Summary: Perhaps our universe has always existed — and a new theory of quantum gravity reveals how that could work.
Original author and publication date: Paul Sutter – October 13, 2021
Futurizonte Editor’s Note: We can’t understand how the universe may have a beginning. We can’t understand either how the universe may have no beginning.
From the article:
“Reality has so many things that most people would associate with sci-fi or even fantasy,” said Bruno Bento, a physicist who studies the nature of time at the University of Liverpool in the U.K.
In his work, he employed a new theory of quantum gravity, called causal set theory, in which space and time are broken down into discrete chunks of space-time. At some level, there’s a fundamental unit of space-time, according to this theory.
Bento and his collaborators used this causal-set approach to explore the beginning of the universe. They found that it’s possible that the universe had no beginning — that it has always existed into the infinite past and only recently evolved into what we call the Big Bang.
A quantum of gravity
Quantum gravity is perhaps the most frustrating problem facing modern physics. We have two extraordinarily effective theories of the universe: quantum physics and general relativity. Quantum physics has produced a successful description of three of the four fundamental forces of nature (electromagnetism, the weak force and the strong force) down to microscopic scales. General relativity, on the other hand, is the most powerful and complete description of gravity ever devised.
But for all its strengths, general relativity is incomplete. In at least two specific places in the universe, the math of general relativity simply breaks down, failing to produce reliable results: in the centers of black holes and at the beginning of the universe. These regions are called “singularities,” which are spots in space-time where our current laws of physics crumble, and they are mathematical warning signs that the theory of general relativity is tripping over itself. Within both of these singularities, gravity becomes incredibly strong at very tiny length scales.