[unhba]

Thanks for this explanation. If I understand correctly then, the moon requires some centripetal force in order not to dissipate due to its rotation whereas e.g. my head or the Eiffel Tower do not because they are not subject to absolute rotation.

[card_zero]

They're rotating too.

If you rotate as part of some larger rotating thing then you still rotate. (You also move around.) It's all absolute.

[omnicognate]

Indeed. The Eiffel tower and your head do both have some (extremely small) centripetal force compensating for their rotation along with the earth.

(You can break that down in different ways, i.e. use various choices of generalised coordinates to describe it, so exactly what constitutes "centripetal", "centrifugal", "gravitational", "tidal", etc. forces depends on that. I'm being pretty vague in how I decribe it. Regardless, rotation is absolute, or in other words the equations of physics take a different form in a rotating frame of reference than in a non-rotating one.)

[adastra22]

Why is the Eiffel Tower not rotating?

[omnicognate]

It is.