Meanwhile the southern hemisphere will face shorter and shorter days, beginning its descent into winter.

Callisto's rotation is tidally locked to its revolution around Jupiter, so that the same hemisphere always faces inward; Jupiter appears to stand still in Callisto's sky.

Like its fellow Galilean satellites, Europa is tidally locked to Jupiter, with one hemisphere of the satellite constantly facing the planet.

One hemisphere of the moon always faces Earth, as the moon revolves around Earth.

Because Ariel, like Uranus, orbits the Sun almost on its side relative to its rotation, its northern and southern hemispheres face either directly towards or directly away from the Sun at the solstices.

As Earth was now far back toward the sun, its darkened hemisphere faced Discovery, and on the central display screen the planet appeared as a dazzling silver crescent, like another Venus.

During May, June and July, the northern hemisphere is exposed to more direct sunlight because the hemisphere faces the sun.

The computer translated the numbers into a location on the planetary grid and, since the spot was on the hemisphere of Tregania facing the ship, it locked its telescopic cameras on the site.

While the moons exhibit rotation, they do so in concert with their orbits so that one hemisphere always faces outward, away from the center of the system.

The wide hemisphere faces the sun.