But what's an atom made of? What is matter, really? Matter is defined as that which 1) has mass and 2) has volume or takes up ...

JAMES: Because mass is about the amount of matter, whereas weight is a force and is the heaviness due to gravity. ELLIE: Exactly. So let me tell you about the equation you need to calculate the ...

However, scientists don’t see enough visible mass in many galaxies in the universe, yet gravity keeps such galaxies intact.

Scientists have uncovered new details about how mass is distributed inside tiny particles called hadrons, such as protons, ...

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.

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 ...

Although dark matter makes up about 85% of all mass in the Universe, it's extremely difficult to detect and defies a ready description. But dark matter influences the large scale structure of ...