Recent content by vivitar02

I have read so much, please put me straight on "photon interaction" 1. My photon hits matter. 2. It interacts with the atoms of that matter. 3. The electron (say) energy level transition (High->Low) spawns photon(s) of lower energy levels? 4. My photon is now other photon(s) but...

1. They decay to lower energies, but remain as photons ? 2. As it propogates through matter (mass?), is the photon's energy changing ? 3. Sorry, when I say mass, is that the same as referring to massive particles, i.e particles with a non-zero rest mass? Sorry, I'm fascinated by the...

If electron-positron annihilation creates a photon, with "mass-energy", how long will the photon live for? It will travel at the speed of light until when?