''Are you certain that's not just a measured estimate of the minimal size the universe must be? As far as I've heard, noone to date has been able to place an upper bound on the size of the universe. None of the tested theories we have to date say anything about such a limit.''
On the dot mate. Yes, that is exactly what it is, and since we know the universe is around 15,000 million years old, it is, i would say, a mainstream.
Source? All the age of the universe tells us is how far out the furthest visible stars should be, depending on which cosmological model you choose. Even though the Big Bang model says that all points in the universe were once spaced infinitesimally close together, that doesn't mean that today all points in the universe can only be ~15 billion light years apart. You'll learn this when you study the maths of General Relativity.
I know this is wrong. It was a pure mad speculation on my part, for instance, and a very quick one at that, is that spacetime drags matter. I was concluding the error of my understandment of your previous statement.
Don't you think this kind of hurried speculation is what gets so many of your posts tossed in the Pseudoscience forum? Don't get mad at the moderators, you're responsible for making sure your ideas and concepts are sound and thoroughly considered before you post them in the Physics section.
AAAhhhh... i thought you meant general physics i have learned in my college studies. Well, i don't have any of the kind you require yet, i am developing them though.
Good, and I encourage you to keep at it. But you can't jump the gun and try to start a serious discussion about something in the Physics section until you have developed this knowledge. You can ask all the questions you want and seek advice about topics you're learning, but it's pointless to toss ideas out there if you're not even personally sure that they're applicable. I think that as you try and understand the maths and concepts of modern physics in full detail, you'll find yourself constantly pushing the ball further back until you're studying springs all over again (at a more advanced level). A standard education in physics starts with the basics of classical mechanics, then gives a sniff of some modern physics, then goes back to classical physics, then again to modern physics, and then back to classical mechanics yet again. There's a lot of stuff to cover that's glossed over in the early stages, but that doesn't mean it's not crucial for your overall understanding. No pain, no gain.