VOA科学技术2023--NASA Finds Material that Could Support Possible Life on Saturn’s Moon

NASA Finds Material that Could Support Possible Life on Saturn¹’s Moon

NASA has discovered new evidence that Saturn's moon Enceladus holds material that is important to the early development of life.

The American space agency said the new evidence came from observations made by its Cassini spacecraft. Cassini spent seven years observing seasonal² changes around Saturn. During that time, the spacecraft also collected data on Saturn's moons.

Two of Cassini's discoveries involved Saturn's moons Titan and Enceladus. In its observations of Titan, the spacecraft studied the moon's climate activity and recorded data on rivers, lakes and oceans. Cassini also found evidence of several Earth-like qualities of Titan that could support life.

Another Cassini discovery involved the observation of hydrogen molecules⁴ in ice particles and vapor⁵ shooting upward from the moon's surface. Researchers announced that finding in 2017, the same year Cassini officially ended its mission.

In announcing that discovery, NASA scientists said the presence of hydrogen molecules could signal deep-sea chemical reactions between water and rock that could create microbial life.

Now, the space agency is sharing a new finding that supports the earlier discoveries. Scientists examining Cassini data said they identified "strong confirmation⁶" of the presence of another molecule³ seen as important for enabling life.

Evidence of the molecule – hydrogen cyanide – was found in data relating to the same shooting flows of ice and water vapor observed by Cassini on Enceladus.

The team used data collected by an instrument aboard Cassini designed to measure the activity of gas, ions and ice particles around Saturn. The discovery process involved a lot of mathematics aiming to understand the newly examined data.

The new evidence is described in a study in Nature Astronomy by scientists from NASA's Jet Propulsion Laboratory (JPL) in California.

The lead writer of the study, Jonah Peter, is currently a doctoral student at Harvard University. He called the discovery of hydrogen cyanide "particularly exciting," saying the molecule is "the starting point for most theories on the origin of life."

NASA said in a statement that for life to exist in space, there must be collections of the right building blocks. One of the most important of these is amino acids. "Hydrogen cyanide is one of the most important and versatile⁷ molecules needed to form amino acids," NASA noted⁸.

The researchers said hydrogen cyanide molecules can join together in many different combinations. They can also serve as a "precursor⁹" for different kinds of amino acids.

In addition, the latest examination of Cassini data suggested the underground ocean on Enceladus "holds a powerful source of chemical energy." The ocean sits beneath the moon's icy surface.

"Unidentified until now, the energy source is in the form of several organic compounds, some of which, on Earth, serve as fuel for organisms," NASA said.

Astronomers¹⁰ involved in the research said that the discovery provides fresh evidence that there may be more chemical energy inside Enceladus than previously¹¹ thought. The more energy that is available, the team said, the more likely it is that life can form and survive.

"Not only does Enceladus seem to meet the basic requirements for habitability," said JPL's Jonah Peter, "we now have an idea about how complex biomolecules could form there, and what sort of chemical pathways might be involved."

The search for possible life on Titan will continue when NASA launches its Dragonfly exploratory mission in 2026. Dragonfly is a drone, or pilotless aircraft. The vehicle is designed to capture images and also land on Titan to collect data.

Tom Nordheim is a planetary scientist at JPL who helped lead the research. He noted that although NASA purposely sent the spacecraft crashing into Saturn's atmosphere to end its service, Cassini is still proving to be a valuable research tool.

"Our study demonstrates that while Cassini's mission has ended, its observations continue to provide us with new insights about Saturn and its moons..." Nordheim said.

Words in This Story

vapor – n. many small drops of liquid that form in the air

mission – n. an important job or task, often involving travel to somewhere

ion – n. an atom or small group of atoms that has an electrical charge because it has added or lost electrons

origin – n. where something begins or comes from

versatile – adj. using for doing a lot of different things

precursor – n. something that happens or exists before something else and influences its development

insight – n. a thing that helps someone gain a deeper understanding of something

habitability –n. able to support living in or on

1 Saturn   

n.农神，土星

参考例句：

• 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。
• These comparisons suggested that Saturn is made of lighter materials.这些比较告诉我们，土星由较轻的物质构成。

2 seasonal   

adj.季节的，季节性的

参考例句：

• The town relies on the seasonal tourist industry for jobs.这个城镇依靠季节性旅游业提供就业机会。
• The hors d'oeuvre is seasonal vegetables.餐前小吃是应时蔬菜。

3 molecule   

n.分子，克分子

参考例句：

• A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
• This gives us the structural formula of the molecule.这种方式给出了分子的结构式。

4 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。

5 vapor   

n.蒸汽，雾气

参考例句：

• The cold wind condenses vapor into rain.冷风使水蒸气凝结成雨。
• This new machine sometimes transpires a lot of hot vapor.这部机器有时排出大量的热气。

6 confirmation   

n.证实，确认，批准

参考例句：

• We are waiting for confirmation of the news.我们正在等待证实那个消息。
• We need confirmation in writing before we can send your order out.给你们发送订购的货物之前，我们需要书面确认。

7 versatile   

adj.通用的，万用的；多才多艺的，多方面的

参考例句：

• A versatile person is often good at a number of different things.多才多艺的人通常擅长许多种不同的事情。
• He had been one of the game's most versatile athletes.他是这项运动中技术最全面的运动员之一。

8 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。

9 precursor   

n.先驱者；前辈；前任；预兆；先兆

参考例句：

• Error is often the precursor of what is correct.错误常常是正确的先导。
• He said that the deal should not be seen as a precursor to a merger.他说该笔交易不应该被看作是合并的前兆。

10 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》

11 previously   

adv.以前，先前（地）

参考例句：

• The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
• Let me digress for a moment and explain what had happened previously.让我岔开一会儿，解释原先发生了什么。