Science almost certainly knows more about the first five minutes of the universe than it understands about the common cold. But we are hopelessly unsure of what the universe will look like 15 billion years from now. Most of the matter in the universe is contained in a form we have not yet discovered and that may not even consist of atoms or nuclear particles. This mystery matter cannot be seen using any of the normal methods astronomers and physicists use. Since it literally does not radiate forms of light that can be detected by even the most sensitive of current telescopes, scientists give it the name dark matter.
Physicists have lots of experiments running in their laboratories.
Hogan, however, emphasizes that there is little doubt about the most important idea of the big bang model, that the universe expanded from a very hot initial state. Hodge certainly agrees. Some formed all of their stars right away, soon after the big bang. Others appear to still be forming stars, such as the Orion Nebula or M33. Hodge believes much remains to be learned from tracking the evolutionary history of galaxies.