Bell diagram

This diagram is a timeline of the Universe, representing its evolution 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. For the next several billion years, the expansion of the Universe gradually slowed down as the matter in the Universe interacted through gravity. More recently, the expansion has begun to speed up again as the repulsive effects of dark energy have come to dominate it. The afterglow light seen by the WMAP was emitted about 375 000 years after inflation and has traversed the Universe largely unimpeded since. The conditions of earlier times are imprinted on this light; it also forms a backlight for later developments of the Universe.