WTF is … the multiverse? Along with the general excitement surrounding the announcement that astrophysicists may have found a way to confirm the “cosmic inflation” model of the early universe came a keen sub-debate: does this result imply we live in just one universe of a so-called “multiverse”. The Register doesn't have the requisite competency in …
So the theory goes:
http://www.nytimes.com/2014/02/16/opinion/sunday/is-the-universe-a-simulation.html?_r=0
For the TL:DR types: The universe is sooooo big that it inevitably contains beings with far more technological ability then we have. However, even at our level we build mathematical models and computer simulations. Therefore it's reasonable to expect that so do these super-beings. And since simulations are much easier to make than "reality" is, there are probably far more simulated universes than real ones.
One question that they might like to answer simulate would be: what would other universes look like? And one way to find out, would be to run some models. Hello!!!! here's one and we're in it.
Of course, this theory fades into infinity, as those super-beings are almost certainly inside someone else's simulation .. and so on.
"Hello!!!! here's one and we're in it."
Cogito ergo sum. That thought experiment isn't new, it's essentially what Descartes answered when he posited the same question - "how do I know I exist? How do I know it's not all a dream?". The conclusion was that he didn't, but he knows that something or someone has to be doing thinking and so it doesn't matter. Somewhere, in some form, he exists.
There are no clues to whether reality is real or fake.
"There are no clues to whether reality is real or fake."
I guess that's what Plato figured out with his cave analogy. To this we nowadays add the problems of perception and consciousness, in the sense our perception is bound up in our theories about optical and sound wave radiations impacting upon our eyes and ears, so we don't experience things entirely objectively at all - to do that would require our ability to perceive independently of the mental models we need to use to make sense of our perceptions.
The problem with the simulation idea is that even from inside the simulation you can observe information entering and leaving the simulation mediated by whatever device the simulation is being run on. Now you might posit black holes as being the out buses, but where is the incoming data stream? and wouldn't you expect either the cosmologists or the boffins at the LHC noting such an information flow? IANAP, just a Biologist but when you add up all the debris of an LHC collision the energies have to add up.
BTW this also deals with religious claims that god 'sustains the universe' such claims have real world consequences we should be able to see in the data. Absent those consequences we don't need the absence of dead pixels in the sky to indicate we are not living in a simulation or being dreamt by some deity a la Bishop Berkeley.
'The problem with the simulation idea is that even from inside the simulation you can observe information entering and leaving the simulation'
Are you sure? Have you ever been in a simulation? A simulation can be set up so that the recovery of information is not reflected in the simulation, and if the simulation is simulating correctly there is no need to input more information, in fact it is desirable not to as this would corrupt the simulation.
'And since simulations are much easier to make than "reality" is, there are probably far more simulated universes than real ones.'
Not necessarily. Simulations are often easier to make because they are "lite" versions of reality. A complex full-blown simulation may well be harder to make than the reality - it has to contain all the information in the real version, but not in the "native" format. A bit like running a virtual machine in computing - you need more computing power than the real version had, in order to do the same thing.
I've been reading about the multiverse for decades in Marvel comics. And Michael Moorcock books. Glad to see the boffins finally catching up.
Now if they could start watching BTTF we might all get our flying cars just a bit sooner. If they watch Dr. Who as well, then perhaps I might already have missed the announcement....
The odd thing about discussing the bounds of the universe is that it implies a boundary between what's inside and... something. Which is wrong, of course, because there is not even a vacuum beyond the bounds of the universe. A vacuum has existence, but the whole point of the universe is that it is all of existence, so there is no "beyond", there is no existence other than what is inside the universe, not even a vacuum, not even nothing! Confusing, much? Betcha.
Derivation of the word "Universe": 1325–75; Middle English < Old French univers < Latin ūniversum, noun use of neuter of ūniversus entire, all, literally, turned into one, equivalent to ūni- uni- + versus (past participle of vertere to turn)
So "uni" means all. There's your definition right there. It does mean all of existance.
It depends on what you mean by universe.
Max Tegmark's type I and type II parallel universes consider the area we can observe (the Hubble Bubble, things withing 13billionish light years) as our universe, and anything outside that is in another universe
1. This at least explains where MH370 has got to.
2. "you would eventually see pairs of particles and anti-particles (same mass, opposite charge) spontaneously pop into existence and annihilate each other, leaving behind a brief flash of energy" seems to also describe the workings of my bank account.
(The science is so beyond me this is the only way it makes sense).
Have they considered that instead of a multiverse, the 'missing' energy is simply the dimension of duration; such that the total energy of the system defines how long the universe will exist before it winks out of existence. With a bit of clever maths they might be able to predict how many billions of years we have left before it all collapses to a dot and the next Big Bang occurs.
If you consider that energy devolves into the triumvirate of observable dimensions of reality, space/time/matter, the universe is a whole singularity of energy split (or observed) through these three dimensions.
I don't follow why using all the "energy" for want of a better term would lead to the universe disappearing. I assume you're thinking of a halt to expansion and then a big crunch?
Current evidence suggests that we're accellerating, not slowing down, so no crunch in our future.
Penrose has a nice idea about heat death and minimal entropy being indistinguishable from maximal entropy that I find quite satisfying, I can tell you that we can probably work out when the heat death of the universe will occur.
I have no clue why you think energy and space/time are interchangable. I am sure I don't remember anything about that. Energy/matter can affect space/time, but the one isn't the other.
In other words, do you have a real hypothesis here or are you just trying to put a different spin on something you don't understand well enough?
I can tell you that we can probably work out when the heat death of the universe will occur
The current theory seems to be that it depends on whether nucleons (protons and neutrons) decay in the normal fashion - probably giving them a half-life of around 1034 years - or only via exotic mechanisms such as virtual black holes. In the former case, the universe bottoms out in around 10100 years; at that point it's essentially very close to equilibrium everywhere, a thin soup of photons, neutrinos, leptons, and the like.
Without conventional proton decay, we have a little more breathing room. In about 101500 years, give or take a day or two, light nuclei will have been transmuted into iron by quantum tunneling, and the same for heavy nuclei by fission and alpha-emission.
That's assuming false vacuum collapse or some other incident doesn't spoil the party first. After an FVC event,1 pretty much everything (like, oh, physical constants, fundamental forces, chemistry...) changes. Fortunately, per Coleman and de Luccia, a post-FVC universe would be unstable and collapse quickly, so there's no point in worrying about spilling that particular milk.
1Or more precisely, once you cross the threshold of the lower-energy vacuum bubble expanding from the nucleation.
The moment after the big bang seems understandable to me, and your description of a universe ending in "evaporation", makes sense, but I didn't read anything in your comment about the expansion of mass because of acceleration? I keep reading the universe is still expanding and accelerating even now. If this continues without abatement, the mass of the universe will increase to an infinite point and every particle will became so massive that it literally becomes a black hole and collapses out of this universe. Doesn't my drivel make any sense. I'm ignorant - enlighten me!
It is impossible for the human brain to comprehend infinity and a universe that goes on forever. Our experiences always are always bounded by something. Most humans even have trouble comprehending three dimensions as we are confined to the two (and a bit) dimensions of the surface of a planet. Throughout history, various theories have been proposed and then supplanted by newer ones as we have been able to better observe and understand our surroundings. No matter how much worms evolve in the future, they will never understand how a steam engine works. I think that we are all worms.
No matter how much worms evolve in the future, they will never understand how a steam engine works.
This is not necessarily true. If worms evolve to a degree similar to our own evolution, they may well understand steam engines. Or they may evolve in a completely different manner and end up oblivious to steam engines but with a better understanding of quantum physics than we can imagine.
And it's something we're all familiar with! It's called the present and exists everywhere in space as the difference between the past and the future. The Universe is expanding - into the future. Eternal inflation implies an infinite spatial Universe but still has bounds in terms of time.
If we have infinite space and energy, there are an infinite number of universes, some finite number of which would be able to attain inflation.
From this it easy to work out that the mean percentage of universes which did undergo inflation is zero, meaning that any inflationary universe you happen to observe is merely the product of a deranged imagination.
I really don't understand any of this, but then I probably don't need to. What would interest me is whether philosophy is keeping up with the science in providing any kind of rationisation of why we're here and what the point of us is.
I haven't had any religious belief for 40 years, but the Earth at the centre of the universe as the plaything of a community of gods, or the disappointing creation of a single deity, at least makes some sense, whereas the Earth as a piece of hardened mucus flying out from some 13 billion year old sneeze, isn't a concept I find very motivating.
No amount of philosophy will ever give you a satisfactory answer as to 'why', the truth is that life on this planet has evolved over millennia and is down to chance. Our existence is as fragile as the dinosaurs' before us and we have no real defence against an asteroid that will annihilate all of us past the gravity well of Jupiter, which is also likely to be the thing that sets said asteroid on course for us in the first place. Also, why would the universe as a physical representation of matter and energy be at all interested in giving you any motivation? You need to find your own motivation in life and I suggest you start with a study of the arts. As the great Tim Minchin once said (around September of last year when he accepted his honorary doctorate from the University of Western Australia), everyone should do a degree in art as it will help you find meaning where the is none...and I assure you, there is none.
everyone should do a degree in art as it will help you find meaning where the[re] is none
Because "finding meaning" is a category error. No one "finds" meaning in anything. People make meaning. Art, science, faith, and every other sphere of human endeavor have meaning in much the same way that fruit has pies. "Finding meaning" has the cart before the horse.
"providing any kind of rationisation of why we're here and what the point of us is."
Why do you care? You exist because you do. "I think, therefore I am".
Its up to you to choose what you do with your existence. It's up to you to define the why of your own existance. To party and have fun? To better the world? To better humankind? To save the world from humankind? To kill as many people as you can? To leave a legacy to the world? To spread your genetic makeup (i.e. have kids)? To drift through life aimlessly? To hear voices from a god? Only you can define that for yourself. And only you care, noone else cares why YOU exist.
" Earth as a piece of hardened mucus flying out from some 13 billion year old sneeze, isn't a concept I find very motivating."
If you need science or philosophy to motivate you as to your existance, you don't need a scientist or a philosopher, you need a mirror and a psychologist to find out why you need that.
What would interest me is whether philosophy is keeping up with the science in providing any kind of rationisation of why we're here and what the point of us is.
That's not what philosophy does. That's religion's job.1 Completely different realms.
Fortunately, these questions are pretty easy to answer. Why are we here? Because the earth is under a flow of energy and that gradient must be dissipated. What's the point? Whatever we make it.
1More precisely, it's the role played by mythology, which is the production of meaning to satisfy questions that apply to concrete existence but do not (at the cultural moment) yield factual answers.
I feel that this is the proper forum to relate the evidence we have gathered of the existence of at least one other parallel universe, right here!, right now! Whilst using our newly acquired Super Hoover® all manner of unknown materials and objects, the origins of which remain completely beyond our comprehension and understanding, were collected when cleaning beneath our teenage son's bed! So I am afraid to say that the evidence points to the existence of a multiverse right in our midst, in this house! The experience was very shocking and we are still reeling from the revelations we may have unearthed. Is there a number we should call?
Vacuums just seem a bit too well-behaved and sort of make/help/assist but do not hinder energy into becoming matter - and as for the transmission of light (well, you know, those wavelength sort of thingies) vacuums due a pretty good job.
Could not have specced up something to due the job better.
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"the scales are off by a hundred orders of magnitude"...“If inflation exists, the vacuum energy is contained on a larger scale than in our 'own' universe,”
Wholly crap! Dood, inflation sucks!
Seriously though, aren't a universe and a multiverse mutually exclusive? I mean if a universe is "all existing matter and space considered as a whole; the cosmos" then how can you have, presumably, multiple instances of it as a multiverse would imply? At least it's comforting to know that it's beer o'clock somewhen.
To accommodate all the random books in the Library of Babel postulated by Jorge Luis Borges, needed to include the works of Shakespeare should it be assumed such volumes arose entirely from chance.
If the fine tuned universe problem is genuine, cosmologists have a similar problem, but solving it using the assumption of an infinite energy singularity alone creating all possible universes doesn't seem any more plausible to me without much better evidence than the evidence we have .
The planet we stand on is of the right size, with right elements, on the right spot, around a stable non binary star, in a quiet part of a galaxy that didn't collide with another for billions of years. Add the moon creation event, the migrating planet cleaning the solar system of much of it's asteroid and comets (after the brought water in), and so on.
This quite random, and supposedly rare, combination of conditions happens to be able to sustain life.
As well, according to multiverse/bubbleverse theories, we live in some instance that just happens, by chance, to be able to sustain matter and energy (and by this way life as we know it) for long enough time.
I think the analogy is quite apt, but it's hard to tell if it's right.
Paris, because it's how I feel in this theoretical universe.
"Yeah... it's all fun and games until one morning you see dead pixels in the sky !"
Ha! The only indication of dead pixels would be very dark areas that we couldn't see but we could infer were there ... and, if the pixel was dead because it was electrically short, there would be a hard-to-explain flow of energy in that area ... oops I think I've just explained dark matter, dark energy and the existence of a higher entity ... now to send an email to gimme_a_nobel_prize.com! :-)
Well, 20 or so at least. Our visible universe is one of many such of course, or it would be different around the edges than in the middle. How many is an interesting question to ponder over a pint.
Say you go instantly to a galaxy on our horizon, then as far again, in an instant. This is a whole other visible universe on the edge of ours. It has the same cosmic background radiation, the same physical laws, the same structure from gross to fine.
Is it part of the same overarching Universe? Between the two there is no edge, no way to Balkanize them such that here one ends and another begins. To call them different universes makes as much sense as discriminating between the visible universe centered on London and the one centered on Beijing.
In the end it's all a matter of perspective. We are each the center of our own visible universe, sharing by proximity some part with each other in aggregate a greater whole.
OMG, that was the highest number of words that said close to nothing. I have no idea what vacuum energy is and the first I've heard of multiverse theory. It's funny how we humans are trying so hard to understand that which is probably in the long run unexplainable.
Here's a great question: if we could find out exactly how the universe was formed what would we do next?
You seem to be talking about theories that propose that outside our universe there are other things (that might be other universes), hence a multiverse. But in "quantum physics" (as mentioned in the title), the multiverse normally refers to the idea that all possible quantum statistical outcomes of an event actually exist together (rather than one of them being special and representing a unique reality).
So have you just conflated two rather unrelated ideas, or is there some more subtle connection between the two that I've missed? For example, is it being suggested that the existence of inflation is somehow the cause of quantum uncertainty?
The idea of the multiverse - as far as I understand it - is that there are an infinite number of parallel dimensions in which variations of this universe exist.
In some, Man never came to be because something kept that from happening. In other, closer variations, nuclear war happened after WWII. The possible infinites are unimaginable.
I do not see that this theory contradicts the "all possible quantum statistical outcomes of an event actually exist together". It all depends on your definition of "together".
>> In some, Man never came to be because something kept that from happening. In other, closer variations, nuclear war happened after WWII.
That sounds ok when you confine the examples to major events, but that must also include universes in which I just put 25 pieces of pasta on my lunch plate instead of 24. This starts to make eternal recurrence look quite reasonable.
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