Big Bang vs the shape of the universe

[madscience]

In the big bang model, our current universe started with a big explosion from a small object with extremely high density, the debris of this explosion re-grouped and evolved into stars and galaxies. The debris carried initial momentum of the explosion which makes the universe keeping expansion, the proposed dark energy causes the expansion even faster. We do not have any reason to think that such explosion was not uniform in three dimension space. So if the big bang was uniform in 3 dimension space, then, we should be able to find the center of the explosion (or the center of the universe) because the density of the galaxies/stars in the center direction should be higher than the opposite direction, also, the universe should have more or less the spherical shape. However, the various simulated models about the shape of the universe indicate that the universe is like a flat disk shape with thicker in the center.

I am puzzled. Thank you for your help.

Edited March 20, 2010 by madscience

[toastywombel]

In the big bang model, our current universe started with a big explosion from a small object with extremely high density, the debris of this explosion re-grouped and evolved into stars and galaxies. The debris carried initial momentum of the explosion which makes the universe keeping expansion, the proposed dark energy causes the expansion even faster. We do not have any reason to think that such explosion was not uniform in three dimension space. So if the big bang was uniform in 3 dimension space, then, we should be able to find the center of the explosion (or the center of the universe) because the density of the galaxies/stars in the center direction should be higher than the opposite direction, also, the universe should have more or less the spherical shape. However, the various simulated models about the shape of the universe indicate that the universe is like a flat disk shape with thicker in the center.

I am puzzled. Thank you for your help.

 

It is also good to note, we have no reason to believe that the explosion from the big bang was uniform in three dimensional space. Even if it were, the big bang does not just include the expansion and creation of matter, it also is about the expansion of space-time. Space-time expands faster than the matter and energy in our universe spreads apart, that is obvious by astronomical observation. Because of this the Universe is stretched out in a horizontal or vertical fashion (depending on which way you look at it) but essentially it is flat.

 

Imagine a set of small balls on a sheet, if you drop the balls on the sheet while it is all crumpled up, they will be in various arrangements, but if you spread out the sheet, the balls will arrange in a generally flat fashion, with the sheet.

 

 

This is from wikipedia:

"A resolution to this problem is offered by inflationary theory. During the inflationary period, spacetime expanded to such an extent that its curvature would have been smoothed out. Thus, it is theorized that inflation drove the Universe to a very nearly spatially flat state, with almost exactly the critical density."

[Martin]

In the big bang model, our current universe started with a big explosion from a small object with extremely high density, the debris of this explosion re-grouped and evolved into stars and galaxies. The debris carried initial momentum of the explosion which makes the universe keeping expansion,...

 

Please stop right there. It sounds like you are picturing it as an explosion of matter outwards into empty space----as flying debris. That's a common misconception and it's not what the big bang model says.

 

"Big bang" is a bad name for the model which was given to it by someone with a rival theory who wished to discredit the model.

 

Please read the article called Misconceptions about the big bang.

http://www.mso.anu.edu.au/~charley/papers/LineweaverDavisSciAm.pdf

The first page is blank, so scroll down. The very first confusion they deal with is the "explosion" misconception.

Edited March 22, 2010 by Martin