Ovidio Universe: Birth of inflationary universe

 According to the inflationary scenario, in the first trillionth of a trillionth of a second a mysterious antigravity force pushed the universe to expand much faster than originally thought. The inflationary period was incredibly explosive: the universe expanded at a speed far superior to that of light. (This does not constitute a violation of Einstein’s claim that nothing can travel faster than light, since it is empty space that is expanding.)In a fraction of a second, the universe expanded by an unimaginable factor, equal to 1050. To visualize the power of the inflationary phase, imagine rapidly inflating a balloon on which galaxies are painted on the surface. The universe we see, populated by stars and galaxies, is not located inside the balloon, but on its surface. Now draw a very small circle on the balloon. The latter represents the visible universe, that is, everything we can see with our telescopes. (For comparison, if the entire visible universe were as small as a subatomic particle, then the real universe would be much larger than the universe we see around us.) In other words, the inflationary expansion has been so intense to put whole regions of the universe, located beyond our visible universe, beyond our reach. In fact, the inflation was so huge that in our vicinity the balloon appears flat, a fact that the WMAP satellite has verified experimentally. Just as the Earth appears flat to us because our dimensions are small compared to its radius, the universe appears flat only because its curvature manifests itself on a much larger scale.