# Cosmic inflation and space flatness

I am new here, an avid Physics reader, but have lots of questions and doubts on which I'd like to get the help of a pro physicist. Here goes some about the theory of Inflation:

a) after the first expansion (which lasted like 10^-38 secs), how big did the Universe get?

b) why such a irregular rate of expansion, one that takes almost 0 time and another that takes 13B years?

c) If the universe is flat, how come space time is warped around masses like the Sun?

d) If the duration of inflation was so infinitesimal, could it have been enough to allow that tiny region of space-time to come to an equilibrium at all as far as temperature and distribution was concerned? The speed of light is fast but given small enough time, it's not fast enough to cross the distance in that tiny area.

e) Also, was Eisntein's GR valid at all under those extreme circumstances?

• You should be aware that the whole concept of inflation is questionable. Some physicists reject the idea. – garyp Apr 26 '16 at 2:47

a) During the period of inflation the distance between two separated points in the Universe increased at least $e^{60}\approx 10^{26}$ times. The exact minimum depends on the specific model, and there is not an upper limit as far as I know (it could have expanded $e^{100}$ or $e^{1000}$ times).