Stephen Hawking’s final research paper that he co-authored with Professor Thomas Hertog is published finally. The paper was submitted just ten days before Hawking died. In this paper, he explained a new theory that explores the possibilities of multiverses.
According to the report of the University of Cambridge, it explains that the universe is a lot more simple and finite when compared to what many existing theories on the big bang. Hawking’s final paper has solved the puzzle by drawing on new mathematical techniques developed to study another branch of physics called string theory. The analysis suggests that there can only be universes that have the same laws of physics as our own.
However, the new paper argues that the concept eternal inflation to explain the events that followed the big bang is just wrong.
To understand what the professors mean when they say eternal inflation, consider what one existing theory on the big bang is. The Cambridge report mentions that modern theories on the big bang predict how the universe came to be with a “brief burst of inflation” that happened a fraction of a second after the bang itself which in turn kicked off the exponential expansion of the universe. The belief is that once this process started, it never really stopped. Quantum effects can simply keep this inflation going forever in some parts of the universe, making inflation eternal in the overall picture. However, there exist certain pockets like the one where our observable universe is and it just so happens to be a hospitable one where inflation has ended and stars, galaxies, and worlds formed.
“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,” said Hertog.
“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.
“We predict that our universe, on the largest scales, is reasonably smooth and globally finite. So it is not a fractal structure,” said Hawking.
Hertog says that this approach could help physicists in future to work on developing a complete theory that explains the entire universe and how it really came to be.
“The laws of physics that we test in our labs did not exist forever. They crystallized after the Big Bang when the universe expanded and cooled. The kind of laws that emerge depends very much on the physical conditions at the Big Bang. By studying these we aim to get a deeper understanding of where our physical theories come from, how they arise, and whether they are unique.”