Scientists close to first sighting of black hole in the Milky Way
Astronomers attempting to capture the first images of the black hole at the heart of the Milky Way have given early hints that the ambitious project has been successful.
The observations, by the Event Horizon Telescope, are expected to be unveiled in the spring in one of the most eagerly awaited scientific announcements of 2019. Now, a senior scientist on the project has said “spectacular” data was gathered during observations of two black holes, including Sagittarius A* at the centre of our own galaxy.
“We managed to get very high-quality data at the very high resolutions necessary to observe the [black hole’s] shadow, if it’s really there,” said Sera Markoff, a professor of theoretical astrophysics and astroparticle physics at the University of Amsterdam, who co-leads the EHT’s Multiwavelength Working Group.
The team is in the final phase of reviewing data that was gathered in 2017 and Markoff could not confirm yet whether the observations had produced the first direct image of a black hole’s silhouette.
Prof Peter Galison, who is based at the department of the history of science at Harvard University and is also involved in the project, said that, if successful, the EHT’s first image would become one of the most significant in the past 50 years of astronomy. “If we get an image out of it, it will become one of the iconic images of science,” he said. “It’s an extraordinarily ambitious project.” There is little doubt about the existence of black holes: the phenomenally dense objects distort the fabric of space-time in their vicinity, causing objects and light to appear to swerve off course. More recently, the gravitational wave observatory Ligo has detected ripples sent out across space-time when pairs of black holes collide.
Until now, though, a black hole has never been directly observed. The main barrier is that black holes are so compact that a telescope roughly the size of Earth would be required to see even the nearest one.
The EHT gets around this by linking together 15-20 telescopes spanning the South Pole, Europe, South America, Africa, North America and Australia.
Collectively, the array has a resolution equivalent to being able to see a drawing pin in New York from London.
The EHT uses a technique known as interferometry, in which astronomers at observatories on different continents simultaneously observe the same object, then combine the collected data on a supercomputer.
This requires all the telescopes in the array to swivel towards the target black hole and measure every radio wave coming from its direction. Coordinating this was a “huge accomplishment of diplomacy andorganisation”, according to Galison.
The EHT has two primary targets: Sagittarius A*, at the centre of the Milky Way, and a super massive black hole called M87 in the Virgocluster of galaxies. M87 is about 50m-60m light years away, but at more than six billion solar masses (1,000 times larger than our local black hole), astronomers hope it should be visible.
No one is sure what the image will look like but theoretical predictions show a black silhouette, set against a surrounding glow of radiation, something like the depiction in the film Interstellar. “You’d imagine seeing a black shadow or depression,”said Markoff.
Besides telling us what black holes look like, the EHT could also reveal whether they have properties predicted by Einstein’s theory of general relativity and give insights into exotic processes that occur in the extreme environment close to the event horizon.
Detailed observations will also be made of dramatic jets of material that are thrown out from some black holes, including M87. It is not clear whether Sagittarius A*, a relatively small black hole, has jets – it is possible that they are too feeble to have been spotted previously – and the EHTcould resolve this question.
“We see these enormous jets of plasma moving almost at the speed of light,” said Markoff. “They can be hundreds of millions of times the size of the black hole itself – bigger than the galaxy.”
Black hole jets are believed to play a major role in cosmology, contributing to the formation of the cosmic web, in which galaxies are strung in clusters across the universe.
1.According to the passage, what are primary targets of EHT? A.Sagittarius and Neptune. B.Sagittarius A* and M87. C.The Milky Way.
D.Unidentified Flying Object.
2.What can EHT do besides telling us what black holes look like ?
A. Revealing if they have properties predicted by Einstein’s general relativity theory.
B. Measuring radio wave coming from black hole.
C. Causing objects and light to appear to swerve off course. D. Combining the collected data on a supercomputer..
3.What is the main barrier that prevent us from directly observing the black hole ?
A. They are too feeble to have been spotted previously.
B. These enormous jets of plasma are moving at the speed of light.
C. Black holes are so compact and we need a telescope roughly the size of Earth.
D. They are about 50m-60m light years away. 4.Which of the following description of Sagittarius A* is incorrect ?
A . Sagittarius A* is at the centre of the Milky Way. B. Sagittarius A* is about 50m-60m light years away. C. It is not clear whether Sagittarius A*has jets. D. Sagittarius A* is a relatively small black hole. 5. Which of the the following conclusion is correct according to the passage?
A. The first direct image of a black hole’s silhouette is confirmed. B.15-20 telescopes are roughly the size of Earth.
C. Black hole called M87 is much bigger than Sagittarius A*.
D. The image of a black hole is used as depiction in the film Interstellar.
导读：文章选自《卫报》https://www.theguardian.com/science/2019/jan/11/scientists-close-to-capturing-first-image-of-black-hole-at-the-centre-of-the-milky-way 【文章大意】
本文主要介绍天文学家对黑洞的研究。天文学家试图捕捉到银河系中心黑洞的第一张照片，由“事件地平线”望远镜进行的观测，预计将在今年春天公布。人类以前从未直接观察到黑洞。EHT（“事件地平线”望远镜）通过连接横跨南极、欧洲、南美、非洲、北美和澳大利亚的15-20个望远镜来解决这个问题，并且将对从一些黑洞（包括M87）中抛出的物质的剧烈喷射进行详细观察。
【词汇】
astronomers n.天文学者，天文学家( astronomer的名词复数) unveil v.揭露;揭去…的面罩;拉开…的帷幔;使公之于众 silhouette n. 轮廓，剪影;（人的）体形;（事物的）形状 phenomenally adv. 现象上地，明白地 collide v. 碰撞;相撞;冲突;抵触 barrier n. 屏障;障碍;栅栏;分界线 interferometry n.干涉测量（法）
feeble adj.虚弱的，衰弱的;无效的，无意的;缺乏决心的，缺乏活力的 cosmology n.宇宙学
短语精选：
theoretical astrophysics理论天体物理学 in the past 在过去; 以往; 平昔;往昔 more recently 最近以来 off course不在规定的过程中
appear to似乎，好像 equivalent to等于，折合
according to根据，按照; 据…所说;如; 比照
set against靠着…; 把…与…相比;与…抗衡; 在…映衬下 hundreds of millions亿万; 亿万的
【参考答案及解析】
1.【B】细节题。由本文段落中提到的“TheEHT has two primary targets: Sagittarius A*, at the centre of the Milky Way,and a supermassive black hole called M87 in the Virgo cluster of galaxies.”中可以很容易得出答案。
2.【A】细节题。根据文章内容“Besides telling us what black holes look like, the EHTcould also reveal whether they have properties predicted by Einstein’s theoryof general relativity .”，可以得出只有B项是正确的。
3.【C】细节题。根据文章中提到的“Until now, though, a black hole has never been directlyobserved. The main barrier is that black holes are so compact that a telescoperoughly the size of Earth would be required to see even the nearest one.”，其他几个选项虽然是原文，但并不是题目中的原因。
4.【B】分析题。需要通读全文后，按照文中对Sagittarius A*的介绍和解释一一排除，最后可以发现B项说的并不是Sagittarius A*。
5【C】整理归纳题。这四个选项分别对文中不同的段落做出了内容小结，很容易判断错，需要自己对原文进行深度阅读和理解才能答对。尤其是正确答案C，并没有直接在文中给出，而是需要考生自己做出判断。
【参考译文】
科学家们接近首次观测到银河系中的黑洞
天文学家试图捕捉到银河系中心黑洞的第一张照片，这一雄心勃勃的计划已经取得了成功。
这项由“事件地平线”望远镜进行的观测，预计将在今年春天公布，这是2019年最受期待的科学声明之一。现在，该项目的一位资深科学家说，在观察两个黑洞的过程中，包括我们银河系中心的人马座A*都收集了“惊人”的数据。
阿姆斯特丹大学理论天体物理学和天体粒子物理学教授塞拉·马尔科夫（Sera Markoff）说：“我们设法以非常高的分辨率获得了观察黑洞阴影所需的高质量数据，如果真的存在的话。”
该小组正在审查2017年收集的数据的最后阶段，马尔科夫还不能确认观测结果是否描绘了黑洞轮廓的第一个直接图像。
哈佛大学科学史系的彼得·加利森教授也参与了这个项目，他说，如果成功的话，eht的第一个图像将成为过去50年天文学中最重要的图像之一。他说：“如果我们从中得到一个图像，它将成为科学的标志性图像之一。”“这是一个非常雄心勃勃的项目。” 毫无疑问，黑洞的确存在：密度惊人的物体扭曲了其附近的时空结构，导致物体和光线似乎偏离了轨道。最近，引力波天文台LIGO探测到，当两对黑洞碰撞时，时空会发生扩散。
然而，直到现在，人类还从未直接观察到黑洞。主要的原因是黑洞是如此的紧凑，以至于需要一个与地球差不多大小的望远镜才能看到最近的黑洞。
EHT通过连接横跨南极、欧洲、南美、非洲、北美和澳大利亚的15-20个望远镜来解决这个问题。总的来说，这种望远镜组队形成的分辨率相当于能够从伦敦看到纽约的图钉。
EHT使用了一种称为干涉测量的技术，在这种技术中，不同大陆的天文学家同时观测同一物体，然后将收集到的数据合并到一台超级计算机上。
这就要求小组中的所有望远镜都能朝着目标黑洞旋转，并测量来自其方向的每一个无线电波。根据加利森的说法，协调这项工作是“外交和组织方面的巨大成就”。 EHT有两个主要目标：位于银河系中心的人马座A*和位于处女座星系团中名为M87的超大质量黑洞。M87距离我们约5000-60米光年，但是超过60亿个太阳质量（比我们当地的黑洞大1000倍）下，天文学家希望可以观察到它。
没人知道这幅图像会是什么样子，但是理论预测显示，在周围辐射光的衬托下，有一个黑色的轮廓，类似于电影《星际穿越》中的描绘。“你可以想象看到黑影或洼地，”马尔科夫说。
除了告诉我们黑洞是什么样子外，eht还可以揭示黑洞是否具有爱因斯坦广义相对论所预言的性质，并洞察发生在接近事件视界的极端环境中的奇异过程。
此外，还将对从一些黑洞（包括M87）中抛出的物质的剧烈喷射进行详细观察。目前还不清楚相对较小的黑洞人马座A*是否有喷流——很可能是因为它们太弱了，无法在以前被发现——现在eht可以解决这个问题。
“我们看到这些巨大的等离子体喷流几乎以光速运动，”马尔科夫说。“它们可能是黑洞本身大小的数亿倍——比星系还要大。”
黑洞喷流被认为在宇宙学中起着重要作用，有助于形成宇宙网，在这个网中，星系在宇宙中以星团的形式排列。
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