Relativity Lite

Cosmology | 85 Figure 7. “A representation of the evolution of the universe over 13.77 billion years. The far left depicts the earliest moment we can now probe, when a period of ‘inflation’ produced a burst of exponential growth in the universe. (Size is depicted by the vertical extent of the grid in this graphic.) For the next several billion years, the expansion of the universe gradually slowed down as the matter in the universe pulled on itself via gravity. More recently, the expansion has begun to speed up again as the repulsive effects of dark energy have come to dominate the expansion of the universe. The afterglow light seen by WMAP was emitted about 375,000 years after inflation and has traversed the universe largely unimpeded since then. The conditions of earlier times are imprinted on this light; it also forms a backlight for later developments of the universe.” * Given the enormous rate of expansion in the inflationary period, if the universe has a spherical shape, the current radius of the universe should be so large that it would appear flat to us, as ants walking on the surface of the US Capitol dome would perceive it to be. Inflationary expansion would also drive an originally saddle-shaped universe to be flat. If it were originally flat, it would remain so. If we look at the map of the radiation left over from the Big Bang, the “afterglow light pattern” at 370,000 years, labeled as such in time in figure 7 and fully shown in figure 8, we see that this Cosmic Microwave Background (CMB) radiation, as it is more convention- ally called, has fluctuations in temperature in the fifth decimal place and fluctuations in brightness: “If the universe were flat, the brightest microwave background fluctuations (or * NASA/WMAP Science Team, “Timeline of the Universe,” National Aeronautics and Space Administration, last modi- fied December 21, 2012, https://​map​.gsfc​.nasa​.gov/​media/​060915/​index​.html.