:salam2:
Allah (SWT) has given us some information which guide us to have some idea about Allah Subhanahu Wa Taala.
There are several hadiths which tell us that the seven heavens and the earth is surrounded by the Kursi (footstool) and this Kursi in comparison to Allah's Arsh (Throne)is like a ring in a desert.
Then Allah (SWT) also says that the vastness or the length and breath of Jannah will be like the heavans and the earth, meaning that the Paradise will be spread in all over the region we call Universe, plus the other six Universes which we cannot even see. Just this visible universe alone is so big that with the help of most powerful telescopes we can see galexies which are around 10 billion light years away. This universe is considered to be 15 billion years old so let us say its diameter is 15 billion light years. If we consider the other six universes also 15 billion light years wide. That gives us a total of 105 billion light year for the region which will be the Paradise.
The last person coming out of Hell will get a Jannah equal to 10 earths. So the people who will live in the upper levels of Paradise will get many light years of region to themselves.
In a Hadiths Prophet Mohammad has said that the upper levels of Paradise will look like we see planets from earth. Subhan Allah, at that time when planets and stars were considered small little bright objects stuck in the sky, our Prophet gave such a perspective that only in this century we can really appreciate and understand.
So what I am saying is that the people of Paradise will be spread all over the universe, some will be billions of light years away from one another, but according to the Hadith they all will see Allah (SWT) at the same time.
The nearest galexy Andromeda which is only 2 million light years away from us and is 200 thousand light years wide appears as a faint blob, and smaller than moon in size. Any other galexies, we can't even see with naked eyes.
What I am trying to say here is that since all the people of paradise, who will be spread all over the universe will see Allah (SWT) at the same time, it suggest 2 things:
1. Allah (SWT) must be big enough for all of us to see him at the same time.
2. Light must be travelling much faster than it travels in this current universe.
There is a Hadith (which I have heard but I don't have its reference) says something like this:
Allah (SWT) says that He cannot fit in the regions of Heavens and the Earth but He can fit in a believer's heart.
(If anyone have read this hadith then please post here its details.)
Maybe Allah is talking here about his size, but who knows. Only Allah knows the best.