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

Translator: Agustí Gállego Reviewer: Elena Pérez Gómez

Is there life beyond Earth in our solar system?

Hi ha vida més enllà de la Terra, al nostre sistema solar?

Wow, what a powerful question.

Caram, quina pregunta més poderosa.

You know, as a scientist --

Com a científics,

planetary scientist --

com a planetòlegs,

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

no ens ho havíem plantejat seriosament fins fa ben poc.

Carl Sagan always said,

Carl Sagan sempre deia:

"It takes extraordinary evidence for extraordinary claims."

"Les afirmacions extraordinàries necessiten proves extraordinàries".

And the claims of having life beyond Earth

Per afirmar que hi ha vida extraterrestre

need to be definitive,

calen proves definitives,

they need to be loud

que siguin convincents

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

i han d'estar per tot arreu perquè ens les creguem.

So how do we make this journey?

Com comencem aquest viatge?

El que vam decidir

What we decided to do

is first look for those ingredients for life.

és buscar, primer, els ingredients necessaris per a la vida.

The ingredients of life are:

Aquests ingredients són:

liquid water --

aigua líquida,

we have to have a solvent,

hem de tenir un dissolvent,

can't be ice, has to be liquid.

no pot ser gel, ha de ser líquid.

We also have to have energy.

També hi ha d'haver energia.

We also have to have organic material --

I matèria orgànica,

things that make us up,

allò de què estem fets.

però també el que hem de consumir.

but also things that we need to consume.

So we have to have these elements

Per tant, hem de tenir aquests elements

in environments for long periods of time

en entorns durant molt de temps

for us to be able to be confident that life,

per poder estar segurs que la vida,

in that moment when it starts,

quan comenci,

pot sorgir, créixer i evolucionar.

can spark and then grow and evolve.

Us he de dir que al principi,

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

when we looked at those three elements,

quan observàvem aquests tres elements,

I didn't believe that they were beyond Earth

no pensava que existissin fora de la Terra

durant el temps suficient o en quantitats significatives.

in any length of time and for any real quantity.

Why? We look at the inner planets.

Per què? Fixem-nos en els planetes interiors.

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

Venus és massa calent, no hi ha aigua.

Mars -- dry and arid.

Mart: sec i àrid.

It's got no water.

Tampoc té aigua.

I més enllà de Mart,

And beyond Mars,

the water in the solar system is all frozen.

tota l'aigua del sistema està congelada.

Però observacions recents ho han canviat tot.

But recent observations have changed all that.

It's now turning our attention to the right places

Ara ens centrem en els llocs adequats

for us to take a deeper look

ho observem amb més atenció

and really start to answer our life question.

i podem començar a respondre la pregunta de si hi ha vida.

Així que, si mirem el sistema solar,

So when we look out into the solar system,

on n'hi podria haver?

where are the possibilities?

We're concentrating our attention on four locations.

Ens centrem en quatre llocs.

The planet Mars

El planeta Mart

and then three moons of the outer planets:

i tres llunes dels planetes exteriors:

Titan, Europa and small Enceladus.

Tità, Europa i la petita Encèlad.

So what about Mars?

Sobre Mart, què?

Let's go through the evidence.

Repassem l'evidència.

Well, Mars we thought was initially moon-like:

Primer, crèiem que Mart era similar a la Lluna.

full of craters, arid and a dead world.

ple de cràters, àrid i desolat.

And so about 15 years ago,

I fa uns 15 anys,

vam començar missions per anar a Mart

we started a series of missions to go to Mars

and see if water existed on Mars in its past

i comprovar si havia tingut aigua

that changed its geology.

que canviés la seva geologia.

We ought to be able to notice that.

Havíem de ser capaços de notar-ho.

I vam quedar sorpresos només començar.

And indeed we started to be surprised right away.

Our higher resolution images show deltas and river valleys and gulleys

Les imatges mostraven deltes, valls fluvials i fondalades

that were there in the past.

que van existir en el passat.

And in fact,

I, de fet,

Curiosity --

Curiosity

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

que ja fa uns tres anys que recorre el planeta

ens ha mostrat que és en un antic llit d'un riu,

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

where water flowed rapidly.

en què l'aigua hi fluïa ràpidament.

And not for a little while,

I no durant poc temps,

perhaps hundreds of millions of years.

potser durant centenars de milions d'anys.

I si tot hi era,

And if everything was there,

including organics,

també matèria orgànica,

perhaps life had started.

potser hi va sorgir vida.

Curiosity has also drilled in that red soil

Curiosity també ha perforat el terra

and brought up other material.

i ha extret altres materials.

And we were really excited when we saw that.

Ens vam emocionar, quan ho vam veure.

Because it wasn't red Mars,

Perquè no era vermell,

it was gray material,

era de color gris,

it's gray Mars.

el planeta gris.

We brought it into the rover,

Ho vam portar al vehicle,

we tasted it,

vam treure'n mostres

and guess what?

i sabeu què?

We tasted organics --

Vam trobar-hi matèria orgànica.

carbon, hydrogen, oxygen,

Carboni, hidrogen, oxigen,

nitrogen, phosphorus, sulfur --

nitrogen, fòsfor, sofre...

they were all there.

hi havia tot això.

So Mars in its past,

Mart, en el passat,

with a lot of water,

amb molta aigua,

potser molt de temps,

perhaps plenty of time,

podria haver tingut vida,

could have had life,

could have had that spark,

podria haver-hi sorgit,

could have grown.

i haver crescut.

And is that life still there?

I aquella vida encara hi és?

We don't know that.

No ho sabem.

But a few years ago

Però fa uns anys

vam començar a mirar alguns cràters.

we started to look at a number of craters.

During the summer,

A l'estiu,

dark lines would appear down the sides of these craters.

apareixien línies fosques, baixant pels costats.

The more we looked,

Com més buscàvem,

com més cràters miràvem,

the more craters we saw,

the more of these features.

més línies trobàvem.

We now know more than a dozen of them.

N'hem trobat més d'una dotzena.

A few months ago the fairy tale came true.

Fa uns mesos, l'impossible es va convertir en realitat.

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

Vam fer públic que ja sabíem què eren aquestes línies.

It's liquid water.

És aigua líquida.

Els cràters ploren a l'estiu.

These craters are weeping during the summer.

Liquid water is flowing down these craters.

Baixa aigua líquida pels cràters.

So what are we going to do now --

Què farem ara,

now that we see the water?

ara que veiem l'aigua?

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

Bé, ens diu que Mart té els ingredients per tenir vida.

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

En el passat, pot ser que, en dos terços de l'hemisferi nord

there was an ocean.

hi hagués un oceà.

It has weeping water right now.

Té aigua líquida ara mateix.

Liquid water on its surface.

Aigua líquida a la superfície.

It has organics.

Té matèria orgànica.

It has all the right conditions.

Té les condicions correctes.

Què farem ara, doncs?

So what are we going to do next?

Iniciarem un seguit de missions

We're going to launch a series of missions

to begin that search for life on Mars.

per buscar vida a Mart.

And now it's more appealing than ever before.

I ara la cerca és més atractiva que mai.

As we move out into the solar system,

Si ens endinsem en el sistema solar,

here's the tiny moon Enceladus.

hi trobem la petita lluna Encèlad.

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

No és la zona habitable tradicional,

this area around the sun.

aquesta àrea al voltant del sol.

This is much further out.

Està molt més allunyada.

This object should be ice over a silicate core.

Això hauria de ser de gel sobre un nucli de silicat.

But what did we find?

Però què vam descobrir?

Cassini was there since 2006,

Cassini era allà des del 2006,

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

i després d'uns anys, va passar per Encèlad

and surprised us all.

i ens va sorprendre a tots.

Enceladus is blasting sheets of water out into the solar system

Encèlad envia capes d'aigua cap al sistema solar

and sloshing back down onto the moon.

que cauen un altre cop sobre la lluna.

What a fabulous environment.

Quin entorn més fabulós.

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

Cassini fa uns mesos, va travessar la columna

and it measured silicate particles.

i va detectar partícules de silicat.

Where does the silica come from?

D'on ve el silici?

It must come from the ocean floor.

Ha de venir del fons de l'oceà.

The tidal energy is generated by Saturn,

Saturn crea l'energia de la marea,

pulling and squeezing this moon --

atraient i estrenyent la lluna

està desfent el gel,

is melting that ice,

creating an ocean.

i creant un oceà.

But it's also doing that to the core.

Però també ho fa al nucli.

Now, the only thing that we can think of

Per ara, l'única cosa que sabem

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

que fa això a la Terra, com a analogia

són les fumaroles hidrotermals.

are hydrothermal vents.

Les fumaroles es van descobrir al fons de l'oceà al 1977.

Hydrothermal vents deep in our ocean were discovered in 1977.

Els oceanògrafs es van sorprendre molt.

Oceanographers were completely surprised.

And now there are thousands of these below the ocean.

I ara n'hi ha milers sota l'oceà.

What do we find?

Què hi descobrim?

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

Les fumaroles hidrotermals, quan els oceanògrafs les observen,

they're teeming with life,

desborden vida,

encara que l'aigua sigui àcida o alcalina,

regardless of whether the water is acidic or alkaline --

doesn't matter.

tant és.

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

Les fumaroles són excel·lents per a la vida a la Terra.

So what about Enceladus?

I a Encèlad?

Pensem que com que té aigua

Well, we believe because it has water

l'ha tingut durant molt de temps,

and has had it for a significant period of time,

and we believe it has hydrothermal vents

i pensem que té fumaroles,

with perhaps the right organic material,

potser amb la matèria orgànica adequada,

it is a place where life could exist.

és un lloc on hi pot haver vida.

And not just microbial --

No només microbiana

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

sinó també més complexa, perquè hi ha hagut temps per evolucionar.

Another moon, very similar,

Una altra lluna, molt similar,

is Europa.

és Europa.

Galileo visited Jupiter's system in 1996

Galileo va visitar Júpiter al 1996

i va aportar dades sobre Europa.

and made fabulous observations of Europa.

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

Sabem que Europa té un oceà sota la capa de gel.

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

La missió Galileo ho va mostrar, però no hem vist que expulsés res.

But we didn't look for them.

Però tampoc no ho vam buscar.

Hubble,

El Hubble,

just a couple years ago,

fa un parell d'anys,

observing Europa,

mentre observava Europa,

saw plumes of water

va veure columnes d'aigua

spraying from the cracks in the southern hemisphere,

que sorgien de l'hemisferi sud,

just exactly like Enceladus.

igual que a Encèlad.

These moons,

Aquests satèl·lits,

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

que no són a la zona habitable habitual,

that are out in the solar system,

que són a la zona exterior del sistema,

have liquid water.

tenen aigua líquida.

I si hi ha matèria orgànica,

And if there are organics there,

potser hi ha vida.

there may be life.

Són uns descobriments extraordinaris

This is a fabulous set of discoveries

because these moons have been in this environment like that

perquè aquests satèl·lits han estat en aquestes condicions

durant milers de milions d'anys.

for billions of years.

La vida a la Terra va començar després dels primers 500 milions,

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

and look where we are.

i mireu on som ara.

These moons are fabulous moons.

Aquestes llunes són meravelloses.

Another moon that we're looking at is Titan.

També observem un altre satèl·lit: Tità.

Titan is a huge moon of Saturn.

Tità és una lluna enorme de Saturn.

It perhaps is much larger than the planet Mercury.

Probablement és més gran que Mercuri.

It has an extensive atmosphere.

Té una atmosfera extensa.

És tan extensa...

It's so extensive --

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

i és sobretot nitrogen, amb una mica de metà i età

that you have to peer through it with radar.

que hi has de mirar a través amb radar.

And on the surface, Cassini has found liquid.

A la superfície, Cassini hi ha trobat líquid.

We see lakes ...

Hi veiem llacs

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

de fet, en alguns llocs, gairebé de la mida del Mar Negre.

And this area is not liquid water;

Aquests llacs no són d'aigua líquida,

it's methane.

són de metà.

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

Si hi ha algun lloc al sistema solar, on la vida no és com la coneixem,

where the substitute of water is another solvent --

on el substitut de l'aigua és un altre dissolvent,

and it could be methane --

potser el metà,

podria ser Tità.

it could be Titan.

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

Hi ha vida extraterrestre en el sistema solar?

We don't know yet,

No ho sabem, encara,

but we're hot on the pursuit.

però ens hi estem apropant.

The data that we're receiving is really exciting

Les dades que rebem són fascinants,

and telling us --

i ens diuen,

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

ens obliguen a pensar de manera completament diferent.

I believe we're on the right track.

Penso que anem pel bon camí.

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

Que en 10 anys respondrem la pregunta.

I si ho aconseguim,

And if we answer it,

i la resposta és afirmativa,

and it's positive,

aleshores hi ha vida per tot el sistema solar.

then life is everywhere in the solar system.

Just think about that.

Penseu-hi.

We may not be alone.

Potser no estem sols.

Thank you.

Gràcies.

(Applause)

(Aplaudiments)