Rumraket wrote:newolder wrote:Rumraket wrote:newolder wrote:With regard to inflationary theory and fine tuning, Andre Linde is quoted in a
SymmetryMag post on The Growth of Inflation:
The (Steinhardt's) implication being that a different group of authors could fine tune another inflationary scenario to fit another data set, and so on. That is to say inflationary cosmology is no longer disprovable by any observational data.
And yet there's an author of inflation (at 49:56) in the video I linked above who gives a testable prediction that, he says, would falsify inflationary cosmology. Sounds pretty unambigous to me.
Yes, it's an unambiguous claim that positive spatial curvature falsifies inflationary cosmology. However, here are 4 authors that discuss inflationary cosmology with positive spatial curvature.
https://www.researchgate.net/publicatio ... _Curvature
Yes, but are positive-curvature inflationary cosmologies also
multiverse models that lead towards infinitely many bubble universes?
I don't know. It simply supports the idea that another group of researchers can fine tune inflationary cosmology to fit any scenario, per the original claim.
However, eternal inflation does not disallow such universes to exist for the limited number of e-foldings in the linked study. If they then fade away to nothing, another region of the eternally inflating spacetime will go on to produce another one, and so on. That's the thing about eternal inflation - it produces all possible universes an infinite number of times.
I suppose it is possible to propose that there was inflation in the early universe, but that it never spawned new bubble universes,
No, that's not possible, for the reasons given by Steinhardt et al.
nor that our own local cosmic expansion itself could be one such expanding bubble.
What? If our bubble wasn't created by inflation then what was it produced by? (Or, have I misunderstood your "nor" clause, here?)
In that sense it is possible to retain an inflationary cosmology (which is merely inflationary in the sense that it proposes early and fast inflation mechanism), yet having no multiverse implications.
No, any inflation leads to eternal inflation - it's inevitable, for the reasons given by Steinhardt. That's the reason Steinhardt et al dropped the idea.
I am, somehow, less interested in the weight and convolutions of Einstein’s brain than in the near certainty that people of equal talent have lived and died in cotton fields and sweatshops. - Stephen J. Gould