字幕表 動画を再生する 英語字幕をプリント Hey there and welcome to Life Noggin. Black holes are some of the strangest places in the universe. They are points in space where the gravity is so strong, nothing can escape their pull. Most black holes are created when a dying star runs out of fuel. If the star is large enough, it starts to collapse in on itself. As its matter is compressed, it becomes so tightly packed into such a small space that its gravitational force becomes huge -- and I mean really huge. Black holes can pull in planets, stars... even light can't escape their grasp. The Milky Way alone contains up to a billion of these so-called stellar black holes -- stellar, because they are formed by collapsing stars, and also, I assume, because they're awesome. They range in mass but are formed from a star that are at least 3 times as massive as our sun. And it's the mass that counts, not the size. If a star the mass of Earth became a black hole, it would end up being only the size of a marble! Imagine holding the entire mass of the earth in the palm of your hand. Of course, you couldn't really do that because the extreme gravitational pull would destroy you...along with your house, your neighborhood, and the entire planet. Let's move on. But there is something even larger than a stellar black hole. Supermassive black holes can be millions or even billions of times as massive as our sun. They can result from stars crashing into each other or smaller black holes merging together. Astronomers think it's likely that every galaxy has a supermassive black hole at its center -- even the Milky Way. So, should we be worried that we'll suddenly be sucked into a black hole and torn apart? Well, we're ok for now. The closest supermassive black hole to us, Sagittarius A, is 26,000 light years away. And you can't be pulled in unless you get really close to one. For example, if our sun were to somehow become a black hole, it would still have the same mass, just condensed, and Earth would continue orbiting it like normal. Of course, we'd probably miss the solar radiation. But what if we did encounter a black hole? What happens inside of one? Every black hole contains an event horizon, the point of no return, after which nothing can escape. Inside of this is the singularity -- the place where the star has collapsed down until it has zero volume and infinite density. Since everything past the event horizon disappears, it's really hard for us to know what's going on in the singularity. Maybe it's a huge party being thrown, and I wasn't invited. In fact, because black holes don't emit anything on their own, we've never actually seen one. We only know about them because of how they affect the matter around them. When the gases and dust of nearby galaxies get pulled into the event horizon, the atoms gain energy and heat up. This causes them to emit radiation that we can read here on Earth. Using this radiation, astronomers have a plan to create the first-ever image of a black hole! This isn't the kind of picture you'd snap on your phone and share on Instagram. Instead, 12 teams around the world will set up radio telescopes calibrated to the same frequency -- 230 gigahertz -- all pointed at our supermassive black hole neighbor, Sagittarius A* Their data will be pieced together as if it came from one giant, earth-sized radio telescope. If it works correctly, researchers think that we'll be able to see the ring of radiation around Sagittarius A*. So, although we won't technically “see” the black hole itself, we'll essentially be able to see its outline and the dark shadow that the black hole casts on the radiation. This experiment could help us finally confirm that black holes do exist. It could also be used to study how black holes change over time, how their magnetic fields work, and even how they destroy materials. It's going to take quite a few months to get the data processed, so look for results in 2018. But when it's done, good old Sagittarius A* will be the “star” of the show. I hope it's ready for its close up. Interesting question here, so, what would you most want to take a picture of in space? A black hole? A distant planet? Let me know in the comments below!
B1 中級 米 地球はブラックホールに吸い込まれるのか? (Will Earth Ever Be Sucked Into A Black Hole?) 31 0 Jerry Liu に公開 2021 年 01 月 14 日 シェア シェア 保存 報告 動画の中の単語