Our kind of life depends on complex arrangements of atoms. Atoms cannot stick together at temperatures of millions, or even thousands, of degrees. But when the first atoms formed, they were still hot, and they spread nearly uniformly throughout the universe. If the temperature, pressure, and density were always perfectly uniform, there would never have been a habitable place in the universe. Life’s habitat must have moderate temperatures, those that make water liquid, neither frozen as ice nor boiled into steam. But a much hotter source must supply life with light as well as heat. A perfectly uniform universe cannot have both a star like the Sun and a planet with moderate temperatures like the Earth.
Happily for us, the universe was not perfectly uniform. There were fluctuations of temperature, pressure, and density. These fluctuations had to exist if the fiery mixture was to separate into concentrated regions, some hot enough to supply light and others at moderate temperatures where atoms could form the complex arrangements that life requires. The light had to separate from the darkness.
Happily for us, the universe was not perfectly uniform. There were fluctuations of temperature, pressure, and density. These fluctuations had to exist if the fiery mixture was to separate into concentrated regions, some hot enough to supply light and others at moderate temperatures where atoms could form the complex arrangements that life requires. The light had to separate from the darkness.
