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Topic: closed universe, flat space?
Replies: 48   Last Post: May 5, 2013 2:45 PM

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 dan.ms.chaos@gmail.com Posts: 409 Registered: 3/1/08
Re: closed universe, flat space?
Posted: May 4, 2013 2:46 AM

On May 4, 2:48 am, RichD <r_delaney2...@yahoo.com> wrote:
> On Apr 29, Dan <dan.ms.ch...@gmail.com> wrote:

> Into what?  A toroid?
You can't actually fold a blanket into a toroid .
This is the 'intrinsic curvature' of the toroid .
http://www.rdrop.com/~half/math/torus/torus.curvature.map.png

>So you're saying, that an inhabitant of a toroid or
>cylinder - on its 2-D surface - cannot draw any shape
>which will tell them it's warped? I find that hard to swallow.

I can see it's warped - if I'm not in the cylinder surface .
But the guy in the cylinder surface only interacts with stuff from
WITHIN the cylinder surface .

That means that when you fold a paper into a cylinder , light travels
along the folded path . Perception gets curved along with the objects
of perception , resulting in apparent flatness. And that's good enough
for physicists , since they can't get out of the universe , or the
cylinder .

An easy way to understand this is :
Imagine you were turned upside-down (ignoring gravitational
effects) . How could you tell that you got turned upside down? By
looking at the rest of the world, that is still right-side up. But, if
you look at your hand , it still looks unchanged from when you were
normal-oriented . You can't tell if you're upside down by looking at