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I haven't heard anything about that. The theories state that antimatter also froze out of energy as the universe cooled. It annihilated ordinary matter and the energy of that annihilation is now the COMB. There was a slight imbalance between matter and anti-matter -- one part in a billion -- and it is that extra excess of matter that forms the matter in the universe.
Oh, but I thought the net energy is zero. How could there be an imbalance and no net energy?
But it's insufficient data that matters. Even when the equations of M-theory are solved, that doesn't mean they reflect reality until we can test them.
Except you are assuming that the equations of M-theory can be solved. And there is no concensus that this is even possible.
Originally Posted by lucaspa
This isn't about formulations of the BB. This is about what caused the BB.
Again, this isn't the issue. We are not concerned with the cause of the expansion of the universe, but why there is a universe at all. Expanding or not.
If I may be so bold...there is a slight contradiction here. "this is about what caused the BB" and "We are not concerned with the cause of the expansion of the universe"
In non-singular formulations, the BB and the expansion of the universe are one and the same. For example, #4 and #5 (in your previous post) deal with the cause of the expansion, and do not answer questions about the existence of the universe. String theory (or M theory) indicate the cause of expansion of dimensional space (#4, #5), but not the origins of that space. The first three, however do refer to existence.
Originally Posted by lucaspa
"Even if there is only one possible unified theory, it is just a set of rules and equations. What is it that breathes fire into the equations and makes a universe for them to describe? The usual approach of science of constructing a mathematical model cannot answer the questions of why there should be a universe for the model to describe. Why does the universe go to all the bother of existing? " Stephen Hawking, A Brief History of Time, pg 174.
Even with quantum gravity, the question remains unanswered. Quantum gravity will unify physics so we don't have two major but separate theories to describe the universe: relativity and QM. But it won't tell us the cause of the BB.
I'm picking nits (and repeating myself...sorry). But the link between existence itself and the cause of the BB is only realized if the universe began as a singularity....so it does depend on the formulation of the BB.
Hawking is pondering the *existence* of the universe itself, not the cause of the BB in this text....and there is a difference. Quantum gravity will certainly help us to unravel more of the mystery of the cause of the BB, but it will not help us answer the question of why the universe *exists* in the first place. For example, if M-theory is right then we may very well link some particular sequence of 'p-brane events' to dimensional expansion. This will give us insights into the cause of the BB. But the origins of dimensional space, if any, will remain enigmatic.
On the other hand, perhaps its an endless puzzle, with each discovery simply uncovering more puzzle....and quantum gravity is simply another piece.
Except you are assuming that the equations of M-theory can be solved. And there is no concensus that this is even possible.
I hadn't heard that the equations can't be solved. Could you document that? What I have read is that either 1) the theory doesn't match some part of the existing universe or 2) that the theory doesn't predict any new knowledge that could be used to test it.
If the equations can't be solved, work will be done either 1) on new ways to solve them or 2) revising M-theory so that it has equations that can be solved. That's how science works. Having a bunch of unsolvable equations around that you can't then test are simply no good. It's an intolerable situation.
If I may be so bold...there is a slight contradiction here. "this is about what caused the BB" and "We are not concerned with the cause of the expansion of the universe"
In non-singular formulations, the BB and the expansion of the universe are one and the same. For example, #4 and #5 (in your previous post) deal with the cause of the expansion, and do not answer questions about the existence of the universe.
I beg to differ. Inflation is concerned with the expansion. #4 is quantum fluctuation and gives you a universe that is an uncaused quantum event. In our universe matter pops into existence out of the "nothing" of the vacuum all the time. However, this takes place in an existing spacetime. As I have read about it, what M theory brings to the table is having spacetime itself be a quantum fluctuation. So now matter/energy and spacetime are uncaused quantum fluctuations. No creator.
#5 is also about causing the universe. It is a rival to the BB in that you don't have a point source for the universe, but rather a "Big Splat". Now, in one sense ekpyrotic pushes back the question of First Cause because you can now ask: where did those two 11 D branes come from? But if I am reading the articles about ekpyrotic right, they arise by quantum fluctuation.
__________________ "If sound science appears to contradict the Bible, we may be sure that it is our interpretation of the Bible that is at fault." Christian Observer, 1832, pg. 437
"Christians should look on evolution simply as the method by which God works." Rev. James McCosh, theologian and President of Princeton, 1890
Oh, but I thought the net energy is zero. How could there be an imbalance and no net energy?
Because the negative energy of gravity and matter/energy is balanced by the positive energy of the expansion. Therefore no net energy. The imbalance between matter and antimatter is within the matter/energy part of the equation. Remember, when matter and anti-matter meet, the result is energy.
So, when the universe cooled, the energy in the early universe froze out to matter. A very nearly equal amounts of matter and antimatter. They met and annhilated and gave rise to energy -- the Cosmic Microwave Background Radiation. There was slightly -- 1 particle per billion -- more matter than antimatter.
__________________ "If sound science appears to contradict the Bible, we may be sure that it is our interpretation of the Bible that is at fault." Christian Observer, 1832, pg. 437
"Christians should look on evolution simply as the method by which God works." Rev. James McCosh, theologian and President of Princeton, 1890
I beg to differ. Inflation is concerned with the expansion. #4 is quantum fluctuation and gives you a universe that is an uncaused quantum event. In our universe matter pops into existence out of the "nothing" of the vacuum all the time. However, this takes place in an existing spacetime. As I have read about it, what M theory brings to the table is having spacetime itself be a quantum fluctuation. So now matter/energy and spacetime are uncaused quantum fluctuations. No creator.
But doesn't that entail that there is a negative form of spacetime? If it is a fluctuation, correct me if I'm wrong, then it has an opposite.
I haven't heard anything about that. The theories state that antimatter also froze out of energy as the universe cooled. It annihilated ordinary matter and the energy of that annihilation is now the COMB. There was a slight imbalance between matter and anti-matter -- one part in a billion -- and it is that extra excess of matter that forms the matter in the universe.
Really? I might need to brush up on my cosmology. I think this description needs to be expanded a little. (but I have to review my sources).
The background radiation is a result of two things:
1. The hot, dense state of the early universe: Antimatter particles and matter particles would have both been produced early in the big bang, but the majority of the particles present at this time were *already photons*. In other words, any annihilations would have produced additional photons in the hot plasma of the early universe, but the majority of the CMB photons would have *already existed*. So the CMB is not exacltly due to matter/antimatter annihilations, but rather it is mostly due to the formation of photons in the early stages of the BB. I could be wrong, let me know if you understand it differently
2. Expansion: When the universe expands, it cools. For the photons, this expansion would affect them by stretching out their wavelegths, giving us the relatively 'cool' CMB photon density we have today. I'm sure we agree on this point anyway.
I hadn't heard that the equations can't be solved. Could you document that? What I have read is that either 1) the theory doesn't match some part of the existing universe or 2) that the theory doesn't predict any new knowledge that could be used to test it.
If the equations can't be solved, work will be done either 1) on new ways to solve them or 2) revising M-theory so that it has equations that can be solved. That's how science works. Having a bunch of unsolvable equations around that you can't then test are simply no good. It's an intolerable situation.
I have to sift through my books. Right now M-theory consists of solving partial equations with partial data. We still have an infinite range of possible shapes for the 7 curled up dimensions for example....and several give physics that might be compatible with our universe. No-one knows if the space is uniform, or if it can change from one region of space to another. Everyone is working with the idea that we will one day solve some of these puzzles. But it is not uncommon to hear physicists mumbling that some of these questions may not be answerable.
If we find, for example, that supersymmetry is *not true*...then M-theory will be relagated to the dust bin, and its equations may not have a solution simply because they do not describe the real universe in any way.
But evidence is mounting...and it's looking hopeful.
So I suppose I agree with you...it is about the data really.
Originally Posted by lucaspa
#5 is also about causing the universe. It is a rival to the BB in that you don't have a point source for the universe, but rather a "Big Splat". Now, in one sense ekpyrotic pushes back the question of First Cause because you can now ask: where did those two 11 D branes come from? But if I am reading the articles about ekpyrotic right, they arise by quantum fluctuation.
The branes are extended strings...and they may have appeared as a QM fluctuation. The dimensional space that those branes inhabit could not have arisen from a quantum fluctuation. How can you get a quantum fluctuation when you have no quantum field?
Just to clarify something: this is from one of your posts:
Originally Posted by lucspa
Even with quantum gravity, the question remains unanswered. Quantum gravity will unify physics so we don't have two major but separate theories to describe the universe: relativity and QM. But it won't tell us the cause of the BB.
And this is from another:
Originally Posted by lucaspa
#5 is also about causing the universe. It is a rival to the BB in that you don't have a point source for the universe, but rather a "Big Splat". Now, in one sense ekpyrotic pushes back the question of First Cause because you can now ask: where did those two 11 D branes come from? But if I am reading the articles about ekpyrotic right, they arise by quantum fluctuation.
The point I was trying to make is this: ekpyrotic (derived from M-theory) formulates the first cause of the BB in part *because it includes quantum gravity*. So QM gravity is essential to the M-theory formulation on the cause of the BB. There are other theories on the table (involving multiple expanding universes, etc) that also include a variation of quantum gravity. Quantum gravity is indeed tied in to the cause of the BB in this context (esp #4, and #5, as I said).
Of course, Hawking is pondering the greater question of existence. For example both #4 and #5 have the universe starting out as a planck size nugget...a quantum field that can give rise to fluctuations. But the origin of that quantum field remains enigmatic under all current formulations.
Just to clarify something: this is from one of your posts:
And this is from another:
The point I was trying to make is this: ekpyrotic (derived from M-theory) formulates the first cause of the BB in part *because it includes quantum gravity*.
That's not how I read it. M-theory still doesn't have quantum gravity. It "simply" states that particles aren't really particles but are small strings. Ekpyrotic explored the possibility of getting a universe from a collision of 2 branes. It was an attempt to falsify that idea, but it turned out that you can get the universe that way -- assuming, of course, that there are branes to begin with.
Of course, Hawking is pondering the greater question of existence. For example both #4 and #5 have the universe starting out as a planck size nugget...a quantum field that can give rise to fluctuations. But the origin of that quantum field remains enigmatic under all current formulations.
1. The Planck sized nugget is the flucutation, not the cause of it.
2. And the origin of the quantum field is uncaused. It has no origin in the conventional sense.
__________________ "If sound science appears to contradict the Bible, we may be sure that it is our interpretation of the Bible that is at fault." Christian Observer, 1832, pg. 437
"Christians should look on evolution simply as the method by which God works." Rev. James McCosh, theologian and President of Princeton, 1890
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