Inflation and Curvature: Examining the Relationship Since the Big Bang

[Pianorak]

Since the very rapid expansion of the Universe, ie Inflation, caused curvature to be smoothed out, the assumption must be that curvature existed between the time of the Big Bang and the start of Inflation. If that is correct, is this borne out by the Planck or any other theory?

 

[QuantumQuest]

I think that this question effectively boils down to the interaction between Higgs field and gravity. It is the last unknown number in the standard model and is on active research.

 

[Ken G]

It is unknown if there was curvature, but what inflation does is allow there to have been curvature, yet make it undetectable, hence making it consistent with observations. It is intended to deal with the "flatness problem", which is a form of "fine tuning problem"-- problems where the universe seems like it ought to have an arbitrary value of something, but instead it has a very specific and non-generic value of that parameter. It's not at all clear that fine tuning problems are real problems in science, but inflation does not only solve that one "problem", it helps with many others too, and some hold that it even makes predictions we had no reason to expect to be true that are borne out by the CMB. Perhaps the best way to frame that is that inflation unifies the solutions to these various "problems" under a single heading.

 

[Pianorak]

Quantum Quest and Ken G - Very many thanks for your comments. Food for thought.