Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

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

 Messages: [ Previous | Next ]
 dan.ms.chaos@gmail.com Posts: 409 Registered: 3/1/08
Re: closed universe, flat space?
Posted: Apr 25, 2013 2:50 PM

> There is still no mathematical proof showing that null Ricci tensor
> with non-vanishing Riemann tensor.  Even if you are right, Riemann
> tensor does not play a role in the final interpretation of
> differential geometry.  The Riemann tensor represents only one of the
> steps from the Christoffel symbols to the field equations.  <shrug>

http://sgovindarajan.wikidot.com/ricciflatmetrics

> Koobee Wublee is also very amazed that the solutions to the FLRW
> metric would be interpreted as expansion of space while the
> Schwarzschild metric would be interpreted as the geometry that
> determines how an object is going to behave --- same mechanism in
> mathematics but interpreted in two drastically different ways.  If
> there is not enough or no negative mass density in vacuum, Koobee
> Wublee supposes space would collapse back onto itself dragging all
> objects in space along with it, no?  So much for the scientific axiom
> that the laws of physics are the same everywhere and whenever.
> <shrug>

I have no idea what you're talking about . And I'm pretty sure you
have no idea what you're talking about .
"Spacetime tells matter how to move; matter tells spacetime how to
curve" -John Archibald Wheeler

>So, the flatness of cosmology is determined through how much of
>negative mass density is in vacuum. If there is more negative mass in
>vacuum, the universe will expand its acceleration just like
>antigravity of the Newtonian system. Koobee Wublee find that very
>amazing that the self-styled physicists would choose to embrace
>negative mass density in vacuum while vehemently denying the Aether.
><shrug>

Ether isn't needed in General relativity . It's a deterministic theory
where you have no arrow of time apart from the expansion of the
universe. Like a 3d holographic movie. It doesn't matter how you play
it or view it . An object moving at constant velocity can consider
itself at rest . Whether or not any notion of 'absolute space' of
'absolute time' will be needed in a unified theory is beyond the scope
of this discussion .

> No, Koobee Wublee cannot generalize an ordinary 3-dimensional object
> with the profoundness of curved space where space is able to curve
> back onto itself.  Please present the metric.  <shrug>

Here's the metric for a 3-sphere . Add an additional time dimension
(an extra row and column in the metric tensor with -1 in the corner
and zero in the other entries ) and you're ready to calculate
trajectories .

> ?All science came out of a sea of irrational speculations plus a tiny
> trace of rational one, but scientific methods when properly applied
> allow science to find just that rational one.  <shrug>?
> --- Koobee Wublee, 2013

What methods count as 'scientific'?
Also ,you had to find the most reliable source to quote , right? And
you call me a 'self-styled physicists' . You're not deserving of the
title, however , you do qualify for hypocrite .

> It is amazing that you certainly have spent a lot of energy engaging
> with the point you have claimed not to see.  <shrug>

It's always worthwhile to see if meaningful dialogue and understanding
can be achieved . Since, in the present case , it is impossible, rest
assured that I won't repeat the same mistake , and not waste any more
energy .