I have always wondered how we know for sure how big the Universe is. I actually wonder if we are able to see all the light that is produced in the Universe. For portions of the Universe that have traveled away from us on the farthest edge as we travel (expand) in the opposite direction away from the opposite edge, is there a limit or space and time in which light will never reach us?
Your question is relevant and spot on in your reasoning. The fact is we don’t know how large or how old the universe is but, we have some ideas. The size is based on measurements and observations and taking red shift into account.
Because of the big bang theory there are certain assumptions that are made about the speed of the expansion of the universe. Because we can only see out to about 13-1/2 billion light years we suppose that is the size. The relatively recent very long exposures of the Hubble Space telescope of areas that were thought to be blank have been an eyeopening experience for Astronomers. Literally tens of thousands of galaxies that were not known to exist were seen and they were farther away than could have been explained a decade or so ago.
If a longer exposure didn’t show any more galaxies than we have already seen it would not prove there are none, it would be possible as you stated in your comment that light has simply not had enough time to reach us because it is so far away.
It is entirely possible that the universe is substantially larger but not substantially younger. It makes sense that the further away objects are from the center of the universe the faster they must be traveling. Since the number of photons decrease at the square of the distance and since leaving the shutter open for 14 days only illuminated to 13-1/2 Billion years I would wonder what we would see from a 200 day open shutter. If we see twice as many galaxies they would have to be further away, again expanding the known size of our universe.
I never took any stock in the String Theory stuff anyway.
I believe in God. I believe that God created the Heavens and The Earth. I don’t suppose to know how but believe He did. I believe He has created worlds without end, so to me the size of the universe is infinite.
I also don’t quite think I am ready to totally accept black holes either. I’m not saying they don’t exist but I’m certainly not ready to say they do, I don’t think the book is closed on that research yet. It seems like infinity goes both ways, maybe we can always divide matter into smaller parts and get smaller and smaller.
Being alive in a time when the observations that we have seen in the last several decades has been fun.