VOA科学技术2023--All Elements for Life Found on Saturn's Icy Moon Enceladus

All Elements for Life Found on Saturn¹'s Icy Moon Enceladus

An international team of scientists says it has found high levels of phosphorus in ice from Saturn's moon Enceladus.

Phosphorus is a necessary element for many biological processes on Earth.

The researchers said the ice crystals shot out from an ocean beneath the moon's surface.

The discovery came from data collected by NASA's Cassini spacecraft. Cassini collected the data during its 13-year exploration of the huge planet, its rings, and its moons from 2004 to 2017. Cassini was the first spacecraft to orbit Saturn.

The German-led team published their findings in Nature, a science magazine. NASA's Jet Propulsion Laboratory (JPL) in the western U.S. state of California also announced the findings. JPL designed and built the Cassini spacecraft.

Earlier, the same team confirmed that Enceladus' ice grains are rich in minerals and complex organic compounds. The team said the ice includes the necessary elements to create amino acids, which are important molecular² structures for life.

Phosphorus is the least common of the six chemical elements considered necessary to all living things. The others are carbon, oxygen, hydrogen, nitrogen, and sulfur³. Now, scientists have found them all on Enceladus.

"It's the first time this essential element has been discovered in an ocean beyond Earth," said the study's lead writer, Frank Postberg. He is a planetary scientist at the Free University in Berlin in Germany.

Phosphorus is necessary for DNA⁴, the genetic⁵ instructions in cells. It is also an important part of energy formation and transportation in life on Earth.

The researchers studied measurements taken by Cassini as it passed through salt-rich ice grains released into space by geysers found on the southern part of the moon. The geysers were erupting from the ice-covered ocean beneath the surface of Enceladus.

The substances are the same material that creates one of Saturn's rings, called the "E" ring. The E ring can be found outside the planet's brighter main rings.

Cassini discovered the ice-covered ocean. Since then, Enceladus has been a favorable target in the search for places in our solar system that could support life. Enceladus is about one-seventh the size of Earth's moon and the sixth largest among Saturn's 146 known natural satellites.

Jupiter's moon Europa is also believed to have an ocean beneath its icy surface.

Computer modeling by the study's co-writers in Europe and Japan shows that phosphorus exists in concentrations at least 100 times higher than in Earth's oceans.

Christopher Glein is a planetary scientist at Southwest Research Institute in San Antonio, Texas. He took part in the research. He said the discovery was important. Glein said there could be enough phosphorus to support life in Enceladus' ocean.

The scientists noted⁶ that finding phosphorus, complex organic compounds, water, and other things is evidence that Enceladus could possibly support life. Life, either past or present, has not been confirmed anywhere beyond Earth.

"Whether life could have originated in Enceladus' ocean remains⁷ an open question," Glein added.

Words in This Story

spacecraft – n. a vehicle that is used for travel in outer space

crystal –n. a form of a mineral in which the molecules⁸ are ordered in a regular way

rings – n. something that is shaped like a circle

grain –n. any very small, rounded object

organic – adj. of, relating to, substances that contain the element carbon and which are necessary for life

essential –adj. extremely important and necessary

geyser – n. a hole in the ground that shoots out hot water and steam

erupt – v. to send out rocks, ash, or lava⁹ in a sudden explosion

concentration – n. the amount of an ingredient in a mixture

 

originate – v. to begin to exist

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 molecular   

adj.分子的；克分子的

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。
• For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时，分子的碰撞就停止了。

3 sulfur   

n.硫，硫磺（=sulphur）

参考例句：

• Sulfur emissions from steel mills become acid rain.炼钢厂排放出的硫形成了酸雨。
• Burning may produce sulfur oxides.燃烧可能会产生硫氧化物。

4 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

5 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

6 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。

7 remains   

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。

8 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。

9 lava   

n.熔岩，火山岩

参考例句：

• The lava flowed down the sides of the volcano.熔岩沿火山坡面涌流而下。
• His anger spilled out like lava.他的愤怒像火山爆发似的迸发出来。