Can a massless particle have no momentum?

For a massless particle energy and momentum are the same. If such a particle had no momentum then it would also have no energy, and that's equivalent to having nothing, no particle. read more

For a massless particle energy and momentum are the same. If such a particle had no momentum then it would also have no energy, and that's equivalent to having nothing, no particle. So no, you can't have a massless particle at rest/with no spatial momentum. read more

This is because the momentum of a massless particle depends only on frequency and direction, while the momentum of low speed massive objects depends on mass, speed, and direction. Massless particles move in straight lines in spacetime, called geodesics, and gravitational lensing relies on spacetime curvature. read more