On March 13 of this year, the news arrived that the famous professor Stephen Hawking had passed away due to his advanced age. However, although he ceased to exist, his works are still published. Now, an investigation sent to review only 10 before his death, has just been published today in the Journal of High-Energy Physics and can change the concepts that are held about the multiverses.
Stephen Hawking’s latest theory on the origin of the universe, developed in collaboration with Professor Thomas Hertog of the Catholic University of Leuven, predicts that the universe is finite and simpler than current studies on the Big Bang.
Current theories suggest that the universe was created in a brief explosion, for a fraction of a second after the Big Bang, when the cosmos expanded rapidly. It is believed that, once inflation occurred, many regions never stopped growing and that, due to quantum effects, this phenomenon is eternal. Therefore, the observable part of our universe is a minimum portion where the process has ended and stars and galaxies have formed.
“The usual theory of eternal inflation predicts that our universe is like an infinite fractal with a mosaic of different small universes separated by oceans that grow,” Hawking said in an interview last year.
“The laws of physics and chemistry may be different between one universe and another that, together, form a multiverse, but I have never been a champion of the multiverse, if the scale of the different universes in the multiverse is large or infinite, you can try it, ” the famous professor added.
The new research
On the other hand, in the newly published research, the two physicists claim that this theory of infinite expansion is wrong. “The usual problem with this theory is that it assumes the existence of a background universe that evolves according to Einstein’s general theory of relativity and treats quantum effects as small fluctuations around it,” says Hertog. “However, the dynamic of eternal expansion sweeps away the separation between quantum and classical physics,” he adds.
On the other hand, in the same note published by the ERC (European Research Council), the deceased professor predicts that “our universe, on a large scale, is reasonably smooth and globally finite. So it’s not a fractal structure. ”
Hertog and Hawking used their new theory to derive more accurate predictions about the global structure of the universe. Their results could have implications for the multiverse paradigm. “Our findings imply a significant reduction of the multiverse to a much smaller category of possible universes,” say physicists.
Hertog plans to study this theory at small scales that are within the capacity of our space telescopes. He believes that primordial gravitational waves are the most promising ways to test the model. The expansion of the universe from its origin means that these gravitational waves would have a very long wavelength, beyond the reach of our current LIGO detectors. But they could be detected by the predicted European space observatory of gravitational waves (LISA) or by future experiments of measurements of the cosmic microwave background.