"Rotate about" vs. "rotate around" [closed]

About and around are synonymous in this context; they are both valid and mean the same thing.

Ngrams shows us that rotate has been more commonly used with about, though in later years the two options seem to have become more equivalent in terms of popularity:

I'm not really sure if this is a well-defined and widely accepted difference, but to me, "Rotate about" implies that the object is spinning in place (i.e. the defined axis passes through the center of the object in question, or at least through some internal point of the object), while "rotate around" implies that the object is orbiting an external point.