Venus Spins Backwards Slower Than It Orbits

Venus does something almost no other planet does: it rotates backwards relative to its orbital direction. But there's something even stranger. A single day on Venus, measured from sunrise to sunrise, lasts 243 Earth days. Its year, the time it takes to orbit the sun, is only 225 Earth days. This means Venus completes its journey around the sun faster than it completes a single rotation on its axis. This bizarre situation happens because Venus rotates so slowly and in the opposite direction to most planets. The sun appears to rise in the west and set in the east from Venus's surface. If you stood on Venus and watched carefully, you would see the sun move across the sky more slowly than you'd experience the passage of seasons. Winter would come and go while you waited for noon to arrive. Scientists believe a massive collision early in Venus's history knocked it sideways, reversing its spin and slowing it dramatically. Over billions of years, the planet's thick atmosphere and the sun's gravitational pull may have continued to brake its rotation. Today, Venus rotates so sluggishly that its atmosphere actually moves faster than the planet itself, completing a full circuit every four Earth days.