Question

Why does Venus revolve from west to east?

Answer 1

A planet's axial tilt is a measure of whether the planet is in prograde (the natural direction of rotation of most bodies in our solar system) or retrograde (the opposite, ie, from East to West) rotation. The tilt angle is measured relative to the orbital plane of a planet. A tilt between 1 to 90 degrees is considered prograde rotation (Earth's tilt is 23 degrees, in prograde rotation), a tilt of 90 degrees is considered perpendicular, and neither prograde or retrograde. However, a tilt of anything greater than 90 degrees is considered retrograde rotation. Uranus's axial tilt is almost 98 degrees, and Venus's tilt is 177 degrees. So they're both considered to have retrograde rotation.

Currently, the most popular theory states that Venus did indeed rotate in the same direction as the rest of the planets. But at some point of time, something caused the planet to flip 180 degrees around its axis. This could have been a collision of a large body at an angle that got absorbed into Venus, or due to some unknown cause. So it continued spinning in the same direction but flipped itself over. So the rotation looks reversed to us.

Some scientists also believe that there could also have been major storms on one side of the surface of Venus that could have altered the direction of rotation.

The newest theory that French astronomers have proposed is that Venus's rotation kept slowing down and finally hit a stop, and then the planet started spinning in the opposite direction.