About the Gödel universe

A hypothetical universe, derived from the equations of the general theory of relativity, that admits time travel into the past; it is infinite, static (not expanding), rotating, with non-zero cosmological constant. Kurt Gödel, best known for his incompleteness theorem and one of the first scientists to be intrigued by the possible physical basis of time travel, theorized the existence of such a universe in a brief paper written in 1949 for a Festschrift to honor his friend and Princeton neighbor Albert Einstein. Although largely ignored, Gödel’s paper raised the question: if one can travel through time, how can time as we know it exist in these other universes, since the past is always present? Gödel added a philosophical argument that demonstrates, by what have become known as Gödel’s lights, that as a consequence, time does not exist in our world either. ((http://www.daviddarling.info/encyclopedia/G/Godel_universe.html))