The word "infinite" refers to something that seems to have no boundaries, like the sky. We cannot see the beginning or ending of the sky around us; it seems to have no limits. It seems to go on forever. When astronauts leave the boundaries of Earth's atmosphere in the space shuttle, what they see is infinite space; space that has no limits or boundaries, but seems to go on forever. We know that we live in a galaxy that is heavily populated with stars, planets and moons.
In fact, if you had a powerful telescope, you could see a galaxy that is closest to us; the Andromeda galaxy. Galaxies are not infinite; they have boundaries that may be spiral or globular in nature. However, the space between galaxies is infinite; it has no boundaries that we are able to see. Thus, the entire universe as we know it is infinite; we cannot see its beginning or its end. We can see no boundaries of the universe. That's difficult concept to grasp because we are used to things having limits and boundaries. The size of the universe is infinite,and we are not able to grasp this concept.
In fact, if you had a powerful telescope, you could see a galaxy that is closest to us; the Andromeda galaxy. Galaxies are not infinite; they have boundaries that may be spiral or globular in nature. However, the space between galaxies is infinite; it has no boundaries that we are able to see. Thus, the entire universe as we know it is infinite; we cannot see its beginning or its end. We can see no boundaries of the universe. That's difficult concept to grasp because we are used to things having limits and boundaries. The size of the universe is infinite,and we are not able to grasp this concept.