The idea that we might be living in just one of an infinite number of universes has been fodder for scientific debate and sci-fi movie plots for a long time, but coming up with evidence to support the theory has been hard to come by. Now, researchers have discovered something in space that they can't quite account for, and one of the possible explanations is that -- are you sitting down? -- Our universe actually bumped into a neighboring, parallel one.

When gazing into the heavens, scientists spotted what they refer to as a "cold" area of space. It was observed some time ago, and explaining it proved difficult, but a 2015 study suggested it was merely an area of the universe in which the number of galaxies is dramatically lower than the rest. Unfortunately, subsequent investigations couldn't support that finding, and a new study by Durham University suggests the slim possibility that it's actually evidence of parallel universes is still on the table.

The multiverse theory hinges on the idea that all possible outcomes of any given scenario are all playing out at the same time in a layered reality of which we are only experiencing one layer. 

It's a wild idea that has a foundation in quantum mechanics, but it's also entirely unproven.

As the study states, the researchers believe the mysterious cold spot, while still totally unexplained, could actually be "the remnant of a collision between our universe and another 'bubble' universe during an early inflationary phase." In short, if the idea is correct, our early universe collided with another young universe early on, causing something of a "bruise" which we are able to observe today.

“Your theory is crazy, but it's not crazy enough to be true,” said the great Danish physicist Niels Bohr. Enter Sir Roger Penrose. Correlated noise in the two LIGO gravitational-wave detectors may provide evidence that the universe is governed by Conformal Cyclic Cosmology (CCC) which assumes that the universe consists of a succession of aeons, “the boundaries of infinity,” says Penrose of the University of Oxford. “The Big Bang was not the origin of our universe,” he observed. Penrose proposes that there was an aeon before the Big Bang. The apparent noise is actually a real signal of gravitational waves generated by the decay of hypothetical dark-matter particles.

These particles were predicted by CCC from a previous aeon that can be seen in the cosmic microwave background --electromagnetic radiation left over from an early stage of the universe in Big Bang cosmology. Penose argues that a significant amount of this noise could be a signal of astrophysical or cosmological origin – and specifically CCC. View this brilliant, beautifully produced interview with Penrose...

Physicists at the Niels Bohr Institute, writes Hamish Johnston, editor of physicsworld.com, pointed out that some of the noise in the two LIGO detectors appears to be correlated – with a delay that corresponds to the time it takes for a gravitational wave to travel the more than 3000 kilometers between the instruments. First proposed over a decade ago by Penrose, CCC assumes that each aeon begins with a big bang and proceeds into an unending future in which the universe expands at an accelerating rate. As this expansion becomes infinitely large, Penrose argues that it can be transformed back into the next big bang.

Penrose, Johnston writes, says that a “reasonably robust implication of CCC” is that dark matter consists of particles called erebons – the name deriving from the Greek god of darkness Erebos. As dark matter goes, erebons are extremely heavy and have masses of about 10–5 g. This is roughly the Planck mass and on a par with a grain of sand and about 22 orders of magnitude heavier than a proton. When an erebon decays, Penrose states, it deposits all its energy into a gravitational wave frequencies well above the detection capabilities of LIGO, and would be detected and recorded as near-instantaneous impulses that could be mistaken for noise rather than a signal from the birth of the cosmos.