Creation Theory
the Big Bang

In the beginning, all mass was located in one spot at infinite temperature and infinite density--this was called a singularity. The universe began 10 to 20 billion years ago as the result of an explosion called the big bang. Immediately after the explosion,' the universe consisted chiefly of strong radiation. This radiation formed a rapidly expanding region called the primordial fireball.

After a few hundred years, the main part of the fireball was matter, chiefly in the form of hydrogen. It also included a small amount of helium and other light elements. Today, faint radio waves are all that remain of the radiation from the original fireball. Like the radiation, the matter continued to decrease in density after the explosion. In time, the matter broke apart in huge clumps. The clumps became galaxies. Smaller clumps within the galaxies formed stars. Part of at least one clump became a group of planets--the solar system.

The galaxies are still moving away from one another, and the best current evidence indicates that they will move apart forever. But astronomers do not rule out the possibility that all the galaxies will come together again in about 70 billion years. If this happens, all the material in the universe will explode again, resulting in a new phase of the universe resembling the present one.

excerpted from The World Book Encyclopedia