黑洞里面是什么？！

黑洞里面是什么？！ Thanks to German astronomers, we now have the most accurate measurements yet of the giant black hole that sits at the centre of our galaxy. And what a beast it is: as wide as Earth's orbit around the sun and 4.3 million times more massive than our home star. Lucky, then, that it is 27,000 light years away. Researchers from the Max Planck Institute for Extraterrestrial Physics used two telescopes operated by the European Southern Observatory in Chile to watch stars as they circled the centre of the Milky Way. The 16-year study, now published in the Astrophysical Journal, has proved beyond doubt that lurking at the very centre of the galaxy is a black hole. Black holes are clearly intriguing, and not just to scientists. Earlier today, a colleague known more for his in-depth investigations into the wrongdoings of governments and multinationals than his knowledge of quantum gravity, asked what seems like a simple question: "What's inside a black hole?" Sensing my attempt at an answer wasn't good enough, I called Stefan Gillessen, one of the authors of the latest study, for an explanation. To begin with, he pointed out that scientists should only ask questions that can be answered, and since it is impossible to get information out of a black hole (in the form of light, for example) we can never really know. But let's not give up just yet. Black holes are created when large stars explode and collapse in on themselves. Many will have masses similar to our own sun, but others grow to much larger masses. Theoretical physicists have thought long and hard about what goes on inside black holes and their conclusions are mind-bending to say the least. Despite the fact that they suck in material from anything and everything that strays too close, they are empty. The mass of a black hole is confined to an infinitely small point at its centre, called a singularity. How much blackness surrounds a singularity – in effect, the size of the black hole – is defined by the strength of its gravitational pull. Far away from a black hole, light can zip around as usual, lighting up the heavens as it goes. But closer to a black hole, gravity becomes stronger and stronger until eventually, not even light can move fast enough to escape its pull. This is why a singularity is surrounded by a vast sphere of darkness. The point at which the hole's gravity becomes strong enough to prevent light escaping is known as the event horizon. "To know what's inside a black hole, we need something to come out from behind the event horizon, and reach us via a telescope. The easiest thing for astronomers would be light, but a black hole is so massive not even light can escape so no information can get out," he said. "You could go and look, but once you're in you never come back out again." Gillessen admits to feeling uncomfortable about the concept of singularities, but the late John Wheeler, who coined the term "black hole" in 1967, put it nicely in his 1999 autobiography, "Geons, Black Holes and Quantum Foam: A Life in Physics". He said black holes teach us that "space can be crumpled like a piece of paper into an infinitesimal dot, that time can be extinguished like a blown out flame, and that the laws of physics that we regard as sacred, as immutable, are anything but." 感谢德国天文学家，我们现在知道了躺在我们银河系中心的那个黑洞的精确尺寸。 简直是个巨兽啊～宽度相当于地球公转轨道的直径，质量比我们的太阳还大430万倍。不过幸好，它离我们有2万7千光年那么远。 来自马克斯?普朗克地外物理研究所的科学家们，用设在智利的欧洲南部天文台观察那些环绕银河系中心运行的行星。16年的研究成果毫无疑问的证实——潜藏在我们银河系中心的是一个巨大的黑洞，这些成果现已发布在《天体物理学杂志》。 黑洞让人感到疑惑，这不仅仅是对科学家来说。我有一位同事，他喜欢深入研究那些政府以及跨国公司的黑幕，对那些糗事了解的要比量子引力多多了，今天早些时候，他问我这样一个问题，“黑洞里面是什么,”我意识到自己没法很好的回答这个问题，所以我打电话给Stefan Gillessen寻求解答，他是上面那个最新成果的研究者之一。 一开始，他就告诉我，科学家只应该问能够回答的问题，既然我们不可能从黑洞中获取信息(例如，以可见的方式)，那么我们永远不能确切知晓那里面究竟是什么,不过，我们当然不能就此放弃。 黑洞是由于大型天体爆炸并自我坍缩而形成的。其中的一些和我们太阳的质量差不多，而另一些则要大很多。 理论物理学家已经对黑洞内究竟发生了什么探索良久，然而他们的结论可以说实在令人费解。尽管黑洞吞噬所有的物质并且将其碾作一团，它仍然是空空如也。黑洞所有的质量都处于其中心一个无穷的小点上，我们叫它“奇点”。 事实上，奇点周围有多大一块黑暗区域，也就是黑洞的尺寸，是由它所产生的引力大小来衡量的。离黑洞很远的时候，光可以像往常那样自由穿梭，照亮它途径的天空。而靠近黑洞后，引力变得越来越大，最终，即使跑的像光那样快也无法逃离黑洞的引力。这就是为什么奇点四周有那么大一块黑暗区域。那个由于引力巨大以至光线也无法逃脱的边界，我们叫它“视界”。 “要知道黑洞里究竟是什么，我们需要有什么东西从视界里出来，并让我们用望远镜看到。对天文学家来说，要找到这样一个东西，最简单的话就是光，不过黑洞质量太大了连光都逃不了，因而我们无法获得任何信息”他说，“你可以去黑洞看看，不过一旦你进去就再也回不来了。” Gillessen承认他对奇点的概念感到不自在。但已故的约翰?惠勒，也就是于1967年创造“黑洞”这个词的人，把这个词恰如其分地写在了他1999年自传的封面上，书名叫《真子、黑洞和量子泡沫:在物理学的一生》("Geons, Black Holes and Quantum Foam: A Life in Physics")。惠勒说，黑洞告诉我们，“空间可以像一张纸那样坍缩至一个无限小的点，时间也可以像吹熄火苗那样湮灭，而那些不可侵犯的、亘古不变的物理定律，也可以荡然无存。”