Before Professor Stephen Hawking passed away on March 14, he was working on a theory about what happened to our universe right after the Big Bang.
He worked on this theory with his colleague Professor Thomas Hertog and the two first presented the idea to Cambridge University during Hawking’s 75th birthday. It was the last paper Hawking worked on before his death a year later.
Two months after his passing, their paper on ‘eternal inflation’ has finally been published in the Journal of High Energy Physics.
The paper is based on the pair’s theory of eternal inflation. According to IFL Science!, after the Big Bang our universe experienced a few moments of intense acceleration expansion, known as ‘cosmic inflation’. In terms of eternal inflation, scientists believe most parts of our universe continue to feel its effects. However, some areas such as the visible universe, are exceptions to the rule.
Both Hawking and Hertog disagree with this theory. In a statement Hertog said:
The problem with the usual account of eternal inflation is that it assumes an existing background universe that evolves according to Einstein’s theory of general relativity and treats the quantum effects as small fluctuations around this.
However, the dynamics of eternal inflation wipes out the separation between classical and quantum physics. As a consequence, Einstein’s theory breaks down in eternal inflation.
It’s believed eternal inflation creates a multiverse from the Big Bang. So the regions where cosmic inflation has stopped become ‘pocket universes’ which has too much detail to be 3D – but lacks the quality of a 4D cosmos
Professor Hawking previously said in an interview:
We predict that our universe, on the largest scales, is reasonably smooth and globally finite. So it is not a fractal structure.
The usual theory of eternal inflation predicts that globally our universe is like an infinite fractal, with a mosaic of different pocket universes, separated by an inflating ocean.
The local laws of physics and chemistry can differ from one pocket universe to another, which together would form a multiverse. But I have never been a fan of the multiverse. If the scale of different universes in the multiverse is large or infinite the theory can’t be tested.
The approach Hawking and Hertog took to eternal inflation differed from other conventional means. They used string theory to work out relativity and quantum physics, as well as a holographic principle. This means all the information of our 3D universe can be encoded onto a 2D sphere.
Equipped with these tools the two were successful in tweaking eternal inflation. They transformed it into a timeless state, which makes a small collective of possible universes with no fractal multiverses to complicate matters.
According to IFL Science! Hertog is currently searching for the reason behind their eternal inflation interpretation but on a smaller scale. He hopes we can spot the consequences of their theory in the stars through our telescopes.
If we do hope to spot it one thing we should be on the lookout for are gravitational waves. It could provide crucial information in the next few decades which can prove or disprove the theory of eternal inflation.
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