字幕列表 影片播放 列印英文字幕 Life goals: meet an alien or at least answer the question; are we alone in the universe? What I’m saying is WHERE ARE ALL THE ALIENS? Hey guys, Julia here for DNews Probability tells us that our galaxy should be teeming with life. Our universe is about 14 billion years old. Our Solar System and our Earth are only 4.5 billion years old. But the universe is a big place, and there are plenty of other solar systems that are wayyy older even in our own galaxy. So intelligent life should have evolved millions of years sooner than we did and they should have taken over the galaxy by now. At that rate, we should have some evidence that the truth, or life, is out there. So what’s the deal with the radio silence? This is the very question physicist Enrico Fermi asked in the 1950s, specifically “Where is everybody?”. This idea that alien life should be out there, but we haven’t heard anything is called the Fermi Paradox. Most solutions to the paradox can be broken down into two broad categories, aliens don’t exist, or they do exist. If aliens don’t exist, it might be because a planet that can sustain life is rare, and that complex life-- such as plants and animals-- would evolve is even RARER. This is creatively called the Rare Earth Hypothesis, which suggests that we are actually alone. Another idea is that an intelligent, colonizing, intergalactic lifeform is incredibly rare. Robin Dale Hanson, an associate professor of economics at George Mason University, described this idea as ‘The Great Filter’. He suggests that each stage of evolution might just be really hard to reach. For aliens evolve and become visible to us, they would need the right star system, reproductive molecules like RNA, simple life, complex life, sexual reproduction, multicellular life, tool using life, where we are now, and last but not least, colonization explosion, or the ability to take over the galaxy. He suggests each of these steps is very improbable, let alone all of them. And one or more of these steps is “the Great Filter”, meaning that it’s so incredibly difficult to pass, that nothing in the universe has done it. Since we’ve already made it through most of these steps, it stands to reason that the biggest hurdle of “The Great Filter” might be where we are now or where we nearly are. If that’s the case, that means we are approaching the filter.. and odds are, we will destroy ourselves before we become interstellar, just like everyone else in the universe probably did. But okay what if aliens DO exist? Where are they? One hypothesis supported by Author Michael Michaud is that aliens are just shutting the hell up. And for good reason, self protection. The universe could be a giant hostile place filled with warfaring colonizing civilizations. So by staying at home and staying quiet, they aren’t drawing attention to themselves to keep themselves safe. But some people think extraterrestrial life is here. And that maybe they just don’t care. Maybe they don’t find us interesting enough. Or maybe they’re nice aliens, who care about us a whole lot. So much so that they won’t even touch us. One theory published in the journal Icarus in 1973 suggests that we are part of some sort of protected zone, almost like a preserve or a zoo! But maybe they ARE here and reaching out to us. But we just can’t communicate with them, maybe we’re just bad at reading the signs. Maybe they communicate with technologies that are different from radio waves, like lasers, or something we haven’t even conceived yet! There’s so many more solutions to the Fermi paradox, one physicist Stephen Webb lists at least 50 solutions in his book “If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?”. But he actually believes we are alone. No matter what, I want to believe we’re not alone. But perhaps the universe is too vast for us to ever know. While we haven’t heard anything from other civilizations that doesn’t mean we’ll stop scanning the skies anytime soon. In fact, NASA’s got a new telescope in the works that will see further than we’ve ever seen before. If you want an incredible behind-the-scenes look at the new James Webb Space Telescope, make sure to check out Discovery’s brand new documentary Telescope! The world premiere is this Saturday, February 20 at 9pm on the Discovery Channel. We’ll be watching too! So what do you think? Do you think life is out there? Or what’s your favorite solution to the paradox? Let us know down in the comments below
B2 中高級 美國腔 為什麼外星人還沒有發現我們? (Why Haven't Aliens Found Us Yet?) 130 17 林奉毅 發佈於 2021 年 01 月 14 日 更多分享 分享 收藏 回報 影片單字