Alright. So you’re stoned out of your mind and random thoughts are buzzing around your head. You feel like you’re in touch with other vibrations and other frequencies... other dimensions even. So now what? I’ll tell you. This is the moment to let your mind do some exercises in creativity, especially if you've enjoyed some cannabis. This powerful plant can provide increased focus, concentration and awareness, making it easier for you to think out of the box and to come up with new realizations. According to Honest Marijuana, this happens in the third phase of being high. This makes it the best stage for analysing, discussing, and well, basically going out there mentally. In that exalted state, is there a better subject to address than, well, I don’t know… THE UNIVERSE? I don’t think so. We'll help you get started with the three main theories about the structure in which our universe exists. Fasten your seatbelts and enjoy the trip!
Theory 1: We are part of a multiverse
The hypothesis of the multiverse is that our universe, which we generally consider to be all-encompassing, is not the only existing universe. Indeed, when time and space are infinite, there is an infinite number of universes, in which every possible event occurs an infinite number of times. For example, there is a parallel universe in which you are reading this article, but with green hair and a doughnut around your ear. Or one in which you wrote this yourself, on the wall, in custard. These variations are also called ‘daughter universes’.1 All these worlds together, with their infinite possibilities, are the multiverse. The first person to come up with this rad idea was Erwin Schrödinger, in 1952. According to Schrödinger, endless alternatives to events exist. Only they aren’t really alternatives because they all happen at the same time.2 In every universe, the constants and laws of nature are just a little different. This theory is linked to the 'anthropic principle': it is only logical that we perceive the universe as we perceive it, otherwise we could never exist. Our perception is related to our existence, we can’t know of the things we can’t perceive. In a multiverse, it makes sense that a universe like ours exists, because the number of possible universes is infinite.3
Evidence
That's a nice thought, you might think, but where's the evidence? That is a difficult one. Unfortunately, it is impossible for us to see the outer edges of our own universe, let alone beyond that. This is because our universe is bent, which means we are trapped in something like a fishbowl.4 Because the theory of the multiverse can’t be proven but can’t be falsified either - a bit like the existence of gods - some scientists say that the multiverse is not a legitimate research topic. It would be more suitable to talk about in terms of philosophy.5 The advantage of this is that you can ponder about it endlessly (what you are probably doing right now, in a parallel universe).

Theory 2: the bubble universe
Now that you wrapped your magical mind around this concept of multiple universes in endless time and space, you're ready for a connecting theory: the bubble universe. You probably know the Big Bang theory: from a single vacuum of great energy, the universe expanded at a high pace. A bit like a balloon. This process, which is still underway, is also called inflation. According to the theory of the bubble universe and endless inflation, however, the big bang did not give birth to one expanding bubble, but to a whole bubble sea. Each bubble with its own vacuum core. Because space-time has increased in different places at a different pace, the bubble universes can each have their own constants and laws of nature. Because of these other basic rules, these other worlds might be very strange in our eyes.
Evidence
Recently, astronomers have discovered a phenomenon that could be a clue to the existence of other bubbles. Staring at the stars, they observed a cold spot in space which could not be explained directly by the standard Big Bang theory. An exciting explanation is that the spot is caused by a collision between our universe and another bubble universe. This would be the first concrete indication of the existence of the multiverse and an indication that ‘the all’ looks like a cloud of freshly blown bubbles. How cool is that?

Theory 3: Our universe is a simulation
Hold on tight, because now we go nuts. What if our entire universe, as we know it, is a simulation? Just like in the movie The Matrix, everything we experienced would be a giant computer simulation created by a more developed intelligence. If so, can we find tangible evidence for this theory? In The Matrix, people can perceive some glitches - minor mistakes or repetitions in reality that we discard as an optical illusion or a déjà vu. It seems plausible that our endlessly complicated world (just look through a microscope) could not, as a whole, be made so detailed. Perhaps there are some shortcuts and approximations here and there? Perhaps it is possible for us to see these glitches every now and then if we look real closely?
Evidence
The problem of this kind of evidence is that any evidence we think we would find could be simulated. Thus, no substantive proof of the theory could be found. According to the famous astronomer Neil Degrasse Tyson, we must therefore not look for evidence in this direction. According to Tyson, it is quite likely that we live in a simulation if you assume that time is infinite. His thinking is as follows: in theory, it is possible that one day there will be a species capable of perfectly simulating a universe. If time is truly infinite, an infinite number of civilizations can create an infinite number of simulations. Even more so, if the simulation is perfect enough, the inhabitants of the simulation might even make simulated worlds of their own. Wow. Double wow.
The sky is the limit?
These are just some of the mainstream theories that are actually being discussed in science. If you take a moment to realize the endless possibilities concerning our place in the ‘everything’, it's almost arrogant to think that we live in the one and only real universe.
Hopefully, you'll have enough material to space out to for now. Want to read more? In the fantasy and science fiction genre, much has been written about the multiverse, also known as metaverse, quantum universe or parallel or alternative worlds, dimensions, realities or timelines. One of my personal recommendations is the book series The Long Earth by Terry Pratchett and Stephen Baxter. Have fun and safe travels!
Author: Sara de Waal
Notes
1 5 reasons we may live in a multiverse
2 David Deutsch, The Beginning of Infinity, page 310.
3 In een multiversum is een heelal zoals het onze niet meer dan logisch
4 Parallel Universes: Theories & evidence
5 Does the multiverse really exist?
Images:
Night Sky, Photo credit: Foter.com
Universe, Photo credit: European Southern Observatory via Foter.com / CC BY
Planetary Nebulas, Photo credit: Smithsonian Institution via Foter.com