Venus spins so slowly that one day there lasts longer than its whole year.

The longer version

Venus rotates so slowly that a single turn on its axis takes longer than one trip around the Sun. Its spin is also retrograde, meaning it turns opposite to most planets, so an observer on the surface would see the Sun rise in the west.

Dense atmosphere and thick cloud make the surface dark and uniform, and winds high above move much faster than the ground below. Scientists suspect a massive early impact or strong atmospheric tides slowed the planet down, but the exact history remains uncertain. Either way, the outcome is a planet where the Sun crawls across the sky and surface temperature barely changes between noon and midnight.

Where this entry sits

The night sky looks calm, yet almost everything up there is moving, burning, or slowly changing. These facts cover planets, stars, the Moon, gravity, black holes, comets, and the story of how people began exploring beyond Earth. The full list sits on the Space and Sky page, where every entry is listed in order.