字幕列表 影片播放 列印英文字幕 A group of scientists is saying that the asteroid impact that killed off the dinosaurs might've changed the world far more than we realized! Some 66 million years ago, a 10-kilometer-wide asteroid hit the Yucatan Peninsula and the global effects killed more than three-quarters of all species, including dinosaurs and many ocean-dwelling life forms. The immediate aftermath was earthquakes, tsunamis, and volcanic eruptions, as well as vaporized rock launched high above the surface that heated as it fell back to Earth, sparking fires. And these fires are what changed the climate and decimated most living things! According to this new model: Soot from the global wildfires was heated by the Sun and lofted high into the atmosphere. There, it created an impenetrable barrier around the globe. Just picture it… The planet is as dark as a moonlit night in the middle of the day, meaning little to no photosynthesis. Any plants not killed by wildfires are dead. The the lynchpin of the ocean food chain -- phytoplankton -- is gone. All the species that rely on these for food are dead. The atmospheric soot causes global surface temperatures to drop by as much as 28 Celsius over land and 11 over the oceans. But the soot in the atmosphere keeps absorbing sunlight, heating the stratosphere, sucking up water vapour, and destroying the ozone. Eventually the atmosphere is cleared of soot, but only after a year of darkness, and then the environment is decimated. This is not a planet to call home. Amazingly, this model shows it doesn't take a lot of soot for this kind of global devastation to happen. One simulation used just 5 billion tons of soot, about a third of what scientists think was actually produced after the impact. But this simulation isn't exact to how the world was 66 million years ago. Still, it's a sobering thought. While nuclear warfare or a smaller impact wouldn't have the same effects, either would still put enough soot into the atmosphere to cool the surface and heat the upper atmosphere, potentially changing the global climate enough to wipe out multiple species. Speaking of wiping out species like dinosaurs, what colour were dinosaurs really? We dug into it in this episode right here. Let us know what other interesting science questions you'd like us to answer in the comments, be sure to like this video, and subscribe for more Seeker.
B2 中高級 美國腔 关于可能杀死恐龙的另一种理论(An Alternative Theory About What Could Have Killed The Dinosaurs) 13 2 joey joey 發佈於 2021 年 04 月 17 日 更多分享 分享 收藏 回報 影片單字