Dark Ice on a Hot Planet
by Govert Schilling 胡德良 译
| NANTES, FRANCE—Despite basking in the sun's fiery glow, tiny Mercury, the innermost planet in our solar system, is probably home to extensive ice fields. Twenty years ago, radar observations from Earth revealed small, highly reflective areas close to Mercury's poles, suggesting the presence of ice. Now, NASA's MESSENGER spacecraft, which has orbited Mercury since March, has confirmed that these radar-bright patches neatly coincide with deep crater floors near the poles that never receive any sunlight at all. This new color-coded photo mosaic of Mercury's south polar region, presented here today at a joint meeting of the European Planetary Science Congress and the Division for Planetary Sciences of the American Astronomical Society, shows these "freezer" areas as dark blotches. According to MESSENGER instrument scientist Nancy Chabot of the Johns Hopkins University's Applied Physics Laboratory in Laurel, Maryland, a full one-fifth of the region within 200 kilometers of Mercury's south pole is in permanent shadow. "It's all consistent with there being water ice," she says. | 法国南特消息：尽管沐浴在太阳的火热光芒中，我们太阳系最里面的小型行星——水星很可能存在广泛的冰原。二十年前，地球上的雷达观测数据显示，水星的极地拥有小块的高反射区，表明有冰存在。现在，NASA的“信使”号太空船自从三月份开始就一直在水星的轨道上运行，该太空船证实了雷达观测到的亮区正好是水星极地深深的陨石坑坑底，那里从来都没有接受到阳光。今天，一张水星南极区的新拍颜色编码拼图提交到欧洲行星科学大会和美国天文学会行星科学部在这里举行的联合会议上，该图把这些冷冻区显示为黑块。马里兰州劳雷尔市约翰霍普金斯大学应用物理实验室研究“信使”号仪器的科学家南希·沙博说，在水星南极方圆200公里的范围内，整整五分之一的区域永久地处于阴影中。“这一切一致地表明：那里存在水冰，”她说。 |
译自：美国《科学》杂志网站（5 October 2011, 4:26 PM）
原著：Govert Schilling
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