# Invariant

### From Conservapedia

**Invariant** in relation to any physical quantity means that this value is independent of reference frame in which one observes the given quantity.

E.g. invariant mass denoted in physics by *m* is for a given particle independent of its reference frame in which this particle is observed. This independence is achieved by dividing the relativistic mass (the measure of inertia of the particle) by γ factor.

So if velocity of a particle is *v* one gets invariant mass of the particle by dividing relativistic mass of the particle *M* by γ factor as in *m* = *M* / γ, where γ^{2} = 1 / (1 − *v*^{2} / *c*^{2}), *v* is velocity of the observed particle, and *c* is speed of light in vacuum.