Alan Guth

Happy birthday Alan Guth! Born in 1947 in New Brunswick, New Jersey, Guth studied physics at Princeton and Columbia universities. He originally set out to become a particle theorist, but a lecture by Robert Dicke on the so-called flatness problem in cosmology inspired him to seek a solution. Invoking physics from grand unification theories, Guth proposed in 1981 a way to solve both the flatness problem (the density of the university is suspiciously close to the value needed for eternal expansion) and the horizon problem (widely separated regions of the universe look the same despite there not having been enough time since the Big Bang for them to be in contact). Those problems disappear, Guth wrote in his abstract, “if, in its early history, the universe supercooled to temperatures 28 or more orders of magnitude below the critical temperature for some phase transition. A huge expansion factor would then result from a period of exponential growth, and the entropy of the universe would be multiplied by a huge factor when the latent heat is released.” Guth admitted that his proposal contradicted other observable properties of the universe, but he and others later modified and completed the theory, which became known as cosmic inflation.

Date in History: 27 February 1947