本帖最后由 gohomeman1 于 2009-9-28 23:17 编辑
今天的APOD是前几天公布的一个大新闻——月球上找到了水
http://apod.nasa.gov/apod/ap090928.html 本楼的翻译来自北京天文馆http://www.bjp.org.cn/apod/today.htm
2009 September 28
Water Discovered on the Moon
Credit: ISRO/NASA/JPL-Caltech/USGS/Brown U.
Explanation:
Water has been discovered on the surface of the Moon. No lakes have been found, but rather NASA's Moon Mineralogy Mapper aboard India's new Chandrayaan-1lunar orbiter radios back that parts of the Moon's surface absorb a very specific color of light identified previously only with water.Currently, scientists are trying to fit this with other facts about theMoon to figure out how much water is there, and even what form this water takes. Unfortunately, even the dampest scenarios leave our moon dryer than the driest of Earth's deserts. A fascinating clue being debated is whether thewater signal rises and falls during a single lunar day. If true, the signal might be explainable by hydrogen flowing out from the Sun and interacting withoxygen in the lunar soil. This could leave an extremely thin monolayer of water, perhaps only a few molecules thick.Some of the resulting water might subsequently evaporate away in bright sunlight.Pictured above, the area near a crater on the far side of the Moon shows a relatively high abundance of water-carrying minerals in false-color blue. Next week, the new LCROSS satellite will release an impactor that will strike a permanently shadowed crater near the lunar south pole to see if any hidden water or ice sprays free there.
月球上发现的水
影像提供:ISRO/NASA/JPL-Caltech/USGS/Brown U.
说明:
在月球的表明已经发现了水。在月球表面没有湖,但是装载在印度初航-1号月球探测器上的NASA月球矿物测绘仪发回无线电信号,其中显示部分月球表面吸收了特定的波段,先前已经被证明只有水才吸收这种波段。如今,科学家们正在努力将此信息与月球的其他信息匹配起来,确定那里有多少水存在,并且是什么形成了这片水域。不幸的是,甚至是月球上最潮湿的地方比地球最干燥的地方还要干燥。一条吸引人的线索正引起争论,那就是水源信号是否在一个月球天内上升或者削弱。如果是真的,那么该信号可能是太阳上的氢与月壤内的氧原子结合后形成。这可能会留下极度稀薄的单分子水层,也可能仅有数个分子厚而已。形成的水有些可能是随后在明亮的阳光下蒸发。上面的影像是月背面环形山附近的一片区域显示了相对较高的水矿物,其以蓝色显示。下周,新的LCROSS卫星将会在月球南极释放一颗撞击器进行撞击,那将会在形成一个永夜下的陨石坑,进一步了解是否有水或冰隐藏在月球表面。 |