火卫一在火星上
(原标题: Phobos over Mars)
2023-07-31
浏览次数: 17
为什么火卫一这么暗？火卫一是火星两颗卫星中最大、最里面的一颗，也是整个太阳系中最暗的卫星。它不寻常的轨道和颜色表明，它可能是一颗被捕获的小行星，由冰和深色岩石的混合物组成。这张火卫一在火星边缘的彩色特色照片是由欧洲航天局的火星快车号机器人航天器于2021年底拍摄的，该航天器目前正在绕火星运行。火卫一是一颗布满陨石坑的贫瘠卫星，其最大的陨石坑位于远侧。从这样的图像来看，火卫一被大约一米厚的松散尘埃所覆盖。火卫一的轨道离火星很近，从某些地方可以看到它每天升起和落下两次，而从其他地方根本看不见它。火卫一围绕火星的轨道在不断衰减——它可能会在大约5000万年后破裂，碎片撞向火星表面。你的天空惊喜：APOD在你的生日上展示了什么照片？(1995后)
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Why is Phobos so dark? Phobos, the largest and innermost of the two Martian moons, is the darkest moon in the entire Solar System. Its unusual orbit and color indicate that it may be a captured asteroid composed of a mixture of ice and dark rock. The featured assigned-color picture of Phobos near the edge of Mars was captured in late 2021 by ESA's robot spacecraft Mars Express, currently orbiting Mars. Phobos is a heavily cratered and barren moon, with its largest crater located on the far side. From images like this, Phobos has been determined to be covered by perhaps a meter of loose dust. Phobos orbits so close to Mars that from some places it would appear to rise and set twice a day, while from other places it would not be visible at all. Phobos' orbit around Mars is continually decaying -- it will likely break up with pieces crashing to the Martian surface in about 50 million years. Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)