Even the hot and cracked surface of Venus has rolling hills. Although never actually photographed from up-close, images of the Venusian surface like that shown above have been constructed in recent years by digitally merging distant photographs with height-sensitive radar. Isolated above is a 100-kilometer wide swath inside a volcanic region known as Yavine Corona.

In 1930, tiny, icy world Pluto was discovered orbiting in the distant solar system. In 1978, its relatively large companion Charon was detected by ground-based observations. This year, the Hubble Space Telescope may well have detected two further members of the Pluto system.

Why is Umbriel so dark? This dark moon reflects only half the light of other Uranus' moons such as Ariel. And what is that bright ring at the top? Unfortunately, nobody yet knows. These questions presented themselves when Voyager 2 passed this satellite of Uranus in January 1986.