rest mass

Objects without a rest mass, such as photons, also carry momentum.

It destroys the old idea that you cannot create more energy at a point than the rest mass of the matter residing there.

They're elementary particles, with no charge, and a tiny rest mass.

On the other hand, in his first paper on (1905) he treated m as what would now be called the rest mass.

That figure is almost twice the actual rest mass in the neighborhood.

Clearly it must have a rest mass of zero, like a neutrino.

All matter, such as any object, has some rest mass.

A body in space has a rest mass which determines its gravitational field.

In fact, since photons have zero rest mass, all their energy is kinetic.

Because the wave is always moving and never actually at rest, it does not have a rest mass.