| In a blow to hopes for finding water and life on Mars, scientists think bright streaks detected inside Martian gullies after 1999 were not spurts of water, but rather avalanches of dust. |
科学家们认为，1999年以后在火星沟壑里发现的明亮条痕并不是涌出的水流，而是顺坡而下的尘埃，致使在火星上找到水和生命的希望受挫。 |
| Water is thought to have covered much of Mars in the past, but whether or not the life-giving substance has shown up in the recent past is a matter of debate among scientists. |
科学家们认为，过去水曾经覆盖着火星的大部分表面。但是，至于不久前火星上是否出现过孕育生命的物质，在科学家们当中是个颇有争议的问题。 |
| The strange, streaky formations were not present in Mars Global Surveyor 1999 images of the gullies. Seven years later, however, the bright streaks made their debut in new images, prompting Michael Malin of Malin Space Science Systems and his colleagues to conclude that a recent burst of Martian groundwater might be responsible. |
这些奇特的条痕构造并没有出现在1999年火星环球探测器所拍下的图像中。然而，七年之后明亮的条痕在新拍的图像中亮相，促使马林空间科学系统公司的迈克尔·马林及同事得出结论：条痕可能是火星上冒出的地下水造成的。 |
| But Jon Pelletier, a geoscientist at the University of Arizona (UA) in Tucson, and his team now say "pure liquid water" is unlikely to have made such formations in the Centauri Montes region of Mars. |
但是，目前图森亚利桑那大学的地球学家乔恩·佩尔蒂埃及同事称：“纯净的液态水”不大可能在火星的半人马高地形成这样的构造。 |
| "The dry granular case was the winner," Pelletier said, referring to a dusty mode of creation. "I was surprised. I started off thinking we were going to prove it's liquid water." |
提到构造中尘埃的类型，佩尔蒂埃说：“那里的情况更有可能是干燥的颗粒状物质。我感到很惊讶：开始研究时我认为我们能够证实那是液态水！” |
| Pelletier and his colleagues' findings, which are based on Mars Reconnaissance Orbiter images taken by High Resolution Imaging Science Experiment (HiRISE) camera, will be detailed in the March issue of the journal Geology. |
佩尔蒂埃及同事根据火星侦探卫星上高分辨率科学实验成像仪（HiRISE）所拍下的图像做出了这项发现，该发现将详细地记录在3月份出版的《地质学》杂志上。 |
| Since 2006, HiRISE has provided the most detailed images of Mars ever taken from orbit, giving Pelletier a chance to offer a second opinion on the existence of liquid water that might still support life beneath the Red Planet's surface. |
自从2006年以来，HiRISE从轨道卫星上提供了最为精细的图像，使佩尔蒂埃能够对于液态水是否存在的问题提出新见解。但液态水仍然有可能存在于这颗红色行星的表面以下，维持着生命的存在。 |
| "What we'd hoped to do was rule out the dry flow model," said Alfred McEwen, a UA professor and leader of the HiRISE team. "But that didn't happen." |
“我们本希望能够将干燥物质流动的模拟情况排除在外，”亚利桑那大学教授、HiRISE研究小组组长阿尔弗雷德·麦克尤恩说，“但就是没法排除！” |
| Although the new study doesn't rule out a watery creation of the bright streaks, Pelletier and McEwen said a bone-dry avalanche of dust and rocks is the most likely culprit. Their conclusions stem from work with 3-D maps created with HiRISE image data. |
佩尔蒂埃和麦克尤恩称，尽管这项研究并不排除明亮的条痕是由水流造成的，但是极为干燥的尘埃和岩石顺坡而下最有可能是造成条痕的原因。他们的结论来自于对三维地图的研究，这些三维地图是利用HiRISE所拍下的图像创造的。 |
| "This is the first time that anyone has applied numerical computer models to the bright deposits in gullies on Mars," Pelletier said. When he compared the bright deposit and its HiRISE image to the predictions made by the model, the dry avalanche model was a better fit. |
佩尔蒂埃指出：“这是首次将数值计算机模拟技术运用于火星沟壑中明亮的沉积层上。”他将明亮的沉积层及其HiRISE成像跟计算机模拟所做的预测进行对比之后，确定顺坡而下的干燥物质模型更符合实际情况。 |
| "There are other ways of getting deposits that look just like this one that do not require water," Pelletier said. |
佩尔蒂埃说：“还有其他的办法，可以不用水就能得到恰似这样的沉积层。” |
