Planets’ Rotation and Revolution

How do our planets rotate and revolve?

There is a difference between an object that is ‘rotating‘ and one that is ‘revolving‘: for example, planets rotate on their axes, but revolve around the Sun in their orbits. On that score, seen from above its North Pole, the Earth both rotates and revolves in an anti-clockwise direction.

As it turns out, almost everything in the Solar System revolves and rotates in anti-clockwise direction. Even the Sun spins on its axis in anti-clockwise motion, taking 25.4 days to complete one rotation (but slightly more at its poles).

There are, however, a few exceptions to the ‘everything goes anti-clockwise’ rule: Venus, Uranus and Pluto have ‘clockwise’ motion.

Why doesn’t the rotation slow down?

Well, actually, it is slowing down, but very slowly. The moon’s rotation, for instance, has already slowed to match its period of revolution around the Earth. Owing to tidal friction, the same process is taking place throughout the Solar System. however, there is so much rotational energy stored in the Solar Syatem that the spin-down period is measured in tens of billions of years, so there is no need to panic yet.

(pgs. 140-141, “Why is Uranus Upside Down?” by Fred Watson)


One thought on “Planets’ Rotation and Revolution

Leave a Reply

Please log in using one of these methods to post your comment: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s