May 1, 2014
A British man named Samuel Shenton, then in his early twenties, was doing research in the British Library at Bloomsbury when he came upon a book called Zetetic Astronomy: Earth Not a Globe. Published in 1881 by a man named Samuel Rowbotham, the gist of the 430-page book is summed up neatly by its subtitle: The Earth, Rowbotham proposed, is flat.
The inflationary model of the universe, developed in the 1980's by Alan Guth (MIT), Andre Linde (Stanford), Andreas Albrecht (UC Davis) and Steinhardt, was designed to resolve these very same problems, relying on a period of exponential hyper-expansion, or inflation.
Conceptually, the ekpyrotic model is very different. There is no inflation or rapid change happening at all. The approach to collision takes places very slowly over an exceedingly long period of time. It is quite fascinating that rapid change and very slow change can produce nearly the same effects. The difference results in one distinctive observational prediction, though: Inflationary cosmology predicts a spectrum of gravitational waves that may be detectable in the cosmic microwave background. The ekpyrotic model predicts no gravitational wave effects should be observable in the cosmic microwave background.
In the ekpyrotic model, when the two three-dimensional worlds collide and "stick," the kinetic energy in the collision is converted to the quarks, electrons, photons, etc. that are confined to move along three dimensions. The resulting temperature is finite, so the hot Big Bang phase begins without a singularity. The universe is homogeneous because the collision and initiation of the Big Bang phase occurs nearly simultaneously everywhere.
The energetically preferred geometry for the two worlds is flat, so their collision produces a flat Big Bang universe.
Posted by Orrin Judd at May 1, 2014 6:54 PM