radius of the universe

RichD · 2008-12-23T06:06:28+00:00

The usual analogy to describe the geometry of spacetimeis an expanding balloon. The surface is 2-D, closed, warpedin a 3rd dimension, inaccessible to the balloonists. However,the ballon has a center - in the 3rd dimension.Now, extend this picture to our expanding 3-D universe;can we compute the 'radius', the distance to the center,in the 4th space dimension? Analogous to the balloonmodel, it should be the same for all observers.And that would educe a circumference, would it not?--Rich

Dec 23, 2008 45 Replies

Rate this thread:

N:dlzc D:aol T:com (dlzc) 17 years ago

Dear RichD:

You clearly have difficulty separating the specifics of the analogy from the concepts underlying its intent.

Is there a linear combination of the 2D surface axes (representing 3D space) that can generate the "radius"? No.

Is there a 1:1 correspondence between the balloon radius at any instant and the size of the "balloon Universe" at any given instant? Yes.

See, you do understand. And if you don't agree with this, you can start with the raisin bread analogy...

David A. Smith

Vote

Sam Wormley 17 years ago

A 4th uncurled-up spacial dimension would render orbits unstable.

Vote

Richard Henry 17 years ago

10-D

Vote

JosephKK 17 years ago

Earth's orbit is not stable, nor is Mercury's, nor any other planet in this solar system, nor any moons. That almost argues for a non-rolled-up added dimension or more.

Vote