h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Is it feasible to say that another reason for the accelerating expansion of the universe is that the universe is rolled up several times in a higher dimension and is slowly unravelling?

For example, if you take a large sheet of paper to represent the 3D universe, and then roll it up several times, it automatically begins to unroll itself. If you think about it unrolling faster and faster as it goes on, is this a plausible picture of what the universe is doing?

Eventually, of course, the universe would 'flatten' out and we would be left with no gravity at all.

Another suggestion is that the speed of light is slowing down over time. I don't remember exactly how that "solves" the problem, but I'm pretty sure it's inversely related to the value of the cosmological constant.

This is probably utter nonsense... but it sounds pretty good to me. Because I'm a dope, someone explain to me why it is that a rug starts to unroll faster and faster. Is it the decreasing mass of the still-rolled-up part of the rug? That seems like it would make sense with the universe too -- as matter spreads out, there is less and less gravitational attraction. So if there is some force causing the universe to expand at all, it would make sense that its expansion is accelerating.

Hey y'know like Earth speeds up at certain points in it's orbit - what if (big IF) the universe is interacting with another object, and that is causing it to accelerate. Perhaps the universe is "orbiting" something maybe it's interacting with a bigger universe lol

That's pretty much right. An unrolling rug unrolls faster as it goes because of conservation of angular momentum, which is the moment of inertia of the rug (which depends on how the mass of the rolled up part of the rug and its size) multiplied by its angular velocity. As the rug unrolls both its mass and size decrease, so the moment of inertia goes down; so the angular velocity has to increase to keep the momentum constant, so as it unrolls the rolled up bit turns faster and unrolls quicker.

As for the expanding universe, the gravitational attraction between all the mass will go down as the universe expands, but since any force that is causing the universe to expand faster must also go down (or it will violate the law of conservation of energy), the amount the expansion is accelerating by will depend on which of the two forces decreases quicker.

Of course this all depends on whether there is any 'extra' force in the universe pushing everything apart, or if we really don't know bugger all about gravity after all.

But how did the universe get rolled up in the first place? When rolling op a rug or a piece of paper, you add energy to it. This energy causes the unrolling. What energy was used to roll up the universe?