NASAさんのインスタグラム写真 - (NASAInstagram)「What are black holes, and could they suck up my house? 😱 Let’s kick off our first Saturday Science by exploring these fascinating objects! To understand black holes, first let’s talk about gravity. Gravity is a force that pulls objects toward each other, and objects with more mass pull harder. For example, the planets of our solar system orbit the Sun because it has much more mass than they do. Black holes are astronomical objects with such strong gravity that even light can’t escape, which is why they look black! They contain lots of mass that is very tightly packed. For example, if the period at the end of this sentence were a black hole, it would have as much mass as Jupiter’s biggest moon, Ganymede. Dust, gas, and stars can get pulled into black holes, forming glowing rings or brilliant jets we can see from far away. That’s partly how we find black holes - the matter around them, and how they affect space, provide clues to where they are even though we can’t see them with our eyes. The good news: For things to get pulled in by a black hole, they need to get much closer than Earth will ever get. And even though some black holes form from collapsing stars, those stars are much bigger than our Sun, so it won’t happen in our solar system. Your house should be safe from falling into a black hole. NASA uses telescopes on the ground and in space to study black holes, and we’re excited to learn all we can about these fascinating objects. To explore more, check out the link in our bio for activities, videos and coloring pages!」6月11日 0時30分