G. Bruce Mainland and Bernard Mulligan
Ohio State University
Physicists have speculated about the properties of the quantum vacuum for at least 85 years; however, only recently have they understood the quantum vacuum sufficiently well to begin making predictions that agree with experiments. Specifically, using Maxwell’s equations to describe the interaction of vacuum fluctuations with the electromagnetic field, it has been possible to calculate the Coulomb constant, the speed of light in the vacuum, and the fine structure constant. Physicists are now also beginning to successfully address problems in cosmology based on properties of the quantum vacuum. The term "vacuum catastrophe" refers to the fact that the value of the vacuum energy density predicted in the 1970's is approximately 120 orders of magnitude larger than the observed energy density of the universe. Using properties of the quantum vacuum and well-established physics, it is possible to demonstrate that the huge vacuum energy cannot exert a force on normal matter; accordingly, vacuum energy does not contribute to the observed energy density of the universe. In a similar vein, the cosmological constant, which plays a central role in the accelerating expansion of the uni- verse, can be shown to be unaffected by the huge vacuum energy density.