Professor Stephen Hawking wrote one final paper which is published posthumously. In this new paper, Hawking and collaborator Professor Thomas Hertog conclude that our Universe sprung from a larger state or “multiverse” that is not infinite.
Let us understand what this is all about by stepping back about 13.7 billion years in time. In these early days there is various evidence that our young Universe experienced a rapid period of growth called “inflation.” A very short time later, the inflation stopped and calmed down into the more gentle mode of expansion plus acceleration we see in our Universe today. But what is the situation beyond our Universe, in the multiverse, and how does it behave?
The prevailing idea is that inflation is a normal attribute in the multiverse, such that the multiverse is expanding all the time at exponential rates in state called “eternal” inflation.
From time to time, a universe such as our own emerges, and potentially even an infinite number of universes arise each with a different set of physical laws. But Professor Hawking was never a fan of the multiverse.
Hawking and Hertog set out to understand better this significant problem on the starting assumption that relativity physics was not important in the early periods of inflation. As such, they were justified to consider that only quantum theory was the dominant physics. They then introduced the approximation that the multiverse is empty, meaning that it has no matter or energy. They went on to impose a shape of this larger entity, and removed the dimension of time from their equations altogether, as time has no meaning in a state not subject to relativity physics.
Their conclusion is that we still live a multiverse, but it is no longer infinite with infinite physics and infinite possibilities. But, as Douglas Adams tells us, it is still “mind-bogglingly big.”
