How is matter different from mass? These and other questions about the deepest levels of physics, answered inside.

Perhaps one of the most surprising discoveries of the 20th century was that this ordinary, or baryonic, matter makes up less than 5 percent of the mass of the universe. The rest of the universe ...

Mass balance ensures that the carbon formerly ... individual elements can vary a great deal between nonliving and living matter (Figure 5). Life on Earth depends on the recycling of essential ...

This dark matter makes up most of the mass in the universe, far outweighing the amount of luminous matter. The identity of dark matter remains a mystery, as experiments designed to detect a stray ...

An international team of researchers has found dark matter dominating the halos of two supermassive black holes in galaxies ...

A piece of iron with the same dimensions as a piece of aluminium will be heavier because the atoms are more closely packed and each iron atom has much more mass than each aluminium atom.

Scientists have taken a bold step toward understanding dark matter, the invisible force shaping the cosmos. Using atomic ...