Many Universe Question

Factual Questions
1

you know how a current theory is that quantum machanices requires many universes. that every outcome that can happen. does happen. and our universe is just one of the solutions every time.

that makes for a “sliders” type of multi universe sort of situation. alot of the quantum effects that happen ten trillion miles away probobly won’t change anything on earth. but other ones… must.

that means there is nearly unlimited other universes. does that mean that anything that could happen happens in one of them? or not?

is there a universe where I have blue skin? (probobly… some small change a billion years ago make blue pigment evolve and such)

what about one where I have a walrus head? what about one my name is joey joe joe shabadoo and I am the king god of the tree frogs and people named james??

how stupid of a universe does the many universe theory allow?
does the theory mean that anything that could possibly happen ever… HAS to exist in some universe? if every single instant… the universe is splitting into every single possible outcome of that minute.

is there a near infinite amount of me right now suddenly transforming into a carrot while hang glideing and singing beasty boys hits?

2

err… I hope someone can understand what I asked there. that was a really really poorly written post wasn’t it!?

3

I’m not at all qualified to answer this question, however I have heard similar things before and I eagerly await anyone with insight. The problem I have with this theory is as follows:

Let us say, hypothetically, that upon completing this sentence, my computer comes alive and swallows me. (pause) Well, it didn’t happen, thank God. But are we saying that in some other universe, everything else was exactly the same, but then my computer ate me? If so, shouldn’t I be thankful every minute of the day that I’m not in one of the infinite universes in which an inanimate object comes to life and eats me? After all, what are the odds that I happen to be in this one ideal universe, where nothing inexplicable like that occurs? Also, if my computer did eat me, how would science explain that happening? Aren’t we lucky also to be in a universe that is (so far) governed by certain laws of science that we’ve been able to catalogue (though primitively)? Or are we saying that an infinite number of universes exist, but they exist within the confounds of our physical laws?

Mind-boggling…

4

Owl, I’m not a physicist or astronomer. I have done a tad of both.

I am an writer and editor, and yes, you could have made your assumptions clearer.

There’s hardly one theory as to what multiple universes might be. The whole idea is a bit of a contradiction, since “universe” was supposed to mean “everything” in the first place.

The idea you’re talking about, which is that every time a certain choice happens, a new universe gets spawned, is more or less a cute idea developed by science-fiction writers, who wanted to put punch in their “alternate universe” ideas. When you stop and think, there’s no imaginable reason that a new heaven and earth should be created when you choose a Big Mac over a tofu burger.

There are more serious theories. People trying to explain how the “Big Bang” could cause something to exist that didn’t exist before, and so on.

5

No, because that wouldn’t be you. Do you have blue skin, or a walrus head? If you don’t, how could you call a creature with blue skin or a walrus head you?

You could even go beyond that. There are infinite other universes where you are exactly like you in this universe – where your DNA is the same, and all your experiences have been the same. But there are also infinite universes where you aren’t you, where your DNA is the same, but your past is slightly different.

As for Sliders, which went downhill as soon as they started jettisoning the original cast, the sliding device would have to have had a discriminator device built in. It would have to slide you to universes that were fairly close but not too close. Since there are infinite universes where Earth doesn’t even exist, it couldn’t be random. There are also infinite universes where everything is exactly the same on Earth, so you wouldn’t want to be too close or it’d get boring.

6

AFAIK, the concept was actually first developed by Hugh Everett in his 1957 PhD thesis. There are lots of sites on the subject.

Here is an introduction. Here is a more advanced look (and note this internal link).

7

[Being a schmuck]

Yes, Owl, it was poorly expressed. It could have been worse.
No, Partly, it is not a cute idea developed by science fiction writers. There is no more serious scientific theory than this. And your definition of universe is very 19th century.

[/Being a schmuck]

This will be a brief and an extremely sketchy explanation to your question. It has been discussed many times before here and there are literally thousands of web pages (most of it drivel) covering this subject. If you conduct web searches on all the terms I have bolded below, you will come to the realization after a few years of reading that what you are asking about concerns the fundamental paradox of Quantum Mechanics and addresses the question of what constitutes Reality. You will also come to realize that no one has the slightest idea what the correct answer is or how to conduct quantifiable research to determine the correct answer. Philosophy is apparently an un-American, or at least an unmanly, occupation. This stuff is in the area known as Metaphysics—the realm of First Principles. This is why most physicists ignore this whole problem altogether. It is left to the Sunday preachers (and the nut-jobs, if they are actually different people). If you wish to develop a theory of personal metamorphosis into carrots, you need only to make it mathematically rigorous. Otherwise, only your mother will pay attention to your theory. Needless to say, the Many-Worlds interpretation of quantum mechanics as developed by Hugh Everett has been developed and used (or at least supported) by some of the greatest physicists of the last century: Feynman, Gell-Mann, Hawking, DeWitt, Weinberg, Wheeler.
As quantum mechanics developed, it became apparent that mathematically and experimentally it was extremely accurate at describing what happens but does not have anything to say about the cause of what happens. Let’s take an extremely simplistic event. A neutron by itself decays into (falls apart or, more accurately, is replaced by) a proton, an electron, and an anti-neutrino. These three particles are necessary to conserve all the measurable properties of a neutron. For example, the neutron has no electrical charge so all of its decay products must add up to zero electrical charge. The proton has a +1 charge, the electron has a –1 charge, and the anti-neutrino has no charge.

This neutron decay almost never happens when a neutron is in an atomic nucleus because of the effects of the strong force on it from other neutrons and protons. A free neutron, however, decays under the influence of the weak force when one of the two down quarks making up a neutron becomes an up quark. But that is all background (and can be ignored) to the main event: a neutron decays with a half-life of about 15 minutes. A half-life is the amount of time in which a particle has a 50% chance of decaying. If you watch one neutron it may decay in 1 second or in a million years. If you watch a million of them, 500,000 will have decayed in 15 minutes. This statistical probability approach to describing the actions of particles is wonderfully accurate because there are so many of the little things in such a small space. When you apply this probability analysis to one particle, understanding what’s going on becomes suddenly very elusive.

Erwin Schrodinger developed a wave equation to successfully describe quantum events. Waves of what was not clear. Max Born was the one who determined that it was the probability of the event being described. If you are talking about a quantum particle’s location, the wave equation describes the probability of where it might be found. This is why you will sometimes here of a particle being smeared out. When you actually go looking for it, you find where it is and this is referred to as collapsing the wave equation because there is now the probability of 1 that the particle is where you found it and zero everywhere else. Now, before you went looking for it, the particle was not in any particular location. Not only did you not know where it was, but it was not in any particular place. This has been proven repeatedly by experiment. The classic one being the Double-Slit experiment. (Feynman has said the the Double-Slit experiment contains and clearly illustrates all the paradoxes within quantum mechanics.) It is the action of observing that crystallizes quantum events into the reality that we see all around us in the macro-world.

This is known as the Copenhagen Interpretation of quantum mechanics put forth by Niels Bohr. Now you may not like this. Einstein hated it. This is where his famous quote comes in: “God does not play dice with the universe.” But back to our decaying neutron. The 15 minutes are up and statistically we know it has had a 50% chance of falling apart. But it must be observed to collapse this probability into a certainty. And who observes the observer to collapse their quantum probabilities into a certainty of reality? Infinite regression sets in, and almost everyone quietly ignores the existential crisis popping up in a physics lab and instead applauds the new microwave oven developed upon the sound mathematical calculations of quantum mechanics.

Enter the many-worlds approach. The 15 minutes are up? It’s 50-50? Fine. There are now two universes: one in which the neutron decayed and one in which it did not. There is a little bit more to it but that’s it in a nutshell. No probability waves, none of Einstein’s not-yet-discovered foundation of reality, no Hidden Variables of David Bohm’s. Everything is nice and simple…except for the minor question concerning the mechanism for this proliferation of universes. As you can imagine, if every quantum event since the beginning of time increased the number of universes, there are quite a few of them now. But, hey, if you can have one universe out of nothing, why not an almost infinite number?

I can imagine a universe where events would end up with you being a hang-gliding carrot but not one where you would be morphing back and forth between yourself and a carrot. That would seem to me to go against the logical consistency of reality. Of course, that’s just my opinion. Why is the universe consistent? Why does 1+1=2 today, and again tomorrow? It seems to me it must or else there is no foundation for the existence of a continuum of reality.

If you would like to read an actual book, I suggest Gribbin’s In Search of Schrodinger’s Cat. It is a fairly unbiased and non-mathematical description of different interpretations of quantum mechanics. It’s probably 20 years old now but I should think mostly still current.

8

Ahem. This is the OP’s question:

“…that means there is nearly unlimited other universes. does that mean that anything that could happen happens in one of them?..”

This is straight science fiction. Yes, it’s true that there are quantum effects that could “explain” the operation of entirely conjectural universes, but that doesn’t mean they exist. It certainly doesn’t mean parallel universes are the most likely other universes to exist.

Parallel worlds were introduced into science fiction by J.H. Rosny in 1895. Not by Everett in a 1957 PhD thesis. (But I bet he read science fiction.)

9

However, there can’t be parallel universes that cover every possibility concievable, because it is a concievable possibility that there are no parallel universes.

Just thought I’d that in. :smiley:

10

Let me take a shot-in-the-dark at this one.

The Many Worlds hypothesis in qm or in relativity (for indeed, both are concerned somewhat with causality) can work in two ways.

One way is that all possibilities actually occur. The whole idea is that every event spawns alternatives that actually occur “elsewhere”.

The other way of thinking about it is that only events that can be observed spawn alternatives. Otherwise, for all practical purposes they don’t exist.

Consider, let’s say you travel back in time (which is possible in some GR models) and prevent yourself from going back in time. Well, in a closed causal universe that couldn’t happen, so there will be something which prevents you from doing it. In a many worlds idea you will simply enter into another description of the way the world is and simply travel on another world line on going back in time. There’s no way to tell if there were many worlds in “existence” before you arrived or if the alternative was created simply to accomodate the violation of causality. Since you can’t exactly go back and check, there’s really no way of telling.

However, the minute someone builds a time machine and gets into it, they’ll be able to tell whether or not the universe is self-consistent in causality. At least, that’s what Rich Gott told me when I took his class on General Relativity.

I don’t know that there’s much of a GQ left here.

11

There is also another theory that there can, at most, be something like 10^118 universes in existance. I don’t know how they got that number.

12

the thing about morphing. and computers eatting people. and the totally silly stuff.

the reason I ask about that is: every atom is moveing randomly unless at absolute zero. which I am not. beyond that, subatomic particals move by probiblity. 50% chance it will be here… 1% chance it will be there. .00000000001% chance it will move over to france.

but see… it CAN happen.

thats what I was asking about.

say that from atoms moveing randomly… there is err… 10000 moves that must occur correctly to magicly morph me into a walrus. (way more than that of couse… zillions and skillions would be needed of course by random motion) say the atom in my nose has to move right… then another one has to go up… and the third one has to go back an inch. ect ect a trillion zillion moves that have to work in order to make me a walrus.

in some universe… atom one moves right. then every possible way it could go… happens next… so follow it to the universe that has atom two going up… ignoreing all the others… then at the next split… find the universe that has the third one going back an inch.

could keep doing that… and in some universe just by random motion… stupid stuff like that must happen, right?

random motion and stuff is normally so small it dampers out. a single atom flying off my skin won’t be missed. but logicly shouldn’t every possible thing happen with some random motion… in some universe.

sitting here… alternate mes in other universes… are constantly explodeing… and vomiting ducks and growing tails and levitateing… and haveing a clone of jesus materializeing and doing a strip tease.

think of virtual particals. material just randomly appearing. single small little quarks and stuff. the chance of two appearing near eachother is like next to nothing. but thats the chance in one universe. in many worlds shouldn’t there always be one that has the mega unlikely chain of events of things appearing and disapearing and stuff.

all interactions big things like people have with matter is the average of the small things. averages tend to be… average. and so nothing odd goes on. but there is no law saying that with all the atoms in a wall moveing randomly… that they can’t all one instant all randomly go to one side. its just unlikely… REAL unlikely… but… what does likely/unlikely mean when every thing that can happen is happening?

13

Shalmanese… I think you might be thinking of the Skewes number which is the number conjectured that would be total number of possible atomic configurations (given 10^81 atoms in the universe) and assuming the Riemann hypotesis to be true. Unfortunately you’re number is way, way, way, way, too small.

Skewes number is approximately 10^10^10^34

14

“In an infinite universe anything that can happen does happen.” (I don’t remember who said that)

If there are an infinite number of universes and if it is possible for a person to spontaneously morph into a walrus then yes, there is a universe where owlofcreamcheese just turned into a walrus. In fact, it would be happening all the time in some universe somewhere. Of course, there are an infinite number of owlofcreamcheese that don’t turn into a walrus and an infinite number where owlofcreamcheese doesn’t even exist.

Sounds crazy yes but it helps you to get your head around what infinite really means. Any crazy crap you can dream up, as long as it is allowable in physics, can not only happen…it is happening.

It is possible (truly) that owlofcreamcheese will quantum teleport to Mars. The chances of this happening to all the atoms in his/her body simultaneously are exceedingly slim but they aren’t zero. So, if we have an infinite universe then somewhere this is happening to something at any given moment and this is in our universe (just to show you don’t even need to appeal to parallel universes for weirdness).

15

I suspect you’re confusing the definition of Skewes number with Hardy’s attempt to give an idea of how large it is.
By way of background, the number of primes less than n is famously approximated by the integral of 1/log(x) between 0 and n. To start with, this integral is larger than the number of primes, but in 1914 Littlewood proved that eventually the integral must drop below the other function. In doing so he assumed the Riemann hypothesis. Nor could he give any idea of how big n had to get before the cross-over would occur. Also assuming the Riemann hypothesis, Skewes (in 1933) found a bound - a value of n before which the integral had to be smaller. 10^10^10^34 is that upper bound and this is normally defined as Skewes number. (I presume Skewes actually could do a little better and this is the nearest “round” number to his actual bound, but, up here, who cares.)
According to Wells’ in his Penguin Dictionary of Curious and Interesting Numbers (Penguin, 1986):

This is however obviously an illustrative example rather than a definition.

There’s a nice old discussion of these issues in Littlewood’s Miscellany (ed. by Bollobas, Cambridge, 1953). Recent state of the art on the best bound on the cross-over is significantly better than Skewes bound - indeed there are better bounds that don’t even assume Riemann (Ribenboim, The Little Book of Big Primes, Springer-Verlag, 1991, p137).

Can’t say I’ve ever come across any suggestion that there’s any bound on the number of branches in any QM many-worlds interpretation.

16

GWF Hefel, you mentioned that the mechanism by which worlds would split in the many-worlds interpretation is unknown. In most serious formulations of the interpretation, however, I believe that there is not considered to be any mechanism causing the worlds to split (unless you count “the laws of physics” as a mechanism). Supporters of the MWI believe that the splitting of worlds follows inevitably from the dynamics of the Schrodinger equation which describes the time-dependent evolution of the quantum-mechanical wave function.

In my understanding, calculations suggest that, under certain conditions, the wave function of a system of particles can “decohere” into several independent states that do not interact with one another. These individual “slices” of the wave function are believed to correspond to different worlds. If I recall correctly, this decoherence occurs when two possibilities become separate enough that they do not share any possible futures. This corresponds roughly to macroscopic thermodynamic irreversibility, which in turn must accompany any process of measurement. However, I think that most of this has not been conclusively proven. It is very difficult to directly apply the Schrodinger equation to complex systems.

17

bonzer: Excellent redaction of my utterly confused post. Indeed, my wording left much to be desired. I was trying to get at what Skewes number was and a description of it all at once without blabbing on too much. It’s always unfortunate when I try to be concise and end up sounding like a ninny.

In any case, I did a search for Skewes number and quantum mechanics on Google (in hopes of finding the “many worlds” bound) and found this serendipty match that may be of some interest:

It seems that my pairing of Hardy’s description of the Skewes number and the many world’s model may have been unwarranted, but I found an interesting number yet!