When we do a careful accounting of all of the ordinary matter that can respond to electromagnetism (matter made of protons, neutrons, electrons, etc. either making light or blocking it), we find that the ordinary matter makes up less than 20% of the gravity of the overall matter and the remaining gravity seems to be from exotic particles predicted by particle theory but not yet discovered in our particle experiments such as at Fermilab and the Large Hadron Collider. The mass ratio of exotic particles to ordinary matter is five to one. Stronger evidence for the five-to-one mass ratio comes from looking at relics of the early universe as explained in the cosmology chapter.