What would be more realistic for a universe where FTL is possible?

Question

I am working on my own project with applying science to Star Wars. I try to meld the fantasy with as much real science as possible, but I am having a problem with the size of the universe. I am writing this from a perspective of a scientist living in the Star Wars galaxy. I have to assume that scientist in a GFFA know (at least a little better than us) if the universe is infinite or finite in size. In the real world, scientists conclude that the universe is flat with a 0.4% margin of error. I am therefore going with a flat universe, and I read that the universe being flat does not automatically make the universe infinite. FTL travel is incredibly commonplace and easy in Star Wars, but someone on TOR.com determined that it would take 11 years to reach another galaxy 100 million light years away SO FTL does still take time and it doesn't mean they would've explored all the universe by now. In canon, intergalactic travel is very dangerous, so it makes sense why they haven't left the galaxy.

Based on all this; I ask. Should I go with an infinite or finite size of the universe in my project? I am leaning towards finite because an infinite universe messes with my head and the existence of the Force doesn't make infinity a popular option but give me your totally honest opinion.

Answer 1

What experiment could your scientist do to determine if the universe is finite or infinite in space? From our slower-than-light perspective, we can look in any direction and see the edge of our light cone -- the universe is definitely timewise finite in the past direction, so we can only see ~46 billion light years or so. We know the universe is at least that big, but no experiment we can perform tells us how much bigger.

What changes with faster than light travel being possible? Well, you can see outside your light cone. Just zip a few lightyears over (FTL) and take a look -- you'll now see a few light years beyond the previously visible "edge of the universe" in that direction.

But by your numbers, FTL travel in your universe is limited to very very roughly 100 kilolightyears/year. So suppose that the scientist's thesis advisor was very, very dedicated to this question. And suppose he's a long-lived species -- I believe 900 years is traditional in your universe. He got his PhD, spent 400 years flying west, took a photo, spent 400 years flying back home... and had one human lifetime to glory in having confirmed that the universe is at least 40 million light years bigger than those ignorant pre-FTL folk knew.

That's a difference of one part in a thousand from what we know now. It's certainly not a proof of infinity, nor likely to be a disproof of it. So in practice this life was wasted -- nothing was learned.

In summary -- it just doesn't matter. Our ignorance on this matter very likely applies to the characters in your world as well. They can fly their entire life in any direction and still be within spitting distance of where they started, relative to what they can see. Any story, even one spanning generations, will take place in the tiniest bubble of a galaxy group, a few million light years across. Infinite vs finite is a distinction without a difference.