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VOA科学技术2022--科学家发现离地球最近的黑洞

时间：2022-11-17 02:23:32

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Scientists Discover Closest Black Hole to Earth

Scientists say they have discovered the closest black hole to Earth.

Black holes are areas in space where gravity is so strong that nothing – not even light – can escape them. They are believed to be formed from collapsed2 stars.

An international group of astronomers3 recently announced the discovery of the black hole, which sits about 1,600 light years from Earth. A light year is the distance light travels in one year. In space, light moves about 9.4 trillion kilometers each year.

The researchers named the black hole Gaia BH1. They say it sits in the constellation4 of Ophiuchus. A constellation is a grouping of stars. The black hole is believed to weigh about 10 times the mass of our sun. The team said it is three times closer to Earth than the previous record-holder.

The newly discovered gravitational mass was identified by observing the motion of its orbiting star. The star orbits the black hole at about the same distance as Earth orbits the sun.

Kareem El-Badry is an astrophysicist with the Harvard-Smithsonian Center for Astrophysics and Germany's Max Planck Institute for Astronomy. He was the lead writer of a study describing the discovery in Monthly Notices of the Royal Astronomical5 Society.

The black hole was first identified using the European Space Agency's (ESA) Gaia spacecraft. Gaia has already discovered more than 800,000 multi-star systems. El-Badry and his team then sought to confirm the discovery through numerous additional observations over a period of four months. This effort involved six different highly sensitive telescopes across the world.

One was the 6.5-meter Magellan Baade telescope, based at the Las Campanas Observatory6 in Chile. The team also used an instrument on the Gemini North telescope, which is based in Hawaii.

The researchers needed such telescopes to effectively observe the orbital motion of the black hole's star. The telescope in Chile and the Gemini instrument were able to provide the astronomers with high-resolution images. The telescopes also collected sensitive data on ultraviolet and near-infrared wavelengths7.

El-Badry said in a statement the Gemini observations "confirmed beyond a reasonable doubt" that the team had discovered a normal star and at least one black hole. El-Badry added that the black hole appears to be dormant8, meaning not currently active.

When active, black holes give off high-energy light. While dormant, they give off nothing and are difficult to identify.

How did black hole form in our galaxy9?

The scientists said it remains10 unclear how the black hole formed in our Milky11 Way galaxy. Examinations of data collected on Gaia BH1 suggests "its existence is difficult to explain" using traditional evolutionary12 modeling methods, said Tineke Roegiers. She is a project information specialist with the Gaia spacecraft team.

The researchers said if the black hole formed the traditional way – from the gravitational collapse1 of a star – that star would have been at least 20 times the mass of our sun. This means the star would have only lived a short time, maybe only a few million years.

If both stars had formed at the same time, the scientists say, the massive star would have quickly turned into a "supergiant" and swallowed the other star before it had a chance to fully13 develop.

These differences, Roegiers said, "may indicate something important is missing from our current knowledge of black hole formation."

El-Badry said the mystery about Earth's closest black hole presents many questions about how it formed, "as well as how many of these dormant black holes there are out there."

He added, "I have been searching for a system like Gaia BH1 for the last four years, trying all kinds of methods – but none of them worked. It has been elating to see this search finally bear fruit."

Words in This Story

doubt – n. the feeling of being unsure about something

evolution – n. the way in which living things change and develop over millions of years

supergiant – n. an extremely large star that is from 10,000 to 100,000 times brighter than the sun

indicate – v. to suggest something

elate – adj. extremely happy and excited

bear fruit – idiom. if something bears fruit, it produces successful results


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1 collapse aWvyE     
vi.累倒；昏倒；倒塌；塌陷
参考例句：
  • The country's economy is on the verge of collapse.国家的经济已到了崩溃的边缘。
  • The engineer made a complete diagnosis of the bridge's collapse.工程师对桥的倒塌做了一次彻底的调查分析。
2 collapsed cwWzSG     
adj.倒塌的
参考例句：
  • Jack collapsed in agony on the floor. 杰克十分痛苦地瘫倒在地板上。
  • The roof collapsed under the weight of snow. 房顶在雪的重压下突然坍塌下来。
3 astronomers 569155f16962e086bd7de77deceefcbd     
n.天文学者，天文学家( astronomer的名词复数 )
参考例句：
  • Astronomers can accurately foretell the date,time,and length of future eclipses. 天文学家能精确地预告未来日食月食的日期、时刻和时长。 来自《简明英汉词典》
  • Astronomers used to ask why only Saturn has rings. 天文学家们过去一直感到奇怪，为什么只有土星有光环。 来自《简明英汉词典》
4 constellation CptzI     
n.星座n.灿烂的一群
参考例句：
  • A constellation is a pattern of stars as seen from the earth. 一个星座只是从地球上看到的某些恒星的一种样子。
  • The Big Dipper is not by itself a constellation. 北斗七星本身不是一个星座。
5 astronomical keTyO     
adj.天文学的，（数字）极大的
参考例句：
  • He was an expert on ancient Chinese astronomical literature.他是研究中国古代天文学文献的专家。
  • Houses in the village are selling for astronomical prices.乡村的房价正在飙升。
6 observatory hRgzP     
n.天文台，气象台，瞭望台，观测台
参考例句：
  • Guy's house was close to the observatory.盖伊的房子离天文台很近。
  • Officials from Greenwich Observatory have the clock checked twice a day.格林威治天文台的职员们每天对大钟检查两次。
7 wavelengths 55c7c1db2849f4af018e7824d42c3ff2     
n.波长( wavelength的名词复数 )；具有相同的/不同的思路；合拍；不合拍
参考例句：
  • I find him difficult to talk to—we're on completely different wavelengths. 我没法和他谈话，因为我们俩完全不对路。 来自《简明英汉词典》
  • Sunlight consists of different wavelengths of radiation. 阳光由几种不同波长的射线组成。 来自辞典例句
8 dormant d8uyk     
adj.暂停活动的；休眠的；潜伏的
参考例句：
  • Many animals are in a dormant state during winter.在冬天许多动物都处于睡眠状态。
  • This dormant volcano suddenly fired up.这座休眠火山突然爆发了。
9 galaxy OhoxB     
n.星系；银河系；一群(杰出或著名的人物)
参考例句：
  • The earth is one of the planets in the Galaxy.地球是银河系中的星球之一。
  • The company has a galaxy of talent.该公司拥有一批优秀的人才。
10 remains 1kMzTy     
n.剩余物，残留物；遗体，遗迹
参考例句：
  • He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
  • The remains of the meal were fed to the dog.残羹剩饭喂狗了。
11 milky JD0xg     
adj.牛奶的，多奶的；乳白色的
参考例句：
  • Alexander always has milky coffee at lunchtime.亚历山大总是在午餐时喝掺奶的咖啡。
  • I like a hot milky drink at bedtime.我喜欢睡前喝杯热奶饮料。
12 evolutionary Ctqz7m     
adj.进化的；演化的，演变的；[生]进化论的
参考例句：
  • Life has its own evolutionary process.生命有其自身的进化过程。
  • These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。
13 fully Gfuzd     
adv.完全地，全部地，彻底地；充分地
参考例句：
  • The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气，然后全部呼出。
  • They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。

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