The fact that space has three dimensions would seem to be one of the most obvious and indisputable features of our world. Ever since Einstein proposed his theory of general relativity, however, it… Expand

We examine models in which the dark energy density increases with time (so that the equation-of-state parameter w satisfies w < -1), but w approaches -1 asymptotically, such that there is no future… Expand

If we assume that the cosmic energy density will remain constant or strictly increase in the future, then the possible fates for the universe can be divided into four categories based on the time… Expand

It is proposed that the highest energy $\sim 10^{20}$eV cosmic ray primaries are protons, decay products of a long-lived progenitor whose high kinetic energy arises from decay of a distant… Expand