今天是黑洞星期五！
What is a black hole? A black hole is an astronomical object with a gravitational pull so strong that nothing, not even light, can escape it. A black hole’s “surface,” called its event horizon, defines the boundary where the velocity needed to escape exceeds the speed of light, which is the speed limit of the cosmos. Matter and radiation fall in, but they can’t get out.
Two main classes of black holes have been extensively observed. Stellar-mass black holes with three to dozens of times the Sun’s mass are spread throughout our Milky Way galaxy, while supermassive monsters weighing 100,000 to billions of solar masses are found in the centers of most big galaxies, ours included.
This image is an artist’s concept of a tidal disruption event that happens when a star passes fatally close to a supermassive black hole, which reacts by launching a relativistic jet.
What is a black hole? Learn more.
Black Hole’s Dust Ring May Be Casting Shadows From Heart of a Galaxy.
Image Credit: Sophia Dagnello, NRAO/AUI/NSF
什么是黑洞？黑洞是一个具有强大引力的天文物体，任何物体，甚至光，都无法逃脱它。黑洞的“表面”，称为视界，定义了逃逸速度超过光速的边界，光速是宇宙的速度极限。物质和辐射进入，但它们出不去。
人们已经广泛地观察到了两类主要的黑洞。质量为太阳三到几十倍的恒星质量黑洞遍布我们的银河系，而在大多数大星系(包括我们的星系)的中心发现了质量为太阳10万到10亿倍的超大质量黑洞。
这幅图片是一个艺术家对潮汐中断事件的概念，当一颗恒星致命地靠近一个超大质量黑洞时，这个黑洞会通过发射相对论性喷流做出反应。
什么是黑洞？了解更多。
图片来源：Sophia Dagnello，NRAO/AUI/NSF