彭蒙惠英语:20110215 MP3在线课程 NEWSworthy Clips

时间 : 2013-12-13 07:48来源 : VOA官网 收听下载次数 :
下载音频

Moon has more water than previously thought

by Amina Khan / (c) 2010, Los Angeles Times. Distributed by MCT.

The moon is much wetter and more chemically complicated than scientists had believed, according to data released in October by NASA.

In 2009, after the space agency dropped a rocket into a frozen crater near the moon's south pole and measured the stuff kicked up by the collision, scientists calculated that the crater contained about 25 gallons of water. But further analysis over the past 11 months indicates that the amount of water vapor and ice was closer to 41 gallons.

"It's twice as wet as the Sahara Desert," said Anthony Colaprete, the lead scientist for the Lunar Crater Observation and Sensing Satellite (LCROSS) mission at NASAAmes Research Center in Northern California.

The instruments aboard the satellite, including near- infrared and visible light spectrom eters, scanned the debris cloud and identified the compounds it contained. They determined that about 5.6 percent of the plum e was made of water, give or take 2.9 percent. It also included a surprising variety of chemicals, including mercury, methane, silver, calcium, magnesium, pure hydrogen and carbon monoxide.

The findings were reported in six related papers published online by the journal Science.

"The lunar 'closet' is really at the poles, and I think there's a lot of stuff crammed into the closet that we really haven't investigated yet," said Peter Schultz, a planetary geologist at Brown University and one of the LCROSS team members.

The new measurements allowed Colaprete to estimate that the crater could hold as much as 1 billion gallons of water.

That might be handy for space explorers who might use the moon as an interplanetary way station. The water could be used for drinking and be mined for breathable oxygen. It also could be used to make hydrogen fuel for long-distance spacecraft.

月球上的水量多于先前的推测

美国航空暨太空总署在十月公布的资料指出,月球的含水量和化学成分的复杂度都远比科学家先前以为的还高。

二00九年,太空总署把一具火箭投入月球南极附近的一座冰冻月坑,并且测量了撞击扬起的物质,结果科学家计算出那座月坑含有二十五加仑左右的水。然而,过去十一个月以来的分析发现,水蒸气与冰的量比较接近四十一加仑。

「那里的含水量是撒哈拉沙漠的两倍,」安东尼.卡拉普瑞特如此表示。他是北加州太空总署艾姆斯研究中心的月坑观察与感测卫星(简称LCROSS)任务小组的首席科学家。

那颗卫星上的仪器──包括近红外线与可见光的光谱仪──扫描了碎屑烟云,并且辨识了其中所含的化合物。结果发现,那团烟云有约百分之五点六是水,正负误差值为百分之二点九。出乎意料的是,那团烟云也含有极为多样化的化学物质,包括汞、甲烷、银、钙、镁、纯氢与一氧化碳。

这些发现发表于六份彼此相关的论文里,由《科学》期刊刊登在网路上。

「月球的『密室』其实位于两极地带,而且我认为那座密室里塞藏了许多东西,我们都还没真正研究过,」彼得.舒茨表示。他是布朗大学的行星地质学家,也是LCROSS的团队成员。

卡拉普瑞特利用新的测量结果进行估计,发现这月坑可以含纳高达十亿加仑的水量。

这项发现对于可能利用月球做为星际中继站的太空探险家来说颇为便利。(月球上的)水可以拿来饮用,也可以用于制造可供呼吸的氧气。此外,也可以生产氢燃料以供长程航行的太空船使用。

Easyvoa与空中英语教室吉林出版社合作,推出空中英语在线学习内容,为保护版权,不影响空英的杂志销售,只提供两年前空英的学习资料。如果您喜欢空中英语教室,欢迎加入 Easyvoa空英群115390136。