PX262 - G2b - spin

spin is the intrinsic angular momentum associated with a particle

• intrinsic refers to a fundamental property, like mass or charge

spin is often analogised using the angular momenta for the motion of the earth:

• orbital angular momentum is associated with its motion around the earth
• spin angular momentum is associated with it spinning in its axis

however, articles do not actually spin like the earth, as this would contradict special relativity by speeds faster than $c$

Dirac showed that quantum mechanics and relativity can be made consistent only if electron is assumed to be a point particle that possesses spin