科学家揭开"火星上是否有水"之迷

　　The water may not necessarily be flowing over the ground, according to the scientists.

　　科学家们认为，水并不一定是在地面以上所流动的。

　　Some clues suggest it could be buried but affecting the surface to make it appear dark.

　　有证据表明，水流有可能存在于地表之下，并且使得地表面的颜色变深。

　　Saltiness lowers the temperature at which water freezes. This means seasonal salty liquid water could exist in mid-latitude regions of Mars, despite the chilliness of the planet's ‘warm’ season.

　　盐分会使得水凝结成冰的温度降低，这也就意味着，尽管在火星上所谓“温暖”的时期里气温也低得吓人，但在这个星球的中纬度地区，可能有含盐的液态水季节性的存在。

　　The lines are between around half a metre to five metres wide but extend for hundreds of metres.

　　这些线条的宽度介于半米到五米之间，有的甚至有几百米。

　　In some of the sites scientists identified more than 1,000 individual flows reaching down steep slopes such as the rims of impact craters.

　　在火星的某些区域之内，科学家发现了超过了1000条独立了河流，它们从陡峭的山坡之上流到了陨石坑的边缘。

　　University of Arizona student Lujendra Ojha, who was the first to spot the features after identifying subtle seasonal changes in the orbiter images, said: ‘I was baffled when I first saw those features ... we soon realised they were different from slope streaks that had been observed before.

　　亚利桑那州大学的学生Lujendra Ojha是第一个人在卫星图形图片上发现了这一季节性变化的情况，他说：“当我看到了这些情况时百思不得其解，很快地我们就意识到，这与之前所观察到的山坡的线条是不同的。”

　　‘These were highly seasonal, and we observed some of them had grown by more than 200 metres in a matter of just two Earth months.’

　　“这些图像的季节性非常之明显，我们观察到了其中的一些在两个月的时间之内，从1米的宽度拓展到超过了200米。”

　　The lines appear to lengthen and darken on rocky equator-facing slopes from late spring to early autumn.

　　在春季到初秋的时间里，这些线条长度会变长，在赤道周围的斜坡上所显现的颜色也会变得更深。

　　They therefore seem to favour warm areas and times, suggesting that they consist of volatile material.

　　看起来它们在温暖的区域和时节更为明显，这表明其可能是挥发性物质。

　　However the sites are too warm for frozen carbon dioxide, and in some regions too cold for pure, non-salty water.

　　然而这些区域由于多余温暖而不可能存在冻结的二氧化碳，然而要有纯净的不含盐分的水出现的话，这里的气温有显得太低。