Matter is defined as that which 1) has mass and 2) has volume or takes up space. Mass is an intrinsic property whose base SI unit is the kilogram (kg).

But since dark matter has mass, its presence is inferred based on the gravitational pull it exerts on regular matter. But it's more complicated than that. In the 1920s, ...

If each photon had just a tiny bit of mass, it could upend the theory of dark matter. Mass Effect. For many years, astrophysicists have theorized that an invisible material they call "dark matter ...

Dark matter is one of nature's most confounding mysteries. It keeps particle physicists up at night and cosmologists glued to ...

In any case, if our understanding of the early Universe is correct, axions have a mass somewhere between 50 micro-electronVolts and 1,500 μeV. That's still a pretty large range, but it definitely ...

According to the team’s results, dark matter should mass somewhere between 55 grams (1.9 oz), which is as much as a tennis ball, and 10 24 grams, which is around the mass of the dwarf planet Ceres.

A stock image of a galaxy. A physicist has a new theory that could lessen the need for dark matter to exist. Getty Images/Ellen11. Lieu suggests that the additional gravity needed to hold a galaxy ...

For ordinary matter, momentum is given by the formula P = mv, where P is momentum, m is mass, and v is velocity. Even tiny amounts of matter can have vast amounts of momentum if the matter is ...

But since dark matter has mass, its presence is inferred based on the gravitational pull it exerts on regular matter. But it's more complicated than that. In the 1920s, ...