Venus Rotates Backwards

While most planets spin counter-clockwise, a relic of the swirling nebula that formed our solar system, Venus stands apart. Its peculiar rotation wasn't confirmed until the 1960s, when radar was able to penetrate its thick, perpetual cloud cover. These observations revealed the surprising truth: Venus spins clockwise, and does so with incredible slowness. This backward movement, known as retrograde rotation, means that on Venus, the sun would appear to rise in the west and set in the east.

Scientists have two main theories to explain this unusual behavior. One hypothesis points to a colossal impact during the solar system's chaotic youth. It's possible that a planet-sized object slammed into Venus, altering its spin in a way similar to how a collision is thought to have knocked Uranus on its side. An alternative theory suggests a more gradual process involving Venus's own extreme atmosphere, which is about 90 times as massive as Earth's.

This second theory proposes that the sun's powerful gravity dragged on the dense Venusian atmosphere, creating strong atmospheric tides. Over billions of years, these tidal forces, along with friction between the planet's core and mantle, could have acted like a brake, slowing the planet's original rotation to a stop and then causing it to slowly reverse. The planet's powerful atmosphere continues to affect its rotation, dragging along the surface and slowing its spin.