Answer: Hope this helps you!
We still don't know how much the universe extends/how big it is.
Even after many world changing discoveries about the universe, it is still unclear if the universe extends forever or not. There is no proof whether the universe ever ends, or if it is infinite. Ever since the time of the ancient Greeks, and even in the current days it is still unknown. Aristotle, a Greek astronomer developed the basic principles of the universe, and he was pretty much almost right. Even though he did this, it was only 384-322 BC, and back then along with developing the basic idea of the universe, he also inferred that the universe was infinite. Moving on to other astronomers like Aristarchus, Giovanni Cassini, Jean Richer, Heinrich Wilhelm Olbers, they all discovered something new in the field of astronomy, however, none of them, even if they inferred if space was infinite or not, nobody ever found out whether the universe had an end. Nobody was ever able to solidly support their claims whether the universe was never ending or not.