What makes the earth rotate?

1 Answer
Oct 3, 2016

Residual angular momentum from the time of its formation.


There's basically little to slow it down, though it is very gradually slowing in its rotation.

Whatever processes formed the Earth, whether collisions or accretions, there would be some residual angular momentum.

Once the surrounding detritus and gas was mostly gone or included, there was little to slow any remaining rotation.