黑洞照片怎么拍的？
The picture shows a halo of dust and gas, tracing the outline of a colossal black hole, at the heart of the Messier 87 galaxy, 55m light years from Earth.
What are black holes?
Black holes were first predicted by Einstein’s theory of general relativity, which reimagined gravity as the warping of space and time by matter and energy.
The equations predicted that, beyond a certain threshold, when too much matter or energy is concentrated in one place, space and time collapse, leaving behind a sinkhole through which light and matter can enter but not escape.
At first these were thought to be mathematical oddities, rather than real astronomical objects, but in the past century overwhelming evidence has confirmed that black holes are out there.
The edge of the black hole is defined by its so-called event horizon. This is the point at which escaping would require something to travel at faster than the speed of light – which as far as we know nothing does – so it is the point of no return.
Black holes are surrounded by an accretion disk of dust and gas, orbiting at close to the speed of light. A lot of this material is destined for oblivion, although some of it is ejected as powerful jets of radiation.
什么是黑洞?
聽霍金講述黑洞~
首張黑洞照片揭曉，人類第一次看到黑洞的視界面!它由有效口徑相當于地球直徑的望遠鏡陣列觀測到，經過2年“沖洗”完成。
北京時間4月10日21點整，天文學家召開全球新聞發(fā)布會，宣布首次直接拍攝到黑洞的照片。這張照片來之不易，為了得到這張照片，天文學家動用了遍布全球的8個毫米/亞毫米波射電望遠鏡，組成了一個所謂的“事件視界望遠鏡”(Event Horizon Telescope，縮寫EHT)。
這顆黑洞位于代號為M87的星系當中，距離地球5300萬光年之遙，質量相當于60億顆太陽。
大家在平時閱讀科學新聞、科普書籍以及觀看科幻電影的時候，也經常能看到黑洞的樣子，但其實都是根據科學理論推測出來的，并非直接觀測。2014年，由諾蘭執(zhí)導的科幻電影《星際穿越》大熱，在這部影片中，光環(huán)籠罩下的超大質量黑洞——“卡岡圖亞“(Gargantua)令人心生敬畏，這里的黑洞形象是使用計算機模擬出來的。在著名理論物理學家吉普·索恩的指導下，這里的模擬已經非常接近真實了，但畢竟還是模擬，這次是玩真的了。
為什么能給不發(fā)光的黑洞拍照?
這些年，黑洞這個名詞頻頻出現在媒體報道中，想必很多人都已經對它有些了解。恒星級質量的黑洞是由大質量恒星演化到末期核心發(fā)生引力坍縮而成。中等質量黑洞和大質量黑洞的形成的具體方式目前還沒有定論：可能是由小黑洞合并形成，也可能是由黑洞通過吞噬物質逐漸形成，還可能是由大量氣體物質直接坍縮形成。
黑洞給人印象最深刻的印象就是吞噬一切，甚至光線。如果是孤零零的黑洞，我們真的是沒辦法采用電磁波手段進行拍攝了。
