In the last decade, parallel universes–a thought experiment once reserved for geeks on rainy (or sunny) weekends–has become something of buzzword, up there with dark matter and time travel in its capacity to captivate. It used to be that no one actually believed in parallel universes, they just thought it was cool to think about. Then something called string theory (or the ‘branes’) came around and pistol-whipped us with the notion of other dimensions wrapped into the fabric of our own reality. The shocks to the system didn’t stop and, in recent years, scientists have actually begun to look for physical evidence of the ‘multiverse’.
First, let’s identify the four possible modes of parallel universes:
Type 1 – The Infinite Universe
This model holds that the universe is infinite. Therefore, every possible configuration of matter must necessarily repeat itself at some point. This means that beyond the cosmic horizon of our universe–somewhere way WAY out there, a place we haven’t even received light from yet–there is a region of space exactly like this one, where exactly the same galaxies, solar systems and planets have formed.
Type 2 – The Inflationary ‘Bubble’ Universe
This type of parallel universe envisions countless bubble universes popping up and disappearing. This would mean that the beginning of our universe, the Big Bang, was just the creation of one bubble in a vast sea of inflating universes, which will eventually pop–or whatever universes do when their bubble juice becomes too unstable. Type 2 also includes the “brane” universe, which is an evolution of string theory.
Type 3 – The Many-Worlds Universe
This theory is borne out of the weird and wild world of quantum mechanics, but in the science fiction world it’s often identified as the “alternate history” universe. The Many-Worlds theory holds that every possible version of every possible event will happen in a different universe. Essentially, it posits quantum uncertainty as a kind of bifurcating tree of worlds; every time you make a choice, you’re branching off into a different universe. We find it kind of comforting imagining that everything that can happen will happen–then again, it’s also kind of horrifying.
Type 4 – Different Laws of Physics and Mathematics
The final type is our favorite, a truly bizarre notion that our universe is just one of an endless number of different KINDS of universes. The concept sort of harkens back to the bubble theory–countless numbers of universes existing within the same multiverse–except in this model, each one of these universes is wildly different, containing different laws of physics and different mathematical descriptions of reality. In one universe, matter never formed; in another, time flows in reverse. There could be a universe filled with wormholes, allowing intelligent life to travel around to different stars and galaxies. Or a universe that is one giant black hole…with a computerized brain at the singularity.
Last year, scientists made the shocking announcement that there may be impressions or “bruises” of other universes that have impacted ours. Roger Penrose at the University of Oxford and Vahe Gurzadyan at Yerevan State University in Armenia say that strange unexplained circles in our microwave radiation maps suggest other “bubble” universes may have collided with ours four times in the past.
Another scientific study published a year earlier, suggested there may be evidence of dark energy “antigravity” leakage from a neighboring universe.
The question we’re left pondering is whether it’s possible to visit any of these other universes, to cross over. It’s kind of a shoot-for-the-stars question (literally) when you consider that we haven’t even been to another planet yet. And even if we did cross over to another universe, we might wind up in the middle of a star, or maybe this new universe contains planet-sized bioforms that immediately gobble us up. Regardless, there’s no pressing need to abscond to a new universe right now, we still have plenty to do here.
But at some point in the distant future, our universe may in danger of succumbing to the great freeze, when the heat death of the universe is upon us (or whoever is alive). By this time, a post singularity civilization that is able to harness the power of a star or even an entire galaxy could direct all that energy into a single point, achieving ultimate Planck energy and actually tearing a hole in the space/time of our universe. Perhaps through this hole we could send a nanobot spore endowed with all the blueprints of human (or by this time, likely posthuman artificial intelligence) life and seed the new universe.
Or, crazier thought: what if the “bruises” detected in the cosmic microwave radiation map are actually the efforts of advanced aliens to break on through, beating us to the punch and trying to get the hell out of Dodge.