> The shells in my paper consist of a thin inner layer of positive mass and a thin outer layer of negative mass; the total mass of both layers—which is all one

> The shells in my paper consist of a thin inner layer of positive mass and a thin outer layer of negative mass; the total mass of both layers—which is all one could measure, mass-wise—is exactly zero, but when a star lies on this shell it experiences a large gravitational force pulling it towards the center of the shell Is "negative mass" a real thing in Physics or just some wild theory?