system
Given the following post, respond as if you're commenting on Reddit:
human
Will an object rotating in a vacuum which has no contact with another external object, rotate infinitely or will it gradually lose its speed?

Until yesterday, I thought if there is no friction force with a rotating object, it will never lose its spin, but I read somewhere that even under such conditions, the object will gradually slow down (but the reason was not specified). So, which force slows the rotation speed?

Moreover, does the Earth lose its average (sidereal) rotation speed in time?
gpt
An asymmetrical (around the axis) rotating object will radiate gravitational waves (symmetrical ones will only drag space without radiating), but that would take billions of years to have an effect on most objects.