Click to Watch in HD > Science Documentary HD || Where did we come from?

Watch NEIL DEGRASSE TYSON (Astrophysicist, American Museum of Natural History): Hi, Im Neil deGrasse Tyson, your host of NOVA scienceNOW, where this season were asking six big questions. On this episode: Where did we come from? The Sun; the planets; our home, the Earth: what triggered their creation? I went on the hunt for rare evidence... Where are we? ...thats been dropping from the sky. Hes got something! RUBEN GARCIA (Meteorite Hunter): It sounds really big! NEIL DEGRASSE TYSON: And its pointing to a cosmic birth, more violent than we ever imagined. Also, life: its been around for billions of years, but how did it begin? JOHN SUTHERLAND (University of Manchester, England): You know what you want to make, but you dont have a recipe. NEIL DEGRASSE TYSON: For decades, weve been trying to cook up the building blocks of life, in the lab, and recreate the origins of it all, but the parts didnt seem to fit together, until now. JOHN SUTHERLAND: We were the guys who stood back, and looked at it in a different way. NEIL DEGRASSE TYSON: One team may have retraced a key step in the birth of life, itself. How did they do it? And what about us and our origins? They say some of the hairiest questions in human evolution could be solved by these guys. Head lice! Ew! MARK STONEKING (Max Planck Institute): Lice have been with us and evolving with us for as long as we have existed. KATIE SHEPHERD (Lice Solutions): Now, see, right there? Now come straight out. ZIYA TONG (Correspondent): Oh, my goodness. Oh, my goodness! KATIE SHEPHERD: If you want to hit the red alarm button at school, all you have to say is the word lice. NEIL DEGRASSE TYSON: These tiny bloodsuckers are rewriting human history. JEAN-JACQUES HUBLIN (Max Planck Institute): We cannot neglect the lice. NEIL DEGRASSE TYSON: Also, where does your identity come from? Your memory, of course. ANDRE FENTON (SUNY Downstate): My memories define me. NEIL DEGRASSE TYSON: This brain researcher made a major discovery about how memories are formed and even how they can be erased. ANDRE FENTON: You can wipe out who you are, and thats an alarming thing. NEIL DEGRASSE TYSON: All that and more on this episode of NOVA scienceNOW! Where did we come from? How did we get here? Our history, in the cosmos and on planet Earth, was shaped by countless events, some obviously epic, some seemingly trivial, yet all vital in getting us to this point, here and now, the people we are today. One of the reasons were here, that we exist at all, is that Earth, cosmically speaking, is in a relatively peaceful place: orbiting our Sun in a near perfect circle. Our cosmic neighborhood has granted life billions of years to evolve, mostly undisturbed. But where did this stable piece of real estate come from? Where are we? LAURENCE GARVIE (Arizona State University): Perfect place for hunting for meteorites: southern Arizona. Look at this. You couldnt ask for a better place. Its open desert. Its an old lakebed, and so the sand has been blown away, like right now, and its exposing the rocks that are on the ground. And youre just looking for something that looks a little bit different. And youll know it when you see it. NEIL DEGRASSE TYSON: Well, Im from the city. So all this looks different. Ill be hauling everything back for you. So how do you spot a meteorite? Well, sometimes, the signs are hard to miss. Some leave deep impacts in Earth, like one that blasted Arizonas Barringer Crater, 50,000 years ago. But most leave less obvious traces. They can be as small as dice, reduced to a rocky cinder. Then they have to be distinguished from Earths rocks. One trait stands out in nearly all meteorites: metal; theyve got it. So, the best way to find a meteorite is to hear it first. No question about that one. RUBEN GARCIA: And we can pick that up, this far out. NEIL DEGRASSE TYSON: Ruben Garcia brought along some samples and showed me why a metal detector is the meteorite hunters best friend. RUBEN GARCIA: Its what meteorite hunters call a halo. You dont have to swing over the meteorite. You get in that halo area and you hear the sound going up. NEIL DEGRASSE TYSON: You get in the zone. RUBEN GARCIA: We like that.

Youtube Channel / HD-channel