Find out how much the universe grew by during the period of inflation

[AaronKnight]

Is it possible to find out how much the universe grew by during the period of inflation after the big bang?

 

[mikeph]

Not yet. Inflation is still just one theory to explain some cosmological features, and there is no evidence for it (yet- see gravitational waves and experiments investigating polarisation of the CMB).

You can calculate the minimum amount of inflation required by an inflation theory to give us the current flat universe, and I think that's about 60 e-foldings if I remember correctly (so a factor of e^60).

 

[Chalnoth]

Is it possible to find out how much the universe grew by during the period of inflation after the big bang?

The difficulty is that there is a distinct limit to how far back in inflation that we can possibly observe. Now, we still don't know precisely what inflation was. If we do discover the details of what it is, it is conceivable that that will come along with some specific statements as to how and when it began, which will immediately tell us how much it grew.

The most that we can do at the current stage is place some lower limits on how much it grew. Current estimates are around a factor of at least 10^30 expansion in each direction (though I'd have to look at the specifics).