| A team of researchers has discovered the first evidence of water on the moon. A new type of chemical analysis has spotted the telltale signs of water molecules inside tiny beads of volcanic glass brought to Earth decades ago by the Apollo astronauts. The find may force astronomers to rethink their theories of how the moon formed, and it might mean that future missions could mine water from the lunar soil, helping to sustain colonists and fuel voyages to other planets. |
一组研究人员发现了月球上存在水的第一份证据。他们利用一种新的化学分析法，在小块火山玻璃珠里发现了水分子的明确迹象。玻璃珠是由“阿波罗”号宇航员于几十年前带回地球的。该发现也许会迫使天文学家们重新审视有关月球形成的理论。这也许意味着在将来的航天行动中可以从月球的土壤中挖到水源，有助于维持外来者的生命，并为前往其他行星的飞行提供燃料。 |
| Soon after it coalesced, about 4.5 billion years ago, Earth took a hit from a Mars-sized object. The resulting cloud of debris eventually condensed to form the moon--or so the current thinking goes. But if the moon came from Earth, and Earth is awash with water, where is the lunar water? |
目前的观点大致是这样的：大约45亿年前，地球刚刚形成一个整体后不久，一个火星大小的物体撞击了地球，撞出的大团残骸最终凝固而形成月球。但是，如果说月球来自地球，而地球充满了水，那么月球的水在哪里？ |
| Many planetary scientists think any water blown away from Earth by the impact would have been instantly vaporized by the high temperatures of the collision. Nevertheless, some researchers continue to believe that the moon does contain some water, perhaps locked deep within its interior. Over the years, they've intensely scanned tiny glass beads--brought back by the Apollo missions in the 1960s and 1970s--that had been ejected from inside the moon by volcanic eruptions about 3 billion years ago. Up to now, however, these samples have shown no evidence that the liquid ever existed on the moon. |
许多行星科学家们认为，地球遭到撞击产生了高温，被撞出去的水受到高温影响而立刻蒸发掉了。然而，一些研究人员仍然认为月球上确实含有水，也许被深深地封固在其内部。大约30亿年前，由于火山活动岩浆从月球内部喷射出来，冷却后形成了玻璃珠。20世纪60年代和70年代期间，宇航员们通过“阿波罗”号航天行动从月球带回了小块玻璃珠。多年来，研究人员一直在认真地察看这些玻璃珠。然而到目前为止，在这些玻璃珠样品里还没有发现月球上曾经存在水的证据。 |
| A team led by geochemist Alberto Saal of Brown University decided to use a more sensitive method. The technique, called secondary ion mass spectrometry, was developed to detect trace amounts of volatile gases such as chlorine and fluorine in Earth soil samples. Applying it to the lunar samples, the team found trace amounts of water--about 46 parts per million--in the volcanic beads. Because the water was embedded in the beads, it can't be a contaminant picked up since the samples arrived on Earth, the researchers report tomorrow in Nature. |
布朗大学的地球化学家艾伯托·萨尔领导的一个研究小组决定使用一种更为敏感的方法。这项技术叫做次级离子质谱法(SIMS)，本来是用来检测地球样土中氯、氟等微量挥发性气体的。研究小组将这项技术用于月球的采样，发现月球火山玻璃珠中存在微量的水——含量大约为百万分之46。研究人员在明天出版的《自然》杂志上报道说：由于水分含在玻璃珠内，所以不可能是样品到达地球时沾上的污染成分。 |
| Saal declines to speculate about how much water the moon contains or if any of it is still present in liquid form. Extrapolating the results to estimate the amount of lunar water would be like predicting "the final score of the game after we saw the first touchdown in the first 5 minutes of the first quarter," he says. Meanwhile, he and his team will be studying as many lunar glass beads as possible to refine their analysis. |
至于月球上含有多少水，或者是否仍然存在一些液态水，萨尔并没有进行推测。他说，用推测的方法对月球的含水量进行估计，就如同在橄榄球比赛时看到第一节前5分钟内的第一次触地得分后，就对整场比赛的最后得分进行预测一样。同时，萨尔及其研究小组还将研究尽可能多的月球玻璃珠，以便使自己的分析结果更加缜密。 |
| Planetary scientist David Stevenson of the California Institute of Technology in Pasadena calls the findings important and says they open up a new possibility. "It is likely that at the time of the giant impact, Earth had water and the impacting body had water," he says, so some of that water might still be trapped in the moon. |
帕萨迪纳市加州理工学院的行星科学家大卫·史蒂文森认为这些发现很重要。他说，这些发现提供了一种全新的可能性。“很可能在那次大碰撞之时，地球上有水，并且那颗撞来的天体也有水，”他说，“因此，那时候的一部分水可能仍然被困在月球里。” |
