Why is the universe so vast?

"If God created the universe as a special place for humanity, he seems to have wasted an awfully large amount of space where humanity will never make an appearance." Victor Stenger in "God: The Failed Hypothesis: How Science Shows that God Does Not Exist" Every spot of light in this section of the Hubble Ultra Deep Field is a galaxy, and our galaxy has over 100 billion stars.

The universe is observed to be essentially "flat" in the sense that it is almost at the critical density at which it would expand forever. At that critical expansion rate it could form helium, whereas with a much faster rate only hydrogen would form. That rate also makes galaxies and stars possible, so that the heavier elements we are made from could be "cooked" in the nuclear fusion furnaces at the center of stars.

Critical Density and Critical Expansion Rate

From the very beginning the universe had a very precise expansion rate that made possible the formation of galaxies and stars. This preserved the capacity to make the atoms necessary for life.

The universe is observed to be essentially "flat" in the sense that it is almost at the critical density at which it would expand forever. At that critical expansion rate it could form helium, whereas with a much faster rate only hydrogen would form. That rate also makes galaxies and stars possible, so that the heavier elements we are made from could be "cooked" in the nuclear fusion furnaces at the centers of stars. The universe retains the overall hydrogen-helium abundance from this early process.