VOA慢速英语--科学家称月球上的水比我们想象的要多

The moon may hold water in more places and in larger amounts than scientists have suggested in the past.

The finding is based on two studies – published in Nature Astonomy – that examined new data from the U.S. space agency NASA. The discovery could be important for planned, long-term human bases on the moon. It could mean that enough resources exist on the moon itself to provide drinking water and possibly help produce rocket fuel.

Until about 10 years ago, scientists believed the moon was mostly dry. Then, a series of findings provided evidence that water ice was widespread in small amounts on parts of the moon. The ice was thought to be in areas permanently¹ blocked from sunlight.

But in one of the new studies, NASA said it was able to confirm the presence of water molecules² on sunlit parts of the lunar surface. The space agency says the identification came from data collected by its SOFIA airborne observatory³. SOFIA is a Boeing 747SP aircraft equipped with a powerful telescope.

The research was led by Casey Honniball of NASA's Goddard Space Flight Center in Maryland. "Without a thick atmosphere, water on the sunlit lunar surface should just be lost to space," Honniball said in a statement. "Yet somehow we're seeing it. Something is generating the water, and something must be trapping it there."

Scientists have suggested the source of the water may have been comets, asteroids⁵, solar wind or interplanetary dust. The new research provides evidence the water may be surviving on sunlit lunar surfaces because it is attached to minerals.

"A lot of people think that the detection I've made is water ice, which is not true," Honniball told a news conference to announce the finding. "It's just the water molecules - because they're so spread out they don't interact with each other to form water ice or even liquid water."

The second study centered on so-called "cold traps" on the moon. These are areas of the lunar surface that exist in a state of permanent darkness where temperatures are below about minus 160 degrees Celsius⁶. Scientists say temperatures this cold can hold frozen water for billions of years.

Researchers say they were able to reconstruct the size of the cold traps and where they sit from images and temperature readings from NASA's Lunar Reconnaissance Orbiter. They identified cold traps as small as a few meters across and others as wide as 30 kilometers.

Planetary scientist Paul Hayne of the University of Colorado, Boulder⁷ led the research on cold traps. He estimated there are likely "tens of billions" of traps. "Since the little ones are too small to see from orbit, despite being vastly more numerous, we can't yet identify ice inside them," Hayne said. "Once we're on the surface, we will do that experiment."

Hayne's team says the new research suggests more than 40,000 square kilometers of the moon's surface may have the ability to trap water in the form of ice. That estimate is 20 percent bigger than predicted in the past, Hayne said.

Jacob Bleacher is the chief exploration scientist for NASA's Human Exploration and Operations Mission Directorate. He told reporters the agency believes it is very important to find out more about where the water came from and how accessible it is.

"Water is extremely critical for deep space exploration. It's a resource of direct value for our astronauts," Bleacher said. He noted⁸ that water is heavy and costly⁹ to transport from Earth.

"Anytime we don't need to pack water for our trip, we have an opportunity to take other useful items with us," he said. That may include materials that could be used to carry out bigger scientific experiments on the moon.

Words in This Story

generate – v. to produce something or to cause it to be produced

asteroid⁴ – n. objects made of rock and metal which orbit the sun, but are smaller than planets

detect – v. to discover or noticed the presence of something

vastly – adv. to a very great extend in an extremely large way

accessible – adj. able to be reached or to be used

opportunity – n. a period of time or situation when something can be done

1 permanently   

adv.永恒地，永久地，固定不变地

参考例句：

• The accident left him permanently scarred.那次事故给他留下了永久的伤疤。
• The ship is now permanently moored on the Thames in London.该船现在永久地停泊在伦敦泰晤士河边。

2 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。

3 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。

4 asteroid   

n.小行星；海盘车(动物)

参考例句：

• Astronomers have yet to witness an asteroid impact with another planet.天文学家还没有目击过小行星撞击其它行星。
• It's very unlikely that an asteroid will crash into Earth but the danger exists.小行星撞地球的可能性很小，但这样的危险还是存在的。

5 asteroids   

n.小行星( asteroid的名词复数 )；海盘车，海星

参考例句：

• Asteroids,also known as "minor planets",are numerous in the outer space. 小行星，亦称为“小型行星”，在外太空中不计其数。
• Most stars probably have their quota of planets, meteorids, comets, and asteroids. 多数恒星也许还拥有若干行星、流星、彗星和小行星。

6 Celsius   

adj.摄氏温度计的，摄氏的

参考例句：

• The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
• The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。

7 boulder   

n.巨砾；卵石，圆石

参考例句：

• We all heaved together and removed the boulder.大家一齐用劲，把大石头搬开了。
• He stepped clear of the boulder.他从大石头后面走了出来。

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 costly   

adj.昂贵的，价值高的，豪华的

参考例句：

• It must be very costly to keep up a house like this.维修这么一幢房子一定很昂贵。
• This dictionary is very useful,only it is a bit costly.这本词典很有用，左不过贵了些。