i guess casimir effect speaks of particle pairs formin n annihilating all the time at pico scales. what i did not understand is that how is energy conserved here? everytime particle pairs are produced, some energy is "borrowed". fine. but when they annihilate, shouldnt photons be emitted n energy increased? same thing in hawking radiation also where he speaks of hawking radiation. particle antiparticle pairs are produced, one of which enters the black hole n causes annihilation while the other adds to the mass of the universe. plz enlighten me Please Register or Log in to view the hidden image!