It should be noted that space experts are pretty clear about the nature of the universe just moments after the Big Bang, as it followed the basics of fundamental physics. However, some experts believed that during those initial moments, basic physical laws were somehow altered.

The Canadian researchers who took part in the study used this idea and assumed that the universe was always symmetrical and simple. They later tried to mathematically extrapolate the universe before and after the Big Bang. This research made them believe that the universe before the Big Bang was just a mirror image of the current cosmos.

However, in the previous universe, everything was reversed including time. Before Big Bang, time went backwards in the universe, and particles were antiparticles.

"Instead of saying there was a different universe before the bang. We're saying that the universe before the bang is actually, in some sense, an image of the universe after the bang. It's like our universe today were reflected through the Big Bang. The period before the universe was really the reflection through the bang," Neil Turok, a scientist at the Perimeter Institute for Theoretical Physics in Waterloo, Ontario told Live Science.

This is not the first time that scientists are envisioning the existence of a second universe before Big Bang. However, it was previously hypothesized that these universes were separate entities, but this research argues that it was just a mirror image of the current universe.

The new theory, which is laid out in a recent paper in the journal Physical Review of Letters, aims to preserve a rule of physics called CPT symmetry. In the anti-universe before the Big Bang, it suggests, time ran backwards and the cosmos were made of antimatter instead of matter.

This new theory is compelling, according to a news release about the new theory, because it would mean that the universe is filled with "very massive sterile neutrinos" that could explain dark matter, a mysterious material that is believed to make up much of the universe.

By the researchers' own admission, according to Physics World, many details of the new theory still need to be hammered out. But co-author Neil Turok, of the Perimetery Institute for Theoretical Physics in Ontario, argued in an interview with the publication that the new theory is a strong one because it relies only on known particles and fields, instead of assuming that new ones will be discovered in the future.

"There is this frame of mind that you explain a new phenomenon by inventing a new particle or field," he told Physics World. "I think that may turn out to be misguided."

This new theory can be also perceived in a different manner. For example, both these universes might have been created during the Big Bang, and they exploded simultaneously backward and forward in time. Some experts believe that more studies conducted using this theory will eliminate the weird possibility regarding the existence of multiverse or parallel universe.

Earlier, during the fourth season finale of Neil deGrasse Tyson's Star Talk TV show, legendary physicist Stephen Hawking had revealed that nothing existed before the Big Bang.