Cosmic Queries – Life on Exoplanets with Sara Seager

Hey, you wondering how you can invest in yourself and work towards a goal that will last?

Rosetta Stone makes it easy to turn a few minutes a day into real language progress.

You've heard me talk about Rosetta Stone in the past, and you know that I love the anytime, anywhere bite-sized lessons that allow me to go ahead and continue to learn Spanish so that I can know exactly what my mother-in-law is saying about me.

Maybe you're gearing up for a trip to another country, or maybe you're going to reconnect with family roots.

Or maybe you just want to impress people with the fact that, yeah, you know another language.

Well, now Star Talk Radio listeners can grab Rosetta Stone's lifetime membership for 50% off.

Visit RosettaStone.com slash StarTalk to get started and claim your 50% off today.

Jas la order, mi amigos.

Rosettastone.com slash star talk.

You ever walked around a neighborhood and wish you could see inside somewhere that was available for rent?

Well, let me just give you a tip.

Don't climb up on the ledge and look in the window.

People will call the cops.

Well, maybe you've walked past a place for rent and you wished you could peek inside.

Maybe even explore the layout, envision the natural light streaming through the windows, or plan where your vinyl record collection would go.

Well, at apartments.com, you can.

With tools like their 3D virtual tours, you can see the exact unit you could be living in at all from the comfort of your couch.

And if you end up wanting to see it in person, you can book a tour online without having to speak to a leasing rep.

Really envision yourself in your new home with apartments.com.

The place to find a place.

Hey, Star Talkians, Neil here.

You're about to listen to an episode specially drawn from our archives to serve your cosmic curiosities.

Check it out.

Welcome to Star Talk,

your place in the universe where science and pop culture collide.

Star Talk begins right now.

This is Star Talk.

I'm your host, Neil deGrasse Tyson, your personal astrophysicist.

And this week is a Cosmic Queries Edition, the always popular Cosmic Queries.

And the topic, the always popular search for life in the universe.

And I've got with me is my co-host, Matt Kirschin.

Matt.

Hey.

Hey, Neil.

How you doing?

I spent all day yesterday trying to memorize the name of your podcast.

It's probably science.

Did I get it right?

I was always mangling.

I stumbled in my efforts there.

I found a podcast called Sometimes, or Mostly Science.

It's a whole other podcast.

Oh, we hate them.

No, we've got a running rivalry with them.

It's going to be totally have rivalries.

I got to make sure I get your stuff right.

Probably.

It'll come to violence at some point.

Probably violence.

So I know a little bit about the search for life, but not as much as our guest today.

Our guest today is Sarah Seeger.

Sarah, welcome to Star Talk.

Thanks for having me today.

Yeah.

So Sarah, let me get your full

title up here.

So you're professor of aeronautics and astronautics, physics and planetary science at MIT.

Is that what?

No, they left out a few categories.

No, no, no.

It's because exoplanets and the search for life is an incredibly interdisciplinary topic and it draw draws upon all those different fields excellent but between you and me can i call you're a planetary scientist right that's really yes yes i mean my home is really in astrophysics okay so you can call me an astrophysicist or a planetary scientist or both

in the club so uh i guess the search for life in the universe has to necessarily include the search for exoplanets, right?

Right.

They go together.

But is that part of our bias?

Not necessarily.

We do.

I mean, we're definitely terra-centric.

We definitely are narrow-minded, but at the same time.

Like Earth-centric.

Yeah, like Earth-centric, you know, and on Earth, we believe that for the origin of life, we need a place for ingredients to concentrate.

And it's hard to imagine ingredients just, you know, concentrating in the vastness and that low density of outer space.

Okay, so this concentration thing, I think, is undercelebrated out there.

I mean, in the public,

people, we take it for granted that we have rocks and buildings and mountains and people.

And

for it in our

greater universe, nothing is to get.

It's mostly empty.

And where it's not mostly empty, it's highly rarefied.

And so planets are really special places.

Is that fair?

They are

very special because they do concentrate complex molecules.

They concentrate elements, nutrients, and everything we need.

Am I right in thinking they are substantially less special or at least less rare than we thought they were even five, ten years ago?

Yes, actually.

We are slowly making ourselves less and less precious, less and less special.

No, Sarah, it's okay to know that.

You're not just supposed to tell people that.

I think that's nice about science.

I like the fact that scientists sort of switch between going, you're incredibly special and you're not special.

Well, we do.

We love thinking back to the Copernican revolution, where before Copernicus, the model of the universe was that our Earth literally was at the center of the universe.

All the planets and the sun and the stars apparently all orbited Earth.

I think I've heard, is it Andrean describe this sequence?

Some combination of her and the Carl Sagan camp referred to it as the sequence of great demotions

for whatever we imagined ourselves to be.

Plus, there was some rebuttal to that.

I forgot the fellow's name, but he wrote, I think, convincingly that the idea,

that the idea that we are in the center is not necessarily an elevated place if heavens are above us.

Right.

So the center could be the slag heap of where everything collects and your ultimate goal is to ascend from that to greater places.

So, but in either case, the location was unique, I think, that you think about it.

So in his his mind, we're like the plughole of the universe.

We're sort of a terrain.

So Sarah,

was it natural to transition from exoplanet discovery to the search for life?

Or did someone have to sort of nudge you or was it just obvious as the next thing to do?

You know, every scientist is different.

And I've sort of been the random walk type of scientist, like work on a problem and see a more interesting problem and then move over slowly.

If you like the dog being distracted by the squirrel, you know, squirrel?

Yeah.

You can't keep it.

But I think when you started out

in the late 90s,

we didn't know many exoplanets.

And even those that we did, it was fun to think of aliens on them, but there was no research program.

there yet.

So it seems to me you were there at the birth of this, if not having birthed it yourself.

Yes.

And in fact, but just to go back even further before my time, perhaps even before yours, but in the decades past since the.

Even before Neil.

There is no such thing.

No, okay.

Well, you know, what's interesting is if you look back, like even, you know, just after

the time of Sputnik, like in the early 1960s, there's actually a report from a think tank.

kind of company and it actually talks about planets and exoplanets and the chance for other earths and even in the decades after that you know there were always studies on how would we go about finding another earth and so when exoplanets was born in the mid-1990s and yes i was there i was a graduate student working on exoplanets at the time you know they were hot jupiters they were not suitable for life in any way but slowly those two things came together you know all the past decades of thinking about earths then switching gears to the hot giant planets.

And so the thought of finding Earths and life, it was kind of always there in the background, even though it might have been a bit of a stretch.

And just to be clear, the Jupiters that you're referring to being hot was it was easier to find really massive planets first compared to low mass planets.

So you're going to find a Jupiter first and we've, and they're hot because, cause why?

Because they're very close to the star, so close to the star that as heated by the star, they're just hot.

Okay, so the Jupiters, but they didn't look like our Jupiter.

So there again, we were not.

So we

thought we were representative of the universe and we're not i mean at least our solar system right right we always expected to find a jupiter where our jupiter is which is you know five times further from our sun than earth is and instead we found jupiter mass objects within a few you know few day period orbits of the star so even our bias that which shows up every day in race relations and sexism it even shows up in astrophysics just it did yeah and you know the funny thing is is just to take that a level further when we people first found these hot Jupiters so close to the star, we just assumed that they had the same albedo, the same reflectance properties as Jupiter itself.

Jupiter is quite bright, you know, you see it in the sky because it's got icy clouds.

And we couldn't see Jupiter in reflected light.

And with a little more thought, we realized, wow, these hot Jupiters, they're incredibly dark.

They're very absorbing.

They have no reflective clouds.

Most of them.

Wow.

Okay, so they're not only,

so they're big Jupiters that don't look anything like Jupiter.

That's what you're saying.

Like, I mean, yes and no.

They don't appear like their atmospheres aren't like Jupiter, but they're kind of bulk composition.

They're mostly made of hydrogen and helium.

That part's the same.

All right.

So if you come to this as an astrophysicist, planetary scientist, and now you want to think about life, you got to start knocking on the doors of biologists.

So when did all that happen?

Remarkably, it really, it started happening for me when I had my first staff position.

I worked at a place called the Carnegie Institute of Science, and I was in Washington, D.C.

And it's quite interdisciplinary there already.

And they were already part of working on the somewhat new field back then of astrobiology.

So I started interacting with biologists there.

And the funny thing was, is I got a postdoc there and I signed him up to work with me.

And it literally took us like nine months before we could even understand each other because our language was so different.

Yeah.

So you need the coffee lounges, you know, between

at the intersections of departments because otherwise we just live in our stovepipes and discoveries go un un

unattended to it's true it's true and later on i attended an astrobiology conference and i met a remarkable person there who became one of my closest colleagues and so then through him him being a biologist i was able to learn and accrete more more collaborators and so i mean you have a fascinating story i only recently learned that you've actually uh collected that together in a in a kind of a memoir, the smallest lights in the universe.

So congratulations on that memoir, published by Crown in 2020.

And because we're all distracted by big explosions and big lights and big things, but maybe the smallest lights in the universe, I guess these are the exoplanets,

or it could be a metaphor for other things in the book, that it's just call attention to other

previously underserved domains of the cosmos.

Thanks.

Yeah.

So, so let's get straight.

Let's get straight to this.

What is life?

You know, in exoplanets, we have a good excuse for completely avoiding that question.

And we do, we do.

I'll run it by you.

I'll run it by you.

All right.

Because we have telescopes and we can see atmospheres of other planets.

We're hoping with our next generation telescopes to see atmospheres of small rocky planets.

And we're going to look for signs of life.

by way of gases that might be attributed to life that have accumulated in the atmosphere.

So we prefer to think about what life does.

Life metabolizes and it may give off gases during that chemical process of metabolism.

So, we conveniently sweep that under the rug and we just talk about what life does.

And you sweep it under the rug because you can't do anything about that question anyway.

We can't do anything about it.

And it's just a question that no one wants to agree on what the answer is.

So, you sweep it under the rug and say, Let's do what life,

let's observe what life does.

So, you're the atmospheric gases equivalent to the people who study

animal poop, for example.

It's things that life does, even if you're not studying the life itself.

That's right.

Not to equilibrate your study with the study of feces.

And actually, Neil, that has never been done before.

So that is brand new.

It's a brand new analogy.

Atmospheres on planets are kind of the...

animal remains of the galaxy.

Well, the gaseous effluences, I guess.

Yes, it's actually, that's a great way to look look at it.

So, Sarah, but

clearly, there are gases out there.

And I want to get to the Q ⁇ A because Matt has them lined up, and I don't want to lose any time on that.

But clearly, there's some gases.

Let's take methane, for example,

that we know is the byproduct of life, not all life, of course, but some bacterial life on Earth.

We know that.

So, now let's look to another place like Saturn's moon, Titan.

Oh my gosh, it's completely covered in methane.

So it must be teeming with life.

So we're, but it's not.

So where do, how, what?

Yeah, that's the single most biggest problem, that we need to be able to see other gases in the atmosphere and put the gas in question in context with what else is there.

But even doing that will be, it'll still be hard.

It'll be very like a forensic crime scene, you know, how do we pick out what is really life, what is really not made by life?

So, the gases you list that are the products of life are necessary but insufficient to prove that there's life.

Yes, actually.

And that is the sort of, let's call it the dirty secret of the whole field is that we'll never be able to prove it.

So, sort of in forensic crime scene terms, you sort of got to distinguish between blood that was caused by the crime and blood that was just previously existing, sort of decorative blood in that room.

Precisely.

Just blood that someone had put there that would just naturally be there on the walls in a slide.

Yeah, the normal blood that exists in the room.

I'm sure Sarah is going to put that analogy in her next research paper.

Yeah.

Right, right.

Just add an equation and that's all science is, right?

If it's in an equation, it's legit.

Yeah.

And so on our Earth, we have methane produced by life, by bacteria, you know, by cows, but we also have methane coming out of mid-ocean ridges.

So in a lot of cases, it is definitely ambiguous.

And methane is natural gas that we have in our stoves.

And I'm pretty sure what's coming out of your stove is not cow farts.

It's come from another location on Earth.

Okay.

So, Matt, we have a couple of minutes left in this segment, but let's see if we can squeeze in a question.

Okay, great.

Well, this one, I love the questions that come from our younger listeners.

This one comes from Carrie Jenkins, an eight-year-old fan.

Eight.

How long, I know.

Eight.

How long do you think it'll take for us to find other life in the universe?

Yeah, how close are we, Sarah?

How many, how many more years?

What do we got here?

Well, we actually will have, we like to say we'll have the key.

I'm not purposely trying to evade all your questions, honestly, but I would like to say that we will have the capability to find signs of life very soon with the launch of the James Webb Space Telescope.

But whether we find life, that really depends on what's out there.

You know, if every planet has life, if life is extremely common, life that makes gases.

So if you want a concrete answer, I could say anywhere between two years and

30 years, let's say.

Okay, so this would be the life, the usable life expectancy of the James Webb Space Telescope.

Well, I was putting the James Webb, whose nominal life expectancy is five years, maybe 10.

I was thinking of future telescopes beyond the James Webb.

Okay, and possibly missions to the icy moons of Jupiter,

where there might be life beneath the surface or even life beneath the surface of Mars, right?

I mean, why not?

You're not looking for that life, but you got other people, top people doing that as well.

Right.

Okay.

So we might find life or definitely know there isn't life as we know it in the lifetime of this eight-year-old girl.

Well, maybe this eight-year-old girl will carry the torch.

If all the searches we're doing now are exhausted, maybe she'll be the one to think of the next new idea.

Oh,

maybe you all aren't clever enough, and we need her to come along and solve all the problems.

There you go.

The best business to business marketing gets wasted on the wrong people.

Think of the guy on the third floor of a 10-story apartment block who's getting bombarded with ads for solar panels.

What a waste.

So when you want to reach the right professionals, use LinkedIn ads.

LinkedIn has grown to a network of over 1 billion professionals and 130 million decision makers and that's where it stands apart from other ad buys.

You can target your buyers by job title, industry, company, role, seniority, skills, company revenue.

So you can stop wasting budget on the wrong audience.

It's why LinkedIn ads generates the highest business to business revenue on ad spend spend of all online ad networks.

Seriously, all of them.

Spend $250 on your first campaign on LinkedIn Ads and get a free $250 credit for the next one.

No strings attached.

Just go to linkedin.com slash Star Talk.

That's linkedin.com/slash Star Talk.

Terms and conditions apply.

Huge savings on Dell AI PCs are here and it's a big deal.

Why?

Because Dell AI PCs with Intel Core Ultra processors are newly designed to help you do more faster.

It's pretty amazing what they can do in a day's work.

They can generate code, edit images, multitask without lag, draft emails, summarize documents, create live translations.

They can even extend your battery life so you never have to worry about forgetting your charger.

It's like having a personal assistant built right into your PC to cover the menial tasks so so you can focus on what matters.

That's the power of Dell AI with Intel Inside.

With deals on Dell AI PCs like the Dell 16 Plus starting at $749.99, it's the perfect time to refresh your tech and take back your time.

Upgrade your AI PC today by visiting dell.com/slash deals.

That's dell.com/slash deals.

I'm going to put you on, nephew.

Hi, Don.

Welcome to McDonald's.

Can I take your order?

Miss, I've been hitting up McDonald's for years.

Now it's back.

We need snack raps.

What's a snack rap?

It's the return of something great.

Snackrap is back.

Hi, I'm Ernie Carducci from Columbus, Ohio.

I'm here with my son Ernie because we listen to Star Talk every night and support Star Talk on Patreon.

This is Star Talk with Neil deGrasse Tyson.

What more do you have, Matt Boris?

Also, by the way,

we should mention that our guest today isn't the only one with a new book out.

And you've got a book based on Cosmic Queries that has a chapter that talks about the search for light.

Oh, yes, indeed.

So thanks for mentioning that because I almost forgot.

I probably wouldn't have forgotten by the end, but there's a book called Cosmic Queries.

Because this format was so successful, we said we've got to do more than just put it out there as a podcast.

So there's a book called Cosmic Queries that takes all the biggest questions, including this one.

And much of Sarah's research that informs this field is contained in that chapter.

And so in a celebration of Cosmic Queries as a thing and the search for life as a sub-thing of the bigger thing, we've got Sarah Seeger.

So, Sarah, thank you again for being on Star Talk and for checking in for this.

So, Matt, what do you have for us?

Well, I've got to do another Cosmic Query question from another young patreon listener.

This comes from Violetta and Violetta's mum, Izzy.

Violetta is a 12 and a half year old astrophysicist here in Birmingham, Alabama.

12 and a half.

When you're young, those halves are important.

And

asked Professor Seeger, i want to know firstly what exactly are biosignatured gases and secondly what biosignature gases would earth give off that would be detectable by extraterrestrial life who might be looking for inhabited planets like ours perfect question yes sarah yeah or would ets not need to look for our biosignature gases because our existence would be pretty obvious because duh space junk

yes well a biosignature gas is a signature of life it's a gas produced by life that can accumulate in an atmosphere of a planet to a level that we can detect with our telescopes.

You know, I love to imagine, you know, there are intelligent aliens on a planet orbiting a nearby star, and they have the kind of space telescopes we're building or hoping to build.

They would look at our Earth and they would definitely see a very strong biosignature gas, and that's oxygen.

And oxygen fills our atmosphere to 20% by volume.

But without plants, without photosynthetic bacteria, we would have literally virtually no oxygen.

So if all the plant life went away, you know, walked off the earth today, how long would it take for our oxygen supply to sort of drop to zero?

And why would it drop at all?

Why wouldn't it just stay there?

Well, we also have bacteria that make oxygen.

So I'm not sure, you know, what the division between.

So no, no, no, just take away everything that's making oxygen.

Take everything away.

And so now we've got 20% oxygen.

What happens to it?

Well, what happens to it is oxygen is a highly reactive gas and it will just react away with other molecules in the atmosphere, with lots of things on the surface, you know, with gases coming out of vents and volcanoes.

And that oxygen just won't be there.

How about

how much time would that take?

Would it happen like next week or in a year?

No, no, it wouldn't happen next week.

It probably wouldn't happen in a year.

It's probably more like thousands of years

or more.

Okay, so we, so we, if we kill all the life, the oxygen-producing life, we can still live out our lives with oxygen.

If subsequent generations, it'll suffocate.

Yes, probably we could live without our lives.

Okay, so what you're saying is, even though this 20%

has been stable over the history, mostly stable, it's not actually

a stagnant number because we are constantly producing it and constantly removing it, and it just happens to be balanced at this number.

Is that a fair way to say it?

That's a fair way to say it.

Okay, okay, cool.

All right, all right, Matt, give me another one.

All right.

This This comes from a Grumsetuff.

One word.

I hope I'm pronouncing that even close to correctly.

Whatever you did, it's better than what Chuck does with names.

Chuck can't pronounce anything.

What is your most optimistic explanation of the Fermi paradox?

I like that question.

Oh, yeah.

I think we all have our favorite answer to that one.

Well, tell me what it is first.

The Fermi paradox is the idea that if, if there is intelligent life.

that can harness energy and get in spacecraft and journey beyond their planet, that they should have colonized the entire galaxy by now.

Because once they can get to one planet and colonize that, they can just keep going.

And so the Fermi paradox is summed up by the question, where are they?

So what you're saying is in the lifetime of the galaxy, it doesn't really take that much time, if you're intelligent by our measures, to build spacecraft and start traveling to planets, even if you can't travel at the speed of light.

Right, right.

That over time, you would eventually reach planets and colonize.

Okay, so, all right, so where are they?

Okay, so there's the explanation I think is the real one, and then there's the one that I hope is the real one.

So, Matt, Matt, her explanation would be they're already here.

Yeah,

I like that one.

Yeah, that's the funnest answer, but go on.

Shut up, we're not meant to talk about that.

So, you know, one answer is that it just takes too much energy.

Like, we as humans, we know now what it takes to get in a spacecraft and go somewhere.

That's a lot of resources.

So, perhaps they're they're just not

doing that.

There's another answer that the intelligent civilization will unfortunately and inevitably self-destruct.

They'll destroy their planet.

They'll kill each other.

They won't ever reach.

Would that be the definition of not being intelligent?

Yeah, well,

it would be.

My explanation that I love is: I'll put it to you this way.

Just imagine an ant, an ant colony in your house, you know, which you might have or your apartment.

And the ants, they appear kind of, you know, dumb, but they're somewhat clever, right?

Because they have a society and you see them doing like a reconnaissance.

But just to be clear, just to make sure we're all on the same page, by an ant colony, you mean like one of those ant habitat module things where you can see.

No, I just mean it could be them.

It could be that.

ant colony habitat or it could just be the ants like in your house like you might have just ants in the house

yeah ants in the house and i don't know if you've ever had this but you'll see like a few of them kind of looking around and they might come across like a piece of cat food on your counter or something.

And then shortly thereafter, you have a huge stream of them and they're all coming to get this cat food in like a little river.

Well, you can mess them up if you like wipe away their trail for a moment.

They kind of get lost.

But I want you to imagine, you know, Neil, Matt, having a conversation with those ants.

Like tell them about the universe.

Tell them about the Hubble Space Telescope and the vastness of the number of stars and galaxies.

And tell them about calculus

and geography.

Yes, yes, yes.

So what I love to imagine is that these, to these intelligent aliens out there, that we are like the ants.

Like, why and how would they contact us?

Okay, so Matt, Sarah's bumming us out.

Now we're first we're insignificant.

Now we're just plain stupid.

Well, also, I think it is worth pointing out there are, there are different, I mean, like Sarah was alluding to, there are very different types of intelligence.

And, you know, I've been to university.

You've both spent a lot more time in academia.

We've all met people who are incredibly smart in specific ways and otherwise idiots.

Okay.

So, you know,

maybe they have the ability to travel across galaxies, but then not the ability to not shoot themselves within a very short amount of time.

So the official answer is the official answer to the Fermi paradox.

Where are they?

They think we're idiots.

Either they think we're idiots or we think they are for having self-destructed before they could get here.

Oh, there it is.

Touche.

Touche.

All right.

So Matt, give me some more.

So along the lines of interacting with other civilizations, Eric Gross asks, let's say we discover proof of life not in our own solar system, but on some distant celestial body.

Would there be any meaningful scientific value of the discovery or opportunity to expand upon the knowledge?

It may, of course, have broad societal and emotional effects, but would science practitioners have any real hope of gaining more information about life forms that are at a minimum of 4.3 light years from Earth?

I love that question.

And Matt, who asked it?

That was Eric Gross.

Eric Gross.

Okay.

Yeah.

So, Sarah, I love that question because generally when we think of scientific discoveries or advances, we think, okay, in five years or 10 years, engineers will get a hold of it and they'll make some new device and we'll all be living better and differently.

And so

life somewhere else that you can't actually have a conversation with, even if it's intelligent, are you getting the secrets from that?

I mean, what, if you can't, or can you?

Are we missing something here?

It's such a great question.

I mean, we are so wrapped up in the emotion and the excitement of the journey of exploration and of being the first who can try to find out what's what's out there.

So in a practical sense, not really.

I mean,

we're not doing this to find anything practical.

That said, wouldn't it be amazing if there is life, intelligent life on the nearest star system four light years away, and we could have a very slow conversation.

Very slow.

We could imagine.

No witty repartee there.

Right.

Send them a message and, you know, four years later, you'll get their message back, and we could exchange ideas about technology.

So if we wanted to be practical, like that's probably the most practical avenue.

So,

but in terms of biology, unless we learn from them through these radio signals, what their sort of biochemistry is like, we wouldn't get to compare DNA or if they have DNA at all.

You wouldn't be able to do any sort of in situ kind of comparisons to advance biology on life, I would guess.

Is that correct?

Right.

No, that's correct.

That's correct.

Yeah, but I don't want to sound like who was that philosopher

150 years ago who said the stars, they're just lights on the sky and we can know, you know, how bright they are in the location, but we will never know what they're made of.

Right.

And think about this.

Like, we're just here now.

Imagine a thousand years from now, you know, 10,000 years from now.

Right.

We may have a way to get to this.

Imagine if there's life on intelligent life on that planet and we do like a sample return.

We fly something by, they send something up.

We grab it.

we you know gravitational slingshot around their star and we come back okay so uh so all right i'll just think a thousand years from now rather than okay next week okay

well what you just said those that answer segues quite neatly into this question which i like and i'm going to combine two different questions from both Tom says, who asks, what forms of communication are most likely to be able to cross between the stars?

And

Trumpet Womb, who says how do you think we will overcome the language barrier if we ever meet another sentient life form i love it and and sarah remember that movie um arriving arrival so i got in in trouble for and i i i knew i was going to get in trouble for saying this i said in the movie arrival they brought a physicist and a linguist to try to communicate with the alien when they should have brought an exobiologist and a cryptographer and i got so much shit from the linguists out there because this is their one time to appear in a movie.

And there I am just dissing them.

But what is your opinion about how we would actually communicate?

I mean, I love that movie.

I love the concept that it may be so difficult that

we may not find a way to communicate.

Okay, so Matt, she just swept that one over.

You hear that one?

She

doesn't like any of my answers.

She's sweeping it.

I don't know how big her rug is in the middle.

But how about mathematics?

How about symbology?

How about, I mean,

I like all those answers.

You're okay with them or not?

I like it.

I like it.

It would have to be something that is fundamental in a very mathematical way.

I agree with that.

Because math apparently applies across the universe.

So if they discover something that is cosmic universal, it'll have to be the cosmic universal things we discovered as well, I presume.

Right.

So I wonder, so I think one of our greatest triumphs is the periodic table of elements.

If we can like show that to them and see if they have a version of it.

Because there'd be a lot of pantomiming initially, I would guess,

before anybody actually communicated.

So

it is funny that aliens often just spoke English, you know, in the movies.

Right, right.

That's why the arrival is so great.

It's such a great movie because it's the first time they have these beings that have no way to really, really interact with us.

Right, right.

Right.

So, Matt, give me one more question before we wrap up this middle segment.

I will do.

And for the people who are watching the video rather than just the audio, I apologize for the other life form that keeps walking across my lap while we're trying to record.

I have no way of communicating with him.

Well, so I'm also going to combine these two questions because they're in similar themes.

So, Rob Carter asks, when searching for life on other planets, is there a priority of what type of life you look for?

For example, would a land-based life form take precedence over an aquatic species and so forth?

And then Jonathan R.

Brown asks, carbon-based life on Earth developed in the oceans and diversified exponentially from there, spreading to land and beyond.

Life on other worlds may develop from a different elemental base and begin on land or in other environments.

Could ET life be too alien for us to recognize as life?

And what is the baseline?

Tron Aries has arrived.

I would like you to meet Ares, the ultimate AI soldier.

He is biblically strong and supremely intelligent.

You think you're in control of this?

You're not.

On October 10th.

What are you?

My world is coming to destroy yours, but I can help you.

The war for our world begins in IMAX.

Tron Aries, rated PG-13, may be inappropriate for children under 13.

Only in theaters October 10th.

Get tickets now.

This episode is brought to you by Progressive, where drivers who save by switching save nearly $750 on average.

Plus, auto customers qualify for an average of seven discounts.

Quote now at progressive.com to see if you could save.

Progressive Casualty Insurance Company and affiliates, national average 12-month savings of $744 by new customers surveyed who saved with Progressive between June 2022 and May 2023.

Potential savings will vary.

Discounts not available in all states and situations.

I'm going to put you on, nephew.

All right, um.

Welcome to McDonald's.

Can I take your order?

Miss, I've been hitting up McDonald's for years.

Now it's back.

We need snack wraps.

What's a snack rap?

It's the return of something great.

Snack wrap is back.

All right, so Matt, we left off with a brilliant pair of questions.

Tell me the two names who asked it again.

Yes, that was Rob Carter and Jonathan R.

Brown, and they were both asking about the types of life forms that you might find on other planets, whether land-based, aquatic, and so on, and whether we'd even be able to recognize those things as life.

Yeah.

Yes, well, we won't have a chance to see that life.

We'll only see what life does.

We'll see the byproducts of that life.

Because the telescopes aren't good enough yet.

Right, right.

We'll only see the planet far away.

We won't even see it in some cases.

It'll be a pale blue dot, or we'll just see its atmosphere as backlit by its stars.

So we won't see the animal.

So the point is, when you study the chemistry of the atmosphere, it's a remarkable feat of...

of observational astrophysics because the light from the star behind it passes through the transparent atmosphere, and then the molecules leave their fingerprint, and that's what you're studying.

Right.

That's the way we're studying exoplanet atmospheres today.

So we're a long way off from you watching something wave to you in the telescope lens.

We are, but you know, funnily enough, it doesn't stop us.

Yeah, I do have that answer.

Well, I was going to say, it doesn't stop us from speculating about what life might be like.

I want you to just imagine for a moment, because there are exoplanets are so diverse.

They're different masses and sizes.

And we're imagining their atmospheres are all different.

Imagine a planet where the atmosphere is so massive and heavy that it's a similar density to water.

So imagine you have a water ocean, and above that is a heavy, dense atmosphere.

You could imagine things like flying fish that can just move between the atmosphere and the water because it's the same

density.

Whoa.

Okay.

Now

we love to imagine a planet that is somewhat dark because of a massive atmosphere.

And we like to imagine this idea of birds with giant wings that are photosynthetic, that the wings are like giant plant leaves.

They can fly up to where there is sunlight and gain energy from the sun that way.

Sarah, that reminds me, some science fiction writer, forgive me for not remembering, there was a punchline in it where the aliens come to the earth, they see what we all do here, and then they return to their home planet and they report on what they discovered.

And they said, they're all made of meat.

And because we basically eat each other, right?

Life eats other life unless you're a plant, in which case you eat sunlight.

Right.

Wow.

So, I mean, just think about that.

So if you are a bird that has photosynthetic wings,

then to eat, like you just said, you just go to an altitude where you get the sunlight and then come back down and you're not killing anything for your survival.

But then you would presumably be

prey for whatever is in the lower levels because they aren't accessing that sunlight.

You'd want to make sure they're photosynthetic too, I think.

But imagine a whole world where that's the case and they come visit us and we have all these slaughterhouses and not just us, other animals eat other animals.

And this would look like a really bloody, nasty place to them.

I mean, you guys ever think about that?

No, no, but it sounds pretty scary.

Okay, so tell me also about a carbon-based life.

How important is that?

Yeah, because Sam Couch actually asked this specifically while we're doing that.

Sam asked,

is it possible to have life elsewhere that is not carbon-based?

And if so, what would that look like compared to carbon-based life?

And what would be the requirements for that life to survive?

Yeah, there really hasn't been a lot of solid work done in that area.

It's really hard to construct, you know, a biochemistry of like a completely different type of life out there.

We're not sure if silicon-based life is even really possible.

We think silicon, you know, a lot of our silicon here on Earth, for example, it's locked away into rocks and there's just not a lot of silicon.

We think silicon compounds are often they dissolve in water too easily.

So, I think the jury is still out on that one.

Okay, so even though silicon makes the same families of molecules as carbon does, because they're top and bottom to each other on the periodic tables, as we learned in high school chemistry, that they'll all make the same kinds of molecules.

But you're saying the other properties of silicon molecules make them wholly different from what carbon is giving us.

So,

yes, so our search for life is justifiably carbon based not to put words in your mouth but that's kind of what you're saying yeah you said it well that's right okay matt did you she sweep any of that out of the way no i i think that rug is fully lifted and the items underneath are exposed to the elements

and all right so matt keep going all right okay this one this one's pitting host against guest here josh v asks Dr.

Tyson has spoken in the past Star Talk episodes about the idea of Goldilocks zones being antiquated at best and possibly the wrong approach to searching for life.

What is Professor Seeger's opinion on the use and definition of Goldilocks zones as it applies to what galactic locations are prioritized in searching the vast cosmos?

Wow, actually, this is one where Neil and I agree actually.

So just to go into some detail, the habitable zone, it's a good construct, the Goldilocks zone.

It helps us think of where we should be looking for planets.

But in reality, I think it really depends on the individual planet.

Like, I want you to imagine a planet that instead of having an atmosphere like ours that is mostly nitrogen and it has a good amount of oxygen, imagine a planet that has a hydrogen atmosphere dominated by hydrogen.

Did you know hydrogen is a nasty potent greenhouse gas, way worse than any of the gases we have on our planet Earth?

So a planet with hydrogen, it turns out it could still be the right temperature.

far outside to what we think of as this traditional Goldilocks zone because it has such a powerful greenhouse.

And they wouldn't call it nasty.

They would be thankful for it.

They would need it.

Yes, they would need it.

Right, right.

Right, right.

So I like to think of habitability concept as being, you know, planet independent, not your location in the galaxy or your location in your own planetary system, but dependent on the properties of the planet.

So that's an enlightened modern view of the concept of a zone.

So the zone is not a, it's a virtual zone in that sense, because it can take,

it can be in places that are not just in the narrow-minded swath

that's around the sun.

So that's good.

I hadn't thought about these other kinds of Goldilocks zones you're referencing.

So,

yeah, so, and for all we know, even the definitions we've come up with now, 20, 30 years from now, Carrie and Violetta, the eight-year-olds or the eight and 12-year-olds listening to this, in their day, they might look back at our definition, broadened definition of a Goldilocks zone and say, what do they know?

Because for all we know, they could be like life inside of volcanoes or something.

I mean, who knows?

Right, right.

And we haven't observed any rocky exoplanet atmospheres yet.

We're just beginning.

Right, right, right.

Okay.

Very good.

Very good.

So what I want to do now is go into a semi-lightning round.

And so, Sarah, pretend you're on the evening news and the whole interview is going to last just a couple of minutes.

And so

this is your soundbite.

quiz really can you can you give us a soundbite you've been very good in this program up to so far so i i think you'll come out out in flying colors.

So, Matt, let's see how many questions we can squeeze in.

We've only actually got a few questions left.

If that's uh,

okay, I think I know the answer to this one, but uh, Andrew Gundreau asks: My question is about the probability of life in the universe finding each other.

If we think of the universe as infinite and the axis of time as infinite, does it stand to reason the probability of life in different areas of the universe finding each other on both axes time and space approaches zero?

Oh, I like that.

My guess is no, but uh, I want to hear from the scientists.

Yeah, I didn't totally get that, the last part of that.

So he's saying if everything's infinite, life should find each other.

So why should it find each other?

I think the question is, if we're dealing with an infinite universe and a finite amount of life, would that not be so far apart from each other that it couldn't find each other?

No, he added another dimension.

Let's say life is there and we're here, and we go there and we find them.

Okay.

If space is infinite, that reduces the likelihood that they're just going to be there.

They're going to be probably much farther away from us.

That's the first axis on this.

The other axis is

maybe the life is there now, but they're not going to be there in 100 years.

So you have to intersect not only in time, but in place.

And if both the time axis and the place axis are infinite, what hope do we have of ever making contact?

I think I got his question.

I think you got it.

I think I got it.

That is the question.

Yes.

Yes, yes.

It really all depends on how common life is.

If life is rare, then yes, that question is an answer is valid.

But we all want to believe that

we see the ingredients for life everywhere.

And so we have every reason to hope that on each rocky planet, that's the right temperature, that there's a chance for life there, in which case, life is,

yeah.

Okay.

And but in terms of how far we've actually searched, my favorite reference there is

an analogy given by Jill Tarter of the SETI Institute.

And

this is so good.

I've given this a hundred times since then.

And we got her to say it on Star Talk.

So we have it bronzed in our

archives.

You can ask how much of the universe have we searched before we start saying there's no life here.

And if you look at all the parameter space, time, space, frequency of bandwidth, right?

You could be trying to say hi in one frequency and they're trying to say hi in in another frequency and there's ships passing in the night and you both conclude that there is no sign of intelligent life.

So she said, it's like going up to the ocean, scooping a cup, an empty cup, filling it with ocean water, looking at it and saying,

there are no whales in the ocean.

So in terms of how much total volume that of space time frequency is searchable.

And so that was depressing, but fascinating at the same time for me.

Right, right.

But at the same time, now I'm going to turn the tables and do the opposite of trashing all the comments.

Like, if you're scooping up that one glass of water, surely there is some kind of life in there.

So we're thinking that we can look at the nearest stars and the nearest planets.

And that the ingredients for life are everywhere and that they should come together often enough that we have a chance of finding signs of life.

Excellent.

Excellent.

So that's like taking a scoop of anywhere soil on Earth.

There's going to be life in it, no matter what.

Right.

Or any air, air parcel.

Even air.

Very cool.

Very cool.

Matt, let's slip in a couple more questions.

What do you think?

All right.

John David Newman says, is it possible that the galaxies we observe relatively easily are less likely to have life than the dwarf galaxies or wandering stars in deep space, which are more difficult to see?

Could wandering stars or dwarf galaxies in deep space be less threatening to life?

Well, at the moment, we're only able to observe the very nearest stars.

We can't see other galaxies.

So that question is

out of our purview at the moment.

However, each star is fairly isolated, and each star has its own planetary system as far as we can tell.

So it shouldn't matter which galaxy the planet is in in relation to whether life is there or not.

And we see the same kinds of stars in most galaxies.

There are differences, of course, but that repeats enough.

So I agree with you.

We will be perfectly happy searching stars in our own galaxy without having to go to others just to wonder if it's different.

But another point implicit there is there are some galaxies that have very rocking active nuclei with very deadly radiation coming out.

And it could be that some galaxies are hostile to the formation of complex molecules and more peaceful galaxies like the dwarf galaxies

that they may be more hospitable.

I mean, we don't really know this yet.

And I agree, Sarah, there's still much more.

searching to go before we start creating a galactic model for what life would or should be like.

Let's get one more question, man.

See if we can get it.

All right, well, I've got to combine these two then.

I'm really in a combining kick today.

These are both quite philosophical.

Jet Thomas asks, we as a species love to stimulate our senses by watching movies, listening to music, telling stories, and more.

Assuming an alien civilization is interested in leisure, could we hypothesize what a stimulation of different senses would look like outside of our familiar five and look for evidence of such things?

And then Chris Hampton says, what effect do you think the discovery of alien life would have on society?

Would borders eventually dissipate and self-identification move uh from Russian, American, etc., to earthling.

How long would the initial pandemonium last?

So, music, society, culture, and art, how would everything change in one sound?

Sarah, I think I was going to ask Neil for that because Neil is so articulate and good at speaking.

I think you should take a crack at it.

I'll take a quick crack at it.

It is interesting when you find something that's more other

than you are from each from among yourselves, it does act as a kind of binding force, And sometimes for the good, sometimes not.

But

I had hoped that we would have had this kind of binding force in the face of battling COVID.

COVID was like an alien, then it doesn't care what your skin color is or your gender or gender expression.

It doesn't care.

It'll infect you.

And that would be a good place to band together and fight it.

And we failed that test.

So I wish I had more confidence than I currently do in how we would react collectively as a species to

an alien, be they friendly or hostile.

And the other question was what?

It was about what kind of version of stories and art and music and

an alien civilization have and how would it differ from ours or interact with it?

Sarah, do you guys think much about the senses that an alien might have?

No.

I mean, is that something that you could look for, look for evidence of, or ways that they could have changed their environment to accommodate the different ways that they interact with each other?

No.

I mean, if you think about it for a moment, our oxygen on Earth, life on Earth, bacteria, cyanobacteria, you know, billions of years ago, they re-engineered our atmosphere.

They completely changed our atmosphere so it was unrecognizable.

So we can see giant things like that.

But small things like that animals do or that aliens would do, those are out of our a possibility for now yeah but you being like straight scientist there but now let me ask you sarah seger the human being who watches science fiction movies what

can you imagine well if if an alien had another sense what might it be

yeah that's a tough one i don't have a good answer for that

i can take any answer i don't have to be good well sometimes i i do like to think about our own planet earth and all the intelligent life here you know like the dolphins and octopus And there's a lot of creatures here that we think are highly intelligent.

And so I do like to think about how they interact with each other, what signs they give each other.

My favorite New Yorker comic, I've got to end,

was there were two dolphins swimming together, and they're looking up at two humans talking to each other, looking out of the water, and they see them.

And one dolphin says to the other, they face each other and make sounds, but it's not clear that they're actually communicating.

Dolphin with brains bigger than ours.

Sarah, it has been a delight to have you on.

And we neglected to even mention that you were co-author on the recent discovery of phosphine, a molecule in the upper atmosphere of Venus, a possible product of life.

I know that that result is still getting contested, but it's fun to watch science at its best.

when ideas come forth and people try to explain it in multiple ways.

So just good luck on that.

It was great to see you active in that.

And

your part memoir, The Smallest Lights in the Universe, it's a delight to see that contains a firsthand account, not only of your life, but the birth of an entire cottage industry in our beloved field of astrophysics, the search for exoplanets and the search for life itself.

So great to have you on and good luck with you.

Thank you.

Thanks for having me.

All right.

And Matt, always good to have you, man.

Oh, it's a pleasure.

Thanks for having me.

And we'll look for you on probably science.

Yes, please.

And I got it straight.

And one.

And also your book as well, Neil.

We've got to give that another plug.

Oh, so

another plug for Cosmic Queries.

If you like this format,

and if you're listening, you probably do, because it's one of our most popular.

We just put it all in one book.

It's got the deepest questions.

What is life?

And what is the universe made of?

And how did it begin?

How will it end?

And are there multiverses?

And so we're very proud of that book as a Star Talk community because

a lot of it has been inspired by shows like this where you write in and ask your deepest questions.

And that inspired us to put the book out there.

And it's a product of the Star Talk family.

This has been Star Talk Cosmic Queries.

I'm Neil deGrasse Tyson, your personal astrophysicist.

As always, keep looking up.

This is Marshawn Lynch.

You and I make decisions every day, but on prize picks, being right can get you paid.

So I'm here to make sure you don't miss any of the action this football season with prize picks it's good to be right download the prize picks app today and use code pandora to get 50 in lineups after you play your first five dollar lineup that's code pandora to get fifty dollars in lineups after you play your first five dollar lineup prize picks it's good to be right must be present in certain states visit prize picks.com for restrictions and details

Did you know that the United States produces 13 million barrels of crude oil every day?

Enough to fill 800 Olympic swimming pools.

Oil and natural gas are refined into gasoline, diesel, and jet fuel and used to make unexpected everyday essentials like shoes, cell phones, even life-saving medicines.

People rely on oil and gas and on energy transfer to safely deliver it through an underground system of pipelines across the country.

Learn more at energytransfer.com.