# Why is there more than one Universe?



## Raain (Jan 3, 2012)

I started a thread were I asked how it would be possible to still believe in God if the Omniverse was never created.

http://personalitycafe.com/critical...-god-if-universe-eternal-never-created-7.html

Only I don't entirely understand why Scientists think there that there is or could be multiple universes and or an Omniverse.

So I am hoping to attract the physics/science minded people on this section who maybe couldn't care less about the question in that last thread to answer the question below:

*What argument or evidence do scientists use to hypothesise the existence of multiple universes or the Omniverse?*

Thanks.


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## bigtex1989 (Feb 7, 2011)

The multiverse hypothesis is an exercise in pure unadulterated logic. It goes like this.

1. The universe contains everything (by definition)
2. The universe is expanding
3. The universe must be expanding into something
4. The universe can not contain everything
5. There must be something outside the universe
6. Other universes exist
7. An infinite amount of universes must exist

That is one of many possible logical arguments based on data that could lead to a multiverse hypothesis. Also, scientists don't need evidence to make a hypothesis. You need evidence to support one. At present, there is no such evidence, which is why we don't really teach it in schools XD


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## dizzycactus (Sep 9, 2012)

bigtex1989 said:


> The multiverse hypothesis is an exercise in pure unadulterated logic. It goes like this.
> 
> 1. The universe contains everything (by definition)
> 2. The universe is expanding
> ...


That seems to be a slightly flawed assumption. 
The idea that the universe is "expanding" really means that the amount of space in the universe is increasing. This doesn't mean it literally has to "come" from outside the universe. We only really define space as a property of within the universe. What if space and energy were linked, and energy were being converted into space? Then we wouldn't need the universe to be expanding into something else. Not that I think necessarily that is true, just an example. 

I'm not too up to date with modern theories, but I believe the initial idea behind multiple universes was to do with quantum decoherence, think that's what it's called. A particle completely separate/not interacting with any other system has a possibility to be in any state, position/momentum etc, but when it's "measured" i.e. it interacts with anything, then it has to assume some fairly definite properties. The state of the particle before it interacts is represented by a waveform. When it is measured, this waveform kind of has to "collapse" into one particular state. One interpretation is that we see only one "branch" of the wavefunction, but the whole waveform still exists, we just can't interact with it. Hence, lots of coinciding wavefunction systems overlapped on one another forming discrete systems that are completely separated to each other, or in other words other universes.


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## bigtex1989 (Feb 7, 2011)

dizzycactus said:


> That seems to be a slightly flawed assumption.
> The idea that the universe is "expanding" really means that the amount of space in the universe is increasing. This doesn't mean it literally has to "come" from outside the universe. We only really define space as a property of within the universe. What if space and energy were linked, and energy were being converted into space? Then we wouldn't need the universe to be expanding into something else. Not that I think necessarily that is true, just an example.


Exactly, which is why that is only one possibility XD. There are countless others, that one is just the most simple to me which is why I decided to go with it in lieu of more complicated ones.



dizzycactus said:


> I'm not too up to date with modern theories, but I believe the initial idea behind multiple universes was to do with quantum decoherence, think that's what it's called. A particle completely separate/not interacting with any other system has a possibility to be in any state, position/momentum etc, but when it's "measured" i.e. it interacts with anything, then it has to assume some fairly definite properties. The state of the particle before it interacts is represented by a waveform. When it is measured, this waveform kind of has to "collapse" into one particular state. One interpretation is that we see only one "branch" of the wavefunction, but the whole waveform still exists, we just can't interact with it. Hence, lots of coinciding wavefunction systems overlapped on one another forming discrete systems that are completely separated to each other, or in other words other universes.


Multiverse "theories" have been around for several thousand years actually, which is kind of weird to think about. There are several references to multiple dimensions and multiple universes in various Talmud passages as well as Kabbalah literature dating back thousands of years. While not developed, there was definitely a sense of it. I personally have never heard of quantum decoherence to justify a multiverse. Learn something new everyday I guess XD


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## Death Persuades (Feb 17, 2012)

They don't hypothesize, they theorize. Hypotheses require concrete testing, whereas theorizing can be based merely on logical thought. I'm not sure if I'm correct, but the theory of multiple universes is based on the string theory, which suggests that everything that exists is based on strings that resonate and vibrate at varying frequencies, and they think that lower and higher frequencies could be other universes or "dimensions". Another theory suggests that the Universe is only one "bubble" amidst billions of other "bubbles", but we cannot reach those... I may be wrong, but I think this is how the theories go.


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## Wulfyn (May 22, 2010)

josue0098 said:


> They don't hypothesize, they theorize. Hypotheses require concrete testing, whereas theorizing can be based merely on logical thought.


You got these the wrong way around.


There are 2 basic ideas for a multiverse, one based on intuition (which is more begging the question than pure logic) and another based on scientific reasoning.

The intuitive argument is that if the universe was created from natural causes (yet to be proven of course) then why would this be the only universe? If there is something a priori to this universe that can cause a universe then why not others? The reason why it is begging the question is because there is nothing to say that there is a reason why or a reason why not, we know that little about it.

The scientific argument (well the strongest one) is based on string theory, which allows for multiple dimenstions, and is called M theory. Put simply the greater number of dimensions that fall out of the mathematics of strong theory (which varies depending on which type of strong theory you are going for) allows for other lower order universes to be created from them. It's a bit ontological to extend one world to many worlds to all possible worlds, but there is reason behind it that extends it beyond just begging the question.



Even if there is a multiverse without the ability to move from one to the other the concept is pretty meaningless. For example if universes existed as separate non-touching entities then it really wouldn't matter if there was one of billions because it would never interact with us, and therefore technically not be real. However it would be real if there was some sort of interaction. There are throughts that gravity can cross to other universes and that universes have a membrace that touches other universes. Although highly theoretical it is thought that this picture might be evidence for it:


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## sofort99 (Mar 27, 2010)

It falls out in quantum theory math. It's *way* beyond the scope on a forum discussion, but you should be able to google it.

You can also start here:

Many-worlds interpretation - Wikipedia, the free encyclopedia


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## TranceMan (Aug 26, 2012)

sofort99 said:


> It falls out in quantum theory math. It's *way* beyond the scope on a forum discussion, but you should be able to google it.
> 
> You can also start here:
> 
> Many-worlds interpretation - Wikipedia, the free encyclopedia


I was just browsing this thread hoping to see some raging debate, and now I'm 50/50 that I'm going to be up all night researching this or possibly die from a stroke.

(I hope someone gets the joke)


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## sofort99 (Mar 27, 2010)

TranceMan said:


> I was just browsing this thread hoping to see some raging debate, and now I'm 50/50 that I'm going to be up all night or possibly die from a stroke.
> 
> (I hope someone gets the joke)


What ever you do, don't get in a box.


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## wuliheron (Sep 5, 2011)

In modern physics the idea of parallel universes first got a boost when it was shown it could be used to explain quantum Indeterminacy in a very natural and straightforward manner. Many believed it was preferable to other possible explanations such as stochastic models, panpsychism, and hidden variables if for no other reason then because it proposed a simple explanation that could be tested. However, after over half a century of tests there still is no strong supporting evidence. String theory, for example, has been around for 40 years and other than some very interesting mathematics hasn't produced a single useful thing.

My own view is that what has occurred over the last century is similar to what happened in the nineteenth century with the aether theories. Physicists were stuck in this philosophical rut of trying to explain everything from a reductionist point of view and couldn't think outside the box. The evidence kept piling up that they were on the wrong track, but it was the only track they knew so their theories got wilder each year until Einstein came along and showed them how it could be done differently. 

Instead of trying to use a reductionist approach he used a more holistic one. Since the advent of quantum mechanics and relativity every branch of the sciences has adopted their own more holistic theories not because of any philosophical beliefs, but because by definition holistic theories describe more than reduction theories. The tradeoff is that reductionist theories are easier to create and work with, while holistic ones can be a royal pain due to their broad foundations. That's life and the entire history of physics where scientists have had to repeatedly wait for the mathematics and technology to be developed first in order to make the next big leap. In the mean time, they do what they can with what they've got no matter how silly it might sound at times.


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## Raain (Jan 3, 2012)

Thanks for the responses!!

Why does the discovery of the Higgs Boson mean that it's more likely that other universes exist?


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## Wulfyn (May 22, 2010)

wuliheron said:


> That's life and the entire history of physics where scientists have had to repeatedly wait for the mathematics and technology to be developed first in order to make the next big leap.


This is why I think that experimental physicists are often highly under-rated. Rutherford was firing streams of helium nuclei at a thin sheet of gold in 1909. His observations and model of the atom was then refined by Bohr and Schrodinger, two far more famous scientists - but it all began with that experiment. In 1909. Amazing.


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## wuliheron (Sep 5, 2011)

Wulfyn said:


> This is why I think that experimental physicists are often highly under-rated. Rutherford was firing streams of helium nuclei at a thin sheet of gold in 1909. His observations and model of the atom was then refined by Bohr and Schrodinger, two far more famous scientists - but it all began with that experiment. In 1909. Amazing.


Michael Faraday was simply amazing and way ahead of his time. On Star Trek Spock once commented that he was, "... endeavoring to construct a pneumonic memory circuit using stone knives and bear skins." That's the kind of minor miracles Faraday managed routinely in his lab despite little formal education. Theorists might get all the fame and glory, but that's true in any profession. There are always those who get more credit than they deserve and those who get less than they deserve.


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## wuliheron (Sep 5, 2011)

Raain said:


> Thanks for the responses!!
> 
> Why does the discovery of the Higgs Boson mean that it's more likely that other universes exist?


It only suggests it might be more possible because the mass of the particle turns out to vaguely support supersymmetry theory. The hint is so vague that to even confirm supersymmetry, much less parallel worlds, they'll have to do more experiments studying cosmic rays which are so energetic you'd need a particle accelerator the size of the solar system to reproduce them.


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## Lawless Land (Jul 10, 2012)

I have a simple way of answering this question: Theres more than one universe because...theres more than one universe


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## sofort99 (Mar 27, 2010)

Raain said:


> Thanks for the responses!!
> 
> Why does the discovery of the Higgs Boson mean that it's more likely that other universes exist?


I'd like to point out the higgs boson hasn't been discovered, despite media reports to the contrary.

The actual announcement was that on some channels, they now have data that would be consistent with confirming it, and on other channels they have now data that would be consistent with disproving it, so the grand sum is we now have data we'd like to look at.


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## sofort99 (Mar 27, 2010)

Raain said:


> I started a thread were I asked how it would be possible to still believe in God if the Omniverse was never created.
> 
> http://personalitycafe.com/critical...-god-if-universe-eternal-never-created-7.html
> 
> ...


First you have to define "parallel Universe".

We live in a bubble with a radius of 42 billion light years. That is because that's as far as we can see, because it's as far as light could travel since the big bang. It's called the Hubble bubble. Because the universe is expanding, the edge of the bubble is receding faster than the speed of light, so we can never see farther.

If 82 billion light years away, there is a guy looking towards us in his own bubble, and we are looking towards him, we will never see each other.

f you look at the volume of the bubble, you get the Hubble volume. there are only so many ways you could rearrange all the matter you could put in a Hubble volume. So in an infinite universe, eventually they are going to have to start repeating.

The math says you can't go farther than 10^10^118 meters until you have to bump into one.

So right now, there are an infinite number of *us*, having the exact same discussion just in *this* universe, making a Hubble bubble, for all intents and purposes a universe in itself, and out own universe a de facto multiverse, without us even having to go to the trouble of really *having* other universes in the way you normally think of it.

And this is just a type I parallel universe. 

The Tegmark Classifications are:

Level 1: Regions Beyond Cosmic Horizon - The universe is essentially infinitely big and contains matter at roughly the same distribution as we see it throughout the universe. Matter can combine in only so many different configurations. Given an infinite amount of space, it stands to reason there exists another portion of the universe in which an exact duplicate of our world - and, in fact, our entire visible universe - exists.

Level 2: Other Post-Inflation Bubbles - Separate universes spring up as bubbles of spacetime undergoing its own form of expansion, under the rules dictated by inflation theory. The laws of physics in these universes could be very different from our own.

Level 3: The Many Worlds of Quantum Physics - According to this approach to quantum physics, events unfold in every single possible way, just in different universes. Science fiction "alternate history" stories utilize this sort of a parallel universe model, so it's the most well known outside of physics.

Level 4: Other Mathematical Structures - This type of parallel universes is sort of a catch-all for other mathematical structures which we can conceive of, but which we don't observe as physical realities in our universe. The Level 4 parallel universes are ones which are governed by different equations from those that govern our universe. Unlike Level 2 universes, it's not just different manifestations of the same fundamental rules, but entirely different sets of rules.

There is also Greene's Classifications, but they tend to just subdivide Tegmark's, in my opinion.

Edited to add: Good lord. I need to get some sleep. Just ignore anything i write that has numbers in it for now.

When we look at the edge of the Hubble bubble, we are looking back 13.5 billion years in time, but we can actually see ~42 billion light years away because of expansion.


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## Entropic (Jun 15, 2012)

josue0098 said:


> They don't hypothesize, they theorize. Hypotheses require concrete testing, whereas theorizing can be based merely on logical thought. I'm not sure if I'm correct, but the theory of multiple universes is based on the string theory, which suggests that everything that exists is based on strings that resonate and vibrate at varying frequencies, and they think that lower and higher frequencies could be other universes or "dimensions". Another theory suggests that the Universe is only one "bubble" amidst billions of other "bubbles", but we cannot reach those... I may be wrong, but I think this is how the theories go.


Nope, it's the other way around. A hypothesis is an underlying assumption of how the world operates based on current observations. In order to test the hypothesis, we need to conduct a scientific study that gathers data to see if the hypothesis remains true or not. Based on these results, we can then postitulate a scientific theory of how the world actually operates. In such a sense, the hypothesis is simply a point of departure of how to formulate a scientific theory. 

I think you confuse the word theory with how it's used in common language here. Easy mistake to make, I should add. I think it's more fair to say that the current scientific theories we have regarding the multiverses are formed based on the current scientific data we possess. Do note that expansion of current scientific theories can be done by postitulating more hypotheses as well.


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## Wulfyn (May 22, 2010)

sofort99 said:


> f you look at the volume of the bubble, you get the Hubble volume. there are only so many ways you could rearrange all the matter you could put in a Hubble volume. So in an infinite universe, eventually they are going to have to start repeating.


Wouldn't that also require infinite matter? If space is infinite but matter is not then couldn't there be an infinite number of empty volumes and no repeating volume that has matter in it?


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## Sat (May 30, 2012)

That theory exists, simply for the sake of covering all possible outcomes of what the universe(s) is like beyond what we can observe by looking at the Cosmic Microwave Background Radiation signature, which represents the light-speed bubble we exist in. The quantum Many Worlds Interpretation, while mathematically sound, seems wasteful to me, because of its assumption that EVERY possible outcome for every particle in the universe has happened, albeit in another universe. This infinite splitting of the universe creates such a plethora of universes that the concept of infinity pales in comparison. While it may well be true, if it is, then each moment of tangible reality is to be cherished, and there is no meaning to life, for I exist simply because of some statistical fluctuation which made it possible for me to, at this moment, and there is no guarantee that I will in the next moment.

Another theory suggests every black hole in our universe is connected to a white hole in either our universe or in a parallel universe, where the matter going in the black hole comes out spewing from a white hole.

There are theories of multiple universes existing congruently to our own, but in alternate, exotic dimensions.

Regardless of which theory or theories one subscribes to, most of the current mathematics suggests that it is impossible to communicate between these alternate (parallel) universes, and so the area remains mostly outside the spotlight of cutting edge research. I hope no mathematicians are around when I say that..=p

The discovery of the Higgs Boson will suggest that the last 40 years of theoretical research hasn't been in vain, and that we are on the right track with regard to The Standard Model of particle physics. There have been discrepancies in the mass of the Higgs thought to be found which suggest our current theoretical model needs revision, but is not totally incorrect, had we found a particle outside the range of masses as predicted by the model. Its going to be an interesting next 50 years.


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