What is the contribution of virtual particles to the mass of the universe?
Virtual particles are required in order to understand a variety of subtle processes in physics. The problem is that, given the current state-of-the-art in producing a truly comprehensive ‘Theory of Everything’ there seems to be no good idea how nature avoids having the energy of the physical vacuum contribute mass/energy to the total energy budget of the universe. This weight is determined by the size of the so-called cosmological constant. Astronomers have, for decades, been saying that their observations indicate that the cosmological constant, if at all present, contributes no more than about the same mass as the mass in all matter in the universe. Physicists calculating the same factor from their various versions of the Theory of Everything, get predictions that are 10^120 larger than the astronomical limits! Unless they fine-tune their theories very carefully, it is hard to avoid this catastrophe, so somehow, nature manages to set this number to a very small number with an accurac
