If Mother Nature can create one Universe (ours), Mother Nature can create more than one universe – a Multiverse! The concept of a Multiverse, that there exists more than one universe, that is our Universe – perhaps an infinite number of them existing sequentially in time, or at one go in space, maybe both, is one of the hottest topics in current cosmology.
At the outset, there’s no law of physics (or even of God) that says that there can be (or must be) one and only one universe, our Universe.
Continued from yesterday’s blog…
The Multiverse Solves These Puzzles:
In reality, the idea of a Multiverse is more a logical outcome of current thinking and evolving understanding of various discoveries and trends in modern quantum/particle physics and cosmology, relative to being a tool used to explain actual data or anomalies or observations. The basic reason is that other universes, if existing, will tend to be so far away from us in time and/or in space as to exert no influence on what we observe; what data we collect. That’s not to say that the concept of a Multiverse, in one guise or another, can’t be used to help account for actual or philosophical anomalies.
For example, if the computer simulation of our and by extension any Multiverse is correct, that accounts for why there are apparently two sets of independent and incompatible software physics (quantum and classical) running the cosmos.
A computer generated Multiverse (lots of different computer generated simulations coupled with possible multiple copies of each) is in one sense a copout in that it can be used to explain anything. You can account for all data, all anomalies, all weirdness, everything natural and everything supernatural, everything logical and illogical, everything possible, and for that matter impossible. In a computer generated and simulated universe, you can indeed believe six impossible things before breakfast – ‘Alice in Wonderland’ or rather ‘Through the Looking Glass’ rules – OK? The existence of ‘impossible things’ does not of necessity invalidate the possibility however.
The concept of a Multiverse does provide the ways and means of examining other possible origins for our own Universe, which currently is (the standard Big Bang event) that first there was nothing and the there was something.
The there’s the Anthropic Principle: In order to explain why our Universe is so fine-tuned in terms of the laws and relationships of physics that make our universe life-friendly, it is necessary to either postulate one hell of an incredible luck of the draw, or a supernatural creator being who exists outside of space-time. The Multiverse solves the quandary by postulating that with so many universes in existence, with so many combinations of possible laws and relations of physics, that at least one universe, based on sheer chance alone, would be life-friendly. Since we can only exist in a life-friendly universe, the Multiverse helps explain our very existence, without having to resort to bucking incredible improbability or relying on the supernatural.
Double Slit Experiment: If you fire one photon, say one every minute, at two parallel slits with a photographic plate behind them, you might expect that plate to show, eventually, two blobs of light – one behind each slit, as each individual photon bullet passed through one, or the other, slit. However, what you get is instead a classic interference pattern – alternating light bands with dark bands. Why is this so? Rather, how can this be? Since the one per minute photons aren’t apparently acting like individual bullets, and yet since the only thing that can possibly cause classic wave interference is the presence of other, in addition to these one per minute photon bullets, photons, then where did these other photons come from? A logical explanation is that these photons are photons that enter or interact with our Universe from another parallel universe(s).
Time Travel Paradoxes: If time travel to the past is possible, and there is only one universe, our Universe, then paradoxes can arise. You can go back in time and murder your mother before you were conceived, which means you were never born, so you couldn’t have gone back in time and murdered your mother, which means you were born… However, if you travel back in time to another universe, part of the Multiverse, and kill what for all appearances looks exactly like your real mother, but is in fact a parallel universe copy or look-alike, then there is no paradox, because your real biological mother, in the universe in which you were born and raised, remains alive.
Variations on the Many Worlds Interpretation Theme:
There’s a variation that could apply to the Multiverse theme via the Many Worlds Interpretation of all things quantum. In the Many Worlds scenario, absolutely all possibilities are realized within any given ‘moment’ within the timeline. Each universe within the Multiverse has the additional complication (or added attraction) of having to jump through the Many Worlds hoops. So, to use a simple example, in one universe (A) within the Multiverse, you flip a coin and its heads. Coming to that fork in the road, a choice of heads or tails, that universe then splits into two, and you have flipped tails in the counterpart (B). Both possibilities have been realized. However, it is just as probable that there are enough universes within the Multiverse such that there was another universe (C) where you performed the identical flipping exercise and the coin came up tails (as in universe B). Postulating a Many Worlds Interpretation where there’s a split and you toss heads (universe D), well that’s already something that’s happened (in universe A) – not in a Many Worlds scenario, but in another actual physical universe. Therefore, what need for any Many Worlds interpretations at all?
I’m not however entirely sure this apparent equivalence will sit well with quantum physicists, because I’m not entirely sure this is what quantum physicists mean by the phrase ‘Many Worlds’ (indeed, lots of quantum physicists deny any such interpretation at all exists – it’s too big an ask for them). However, it seems to deal with the issue of That Cat! In two separate physical universes you have Schrodinger’s Cat (in the box which has been constructed to have a 50/50 chance of killing it within one hour) experiment. Identical cats; identical setups; identical observers (and they can be identical because the fundamental bits that make them all up are identical – all electrons (neutrons, protons, etc.) are 100% clones of each other – absolutely identical). In one universe, the observer observes the cat alive after one hour; the other universe, well it’s the demise of the feline. Neither universe has to split into two to cater for both possibilities of a living cat, and a dead cat. All possibilities have been exhausted without resorting to the requirement of a Many Worlds either/or split.
While I have little difficulty coming to terms with an infinite (or as close to infinite as makes no odds) number of universes (the Multiverse) that have collectively existed since the get-go in order to cater for all possibilities, I have some trouble coming to accept the idea that (Many) Worlds are created in an ongoing manner, as spin-offs, in response to evolving events that require this choice or that choice or the next choice. The difficulty, which I’ve never seen addressed in any books I’ve read on the subject is, where does all the additional matter/energy for the extra world – actually universe - come from? If a whole new universe is created to allow for the existence of both a cat that’s alive and a dead cat (in that cat-in-the-box thought experiment), that additional universe (to cater for the other option) seems to be a free lunch – something created from nothing. That seems to be a violation of the conservation of matter/energy. That’s much too big an ask for me to swallow! Therefore, I vote solely for the Multiverse, which because of the sheer numbers involved, allows for the incorporation of the Many Worlds Interpretation as a bonus. The only real difference I can see between the Multiverse and the Many Worlds Interpretation is that with Many Worlds, the outcomes (all possibilities realized) is certainty; with the Multiverse it’s only probable or possible.
Further recommended readings:
Carr, Bernard (Editor); Universe or Multiverse?; Cambridge University Press, Cambridge
Gribbin, John; In Search of the Multiverse; Allen Lane , London ; 2009:
Kaku, Michio; Parallel Worlds: The Science of Alternative Universes and Our Future in the Cosmos; Penguin Books, London
Rees, Martin; Before the Beginning: Our Universe and Others; Free Press, London
Vilenkin, Alex; Many Worlds in One: The Search for Other Universes; Hill & Wang , New York
Wolf, Fred Alan; Parallel Universes: The Search for Other Worlds; Simon & Schuster Paperbacks, New York
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