A new paper discusses how light interacts with theoretical objects called "topological solitons" - kinks in the fabric of space-time that look just like black holes.

KB: We asked ourselves, "what obliquity, what misalignment would Planet Nine induce in the solar system?" because it must induce some. We know that Planet Nine's orbit in inclined. As a result, when Planet Nine torques the rest of the solar system, the two sort of act as two precessing tops.