VOA科学技术2024--Scientists Discover 'Awakening' Center of a Distant Galaxy

Space researchers have observed a big increase in energy at the center of a distant galaxy¹ caused by a very large black hole. They say the discovery could be meaningful for our own Milky² Way galaxy.

In a recent research paper, space scientists said a huge black hole at the center of a galaxy called SDSS1335+0728 brightened by a large amount in several wavelengths³ of light.

A black hole is a collapsed⁴ star or group of stars whose gravity is so great even light cannot escape.

The European Southern Observatory⁵ (or ESO) in Germany announced the discovery on June 18.

One explanation for the brightening of SDSS1335+0728 is that the black hole at its center is just "awakening⁶." That means it is bringing in nearby material, which causes a huge release of energy.

Earth-based and orbiting telescopes were used to make observations of the galaxy. It is about 360 million light-years from Earth in the constellation⁷ of Virgo. A light year is the distance light travels in one year.

The black hole in the distant galaxy has the same mass as about one million suns. Because it is so massive, the black hole captures stars and any other material around it. This material forms a structure called an "accretion⁸ disk" around the mouth of the black hole. The matter there reaches an extremely high temperature and can outshine the galaxy containing it.

Scientists call this an "active galactic nucleus⁹."

Lorena Hernandez Garcia is with the University of Valparaiso in Chile and was a co-writer of the study. She said sometimes black holes shoot jets of high-energy particles into space, but none has been identified in this case.

Paula Sanchez Saez is an astrophysicist with the ESO and was the lead writer of the report. She said this kind of galaxy nucleus releases huge amounts of energy including radio waves and gamma rays. She also said the centers of galaxies¹⁰ such as these "are considered the most luminous¹¹ objects in the universe."

The change in the luminosity of the galactic center was first identified in 2019. It has been increasing since then.

But exactly why this galaxy has become activated¹² is unclear. "At the moment, we do not know," Sanchez said.

"It could be a natural process of the galaxy," Hernandez said adding, "We know that a galaxy passes through different phases of activity and non-activity during its lifetime."

The researchers say the latest discovery might be the awakening of a galactic nucleus or it might be a new kind of galactic event.

Scientists say there is a huge black hole at the center of the Milky Way galaxy. It is called Sagittarius A*. It is currently considered dormant¹³, or asleep. But that could change.

Hernandez said, because it is 26,000 light-years away, such an event would likely not affect Earth. "...if it activates¹⁴, we would not notice because we are very far from the center," Hernandez noted¹⁵.

Words in This Story

galaxy -n. a huge grouping of stars, gas and dust

disk -n. a round, flat form

nucleus -n. the center of a cell, atom or galaxy

luminous -adj. something that is bright because it shines

phase -n. one of several states of a thing that can change with time

1 galaxy   

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。

2 milky   

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。

3 wavelengths   

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

4 collapsed   

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。

5 observatory   

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。

6 awakening   

n.觉醒，醒悟 adj.觉醒中的；唤醒的

参考例句：

• the awakening of interest in the environment 对环境产生的兴趣
• People are gradually awakening to their rights. 人们正逐渐意识到自己的权利。

7 constellation   

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。

8 accretion   

n.自然的增长，增加物

参考例句：

• Every culture is an accretion.每一种文化都是长期积淀的结果。
• An accretion of sediment at the mouth of the river caused serious flooding.河口堆积物的增加导致河水严重泛滥。

9 nucleus   

n.核，核心，原子核

参考例句：

• These young people formed the nucleus of the club.这些年轻人成了俱乐部的核心。
• These councils would form the nucleus of a future regime.这些委员会将成为一个未来政权的核心。

10 galaxies   

星系( galaxy的名词复数 )； 银河系； 一群（杰出或著名的人物）

参考例句：

• Quasars are the highly energetic cores of distant galaxies. 类星体是遥远星系的极为活跃的核心体。
• We still don't know how many galaxies there are in the universe. 我们还不知道宇宙中有多少个星系。

11 luminous   

adj.发光的，发亮的；光明的；明白易懂的；有启发的

参考例句：

• There are luminous knobs on all the doors in my house.我家所有门上都安有夜光把手。
• Most clocks and watches in this shop are in luminous paint.这家商店出售的大多数钟表都涂了发光漆。

12 activated   

adj. 激活的 动词activate的过去式和过去分词

参考例句：

• The canister is filled with activated charcoal.蒸气回收罐中充满了活性炭。

13 dormant   

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。

14 activates   

使活动，起动，触发( activate的第三人称单数 )

参考例句：

• Activates the window and displays it in its current size and position. 激活窗口，保持当前的大小及位置不变。
• Pulling out the alarm switch activates alarm and pushing it deactivates it. 闹钟的开和关是通过拔出和按入闹铃开关实现的。

15 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。