Visualizing the "Flatness Problem" ??

[Widdekind]

Back at the Big Bang, the expansion of the universe was infinitely rapid, [math]H(t=0) \rightarrow \infty[/math]. This is visualizable, as the vertical, 'infinitely steep', asymptote, of the Cosmic Scale Factor, plotted as a function of time, simply in 1D:

 

or, as a more attention-grabbing 'surface-of-revolution':

 

Thus, at the "bottom of space-time", back at the Big Bang, the fabric of space-time becomes asymptotically flat, with a flat, planar, tangent surface. Is that a way of "visually explaining" the cosmological 'Flatness Problem' ??

[pantheory]

Back at the Big Bang, the expansion of the universe was infinitely rapid, [math]H(t=0) \rightarrow \infty[/math]. This is visualizable, as the vertical, 'infinitely steep', asymptote, of the Cosmic Scale Factor, plotted as a function of time, simply in 1D:

 

Thus, at the "bottom of space-time", back at the Big Bang, the fabric of space-time becomes asymptotically flat, with a flat, planar, tangent surface. Is that a way of "visually explaining" the cosmological 'Flatness Problem' ?? or, as a more attention-grabbing 'surface-of-revolution':

No, the Big Bang model does not propose an infinitely rapid expansion of the universe during the Inflation era (the Inflation hypothesis), it only proposes a very rapid Inflation process, in most interpretations. Inflation accordingly was faster than the speed of light.

 

Instead the flatness problem of the Big Bang model relates to the underpinnings of the Big Bang model itself, which are Einstein's cosmological equations based upon his Theory of General Relativity (GR). GR uses Riemann geometry which relates to the proposal that space in non-Euclidean. Euclidean geometry can also be called a "flat geometry" in that everything would simply have simple length, width, and depth co-ordinates and there accordingly would be no curvature of space if the universe were that simple. But when looking at the universe as a whole, all indications indicate that the universe is flat and simple, and that space is not curved as proposed by Einstein and his theory of gravity. By proposing the Inflation hypothesis theorists believe that if the universe expanded very quickly (faster than light) that it could appear to us that the universe is Euclidean/ Flat even if at a much larger scale it accordingly could be curved in some way. So the flatness problem is the contradiction of observations which seem to suggest that space is Flat, and that Einstein and the Big Bang model are wrong. Inflation supposedly proposes a theoretical way to get around what is being observed.

 

Most consider the flatness problem to be a fine-tuning problem of the Big Bang model, that requires the density of matter/ energy in the beginning universe, to have according been very close to an exact number during most of its volume expansion phase, otherwise the observable universe would now appear to be much different.

 

 

Edited July 22, 2011 by pantheory

[36grit]

It's like pokeing a stick in water.