2 years ago (14/03/21) | 500 Views |

# Stephen Hawking’s last Theory

Stephen Hawking died on March 14, 2018. About a month and a half later, on May 2, his research paper was published in the Journal of High Energy Physics. The study, co-authored with Thomas Hartog, a professor of cosmology at the Catholic University of Leuven, sheds light on new theories about the origin and evolution of the universe. In July 2018, on Hawking’s 75th birthday, Hartog discussed the new theory at a conference at Cambridge University.

The pre-evolutionary theory of the universe is the theory of eternal inflation. In the light of this theory, the universe goes through a periodic exponential inflation within a fraction of a second after the **Big Bang**. This process then slows down and the energies are converted into matter and radiation. However, experts believe that although inflation has started, it has never stopped everywhere.The idea is that in some parts of the universe, the quantum effect will cause bubbles to swell permanently and overall, so swelling is permanent.

In light of this, our observable universe is a habitable pocket of the entire universe. Where inflation stopped and stars and galaxies were born.Inflation of other bubbles in space is causing the emergence of an infinite number of universes and multiverse. According to this theory, the universe we observe is just one such bubble.

*Visualization of the swollen universe; Over time, the evolution of the spatial universe has continued through bubbles in the entire universe. (A. Lind / Stanford University).*Hawking noted in an interview, “According to conventional theory, the entire universe is like an infinite fractal, with mosaics of pocket universes created in different places. These are separated by an ocean of inflation. Locally, the formulas of physics and chemistry can be different in different pocket universes, and the sum of these forms the multiverse.But I was never a fan of Multiverse. If the scale of the universe is different or infinite in different pockets of multiverse, then this theory will not be testable. ”

**In the new study**, Hawking and Hartog point out that the theory of perpetual inflation at the origin of the universe is wrong. One problem with the inflation theory is that it envisions a background universe that develops according to Einstein’s general theory of relativity, and quantum effects exist as small deviations. However, the dynamics of perpetual inflation fail to distinguish between classical and quantum theories, making it difficult to establish Einstein’s theory.

According to Hawking, the universe is quite smooth and finite overall. They interpret their theory according to string theory. String theory is a branch of theoretical physics where gravity and general relativity are integrated in the light of quantum theory and are seen as vibrating strings.These tiny vibrating fibers are considered to be the structural unit of the universe. According to their idea, the universe could be imagined as a three-dimensional hologram that could be mathematically projected onto a two-dimensional screen.

Hawking and Hartog established a special variant of this theory of holography and distinguished ‘time’ as a dimension from perpetual inflation. As a result, the theory of perpetual inflation no longer has to depend on Einstein’s theory. In their new theory, perpetual swelling is prematurely bound to a spatial surface by timeless.”In the evolution of the universe, we have reached a point in time where the concept of time has become unnecessary,” Hartog said.In 1983, Hawking and another physicist, James Hartl, co-founded the “no boundary theory”, known as the Hartl-Hawking theory.Hartak said, “The Boundless Theory had the idea that if you go back in time and reach the starting point of the universe, you will find the universe as a tiny sphere. However, this new study takes a slightly different approach. Now we want to say that in the past the universe had a boundary.

Hawking and Hartog used their new theory to make reliable assumptions about the overall structure of the universe. According to their theory, the universe is much simpler and more finite than what was previously thought to be a complex infinite and fractal structure according to the previous perpetual inflation theory. If the validity of this theory can be confirmed by other experiments, it will lead the idea of multiverse to a completely different direction. This will make the multiverse theory more accurate and useful for testing.

**References**:

01. S.W. Hawking and Thomas Hertog. ‘A Smooth Exit from Eternal Inflation?’’ Journal of High-Energy Physics (2018). DOI: 10.1007/JHEP04(2018)147

02. https://www.sciencealert.com/stephen-hawking-s-last-physics-paper-theory-on-eternal-inflation-multiverses

03. https://www.cam.ac.uk/research/news/taming-the-multiverse-stephen-hawkings-final-theory-about-the-big-bang