What if the universe had no beginning?

Artist's rendering of the expansion of space. (Image credit: Shutterstock)
There was always well. Or maybe there wasn't. A new theory of quantum gravity suggests that our universe may have always existed.

Bruno Bento, a physicist at the University of Liverpool who studies the nature of time, said that "Reality has so much things that most people would associate sci-fi with fantasy."

He used a new theory on quantum gravity called causal set theory in his work. This theory states that space and time can be broken down into smaller chunks of spacetime. According to this theory, space-time is fundamental at some level.

Bento and his colleagues used the causal-set approach in order to investigate the origin of the universe. It was possible that the universe didn't have a beginning. Instead, it existed in the infinite past. The universe has only just evolved into what we now call the Big Bang.

Related: Big Bang to Civilization: 10 Amazing Origin Events

Quantum of gravity

The most frustrating problem in modern physics is quantum gravity. Two very effective theories of the universe exist: general relativity and quantum physics. Quantum physics has been able to describe three of the four fundamental forces in nature, electromagnetism, weak force, and strong force, down to the smallest scales. General relativity is the strongest and most complete description of gravity that has ever been created.

General relativity, despite its strengths and all that it offers, is not complete. The math of general relativity fails to produce reliable results in at least two places in the universe: at the center of black holes and in the beginning of this universe. These are known as "singularities," and are areas in space-time that our current laws of Physics crumble. They are mathematical warning signs that general relativity is falling apart. These singularities are where gravity is extremely strong on very small length scales.

Related: 8 ways to see Einstein's theory on relativity in action

To solve the mysteries surrounding the singularities, physicists will need to have a microscopic description and quantum theory of gravity. There are many options, including loop quantum gravity and string theory.

There's another way to understand space and time.

Causal set theory

According to all current theories, time and space are constant in physics. These two elements form the fabric of all reality. Two points can be as near to one another in space-time as possible. Additionally, two events can occur at the same time.

"Reality is so much more than what most people associate with sci-fi and fantasy." Bruno Bento

Another approach, known as causal set theory, sees space-time in a series of discrete chunks or "atoms". This theory would set strict limits on the distance events can exist in space and time. They can't be closer than the size the "atom."

Related: Can time be stopped?

If you look at the screen while reading this, it seems like everything is smooth and continuous. If you looked at the screen through a magnifying lens, you might notice the pixels that divide the space. You'd be able to see that two images are not possible to merge into one image.

Bento was excited by this theory of physics. Bento shared his excitement with Live Science.

Space-time can be described as a collection of discrete chunks, or "atoms", that are similar to pixels in a computer image. (Image credit to oxygen/Getty Images).

The beginning of time

The nature of time has important implications from the Causal Set Theory.

Bento stated, "A large part of the causal sets philosophy is that time passing is something physical. It should not be attributed either to an emergent illusion or something that happens within our brains that makes it seem like time passes; this passing, in itself is a manifestation of physical theory." A causal set is a set of atoms that grows one at a time, and then gets bigger and better.

Because singularities are not possible in theory, the causal set approach eliminates the Big Bang singularity problem. It is impossible for matter to be compressed to infinitely small points. They can only get smaller than the size a space-time Atom.

What does the universe's beginning look like without a Big Bang singularity? Bento and Stav Zalel (a graduate student at Imperial College London) took up the thread to explore what causal set theory can tell us about the first moments of the universe. Their work was published in a paper that was published on Sept. 24 in the arXiv preprint database. (The paper is yet to be published in peer-reviewed scientific journals.

Bento stated that the paper looked at "if a beginning must exist within the causal set approach." Classically speaking, a causal sequence grows from nothing to the universe we see today. This is according to the original causal set dynamics and formulation. Instead, we believe there wouldn't be a Big Bang to start the universe. The causal set would be infinite and past infinitude, so there's always more before.

Their research suggests that the universe could have had no beginning, but that it has simply existed forever. The Big Bang, as we see it, may have been a moment in the evolution this ever-existing causal set. It might not have been a true beginning.

However, there is still much to be done. It is not yet clear if this no beginning causal approach will allow us to develop physical theories that can be used to explain the complex evolution of our universe during the Big Bang.

Bento stated, "One could still question whether this [causal-set approach] can be understood in a reasonable way or what such dynamics physically mean in a broader context, but we proved that a framework was indeed possible." "So mathematically, it is possible."

It's simply a beginning.

Original publication on Live Science