Which of the following planets rotates in the clockwise direction?

Concept

Every planet spins about its own axis. The spin is called prograde (direct) when, viewed from above the Sun's north pole, it turns counter-clockwise (west to east) — this is the same sense in which the planets orbit the Sun and is the norm in the Solar System. The spin is called retrograde when it turns the opposite way, i.e. clockwise (east to west).

Application

Among the four planets offered, the one with retrograde (clockwise) rotation is Venus. Because of this backward spin, on Venus the Sun rises in the west and sets in the east — opposite to what we experience on Earth. Venus also rotates extremely slowly, taking about 243 Earth-days for a single spin.

Contrast

The other three planets all spin in the usual prograde (counter-clockwise) sense, the same direction as their orbital motion:

• Mars spins counter-clockwise (prograde), like Earth, with a day of roughly 24.6 hours.

• Jupiter spins counter-clockwise (prograde) and is in fact the fastest-rotating planet, with a day under 10 hours.

• Saturn spins counter-clockwise (prograde), with a day of about 10.7 hours.

Note: In the full Solar System, Uranus is also a retrograde rotator (it spins on its side), but it is not one of the options here. Among the choices given, Venus is the planet that rotates clockwise.