Physicists suggest there’s an ‘anti-universe’ behind ours

A team of scientists from University of Waterloo have come up with an exciting new theory that explains the origin of the universe, its expansion, and the presence of dark matter. It involves the existence of a mirrored doppelganger called an ‘anti-universe’ where time runs backwards. And it might even be testable.

The big idea: What if the universe were a physical object? Current thinking says the Big Bang exploded the universe into existence and it’s been expanding ever since.

But the Waterloo team’s work imagines the universe as a space in which the Big Bang occurred. It disputes the long-held scientific notion that the Big Bang was immediately followed by a period of rapid inflation.

If instead, our universe were paired with an anti-universe, a period of rapid inflation wouldn’t have been required after the Big Bang, as particles would have formed naturally over time.

This would allow the entire universe to follow a concept known as CPT symmetry, something that’s normally only applied to particles and their interactions.

As LiveScience’s Paul Sutter recently wrote:

Physicists have identified a set of fundamental symmetries in nature. The three most important symmetries are: charge (if you flip the charges of all the particles involved in an interaction to their opposite charge, you’ll get the same interaction); parity (if you look at the mirror image of an interaction, you get the same result); and time (if you run an interaction backward in time, it looks the same).

This fundamental symmetry is given a name: CPT symmetry, for charge (C), parity (P) and time (T).

Sutter, an astrophysicist, goes on to explain that this particular theory imagines the universe as a physical object that obeys CPT symmetry.

This means you could flip the universe’s charge, mirror it, and run it backwards, and it should still act the same way it does in its current state.

Here’s where things get fun: In order to support this idea, there’d have to be an anti-universe that meets those three fundamental qualifications.

From what the research appears to indicate, it’d be a backwards-running reverse universe that, essentially, exploded in the opposite direction from ours when the Big Bang occurred.

According to the researchers, the doppelganger anti-universe would potentially have neutrinos in it that were the CPT-symmetric opposite of our universe’s.

The reason that’s important is because the presence of “right-handed” neutrinos would offer up a tidy explanation for dark matter (all of the neutrinos in our universe are referred to as “left-handed” because of the direction of their spin).

Neural’s interpretation: This is super cool.

Imagine our universe as a soap bubble. Now imagine there’s a photo-negative soap bubble connected to the one we live in.

Maybe the Big Bang was just compressed “everything” that gently released all the matter and antimatter into both of those bubbles without popping either. In the anti-universe — the bubble our universe is attached to — time runs backwards and particles expand in the opposite direction. The significance here is that the particles move towards the edges, but neither universe inflates.

The most interesting thing about this whole theory is that we may be able to actually test it one day. The scientists ran “numerous simulations” to confirm many of the assertions in their theory. But the ultimate indicator of whether the universe itself maintains CPT symmetry may come from further study at the edges of quantum astrophysics.

Obviously, humans can’t just zoom out beyond the boundaries of our universe to see if there’s something behind it. But, if it turns out that right-handed neutrinos exist, and we can solve the mystery of dark matter in our own universe, we may be able to demonstrate empirical evidence for the anti-universe’s existence.