Astronomers have found patches of frost scattered around the moon’s north and south poles which could one day provide a source of water for human visitors.

The scientists spotted the telltale signature of frozen water in infrared measurements taken by NASA’s moon mineralogy mapper, an instrument that flew on India’s Chandrayaan-1 mission to the moon a decade ago.

The freshly-analyzed data show that water ice lurks on the ground in a number of spots near the moon’s polar regions that are permanently in shade and so sheltered from the heat of the sun’s rays.

Most of the ice was found near the moon’s south pole around a cluster of craters named after scientists and explorers, including Haworth, Shoemaker, Sverdrup and Shackleton. In the north, the patches of ice appeared to be more isolated, according to Li Shuai at the Hawaii Institute of Geophysics and Planetology in Honolulu.

Follow-up measurements of the ice patches found that they tended to form where the surface temperature never crept above -163 degrees Celsius, but temperature alone was not enough to guarantee frozen water. Only 3.5 percent of the shadowy areas the scientists checked for water revealed notable signs of ice.

The images are the first “direct and definitive evidence” of water ice that is exposed on the surface of the moon, according to a report in the Proceedings of the National Academy of Sciences. “These ice deposits might be utilized as an in situ resource in future exploration of the moon,” the authors write.

The Indian Space Agency launched its Chandrayaan-1 mission to the moon in 2008 and was swiftly rewarded with evidence of frozen water on the lunar surface a year later. Rather than sheets of ice on the surface, the water is thought to exist as water molecules bound to grains of moon dust.

Soon after the Indian feat, NASA crashed a spacecraft into the 100-kilometer-wide Cabeus crater, which is in permanent shade on the moon’s south pole. The intentional act of lunar violence threw up a plume of debris from which scientists were able to confirm the presence of water on the moon.

Words to Learn 相关词汇

【矿物学】kuàngwùxué mineralogy a science dealing with minerals, their crystallography, properties, classification and the ways of distinguishing them

【当地】dāngdì in situ locally, on site

天文学家发现，一片片冰霜区零星分布在月球的北极和南极周边。将来，它们可以为人类访客提供水源。

科学家们在美国航天局的月球矿物绘图仪取得的红外测量结果中发现了这些冰冻水的痕迹。这个月球矿物绘图仪于10年前搭乘印度的“月船1号”探测器飞抵月球。

对有关数据的最新分析显示，月球两极地区附近的多数地表分布着水冰。月球的两极地区常年处于阴暗中，终年不见阳光。

大部分的冰是在月球南极附近一系列环形山的周边发现的。这些环形山都以科学家和探险家的名字命名，包括霍沃思、休梅克、斯韦德鲁普和沙克尔顿。夏威夷檀香山地球物理与行星学研究所的李帅（音）说，月球北极的水冰似乎分散一些。

对这些冰霜区的后续测量发现，在表面气温从不超过零下163摄氏度的地方最可能形成冰。但温度本身不足以保证出现冰冻的水：科学家探测水源经过的阴暗地区中只有3.5%的区域显示出明显的水冰迹象。

美国《国家科学院学报》期刊发表的一篇报告说，这些图片是月球表面存在水冰的首个“直接和明确证据”。作者们写道：“在未来的探月活动中，这些冰或许能作为一种当地资源加以利用。”

印度航天局2008年发射了“月船1号”探月器。一年后，该探月器就找到了月球表面存在冰冻水的证据。人们认为，月球上的水以水分子的形式存在，它们同月球灰尘结合在一起，而不是以月球表面的冰层形式存在。

印度的这项发现之后不久，美国航天局将一个航天器撞向位于月球南极永久阴影区、直径100公里的卡贝乌斯环形山。这次有意为之的撞击扬起了许多碎屑，科学家们由此才能确认月球上水的存在。 (Chinadaily.com.cn)