- #1
kthouz
- 193
- 0
How can one calculate the center of mass of a system made of two photons? I know that they have zero rest mass so the first intuition is to say that they do not have any center of mass. However, I read about something called center of momentum which is defined as a frame in which a moving particle is at rest. So, if it is possible to have a center of momentum of a system of two photons, how can the center of mass of this system be defined?