I was taught the universe was infinite.
Stars convert some of their mass to light.
Big Bang theory says that all observers in the universe will see themselves at the center of the expansion. If an observer were at the center of an explosion, the fragments would be fewer in number as he looked outwards. Why do scientist's keep hammering on the Big Bang. It's only a theory, not divine truth. In the expanding universe, space is said to be expanding while at the same time galaxies are not moving.