cle (no charge) is also neutral. The early universe had nearly equal amounts of matter and antimatter, with a light excess of matter—about one extra particle for every 100 million pairs of anti-matter. Because matter and antimatter blow up one another in a burst of electromagnetic radiation (energy in the form of particles called photons, visible light is a kind of electromagnetic radiation) the universe we see today is dominated by the extra matter that couldn’t find antimatter with which to blow each other up. Apparently leaving us with all the leftovers from a ton of explosions that shaped the universe.The Big BangThe explosive beginning of our universe, the Big Bang marks the earliest time we can find with current physical theory. Theory is supposed to guide our understanding of the first fraction of a second, since we can’t recreate the extremely high temperatures that existed during the earliest history of the universe in any laboratory. What this theory tells us is that from the initial state in which matter and radiation are both in an extremely hot and dense form, the universe expands and the matter cools. At that time, it is believed that all the forces of nature—gravity, electromagnetism, and the strong and weak nuclear forces—were unified.The evolution of the earliest universe is not understood very well because it is not clear exactly what laws were at work. However, it is known that by the end of the first second of time, the building blocks of matter had formed. By the end of the first three minutes, helium and other light nuclei had formed but for a long time, temperatures remained too high for the formation of most atoms. At around one million years following the Big Bang, nuclei and electrons were at low enough temperatures to bond to form atoms. But the universe didn’t start to look like it does today until small differences in the matter distribution were able to condense to form...
