Howdy. It has become clear to me that translational motion is not taken into account in general relativity because it is subjective, and that rotational motion is taken into account in GR in places such as the Kerr Metric. What makes rotational motion so absolute? Couldn't an observer's measurement of the rotational frequency of an object be different from another observer's measurement, (making rotational frequency subjective)? Thank you all in advance for the time you put into this. It is appreciated.