My "Day", your "Night"

Though Earthlings will be able to get a good look at Mars during close approach, NASA's 2 Rovers on Mars will not be able to see Earth. That's because at the moment, Earth is on the daytime side of Mars. As shown in the top half of this artist's rendering, when it's nighttime on Earth, it's daytime on Mars. After Earth passes Mars, the Rovers will be able to see the sunlit side of Earth again just before dawn. The bottom half of this illustration shows what the Rovers would see if they looked toward Earth.