文章掠影：
火星表面的这些东西看上去像树木，但它们不是。这些在布满薄霜的粉红沙丘挤成一簇一簇的暗棕色条状物是“火星勘探轨道飞行器”拍下来的。
英文原文：
They might look like trees on Mars, but they’re not. Groups of dark brown streaks have been photographed by the Mars Reconnaissance Orbiter on melting pinkish sand dunes covered with light frost. The above image was taken in 2008 April near the North Pole of Mars. At that time, dark sand on the interior of Martian sand dunes became more and more visible as the spring Sun melted the lighter carbon dioxide ice. When occurring near the top of a dune, dark sand may cascade down the dune leaving dark surface streaks -- streaks that might appear at first to be trees standing in front of the lighter regions, but cast no shadows. Objects about 25 centimeters across are resolved on this image spanning about one kilometer. Close ups of some parts of this image show billowing plumes indicating that the sand slides were occurring even when the image was being taken.
参考译文：
火星表面的这些东西看上去像树木，但它们不是。这些在布满薄霜的粉红沙丘挤成一簇一簇的暗棕色条状物是“火星勘探轨道飞行器”拍下来的。这张照片摄于 2008年4月，地点接近火星北极。火星沙丘内部的暗沙，随着春日的阳光融化较薄的干冰而逐渐清晰可见。如果发生在一个沙丘的顶部，暗沙有可能从上面滑下来，露出深色的条状物——这些条状物可能开始看上去像矗立在明亮区域前面的树木，但是没有阴影。图片上宽度约25公分的物体分解后绵延约一公里。照片某些部位的特写显示出缭缭烟雾，表明即使在拍摄照片的时候，沙子还在流动中
责任编辑：sealion1986
