Richard Feynman writes, on page 97 of his primer of quantum electrodynamics, QED: The Strange Theory of Light and Matter, about the interaction of a photon and an electron. He writes: "One way this event can happen is: a photon is absorbed by an electron, the electron continues on a bit, and a new photon comes out." FIRST QUESTION: When Prof. Feynman says "continues on a bit," what sort of time scale is involved? Is it on the order of 10-30 to 10-15 second, or can it also be whole seconds, minutes, years or even eons? I take it that an electron in free space cannot interact with a photon because there is no way an electron can store a photon's energy. But for an electron in an atom, the energy of the photon can be stored in the atom, i.e., with the electron being pushed a little farther from the nucleus. SECOND QUESTION: What drives, provokes, or stimulates the process by which "a new photon comes out"? I'm not a physicist, just an interested layman. Thanks for any guidance.