如何登陆火星？极其小心！

Earth’s moon is shown in full phase. At the top of the frame, appearing much smaller, is the more distant planet Mars. Please see the explanation for more detailed information.
图中显示的是地球的卫星，正处于满月。画面上方是更远的火星，看起来小得多。有关更多详细信息，请参阅说明。