Much of this question can be answered via Big Bang Cosmology. Given the evidence we currently have, the universe began 13.7 billion years ago. Because of this, we can think of the universe having a "temporal" edge that is at least 13.7 billion years across. In terms of space, however, there is no evidence of any sort of physical boundary (in the typical sense) , so we can say that there is infinite space in the universe (which isn't currently visible.
Okay, I know the whole 'it is not infinitely large' argument already. The argument has one major flaw. This flaw is that the universe is constantly expanding. In order for an infinite number to be infinite, it must go on forever, correct? In order for it to go on forever it must always expand. This means that the universe is infinitely large, as it is always expanding.
Its logical when you think about it. How could their be an end to the Universe. Although Scientists say that it is constantly growing, their is still no defined boundary that shows where the universe finishes - therefore, in space, which all the experts agree is infinite, the universe continues for as far as space does, a infinite space.
It isn't because infinite is constantly getting larger, if you can comprehend that the universe is like a bubble that is getting blown forever. Time and space are the same thing so the further you go the younger the universe gets. So the edge of time and space is nothing but intense heat and plasma which was the byproduct of the big bang. So as long as the universe is expanding at FASTER than the speed of light so it is "INFINTELY" expanding as long as the universe exists. So yes it is infinite as long as time doesn't come to a end.
Universe is infinitely large. It is technically as well as Logically correct. It is well proved by our scientists with various investigations and researches. Even in various religious aspects it is a belief. The expanding Universe theory says that the Universe could expand forever [that corresponds to a 'flat' Universe]. And that is probably the model of the Universe that we feel closest to now.
Since God by difinition is of the infinite, only He can fully understand this. Becaus we are human beings our knowldge is limited. We are constantly searching for the truth. With the passing of time, we will devolop tools to better understand wha tis happening in our universe. In the mean time we our learning. Who know what we will know 100 years from now? Who knows today where we may be able to travel to to a century from now.
This really got me thinking. Well, Big Bang cosmology cannot really decide it, since the Big Bang could have equally happened for a fully flat and thus infinite universe. Current measurements imply a flat universe, which could be huge and spherical ... Or not.
So how can we tell? Actually I think we can prove the universe is infinitely large because of black holes (no seriously, stay with me on that). If General Relativity is true (and that is what current physics assumes), spacetime inside a black hole is drastically curved. Even if no singularity has formed, a collapsing star will result in a small black hole in its center, in which spacetime exactly behaves as if there would be a singularity.
Doing a bit of math [to calculate the volume of a black hole around the singularity in General Relativity as an integral over the metric tensor], I should get something like infinity. So if there's only one single black hole in the universe, the spatial volume of the universe has to be infinite according to contemporary physics. And there surely is.
The universe is not infinite. It's not even a googolplex long. But you would never reach the end because it would you lead you to where you started. A good way to explain is that we are in a giant sphere. Even if you go straight you'll end up in the place you started.
WMAP allows us to measure basic parameters of the geometry of space. Part of that is the overall shape (flat to a decent degree of accuracy) - so while it may be infinite in terms of expansion, the time to do so has not been i.E. It's not infinite in any meaningful sense of the term given we have a decent time frame of the origin itself (Big Bang).
The universe is unbelievably vast, and at the rate it is expanding it isnt possible to measure the size of the universe. However the universe still has a size, at the moment of the big bang, the universe was small compared to now, and there are many predictions of size and rate of expansion then, however to have an infinite size, the universe would have to expand at an infinite rate. We know the universe has never expanded at anywhere close to an infinite speed so by definition of of infinite, the universe cant be infinite