*t*, it would be an amazingly fast process. Lets see about this. The duration of cosmic inflation Δ

*t*is constrained by particle physics. Reheating, which is the end of inflation, also called “Big Bang”, must happen before the so called electro-weak symmetry breaks at around 10

^{-12}seconds in cosmic time.

Cosmic time is here back calculated and expressed relative to a certain, convenient time scale. It does not imply a metaphysical

*t*= 0 moment where time itself was created. Below zero, there may be

*t*< 0 as usual. Before inflation, there may be nothing but a so called “de Sitter phase”, which is in a certain sense the pinnacle of boring as far as exciting space-times go.

All we need to know is that inflation happens somewhere between

*t*= 0 and reheating at

*t*=

*t*

_{reheat}, and so its duration Δ

*t*is about the same size as its endpoint

*t*

_{reheat}. Alright then, let us assume a small Δ

*t*to get a very fast inflation. Let us make it 10

^{20}times faster than the limit from particle physics: After only Δ

*t*~

*t*

_{reheat}= 10

^{-32}seconds, inflation is already finished.

The relevant time in fundamental space-time processes is the Planck time

*t*

_{P }of about 10

^{-43}s. Therefore we have

*T*/

*t*

_{P}= 10

^{-32}/10

^{-43}= 10

^{+11}fundamental units of time to accomplish 260 doublings. If we were to imagine fundamental volumes (microscopic boxes of space) multiplying like bacteria, every generation has 10

^{11}/260 ~ 10

^{9}time steps!

*Multiplying E. coli bacteria serve as a toy model of cosmic inflation.*

10

^{9}human heartbeats are equivalent to about 10 to 100 years. Not exactly bunny speed. And do not forget, we could have assumed Δ

*t*much longer, and then 100 years would turn into many times the age of the universe.

**Straw-man:**“Who knows what the size of the Planck time really is. And you forgot a factor of 2 somewhere. And the picture with the bacteria multiplying – are you some sort of crack pot or what? Cosmic expansion does not expand into an outside space like a culture of bacteria in a Petri dish! Give me string theory or something else I can feel important with in public! And is it or is it not faster than light?”

I will get into all this in the next post.

## Comments