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.

Matter is what makes up the universe, but what makes up matter? This question has long been tricky for those who think about it - especially for the physicists. Reflecting recent trends in physics, my colleague Jeffrey Eischen and I have described an updated way to think about matter.