Hi, I'm Jill Tarter,

and today we're gonna do some ET support.

We'll talk about life beyond earth.

[upbeat music]

First question comes from @JohnMaksuta.

If you found intelligent life on another planet,

would you tell the public the truth or keep it a secret?

Absolutely no way we would keep this a secret, John.

We are going to tell the world.

It's just not possible to keep this kind of thing a secret

and we don't intend to.

@CoraxSays, Extraterrestrial etiquette,

how should humanity interact with alien intelligence?

I have to say that although we're really proud

of ourselves and we think that we are the pinnacle

of evolution, the top dog on this planet,

if someone else can get from their star to our planet,

they are in fact a lot more technologically advanced.

I would say the etiquette is we're gonna play

by their rules.

@AntonioParis says,

Why do we assume ET uses radio to communicate?

Is SETI a waste of time and millions of dollars?

What do you think?

Well, me, I think, obviously not.

That's what I've spent my career doing,

trying to answer this really, really old human question

of are we alone in the cosmos?

Why do we use radio?

Well, we use radio and optical wavelengths.

Particularly, radio travels across the very vast distances

between the stars and our galaxy without being scattered

or absorbed by the dust.

So @lisepease, The Fermi paradox,

mathematically the universe should be teeming

with intelligent life.

So why don't we see extraterrestrial versions

in all directions?

Really interesting question,

the answer is we've hardly begun to look.

Let me give you an example.

If that volume of space we need to explore is equal

to the volume of all the world's oceans, in 50 plus years,

we've observed only about one hot tub's worth of the ocean.

Maybe it's not so surprising

that we haven't detected anything yet.

We need to think in terms of cosmic times

and not human lifetimes before we decide we're alone

because we haven't found anything.

@EllieMaloneyFic wants to know,

Should NATO and the U.S. military develop

planetary defense systems in case

of an extraterrestrial threat?

Oh, come on, get real.

I think what we should develop a defense system

against asteroids, near-earth objects,

rocks that have our name on it.

And that in fact could be big enough

that a collision with earth could be civilization ending.

Think about the dinosaurs, they didn't have a space program.

If they had, maybe they wouldn't be extinct.

@jodyscottinfo, Is math a universal language

to make contact with another intelligence,

or this is just anthropocentrism?

Probably, if you're going to be building

any kind of transmitter, or receiver, you need math.

So in that sense, it's universal.

But now we're thinking the way that we express math

may be shaped by the very configuration

of our own human brains.

Math may be universal, the function may be universal,

but it may be that we will have a difficult time

understanding someone else's expression of that math.

Don't know, would love to have that problem.

@Rachel84799974, At what year do you think

we will discover aliens, if ever?

Rachel, I can't answer that question.

All I can say is that if we don't search, we won't succeed.

It's an open question and one that I think

perhaps the 21st century will give an answer to.

@VinylOnTour, Aliens will land on earth,

you have only five songs to explain

what music means to mankind, what songs would you choose?

Oh, wow.

I think the songs of my youth

are probably totally alien to you.

Rather than songs, I might go with Bach

because I think that is just the most beautiful music

we've ever created.

Johnny B Goode,

that was on the Voyager Golden Record as well as Bach.

Music is a personal taste.

I'd send Bach and I'd brag.

@acarboni, We assume aliens look different than us.

What if their intelligence is unrecognizable?

How do you give them an IQ test?

Think about how are we gonna interact with them.

Are we detecting deliberate messages

in optical or radio wavelengths that they've sent us?

Are they here looking us in the face?

That's going to determine how we interact with them.

If they can get here, they're a lot smarter than we are.

You can forget the test, we'll just follow their rules.

@SkipsAbs, Even if their is other intelligent life

in the universe,

is our civilization even worth contacting?

Yeah, I suspect we are.

We're doing a lot of things are maybe not the wisest,

but we are us.

We are different than they are.

I think the most interesting thing in the universe

might be how diverse the laws

of physics and chemistry can make life.

How many different ways can evolution end up producing

creatures that are intelligent, technological,

even microbial?

How many different ways can you make life?

That might be the biggest question of the cosmos

and one that they'd be interested in finding out

what happened here.

@bobbybeaulieu wants to know,

Did U.S. fighter pilots see a UFO?

I don't know, I've seen those videos too.

I don't know what they are.

I don't know whether the equipment,

which was in fact quite new,

was behaving properly.

All I can is that there's no evidence

that indicates that that's a spacecraft

from another intelligent species.

More than likely,

we have some problems with our own equipment.

It's going to take more than that

to prove that aliens are here.

@willmckim, How much do we think all this recent UFO news

is prepping the public for a discussion of actual content?

I think that, like many things,

our interest in this question is cyclical.

We get really hyped up about it,

somebody makes a claim, people discuss it,

and then after a while the Kardashians do something else

and we lose interest.

What if we are the aliens that we seek

and earth was once populated

by a much more intelligent life force

until we destroyed it?

Well, think about that.

The planet is really quite active.

About the oldest rocks we can find

are a little bit more than four billion years old

and the planet we think formed

about four and a half billion years ago.

Now, these rocks produce stones called zircons

and the zircons sometimes have inclusions

that have biological ratioses of light carbon to heavy carbon.

So we're thinking, maybe life went back that far.

But we don't find any huge trash heaps,

we don't find any evidence of foundries,

or large structures, or roads.

Let's just say we don't see any evidence for that.

Intelligence is proportional to the number of thoughts

we can simultaneously recall and hold in our minds

as we explore new ideas.

So what would we look like to an alien species

who could juggle 10 or 20 times as many thoughts

as our smartest human?

We wouldn't look very intelligent, would we?

We have to ask questions, not in our language,

but in their language.

We have to try and interact with nonhuman intelligence

in ways that they perceive.

And we're beginning to do a little bit of that

with whales, and with dolphins,

and with a number of other species.

We can actually understand

that prairie dogs standing up in the field

are saying to one another,

Hey, there's a big guy over there

in the yellow sweater, he's back.

Other intelligence is going to have to speak to us

in our language if we're going to have any ability

to communicate.

@gdbassett, Thought experiment,

if our AI could lead to an existential threat

and there may be other intelligent life in the universe,

what about their AI?

Yeah, good question.

I think it's quite likely that what we will encounter

is their artificial intelligence.

It can be propagated in so many different ways

between the stars.

As we build artificial intelligence

and hopefully, as they built their artificial intelligence,

there are going to be constraints

that build into the structure.

Goals that remain consistent

with goals that we have for ourselves.

If it's rogue, game over.

What is the organizing principal behind intelligent life?

Whoa, what a question.

We can't define intelligence.

What we have done to make progress in this field

is to use technology as our proxy for intelligence.

So if we detect evidence of someone else's

technology out there,

we will assume that at some time

there was an intelligent entity that created the technology.

Best we can do.

@zee_shah, If there's a new planet,

who will own the real estate?

Will NASA get into the property development business?

Great question.

We have confirmed over 4,000 other planets

around other stars.

The question of who owns them,

who can mine them, is a work in progress.

The U.N. treaty of outer space says

that it is possible to benefit

from an extraterrestrial body without owning it.

That no one owns it.

Basing this meta-law, if you wish, on the law of the seas.

No one owns the ocean,

but people can in fact salvage and fish,

and benefit from the oceans.

That's kind of the playing field that we're dealing now

with extrasolar bodies.

It's a work in progress.

We'll see how it plays out.

@CodeIsBroken, oh yeah, my code usually is.

If aliens exist who could be far, far older than humanity

and have used similar comms tech to us,

how come we've not heard a thing?

Because the cosmos is pretty damn big.

We're talking about signals here for communication.

Maybe we need to look for something else,

maybe we're doing an absolutely exquisite job

at looking for just the wrong thing.

Maybe we haven't figured out

that the thing that intelligent,

advanced societies use to communicate is Zeta rays.

And we haven't discovered them yet.

@K8smommyLisa, What if they are trying to communicate

but we just don't realize it yet?

Yes, absolutely.

What if they're using some technology, some physics,

that we haven't yet invented?

We could be missing a signal.

The only strategy is to stay around long enough

so that we can get smart enough

that we invent the technology

and then we can find the signal.

@CaptainFishMugs, Do aliens have belly buttons?

Yes, well, that's a good question.

I'd love to know the answer to that.

We look at various form of life on this planet,

not all of them have belly buttons,

so it's possible that aliens don't either.

@ET_Exists, oh, I like that.

When will we hear from ET?

And there are lots of hashtags here.

I don't know the answer to that question.

I don't know if ET is out there.

I think it's likely.

The universe appears to be relatively bio-friendly.

We know about lots of planets around other stars.

We now know about lots of lifeforms on this planet

that exist in extreme, extreme for us, environments.

There's a chance.

The only way that we'll know is to look.

And when?

Can't answer that question.

Talk to my great-granddaughter,

she may have an answer for you.

That was ET support.

That's what I know, and mostly what I don't know.

But I'm looking forward to learning more with all of you.