if perpetual motion is impossible, why/how do planets orbit and spin continually?

Question

if perpetual motion is impossible, why/how do planets orbit and spin continually?

In: Physics

Answer 1

The length of time a planet spins is finite, not continuous. They spin due to the gravitational effects of the sun they orbit. The sun has gravitational energy due to its size and the energy inside it. When it runs out, so does it’s effect on the planets. I think.