研究：月球稀薄的大气层可能由陨石撞击形成

Scientists say new examinations of soil collected on the moon suggest its atmosphere might have been created by repeated meteorite strikes.
科学家表示，对从月球上采集的土壤的新检查表明，月球的大气层可能是由多次陨石撞击形成的。

Researchers studying the moon first used instruments to confirm it had an atmosphere in the early 1970s.
研究月球的科学家们首次在20世纪70年代初使用仪器确认月球有大气层。

The American space agency NASA explains the moon's atmosphere is “very thin and weak.”
美国航天局NASA解释说，月球的大气层“非常稀薄和微弱”。

It is technically considered an “exosphere.”
从技术上讲，它被认为是“外逸层”。

The newly examined soil was collected by NASA astronauts during America's Apollo program from 1969 to 1972.
新检查的土壤是由NASA宇航员在1969年至1972年美国阿波罗计划期间采集的。

The trips resulted in astronauts capturing about 382 kilograms of rocks and soil, called samples.
这些任务使宇航员捕获了约382公斤的岩石和土壤，被称为样本。

Instead of attempting to measure the moon's atmosphere in a direct way, investigators looked to the old soil material.
研究人员没有尝试以直接的方式测量月球的大气层，而是着眼于旧的土壤材料。

They theorized that the soil should contain residue material from atoms released into the lunar atmosphere over billions of years.
他们推测，土壤应该含有数十亿年来释放到月球大气层中的原子残留物。

The research was led by scientists at the University of Chicago and Massachusetts Institute of Technology (MIT).
这项研究由芝加哥大学和麻省理工学院（MIT）的科学家们领导。

Their results recently appeared in a study in the publication Science Advances.
他们的研究结果最近发表在《科学进展》杂志的一项研究中。

Nicole Nie was the lead writer of the study.
妮可·倪是该研究的主要作者。

She is a planetary scientist at MIT.
她是麻省理工学院的行星科学家。

Meteorite impacts
陨石撞击

Nie said that when meteorites impact, or hit, an object like the moon, they create very high temperatures.
倪说，当陨石撞击或击中像月球这样的物体时，它们会产生非常高的温度。

Such strikes can heat up the surface by 2,000 to 6,000 degrees Celsius.
这种撞击可以使表面加热到2000至6000摄氏度。

These extreme temperatures melt and vaporize rocks at the surface and release atoms contained in dust and soil into the atmosphere.
这些极端温度会融化并汽化表面的岩石，并将尘土和土壤中的原子释放到大气中。

Some of the atoms end up being pushed into space, while others remain just above the surface.
其中一些原子最终被推入太空，而另一些则停留在表面上方。

The researchers said the soil examinations led to the discovery that the moon's atmosphere was formed through a process known as “impact vaporization.”
研究人员表示，土壤检查导致了发现月球的大气层是通过一种被称为“撞击汽化”的过程形成的。

Nie and her team centered their examinations on two main elements – potassium and rubidium.
倪和她的团队将检查集中在两个主要元素上——钾和铷。

These substances were chosen because they can easily be vaporized by meteorite hits.
选择这些物质是因为它们很容易被陨石撞击汽化。

The process involved studying the behaviors of different kinds of isotopes found in potassium and rubidium.
该过程涉及研究在钾和铷中发现的不同种类同位素的行为。

That study persuaded the team that repeated meteorite strikes formed the atmosphere.
这项研究让团队相信，多次陨石撞击形成了大气层。

In the past, studies have shown the moon's atmosphere might have been created by either meteor activity or the solar wind.
过去的研究表明，月球的大气层可能是由陨石活动或太阳风形成的。

Solar wind describes a continuous flow of charged particles from the sun that spreads across the solar system.
太阳风是指来自太阳的带电粒子的连续流动，它遍布整个太阳系。

The researchers said the latest study provides new evidence that most of the lunar atmosphere was likely formed by repeated meteorite hits over billions of years.
研究人员表示，最新研究提供了新的证据，表明大部分月球大气层可能是由数十亿年来反复的陨石撞击形成的。

After testing 10 samples of lunar soil, the team concluded that much more of the atmosphere is due to meteor activity than to the solar wind.
在测试了10个月球土壤样本后，团队得出结论，月球大气层的形成更多是由于陨石活动，而非太阳风。

“At least 70 percent of the lunar atmosphere is created by these meteorite impacts,” Nie said in a statement.
“至少70%的月球大气层是由这些陨石撞击形成的，”倪在一份声明中说。

“A much smaller percentage is created by the solar wind abrasion of the surface,” she added.
“更小的一部分是由太阳风对表面的磨蚀形成的，”她补充道。

Nicolas Dauphas is a professor of geophysical sciences at the University of Chicago.
尼古拉斯·道法斯是芝加哥大学地球物理科学的教授。

He helped lead the research.
他帮助领导了这项研究。

Dauphas said, “It turns out the answer to this longstanding question was right in front of us – preserved in lunar soil brought back to Earth by the Apollo missions.”
道法斯说：“结果表明，这个长期存在的问题的答案就在我们面前——保存在阿波罗任务带回地球的月球土壤中。”

Nie said understanding such processes can be extremely valuable to planning future missions to the moon, Mars and beyond.
倪说，了解这些过程对于规划未来的月球、火星及其他任务非常有价值。

“If humans want to move to different planetary bodies someday, we will have to understand what's going on at the surface to be able to prepare.”
“如果人类有一天想要移居到不同的行星体，我们必须了解表面上发生的事情，以便做好准备。”

She added, “Each planetary body is different, and the more we understand about these processes, the more complete picture we'll have.”
她补充说：“每个行星体都是不同的，我们对这些过程了解得越多，我们就会有更完整的图景。”