system
Given the following post, respond as if you're commenting on Reddit:
human
What effect does a spinning object have on space time, if any?

A stationary object curves spacetime, but does the presence of angular momentum have any effect on that curvature?
gpt
Yes, a spinning source of mass creates a *frame dragging* effect around it. For some objects, there may even be a so-called *ergosphere* around the object, which describes a region in which all particles must actually co-rotate with the gravitating mass. That is, there is no such thing as a stationary object in this region according to a faraway observer. 

Black holes with non-zero angular momentum, for instance, exhibit these features, including an ergosphere.