THUMP! What was that? Maybe a nail in the coffin of Dark Energy? Who knows...we shall wait and see if the peer review process is conducted fairly and justly, or if the "powers that be" do all they can to suppress, discredit and destroy this, or any alternative theory that doesn't fit their budgetary guidelines.
What am I talking about? Oh, sorry, I just get exited when more than one idea is finally publicized. :) In a nutshell, and you can read the article for greater detail, a group of scientists has theorized that the reason why it "looks" like everything in the universe is accelerating away in all directions is because we're all riding a huge universal space-time wave, and so objects on that wave will appear to be accelerating away from other objects on that wave.
I don't know if this will hash out to be plausible, factual, whatever, but I am very happy that we finally have some scientists bucking the system and not drinking the dark energy Kool-aid that the scientific community has embraced so passionately that it's almost like a religion. Time will tell if this pans out to be more logical and probable than some elusive and invisible energy culprit.
With that in mind, Gedanken time: Imagine, if you will, that the Universe is a spinning toroid. Not a sphere, or a flat plate, but the largest donut you can possible imagine, where all of us and all the stuff rides on the outer skin in a constant state of curvature going around the toroid. Constant curvature all the way around, ergo everything seems to be accelerating no matter which was you look. Spinning universe, imparting spin on everything else. Hmm. A fixed size, shape and spin requires no limits, boundaries or this concept of infinite expansion, because that's not happening.
Additional: Don't care how the toroid was made. Don't care what's beyond it, or what's inside it. Embrace infinity in both directions, infinitely small and infinitely big, including infinite existence. Always has been, always will be, enjoy the ride and stop worrying so much about that which you cannot reason within the infinitesimally small existence you inhabit along the infinite space-time time line.