In the beginning, there was a bang. A very big bang. Nothing exploded into something. Quarks and leptons collided violently in an intense fireball of plasma. As the plasma expanded and cooled, the collisions became less violent, and particles joined together to form protons and neutrons and electrons, then nuclei and atoms and molecules. Huge clouds of these particles coalesced into galaxies of stars and planets, still expanding, always expanding, away from the central point... More >>>