By Mathew Goldstein
According to the theory of cosmic inflation, our universe started from almost nothing, borrowing the required positive energy from a growing, negative energy,
gravitational field as a result of the large negative pressure of the tiny, initial, inflating substance. In a fraction of a second (less than about 10^-35 seconds) our universe doubled in size about 260 times. Then this period of "Big Bang" inflation ended.
One of the predictions of inflation is that the cosmic microwave background radiation will contain an imprint of gravitational waves. This is because quantum fluctuations during inflation will generate gravitational waves. To celebrate the recent discovery of the predicted cosmic microwave background B-mode polarization (and to promote his new book), Max Tegmark has placed the inflation chapter of his new book, Our Mathematical Universe: My Quest for the Ultimate Nature of Reality, on the internet. This is the up to date version of the first part of the first chapter of the obsolete book commonly referred to as the bible, with inflation now assuming the role formerly attributed to God, and it is free, so take a look. It explains why the Big Bang only makes sense if inflation is true, that inflation makes multiple predictions which have been demonstrated to be true, and the implications of inflation for cosmology (inflation is eternal, therefore we live in a multiverse).