I'm really glad to be here. I'm glad you're here, because that would be a little weird. I'm glad we're all here. And by "here," I don't mean here. Or here. But here. I mean Earth. And by "we," I don't mean those of us in this auditorium, but life, all life on Earth --
Baš mi je drago što sam ovde. Drago mi je što ste vi ovde, inače bi bilo malčice čudno. Drago mi je što smo svi ovde. A pod "ovde", ne mislim na ovde. Ili ovde. Već ovde. Mislim na Zemlju. I pod "mi" ne mislim na nas u auditorijumu, već na život, sav život na Zemlji -
(Laughter)
(Smeh)
from complex to single-celled, from mold to mushrooms to flying bears.
od složenog do jednoćelijskog, od buđi preko pečuraka do letećih medveda.
(Laughter)
(Smeh)
The interesting thing is, Earth is the only place we know of that has life -- 8.7 million species. We've looked other places, maybe not as hard as we should or we could, but we've looked and haven't found any; Earth is the only place we know of with life. Is Earth special? This is a question I've wanted to know the answer to since I was a small child, and I suspect 80 percent of this auditorium has thought the same thing and also wanted to know the answer. To understand whether there are any planets -- out there in our solar system or beyond -- that can support life, the first step is to understand what life here requires.
Zanimljivo da je Zemlja jedino poznato mesto na kom ima života - 8,7 miliona vrsta. Tražili smo druga mesta, možda ne onoliko koliko smo trebali ili mogli, ali tražili smo i nismo našli bilo šta; Zemlja je jedino nama poznato mesto sa životom. Da li je Zemlja posebna? Odgovor na ovo pitanje sam želeo da znam od svog ranog detinjstva, i pretpostavljam da 80% ovog auditorijuma je pomislilo isto to i takođe je želelo da zna odgovor. Da bismo razumeli ima li još nekih planeta - u našem solarnom sistemu i dalje - koje mogu da održavaju život, prvi korak je u razumevanju šta je neophodno za život.
It turns out, of all of those 8.7 million species, life only needs three things. On one side, all life on Earth needs energy. Complex life like us derives our energy from the sun, but life deep underground can get its energy from things like chemical reactions. There are a number of different energy sources available on all planets. On the other side, all life needs food or nourishment. And this seems like a tall order, especially if you want a succulent tomato.
Ispostavilo se da su za život svih 8,7 miliona vrsta potrebne tri stvari. S jedne strane, svem životu na Zemlji je potrebna energija. Složeni život poput našeg dobija energiju od sunca, ali život duboko pod zemljom dobija energiju od, recimo, hemijskih reakcija. Ima više različitih izvora energije dostupnih na svim planetama. S druge strane, svem životu je potrebna hrana ili ishrana. A ovo se čini kao težak zadatak, naročito ako želite sočan paradajz.
(Laughter)
(Smeh)
However, all life on Earth derives its nourishment from only six chemical elements, and these elements can be found on any planetary body in our solar system. So that leaves the thing in the middle as the tall pole, the thing that's hardest to achieve. Not moose, but water.
Međutim, sav život na Zemlji dobija hranu iz svega šest hemijskih elemenata, a ovi elementi su prisutni na bilo kojoj planeti u našem solarnom sistemu. Te je zbog toga ovo u sredini težak zadatak, nešto što je najteže postići. Ne los, već voda.
(Laughter)
(Smeh)
Although moose would be pretty cool.
Iako bi los bio baš super.
(Laughter)
(Smeh)
And not frozen water, and not water in a gaseous state, but liquid water. This is what life needs to survive, all life. And many solar system bodies don't have liquid water, and so we don't look there. Other solar system bodies might have abundant liquid water, even more than Earth, but it's trapped beneath an icy shell, and so it's hard to access, it's hard to get to, it's hard to even find out if there's any life there.
I to ne zamrznuta voda, i ne voda u gasovitom stanju, već tečna voda. Ovo je potrebno životu za opstanak, svem životu. A mnoga tela u solarnom sistemu nemaju tečnu vodu, te zato tamo ne tražimo život. Druga tela u solarnom sistemu mogu da imaju obilje tečne vode, čak i više nego Zemlja, ali je ona zarobljena ispod ledene opne, te je teško njoj pristupiti, teško je doći do nje, teško je čak i saznati da li tamo uopšte ima života.
So that leaves a few bodies that we should think about. So let's make the problem simpler for ourselves. Let's think only about liquid water on the surface of a planet. There are only three bodies to think about in our solar system, with regard to liquid water on the surface of a planet, and in order of distance from the sun, it's: Venus, Earth and Mars. You want to have an atmosphere for water to be liquid. You have to be very careful with that atmosphere. You can't have too much atmosphere, too thick or too warm an atmosphere, because then you end up too hot like Venus, and you can't have liquid water. But if you have too little atmosphere and it's too thin and too cold, you end up like Mars, too cold. So Venus is too hot, Mars is too cold, and Earth is just right. You can look at these images behind me and you can see automatically where life can survive in our solar system. It's a Goldilocks-type problem, and it's so simple that a child could understand it.
Stoga nam ostaje nekoliko tela o kojima bi trebalo da mislimo. Zato pojednostavimo problem zbog nas. Razmišljajmo jedino o tečnoj vodi na površini planete. Možemo da razmišljamo o svega tri tela u našem solarnom sistemu, u smislu tečne vode na površini planete, a prema udaljenosti od sunca to su: Venera, Zemlja i Mars. Potrebna vam je atmosfera da bi voda bila tečna. Morate da budete veoma oprezni s tom atmosferom. Ne treba vam previše atmosfere, pregusta ili pretopla atmosfera jer bi bilo suviše vrelo, kao na Veneri i ne biste imali tečnu vodu. Ali ako imate premalo atmosfere i ona je suviše retka i hladna, završite kao Mars, suviše hladni. Dakle, Venera je pretopla, Mars je prehladan, a Zemlja je potaman. Posmatrajući ove slike iza mene, možete automatski da vidite gde je moguć opstanak života u našem solarnom sistemu. To je tip problema "Zlatokosa", i toliko je jednostavan da dete može da ga razume.
However, I'd like to remind you of two things from the Goldilocks story that we may not think about so often but that I think are really relevant here. Number one: if Mama Bear's bowl is too cold when Goldilocks walks into the room, does that mean it's always been too cold? Or could it have been just right at some other time? When Goldilocks walks into the room determines the answer that we get in the story. And the same is true with planets. They're not static things. They change. They vary. They evolve. And atmospheres do the same. So let me give you an example.
Međutim, voleo bih da vas podsetim na dve stvari iz priče o Zlatokosoj o kojima možda ne razmišljamo tako često, ali smatram da su zaista važne ovde. Pod jedan: ako je činija mame medved suviše hladna kad Zlatokosa uđe u prostoriju, da li to znači da je oduvek bila hladna? Ili je u nekom drugom vremenu bila baš kako treba? Kad Zlatokosa uđe u prostoriju određuje odgovor koji nam priča pruža. A isto je tako i s planetama. One nisu nešto statično. Menjaju se. Variraju. Razvijaju se. A isto je i sa atmosferama. Stoga ću da vam dam jedan primer.
Here's one of my favorite pictures of Mars. It's not the highest resolution image, it's not the sexiest image, it's not the most recent image, but it's an image that shows riverbeds cut into the surface of the planet; riverbeds carved by flowing, liquid water; riverbeds that take hundreds or thousands or tens of thousands of years to form. This can't happen on Mars today. The atmosphere of Mars today is too thin and too cold for water to be stable as a liquid. This one image tells you that the atmosphere of Mars changed, and it changed in big ways. And it changed from a state that we would define as habitable, because the three requirements for life were present long ago. Where did that atmosphere go that allowed water to be liquid at the surface?
Ovo je među mojim omiljenim slikama Marsa. Nije to slika naročito visoke rezolucije, nije ni naročito seksi, nije najskorija slika, ali je slika koja pokazuje rečna korita kako seku površinu planete; rečna korita koja je urezala tekuća, tečna voda; korita koja su se oblikovala stotinama ili hiljadama ili desetinama hiljada godina. Ovo više nije moguće na Marsu. Danas je atmosfera na Marsu suviše retka i hladna da bi voda bila postojana kao tečnost. Ova slika vam govori da se atmosfera na Marsu promenila, i to se promenila uveliko. A promenila se iz stanja koje bismo odredili kao nastanjivo, jer su tri uslova za život nekad davno bila prisutna. Gde je nestala ta atmosfera koja je omogućavala vodi da bude tečna na površini?
Well, one idea is it escaped away to space. Atmospheric particles got enough energy to break free from the gravity of the planet, escaping away to space, never to return. And this happens with all bodies with atmospheres. Comets have tails that are incredibly visible reminders of atmospheric escape. But Venus also has an atmosphere that escapes with time, and Mars and Earth as well. It's just a matter of degree and a matter of scale. So we'd like to figure out how much escaped over time so we can explain this transition.
Pa, jedna od ideja je da je izmakla u svemir. Atmosferske čestice su dobile dovoljno energije da se oslobode gravitacije planete, izmičući u svemir, bespovratno. A to se dešava svim telima s atmosferama. Komete imaju repove koji su izuzetno očiti podsetnici izmicanja atmosfere. Ali Venera takođe ima atmosferu koja vremenom izmiče, kao i Mars i Zemlja. Prosto se radi o stepenu i razmeri. Pa bismo voleli da otkrijemo koliko je izmaklo vremenom, kako bismo mogli da objasnimo ovaj prelaz.
How do atmospheres get their energy for escape? How do particles get enough energy to escape? There are two ways, if we're going to reduce things a little bit. Number one, sunlight. Light emitted from the sun can be absorbed by atmospheric particles and warm the particles. Yes, I'm dancing, but they --
Kako atmosfere dobijaju energiju za beg? Kako čestice dobiju dovoljno energije za beg? Postoje dva načina, ako bismo želeli da malo sažmemo stvari. Prvo: sunčeva svetlost. Svetlost koju odašilja sunce mogu da apsorbuju atmosferske čestice čime se one zagrejavaju. Da, plešem, ali one -
(Laughter)
(Smeh)
Oh my God, not even at my wedding.
Oh, gospode, nisam ni na svom venčanju.
(Laughter)
(Smeh)
They get enough energy to escape and break free from the gravity of the planet just by warming. A second way they can get energy is from the solar wind. These are particles, mass, material, spit out from the surface of the sun, and they go screaming through the solar system at 400 kilometers per second, sometimes faster during solar storms, and they go hurtling through interplanetary space towards planets and their atmospheres, and they may provide energy for atmospheric particles to escape as well.
Dobiju dovoljno energije da umaknu i oslobode se od gravitacije planete, pukim zagrevanjem. Drugi način na koji mogu da dobiju energiju je solarni vetar. Ovo su čestice, mase, materijali koje su ispljunute sa površine sunca i one jurcaju kroz solarni sistem 400 kilometara u sekundi, ponekad i brže tokom solarnih oluja i one hrle kroz međuplanetarni prostor ka planetama i njihovim atmosferama, a mogu i da pruže energiju atmosferskim česticama da bi i one umakle.
This is something that I'm interested in, because it relates to habitability. I mentioned that there were two things about the Goldilocks story that I wanted to bring to your attention and remind you about, and the second one is a little bit more subtle. If Papa Bear's bowl is too hot, and Mama Bear's bowl is too cold, shouldn't Baby Bear's bowl be even colder if we're following the trend? This thing that you've accepted your entire life, when you think about it a little bit more, may not be so simple. And of course, distance of a planet from the sun determines its temperature. This has to play into habitability. But maybe there are other things we should be thinking about. Maybe it's the bowls themselves that are also helping to determine the outcome in the story, what is just right.
Ovo je nešto za šta sam zainteresovan jer ima veze s nastanjivošću. Pomenuo sam dve stvari iz priče o Zlatokosoj na koje želim da vam skrenem pažnju i da vas podsetim na njih, a druga je malčice finija. Ako je činija tate medveda suviše vrela, a činija mame medveda je suviše hladna, zar ne bi trebalo da je činija bebe medveda čak i hladnija, ukoliko pratimo trend? Nešto što ste prihvatili čitav vaš život, kad razmislite o tome malo više, možda i nije tako prosto. I naravno da udaljenost planete od sunca određuje njenu temperaturu. Ovo se odražava na nastanjivost. Ali možda ima nešto drugo o čemu bi trebalo da mislimo. Možda se radi o samim činijama koje takođe pomažu u određivanju ishoda priče, šta je taman kako treba.
I could talk to you about a lot of different characteristics of these three planets that may influence habitability, but for selfish reasons related to my own research and the fact that I'm standing up here holding the clicker and you're not --
Mogao bih mnogo da vam govorim o različitim osobinama ove tri planete, koje možda utiču na nastanjivost, ali iz sebičnih razloga u vezi s mojim istraživanjem, i zbog činjenice da ja stojim ovde gore i držim daljinski, a ne vi -
(Laughter)
(Smeh)
I would like to talk for just a minute or two about magnetic fields. Earth has one; Venus and Mars do not. Magnetic fields are generated in the deep interior of a planet by electrically conducting churning fluid material that creates this big old magnetic field that surrounds Earth. If you have a compass, you know which way north is. Venus and Mars don't have that. If you have a compass on Venus and Mars, congratulations, you're lost.
želeo bih da govorim samo minut ili dva o magnetnim poljima. Zemlja ga ima; Venera i Mars nemaju. Magnetna polja nastaju u dubokoj unutrašnjosti planete električnim provođenjem uskovitlanih tečnih materijala što stvara veliko staro magnetno polje koje okružuje Zemlju. Ako imate kompas, znate na kojoj strani je sever. Venera i Mars to nemaju. Ako imate kompas na Veneri i Marsu, čestitam, zalutali ste.
(Laughter)
(Smeh)
Does this influence habitability? Well, how might it? Many scientists think that a magnetic field of a planet serves as a shield for the atmosphere, deflecting solar wind particles around the planet in a bit of a force field-type effect having to do with electric charge of those particles. I like to think of it instead as a salad bar sneeze guard for planets.
Da li ovo utiče na nastanjivost? Pa, kako bi moglo? Mnogi naučnici smatraju da magnetno polje planete služi kao štit za atmosferu, koji odbija čestice solarnih vetrova oko planete u nekoj vrsti blagog efekta sile polja koja je u vezi sa električnim nabojem tih čestica. Pre to vidim kao o zaklonu od kašlja za planete u vidu šanka za salatu.
(Laughter)
(Smeh)
And yes, my colleagues who watch this later will realize this is the first time in the history of our community that the solar wind has been equated with mucus.
I da, moje kolege, koje će ovo kasnije da gledaju, će uvideti da je ovo prvi put u istoriji naše zajednice da je solarni vetar poistovećen sa sluzi.
(Laughter)
(Smeh)
OK, so the effect, then, is that Earth may have been protected for billions of years, because we've had a magnetic field. Atmosphere hasn't been able to escape. Mars, on the other hand, has been unprotected because of its lack of magnetic field, and over billions of years, maybe enough atmosphere has been stripped away to account for a transition from a habitable planet to the planet that we see today.
U redu, posledica toga je da je Zemlja možda zaštićena milijardama godina jer ima magnetno polje. Atmosfera nije mogla da umakne. Mars, s druge strane, je bio nezaštićen zbog nedostatka magnetnog polja, i tokom milijardi godina je možda dovoljna količina atmosfere guljena do te mere da on pređe iz nastanjive planete do planete koju vidimo danas.
Other scientists think that magnetic fields may act more like the sails on a ship, enabling the planet to interact with more energy from the solar wind than the planet would have been able to interact with by itself. The sails may gather energy from the solar wind. The magnetic field may gather energy from the solar wind that allows even more atmospheric escape to happen. It's an idea that has to be tested, but the effect and how it works seems apparent. That's because we know energy from the solar wind is being deposited into our atmosphere here on Earth. That energy is conducted along magnetic field lines down into the polar regions, resulting in incredibly beautiful aurora. If you've ever experienced them, it's magnificent. We know the energy is getting in. We're trying to measure how many particles are getting out and if the magnetic field is influencing this in any way.
Drugi naučnici smatraju da magnetna polja možda deluju poput jedara na brodu, koja omogućuju planeti da interaguje s više energije iz solarnih vetrova nego što bi planeta sama bila u stanju da interaguje. Jedra možda sakupljaju energiju iz solarnog vetra. Magnetno polje možda sakuplja energiju iz solarnog vetra koja omogućuje da se još više atmosferskog izmicanja desi. To je zamisao koja mora da se testira, ali njeni efekti i to kako deluje se čine očiglednim. To je zato što znamo da se energija iz solarnog vetra skladišti u našoj atmosferi ovde na Zemlji. Ta energija se sprovodi duž linija magnetnog polja dole do polarnih oblasti, rezultirajući predivnom polarnom svetlošću. Ako ste to iskusili, veličanstveno je. Znamo da energija dolazi unutra. Pokušavamo da izmerimo koliko čestica izlazi napolje i da li magnetno polje na bilo koji način utiče na to.
So I've posed a problem for you here, but I don't have a solution yet. We don't have a solution. But we're working on it. How are we working on it? Well, we've sent spacecraft to all three planets. Some of them are orbiting now, including the MAVEN spacecraft which is currently orbiting Mars, which I'm involved with and which is led here, out of the University of Colorado. It's designed to measure atmospheric escape. We have similar measurements from Venus and Earth. Once we have all our measurements, we can combine all these together, and we can understand how all three planets interact with their space environment, with the surroundings. And we can decide whether magnetic fields are important for habitability or not.
Dakle, postavio sam vam problem ovde, ali još uvek nemam rešenje. Nemamo rešenje. Ali radimo na tome. Kako radimo na tome? Poslali smo kosmičke brodove na sve tri planete. Neki od njih upravo kruže, uključujući svemirski brod MAVEN koji trenutno kruži oko Marsa, u to sam uključen i time se upravlja odavde, sa Univerziteta u Koloradu. Dizajniran je da meri atmosferska izmicanja. Imamo slična merenja sa Venere i Zemlje. Čim dobijemo sva merenja, možemo da kombinujemo sve njih zajedno i možemo da razumemo kako sve tri palente interaguju sa svojim svemirskim okruženjem, sa okolinom. I možemo da odredimo da li su magnetna polja važna za nastanjivost ili nisu.
Once we have that answer, why should you care? I mean, I care deeply ... And financially as well, but deeply.
Zašto biste marili za taj odgovor? Mislim, ja veoma marim... I finansijski, ali veoma.
(Laughter)
(Smeh)
First of all, an answer to this question will teach us more about these three planets, Venus, Earth and Mars, not only about how they interact with their environment today, but how they were billions of years ago, whether they were habitable long ago or not. It will teach us about atmospheres that surround us and that are close. But moreover, what we learn from these planets can be applied to atmospheres everywhere, including planets that we're now observing around other stars. For example, the Kepler spacecraft, which is built and controlled here in Boulder, has been observing a postage stamp-sized region of the sky for a couple years now, and it's found thousands of planets -- in one postage stamp-sized region of the sky that we don't think is any different from any other part of the sky.
Pre svega, odgovorom na ovo pitanje ćemo više naučiti o ove tri planete, Veneri, Zemlji i Marsu, ne samo kako interaguju trenutno sa svojim okruženjima, već kakve su bile pre milijardu godina, da li su nekad davno bile nastanjive ili ne. Naučićemo o atmosferama koje nas okružuju i koje su blizu. Ali, štaviše, ono što naučimo od ovih planeta može da se primeni na atmosfere svuda, uključujući planete koje trenutno posmatramo oko drugih zvezda. Na primer, kosmički brod Kepler, koji je napravljen i njime se upravlja odavde iz Boldera, posmatra predeo neba veličine poštanske markice već nekoliko godina, i otkrio je na hiljade planeta - u jednom predelu neba veličine poštanske markice koji ne smatramo iole različitim od bilo kog drugog dela neba.
We've gone, in 20 years, from knowing of zero planets outside of our solar system, to now having so many, that we don't know which ones to investigate first. Any lever will help. In fact, based on observations that Kepler's taken and other similar observations, we now believe that, of the 200 billion stars in the Milky Way galaxy alone, on average, every star has at least one planet. In addition to that, estimates suggest there are somewhere between 40 billion and 100 billion of those planets that we would define as habitable in just our galaxy.
Prešli smo, za 20 godina, od poznavanja nula planeta van našeg solarnog sistema, do toga da ih imamo toliko, da ne znamo koje prvo da istražujemo. Svako oruđe može da pomogne. Zapravo, na osnovu zapažanja koja je napravio Kepler, i drugih sličnih zapažanja, trenutno verujemo da, od 200 milijardi zvezda samo u galaksiji Mlečni put, u proseku, svaka zvezda ima bar jednu planetu. Uz to, procenjuje se da ima otprilike između 40 milijardi i 100 milijardi planeta koje bismo odredili kao nastanjive samo u našoj galaksiji.
We have the observations of those planets, but we just don't know which ones are habitable yet. It's a little bit like being trapped on a red spot --
Imamo zapažanja s tih planeta, ali prosto još uvek ne znamo koje su nastanjive. Pomalo podseća na zarobljenost na crvenoj tački -
(Laughter)
(Smeh)
on a stage and knowing that there are other worlds out there and desperately wanting to know more about them, wanting to interrogate them and find out if maybe just one or two of them are a little bit like you. You can't do that. You can't go there, not yet. And so you have to use the tools that you've developed around you for Venus, Earth and Mars, and you have to apply them to these other situations, and hope that you're making reasonable inferences from the data, and that you're going to be able to determine the best candidates for habitable planets, and those that are not.
na sceni i saznanje da postoje drugi svetovi tamo negde i na očajničku želju da znate više o njima, želite da ih ispitate i otkrijete da li možda bar jedan ili dva od njih bar malo liče na vas. Ne možete to da učinite. Ne možete i dalje da odete tamo. Te morate da koristite oruđa oko vas koja ste razvili za Veneru, Zemlju i Mars, i morate da ih primenite u tim ostalim situacijama, i da se nadate da izvodite razumne zaključke iz podataka i da ćete biti u stanju da odredite najbolje kandidate za nastanjive planete, i one koji to nisu.
In the end, and for now, at least, this is our red spot, right here. This is the only planet that we know of that's habitable, although very soon we may come to know of more. But for now, this is the only habitable planet, and this is our red spot. I'm really glad we're here.
I, naposletku, bar za sad, ovo je naša crvena tačka - tačno tu. Ovo je jedina planeta za koju znamo da je nastanjiva, iako ćemo veoma brzo saznati za mnoge druge. Ali za sad, ovo je jedina nastanjiva planeta i ovo je naša crvena tačka. Baš mi je drago da smo ovde.
Thanks.
Hvala.
(Applause)
(Aplauz)