A study from 2013 showed that the rotation of the inner core of the Earth is opposite to the rotation of the crust.
In any circumstances this would result in large frictional forces between these rotating bodies.
It is always said that the Earth spins because of the spin it had when it was born and that no force or energy is needed for the Earth to keep spinning. There would only be a frictional force because of the tidal effect of the Moon.
But now we know that different parts of the Earth spin in opposite directions, causing substantial friction inside the planet, the idea of a non-powered endless spinning Earth seems to be wrong.
And it implies that the earth gets energy from an unknown source that causes it to keep spinning.
The rotational speed of the Earth's crust is slowing down in time because of the tidal effect of the Moon. But taking into account the friction between the crust and the inner core, the rotational speed of the Earth's crust would slow down considerably in a century or less, if there would not be a force that causes the Earth to spin.
Can it be that the energy from the Sun does not only provide us with solar energy and heat, but also causes the Earth and the other planets in the Solar system to keep spinning?
What do you think?