Physicists find dark matter: It's everywhere

A group of Japanese physicists has revealed where dark matter is — though not what it is — for the first time. As it turns out, the mysterious substance is almost everywhere, drooping throughout intergalactic space to form an all-encompassing web of matter.

Dark matter is invisible: It doesn't interact with light, so astronomers cannot actually see it. So far, it has only been observed indirectly by way of the gravitational force it exerts on ordinary, visible matter. On the basis of this gravitational interaction, physicists have inferred that dark matter constitutes 22 percent of the matter-energy content of the universe, while ordinary detectable matter constitutes just 4.5 percent.