Question: How does the world spin?

Bruce Alexander answered on 18 Jun 2012:

When the earth first formed, many, many years ago, it was the result of lots of collisions between gas molecules and dust particles, and a whole load of little bits and pieces coming together to form larger pieces. As a result of these collisions, the larger particles started to move, which is where the spin originally came from. As there were more and more collisions as the size of the particles became larger until the planet gradually became the size it is today. All during this time, the world was continually spinning as there was nothing that hit the earth that was large enough to stop the rotation.

This is why the world spins. There are other things that effect the speed at which we spin, such as gravitational forces (such as those coming from nearby planets, the sun and the moon) and tidal forces. The oceans slosh around the surface of the planet and are not evenly spread around – this can have quite an effect on the spinning.