| 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. |
一組研究人員發(fā)現(xiàn)了月球上存在水的第一份證據(jù)。他們利用一種新的化學(xué)分析法，在小塊火山玻璃珠里發(fā)現(xiàn)了水分子的明確跡象。玻璃珠是由“阿波羅”號(hào)宇航員于幾十年前帶回地球的。該發(fā)現(xiàn)也許會(huì)迫使天文學(xué)家們重新審視有關(guān)月球形成的理論。這也許意味著在將來的航天行動(dòng)中可以從月球的土壤中挖到水源，有助于維持外來者的生命，并為前往其他行星的飛行提供燃料。 |
| 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? |
目前的觀點(diǎn)大致是這樣的：大約45億年前，地球剛剛形成一個(gè)整體后不久，一個(gè)火星大小的物體撞擊了地球，撞出的大團(tuán)殘骸最終凝固而形成月球。但是，如果說月球來自地球，而地球充滿了水，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. |
許多行星科學(xué)家們認(rèn)為，地球遭到撞擊產(chǎn)生了高溫，被撞出去的水受到高溫影響而立刻蒸發(fā)掉了。然而，一些研究人員仍然認(rèn)為月球上確實(shí)含有水，也許被深深地封固在其內(nèi)部。大約30億年前，由于火山活動(dòng)巖漿從月球內(nèi)部噴射出來，冷卻后形成了玻璃珠。20世紀(jì)60年代和70年代期間，宇航員們通過“阿波羅”號(hào)航天行動(dòng)從月球帶回了小塊玻璃珠。多年來，研究人員一直在認(rèn)真地察看這些玻璃珠。然而到目前為止，在這些玻璃珠樣品里還沒有發(fā)現(xiàn)月球上曾經(jīng)存在水的證據(jù)。 |
| 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. |
布朗大學(xué)的地球化學(xué)家艾伯托·薩爾領(lǐng)導(dǎo)的一個(gè)研究小組決定使用一種更為敏感的方法。這項(xiàng)技術(shù)叫做次級離子質(zhì)譜法(SIMS)，本來是用來檢測地球樣土中氯、氟等微量揮發(fā)性氣體的。研究小組將這項(xiàng)技術(shù)用于月球的采樣，發(fā)現(xiàn)月球火山玻璃珠中存在微量的水——含量大約為百萬分之46。研究人員在明天出版的《自然》雜志上報(bào)道說：由于水分含在玻璃珠內(nèi)，所以不可能是樣品到達(dá)地球時(shí)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態(tài)水，薩爾并沒有進(jìn)行推測。他說，用推測的方法對月球的含水量進(jìn)行估計(jì)，就如同在橄欖球比賽時(shí)看到第一節(jié)前5分鐘內(nèi)的第一次觸地得分后，就對整場比賽的最后得分進(jìn)行預(yù)測一樣。同時(shí)，薩爾及其研究小組還將研究盡可能多的月球玻璃珠，以便使自己的分析結(jié)果更加縝密。 |
| 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. |
帕薩迪納市加州理工學(xué)院的行星科學(xué)家大衛(wèi)·史蒂文森認(rèn)為這些發(fā)現(xiàn)很重要。他說，這些發(fā)現(xiàn)提供了一種全新的可能性?！昂芸赡茉谀谴未笈鲎仓畷r(shí)，地球上有水，并且那顆撞來的天體也有水，”他說，“因此，那時(shí)候的一部分水可能仍然被困在月球里?！?/SPAN> |
