# Inflation Rate question.

1. Jun 21, 2010

### Dav333

Was reading that shortly after the BB, the universe blow up by a factor of 10 to the 50 in 10-33 seconds.

What does 10 to the 50 mean in terms of distance & size? All i know is its a large number.

2. Jun 21, 2010

### bapowell

This is the factor by which physical distances grew. If you painted grid marks on the universe before inflation such that the distance between the points (0,0) and (1,0) was, say , 1 meter, then after inflation (during which the universe grew by at least a factor of around 10^30), the physical distance between these points would be equal to the amount of expansion -- at least 10^30 meters. Mathematically, the quantity that grows during inflation is the scale factor, a(t), which relates physical and comoving distances:

$$d_{physical} = a(t)d_{comoving}$$