperature swings. Are those the main reasons why

951
00:45:21,200 --> 00:45:22,160
Speaker 3: you need an atmosphere.

952
00:45:22,480 --> 00:45:25,080
Speaker 1: You need an atmosphere absolutely for those reasons. And if

953
00:45:25,160 --> 00:45:28,440
Speaker 1: you think oxygen is important for all the biochemistry of Earth,

954
00:45:28,880 --> 00:45:30,520
Speaker 1: then you need to be able to hang on to

955
00:45:30,640 --> 00:45:33,319
Speaker 1: the oxygen when it's produced. You know, oxygen is not

956
00:45:33,440 --> 00:45:35,560
Speaker 1: something that we had in our atmosphere early on. It

957
00:45:35,560 --> 00:45:38,520
Speaker 1: took a long long time for oxygen to be produced

958
00:45:38,800 --> 00:45:42,080
Speaker 1: by early life, so that more complex life that used

959
00:45:42,120 --> 00:45:44,680
Speaker 1: oxygen it could be very efficient, could evolve.

960
00:45:44,719 --> 00:45:46,640
Speaker 2: I'm sure you know more about that than I do.

961
00:45:47,080 --> 00:45:48,120
Speaker 2: And you have to be able.

962
00:45:47,960 --> 00:45:49,560
Speaker 1: To hold onto that oxygen, right, if it I'll just

963
00:45:49,680 --> 00:45:52,239
Speaker 1: drift it out into space. Then you wouldn't be able

964
00:45:52,280 --> 00:45:54,640
Speaker 1: to use it for more complex life.

965
00:45:54,920 --> 00:45:57,960
Speaker 3: So right now we probably don't know, like even for

966
00:45:58,080 --> 00:46:01,800
Speaker 3: Earth like life to evolve, does fifty to one hundred

967
00:46:01,800 --> 00:46:06,120
Speaker 3: and fifty percent of Earth's atmosphere work? Like, could life

968
00:46:06,120 --> 00:46:08,680
Speaker 3: still have evolved if we had, you know, fifty percent

969
00:46:08,719 --> 00:46:11,040
Speaker 3: the atmosphere we have? Now we don't know that.

970
00:46:11,680 --> 00:46:14,120
Speaker 2: I assume we don't know anything about that.

971
00:46:14,200 --> 00:46:16,839
Speaker 1: Yeah, Like we still have really no idea about how

972
00:46:16,920 --> 00:46:19,600
Speaker 1: life started on Earth or what the crucial points were,

973
00:46:19,760 --> 00:46:21,399
Speaker 1: how many times it started on Earth.

974
00:46:21,440 --> 00:46:23,040
Speaker 2: As we talked about earlier.

975
00:46:23,000 --> 00:46:25,280
Speaker 1: This is the place where we're really in the dark.

976
00:46:25,719 --> 00:46:27,600
Speaker 1: And so I don't want to be too negative about it,

977
00:46:27,600 --> 00:46:29,839
Speaker 1: because I think it is useful just try to think

978
00:46:29,840 --> 00:46:32,000
Speaker 1: about these things and to take first attempts and then

979
00:46:32,239 --> 00:46:34,760
Speaker 1: the next generation of scientists coming along being like, okay,

980
00:46:34,840 --> 00:46:37,600
Speaker 1: reasonable first step, but actually, and you know that's the

981
00:46:37,640 --> 00:46:40,440
Speaker 1: way progress is made. It's incremental. But I also really

982
00:46:40,440 --> 00:46:44,200
Speaker 1: think we really haven't gotten anywhere this question, because as

983
00:46:44,239 --> 00:46:47,279
Speaker 1: you say, twice as much atmosphere might be fine, or

984
00:46:47,480 --> 00:46:50,120
Speaker 1: maybe it's even better if you have a denser atmosphere.

985
00:46:50,480 --> 00:46:52,960
Speaker 1: Just because no life evolved on Venus as far as

986
00:46:52,960 --> 00:46:55,640
Speaker 1: we know, doesn't mean that life can't evolve on Venus.

987
00:46:55,680 --> 00:46:58,160
Speaker 1: Like planets, it might be a little different. It might

988
00:46:58,239 --> 00:47:00,800
Speaker 1: enjoy the humidity, and it might like to lie and in Virginia.

989
00:47:01,160 --> 00:47:03,120
Speaker 1: But you know, that's okay, I'm open minded.

990
00:47:04,920 --> 00:47:06,399
Speaker 3: I mean, it would be so awesome if we could

991
00:47:06,400 --> 00:47:10,200
Speaker 3: just find microbial life somewhere else in the Solar System

992
00:47:10,239 --> 00:47:12,320
Speaker 3: to give us like a handle on this kind of stuff.

993
00:47:12,360 --> 00:47:14,840
Speaker 3: But all right, so say that you are on a

994
00:47:14,880 --> 00:47:18,400
Speaker 3: planet that's the right size and has the right atmosphere,

995
00:47:19,080 --> 00:47:20,279
Speaker 3: are there other criteria?

996
00:47:20,960 --> 00:47:21,759
Speaker 2: They argue in.

997
00:47:21,719 --> 00:47:24,719
Speaker 1: The book that there's an internal criteria that having a

998
00:47:24,760 --> 00:47:29,440
Speaker 1: planet with internal dynamics like lava or magma flow under

999
00:47:29,440 --> 00:47:33,920
Speaker 1: the mantle, having plate tectonics and volcanic activity is crucial

1000
00:47:34,320 --> 00:47:37,160
Speaker 1: for creating the conditions for life to evolve on Earth.

1001
00:47:37,640 --> 00:47:40,640
Speaker 1: And I think the argument is that like plate tectonics

1002
00:47:41,000 --> 00:47:44,239
Speaker 1: lead to like continental drift, and so you take populations

1003
00:47:44,280 --> 00:47:47,120
Speaker 1: and like separate them and then you can protect them.

1004
00:47:47,239 --> 00:47:49,680
Speaker 1: You get more diversity rather than like if you have

1005
00:47:49,719 --> 00:47:51,919
Speaker 1: a static planet. And it's just like when one big

1006
00:47:51,920 --> 00:47:55,000
Speaker 1: British competition for life, you might have like one winner

1007
00:47:55,280 --> 00:47:57,640
Speaker 1: instead of like a bunch of different populations and different

1008
00:47:57,680 --> 00:48:01,520
Speaker 1: ecosystems with multiple winners. That's the argument. I don't know

1009
00:48:01,520 --> 00:48:04,319
Speaker 1: how effective that argument is. It's more just like a, hey,

1010
00:48:04,360 --> 00:48:07,000
Speaker 1: this seem to have played an important role in the

1011
00:48:07,040 --> 00:48:11,040
Speaker 1: way that life evolved on Earth. Maybe it's also important everywhere.

1012
00:48:11,200 --> 00:48:12,759
Speaker 1: What do you think about that as a biologist.

1013
00:48:13,080 --> 00:48:17,600
Speaker 3: I mean, certainly plate tectonics has had interesting implications for

1014
00:48:17,640 --> 00:48:21,000
Speaker 3: biodiversity on Earth, and so you know, you have gotten

1015
00:48:21,160 --> 00:48:24,480
Speaker 3: species that look very similar on different continents that do

1016
00:48:24,640 --> 00:48:28,160
Speaker 3: have you know, shared evolutionary history, and now they look

1017
00:48:28,200 --> 00:48:31,240
Speaker 3: and act very different, and so that diversity is interesting.

1018
00:48:31,600 --> 00:48:34,200
Speaker 3: But you know, we didn't, for example, see one winner

1019
00:48:34,400 --> 00:48:37,600
Speaker 3: on each of the different continents. You see lots of

1020
00:48:37,640 --> 00:48:41,359
Speaker 3: different solutions to problems. And I would imagine tectonics would

1021
00:48:41,360 --> 00:48:45,400
Speaker 3: be helpful for increasing biodiversity, but not necessarily needed, especially

1022
00:48:45,440 --> 00:48:48,279
Speaker 3: if you have other things in the environment that are

1023
00:48:48,560 --> 00:48:51,200
Speaker 3: problems that need to be solved that drive adaptations.

1024
00:48:51,920 --> 00:48:54,080
Speaker 1: Yeah, and people have tried to actually answer this question,

1025
00:48:54,600 --> 00:48:57,680
Speaker 1: and there are some recent studies that show that plate

1026
00:48:57,719 --> 00:49:00,760
Speaker 1: tectonics are sort of episodic that you have like times

1027
00:49:00,800 --> 00:49:03,040
Speaker 1: when there's a lot of activity in times when it's stagnant,

1028
00:49:03,440 --> 00:49:05,800
Speaker 1: and some of the crucial developments in the evolution of

1029
00:49:05,840 --> 00:49:07,719
Speaker 1: life as we know it may come during those like

1030
00:49:07,760 --> 00:49:11,080
Speaker 1: stagnant periods when things are more chill. So again, like

1031
00:49:11,080 --> 00:49:12,839
Speaker 1: with everything on this topic, you could see it going

1032
00:49:12,880 --> 00:49:15,799
Speaker 1: both ways. You could like convince yourself of a or

1033
00:49:15,840 --> 00:49:18,160
Speaker 1: not about equally well.

1034
00:49:19,600 --> 00:49:21,239
Speaker 3: But again I think that you noted. It gives us

1035
00:49:21,280 --> 00:49:23,239
Speaker 3: interesting things that we should try to drill down and

1036
00:49:23,320 --> 00:49:25,879
Speaker 3: understand better and sort of focuses where we might want

1037
00:49:25,880 --> 00:49:27,320
Speaker 3: to do research in the future.

1038
00:49:27,480 --> 00:49:30,200
Speaker 1: Yeah, and one thing we've learned is that volcanic activity

1039
00:49:30,239 --> 00:49:32,400
Speaker 1: and internal motion in a planet might not be that

1040
00:49:32,520 --> 00:49:34,600
Speaker 1: rare we thought for a long time. For example, Earth

1041
00:49:34,719 --> 00:49:37,080
Speaker 1: was the only place in the Solar System that had

1042
00:49:37,160 --> 00:49:40,560
Speaker 1: volcanoes and had internal tectonics. But now we know that

1043
00:49:40,640 --> 00:49:43,200
Speaker 1: like volcanoes are everywhere in the Solar System, they're on

1044
00:49:43,239 --> 00:49:45,600
Speaker 1: some of those moons that we talked about. We think

1045
00:49:45,640 --> 00:49:49,439
Speaker 1: that Pluto had volcanoes for a while. The Moon used

1046
00:49:49,440 --> 00:49:52,240
Speaker 1: to have internal activity before it cooled, and so did Mars,

1047
00:49:52,719 --> 00:49:55,040
Speaker 1: and so it might not even be as rare as

1048
00:49:55,080 --> 00:49:58,120
Speaker 1: people thought when this book was written. So maybe it

1049
00:49:58,200 --> 00:50:00,319
Speaker 1: is crucial for life to form, but that doesn't that

1050
00:50:00,360 --> 00:50:02,560
Speaker 1: life is rare, because it might be the plate tectonics

1051
00:50:02,560 --> 00:50:03,160
Speaker 1: are everywhere.

1052
00:50:03,320 --> 00:50:04,440
Speaker 3: Yeah, okay enough.

1053
00:50:04,840 --> 00:50:06,800
Speaker 1: One of the last bits they talk about is having

1054
00:50:06,840 --> 00:50:09,719
Speaker 1: a moon. You know, we have a big, fat moon

1055
00:50:09,719 --> 00:50:12,160
Speaker 1: in the sky, which is kind of cool and beautiful,

1056
00:50:12,480 --> 00:50:15,719
Speaker 1: even if you're in Virginia. But people speculate about the

1057
00:50:15,800 --> 00:50:18,560
Speaker 1: role of the moon in the evolution of life on Earth.

1058
00:50:18,880 --> 00:50:21,120
Speaker 1: Having a big moon does seem a little bit unusual,

1059
00:50:21,200 --> 00:50:24,000
Speaker 1: like in our Solar system. There are not other planets

1060
00:50:24,000 --> 00:50:27,000
Speaker 1: that have just one big moon. And having a big

1061
00:50:27,080 --> 00:50:29,960
Speaker 1: moon like this makes for tidal effects. You know, the

1062
00:50:30,000 --> 00:50:32,240
Speaker 1: moon pulls on the ocean and you get high tide

1063
00:50:32,239 --> 00:50:35,920
Speaker 1: and low tide. It's really fascinating physics. And there's this

1064
00:50:36,000 --> 00:50:39,200
Speaker 1: theory I've heard before that having these tides helps life

1065
00:50:39,239 --> 00:50:42,560
Speaker 1: evolve because you get like the brackish conditions between the

1066
00:50:42,560 --> 00:50:45,279
Speaker 1: salt water and the fresh water. You get all the

1067
00:50:45,320 --> 00:50:49,320
Speaker 1: sloshing around which mixes up the amino acids, and imagining

1068
00:50:49,360 --> 00:50:52,920
Speaker 1: some like bubbling cauldron of prebiotic soup, and you might

1069
00:50:52,960 --> 00:50:56,200
Speaker 1: get life evolving more easily if you're stirring that cauldron

1070
00:50:56,280 --> 00:50:58,640
Speaker 1: rather than just like letting it sit and be stagnant.

1071
00:50:59,280 --> 00:51:01,560
Speaker 1: But again, you're sort of talking yourself into this argument.

1072
00:51:01,600 --> 00:51:02,480
Speaker 1: What do you think about that?

1073
00:51:02,719 --> 00:51:05,000
Speaker 3: Is there no other way that stirring would happen? Like,

1074
00:51:05,000 --> 00:51:07,960
Speaker 3: wouldn't you still get rivers going into the sea and

1075
00:51:08,120 --> 00:51:12,880
Speaker 3: do Coriolis effects influence the way water sort of moves

1076
00:51:12,920 --> 00:51:15,799
Speaker 3: around the Earth. It wouldn't be as extreme or as

1077
00:51:15,840 --> 00:51:18,799
Speaker 3: fun to surf on, But I think you could still

1078
00:51:18,800 --> 00:51:19,560
Speaker 3: get it to happen.

1079
00:51:20,520 --> 00:51:21,760
Speaker 2: How's the surfing in Virginia?

1080
00:51:21,760 --> 00:51:23,799
Speaker 3: By the way, I am not cool enough to answer

1081
00:51:23,840 --> 00:51:26,800
Speaker 3: that question. Well, we have beaches and they're beautiful.

1082
00:51:26,680 --> 00:51:29,120
Speaker 2: Okay, I believe you. I believe you. I don't know

1083
00:51:29,160 --> 00:51:29,879
Speaker 2: the answer that question.

1084
00:51:29,960 --> 00:51:31,960
Speaker 1: I don't know that anybody knows the answer that question

1085
00:51:32,120 --> 00:51:34,600
Speaker 1: until we make the discovery you talked about, which is like, fine,

1086
00:51:34,640 --> 00:51:38,040
Speaker 1: microbe somewhere else and learn about the history there. But

1087
00:51:38,200 --> 00:51:40,239
Speaker 1: you know, it's easy to point to these things which

1088
00:51:40,280 --> 00:51:42,640
Speaker 1: affected life on Earth and say, oh, this must have

1089
00:51:42,680 --> 00:51:45,719
Speaker 1: been crucial and without it life couldn't have evolved or

1090
00:51:45,760 --> 00:51:48,520
Speaker 1: would be so dramatically different. We wouldn't even recognize it.

1091
00:51:48,920 --> 00:51:49,080
Speaker 2: You know.

1092
00:51:49,080 --> 00:51:51,839
Speaker 1: Another example is like the Earth's axial tilt. You know,

1093
00:51:51,880 --> 00:51:54,959
Speaker 1: we have enough axial tilt to give us variation, which

1094
00:51:55,120 --> 00:51:59,080
Speaker 1: leads to beautiful falls in Virginia, I'm sure, But it's.

1095
00:51:58,960 --> 00:52:04,600
Speaker 3: Boring in California. Yes, And you don't get snow for Christmas,

1096
00:52:04,680 --> 00:52:06,680
Speaker 3: which makes it feel like not Christmas, which I know

1097
00:52:06,680 --> 00:52:08,400
Speaker 3: because I lived in California for a while.

1098
00:52:08,560 --> 00:52:10,560
Speaker 1: Hey, it snows in California and you can drive to

1099
00:52:10,560 --> 00:52:13,120
Speaker 1: the snow. It's optional. That's the best thing about the snow.

1100
00:52:13,280 --> 00:52:14,920
Speaker 1: You know, like stuck with it?

1101
00:52:15,920 --> 00:52:17,680
Speaker 3: All right, that's fair. I grew up in Ohio and

1102
00:52:17,719 --> 00:52:19,399
Speaker 3: I did feel stuck with it sometimes.

1103
00:52:19,120 --> 00:52:19,920
Speaker 2: Yeah, exactly.

1104
00:52:20,280 --> 00:52:22,720
Speaker 1: And if you didn't have any axial tilt, that wouldn't

1105
00:52:22,760 --> 00:52:26,279
Speaker 1: give you any seasonal variations. And there's some suggestion that

1106
00:52:26,400 --> 00:52:29,360
Speaker 1: like having some variation is good for creating diversity and

1107
00:52:29,400 --> 00:52:31,960
Speaker 1: competition and all this kind of stuff. And again, these

1108
00:52:32,040 --> 00:52:34,920
Speaker 1: arguments are not from evidence. There's no like experiments or

1109
00:52:34,920 --> 00:52:38,600
Speaker 1: calculations that say this tilt is perfect. It's really just

1110
00:52:38,680 --> 00:52:42,239
Speaker 1: like retrospective is saying we had it, this seems important

1111
00:52:42,280 --> 00:52:44,879
Speaker 1: and therefore it must have been crucial. But I don't

1112
00:52:44,880 --> 00:52:46,279
Speaker 1: think the argument really holds up.

1113
00:52:46,719 --> 00:52:48,560
Speaker 3: I mean, so many of these arguments seem to be

1114
00:52:48,640 --> 00:52:51,759
Speaker 3: things that like maybe turned the diversity nub up or

1115
00:52:51,840 --> 00:52:55,360
Speaker 3: down and maybe speed up or slow down the process.

1116
00:52:55,400 --> 00:52:58,400
Speaker 3: But human intelligence only popped up once. Yeah, and so

1117
00:52:58,480 --> 00:53:02,480
Speaker 3: I don't like, do you need seven million species before

1118
00:53:02,520 --> 00:53:05,759
Speaker 3: you get intelligence or like, I'm not entirely sure how

1119
00:53:05,800 --> 00:53:09,040
Speaker 3: this relates to intelligent life that you could communicate with.

1120
00:53:09,400 --> 00:53:11,200
Speaker 3: I think it just creates diversity, but maybe it just

1121
00:53:11,239 --> 00:53:15,759
Speaker 3: creates a lot more beetles wasps, which is awesome. I

1122
00:53:15,840 --> 00:53:18,120
Speaker 3: want to be in the world with the most beetles species.

1123
00:53:18,440 --> 00:53:20,520
Speaker 3: But I don't necessarily know that all of these things

1124
00:53:20,560 --> 00:53:23,000
Speaker 3: are necessary for creating intelligent life. I don't think we

1125
00:53:23,040 --> 00:53:25,799
Speaker 3: really understand why we ended up the way we are.

1126
00:53:26,160 --> 00:53:28,520
Speaker 1: So if we find an alien planet and is covered

1127
00:53:28,600 --> 00:53:31,160
Speaker 1: in wasps and beetles, we can drop you on that planet.

1128
00:53:31,560 --> 00:53:35,239
Speaker 3: Yes, if I can convince my kids.

1129
00:53:36,239 --> 00:53:39,160
Speaker 1: And you want credibility for your opinions about life in Virginia, huh,

1130
00:53:39,200 --> 00:53:41,000
Speaker 1: I think you just blew up your credibility there.

1131
00:53:41,800 --> 00:53:45,319
Speaker 3: Virginia's motto is Virginia is for lovers. And when we

1132
00:53:45,360 --> 00:53:48,040
Speaker 3: first moved here, we were amazed by how many different

1133
00:53:48,120 --> 00:53:49,960
Speaker 3: kinds of spiders there were. And I know I'm not

1134
00:53:50,000 --> 00:53:52,600
Speaker 3: selling Virginia very well, but we kept joking about getting

1135
00:53:52,600 --> 00:53:56,000
Speaker 3: shirts of Virginia is for spiders. But anyway, there's lots

1136
00:53:56,040 --> 00:53:57,560
Speaker 3: of cool diversity here is my point.

1137
00:53:58,640 --> 00:54:00,680
Speaker 1: Yeah, so you know in the and a lot of

1138
00:54:00,680 --> 00:54:03,959
Speaker 1: these arguments again are like, here's how life evolved on Earth.

1139
00:54:04,000 --> 00:54:07,160
Speaker 1: This seemed to be an important factor, but we don't know, right.

1140
00:54:07,239 --> 00:54:09,759
Speaker 1: The takeaway message here is that we just don't know.

1141
00:54:10,160 --> 00:54:13,960
Speaker 1: And by focusing on the particular outcome of life on Earth,

1142
00:54:14,239 --> 00:54:17,400
Speaker 1: it makes the argument pretty weak. And you could equivalently

1143
00:54:17,480 --> 00:54:20,640
Speaker 1: argue like, hey, what are the chances that Daniel is

1144
00:54:20,680 --> 00:54:22,400
Speaker 1: here and is on this podcast?

1145
00:54:22,960 --> 00:54:23,160
Speaker 2: You know?

1146
00:54:23,239 --> 00:54:25,800
Speaker 1: And you could even say, given that my parents existed

1147
00:54:25,880 --> 00:54:27,799
Speaker 1: and that they meet and all these things, what are

1148
00:54:27,800 --> 00:54:30,640
Speaker 1: the chances Well, of course the chances are tiny, right,

1149
00:54:30,760 --> 00:54:32,840
Speaker 1: But what are the chances of my parents have some

1150
00:54:33,120 --> 00:54:35,280
Speaker 1: kid that maybe then grows up to be a physicist

1151
00:54:35,320 --> 00:54:38,440
Speaker 1: and starts some kind of podcast like not that small?

1152
00:54:38,760 --> 00:54:41,640
Speaker 1: And that's really the question we're asking, right, is we

1153
00:54:41,800 --> 00:54:44,160
Speaker 1: know this is a huge variation of conditions out there

1154
00:54:44,160 --> 00:54:46,680
Speaker 1: in the universe, but what does that mean about how

1155
00:54:46,719 --> 00:54:49,960
Speaker 1: common life is? If we only ask where are there

1156
00:54:50,040 --> 00:54:52,720
Speaker 1: humans that look like us? Then of course the answer

1157
00:54:52,760 --> 00:54:53,640
Speaker 1: is going to be nowhere.

1158
00:54:53,800 --> 00:54:54,960
Speaker 2: Or almost nowhere.

1159
00:54:55,360 --> 00:54:57,080
Speaker 1: But that's not the question we want to answer, right,

1160
00:54:57,120 --> 00:54:58,879
Speaker 1: We just want to know if there's anybody else out

1161
00:54:58,920 --> 00:54:59,920
Speaker 1: there thinking about.

1162
00:54:59,680 --> 00:55:03,000
Speaker 3: The uni right, and if they care how we smell.

1163
00:55:04,920 --> 00:55:08,040
Speaker 1: Exactly, and if they like nice weather or not, you know,

1164
00:55:08,560 --> 00:55:10,360
Speaker 1: and what they mean by nice weather anyway.

1165
00:55:10,920 --> 00:55:13,160
Speaker 2: That's right. But fortunately we are going to learn.

1166
00:55:13,080 --> 00:55:15,680
Speaker 1: A lot about this in the coming years. It's fairly

1167
00:55:15,760 --> 00:55:18,680
Speaker 1: recently that we've even seen planets around other stars. That

1168
00:55:18,719 --> 00:55:21,879
Speaker 1: whole science is now like only twenty five years old,

1169
00:55:22,120 --> 00:55:23,520
Speaker 1: and it's growing exponentially.

1170
00:55:23,760 --> 00:55:23,920
Speaker 2: You know.

1171
00:55:23,960 --> 00:55:27,279
Speaker 1: The number of planets that humans knew about went from

1172
00:55:27,320 --> 00:55:32,000
Speaker 1: like six for like thousands of years to like seven, eight, nine,

1173
00:55:32,040 --> 00:55:34,919
Speaker 1: and then back to eight, and now it's exploding. Now

1174
00:55:34,920 --> 00:55:38,560
Speaker 1: we're like we've seen five thousand planets around other stars.

1175
00:55:38,600 --> 00:55:41,640
Speaker 2: It's an incredible time to be a human.

1176
00:55:41,680 --> 00:55:44,680
Speaker 1: It's like pre this moment and post this moment, and

1177
00:55:44,760 --> 00:55:47,520
Speaker 1: it really turns the page scientifically in terms of our

1178
00:55:47,600 --> 00:55:50,880
Speaker 1: knowledge of the universe. But we're still in that like

1179
00:55:50,960 --> 00:55:55,160
Speaker 1: exponential growth. We're building all sorts of crazy new space telescopes,

1180
00:55:55,200 --> 00:55:58,440
Speaker 1: Like there's the haveb X telescope, which is designed exactly

1181
00:55:58,640 --> 00:56:01,200
Speaker 1: just to do this. It's to float in space and

1182
00:56:01,280 --> 00:56:04,879
Speaker 1: look at other stars, and it's got this amazing sunshade

1183
00:56:04,880 --> 00:56:06,880
Speaker 1: that's going to block out the light from the stars

1184
00:56:06,880 --> 00:56:09,120
Speaker 1: so we can just see the planet. It's going to

1185
00:56:09,160 --> 00:56:12,480
Speaker 1: be incredible to discover planets. So we're gonna look back

1186
00:56:12,520 --> 00:56:15,000
Speaker 1: at the time when we only saw five thousand planets

1187
00:56:15,000 --> 00:56:17,800
Speaker 1: as like the early days of this kind of science,

1188
00:56:17,880 --> 00:56:19,640
Speaker 1: And in ten years we're going to know so much

1189
00:56:19,680 --> 00:56:21,640
Speaker 1: more about the kind of planets that are out there.

1190
00:56:22,000 --> 00:56:24,279
Speaker 1: We're going to be measuring what's in the atmosphere of

1191
00:56:24,320 --> 00:56:27,640
Speaker 1: those planets. We might detect oxygen, we might see biosignatures,

1192
00:56:27,800 --> 00:56:31,000
Speaker 1: we could see techno signatures. So it's an exciting moment

1193
00:56:31,040 --> 00:56:33,720
Speaker 1: because we don't know the answers to these crucial questions,

1194
00:56:33,800 --> 00:56:35,719
Speaker 1: but we might be about to find.

1195
00:56:35,480 --> 00:56:39,480
Speaker 3: Out, I hope. So I can imagine HabEx giving us

1196
00:56:39,520 --> 00:56:42,440
Speaker 3: a lot of data to tinker with Drake's equation. I'm

1197
00:56:42,480 --> 00:56:45,240
Speaker 3: already super excited, but I will be really super duper

1198
00:56:45,320 --> 00:56:48,800
Speaker 3: excited when we find a second example of any life,

1199
00:56:48,840 --> 00:56:52,480
Speaker 3: intelligent or not, somewhere else. I feel like that will

1200
00:56:52,480 --> 00:56:54,520
Speaker 3: give us a lot of information that we really need

1201
00:56:54,560 --> 00:56:56,800
Speaker 3: to try to nail this stuff down absolutely.

1202
00:56:56,880 --> 00:56:59,400
Speaker 1: Even just two examples, you get to draw second marble

1203
00:56:59,400 --> 00:57:02,160
Speaker 1: from the huge bag. If it's also an orange marble,

1204
00:57:02,200 --> 00:57:04,760
Speaker 1: you're like, wow, Okay, maybe they really are just orange marbles,

1205
00:57:04,760 --> 00:57:07,720
Speaker 1: but it's something weird and crazy, which is my personal preference.

1206
00:57:08,080 --> 00:57:09,839
Speaker 1: And then we're going to learn so much about life

1207
00:57:09,840 --> 00:57:12,359
Speaker 1: in the universe. And the frustrating thing to me and

1208
00:57:12,440 --> 00:57:14,239
Speaker 1: the exciting thing is that the answers.

1209
00:57:13,920 --> 00:57:15,960
Speaker 2: Are out there. There's either life.

1210
00:57:15,680 --> 00:57:19,880
Speaker 1: Out there right now sliming around and enjoying its various weather,

1211
00:57:20,040 --> 00:57:22,720
Speaker 1: or there's not. You know, the facts are out there.

1212
00:57:22,760 --> 00:57:24,680
Speaker 1: We just need to like gather them. We just need

1213
00:57:24,680 --> 00:57:26,360
Speaker 1: to like scoop up the information. We need to be

1214
00:57:26,400 --> 00:57:29,960
Speaker 1: smart enough and devote enough energy and frankly money to

1215
00:57:30,240 --> 00:57:33,320
Speaker 1: just like purchasing this information from the universe.

1216
00:57:33,680 --> 00:57:33,919
Speaker 2: Yep.

1217
00:57:34,040 --> 00:57:36,440
Speaker 3: My bet is that the alien life is hiking in

1218
00:57:36,480 --> 00:57:39,600
Speaker 3: the equivalent of Shannandoah National Park because there's nowhere more

1219
00:57:39,640 --> 00:57:42,240
Speaker 3: beautiful on this planet. But I guess we're just going

1220
00:57:42,320 --> 00:57:43,439
Speaker 3: to have to wait and see.

1221
00:57:43,720 --> 00:57:45,840
Speaker 1: Yeah, well, I guess we'll find out. Is the universe

1222
00:57:45,840 --> 00:57:47,919
Speaker 1: for lovers or is the universe for spiders?

1223
00:57:48,520 --> 00:57:48,920
Speaker 4: Oh?

1224
00:57:48,960 --> 00:57:52,480
Speaker 3: I hope it's for lovers. I really hope there's a

1225
00:57:52,520 --> 00:57:54,840
Speaker 3: whole book about turns out life somewhere else as spiders

1226
00:57:54,840 --> 00:57:56,440
Speaker 3: and how we interact with them, But I can't remember

1227
00:57:56,440 --> 00:57:58,360
Speaker 3: the name of it now. Matt Inman, though, was the

1228
00:57:58,360 --> 00:57:59,600
Speaker 3: one who suggested that I read it.

1229
00:58:00,200 --> 00:58:02,800
Speaker 1: There's a great science fiction novel by Adrian Tchaikowsky called

1230
00:58:02,880 --> 00:58:06,200
Speaker 1: Children of Time where spiders become intelligent and.

1231
00:58:06,160 --> 00:58:07,160
Speaker 2: It's really fascinating.

1232
00:58:07,600 --> 00:58:07,880
Speaker 3: That's it.

1233
00:58:08,520 --> 00:58:12,680
Speaker 1: Thanks, it's a great book, totally recommended. Well, anyway, thanks

1234
00:58:12,720 --> 00:58:15,040
Speaker 1: everyone for joining us on this tour of one of

1235
00:58:15,080 --> 00:58:19,360
Speaker 1: the most important, most ancient, and least answered questions in

1236
00:58:19,400 --> 00:58:22,560
Speaker 1: all of science, whether we are alone in the universe,

1237
00:58:22,600 --> 00:58:24,360
Speaker 1: what we can know, what we do know, and what

1238
00:58:24,400 --> 00:58:26,120
Speaker 1: we might know soon in the future.

1239
00:58:26,360 --> 00:58:27,960
Speaker 3: I thought it was going to be as California or

1240
00:58:28,040 --> 00:58:30,640
Speaker 3: Virginia better, but no, probably you're right, that's probably a bigger.

1241
00:58:30,440 --> 00:58:33,520
Speaker 1: Question, and that's a question we actually already know the

1242
00:58:33,520 --> 00:58:36,760
Speaker 1: answer to. All right, bye, everyone, have a great time,

1243
00:58:37,040 --> 00:58:37,760
Speaker 1: even those of you.

1244
00:58:37,760 --> 00:58:38,800
Speaker 2: Who live in Virginia.

1245
00:58:38,840 --> 00:58:50,120
Speaker 3: Thanks everyone. Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio.

1246
00:58:50,320 --> 00:58:52,840
Speaker 3: We would love to hear from you, We really would.

1247
00:58:53,000 --> 00:58:55,760
Speaker 1: We want to know what questions you have about this

1248
00:58:55,960 --> 00:58:57,640
Speaker 1: Extraordinary Universe.

1249
00:58:57,720 --> 00:59:00,720
Speaker 3: We want to know your thoughts on recent shows, suggestions

1250
00:59:00,720 --> 00:59:03,720
Speaker 3: for future shows. If you contact us, we will get

1251
00:59:03,760 --> 00:59:04,160
Speaker 3: back to you.

1252
00:59:04,400 --> 00:59:07,880
Speaker 2: We really mean it. We answer every message. Email us

1253
00:59:07,920 --> 00:59:11,120
Speaker 2: at Questions at Danielankelly.

1254
00:59:10,200 --> 00:59:12,280
Speaker 3: Dot org, or you can find us on social media.

1255
00:59:12,360 --> 00:59:16,160
Speaker 3: We have accounts on x, Instagram, Blue Sky and on

1256
00:59:16,240 --> 00:59:18,200
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1257
00:59:18,640 --> 00:59:20,160
Speaker 3: and K Universe.

1258
00:59:20,280 --> 00:59:21,800
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