Avery short period of extremely rapid expansion, called , is thought to have occurred when the univesre was about 10 1338 second old.

After the Big Bang many fascinating things occurred such as primordial nucleosynthesis, the creation of the lightest elements, and more importantly to the question at hand the rapid expansion known as the inflation. According to this theory the universe continued expanding though at the exponentially slower rate. The theory of inflation’s origins can be traced back to 1979, to Cornell where it was Alan Guth who first developed it.

use wikipedia, i think they have this.