Polls Archive 58 - Finite But Unbounded?

Poll 58 - "Although our universe may effectively appear to be infinite, it is in reality 'finite but unbounded'." Poll ended February 14th 2010.
83.1% agreed, while 16.9% disagreed.

This connects back to Poll 47, which asked "Are We a 3D Sphere on a 4D Hypersphere?". In that entry I said this:

Extra-dimensional spheres are important to all this because they show how our universe could effectively be infinite, but in reality be finite but unbounded. In other words, with each of the dimensions we've been talking about, there are always certain restrictions to that dimension, and you need to move up to the next dimension to move beyond those restrictions.

I returned to this idea in Life is But a Dream, where I said this:

...our Cosmological Horizon is like we're on a boat in the middle of the ocean, except that this boat is not on a 3D sphere like planet earth, it's a finite but unbounded 4D hypersphere - and that's the beginning of a way to imagine how all these hidden connections can start to make sense.

In The Holographic Universe, I talked about this in more detail:

In our four-dimensional universe, it appears that space-time is essentially flat. If it were truly flat, then parallel lines would never meet and our universe would have no boundaries in any direction. NASA's WMAP project has returned results showing that the universe is flat within a 2% margin of error. What does this mean? It means that for most intents and purposes our universe is truly flat. But in the largest picture of all, I believe that the above two ideas are going to be shown to be equivalent - our universe is very close to flat, but there is still a very slight curvature, and the 13.7 billion year "boundary" that cosmology shows us as being our line of time back to the big bang will still show that we are only witnessing a tiny region of a much larger whole, an idea that is central to this project

In An Expanding 4D Sphere, I quoted from the wikipedia article on The Cosmological Horizon, which supports these ideas:

...it has been said that the observable universe is many orders of magnitude smaller than the greater universe that lies beyond the limits of our perception.

Imagine that the entire cosmological horizon is modeled by a sphere that is the diameter of a quarter (24.26 mm in diameter). If Alan Guth's inflationary model of early era cosmology is correct, the universe that lies beyond this “quarter-sized” horizon would conservatively be a sphere as large as the Earth globe itself.

There is still some controversy within the scientific community as to whether or not our universe is absolutely flat, and whether it's truly infinite. It's important to note that for many applications absolute flatness and truly infinite work as approximations, because the curvature we're talking about is so slight compared to the size of our observed universe. Still, I'm very pleased that 83% of the visitors to this blog were willing to accept the proposal that it's actually finite but unbounded, which implies a slight curvature which is creating the 4D hypersphere of our amazing spacetime universe.

Enjoy the journey,

Rob Bryanton

Next: Poll 59 - Placebos and Our Interface with Reality