VOA科学技术2024--Scientists Learn More about Black Hole at Center of Our Galaxy

Scientists Learn More about Black Hole at Center of Our Galaxy¹

　　Researchers recently announced that they have found qualities of the main black hole in our Milky² Way Galaxy that they did not know about before.

　　Black holes are very massive objects with gravity so strong that even light cannot escape them.

　　The space scientists said they found a strong and organized magnetic field around the black hole called Sagittarius A*. It is at the center of our galaxy 26,000 light years away.

　　Activity at the edge of the black hole is believed to have created the magnetic field. It is similar to activity surrounding the only other black hole ever imaged. That one is at the center of a nearby galaxy commonly called M87.

　　The researchers wondered if their finding suggests that strong magnetic fields might be a quality common to all black holes.

　　Black holes and jets

　　The magnetic field around the M87 black hole, called M87*, causes it to launch powerful jets of material into space, the researchers said. They added that while such jets have not yet been found near Sagittarius A*, they might exist and might be observable in the near future.

　　The researchers released the image showing the environment around Sagittarius A* in polarized light for the first time.

　　In a way, light behaves like a wave. Light waves can move in different directions. When light waves are restricted to one direction, or plane, the result is polarized light.

　　The latest image came from the Event Horizon Telescope (EHT). It is an international network of observatories³ working together to study radio waves connected with black holes. The EHT also provided the earlier image of the M87 black hole.

　　Sara Issaoun is with the Center for Astrophysics - Harvard & Smithsonian. Issaoun said scientists can "see" black holes: "By imaging polarized light from hot glowing gas near black holes, we are directly inferring the structure and strength of the magnetic fields..."

　　She said observing polarized light made the new study different: "Compared to the previous results, polarized light teaches us a lot more about the astrophysics, the properties of the gas, and mechanisms⁵ that take place as a black hole feeds."

　　A co-leader of the research, Issaoun said: "For a while, we've believed that magnetic fields play a key role in how black holes feed and eject matter in powerful jets."

　　"This new image...shows that strong and ordered magnetic fields are critical to how black holes interact with the gas and matter around them."

　　Angelo Ricarte is another researcher from the Center for Astrophysics who was involved with the study. Ricarte said: "The magnetic field appears to be organized into a spiral, similar to M87*. This magnetic field geometry implies that the black hole can power very efficient jets that shoot off into the galaxy,"

　　The M87 black hole has a mass 6 billion times that of our sun — much bigger than the one in our Milky Way. It ejects a powerful jet visible in all wavelengths⁶ of light.

　　The evidence for a jet flowing from Sagittarius A* is growing.

　　Ricarte said that researchers are hopeful about the prediction for a powerful jet in the Milky Way's black hole. As tools get better in the coming years, he said, researchers should be able to better understand the issue from the data.

　　The researchers' findings appeared recently in Astrophysical Journal Letters.

　　Words in This Story

　　light year –n. a measure equal to the distance light travels in space or 9.5 trillion kilometers

　　polarize – v. to restrict something, such as light waves, so that they only move in one direction or plane

　　mechanism⁴ – n. a process or system that is used to produce a particular result

　　eject – v. to push (something) out with force

　　critical – adj. extremely important

　　interact – v. to come together and have an effect on each other

　　spiral – n. a circular curving line that goes around a central point while getting closer to or farther away from it

　　imply – v. to include or involve (something) as a natural or necessary part

　　efficient – adj. capable of producing desired results without wasting materials, time, or energy

　　infer – v. to reach (a conclusion) based on known facts

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 observatories   

n.天文台，气象台( observatory的名词复数 )

参考例句：

• John Heilbron, The Sun in the Church: Cathedrals as Solar Observatories, 3-23. 约翰．海耳布隆，《教会里的太阳：教堂即太阳观测台》，第3-23页。 来自互联网
• Meteorologists use satellites, land observatories and historical data to provide information about the weather. 气象学家使用卫星、上天文台和历史资料来提供有关天气的信息。 来自互联网

4 mechanism   

n.机械装置；机构，结构

参考例句：

• The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
• The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。

5 mechanisms   

n.机械( mechanism的名词复数 )；机械装置；[生物学] 机制；机械作用

参考例句：

• The research will provide direct insight into molecular mechanisms. 这项研究将使人能够直接地了解分子的机理。 来自《简明英汉词典》
• He explained how the two mechanisms worked. 他解释这两台机械装置是如何工作的。 来自《简明英汉词典》

6 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