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Bogie
2007-Oct-24, 06:23 PM
I can’t help rejecting creation out of nothing (ex nihilo), and I’m pretty sure I’m in good company in the scientific community.

BBT features GRT and the Cosmological Principle (CP). I have no problem with a universe that is homogeneous and isotropic on a large scale, so I don’t think the CP part of BBT enters into the question about origin.

Realizing that GTR breaks down in the Planck Regime when it is tracked backward towards its limit, one must conclude that if there is going to be a cosmology that actually addresses a scenario that doesn’t require an “ex nihilo” beginning to our expanding universe, it will have two characteristics.

It will include a theory of gravity that works in both the Planck Regime and at the atomic particle level.

It will predict a fundamental unifying particle that unifies gravity with the Standard Model of Fundamental Particles.

Does it follow that such a particle itself would be the cause of gravity, or would explain the physics of gravity in terms of force instead of curved space-time?

Michael Noonan
2007-Oct-25, 01:43 PM
Basically you are also looking for a unifying theory. With the advent of general relativity and quantum theory shortly after that they ideas have been a most formidable barrier to such ideas.

In 1905 there was work on a 5D structure for steady state and later 4D for Twistor, quantum is 6D microstructures and I wont say what I have played with in dimensions just that it is not cones and Twistor.

In a way one could ask the question is it even worth looking for unified theory and that is said in the kindest way possible. If understood it is quite likely that unified theory is simply a starting point for beginning to question what we are ourselves.

We might not be ready for that.

Bogie
2007-Oct-25, 02:46 PM
Basically you are also looking for a unifying theory...
Science, I, and I bet you too would like a unified theory. The question in the OP was asked because I hope that someone who is knowledgeable on the OP subject would merely tell me if my conclusion is correct and if not just give me twenty or thirty words that might elevate my thinking closer to reality.

Am I on the right track as far as my thinking goes in the OP?





Beyond that, your concerns, “Is it even worth looking for unified theory?” and “We might not be ready for that.” have some validity. I say some validity anyway, less validity than it had in 1905 and through the twentieth century, and IMHO, less and less validity all of the time. But that is a subject for a thread on the state of “world today” and the “future of the world”.

I would be happy on this thread if someone would address my question so I would know if I have boiled it down correctly.

Fortunate
2007-Oct-25, 05:30 PM
Bogie,

I am no "expert", but I think what we need most is some observational evidence of one or more cases in which GR breaks down on the level of the very small. I think that the next few breakthroughs will come from the experimental side. From the empirical basis provided by experimental results, we can begin to develop a new theory, or it may turn out that an already existing theory seems favored.

The theory or theories that emerge at that point may naturally suggest a unification in terms of a single primordial force, or may suggest a fundamental dichotomy between gravity and the other three.

01101001
2007-Oct-25, 06:03 PM
Does it follow that such a particle itself would be the cause of gravity, or would explain the physics of gravity in terms of force instead of curved space-time?

Does it follow that a hypothetically predicted particle, a part of a hypothetically conjectured cosmology (that you seem to just declare one must conclude), would be a cause of gravity?

I don't know. It's your collection of hypotheticals. You tell us. (But, could you tell us outside of Q&A, since it seems to be so iffy.)

Bogie
2007-Oct-25, 06:24 PM
Bogie,

I am no "expert", but I think what we need most is some observational evidence of one or more cases in which GR breaks down on the level of the very small. I think that the next few breakthroughs will come from the experimental side. From the empirical basis provided by experimental results, we can begin to develop a new theory, or it may turn out that an already existing theory seems favored.

The theory or theories that emerge at that point may naturally suggest a unification in terms of a single primordial force, or may suggest a fundamental dichotomy between gravity and the other three.Thanks Fortunate.

I guess we have to be satisfied with that. You put it very well.

Bogie
2007-Oct-25, 06:31 PM
Does it follow that a hypothetically predicted particle, a part of a hypothetically conjectured cosmology (that you seem to just declare one must conclude), would be a cause of gravity?

I don't know. It's your collection of hypotheticals. You tell us. (But, could you tell us outside of Q&A, since it seems to be so iffy.)
Attitude is everything.

Not yours specifically, but the attitude that people take as they approach a problem like in the OP. I think Fortunate understood my attitude and the attitude of the scientific community and gave a perfectly sufficient answer.

I don't think you added anything necessary and so let's let it stand with Fortunate's contribution.

01101001
2007-Oct-25, 06:38 PM
Attitude is everything.

Good attitude! Great. Problem solved.

Nereid
2007-Oct-25, 07:01 PM
I can’t help rejecting creation out of nothing (ex nihilo), and I’m pretty sure I’m in good company in the scientific community.
The history of science is replete with well-meaning, intelligent folk who rejected something that later turned out to be consistent with a great many very good observations.

Think of the Earth being not flat, the Earth not moving, the Earth not being the centre of the universe, material things having to be either a wave or a particle, no upper limit to the speed with which things can go, relative space and time, no 'vital force', Einstein's (and Rosen's, and ...) rejection of some key aspects of quantum theory, ...

Cue the J.B.S. Haldane quote ....

BBT features GRT and the Cosmological Principle (CP). I have no problem with a universe that is homogeneous and isotropic on a large scale, so I don’t think the CP part of BBT enters into the question about origin.

Realizing that GTR breaks down in the Planck Regime when it is tracked backward towards its limit,
Another thing that a sober look at the history of science, especially physics, will bring home to you is the importance of pedantry, nitpicking, etc.

In this case, one nit to pick is that GR doesn't break down in the Planck regime, but only at any singularities ... what 'breaks down' is that GR and the Standard Model's mutual incompatibility become intolerable (crudely, solve the equations for a state in the Planck regime with GR and then with the SM, and you get completely inconsistent results).

Note too that the mutual incompatibility is well below anything currently measurable, in the observable universe, so there is, today, no observation or experiment you could do to get a handle on how the universe actually addresses that incompatibility.

one must conclude that if there is going to be a cosmology that actually addresses a scenario that doesn’t require an “ex nihilo” beginning to our expanding universe, it will have two characteristics.

It will include a theory of gravity that works in both the Planck Regime and at the atomic particle level.

It will predict a fundamental unifying particle that unifies gravity with the Standard Model of Fundamental Particles.
Cue Haldane again ...

These kinds of conclusions presuppose, or assume, certain regularities about how the universe works ... brave is the person who thinks they can dictate how the universe should work, based on little more than internal beliefs concerning rationality ...

Does it follow that such a particle itself would be the cause of gravity, or would explain the physics of gravity in terms of force instead of curved space-time?
Sadly, nothing like this 'follows' at all ...

It may turn out that gravity is like turtles, geometry all the way down (i.e. not a 'force' in any sense like the strong, weak, and electromagnetic).

It may turn out that the other three forces aren't, that they too are also geometry.

Or it may turn out that the universe is queerer than anything anyone has yet imagined ...

Bogie
2007-Oct-25, 07:12 PM
The history of science is replete with well-meaning, intelligent folk who rejected something that later turned out to be consistent with a great many very good observations.

Think of the Earth being not flat, the Earth not moving, the Earth not being the centre of the universe, material things having to be either a wave or a particle, no upper limit to the speed with which things can go, relative space and time, no 'vital force', Einstein's (and Rosen's, and ...) rejection of some key aspects of quantum theory, ...

Cue the J.B.S. Haldane quote ....

Another thing that a sober look at the history of science, especially physics, will bring home to you is the importance of pedantry, nitpicking, etc.

In this case, one nit to pick is that GR doesn't break down in the Planck regime, but only at any singularities ... what 'breaks down' is that GR and the Standard Model's mutual incompatibility become intolerable (crudely, solve the equations for a state in the Planck regime with GR and then with the SM, and you get completely inconsistent results).

Note too that the mutual incompatibility is well below anything currently measurable, in the observable universe, so there is, today, no observation or experiment you could do to get a handle on how the universe actually addresses that incompatibility.

Cue Haldane again ...

These kinds of conclusions presuppose, or assume, certain regularities about how the universe works ... brave is the person who thinks they can dictate how the universe should work, based on little more than internal beliefs concerning rationality ...

Sadly, nothing like this 'follows' at all ...

It may turn out that gravity is like turtles, geometry all the way down (i.e. not a 'force' in any sense like the strong, weak, and electromagnetic).

It may turn out that the other three forces aren't, that they too are also geometry.

Or it may turn out that the universe is queerer than anything anyone has yet imagined ...
Thanks Nereid, for taking the time to help my thinking. I feel well adjusted.