Search All of the Math Forum:
Views expressed in these public forums are not endorsed by
NCTM or The Math Forum.



Re: closed universe, flat space?
Posted:
Apr 25, 2013 2:50 PM


> There is still no mathematical proof showing that null Ricci tensor > with nonvanishing 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 selfstyled 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 3dimensional 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 3sphere . 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 . http://upload.wikimedia.org/math/5/d/3/5d3493e432ad0bdab4e10a3896368856.png
> ?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 'selfstyled 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 .



