Michael Stogden nous a écrit :

The only size that you can estimate is the size of the observable universe.
By definition, you can't have access to the size of the whole universe.
You're right. May I suggest you to read this page :
You will see all the difficulties ...

Norbert. (no X for the answer)
knowing the universe - stellar and galaxies evolution
images of the sky http://images.ciel.free.fr