Energy=mass always. Theoretically you can make a black hole out of light, or you can turn that photon energy into inertial mass by running light in a closed loop.
No lol, there’s a momentum component to that equation which is just conveniently 0 for massive objects at rest, photons don’t have a rest reference frame and are governed by E=pc.
They have momentum, not mass, in relativistic physics you need something more complex than p=mv to describe momentum.
Energy=mass always. Theoretically you can make a black hole out of light, or you can turn that photon energy into inertial mass by running light in a closed loop.
No lol, there’s a momentum component to that equation which is just conveniently 0 for massive objects at rest, photons don’t have a rest reference frame and are governed by E=pc.