Multiverse Theory

[ramses]

So I saw this today,

http://www.financialexpress.com/news/groundbreaking-theory-suggests-a-multiverse/1132732?utm_source=twitterfeed&utm_medium=twitter

Interesting.

[7499275]

I have believed in the multiverse theory for a good time now ( although my friends think I'm an idiot for it ) but from my understanding that article linked above states that in our universe physics may change depending on the location? This is rather interesting plus strange. I had always imagined that once we got to the "End" of our universe a worm hole would open up allowing a ship or probe or what ever it is to pass through into another universe and it would be a visible change where we would KNOW we left our universe.

This poses an interesting theory that what if its seamless and physics could change in a part of the universe from the other and we would think it to be our universe when in actuality we changed into another without realizing it.

I hope I didn't confuse anyone...

[Brotoro]

I don't think that article is saying that the values of fundamental physical constants are different from place to place in our universe... Only that they could be different form 'place to place' in a multiverse, with each of the places they refer to being a different universe.

[7499275]

I don't think that article is saying that the values of fundamental physical constants are different from place to place in our universe... Only that they could be different form 'place to place' in a multiverse, with each of the places they refer to being a different universe.

That's what I said near the bottom, we could enter a multiverse without realizing it and think its the same universe we call home when it is a different universe and there fore the physics are different.

[Themohawkninja]

This poses an interesting theory that what if its seamless and physics could change in a part of the universe from the other and we would think it to be our universe when in actuality we changed into another without realizing it.

Well, it is theorized that the four forces were once one superforce, and that the cooling of the universe split them apart, so I wonder if different cooling times could create different physics in different universes. Analogous to how you can get many different types of stone simply by how quickly lava cools.

[ramses]

I've always thought of it as simply multiple "Big Bangs" happening at different times and locations.One "Big Bang" equals one Universe.

Physics probably wouldn't be constant throughout, but have slight variations from one to the next.

[K^2]

Well, it is theorized that the four forces were once one superforce, and that the cooling of the universe split them apart, so I wonder if different cooling times could create different physics in different universes. Analogous to how you can get many different types of stone simply by how quickly lava cools.

No, it doesn't work that way. The way the forces split depends only on temperature and density of matter. How the matter expanded and cooled doesn't make a difference.

Besides, the constants of which the multiverse hypothesis talks are a bit more fundamental than that. These are, among other things, the very parameters that determine when certain forces will become relevant.

There is absolutely zero evidence for this hypothesis, however. It's a convenient one, because it is an ad-hoc explanation for any set of conditions in the surrounding universe that seem to be just right for the existence of human kind, but it is difficult to falsify for that very reason, and as such, will probably remain untested.

[[ Jeremy ]]

I base M-Theory around the Schrodinger principle: There are multiple states, but you are only allowed to interact with only one. This means there could be an infinitesmal number of universes, all of them slightly different from each other, and all the universes are created when an event could have more than one outcome, like in Schrodinger's cat.

[Themohawkninja]

I base M-Theory around the Schrodinger principle: There are multiple states, but you are only allowed to interact with only one. This means there could be an infinitesmal number of universes, all of them slightly different from each other, and all the universes are created when an event could have more than one outcome, like in Schrodinger's cat.

I thought that the Schordinger principle was more along the lines of: "There CAN be multiple states, but only one is true, therefore all of the possibilities must be simultaneously viewed upon as true until further evidence is given".

[Brotoro]

I base M-Theory around the Schrodinger principle: There are multiple states, but you are only allowed to interact with only one. This means there could be an infinitesmal number of universes, all of them slightly different from each other, and all the universes are created when an event could have more than one outcome, like in Schrodinger's cat.

Ah, but what happens if a quantum mechanical interaction can result in three different possible outcomes with probabilities of 50%, 25%, and 25%? Do one half, one quarter, and one quarter new universes get created? Or 50, 25, and 25 of them?

[K^2]

I base M-Theory around the Schrodinger principle: There are multiple states, but you are only allowed to interact with only one. This means there could be an infinitesmal number of universes, all of them slightly different from each other, and all the universes are created when an event could have more than one outcome, like in Schrodinger's cat.

You are confusing multiverse and Many Worlds. Many Worlds does, indeed, have something to do with our interaction with the observable universe and the Schrodinger Cat. Though, it's a bit more complicated than that. You don't really "create" new worlds at quantum events, but for simplicity, looking at it as time-line splitting up isn't all together wrong. Also, M-Theory is something completely different.

Ah, but what happens if a quantum mechanical interaction can result in three different possible outcomes with probabilities of 50%, 25%, and 25%? Do one half, one quarter, and one quarter new universes get created? Or 50, 25, and 25 of them?

Neither. Think of it more like intensities. A beam of light can be 50% red, 25% green, and 25% blue. It's really all just the same beam of light, but you can decompose it into components of different intensities. The reason it gets interpreted as probabilities has more to do with stat mech than pure quantum physics.

Edited June 24, 2013 by K^2

[rasheed]

Imagine a Universe within a Black hole that is within another universe that is within a blackhole.

This 500x

This gets werid

[Brabbit1987]

http://www.dailymail.co.uk/sciencetech/article-2326869/Is-universe-merely-billions-Evidence-existence-multiverse-revealed-time-cosmic-map.html

I have always believed in the multi-verse hypothesis. The version I believe is there are an infinite amount of universes. Imagine a blank piece of paper. Then draw 20 circles on it with different sizes. Each circle represents a universe each with it's own rules of physics. All the space in between the universes allows another universe to be able to pop into existence. Each universe grows but never actually collides with another because the space in between grows as well. There are only a certain amount of possible outcomes for the rules physics could have, so I believe there would be more universes with the same physics as ours. They would be nearly identical with very slight differences.

Traveling to another universe in this hypothesis would be impossible. You could never travel in the space between universes as no rules of physics exist. Connecting 2 universe with different physics would probably cause physics to go nuts in both universes. Black holes and worm holes are out of the question, and besides they only bend time and space with in a universe, not outside of it. This is actually why many scientists do not like this hypothesis. A multi-verse hypothesis can't easily be proven, nor can you just simply go to one to prove it.

Well that is the basic idea of the version I believe in.

Course the only reason I believe it is because it sounds pretty reasonable actually when you think about it. We have always wondered how our universe just happened to have the correct physics for it to harbor life. The chances are so small. However, if there is a multi-verse, it would no longer be rare as we once thought. Actually it could very well be common. It would actually explain a lot of things in our current model of physics.

Edited June 24, 2013 by Brabbit1987

[WestAir]

We have always wondered how our universe just happened to have the correct physics for it to harbor life. The chances are so small. However, if there is a multi-verse, it would no longer be rare as we once thought. Actually it could very well be common. It would actually explain a lot of things in our current model of physics.

I always wondered about that line of thought. Everyone says how "rare" and "impressive" it is Earth can sustain and create life. "If just one variable were different life wouldn't happen."; I often hear how we're just the right distance from the sun, etc etc -- and now you're saying the same thing about our Universe: That the laws of physics are just right for it to allow life to exist. That any miniscule change to those physics would render it impossible for us to exist.

I have a retort to that thought.

Pretend that when the Big Bang happened, the laws of physics turned out differently. Let's pretend that the weak force turned out stronger than the strong force, and that electromagnetism never propagated at C. With this change, the molecular bonds that allow life to exist would be impossible to construct, and life would never happen. No one would be around to know that life never started. Therefor, I suggest our existence isn't nearly as spectacular as we assume. The prerequisite to knowing we exist is existing itself; how can that be miraculous? The Universe has had life-bearing potential for > 10,000,000,000 years.

Even if it is miraculous, it certainly can't be considered impossibly rare. Not when, given the size of just the observable Universe alone, there are likely Billions of life-bearing planets out there. I just can't accept the idea that the circumstances leading to our existence is rare, let alone surprising.

[K^2]

Of course. But this sort of logic only applies if there are many universes. If it is so, then however unlikely life is, if there are enough universes out there, it will happen in some of them, and we are guaranteed to be in one of these.

But if there is just one, then it bearing life only by chance is still very unlikely. You can't rely on statistics to fix that.

As far as things being just right for life, consider the blocks of atomic matter. Despite up quarks being slightly heavier than the down quarks, and despite the fact that separating two charges takes energy, it turns out that the neutron is just slightly heavier than a hydrogen atom. A lone neutron left to itself will decay into a proton and an electron. This is why the most common element in the universe is hydrogen. Now, imagine that, as common sense would dictate, hydrogen was heavier. Every atom of hydrogen in this universe would decay to neutrons. There would be no clouds of hydrogen plasma to make stars. Just clouds of neutron matter. No such thing as chemistry in all of existence. Not even the most remote opportunity for life.

Fortunately, isospin asymmetry played in our favor and allowed this multitude of elements to exist. But this requires quite a few parameters being just right. Do they have to be this way? Who knows. But it's hardly so by chance. Either there were many "attempts," or there is a much deeper reason for all of this.