Well, you know, sometimes the most important things come in the smallest packages. I am going to try to convince you, in the 15 minutes I have, that microbes have a lot to say about questions such as, "Are we alone?" and they can tell us more about not only life in our solar system but also maybe beyond, and this is why I am tracking them down in the most impossible places on Earth, in extreme environments where conditions are really pushing them to the brink of survival. Actually, sometimes me too, when I'm trying to follow them too close. But here's the thing: We are the only advanced civilization in the solar system, but that doesn't mean that there is no microbial life nearby. In fact, the planets and moons you see here could host life -- all of them -- and we know that, and it's a strong possibility. And if we were going to find life on those moons and planets, then we would answer questions such as, are we alone in the solar system? Where are we coming from? Do we have family in the neighborhood? Is there life beyond our solar system?
Znate, ponekad najvažnije stvari dolaze u najmanjim pakovanjima. U ovih 15 minuta koje imam, pokušaću da vas ubedim da mikrobi mogu mnogo toga reći o pitanjima kao što je "Da li smo sami?" i mogu mnogo toga reći, ne samo o životu u našem Sunčevom sistemu, već možda i izvan njega, i to je razlog što ih pratim na neverovatna mesta na Zemlji, u ekstremnim sredinama gde ih životni uslovi dovode na sam rub preživljavanja zapravo, ponekad i mene isto tako, kada pokušam da im se previše približim. Ali evo u čemu je stvar: mi smo jedina napredna civilizacija u Sunčevom sistemu ali to ne znači da u okolini nema mikrobskog života. Zapravo, planete i meseci koje ovde vidite mogli bi imati život na sebi - svi oni, i mi to znamo, i velika je verovatnoća da je tako. Pa ako bismo našli život na ovim mesecima i planetama, onda bismo tražili odgovor na pitanja tipa: "Jesmo li sami u Sunčevom sistemu?" "Odakle potičemo?" "Imamo li neku porodicu u komšiluku?" "Ima li života izvan Sunčevog sistema?"
And we can ask all those questions because there has been a revolution in our understanding of what a habitable planet is, and today, a habitable planet is a planet that has a zone where water can stay stable, but to me this is a horizontal definition of habitability, because it involves a distance to a star, but there is another dimension to habitability, and this is a vertical dimension. Think of it as conditions in the subsurface of a planet where you are very far away from a sun, but you still have water, energy, nutrients, which for some of them means food, and a protection. And when you look at the Earth, very far away from any sunlight, deep in the ocean, you have life thriving and it uses only chemistry for life processes.
Možemo da postavimo sva ova pitanja zbog revolucije u našem načinu shvatanja toga šta je zapravo planeta i danas, naseljiva planeta je planeta koja na sebi ima zonu gde voda može ostati stabilna ali po meni to je horizontalna definicija naseljivosti jer uključuje i udaljenost od zvezde, a postoji još jedna dimenzija naseljivosti, a to je ta vertikalna dimenzija. Mislite o njoj kao o uslovima ispod površine planete gde ste veoma udaljeni od Sunca ali još uvek imate vodu, energiju, nutrijente, što za neke od njih znači imati hranu i zaštitu. Kada pogledate Zemlju, veoma daleko od bilo kakve sunčeve svetlosti, duboko u okeanu, i dalje sve vrvi od života koji koristi samo hemiju za životne procese.
So when you think of it at that point, all walls collapse. You have no limitations, basically. And if you have been looking at the headlines lately, then you will see that we have discovered a subsurface ocean on Europa, on Ganymede, on Enceladus, on Titan, and now we are finding a geyser and hot springs on Enceladus, Our solar system is turning into a giant spa. For anybody who has gone to a spa knows how much microbes like that, right? (Laughter)
Pa kada razmišljamo na ovakav način, sve prepreke se ruše. Praktično nema ograničenja. I ako ste u skorije vreme gledali naslove u novinama, onda ste videli da smo otkrili podpovršinski okean na Evropi, Ganimedu, Enceladu, Titanu, i sada istražujemo gejzir i vrele izvore na Enceladusu. Naš Sunčev sistem se pretvara u džinovski spa centar. Svi oni koji su išli u spa centar znaju koliko mikrobi to vole, zar ne? (Smeh)
So at that point, think also about Mars. There is no life possible at the surface of Mars today, but it might still be hiding underground.
Pa na taj način, razmislimo i o Marsu. Život na Marsu nije moguć danas, ali moguće je da se on krije ispod njegove površine.
So, we have been making progress in our understanding of habitability, but we also have been making progress in our understanding of what the signatures of life are on Earth. And you can have what we call organic molecules, and these are the bricks of life, and you can have fossils, and you can minerals, biominerals, which is due to the reaction between bacteria and rocks, and of course you can have gases in the atmosphere. And when you look at those tiny green algae on the right of the slide here, they are the direct descendants of those who have been pumping oxygen a billion years ago in the atmosphere of the Earth. When they did that, they poisoned 90 percent of the life at the surface of the Earth, but they are the reason why you are breathing this air today.
Dakle, napredovali smo u našem razumevanju naseljivosti, ali smo isto tako napredovali u našem razumevanju i toga šta predstavlja život na Zemlji. Imamo ono što nazivamo organskim molekulima, i oni su temelji života, imamo fosile, minerale, biominerale, koji nastaju u reakciji između bakterija i stena, i naravno, imamo gasove u atmosferi. I ove sićušne zelene alge ovde, na desnoj strani stene, one su direktni potomci onih koje su pumpale kiseonik milijardu godina ranije u Zemljinu atmosferu. Kada su to radile, one su otrovale 90 odsto života na Zemljinoj površini, ali one su razlog zašto danas udišemo ovakav vazduh.
But as much as our understanding grows of all of these things, there is one question we still cannot answer, and this is, where are we coming from? And you know, it's getting worse, because we won't be able to find the physical evidence of where we are coming from on this planet, and the reason being is that anything that is older than four billion years is gone. All record is gone, erased by plate tectonics and erosion. This is what I call the Earth's biological horizon. Beyond this horizon we don't know where we are coming from.
Ali iako naše razumevanje o svim ovim stvarima raste, postoji jedno pitanje na koje još uvek nemamo odgovor, a to je - odakle potičemo? Kao što znate, postaje još teže, jer nećemo moći da nađemo fizičke dokaze o našem poreklu na ovoj planeti, a razlog je taj što je sve što je starije od četiri milijarde godina izgubljeno. Svi podaci su izgubljeni, izbrisali su ih tektonika ploča i erozija. Ovo je ono što ja nazivam bilološkim horizontom. Van ovog horizonta, ne znamo odakle dolazimo.
So is everything lost? Well, maybe not. And we might be able to find evidence of our own origin in the most unlikely place, and this place in Mars.
Pa je li sve izgubljeno? Možda i nije. Možda bismo i mogli naći dokaze o našem poreklu na neočekivanim mestima, a takvo mesto je Mars.
How is this possible? Well clearly at the beginning of the solar system, Mars and the Earth were bombarded by giant asteroids and comets, and there were ejecta from these impacts all over the place. Earth and Mars kept throwing rocks at each other for a very long time. Pieces of rocks landed on the Earth. Pieces of the Earth landed on Mars. So clearly, those two planets may have been seeded by the same material. So yeah, maybe Granddady is sitting there on the surface and waiting for us. But that also means that we can go to Mars and try to find traces of our own origin. Mars may hold that secret for us. This is why Mars is so special to us.
Kako je to moguće? Pa, očigledno na početku Sunčevog sistema, Mars i Zemlja su bombardovani ogromnim asteroidima i kometama, i ostaci ovih udara su bili svuda naokolo. Zemlja i Mars su još dugo nastavili da se gađaju stenama. Delovi stena su sleteli na Zemlju. Delovi Zemlje su sleteli na Mars. Očigledno, na ove dve planete moglo je biti posejano seme istog materijala. Stoga, da, možda je neki predak sedeo ovde na ovoj površini i čekao nas. Ali to znači i da možemo otići na Mars i probati da nađemo tragove našeg porekla. Mars možda skriva tu tajnu. To je razlog što nam je Mars tako poseban.
But for that to happen, Mars needed to be habitable at the time when conditions were right. So was Mars habitable? We have a number of missions telling us exactly the same thing today. At the time when life appeared on the Earth, Mars did have an ocean, it had volcanoes, it had lakes, and it had deltas like the beautiful picture you see here. This picture was sent by the Curiosity rover only a few weeks ago. It shows the remnants of a delta, and this picture tells us something: water was abundant and stayed founting at the surface for a very long time. This is good news for life. Life chemistry takes a long time to actually happen.
Ali da bi se to dogodilo, Mars je morao da bude naseljiv u vreme kada su uslovi bili ispunjeni. Pa da li je Mars bio naseljiv? Veliki broj misija na Marsu nam danas pokazuje istu stvar. U vreme kada se život na Zemlji pojavio, Mars je imao okeane, vulkane, jezera, i delte kao na ovoj lepoj slici koju vidite ovde. Ovu sliku je poslao rover Kjuriositi pre samo nekoliko nedelja. Ona pokazuje ostatke delte, i ona nam nešto govori: vode je bilo u izoblju i prekrivala je njegovu površinu veoma dugo. Ovo su dobre vesti za život. Hemiji života potrebno je mnogo vremena da proradi.
So this is extremely good news, but does that mean that if we go there, life will be easy to find on Mars? Not necessarily.
Ovo su dakle jako dobre vesti, ali znači li to da ćemo lako naći život na Marsu ako odemo tamo? Ne obavezno.
Here's what happened: At the time when life exploded at the surface of the Earth, then everything went south for Mars, literally. The atmosphere was stripped away by solar winds, Mars lost its magnetosphere, and then cosmic rays and U.V. bombarded the surface and water escaped to space and went underground. So if we want to be able to understand, if we want to be able to find those traces of the signatures of life at the surface of Mars, if they are there, we need to understand what was the impact of each of these events on the preservation of its record. Only then will we be able to know where those signatures are hiding, and only then will we be able to send our rover to the right places where we can sample those rocks that may be telling us something really important about who we are, or, if not, maybe telling us that somewhere, independently, life has appeared on another planet.
Evo šta se dogodilo: u vreme kada je život probujao na površini Zemlje, na Marsu je sve pošlo naopako, bukvalno. Atmosfera je oduvana solarnim vetrovima, Mars je izgubio svoju magnetosferu, a zatim su kosmičko zračenje i UV zraci bombardovali površinu, a voda je pobegla u atmosferu i otišla ispod površine. Tako, ako želimo da razumemo, ako želimo da nađemo te tragove života na površini Marsa, ako su tamo, moramo da razumemo kakav je bio uticaj svih ovih dešavanja na očuvanje tih dokaza. Samo tako ćemo moći da znamo gde se ti tragovi kriju, i samo tako ćemo moći da pošaljemo rover na prava mesta gde može sakupljati stene koje nam možda mogu reći nešto zaista važno o tome ko smo mi, ili, ako ne, možda nam reći da se negde, nezavisno od nas, život pojavio na drugoj planeti.
So to do that, it's easy. You only need to go back 3.5 billion years ago in the past of a planet. We just need a time machine.
Lako je to uraditi. Samo treba otići 3,5 milijarde godina unazad u prošlost planete. Samo nam treba vremeska mašina.
Easy, right? Well, actually, it is. Look around you -- that's planet Earth. This is our time machine. Geologists are using it to go back in the past of our own planet. I am using it a little bit differently. I use planet Earth to go in very extreme environments where conditions were similar to those of Mars at the time when the climate changed, and there I'm trying to understand what happened. What are the signatures of life? What is left? How are we going to find it? So for one moment now I'm going to take you with me on a trip into that time machine.
Lako, zar ne? Pa, zapravo, i jeste. Pogledajte oko sebe - to je planeta Zemlja. To je naša vremenska mašina. Geolozi je koriste da se vrate u prošlost naše planete. Ja je koristim malo drugačije. Koristim planetu Zemlju da idem u veoma ekstremna okruženja gde su uslovi slični onima koji su bili na Marsu u vreme kada se klima menjala, i tamo pokušavam da razumem šta se dogodilo. Koji su to znakovi života? Šta je ostalo? Kako to pronaći? Sada ću vas nakratko povesti sa sobom na putovanje tom vremenskom mašinom.
And now, what you see here, we are at 4,500 meters in the Andes, but in fact we are less than a billion years after the Earth and Mars formed. The Earth and Mars will have looked pretty much exactly like that -- volcanoes everywhere, evaporating lakes everywhere, minerals, hot springs, and then you see those mounds on the shore of those lakes? Those are built by the descendants of the first organisms that gave us the first fossil on Earth.
I sada, ovo što vidite, mi smo 4 500 metara visoko na Andima ali smo zapravo u dobu od manje od milijardu godina nakon nastanka Zemlje i Marsa. Zemlja i Mars bi izgledali prilično slično ovome - svuda naokolo vuklani, svuda naokolo jezera isparavaju, minerali, vreli izvori, i vidite li ove nasipe na obalama jezera? Njih su stvorili potomci prvih organizama
But if we want to understand what's going on, we need to go a little further. And the other thing about those sites is that exactly like on Mars three and a half billion years ago, the climate is changing very fast, and water and ice are disappearing. But we need to go back to that time when everything changed on Mars, and to do that, we need to go higher. Why is that? Because when you go higher, the atmosphere is getting thinner, it's getting more unstable, the temperature is getting cooler, and you have a lot more U.V. radiation. Basically, you are getting to those conditions on Mars when everything changed.
koji su nam dali prve fosile na Zemlji. Ali ako želimo da razumemo šta se događa, moramo da idemo malo dalje. Još jedna zanimljiva osobina ovih mesta je sto što se ovde, baš kao i na Marsu pre tri i po milijarde godina klima menjala veoma brzo, i voda i led su nestajali. Ali moramo da se vratimo unazad u to vreme kada se sve na Marsu promenilo, i da bismo to uradili, moramo da se popnemo još više. Zašto? Jer kada se penjemo više, atmosfera se stanjuje, postaje nestabilnija, temperatura je hladnija, i ima više UV zračenja. U suštini, približavamo se onim uslovima na Marsu kada se sve menjalo.
So I was not promising anything about a leisurely trip on the time machine. You are not going to be sitting in that time machine. You have to haul 1,000 pounds of equipment to the summit of this 20,000-foot volcano in the Andes here. That's about 6,000 meters. And you also have to sleep on 42-degree slopes and really hope that there won't be any earthquake that night. But when we get to the summit, we actually find the lake we came for. At this altitude, this lake is experiencing exactly the same conditions as those on Mars three and a half billion years ago. And now we have to change our voyage into an inner voyage inside that lake, and to do that, we have to remove our mountain gear and actually don suits and go for it. But at the time we enter that lake, at the very moment we enter that lake, we are stepping back three and a half billion years in the past of another planet, and then we are going to get the answer came for. Life is everywhere, absolutely everywhere. Everything you see in this picture is a living organism. Maybe not so the diver, but everything else. But this picture is very deceiving. Life is abundant in those lakes, but like in many places on Earth right now and due to climate change, there is a huge loss in biodiversity. In the samples that we took back home, 36 percent of the bacteria in those lakes were composed of three species, and those three species are the ones that have survived so far.
Pa, nisam obećala lagodno putovanje ovom vremenskom mašinom. Nećete samo sedeti u njoj. Morate vući 450 kg opreme do vrha ovog vulkana na Andima visokog 20 000 stopa. To je oko 6000 metara. Takođe morate da spavate na padini pod uglom od 42 stepena, i nadate se da neće biti nikakvih zemljotresa preko noći. Ali kada stignemo do vrha, naći ćemo jezero koje tražimo. Na ovoj visini, ovo jezero se nalazi u istim uslovima kao što su bili oni na Marsu tri i po milijarde godina ranije. I sada moramo da menjamo ovo naše putovanje u putovanje u unutrašnjost ovog jezera, i da bismo to uradili, moramo da uklonimo planinsku opremu, navučemo odela i idemo. Ali kada uđemo u jezero, baš u trenutku kada zaronimo unutar, vraćamo se unazad tri i po milijarde godina u prošlost neke druge planete, i tada ćemo dobiti odgovor po koji smo došli. Života ima svuda, baš svuda. Sve što na ovoj slici vidite je neki živi organizam. Možda ne treba da računamo ronioca, ali sve ostalo, da. Ali ova slika je veoma obmanjujuća. Života ima u izoblju u ovim jezerima, ali kao na većini mesta na Zemlji danas, zbog klimatskih promena, i ovde dolazi do ogromnog smanjenja biodiverziteta. U uzorcima koje smo odneli, 36 odsto bakterija iz ovih jezera sastojalo se od tri vrste, i te tri vrste su one koje su tako dugo preživele.
Here's another lake, right next to the first one. The red color you see here is not due to minerals. It's actually due to the presence of a tiny algae. In this region, the U.V. radiation is really nasty. Anywhere on Earth, 11 is considered to be extreme. During U.V. storms there, the U.V. Index reaches 43. SPF 30 is not going to do anything to you over there, and the water is so transparent in those lakes that the algae has nowhere to hide, really, and so they are developing their own sunscreen, and this is the red color you see. But they can adapt only so far, and then when all the water is gone from the surface, microbes have only one solution left: They go underground. And those microbes, the rocks you see in that slide here, well, they are actually living inside rocks and they are using the protection of the translucence of the rocks to get the good part of the U.V. and discard the part that could actually damage their DNA. And this is why we are taking our rover to train them to search for life on Mars in these areas, because if there was life on Mars three and a half billion years ago, it had to use the same strategy to actually protect itself. Now, it is pretty obvious that going to extreme environments is helping us very much for the exploration of Mars and to prepare missions. So far, it has helped us to understand the geology of Mars. It has helped to understand the past climate of Mars and its evolution, but also its habitability potential. Our most recent rover on Mars has discovered traces of organics. Yeah, there are organics at the surface of Mars. And it also discovered traces of methane. And we don't know yet if the methane in question is really from geology or biology. Regardless, what we know is that because of the discovery, the hypothesis that there is still life present on Mars today remains a viable one.
Evo ga još jedno jezero, odmah pored prvog. Crvena boja koju vidite ne potiče od minerala. Ona je zapravo ovakva zbog prisustva sićušnih algi. U ovoj oblasti, UV zračenje je jako gadno. Bilo gde na Zemlji, 11 se smatra ekstremnim. Tokom UV oluja ovde, UV indeks dostiže 43. Faktor zaštite 30 neće vam ovde ništa pomoći. Voda je tako prozirna u ovim jezerima da alge bukvalno nemaju gde da se sakriju, pa su razvile svoju sopstvenu kremu za sunčanje, i to je ova crvena boja koju vidite. Ali one mogu da se prilagode samo donekle, i kada sva voda nestane sa površine, mikrobima preostaje samo jedno rešenje: da idu ispod površine. I ovi mikrobi, stene koje vidite na ovom slajdu, pa, mikrobi zapravo žive unutar tih stena i od njih koriste zaštitu od prozračnosti da bi dobili dobar deo UV zraka i odbacili deo koji zapravo može da ošteti DNK. To je razlog što koristimo rovere i treniramo ih da traže život na Marsu u ovakvim oblastima, jer ako je bilo života na Marsu tri i po milijarde godina ranije, morao je da se koristi istom strategijom da bi se zaštitio. Sada, prilično je očigledno da nam odlazak u ekstremna životna okruženja dosta pomaže u istraživanju Marsa, i u pripremama misija. Za sada, pomogao nam je da razumemo geologiju Marsa. Pomogao nam je da razumemo prošlost klime na Marsu i njegovu evoluciju, ali i njegov potencijal za naseljivost. Naš poslednji rover je na Marsu otkrio tragove organskih materija. Da, organske materije postoje na površini Marsa. Takođe je otkrio tragove metana. I mi još uvek ne znamo da li je taj metan zapravo pitanje za biologiju ili geologiju. Bez obzira na to, ono što znamo je da zahvaljujući tom otkriću, hipoteza da na Marsu i dalje ima života ostaje održiva.
So by now, I think I have convinced you that Mars is very special to us, but it would be a mistake to think that Mars is the only place in the solar system that is interesting to find potential microbial life. And the reason is because Mars and the Earth could have a common root to their tree of life, but when you go beyond Mars, it's not that easy. Celestial mechanics is not making it so easy for an exchange of material between planets, and so if we were to discover life on those planets, it would be different from us. It would be a different type of life. But in the end, it might be just us, it might be us and Mars, or it can be many trees of life in the solar system. I don't know the answer yet, but I can tell you something: No matter what the result is, no matter what that magic number is, it is going to give us a standard by which we are going to be able to measure the life potential, abundance and diversity beyond our own solar system. And this can be achieved by our generation. This can be our legacy, but only if we dare to explore.
Pa mislim da sam vas do sada ubedila da nam je Mars veoma poseban, ali bilo bi pogrešno misliti da je Mars jedino mesto u Sunčevom sistemu zanimljivo za traženje potencijalnog mikrobskog života. A razlog za to je taj što Mars i Zemlja mogu imati zajednički koren njihovog drveta života, ali kada se udaljavamo od Marsa, to ne ide tako lako. Nebeska mehanika nam baš i ne olakšava razmenu materijala između planeta, i ako bismo otkrili život na tim planetama, on bi bio drugačiji od našeg. Bio bi to drugačiji tip života. Ali na kraju, može biti da smo tu samo mi, može biti da smo tu mi i Mars, a može biti i da postoji mnogo drveća života u sunčevom sistemu. Ne znam još uvek odgovor na ovo, ali mogu vam nešto reći: koji god da je rezultat, koji god da je taj magični broj, on će nam dati standard prema kojem će biti moguće izmeriti životni potencijal, obilje i različitost van granica našeg Sunčevog sistema. I ovo se može postići u našoj generaciji. To može biti naša zaostavština, ali samo ako budemo istraživali.
Now, finally, if somebody tells you that looking for alien microbes is not cool because you cannot have a philosophical conversation with them, let me show you why and how you can tell them they're wrong. Well, organic material is going to tell you about environment, about complexity and about diversity. DNA, or any information carrier, is going to tell you about adaptation, about evolution, about survival, about planetary changes and about the transfer of information. All together, they are telling us what started as a microbial pathway, and why what started as a microbial pathway sometimes ends up as a civilization or sometimes ends up as a dead end.
Sada, konačno, ako bi vam neko rekao da traženje vanzemaljskih mikroba nije kul jer ne možemo sa njima uspostaviti filozofski razgovor, dopustite da vam pokažem zašto i kako biste im mogli reći da nisu u pravu. Pa, organski materijali će vam govoriti o okruženju, o složenosti i o različitosti. DNK, ili bilo koji nosilac informacija, govoriće o prilagođavanju o evoluciji, o preživljavanju, o promenama na planeti i o prenosu informacija. Sve zajedno, govore nam o onome što je počelo kao put mikroba, i zašto je počelo baš tako, ponekad vodeći do civilizacije, a ponekad vodeći do ćorsokaka.
Look at the solar system, and look at the Earth. On Earth, there are many intelligent species, but only one has achieved technology. Right here in the journey of our own solar system, there is a very, very powerful message that says here's how we should look for alien life, small and big. So yeah, microbes are talking and we are listening, and they are taking us, one planet at a time and one moon at a time, towards their big brothers out there. And they are telling us about diversity, they are telling us about abundance of life, and they are telling us how this life has survived thus far to reach civilization, intelligence, technology and, indeed, philosophy.
Pogledajte naš Sunčev sistem, i pogledajte Zemlju. Na Zemlji, postoje mnoge inteligentne vrste, ali samo je jedna dostigla tehnologiju. Sada u ovom putovanju kroz naš Sunčev sistem, nalazimo jednu veoma snažnu poruku koja kaže kako bi trebalo da tražimo vanzemaljski život, i mali i veliki. I da, mikrobi mogu da govore, a mi slušamo, i oni nas vode od planete do planete, od meseca do meseca, tamo negde, do njihove velike braće. Oni nam govore i o raznovrsnosti, govore nam o obilju života, i govore nam o tome kako se život ovako dugo održao da bi dostigao civilizaciju, inteligenciju, tehnologiju, i zaista, filozofiju.
Thank you.
Hvala vam.
(Applause)
(Aplauz)