Extraordinary claims require extraordinary evidence, and it is my job, my responsibility, as an astronomer to remind people that alien hypotheses should always be a last resort.
Izvanredne tvrdnje zahtevaju izvanredne dokaze, a moj je posao, moja odgovornost kao astronoma, da podsetim ljude da su pretpostavke o vanzemaljcima uvek poslednje uporište.
Now, I want to tell you a story about that. It involves data from a NASA mission, ordinary people and one of the most extraordinary stars in our galaxy.
Sad želim da vam ispričam priču o tome. Ona sadrži podatke sa NASA-ine misije, obične ljude i jednu od najizvanrednijih zvezda u našoj galaksiji.
It began in 2009 with the launch of NASA's Kepler mission. Kepler's main scientific objective was to find planets outside of our solar system. It did this by staring at a single field in the sky, this one, with all the tiny boxes. And in this one field, it monitored the brightness of over 150,000 stars continuously for four years, taking a data point every 30 minutes. It was looking for what astronomers call a transit. This is when the planet's orbit is aligned in our line of sight, just so that the planet crosses in front of a star. And when this happens, it blocks out a tiny bit of starlight, which you can see as a dip in this curve.
Počinje 2009, lansiranjem NASA-ine misije Kepler. Keplerov glavni naučni cilj je bio da pronađe planete van našeg solarnog sistema. On je to radio tako što bi zurio u jedno polje na nebu, ovo, sa svim tim malim poljima. A u ovom polju je nadgledao sjaj preko 150,000 zvezda u kontinuitetu od četiri godine, uzimajući jedinice podataka na svakih 30 minuta. Tražio je ono što astronomi zovu tranzitom. To je kad se planetarna orbita poravna s našom linijom horizonta, prosto se radi o prolasku planete ispred zvezde. A kad se ovo desi, maleni deo zvezdane svetlosti je blokiran, što je prikazano u vidu pada na ovoj krivoj.
And so the team at NASA had developed very sophisticated computers to search for transits in all the Kepler data.
Pa je NASA-ina ekipa razvila veoma prefinjene kompjutere da bi tragali za tranzitima kroz sve Keplerove podatke.
At the same time of the first data release, astronomers at Yale were wondering an interesting thing: What if computers missed something?
Istovremeno sa prvom objavom podataka, astronomi na Jejlu su se zapitali nešto zanimljivo: šta ako je kompjuterima nešto promaklo?
And so we launched the citizen science project called Planet Hunters to have people look at the same data. The human brain has an amazing ability for pattern recognition, sometimes even better than a computer. However, there was a lot of skepticism around this. My colleague, Debra Fischer, founder of the Planet Hunters project, said that people at the time were saying, "You're crazy. There's no way that a computer will miss a signal." And so it was on, the classic human versus machine gamble. And if we found one planet, we would be thrilled. When I joined the team four years ago, we had already found a couple. And today, with the help of over 300,000 science enthusiasts, we have found dozens, and we've also found one of the most mysterious stars in our galaxy.
Te smo pokrenuli projekat građana naučnika pod nazivom Lovci na planete, da bi ljudi pregledali iste te podatke. Ljudski mozak ima neverovatnu sposobnost prepoznavanja obrazaca, ponekad čak i bolju od kompjutera. Međutim, mnogo je bilo skepse oko ovoga. Moja koleginica Debra Fišer, osnivačica projekta Lovci na planete, rekla je da su ljudi tada govorili: "Luda si. Nema šanse da bi kompjuteru promakao signal." Pa je to bila klasična opklada ljudi protiv mašine. A ako bismo pronašli jednu planetu, bili bismo oduševljeni. Kada sam se priključila ekipi pre četiri godine, već smo bili našli nekolike. A do danas smo uz pomoć preko 300,000 naučnih entuzijasta pronašli na desetine, a takođe smo pronašli jednu od najtajanstvenijih zvezda u našoj galaksiji.
So to understand this, let me show you what a normal transit in Kepler data looks like. On this graph on the left-hand side you have the amount of light, and on the bottom is time. The white line is light just from the star, what astronomers call a light curve. Now, when a planet transits a star, it blocks out a little bit of this light, and the depth of this transit reflects the size of the object itself. And so, for example, let's take Jupiter. Planets don't get much bigger than Jupiter. Jupiter will make a one percent drop in a star's brightness. Earth, on the other hand, is 11 times smaller than Jupiter, and the signal is barely visible in the data.
Kako biste razumeli ovo, dozvolite da pokažem kako izgleda normalan tranzit u Keplerovim podacima. Na ovom grafikonu, s leve strane, imate količinu svetlosti, a na dnu je vreme. Bela linija je svetlost samo od zvezde, ono što astronomi zovu svetlosnom krivom. Sad, kad planeta prolazi ispred zvezde, blokira mali deo ove svetlosti, a dubina ovog tranzita odražava veličinu samog objekta. Pa uzmimo, na primer, Jupiter. Planete obično nisu veće od Jupitera. Jupiter će da uzrokuje pad u jačini svetlosti zvezde za jedan posto. Zemlja, s druge strane, manja je od Jupitera 11 puta i njen signal je jedva vidljiv u podacima.
So back to our mystery. A few years ago, Planet Hunters were sifting through data looking for transits, and they spotted a mysterious signal coming from the star KIC 8462852. The observations in May of 2009 were the first they spotted, and they started talking about this in the discussion forums.
Vratimo se našoj zagoneci. Pre nekoliko godina, Lovci na planete su pretresali podatke, tražeći tranzite i uočili su tajanstveni signal koji je stizao sa zvezde KIC 8462852. Njihove opservacije iz maja 2009. su bile prva opažanja i počeli da govore o ovome na forumima za diskusije.
They said and object like Jupiter would make a drop like this in the star's light, but they were also saying it was giant. You see, transits normally only last for a few hours, and this one lasted for almost a week.
Rakli su da bi objekat nalik Jupiteru uzrokovao ovakav pad u svetlosti zvezde, ali su takođe govorili da se radi o džinu. Vidite, tranziti obično traju svega nekoliko sati, a ovaj je trajao skoro nedelju dana.
They were also saying that it looks asymmetric, meaning that instead of the clean, U-shaped dip that we saw with Jupiter, it had this strange slope that you can see on the left side. This seemed to indicate that whatever was getting in the way and blocking the starlight was not circular like a planet. There are few more dips that happened, but for a couple of years, it was pretty quiet.
Takođe su govorili da izgleda asimetrično, u smislu da umesto jasnog pada u obliku slova U, kao kod Jupitera, imao je čudan nagib koji vidite s leva. Ovo kao da je nagoveštavalo da šta god da se preprečilo i blokira zvezdanu svetlost nije kružnog oblika poput planete. Još se nekoliko padova dogodilo, ali je nekoliko godina bilo prilično tiho.
And then in March of 2011, we see this. The star's light drops by a whole 15 percent, and this is huge compared to a planet, which would only make a one percent drop. We described this feature as both smooth and clean. It also is asymmetric, having a gradual dimming that lasts almost a week, and then it snaps right back up to normal in just a matter of days.
A onda smo u martu 2011. videli ovo. Svetlost zvezde pada za čitavih 15 procenata, a to je ogromno, u poređenju s planetom, koja bi napravila pad od svega 1%. Opisali smo ovu odliku istovremeno glatkom i jasnom. Takođe je asimetrična i postepeno se pomračuje, a to traje skoro nedelju a potom se naglo vraća u normalu za svega nekoliko dana.
And again, after this, not much happens until February of 2013. Things start to get really crazy. There is a huge complex of dips in the light curve that appear, and they last for like a hundred days, all the way up into the Kepler mission's end. These dips have variable shapes. Some are very sharp, and some are broad, and they also have variable durations. Some last just for a day or two, and some for more than a week. And there's also up and down trends within some of these dips, almost like several independent events were superimposed on top of each other. And at this time, this star drops in its brightness over 20 percent. This means that whatever is blocking its light has an area of over 1,000 times the area of our planet Earth.
A onda, nakon ovoga, nema mnogo dešavanja, sve do februara 2013. Stvari postaju zaista nenormalne. Nalazimo ogroman kompleks padova na svetlosnoj krivoj i traju oko stotinu dana, skroz do kraja Keplerove misije. Ovi padovi imaju razne oblike. Neki su veoma oštri, a neki su široki i trajanje im takođe varira. Neki traju svega dan ili dva, a neki više od nedelju dana. I takođe imamo trendove rasta i pada unutar ovih padova, skoro kao da se radi o nekoliko nezavisnih događaja nadređenih jedan drugom. A ovog puta, svetlost ove zvezde pada za preko 20 procenata. Što znači da šta god blokira svetlost, ima površinu veću za 1,000 puta od površine naše planete Zemlje.
This is truly remarkable. And so the citizen scientists, when they saw this, they notified the science team that they found something weird enough that it might be worth following up. And so when the science team looked at it, we're like, "Yeah, there's probably just something wrong with the data." But we looked really, really, really hard, and the data were good. And so what was happening had to be astrophysical, meaning that something in space was getting in the way and blocking starlight. And so at this point, we set out to learn everything we could about the star to see if we could find any clues to what was going on. And the citizen scientists who helped us in this discovery, they joined along for the ride watching science in action firsthand.
Ovo je zaista neverovatno. Pa su građani naučnici, kad su videli ovo, obavestili ekipu naučnika da su otkrili nešto prilično čudno što bi vredelo pratiti. Pa kad je ekipa naučnika to pogledala, bili smo u fazonu: "Da, mora da nešto nije u redu s podacima." Ali gledali smo veoma, veoma, veoma podrobno i podaci su bili dobri. A ono što se dešavalo je moralo da bude astrofizičkog porekla, u smislu da se nešto u svemiru preprečilo i blokira zvezdanu svetlost. Pa smo se u tom momentu zaputili da naučimo sve što smo mogli o toj zvezdi, ne bi li našli nagoveštaj toga šta se dešavalo. A građani naučnici koji su pomogli u otkrivanju ovoga, pridružili su se trci posmatrajući iz prve ruke nauku na delu.
First, somebody said, you know, what if this star was very young and it still had the cloud of material it was born from surrounding it. And then somebody else said, well, what if the star had already formed planets, and two of these planets had collided, similar to the Earth-Moon forming event. Well, both of these theories could explain part of the data, but the difficulties were that the star showed no signs of being young, and there was no glow from any of the material that was heated up by the star's light, and you would expect this if the star was young or if there was a collision and a lot of dust was produced. And so somebody else said, well, how about a huge swarm of comets that are passing by this star in a very elliptical orbit? Well, it ends up that this is actually consistent with our observations. But I agree, it does feel a little contrived. You see, it would take hundreds of comets to reproduce what we're observing. And these are only the comets that happen to pass between us and the star. And so in reality, we're talking thousands to tens of thousands of comets. But of all the bad ideas we had, this one was the best. And so we went ahead and published our findings.
Prvo je neko rekao, znate, šta ako se radi o veoma mladoj zvezdi koja još uvek ima oko sebe oblak materijala iz kojeg je nastala. A onda je neko drugi rekao, šta ako je zvezda već oformila planete, a dve od tih planeta su se sudarile, poput teorije o nastanku Zemlje i Meseca. Pa, obe ove teorije su mogle da objasne deo podataka, ali problem je bio u tome što zvezda nije pokazivala znakove mladosti i nije bilo odsjaja bilo kog drugog materijala koga zagreva svetlost zvezde, a to biste očekivali kod mlade zvezde ili kad bi se desio sudar koji bi proizveo mnogo prašine. Pa je neko drugi rekao, šta ako se radi o ogromnom jatu kometa koje prolaze pored ove zvezde krajnje eliptičnom orbitom? Pa, završilo se time što je ovo bilo zapravo u skladu s našim opservacijama. Ali slažem se da zvuči malo neprirodno. Vidite, trebalo bi vam na stotine kometa da bi stvorile ono što smo gledali. A radilo bi se samo o kometama koje slučajno prolaze između nas i zvezde. Stoga smo u principu govorili o na hiljadu do na desetine hljada kometa. Ali od svih loših ideja koje smo imali, ova je bila najbolja. Pa smo objavili naša otkrića.
Now, let me tell you, this was one of the hardest papers I ever wrote. Scientists are meant to publish results, and this situation was far from that. And so we decided to give it a catchy title, and we called it: "Where's The Flux?" I will let you work out the acronym.
Sad, dozvolite da vam kažem, da se radi o najtežem radu koji sam ikad napisala. Naučnici bi trebalo da objavljuju rezultate, a ova situacija je bila daleko od toga. Pa smo odlučili da ga naslovimo privlačno i naslovili smo ga: "Where's The Flux?" Prepustiću vam da shvatite akronim.
(Laughter)
(Smeh)
So this isn't the end of the story. Around the same time I was writing this paper, I met with a colleague of mine, Jason Wright, and he was also writing a paper on Kepler data. And he was saying that with Kepler's extreme precision, it could actually detect alien megastructures around stars, but it didn't. And then I showed him this weird data that our citizen scientists had found, and he said to me, "Aw crap, Tabby. Now I have to rewrite my paper."
No ovo nije kraj priče. Otprilike istovremeno dok sam pisala ovaj rad, srela sam se s kolegom Džejsonom Rajtom, i on je pisao rad o Keplerovim podacima. Rekao je da bi Kepler svojom izuzetnom preciznošću, vremenom zapravo otkrio vanzemaljske megastrukture blizu zvezda, ali to se nije desilo. Ja sam mu onda pokazala ove čudne podatke koje su naši građani naučnici otkrili, a on mi je rekao: "Joj, dovraga, Tabi. Sad moram da preformulišem rad."
So yes, the natural explanations were weak, and we were curious now. So we had to find a way to rule out aliens. So together, we convinced a colleague of ours who works on SETI, the Search for Extraterrestrial Intelligence, that this would be an extraordinary target to pursue. We wrote a proposal to observe the star with the world's largest radio telescope at the Green Bank Observatory.
Dakle, da, prirodna objašnjenja su bila slaba i sad smo bili znatiželjni. Pa smo morali da otkrijemo način da isključimo vanzemaljce. Pa smo zajedno ubedili našeg kolegu koji radi na SETI-ju, Potrazi za vanzemaljskom inteligencijom, da bi ovo bilo izvanredno pratiti. Poslali smo predlog da on posmatra zvezdu najvećim radio-teleskopom na svetu na opservatoriji Grin Bank.
A couple months later, news of this proposal got leaked to the press and now there are thousands of articles, over 10,000 articles, on this star alone. And if you search Google Images, this is what you'll find.
Nekoliko meseci kasnije, vesti o ponudi su procurele u štampi i imali smo na hiljade članaka, preko 10,000 članaka samo o ovoj zvezdi. A ako potražite slike na Guglu, ovo ćete da pronađete.
Now, you may be wondering, OK, Tabby, well, how do aliens actually explain this light curve? OK, well, imagine a civilization that's much more advanced than our own. In this hypothetical circumstance, this civilization would have exhausted the energy supply of their home planet, so where could they get more energy? Well, they have a host star just like we have a sun, and so if they were able to capture more energy from this star, then that would solve their energy needs. So they would go and build huge structures. These giant megastructures, like ginormous solar panels, are called Dyson spheres.
Sad, verovatno se pitate, u redu, Tabi, dobro kako su vanzemaljci objašnjenje za ovu svetlosnu krivu? U redu, zamislite civilizaciju koja je daleko naprednija od naše. U ovim hipotetičkim okolnostima, ova civilizacija je iscrpela zalihe energije svoje majke planete, pa odakle bi mogli da dobiju dodatnu energiju? Pa, imaju zvezdu domaćina, baš kao što mi imamo sunce, pa ako su bili u stanju da zarobe dodatnu energiju ove zvezde, onda bi to rešilo njihove energetske potrebe. Pa bi sagradili ogromne strukture. Ove džinovske megastrukture, poput gigantskih solarnih panela, koji se zovu sferama Dajson.
This image above are lots of artists' impressions of Dyson spheres. It's really hard to provide perspective on the vastness of these things, but you can think of it this way. The Earth-Moon distance is a quarter of a million miles. The simplest element on one of these structures is 100 times that size. They're enormous. And now imagine one of these structures in motion around a star. You can see how it would produce anomalies in the data such as uneven, unnatural looking dips.
Ovaj prizor gore je utisak koji mnogi umetnici imaju o sferama Dajson. Zaista je teško pružiti perspektivu o ogromnosti ovih stvari, no možete ovako da razmišljate o tome. Razdaljina između Zemlje i Meseca iznosi 402 000 km. Najprostiji element na jednoj od tih struktura je 100 puta veći od toga. Ogromne su. A sad zamislite jednu od tih struktura kako se kreće oko zvezde. Jasno vam je kako bi to uzrokovalo anomalije u podacima, poput nejednakih, neprirodnih padova.
But it remains that even alien megastructures cannot defy the laws of physics. You see, anything that uses a lot of energy is going to produce heat, and we don't observe this. But it could be something as simple as they're just reradiating it away in another direction, just not at Earth.
Ali stoji da čak ni vanzemaljske megastrukture ne mogu da prkose zakonima fizike. Vidite, sve što koristi mnogo energije će da proizvodi toplotu, a to ne posmatramo. Ali možda se radi o nečem prostom poput njenog preusmeravanja u drugom pravcu, samo ne u Zemlju.
Another idea that's one of my personal favorites is that we had just witnessed an interplanetary space battle and the catastrophic destruction of a planet. Now, I admit that this would produce a lot of dust that we don't observe. But if we're already invoking aliens in this explanation, then who is to say they didn't efficiently clean up all this mess for recycling purposes?
Druga ideja, koja mi je omiljena, je da smo upravo posvedočili međuplanetarnoj svemirskoj bici i katastrofalnom uništenju planete. Sad, priznajem da bi ovo proizvelo mnogo prašine koju nismo primetili. Ali kad već u svom objašnjenju prizivamo vanzemaljce, onda ko kaže da nisu efikasno počistili sav taj nered u reciklažne svrhe?
(Laughter)
(Smeh)
You can see how this quickly captures your imagination.
Vidite koliko brzo vam ovo zaokuplja maštu.
Well, there you have it. We're in a situation that could unfold to be a natural phenomenon we don't understand or an alien technology we don't understand. Personally, as a scientist, my money is on the natural explanation. But don't get me wrong, I do think it would be awesome to find aliens. Either way, there is something new and really interesting to discover.
Pa, to je to. U situaciji smo koja može da ispadne prirodni fenomen koji ne razumemo ili vanzemaljska tehnologija koju ne razumemo. Lično, kao naučnica, kladila bih se na prirodno objašnjenje. Ali, da se razumemo, bilo bi sjajno kad bismo otkrili vanzemaljce. Kako god, ima da otkrijemo nešto novo i zanimljivo.
So what happens next? We need to continue to observe this star to learn more about what's happening. But professional astronomers, like me, we have limited resources for this kind of thing, and Kepler is on to a different mission.
Pa, šta će sada da se desi? Moramo da nastavimo s posmatranjem ove zvezde kako bismo saznali šta se dešava. Ali profesionalni astronomi, poput mene, imaju ograničene resurse za ovakve stvari, a Kepler je na potpuno drugoj misiji.
And I'm happy to say that once again, citizen scientists have come in and saved the day. You see, this time, amateur astronomers with their backyard telescopes stepped up immediately and started observing this star nightly at their own facilities, and I am so excited to see what they find.
I srećna sam što mogu da kažem da su opet građani naučnici uleteli i spasili dan. Vidite, ovog puta su astronomi amateri sa teleskopima u dvorištima, prišli istog trena i počeli da posmatraju tu zvezdu po noći, u sopstvenim domovima i ja sam uzbuđena njihovim otkrićima.
What's amazing to me is that this star would have never been found by computers because we just weren't looking for something like this. And what's more exciting is that there's more data to come. There are new missions that are coming up that are observing millions more stars all over the sky.
Meni je fascinantno to da ovu zvezdu kompjuteri nikad ne bi otkrili jer prosto nismo tragali za nečim poput nje. A još je uzbudljivije da dodatni podaci tek stižu. Počinju nove misije koje će da posmatraju još milione zvezda širom neba.
And just think: What will it mean when we find another star like this? And what will it mean if we don't find another star like this?
I samo pomislite: šta će da znači kad otkrijemo još jednu ovakvu zvezdu? A šta će da znači, ako ne otkrijemo još jednu ovakvu zvezdu?
Thank you.
Hvala vam.
(Applause)
(Aplauz)