Doug Pensinger wrote:
>
>> Do you understand some other representations of 4D objects in
>> our 3D space?
>
>Such as?
>
>What if you eliminated one dimension as you do in an engineering drawing?
>
That means that you do understand :-)
One of the models for the space part of the Universe [I am not
comfortable with this; I don't know if the Universe can be
*globally* separated into a space-section and a time-section]
is the equivalent to a sphere whose surface has 3 dimensions
[mathematically, it's the solution in R^4 of the vector equation
|v| = R]. So, the Universe - if it is closed! - might be represented
by such sphere that appears, grows, gets to maximum size,
and then shrinks.
If the Universe is open, then the model is slightly more complex,
and I don't know how does time play a part in it. The space
model, at any time, would be a hyperbolic surface, more or less
like the solution of x * y = 1 [or x^2 - y^2 = 1] in R^2.
All this is the *average* picture of the Universe, because there
are local distortions, caused by masses.
Alberto Monteiro
