radius of the universe

The usual analogy to describe the geometry of spacetime
is an expanding balloon. The surface is 2-D, closed, warped
in 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 balloon
model, it should be the same for all observers.

And that would educe a circumference, would it not?



--
Rich

On Dec 23, 5:06 pm, RichD wrote:
The usual analogy to describe the geometry of spacetime
is an expanding balloon. The surface is 2-D, closed, warped
in 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 balloon
model, it should be the same for all observers.

And that would educe a circumference, would it not?

--
Rich

Yep, and the answer is 42 astronomical cubits.

Dave.

On Dec 22, 10:06*pm, RichD wrote:
The usual analogy to describe the geometry of spacetime
is an expanding balloon. *The surface is 2-D, closed, warped
in a 3rd dimension, inaccessible to the balloonists. *However,
the ballon has a center - in the 3rd dimension.

Correction; the internal and external volumes (and the center of
course) are inaccessible, the surface is all that's accessible.

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 balloon
model, it should be the same for all observers.

Sure, why not? The yardstick will be the path of a photon from the
Big Bang to your eye (in the 5-dimensional space in which our
expanding 4D universe is expanding) and that path will resemble an
Archimedean spiral. However it will be slightly altered by such things
as Cosmic Inflation early on, when the expansion rate increased
greatly for a while.

And that would educe a circumference, would it not?

Yeah, but we can never see but a small bit of it.


Mark L. Fergerson

Dear RichD:

"RichD" wrote in message
...
The usual analogy to describe the geometry of spacetime
is an expanding balloon. The surface is 2-D,

Representing space.

closed, warped in a 3rd dimension,

.... Time.

inaccessible to the balloonists. However,
the ballon has a center - in the 3rd dimension.

The "Big Bang".

Now, extend this picture to our expanding 3-D
universe;

the "raisin bread" model..

can we compute the 'radius', the distance to the center,
in the 4th space dimension?

I believe the "distance" has been calculated to be 14.5 Gy (may
have moved again).

Analogous to the balloon model, it should be the
same for all observers.

.... at any given *now*, with the usual synchronization problems.

And that would educe a circumference, would it not?

Not a unique circumference, since there is no guarantee this
Universe is hyperspherical. Might be a dang torus.

David A. Smith

On 23 dec, 14:14, "N:dlzc D:aol T:com \(dlzc\)" wrote:
Dear RichD:

"RichD" wrote in message

...

The usual analogy to describe the geometry of spacetime
is an expanding balloon. *The surface is 2-D,

Representing space.

closed, warped in a 3rd dimension,

... Time.

inaccessible to the balloonists. *However,
the ballon has a center - in the 3rd dimension.

The "Big Bang".

Now, extend this picture to our expanding 3-D
universe;

the "raisin bread" model..

can we compute the 'radius', the distance to the center,
in the 4th space dimension?

I believe the "distance" has been calculated to be 14.5 Gy (may
have moved again).

Analogous to the balloon model, it should be the
same for all observers.

... at any given *now*, with the usual synchronization problems.

And that would educe a circumference, would it not?

Not a unique circumference, since there is no guarantee this
Universe is hyperspherical. *Might be a dang torus.

People have looked for evidence that we can see the same bit of space
from two different directions, and not found any, which doesn't prove
anything much.

My understanding was that the smart money was on the 4-D equivalent of
the saddle-shaped geometry, but I can't remember why.

http://en.wikipedia.org/wiki/Shape_of_the_Universe

--
Bill Sloman, Nijmegen

On Dec 22, 10:06*pm, RichD wrote:
The usual analogy to describe the geometry of spacetime
is an expanding balloon. *The surface is 2-D, closed, warped
in 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 balloon
model, it should be the same for all observers.

And that would educe a circumference, would it not?

It appears that the universe is finite but doesn't have a boundary in
all 4 dimensions. You need to consider the 5th dimension to be able
to say that there is something we could call a center.

I would argue that the universe must be finite for the following
reason: Consider the location and speed of just one electron. This
information must be stored somehow. From quantum mechanics we know
that there is a limit on the resolution. From Einstein we know that
the speed has an upper limit. The only remaining number that could be
infinite is the position in an infinite universe. If this was the
case, the number of bits would be infinite. From Shannon, we know
that it takes energy for each bit that you store. From Einstein, we
know that this energy would have mass. From this, I claim that an
electron in an infinite universe would have infinite mass.

Nice crack pot theory. Huh?

In article ca898971-8be7-43cb-8fd4-4cb1462c5ad0
@v5g2000prm.googlegroups.com, says...
On Dec 23, 5:06 pm, RichD wrote:
The usual analogy to describe the geometry of spacetime
is an expanding balloon. The surface is 2-D, closed, warped
in 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 balloon
model, it should be the same for all observers.

And that would educe a circumference, would it not?

--
Rich

Yep, and the answer is 42 astronomical cubits.

How does that work? 6 x 9 x 1 Astronomical Cubits? 6 x 3 x 3 AC?

On Dec 23, 1:06 am, RichD wrote:
The usual analogy to describe the geometry of spacetime
is an expanding balloon. The surface is 2-D, closed, warped
in 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 balloon
model, it should be the same for all observers.

And that would educe a circumference, would it not?

--
Rich

The radius of the universe is infinite, the diameter is finite.

RichD wrote:

The usual analogy to describe the geometry of spacetime
is an expanding balloon. The surface is 2-D, closed, warped
in 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 balloon
model, it should be the same for all observers.

And that would educe a circumference, would it not?

No. The outside of a black hole's event horizon has a finite diameter
implied pole to pole. The inside diameter is infinite, passing
through the center singularity. Think "tardis" but with a roomier
interior.

Tell us how to locate paired interior poles of an event horizon.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/lajos.htm#a2

RichD wrote:
The usual analogy to describe the geometry of spacetime
is an expanding balloon. The surface is 2-D, closed, warped
in 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 balloon
model, it should be the same for all observers.

And that would educe a circumference, would it not?

Since the 4th dimension is time, by your reasoning the distance to the
centre is 13.7 billion years, give or take.

--
Dirk

http://www.transcendence.me.uk/ - Transcendence UK
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