Did Inflation Solve the Problem of the Universe's Original Gravity?

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The discussion centers on the relationship between the universe's original gravity and the inflationary epoch that allowed the universe to expand. It posits that the gravity of the original singularity could have made it a black hole, necessitating a mechanism like inflation to overcome this gravitational pull. Participants debate whether inflation can be considered a force or merely an event, with some suggesting that it must be stronger than gravity to facilitate the universe's expansion. The conversation also touches on Stephen Hawking's No Boundary Proposal and the implications of gravity's role in the universe's origin. Ultimately, the dialogue highlights ongoing questions about the nature of singularities and inflation in cosmology.
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The gravity of the orginal singularity would make it a black hole.
The original gravity of the universe would give it an escape
velocity; the escape velocity of the Big Bang.
In order to get the universe over its gravity there was an inflationary
epoch that rapidly brought the strength of gravity down everywhere
allowing the universe to really begin.

This is the purpose of inflation: to get the universe over its original
gravity.

Anybody want to argue that the universe didn't begin with gravity?
Then Hawking's No Boundary Proposal is violated and the
there really are "Universal Boundaries" or space then No space.
You can't have it both ways Hawking! :-p

Mitch Raemsch
 
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Macro said:
The gravity of the orginal singularity would make it a black hole.

If the singularity were indeed a black hole,then how could the universe (as weknow it) have begun?
Macro said:
The original gravity of the universe would give it an escape
velocity; the escape velocity of the Big Bang.
In order to get the universe over its gravity there was an inflationary
peoch that rapidly brought the strength of gravity down everywhere
allowing the universe to really begin..

But, it becomes more and more difficult to obtain an escape velocity, as the gravity increase, doesn't it?So, there should have been some other mechanism acting at the time, which must have been much stronger than gravity, isn't it?Then, how can the universe begin only with gravity?
 
All that is necessary is for inflation to be a "stronger force" than gravity! :!)

What else is going to get the universe over its own gravity?
 
Macro said:
All that is necessary is for inflation to be a "stronger force" than gravity!

Inflation is not a force.It is an event.
 
As far as I'm aware gravity became a repulsive force under the tremendous negative pressure and for a tiny moment of time caused the inflation.
 
Macro said:
All that is necessary is for inflation to be a "stronger force" than gravity! :!)
What else is going to get the universe over its own gravity?

:!):!):!) God or natural selection! :-p :-p :-p
 
Better still you can follow Linde and others who prefer to start from the "largeness" of eternal inflation rather than the smallness of a singularity. This reverses things so that instead of an explosion of a hot point you get a bubble of cooling in a hot field.

And perhaps even the idea of inflation as a particular kind of state will eventually be replaced by some more general model of dimensional potential.

But certainly, the questions are still open enough that there is room for no singularity. And even inflation could be replaced by something that "looks a little like it" yet is actually quite different under the skin.

Cheers - John McCrone.
 
Macro said:
The gravity of the orginal singularity would make it a black hole.
The original gravity of the universe would give it an escape
velocity; the escape velocity of the Big Bang.
In order to get the universe over its gravity there was an inflationary
epoch that rapidly brought the strength of gravity down everywhere
allowing the universe to really begin.
This is the purpose of inflation: to get the universe over its original
gravity.
Anybody want to argue that the universe didn't begin with gravity?
Then Hawking's No Boundary Proposal is violated and the
there really are "Universal Boundaries" or space then No space.
You can't have it both ways Hawking! :-p
Mitch Raemsch
The initial singularity was not a black hole. Black holes are static solutions to Einstein's equations and the cosmological solution is dynamic. Thus, the fact that the universe did not collapse at t = 0 might be somehow explained by the value of the Hubble parameter (the speed of expansion) which was infinite at t = 0. On the other hand inflation takes place because there is an accelerated expansion of space, mantaining a constant (finite) Hubble parameter at some time after the big-bang.
 

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