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Author Topic: Why is the Big Bang model favoured?  (Read 7943 times)

Offline graham.d

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Why is the Big Bang model favoured?
« Reply #25 on: 09/02/2010 17:08:49 »
As I have said before, it is very hard to explain some of the less intuitive results of GR without some knowledge of differential geometry.

To address your point and ball analogy, farsight, it is not that the universe is expanding that is suggestive of dark energy (or any sort of pressure), but the acceleration of the expansion.
 

Offline Soul Surfer

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Why is the Big Bang model favoured?
« Reply #26 on: 10/02/2010 23:10:01 »
Many people who wish to propose alternatives to expansion to explain the red shift forget some of the more subtle aspects of observations of this in the form or indirect observations of the many other gas clouds that light has passed through at different distances.  This caused what is known as the "Lyman alpha forest" on the Lyman alpha emissions from very remote active galaxies.
 

Offline yor_on

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Why is the Big Bang model favoured?
« Reply #27 on: 28/02/2010 21:12:46 »
It's a positive pressure, graham, despite what the equations say. A negative pressure would make the universe contract, not expand. Gravity is a pressure gradient, and if the pressure is uniform there is no gravity, but the universe still expands like a ball of compressed gas. Let's face it, the early universe was very dense, but it didn't collapse. Look up stress-energy along with stress and pressure, and think stress ball. Squeeze it down in your fist, and let it go. It expands. 



Farsight, look here for an explanation of how it seems to be thought to work.
Negative energy
 

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Why is the Big Bang model favoured?
« Reply #27 on: 28/02/2010 21:12:46 »

 

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