3 moons and a planet that could have alien life | James Green

Translator: Lúa Cruz Fernández Reviewer: Elena Pérez Gómez

Is there life beyond Earth in our solar system?

Existe vida máis alá da Terra no noso sistema solar?

Wow, what a powerful question.

Vaia, que pregunta máis poderosa.

You know, as a scientist --

Saben, coma científicos,

planetary scientist --

científicos planetario,

we really didn't take that very seriously until recently.

non nos tomamos isto moi en serio, até fai pouco.

Carl Sagan always said,

Carl Sagan sempre dicía:

"It takes extraordinary evidence for extraordinary claims."

"Alegacións extraodinarios esixen probas extraordinarias".

And the claims of having life beyond Earth

E as probas de que existe vida máis alá da Terra

need to be definitive,

teñen que ser definitivas,

they need to be loud

teñen que ser claras

and they need to be everywhere for us to be able to believe it.

e teñen que estar en todas partes para que o poidamos crer.

So how do we make this journey?

Entón, como facemos isto?

What we decided to do

Primeiro, o que deicimos facer

is first look for those ingredients for life.

é procurar os ingredientes da vida.

The ingredients of life are:

Os ingredientes da vida son:

liquid water --

auga en estado líquido,

we have to have a solvent,

temos que ter un solvente,

can't be ice, has to be liquid.

non pode ser xeo, ten que ser líquido.

We also have to have energy.

Tamén precisamos enerxía.

We also have to have organic material --

Amais, necesitamos material orgánico,

things that make us up,

cousas que nos compón,

but also things that we need to consume.

mais tamén cousas que precisamos consumir.

So we have to have these elements

Entón, necesitamos ter estes elementos

in environments for long periods of time

en ambientes e durante longos periodos de tempo

for us to be able to be confident that life,

para estar seguros de que a vida,

in that moment when it starts,

no momento no que comeza,

can spark and then grow and evolve.

pode xurdir e entón crecer e evolucionar.

Well, I have to tell you that early in my career,

Ben, teño que lles dicir que nos comezos da miña carreira,

when we looked at those three elements,

cando procurabamos estes 3 elementos,

I didn't believe that they were beyond Earth

non cría que estivesen máis alá da Terra

in any length of time and for any real quantity.

en calquera tempo nin en calquera cantidade.

Why? We look at the inner planets.

Por que? Mirabamos para os planetas interiores.

Venus is way too hot -- it's got no water.

Venus é moi quente, non ten auga.

Mars -- dry and arid.

Marte: seco e árido.

It's got no water.

Non ten auga.

And beyond Mars,

E máis alá de Marte,

the water in the solar system is all frozen.

a auga no sistema solar está xeada.

But recent observations have changed all that.

Mais observacións recentes mudaron todo isto.

It's now turning our attention to the right places

Agora a nosa atención está posta nos lugares correctos

for us to take a deeper look

para que miremos máis a fondo

and really start to answer our life question.

e poidamos comezar a responder as nosas preguntas sobre a vida.

So when we look out into the solar system,

Así, cando observarmos o noso sistema solar,

where are the possibilities?

cales son as posibilidades?

We're concentrating our attention on four locations.

Centramos a nosa atención en catro lugares.

The planet Mars

O planeta Marte

and then three moons of the outer planets:

e tres lúas de planetas externos;

Titan, Europa and small Enceladus.

Titán, Europa e a pequena Encélado.

So what about Mars?

E que ten Marte?

Let's go through the evidence.

Vexamos as evidencias.

Well, Mars we thought was initially moon-like:

Pensamos que Marte era coma a Lúa inicialmente:

full of craters, arid and a dead world.

cheo de cráteres, árido e un mundo sen vida.

And so about 15 years ago,

Entón, hai uns 15 anos,

we started a series of missions to go to Mars

comezamos unha serie de misións a Marte

and see if water existed on Mars in its past

para verificar se existiu auga en Marte

that changed its geology.

que mudou a súa xeoloxía.

We ought to be able to notice that.

Deberiamos poder advertir isto.

And indeed we started to be surprised right away.

E de feito comezamos a sorprendernos de novo.

Our higher resolution images show deltas and river valleys and gulleys

As imaxes de alta resolución amosaban deltas e vales de ríos e cañóns

that were there in the past.

que estiveron aí no pasado.

And in fact,

E de feito,

Curiosity --

Curiosity,

which has been roving on the surface now for about three years --

que se está a mover pola superficie dende hai uns tres anos,

has really shown us that it's sitting in an ancient river bed,

amosounos que está no antigo leito dun río,

where water flowed rapidly.

onde a auga discorría rapidamente.

And not for a little while,

E non durante pouco tempo,

perhaps hundreds of millions of years.

talvez durante centos de milleiros de anos.

And if everything was there,

E se existiu algo aí,

including organics,

incluíndo material orgánico,

perhaps life had started.

talvez comezara a vida.

Curiosity has also drilled in that red soil

Curiosity tamén furou o chan vermello

and brought up other material.

e ensinou outros materiais.

And we were really excited when we saw that.

Emocionámonos moito cando vimos isto.

Because it wasn't red Mars,

Porque non era vermello Marte,

it was gray material,

era material gris,

it's gray Mars.

era gris Marte.

We brought it into the rover,

Trouxemos isto,

we tasted it,

testámolo,

and guess what?

e adiviñade que?

We tasted organics --

Estabamos a testar material orgánico:

carbon, hydrogen, oxygen,

carbono, hidróxeno, osíxeno,

nitrogen, phosphorus, sulfur --

nitróxeno, fósforo, xofre,

they were all there.

estaban aí.

So Mars in its past,

Entón, Marte, no pasado,

with a lot of water,

con moita auga,

perhaps plenty of time,

talvez con moito tempo,

could have had life,

puido ter vida,

could have had that spark,

puido ter esa chispa,

could have grown.

puido crecer.

And is that life still there?

E aínda está esa vida aí?

We don't know that.

Non o sabemos.

But a few years ago

Mais hai uns anos

we started to look at a number of craters.

comezamos a mirar a unha serie de cráteres.

During the summer,

Durante o verán,

dark lines would appear down the sides of these craters.

aparecían unhas liñas negras baixo estes cráteres.

The more we looked,

Canto máis mirabamos,

the more craters we saw,

máis cráteres viamos,

the more of these features.

e máis as tiñan.

We now know more than a dozen of them.

Agora coñecemos máis dunha ducia deles.

A few months ago the fairy tale came true.

Hai uns meses o conto de fadas convertiuse en realidade.

We announced to the world that we know what these streaks are.

Anunciamos ao mundo que descubrimos que eran esas liñas.

It's liquid water.

É auga, líquida.

These craters are weeping during the summer.

Eses cráteres pingan durante o verán.

Liquid water is flowing down these craters.

Auga líquida flúe nesos cráteres.

So what are we going to do now --

Entón, que imos facer agora,

now that we see the water?

agora que vemos a auga?

Well, it tells us that Mars has all the ingredients necessary for life.

Ben, dinos que Marte ten todos os ingredientes para a vida.

In its past it had perhaps two-thirds of its northern hemisphere --

No pasado probablemente dous terzos do hemisferio norte,

there was an ocean.

eran océano.

It has weeping water right now.

Ten auga goteando agora mesmo.

Liquid water on its surface.

Auga líquida na súa superficie.

It has organics.

Ten materia orgánica.

It has all the right conditions.

Ten todas as condicións necesarias.

So what are we going to do next?

Entón, que imos facer agora?

We're going to launch a series of missions

Imos lanzar unha serie de misións

to begin that search for life on Mars.

para comezar a buscar vida en Marte.

And now it's more appealing than ever before.

E agora é máis atractivo que nunca.

As we move out into the solar system,

Cando avanzamos no noso sistema solar,

here's the tiny moon Enceladus.

aquí está a pequena lúa, Encélado.

This is not in what we call the traditional habitable zone,

Non é o que chamaría unha zona habitable tradicional,

this area around the sun.

esta área redor do sol.

This is much further out.

Iso está moito máis afastado.

This object should be ice over a silicate core.

Este obxecto debería ser xeo sobre un núcleo de silicato.

But what did we find?

Mais que atopamos?

Cassini was there since 2006,

Cassini estivo aí dende 2006,

and after a couple years looked back after it flew by Enceladus

e despois duns anos mirou cara atrás despois de voar de Encélado

and surprised us all.

e sorprendeunos a todos.

Enceladus is blasting sheets of water out into the solar system

Encélado está a tirar láminas de auga ao noso sistema solar

and sloshing back down onto the moon.

e rebotando de novo cara a lúa.

What a fabulous environment.

Que ambiente tan fabuloso.

Cassini just a few months ago also flew through the plume,

Hai uns meses, Cassini tamén voou sobre sobre unha columna,

and it measured silicate particles.

e mediu as partículas de silicato.

Where does the silica come from?

De onde provén o sílice?

It must come from the ocean floor.

Debe provir do chan do océano.

The tidal energy is generated by Saturn,

Saturno xera a enerxía mareomotriz,

pulling and squeezing this moon --

empurrando e presionando esta lúa

is melting that ice,

está derretendo o xeo,

creating an ocean.

creando océanos.

But it's also doing that to the core.

Mais tamén está a facer iso co núcleo.

Now, the only thing that we can think of

Agora, o único que podemos imaxinar

that does that here on Earth as an analogy ...

que ten unha analoxía aquí na Terra...

are hydrothermal vents.

Son os respiradeiros hidrotérmicos.

Hydrothermal vents deep in our ocean were discovered in 1977.

Os respiradeiros hidrotérmicos descubríronse en 1977 no noso océano.

Oceanographers were completely surprised.

Os osceanógrafos estaban moi sorprendidos.

And now there are thousands of these below the ocean.

E agora hai miles destes baixo o océano.

What do we find?

Que atopamos?

The oceanographers, when they go and look at these hydrothermal vents,

Os oceanógrafos, cando observan estes respiradeiros hidrotérmicos,

they're teeming with life,

están cheos de vida,

regardless of whether the water is acidic or alkaline --

e non importa se a auga é aceda ou alcalina,

doesn't matter.

non importa.

So hydrothermal vents are a fabulous abode for life here on Earth.

Entón, os respiradeiros hidrotérmicos son unha fabulosa morada para a vida na Terra.

So what about Enceladus?

Entón, que pasa con Encélado?

Well, we believe because it has water

Ben, cremos que como ten auga

and has had it for a significant period of time,

e tívoa durante moito tempo,

and we believe it has hydrothermal vents

e cremos que ten respiradeiros hidrotérmicos

with perhaps the right organic material,

e quizais o material orgánico axeitado,

it is a place where life could exist.

pode ser un lugar onde existiu a vida.

And not just microbial --

E non só microbiana,

maybe more complex because it's had time to evolve.

talvez máis complexa porque tivo tempo de evolucionar.

Another moon, very similar,

Outra lúa, moi parecida,

is Europa.

é Europa.

Galileo visited Jupiter's system in 1996

Galileo visitou o sistema de Xúpiter en 1996

and made fabulous observations of Europa.

e fixo observacións fabulosas de Europa.

Europa, we also know, has an under-the-ice crust ocean.

Tamén sabemos que Europa ten un oceáno de cortiza baixo o xeo.

Galileo mission told us that, but we never saw any plumes.

A misión Galileo amosounos isto, máis nunca vimos ningunha columna.

But we didn't look for them.

Máis tampouco as buscabamos.

Hubble,

Hubble,

just a couple years ago,

hai só uns anos,

observing Europa,

cando observaba Europa,

saw plumes of water

viu columnas de auga

spraying from the cracks in the southern hemisphere,

que saían das fendas no hemisferio sur,

just exactly like Enceladus.

exactamente coma Encélado.

These moons,

Estas lúas,

which are not in what we call a traditional habitable zone,

que non están no que normalmente chamamos unha zona habitable,

that are out in the solar system,

que están fóra no sistema solar,

have liquid water.

teñen auga líquida.

And if there are organics there,

E si hai material orgánico aí,

there may be life.

pode haber vida.

This is a fabulous set of discoveries

É unha serie de descubrimentos fabulosos

because these moons have been in this environment like that

porque estas lúas estiveron neste ambiente así

for billions of years.

durante miles de millóns de anos.

Life started here on Earth, we believe, after about the first 500 million,

A vida comezou na Terra, cremos, despois dos primeiros 500 millóns,

and look where we are.

e mira onde estamos.

These moons are fabulous moons.

Estas lúas son fabulosas.

Another moon that we're looking at is Titan.

Outra lúa á que observamos é Titán.

Titan is a huge moon of Saturn.

Titán é unha lúa xigante de Saturno.

It perhaps is much larger than the planet Mercury.

É, quizais, moito máis grande que o planeta Mercurio.

It has an extensive atmosphere.

Ten unha atmosfera enorme.

It's so extensive --

É moi grande,

and it's mostly nitrogen with a little methane and ethane --

e é na súa maioría nitróxeno cun chisco de metano e etano,

that you have to peer through it with radar.

que se precisa dun radar para observala.

And on the surface, Cassini has found liquid.

E na superficie, Cassini atopou líquido.

We see lakes ...

Vemos lagos...

actually almost the size of our Black Sea in some places.

Case do tamaño do mar negro nalgúns lugares.

And this area is not liquid water;

E esta área non é auga líquida;

it's methane.

é metano.

If there's any place in the solar system where life is not like us,

Se hai algún lugar no sistema solar onde a vida non é coma nós,

where the substitute of water is another solvent --

onde o sustituto da auga é outro solvente,

and it could be methane --

e poida ser o metano,

it could be Titan.

podería ser Titán.

Well, is there life beyond Earth in the solar system?

Ben, hai vida máis alá da Terra no noso sistema solar?

We don't know yet,

Aínda non o sabemos,

but we're hot on the pursuit.

máis sempre estamos na busca.

The data that we're receiving is really exciting

Os datos que recibimos nos entusiasman

and telling us --

e nos din,

forcing us to think about this in new and exciting ways.

fannos pensar nesto en novos xeitos.

I believe we're on the right track.

Creo que estamos no camiño correcto.

That in the next 10 years, we will answer that question.

Que en 10 anos responderemos esa pregunta.

And if we answer it,

E se a respondemos,

and it's positive,

e é un si,

then life is everywhere in the solar system.

significará que a vida está en todo o sistema solar.

Just think about that.

Pensen nisto.

We may not be alone.

Talvez non estamos sós.

Thank you.

Grazas.

(Applause)

(Aplausos)