This is the Drake Equation, first presented in 1960, by Dr. Frank Drake, an astronomer
at the National Radio Astronomy Observatory in Green Bank, West Virginia, wherein N equals
the number of civilizations in the Milky Way Galaxy whose electromagnetic emissions are
R equals the rate of formation of stars suitable for the development of intelligent life.
f-p equals the fraction of those stars with planetary systems.
n-e equals the number of planets per solar system with an environment suitable for life.
f-l equals the fraction of suitable planets on which life actually appears.
f-i equals the fraction of life bearing planets on which intelligent life emerges.
f-c equals the fraction of civilizations that develop a technology that releases detectable
signs of their existence into space.
L equals the length of time such civilizations release detectable signals into space.
Got all that?
Since 1961, scientists have used the Drake Equation to stimulate thinking about finding
life elsewhere in the universe.
In the words of one of our greatest cosmological minds:
Are we alone?
How common is this thing called life?
This thing called intelligence.
Where did we come from?
What are the possible fates of intelligent beings?
Need we necessarily destroy ourselves?
Might there be a, a, a, a bright and very long future for the human species.
We tend to have such a narrow view of our place in space and in time and the, uh, the
prospect of, of making contact with extraterrestrial intelligence works to deprovincialize our
And I think for that reason, the search itself, even without a success, has a great merit,
I thought I'd share just a couple of things from my space flight experience that might
apply to this.
I was blessed to live and work in space for 104 days.
Had the opportunity to look out the window and see earth in this just overwhelmingly
It certainly is a life changing experience.
And I get asked a lot did I, did I see aliens while I was in space?
It's kinda like the bathroom question, and you're going to get that and you know, did
you see aliens?
And I can say, not that I know of,.
But I'm interested in our panel session tonight because I'd like to think, you know, as earthlings,
what do we have to look forward to out in this universe when we consider life and other
places, and does it always have to be life that's with respect to, to us, to what we
consider to be a life and intelligence?
So I'm looking forward to introducing our panelists and getting into this, Our first
participant is the director of the Carl Sagan Institute and a professor in astronomy at
Her research focuses, focuses on modeling new worlds and how to spot signs of life.
Please welcome Lisa Kaltenegger.
Also joining us is director of astrobiology at Columbia University and a Global Science
Coordinator for the Earth-Life Science Institute's Origins Network at the Tokyo Institute for
Please welcome them here at Caleb Scharf.
Also with us tonight is a Distinguished Scholar at the Library of Congress and a Director
of the AI, Mind and Society (AIMS) Group at the University of Connecticut, a philosopher
and cognitive scientist.
Please welcome Susan Schneider.
And our final participant tonight researches the origin of life and how to discover it
on other worlds.
She is an Assistant Professor in the School of Earth and space exploration at Arizona
Please welcome Sara Walker.
So before we can talk about finding alien life, we need to start with a clear operating
definition of what life is.
How do we actually define what life is? we'll just go right down the line here.
So I think I'm going to start out, but being a little bit cheeky because I'm an astronomer
so I don't have to give you the real definition of what life is and most of my biology colleagues
actually tell me I'll know it when I see it.
So good luck with that because the other stars are very far away, but we are working on it.
So to me, what's really important is there's something that I can spot in the air of another
planet, the atmosphere.
Like we have oxygen in our own planet for example.
Is there something that I can spot that life does that modifies a planet its environment
enough so I can actually pick that up by looking at that planet with my big telescope, and
so that definition encompasses a huge amount of life, all the life that changes to signature
gases in the air of another world, and Carl Sagan looked at our world and what he saw
was the combination of oxygen with reducing gas like methane and that's a tell-tale sign
for a nice warm world like ours.
That life's happening right there.
And so that's what I use, but if anybody comes up with a better definition of other gases
I can look for, I'd be more than happy to pass this along.
We’re already on to gases.
And that was the first answer.
Yeah, so I need to, defining life is one of those questions, I think as scientists, we
all know that you'll get 100 different answers or you'll get a kind of blank stare.
I'm going to be a little cheeky as well, and perhaps a little contrarian and say that you're,
in some ways I think it may be the wrong question right now and there are a few reasons for
Part of the reason is quite simple and it's just that it's clear that what we consider
to be life is actually a confluence of multiple phenomena in different ratios depending on
what you're talking about.
That makes it extremely complicated a question, but I'll say two other things I think make
it a difficult question right now, and the first is that when we think about life, we
think about life here in this room, in this audience, on uh, on the bottom of your shoe,
whatever that has evolved after 4 billion years.
It's the product of 4 billion years of evolution and that may be different than whatever happened
4 billion years ago.
It may be very different to what was the first thing or first system that we might associate
Then the other point I want to bring up is I think we can't quite answer that question
yet because we don't know, and I think maybe some of the other panel members may have some
insight to this, whether you can build life out of other stuff, so whether life can be
a substrate, independent, or more universal than we think about, not necessarily building
out of silicon or anything like that, but building life in software.
If you could do that, it would suggest that life is something that can happen when you
have components that can build enough complexity for it to, for it to sort of emerge.
So that's my contrarian answer that we can't quite answer that question of defining life
So that's really nice.
I'm a philosopher, so definitions are always a train wreck.
And the worry here is that if you define life in terms of life as we know it on earth, all
cases of life that we know are related.
So we've got one instance that we know about and so if we make a definition based on that
instance and we go look for life somewhere else, it may be that we failed to detect life
because we've narrowed our definition so much that we are just the tip of the iceberg.
There are all sorts of intriguing cases of life.
So I agree with both of you, you know, to not use a very constrained definition.
NASA's Astrobiology Institute has an intriguing definition which I sometimes refer to, which
is a self sustaining chemical system capable of Darwinian evolution.
I like that.
But then I kinda think again as a philosopher, wait a second, what if AI is self-sustaining
and has all sorts of intriguing properties, but the instance that we have is created by
intelligent design, that is we're the designers.
We make the AI systems, and it doesn't evolve in a Darwinian fashion.
So I'm still not 100 percent behind the NASA definition either.
I can agree with that.
I'm also not behind the NASA definition.
So I think one of the problems that we often encounter is assuming that life is a chemical
phenomenon, and I think there's a confusion between the scale at which life emerges, which
is probably chemical, and the definition of life, which is likely not related to chemistry
necessarily and could apply to AI.
So I liked that Lisa brought up the, the.
I know it when I see it.
You hear this so much in the astrobiology community and I always make this joke about
Like if, if I know it, when I see it, I feel very alive and so you guys are observing me
I guess I'm alive because you know it and when you see it, but like if nobody is observing
me, am I still alive?
So that doesn't seem like a very good objective criteria for science.
So I think one of the problems that we face as astrobiologists is that our definitions
are really premature because we don't actually have a theory for life.
Um, and so what I mean by that is I, the way I think about living systems is really trying
to understand what is life at a fundamental level.
And a lot of our descriptions are kind of at this very high level where we're talking
about life being reproducing or about compartmentalization or metabolism or chemical self-sustaining
And those are probably attributes of life but not really the core property of life.
The property that would be universal in the sense that Caleb was talking about.
And if we think about what life is doing that's very unique, in my mind it's information processing
And that we don't really see any other kind of systems that use information in the way
that biology does and I think AI is an excellent example of that.
DNA in your cells and how that information gets read out and actually controls the function
of yourselves is another example.
And to that point, if we start thinking about these sort of more abstract ways of thinking
about life in terms of information and the way information interacts with the physical
world as being a way of quantifying life, suddenly life is not this black or white.
Yes, this is alive.
No, this is not alive, but we could actually derive measurable criteria for life and that
there's actually a spectrum of living things.
And so AI might fall in that spectrum.
Chemical Systems might fall in that spectrum, but so might cities and multicellular organisms,
or unicellular organisms.
And so I think one of the challenges for astrobiologists moving forward is really to challenge ourselves
to think outside the box about what life is and what the underlying laws might be of life,
and whether there are principles that are really universal.
Well, I liked the way...
I think one of the things that I completely agree, and this is where you get that full
scientific insight that we just like talk and discuss and it's fun and then we trying
to come up with something, is the search that we have going now on the thousands of other
worlds that we've found and detected does need some kind of definitions that we figured
out what we can spot or what we could look for.
However, what we do is we keep our eyes open for weird stuff.
Weird stuff that we can’t explain geologically, right, and then we'll take that and say, look,
because we have this one case earth and earth is amazing and has a wide range of life when
we look at it, however, it could be completely different somewhere else, but we'll only get
that when we look somewhere else, as we are now doing, and we're trying to also recreate
life in the lab.
That's what a lot of our biologists colleagues are trying to to work out now.
And if that would work out then we could change the chemical mix.
But right now it's basically a two pronged approach, I would say, looking out and trying
to figure out what we can find and what makes no sense.
What's usually the fun in science, the eureka moment was like, oh my God, this is nothing
I would have ever expected.
That's what we really like in a way.
We don't know what to do after.
But that's where it becomes fun.
And the other thing is like people trying to do this theoretically and trying to do
it practically in the lab from the most basic chemical compounds.
And I think it's really, really cool to be alive right now because we're 2000 years,
a little bit more, people were asking whether we're alone in the universe and we're so close
to figuring it out.
I suspect we would be asking it for 20,000, 30,000, 50,000 years.
And that's what's so cool about it.
I think that's a really nice lead in to part two, which is finding life.
Since 1992, more than 3,500 exoplanets had been found orbiting stars other than our sun.
And 60 percent of these are rocky planets, not unlike ours.
So Lisa, let's start with you and the opening film.
We heard from Carl Sagan himself about the value of searching for life out there in the
As Director of the Sagan Institute.
Can you tell us how that search is going?
I mean, there's a lot of things going on.
So I think, one of the most fascinating things for me, so as you were saying, about 25 years
ago, this whole thing is like are there other planets out there, are there worlds, required
a bottle of wine and a lot of different opinions.
Right now we found nearly 4,000 worlds orbiting other stars, alien suns.
So when you look up in the sky, doesn't work in Manhattan, but works once you are outside.
I tried yesterday, I could find two stars.
When you're out and you actually.
Well, one thing that works in Manhattan, if you're out and you look the sky and you count
one, two, one out of two stars or one out of two suns that you see in the night sky
has a planet, and one out of five has a planet that could be like ours.
And what that means is that it's small enough to be a rock and at the right distance from
this hot star, where it's not too hot and not too cold so you can have liquid water,
one out of five and we have 200 billion stars in our Milky Way, our galaxy alone.
So if you do the math, we've 40 billion interesting places to look and we have no idea whether
there is life out there because we don't have the telescopes yet that are big enough to
actually catch the light from these planets to check.
However we're building those and the first one is going to launch in two years.
It's the James Webb Space Telescope.
And that one at the edge of the technical possibility will have the capability to spot
these gases that life produces in the air of other worlds that could be like ours.
So the search is going well so far.
I like our odds.
I have no answer and a good answer actually if anybody ever asks you, when you come out
of this panel, for example, what the chances are that there's life out there in the universe.
A good friend of mine, one of the discoverers of the first exoplanets, Michel Mayor always
says 50 percent plus minus 50.
I think it's a good way to put it.
And we know there are a lot of other missions that are happening as well and I hope we'll
get a chance to discuss some of them too.
Caleb, When, when you think about this, what are the parameters for looking for life on
If you could look for what you want.
What would you be looking for?
So one of the things I'm very interested in with my colleagues is understanding even something
as fundamental as the nature of climate.
You mentioned the idea of the planet needing to be just at the right distance from its
parent star where it's not too hot, not too cold.
Goldilocks zone or whatever you want to call it, but that itself is actually a very complex
problem as, as you well know.
Uh, so for example, uh, we're trying to take super computer simulations of planetary climate
and model alien worlds and find out what happens when you change the day length of a planet.
What happens when you change the tilt of the planet, what happens when you change the shape
of the orbit, what happens when you change the gravity of a planet?
And so on.
And it turns out to be a difficult problem
Yeah no kidding
Just to answer whether or not the surface environment of a planet, maybe temperate,
which is kind of one of our methods of selecting out candidate planets for then trying to probe
deeper with these, these great new telescopes looking for chemical signatures and so on.
You kind of need to know the, the thermal environment, the climate environment.
Um, so I can give you an example of what happens when you slow a planet like the earth down.
You might think.
Well, what, how that change climate will actually completely alters the circulation patterns
of the atmosphere on a planet.
And our models contain oceans and atmospheres and chemistry and salt, and we're finding
that you change the rotation rate of a planet, you actually warm up the poles and you cool
down the equator, but you also do other things.
If the planet has water, it begins to build certain patterns of cloud that play a role
in reflecting stellar radiation, for reflecting sunlight back out into space.
And that also plays a role in setting the climate state.
So the bottom line is we're trying to come at this problem from many different directions
and it's all complicated.
Uh, which is good in the sense because we have jobs to do.
If it was easy, we wouldn't be doing it.
Um, so some, some of the parameters are the raw sort of biochemical signatures, but other
parameters have to do with just understanding that the environment, the climate state of
And that's a challenge.
Sorry, go ahead.
So what was, what Caleb was saying.
And that's absolutely true.
So we have a different approach to this, right?
So that we have many, many groups who have this climate model that was done for the earth.
so we have one at the Carl Sagan Institute, you've one with several where we basically
making a huge data cube, if you want, where we're actually making our models do things
for a longer day lengths, for bigger gravity.
But the problem that we're encountering of course is that we have no data sample that
you can compare that to because we don't have an earth that happens to be heavier, right?
We have some information about an earth that's younger and we have this amazing artists'
impression that you see behind us of what these planets that we've discovered or that
astronomers have discovered, could be like.
Some have one sun, some have two suns, the suns up there.
And man, try to model the climate of the earth and put a second sun in.
This model was never designed to have two suns because earth was never designed to two
suns in a way, so we're getting a lot of insights and the question really is also if the climate,
when could we find the signs of life even if they exist, some climate conditions will
actually make it impossible for us to spot them, and some climate conditions will make
it easier for us to spot them.
And with thousands of planets out there, what we're trying to do is pick the easiest ones
to tease this out, and one last point is that when Caleb and I were talking about the habitable
zone, there's no way to say that outside of the zone, there couldn't be life.
There could be life on icy moons, for example, like Europa on Solidus, but it would be hidden
from our view because this ice layer would basically keep all the gases, the only thing
that we can really see from far, far away hidden from our telescopes.
We'd have to go there, drill a hole and check if there are fish or anything else, but so
this is why this definition of the habitable zone, just to make sure, it's not where there
can be life, it's where we without going there can pick it up if it exists.
Just to add one tiny little interesting piece too that.
You mentioned the icy moons, and that's absolutely an essential thing to remember because if
you look at our solar system, we have this picture of this little oasis world.
I think one of those posters talks about the oasis earth sitting closer to the sun, but
if, for example, having liquid water oceans defines an oasis, then actually the majority
liquid water oceans in our solar system are in the outer solar system.
If you add up all the potential liquid water inside Europa, inside Enceladus, inside even
Titan, and possibly even Pluto, it's about 13 times the total volume of liquid water
Except it's in these dark oceans, these ocean sea, all the way by icy crusts.
So for all we know our solar system is teeming with more life, but it's locked away in these
so Sara we have the potential with places like Mars where we might actually be able
to get there someday.
But I guess I'd like to ask you, you know, you got the Mars 2020 and the Exo Mars 2020
rovers that are going to get a much closer look at the surface of Mars than we've ever
So what should they be looking for?
Um, and what do you expect they'll find?
I'm not convinced there's life on Mars actually.
Well, that's what I think that's an okay answer actually.
So I think Mars is fascinating.
But, um, but I've been really intrigued with this idea that life um really needs to take
over an entire planet.
And so if you look at life on earth, everything about the earth's system is defined by the
presence of life in some sense, even like the biogeochemical cycles.
So the cycling of elements is controlled by life.
And that's something really fascinating about what humans are doing now as we're starting
to control those, those biogeochemical cycles.
Um, so if you, if you look at something like the models that we think Caleb, we're talking
about, one of the things I felt really intriguing hearing about those is we don't even know
how to model earth without life, right?
Um, and so I think this idea that, that, that life really becomes embedded in a planet is
Um, and I guess this idea about, um, back to like thinking about definitions of life
and what we're actually looking for.
We think of life as this, this chemical phenomena and a cell as the fundamental unit for life
and so we should be looking for cells on Mars, but that may be too narrow a view, and if
you do have this kind of expanded view and are really looking for more fundamental basic
processes of life, it really opens your horizons for things that you might look for.
And so when I think about looking for life, I'm not really thinking about looking for
cells on a planet or molecules in an atmosphere.
I think about looking for an entirely new sector of physics and that seems like kind
of an unusual way of thinking about it.
But we have some really amazing mathematical theories of the world.
We have quantum mechanics and general activity and these amazing revolutions and our understanding
of the natural world.
And we don't have any theories that explain the existence of life or the properties of
And so I really think it's, it's a new frontier for us in astrobiology to really understand
as combining observations and experiments that we're doing here on earth and really
think differently about what kind of things we're looking for.
And so when I think about looking for life, I think about what are the mathematical structures
that we use to describe life on earth that we should be thinking about, how to look for
those on other planets.
Um, and one of the ways that that has been really incredibly successful in studying life
across all scales for life on earth is this idea of using networks.
Um, and so, um, so probably everybody in here is part of a social network, right?
Is anybody here a part of a social network?
Raise your hand.
At least one, you're in a room with people.
So you're in a social network, but you're probably also in a social network online.
And you can actually represent networks mathematically and, and they're, they're quite simple mathematical
Um, everybody in this room would be representatives of a circle and if you're friends with each
other, you'd have a line between you and you can actually study the statistics of those
kinds of systems.
Um, and this is really interesting because if you look at systems like the chemistry
happening in yourselves or the structure of the internet or the structure of Facebook,
there's a lot of regularities in the, in the way those networks are structured and a lot
of that has to do with the way information is structuring those systems.
So, so if you think about a social network, really, you're not interacting with those
people physically, you're interacting with them through, through information technology
or some kind of information exchange.
And so what I find intriguing is trying to actually think about how we can use insights
from complex systems to look for life on earth in particular, um, maybe, um, you know, Mars
atmosphere or atmospheres of other planets might have some signatures in the actual system
level organization of the planet.
Um, and what I mean by that is you could actually just like, we can represent chemistry.
Um, so, so the way we represent chemistry and yourselves as a network, as we say, the
molecules interact, so they would be the nodes in the network and if they participate in
a reaction together, then they have a line between them.
Um, and so you can represent an atmosphere that way too.
It's just chemistry.
It has the same kind of mathematical representation.
And so some people have done some preliminary studies where they show Earth's atmosphere.
It looks more like the chemistry inside your cells than it does like Mars or Venus's atmosphere
from this network perspective.
Now that has a lot of work to be done to confirm that this is really like a system level property
of atmospheres of inhabited planets.
But if it is, it gives us a better window into thinking about what our biological systems
at a planetary scale, how do they shape planetary scale structure of the chemistry, and how
can we actually use that as a bio signature that's not just dependent on the particular
molecules participating in those networks, but actually the system level organization.
And so one of the ways that I tend to think about that, why looking at individual molecules
is bad, but maybe looking at system level properties is good for detecting life is you're
all made of atoms in this room, right?
But you wouldn't think of any individual atom in your body is alive, but you as a whole
system level entity are alive.
So it ought, it clearly has to be an emergent property of many interacting molecules.
Um, and so I think one of the things that we need to start doing is actually start using
those kinds of tools for thinking about our search for life.
It gets hard with exoplanets because you get so little data.
Drives me nuts how little data-
So, so one of the things I find challenging for the future, so think like how do we actually
extract these kind of properties from that data?
Um, but I think that there are new horizons for thinking about how we search for life
that aren't just the way that we've been thinking about it in the past.
Um, and it really comes from trying to think more quantifiably about the search.
I think that actually leads Caleb into, you know, this consideration for the Fermi paradox
and which can be, you know, really with the question of where is everybody, you know,
where, I mean, where is everybody and who, who should we be looking at, you know, and
um, you know, this, this idea is the answer to the Drake question zero.
so maybe I'll just state what the Fermi paradox is.
And then then we have a little, uh, I think we have a little movie to show.
So the Fermi paradox is this idea that if there is life out there, if life happens reasonably
often in our galaxy, for example, then our galaxy is pretty old, it's at least 10 billion
And so following our own trajectory, there's been plenty of time for some species out there
to have come into existence, if it's being lucky or unlucky, depending on your perspective,
it became intelligent and technological and decided to try to go between the stars.
And the interesting thing about that is it turns out that once you start doing that,
you occupy the galaxy pretty quickly.
And so this raises the question, if life is not incredibly rare or if there isn't something
that prevents it from doing this, and where is everybody?
Why hasn't it shown up?
Of course some people feel it has shown up, but we won't go there.
That's a different question.
Um, so to give us, to illustrate this, I don't know if we have the little Fermi video ready.
So let me explain what this is.
This is actually the work of Jonathan Carol Neylanbach and Adam Frank, who I've been working
with, and this is a picture of our galaxy, but it's a highly idealized model of our galaxy.
What you're looking at, each little point of light, each little sphere represents about
two and a half million stars and the colors correspond to interstellar species relocating
themselves, expanding, I, I would say colonizing, but that word have such negative connotation
Uh, they're, they're, they're expanding out.
Each color corresponds to particular technological species.
Now, what you're seeing in this representation is a pretty active galaxy.
In the middle, things come and go because there are things like supernova that go off
and essentially sterilize big pieces of our galaxy.
So civilizations in the middle of our galaxy kind of like building a house in Hawaii.
It's like, yeah, this looks good.
I know there's a volcano, but you know, and that maybe something that happens in the center
of our galaxy where there're many more stars, many more supernova and other violent events
that might actually sterilize pieces of the galaxy.
Now this is an exaggerated model.
The part of the reason for looking at this question this way is that things move around
in our galaxy and stars have motion and that actually encourages the spread of an interstellar
species because you may not have to have such wonderful rocket ships to go between stars
if the stars themselves every so often come closer to each other.
So that's part of what we were trying to model.
It's a very exaggerated model because in that 40 million years that you just saw passing,
we assume that species can travel about half the speed of light when they decide to, but
even if you tune it down, and you make it much more difficult to travel between the
stars, and you make the occurrence of star-faring species much less frequent, you still discover
that it still is pretty easy to fill the galaxy with life.
So the bottom line is it reinforces this big open question of where is everybody?
So that's essentially the Fermi paradox brought up to date.
I'll be contrarians.
So the point is that I teach astronomy 101, so I have like undergrad students with no
Uh, one of the questions that I asked, we asked them when we get to the Fermi paradox,
so Fermi basically decided that his answer was that the speed of light is our limit and
so you'd have to be incredibly motivated, or have a really good reason why you'd want
to spend so much of your time.
Like our closest star after the sun is four light years away.
So if you could go with 10 percent the speed of light, it's still a 40 year travel that
you have to survive.
You have to have energy and food for and you have to have a very good reason to go, right?
But what I do in my class, when we get to the Fermi paradox and to the Drake equation
and saying, look, I have this amount of money and we can go to one planet.
Let's assume the whole galaxy's teaming with them.
I have one planet that is 5000 years older than us and one planet that's 5000 years younger.
And then I poll my class and say which one should I spend my money on to go and visit?
And most of the time to always, except for one person who always wants to go back in
time because they're scared about something new, everyone wants to go to the further developed
one because they want to know what's going on.
And then if you take that, I love our planet, I love our species, I think the astronauts
are amazing, you know, let me say that.
But we only made it to the moon with people, right?
We made it with a rover to Mars.
It was great.
And to Titan with a satellite that we land in and so on, but we are really not that interesting
assuming there's lots of places you could choose from.
So I think we're just incredibly boring.
I love our planet.
I said that before.
I want to be nowhere else.
I think Susan is going to have something to say about this.
But just before that, just to say, one issue is you're introducing the factor of agency.
We try to avoid that in our modeling because we have no idea what agency is going to be
for other organisms or for other species.
Oh, just a quick comment.
So we are boring probably.
We're a relatively young planet and you know, if there are truly are alien technological
civilizations, they could be, you know, 50 million years older than us, so we may not
know what to look for.
But I do think it's interesting though that, you know, we do tend to think of this issue
in terms of this model of galactic expansion.
It's called the coral model, right?
Where we start in one spot and then we send out maybe Von Neumann probes which are AIs
or spaceships in the old fashioned way, and then they send out their ships and we expand,
but that's highly anthropomorphic.
But intriguingly we have already started interstellar missions.
We have Project Breakthrough Starshot, which in I believe 20 years is aiming to go to the
Alpha Centauri region and I think the speed that they're anticipating, if things work
I mean there's issues like space dust when you're.
I think the way they do it is that they're incredibly small, they're so light that they
can go very, very fast.
These little light sail ships.
But the point here is if you do want to expand in this way, even we have the resources to
begin to at least examine these other regions fairly cheaply.
I mean, each ship is fairly inexpensive.
Of course it takes a lot of energy to send the ships out.
But I think the question here is, will, are we being too anthropomorphic when we think
of the Fermi paradox, I mean, we're thinking of galactic expansion, but these civilizations
that are perhaps 50 million years older than us are thinking entirely differently than
So who knows, maybe they have already visited and we just don't know.
I hope one porter's call.
Don't take that wrong, okay?
I mean by our meek intellectual resources, there are dozens of intriguing responses to
the Fermi paradox, but there's been nothing that convinced me, uh, you know, either way.
I am actually, well, interested in asking Sara a question about the sort of information
approach to life, networks, and so on.
We automatically kind of think of it as, oh, life, will it's stuff here.
But could it be applied on a much grander scale to understand something like the Fermi
I hope so.
So I was first going to disagree with all of you because they don't think we're boring.
I think we are fascinating, just so you know, there's one person on the panel that doesn't
think we're boring.
I think we are the most fascinating thing in the universe.
It's really crazy that, that we're here having this conversation right now.
Um, but from the perspective of the Fermi Paradox, I mean, my resolution is, is very
similar to Susan's.
I just, I think we don't know what we're looking for and if we, if we understand life on earth
better, um, and we do, we develop these kind of quantifiable criteria to answer your question,
then we should be able to identify it.
And it might be that we identify in completely different ways than we had anticipated previously.
Um, and so one of the things that, oh, I made this argument before, that, that life isn't
a chemical phenomena.
Um, and I, I really do think it's not.
So when I say that, like cities are alive, I really think cities are alive and I think
computers are alive and I think AI is his life.
And so these are all examples of the same kind of information mattering to the world
and reemerging at different scales, and we don't really know how high up in a hierarchy
We know that that chemistry organized into unicellular organisms, and that those organized
into multicellular organisms.
And then we had social systems, and then we had cities, and we have technological civilization
that's now globally integrated, and now we're inventing artificial intelligence.
And so hi, how, how many scales are there to that kind of of living process and hierarchy?
And some very advanced life could look entirely different than anything that we could anticipate
right now or life in different media could look entirely different.
It doesn't need to be the kind of chemistry that we have on earth today.
So I think what we really need to understand is what is, what life is and what it's doing
before we can really ask and rule out possibilities.
I think just, as a very short thing, I think I completely agree that we're just a little
bit too Earth-centric, right?
Because maybe if we evolve a little further, we're actually going to be fine with the energy
and the resources we have.
We're going to actually manage them, right, because usually colonization or moving out
is because you're running out of resources, you need something else.
And in addition, 75 percent of all the stars out there are small red stars who have a much,
much longer lifetime than the sun so they don't have to go anywhere to find somewhere
And so this is why I love the astronaut program.
That's what I said before.
We have about a billion years on this planet before because the sun, like every other star
gets brighter with time.
It's just what they do.
It's going to get hotter on the earth.
So even without us amplifying the CO2, we can speed the process up, but even if we don't
then in about a billion years it's gonna be way too hot here.
So we going lose the surface oceans with all the models that we're running and so we'd
have to be either a space faring species at that point to go somewhere else to build hopefully
one of these amazing space station that I keep seeing in the science fiction movies
and I really want to live in one of those.
And you could think about a space station being Paris, one London, one New York, and
shuttling in between, right?
I have no problem.
I don't need another planet if that's the case.
But I think a lot of the time, you know, because the Fermi paradox and the Drake equation were
this amazing first attempts to quantify the problem, but I think it's also deeply rooted
in our idea that we won't get our resources sorted out, that we will have to expand to
survive and that everyone does.
And so I'm very much with Susan hopefully that if 50 million year older civilization
or or you know the numbers are staggering.
They could be 6 billion years older than we are, so older than us when the earth was born,
So it's not even something I can imagine, but I do hope, I'm a positive or I'm an optimist
for humankind and civilization.
I hope we get our energy and resources sorted and then we wouldn't have to expand.
We will go and find out because we are curious.
We could travel but we wouldn't have to colonize and therefore this whole idea that you would
spread over the whole galaxy to actually make it yours might not appeal to us because I
think some of us in the audience, right?
If you see a place where you'd love to live, but you see somebody else has built a house
there, I'm not going to go and actually push it down and say, no, I'm here.
And I hope as a species we evolve to that system too and so we have our amazing planet
and oasis in space.
Maybe we don't need to occupy everything else.
I agree with a lot of that.
I mean, I think the one thing is though, this is often an argument I use when people ask
me, well, why do you study things like astrobiology and life and universe out there?
Because it's the way we're going to learn about ourselves and I just wonder whether
part of the motivation for spreading across the universe is you're still looking for answers
about yourself and you may never be able to find all of those by staying at home.
I just, just, just to put that out there.
If we accept that there is life out there.
Let's talk about whether or not that life might be intelligent, whatever that means.
So what does that mean?
I think one of the things that's very interesting about us as an intelligent civilization is
that we construct theories of, of our world and we can, in the like, laws and we can use
those to do really interesting things like launch satellites into space or people into
Um, and so, so, so theories themselves are actually information about the world and they're
information that allows us to do things.
And so that's one way that I actually define intelligence is when you start having things
that, the, that, that those systems actually have knowledge or information that allows
them to generate structures that wouldn't be possible without having knowledge.
There is no possibility that you would have all those satellites orbiting our planet unless
we had a technological civilization with intelligence and knowledge about the laws of physics.
So when we're thinking about looking for intelligent life out there, I think what we need to look
for is things that can't be explained by physics and chemistry alone, but require additional
information in the system to actually generate those structures.
Now, as I'm saying that, I have no idea what the heck that means, but I think that we need
to think about that kind of perspective.
Um, in order to really clarify the questions that we're asking.
So we're, we're at this point in the program where we're going to transition to part four,
which is life in the future.
we have this idea that we're going to make AI alive, and is that an okay thing to think
So what we're seeing on earth right now with the development of artificial intelligence
is a revolution, and it's changed all of our lives.
We're on the Internet.
We have our smartphones.
We'll soon have very sophisticated personal assistants.
I mean in a blip.
When you look at the cosmic scale of things, it's a blip.
We will, you know, within a hundred years, start upgrading our own intelligences to where
we may actually be post biological, we could become cyborgs if you will, instead of carrying
around a phone, it will be in the head, we'll have mobile internet connections, we'll have
enhanced working memories, we'll learn languages quickly because we may just get a new neural
It could look like science fiction.
Well, if that's the trend that we see on earth, people have increasingly started asking what
alien civilizations could be like if life does survive on other planets past its technological
That is, if they don't have terrible problems like nuclear wars or you know, environmental
catastrophes, they may have the opportunity to become synthetic beings.
Intelligence is realized in a lot of different ways as people here appreciate.
The same sort of neural algorithms could be run as Sara knows in a different substrate.
We see intelligence systems that are silicon based, for example, on earth.
So all this suggest to a certain degree that when we're searching for intelligent alien
civilizations, the little green man or ET model, as much as I like Yoda, it's my favorite
That's not necessarily what we want to be looking for, when we're looking for technological
We might be looking for synthetic intelligences that are computroniums the size of a planet.
There are a lot of moral and ethical issues to think about here.
Um, they may not be conscious.
I consider that an empirical question.
It may not feel like anything to be them, if they're synthetic.
We may find out answers to these questions as we develop our own AIs on earth.
That's not to say however the intelligent civilizations are out there.
Um, one thing that didn't come up in response to the Fermi paradox that I thought I think
of is incredibly interesting is the idea of the great filter.
So there's, this is called the great filter argument by the economist Robin Hanson, and
he suggests essentially that, you know, we don't even know how easy it is to find life.
I mean to actually get life kickstarted on another planet because we don't know how really
what to say about the origin of life on earth.
So we actually don't know, given all those exoplanets, how many places are actually inhabited
because we don't know how easy it is for life to get going.
But suppose you do have microbial life on these planets.
Well, how difficult is it to get from microbial to more complex forms of life?
And then from there, how difficult is it to get to intelligent life?
And then from there, how long, how possible is it to survive technological maturity?
And we have nuclear war, superintelligent AI, all kinds of global catastrophic risks
that our civilization faces.
And maybe it's that way for other civilizations, so Hanson suggests there could be a great
filter anywhere at all from the very beginning, from the inception of life on a planet to
highly intelligent life.
So I think these are the kinds of issues which are interesting to think about when it comes
to things like the Fermi paradox.
And, you know, Sara, with the idea of looking for complex systems and these networks, um,
would you consider AI to be life based on, based on that?
I definitely do.
So, so I think that the post biological phase of evolution is really interesting, but people
tend to think it's really different than what we've seen in the history of life so far.
But if you adopt sort of this informational perspective of life, it seems like the natural
consequence of the way life evolves on a planet that if it is increasingly building better
information processing systems, that that would be an inevitable outcome.
And it's not that it's an unnatural one or that it's a bad one.
It's just what happens.
And so I think, I think that we tend to be afraid of these things, but I don't, I don't
think that we should be afraid of artificial intelligence.
I think it's, it's just a part of what we are and who we are and, and in some sense
that those systems will be our progeny in the longterm future and they may be biologically
integrated, they may be entirely artificial, but they are still something that we created
that we will send out into the universe.
And so something I find really intriguing about this discovery of alien life is, is
that it might be very likely that the things that we discover are artificial, but also
what's discovering them is artificial because we don't usually send humans out into space.
We're sending machines and we're probably going to be sending machine learning algorithms
and AI out into space.
So really when we're talking about making alien contact, it might not even be biological.
It's going to be our artificial systems making contact with other artificial systems.
And will they consider ours alive?
They might, I don't know.
Hopefully.It reasons some interesting ethical questions.
It's really interesting, yeah.
So maybe just to inject,
Be a little contrarian.
So as I'm sitting here listening to this, what I'm, what I'm realizing is, you know,
in a lot of these discussions to do with things like the great filter and also the Fermi paradox
and spreading around space that there seems like there's this implicit assumption that
species remain the same.
And, and you mentioned, you know, earth in a billion years when the sun has gotten a
bit hotter and our planet has this runaway greenhouse and we're all dead, we want to
Evolution will have taken care of that.
Evolution itself might be the filter because we're not static, no matter how much we might
imagine ourselves, you know, a million years in the future, humans in the future, we will
not be the same biological entities that we are now, neither will our machines be the
same machines that they are now.
Evolution is perhaps the most unstoppable force in the universe.
And so I just wonder, you know, if we're talking about life in the future, um, you know, it's
going to be totally different than anything that exists right now.
I think we can say that with certainty
even as us.
We won't be around.
Even despite our best intentions.
We can, we can solve our energy problems, we can, you know, write records of everything
we have, literature and so on.
Biologically, I, I'm not sure it's either possible or desirable to hold our biological
evolution and evolution, Darwinian evolution happens at multiple times scales.
It's happening right now, like that.
It's also happening over millions of years and it's very, very difficult to see where
So I think, you know, part of what's happening is we're kind of, we're getting to this point
where, well, humans in the future, we wouldn't be humans anymore, we will be something else,
But that doesn't mean we shouldn't be, protecting what allows us to survive here.
Because the times go maybe very long, but this may also have something to say about
the Fermi paradox, about the great filter that it's actually evolution that, that just,
that aggressively expanding species.
It takes it still 10 million years to get anywhere interesting in the galaxy.
By that time, it's done that.
It's not the same species.
Just to that point, there is this like intrinsic need to be the same.
But like, but the thing that always strikes me as really interesting is we aren't physically
the same as we were like 10 years ago.
I mean, literally like the atoms in your body are not the same atoms.
I'm not for sure though.
So what we think about as being the same is very subjective.
Um, and so, so I think, I think Caleb's absolutely right that we are continually evolving systems
and we're systems that were information is constantly restructuring us.
So, so the reason that you're still, you know, a coherent entity 10 years later, even though
you don't have the same atoms is because your body is constantly rebuilding itself.
And so an evolution just does that on a different timescale.
It builds new systems from the previous systems and that's totally fine.
So I think, I think our definition of what we are needs to be expanded and that's one
of the reasons that I like this idea of thinking about life at a planetary scale because we
are all life on earth and it's very integrated as you were describing before, we can't really
take out a piece of it and say it's separate.
Um, and so when we're thinking about the evolution of life on this planet, we have to think of
that entire planetary life evolving.
And we're definitely gonna evolve into something else in the future and probably AI is going
to be tightly integrated with, that and we don't know what that's gonna look like, but,
but it's not not going to be us.
It's still going to be the same lineage.
I'd like astrobiologists so much because you’re so laid back about the next 200 years because
you think of everything in these grand timescales.
But I think we have to remember that, um, we right now have a lot of issues with emerging
technologies that urgently need to be navigated so that we do press on and that we can make
decisions about how to design minds, if you will.
So Caleb, you talk about it all being a matter of evolution in a Darwinian sense.
But even Richard Dawkins said recently in a film that we were both in called Super Sapiens
when it comes to artificial intelligence and brain enhancement, it is now the era of intelligent
We are the designers,
Which is why I think the idea of being earthlings is so important.
If we're looking at ourselves as this planetary system, it's not just me deciding.
It's not just you deciding.
It's as, as this the inhabitants of this planet, we have to decide how are we going to work
together for that future that I'd like to think, you know, my son who's only 15, he's
got his life to live and you know, and yeah, there's this grander scale of time that where
we all change and all that happens, but I want to know that, you know, as human beings,
we're going to figure out how we survive here too.
I mean, it's a bit of a stretch, but this is another motivation for finding other life
in the universe.
This story may have played out many, many times before.
And if we ever got to the point where we could interrogate, maybe not interrogate necessarily
in the sense of a conversation,
On a surgery table, lets not do that
but interrogate from afar by observation, whether it's understanding even the detailed
chemistry of a planetary atmosphere tells us what mistakes they made, the pollutants
in the atmosphere and so on.
You know, there are other stories out there potentially that could tell us how to do things
and actually make it through this augmentation period or make it through a filter.
You know, there may be other places where it worked and places where it failed and we
could learn from that too.
That's a stretch, but
I think Nicole, in the beginning of this, you asked why we should care, for example,
if we don't find life out there, what, what our reasons would be?
And I think Caleb just touched on one of those, uh, by finding other planets like ours out
there, we'll find some that are older than us.
And even if evolution is different, let's say some will be in a further evolutionary
stage than we're.
And that is the only way that allows us to glimpse in our potential future.
And the way I usually talk about this is like, for example, we see all older earths have
a lot of SO2 in the atmosphere.
Comes from volcanoes.
We can’t breathe it.
That doesn't mean it will happen to the Earth, but it wouldn't mean that it would be intelligent
for us to develop a technology to filter it out just in case this is something that happens
to all earths.
And so even if people don't about whether we’re alone in the universe, what's coming,
being as informed as we can, whether we become synthetic or not, taking as good care as we
can of our own planet, I think is the imperative that right now we are guarding this on it
and we are responsible for it.
I, I love that as kind of a closing note because when we think about exploring further off
our planet, finding or not finding what we consider life to be out there, we know from
what we've done already, even in low earth orbit and as human beings only getting to
the moon so far, that we have learned a lot about ourselves and about how, how we do those
things to improve life here on Earth.
But I want to thank all of you for a really, really impressive conversation.