Forgive that to many here this will sound like a dumb question. I have searched and searched and failed to find an answer. Give the constant creation/annihilation of all forms of particles in ZPE, it seems likely to me that some among them would collide with each other before either had a chance to annihilate. When such collision occurs, does any energy get transferred to the "real" world and not get annihilated? Has any calculation ever been made as to how often such collisions are likely to occur? Thanks for your help.