VOA科学技术2023--Astronomers Observe Most Distant Organic Molecules in Universe

Astronomers² Observe Most Distant Organic Molecules³ in Universe

Scientists say they have observed the most distant organic molecules known to exist in the universe.

Astronomers made the discovery using the James Webb Space Telescope, operated by the American space agency NASA.

The kind of organic molecules observed are called polycyclic aromatic⁴ hydrocarbons⁵, or PAHs. These molecules are considered the basic building blocks for early forms of life. They have a complex structure and are found in many environments on our own planet. For example, PAHs can be found on Earth in smoke, burned materials and air pollution.

The molecules were discovered in a galaxy⁶ more than 12 billion light years from Earth. The scientists say this is the most distant observation of PAHs ever.

Past observations of PAHs have been difficult in distant galaxies⁷ because of limitations in infrared⁸ telescope technology. But the James Webb's sensitive instruments made the discovery possible, the researchers said.

The team said that because of the extreme distance involved, the light used to make the observation likely began traveling when the universe was less than 1.5 billion years old. This is about 10 percent of the universe's current age.

The astronomers recently reported their findings in a study in the publication Nature.

The targeted galaxy is known as SPT0418-47. Scientists had already identified it as a galaxy similar to our own Milky⁹ Way in several ways. But the amount of dust surrounding it made past observations difficult.

The researchers said telescope data permitted them to differentiate¹⁰ between infrared signals produced by larger dust particles and those produced by PAHs.

Justin Spilker is an astronomer¹ at Texas A&M University. He helped lead the research. He said in a statement that PAHs are "actually pretty common in space." But the latest research helped astronomers learn new things about them.

"Astronomers used to think they were a good sign that new stars were forming," Spilker said. "Anywhere you saw these molecules, baby stars were also right there..." Spilker noted¹¹ that the power of the James Webb telescope permitted the team to find many areas with smoke but no star formation.

The researchers said an observation method called gravitational lensing also helped them. This method involves observing how the gravity of large collections of galaxies can distort the light of more distant galaxies that sit behind the galaxy group, NASA explains. To distort means to change the natural or normal quality of something.

Joaquin Vieira is a professor of astronomy and physics at the University of Illinois Urbana-Champaign. He was a lead researcher on the project. Vieira said that the combined abilities of James Webb and gravitational lensing made it possible for the researchers to observe through the dust to identify the PAHs.

Observations of the targeted galaxy suggested it contained gas filled with heavy elements. This means that generations of stars had already lived and died there, the team said.

Vieira said the findings were completely unexpected and could be a "game-changer" for future observations of distant galaxies.

"This work is just the first step, and we're just now learning how to use (the telescope) and learn its capabilities¹²." He added, "We are very excited to see how this plays out."

The astronomers are looking forward to using the same equipment and methods to find out more about the early formation of the universe.

Texas A&M's Spilker said he is "excited to see all the new things" the James Webb can do for astronomers in the future.

"Detecting smoke in a galaxy early in the history of the universe? Webb makes this look easy," Spilker said. "Now that we've shown this is possible for the first time, we're looking forward to trying to understand whether it's really true that where there's smoke, there's fire," he added.

Words in This Story

organic – adj. used in chemistry to describe chemicals that contain carbon

galaxy – n. a very large group of stars held together in the universe

distort – v. to change the shape, sound or appearance of something

capability¹³ – n. the ability or power to do something

where there's smoke, there's fire - idiom a phrase meaning there are signs that something is true so it must be at least partly true

1 astronomer   

n.天文学家

参考例句：

• A new star attracted the notice of the astronomer.新发现的一颗星引起了那位天文学家的注意。
• He is reputed to have been a good astronomer.他以一个优秀的天文学者闻名于世。

2 astronomers   

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》

3 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

4 aromatic   

adj.芳香的，有香味的

参考例句：

• It has an agreeable aromatic smell.它有一种好闻的香味。
• It is light,fruity aromatic and a perfect choice for ending a meal.它是口感轻淡，圆润，芳香的，用于结束一顿饭完美的选择。

5 hydrocarbons   

n.碳氢化合物，烃( hydrocarbon的名词复数 )

参考例句：

• Hydrocarbons (HC), like carbon monoxide, represent unburned and wasted fuel. 碳氢化合物(HC)像一氧化碳一样，为未燃尽的和被浪费掉的燃料。 来自英汉非文学 - 环境法 - 环境法
• With this restricted frequency range it is not applicable to hydrocarbons. 这个较紧缩的频率范围不适用于烃类。 来自辞典例句

6 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。

7 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。

8 infrared   

adj./n.红外线(的)

参考例句：

• Infrared is widely used in industry and medical science.红外线广泛应用于工业和医学科学。
• Infrared radiation has wavelengths longer than those of visible light.红外辐射的波长比可见光的波长长。

9 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。

10 differentiate   

vi.(between)区分；vt.区别；使不同

参考例句：

• You can differentiate between the houses by the shape of their chimneys.你可以凭借烟囱形状的不同来区分这两幢房子。
• He never learned to differentiate between good and evil.他从未学会分辨善恶。

11 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。

12 capabilities   

n.能力( capability的名词复数 )；可能；容量；[复数]潜在能力

参考例句：

• He was somewhat pompous and had a high opinion of his own capabilities. 他有点自大，自视甚高。 来自辞典例句
• Some programmers use tabs to break complex product capabilities into smaller chunks. 一些程序员认为，标签可以将复杂的功能分为每个窗格一组简单的功能。 来自About Face 3交互设计精髓

13 capability   

n.能力；才能；(pl)可发展的能力或特性等

参考例句：

• She has the capability to become a very fine actress.她有潜力成为杰出演员。
• Organizing a whole department is beyond his capability.组织整个部门是他能力以外的事。