字幕列表 影片播放 列印英文字幕 65 million years ago, an asteroid taller than Mount Everest hit the Gulf of Mexico near the current location of the small Mexican town of Chicks. A Lube 10 kilometer wide rock struck the sea at 110,000 kilometers per hour, with the force of more than a 1,000,000,000 Hiroshima bombs. The blasts and fire and rock kilometers high the heat from the impact vaporized the water beneath the surface. The rock melted, leaving a molten layer three kilometers deep. The crater was 180 kilometers wide on 10 kilometers deep, more than twice the size of the island of Hawaii. Scientists believe this event wiped out the dinosaurs. The asteroid was millions of times smaller than the Earth, and yet it had enough power to cripple the planet. A team at NASA's Ames Laboratory in California searches for clues. Peter Schultz is the authority on asteroid impacts. Asteroids have changed the earth. They changed the life on their chicks. Move impact was not that rare an event so it's critically important to understand what happened then, just to be able, understand what might happen in the future. A custom built gun will simulate an asteroid strike today. We want to do some experiments with this Massa and broke a gun That was a really big gun. Uses gunpowder Ha jin gas and send the projectile down through this long tomb through one of these ports. Then goes into the chamber and slams into the target, and it launches a projectile at very high speeds. In this case, we're gonna go up to around five kilometers per second. Peter has dedicated his life's work to understanding impact craters, slamming into things and blowing them up. I mean, every kid will want this. I used to play in a sandbox of third grade still doing it. A small ball of aluminium will fired over 20,000 kilometers an hour into this sand bed. A model for the earth. We want to watch. What happens then? We get to understand, ma'am happened 65 million years ago. You're clear right now. Okay? Lock and load. High voltage is good. Oh, gorgeous. There's this big giant prune because trade up and this plume he's heading straight out into outer space. This kind of impact shoots the blast materials straight up into after space, out of harm's way. for vertical impact. A lot of the energy occurs locally, sending it help that disappears. Most of them checked land right in that region, but some dinosaurs were thousands of kilometers away. How could an impact like this affect them? I don't think this is what happened to six. Peter believes the impact site holds vital clues hidden beneath the Gulf of Mexico. Today lies the chicks. A look crater, most small craters, a circular. But the chicks love Crater is giant, and its inner rim is shaped like an egg under its skin. There's a layer of lighter colored debris and shattered rock fallout from the impact. It's far deeper on one side of the crater, suggesting the asteroid struck the Earth in an unusual way. Peter believes that the asteroid hit not head on, but a shallow angle to the earth. We'll see what happens, becoming a low angle. We're going to be coming out of here, Really. The vapor plume now isn't just simply going up and out. It's actually going down. Range is kind of like having a nuclear explosion moving along across the surface. Expanding the low angle impact produces a different kind of crater It's egg shaped, just like the crater, a chick salute that's much more serious than a vertical impact for life on Earth. It would have meant that there was a zone of death and destruction. Asteroids can bring a lot of pain to the earth. Big wins can weigh. Know that the dinosaurs were wiped out by a giant impact, and giant impacts might have caused other mass extinctions in the past. A CZ Well, how many times Earth has been hit is unclear. There's little sign of our planet's turbulent past. You can't see the crater from every asteroid that's ever hit the earth. The reason why is because the Earth has active geology and weathering, so most craters have been wiped away. Volcanic eruptions, earthquakes and flowing water have a raised most of the evidence, but of record of past imp, actors does exist on our nearest neighbor. The moon Moon has no atmosphere, has no running water, has no weather, and so it is preserved a record of everything that's hit it or the age of the solar system. By looking at the moon, scientists can estimate how many asteroids hit the Earth, NASA's lunar orbiters of photographed of a 98% of the moon's surface in high resolution, the images reveal an extraordinary story over 80,000 impact craters. There is no question, but that at some point in the future and asteroid will strike the Earth with enough energy to extinguish most life on Earth. If not all asteroids are civilization killers. So knowing about asteroids is, in my mind one of the most important responsibilities that we, as a species, have not stepped up to yet.