What is gravity?

[sjastro]

Originally Posted by Nesti

...I feel that we still don't have an answer to the question, "What is Gravity?" (causally), we haven't as yet discussed a reason why it exists either...I raise that question with trepidation.

I can suggest a cause...a reason...but I don't think that anyone will like it.

Cheers
Mark

"What is gravity" is actually a philosophical or metaphysical question.
Science struggles with "what is" questions. "How" questions are easier to answer.

A person of religious disposition would argue that God created gravity, a philosopher might answer that gravity is part of our consciousness.

Steven

[PCH (Paul)]

Ditto. This thread is currently beyond many peoples' comprehension at the moment IMHO. (Don't flay me alive if I'm wrong !)

It's certainly beyond me anyway

[sjastro]

Originally Posted by Bassnut

Yes please . I havent got a clue what you guys are on about in the last few posts, so maybe in a way an average dummy can understand ? .

We could be conning you guys and talking complete BS.

Steven

[Bassnut (Fred)]

I once saw an impressive arguement that the "reason" for life, is simply a device to increase entropy. Given entropy is a fundamental universal "pressure", could the reason for the existance of gravity just be as another entropy increasing device?

[multiweb (Marc)]

Way too technical for me this thread... I was always told gravity is what happens to you when you pass the 40 year old barrier?...

[Bassnut (Fred)]

Originally Posted by sjastro

"What is gravity" is actually a philosophical or metaphysical question.
Science struggles with "what is" questions. "How" questions are easier to answer.

A person of religious disposition would argue that God created gravity, a philosopher might answer that gravity is part of our consciousness.

Steven

Your right, I dont like it.

(come on Mark, you have a go)

[Nesti (Mark)]

Originally Posted by sjastro

The number of components is based on the rank of the curvature tensor. For example the Riemann curvature tensor which has a rank of 4 has 4^4=256 components for 4 dimensional space.
The Ricci tensor which is a contracted version of the Riemann tensor has 2^4=16 components in 4 dimensional space. Taking into account symmetry the total number of components is 10.

Thus GR is a gravitational theory for 10 potentials (Newtonian theory has only 1 potential).

The Christoffel symbols in the Ricci or Einstein field equations result in the partial differentiation (1st and second order) of the each metric component. The metric component is the potential.

If the metric components are constant, the Christoffel symbols vanish and the metric is simply a geodesic or straight line in flat space.
Non vanishing Christoffel symbols (metric components are not constant) indicates curved geodesics.

Regards

Steven

Yes, I agree here.

[Nesti (Mark)]

Originally Posted by sjastro

"What is gravity" is actually a philosophical or metaphysical question.
Science struggles with "what is" questions. "How" questions are easier to answer.

A person of religious disposition would argue that God created gravity, a philosopher might answer that gravity is part of our consciousness.

Steven

Yes, agree here also.
Quote:
... the more you see how strangely Nature behaves, the harder it is to make a model that explains how even the simplest phenomena actually work. So theoretical physics has given up on that.
Richard Feynman


I have a philosophical disposition when it come to SR & GR and quantum measurement for that matter, therefore a collective mentality (with suggestions). It's a very long story, currently in manuscript form if you're interested Steven...it will conflict with your beliefs, as sole math/science descriptions conflict with mine, but it does tie-in much of quantum measurement, time symmetry (lack of symmetry perhaps) and it does tackle a cause for SR & GR head-on. I pull no punches near the end.

[Nesti (Mark)]

Originally Posted by Bassnut

Your right, I dont like it.

(come on Mark, you have a go)

An extract from about 3/4 through;

In geometry, curvature may be defined as the mathematical obstruction within a curvilinear coordinate system, so that it cannot be transformed into a flat coordinate system. In the general theory of relativity, gravitation may be defined as the obstruction of tidal forces within a gravitational field, so that it cannot be transformed into a field of flat spacetime. Therefore, might our own destiny, as well as all others’, be defined as the obstruction of freedom of choice within a causal particle universe (the observer influence), so that it cannot be transformed into a purely deterministic reality? If true, then instigating these features, facilitating the diversity of all realities, is the central node. Astonishingly, it may well underpin the structure of mathematics itself.
Author

[Nesti (Mark)]

Originally Posted by multiweb

Way too technical for me this thread... I was always told gravity is what happens to you when you pass the 40 year old barrier?...

Bugger, just turned 40...B-a-s-t-a-r-d-o!

[multiweb (Marc)]

Originally Posted by Nesti

An extract from about 3/4 through;

In geometry, curvature may be defined as the mathematical obstruction within a curvilinear coordinate system, so that it cannot be transformed into a flat coordinate system. In the general theory of relativity, gravitation may be defined as the obstruction of tidal forces within a gravitational field, so that it cannot be transformed into a field of flat spacetime. Therefore, might our own destiny, as well as all others’, be defined as the obstruction of freedom of choice within a causal particle universe (the observer influence), so that it cannot be transformed into a purely deterministic reality? If true, then instigating these features, facilitating the diversity of all realities, is the central node. Astonishingly, it may well underpin the structure of mathematics itself.
Author

Mate, I thought you were just a dude holding a yellow plane but now you're scaring the s**t out of me

[Bassnut (Fred)]

Ive read that about 30 times, carefully, and I think I actually get it, sort of, nice quote.

[Nesti (Mark)]

Originally Posted by Bassnut

Yes please . I havent got a clue what you guys are on about in the last few posts, so maybe in a way an average dummy can understand ? .

Steven is discussing the factual boundaries of GR as we currently understand it, and I can see his angle. I am trying to introduce other aspects which I feel needs to be addressed. It pertains to a reason for gravitation.

It's kind of like Newton's clockwork universe, where god created the universe, would it up, and set it in motion. Deterministic processes carry the evolution from there-on-in. BUT, freedom of choice (free will), consciousness and thought, have not been accounted for in such a system. Even Newton realised these things, and thought it may one day lead to athiesm.

For me, everything, every effect must be attributed to a cause, there is no independent self fulfilling system; everything must pertain to a common purpose or central reality.
All phenomena link together in a mutually conditioning network
Buddha, 500BC

The notion of a self fulfilling prophecy (General Relativity) makes no sense, it must have a purpose and a cause.

There is no mind absolute or free will, but the mind is determined for willing this or that by a cause which is determined in its turn by another cause, and this one again, by another, and so on to infinity.
Benedictus de Spinoza, 1673

[sjastro]

Originally Posted by Nesti

I have a philosophical disposition when it come to SR & GR and quantum measurement for that matter, therefore a collective mentality (with suggestions). It's a very long story, currently in manuscript form if you're interested Steven...it will conflict with your beliefs, as sole math/science descriptions conflict with mine, but it does tie-in much of quantum measurement, time symmetry (lack of symmetry perhaps) and it does tackle a cause for SR & GR head-on. I pull no punches near the end.

Yes I would like to read the article.

Regards

Steven

[Nesti (Mark)]

Originally Posted by sjastro

Yes I would like to read the article.

Regards

Steven

It's not an article, it's a book that's taken 23 years to put together. Due to be published Dec 2009.

Bomb me an email address and I'll flick it across (8Mb).

Mark

[Bassnut (Fred)]

Mark. So you think cause and effect can be extended to quantum uncertainty. Its not uncertain, its just we havent havent developed enough to understand it?, or are we fundamentaly designed, intentially, not to be able to, ever, in which case we could never prove either way?

[xelasnave]

Back on topic..what is gravity

seriously however this is such a great thread and although I grasp little and understrand less just trying to keep up to speed googling each new term that comes in has been wonderful...I thank the distraction this thread has given me on what I call a bad day (personally that is)...

And sorry for being a grump earlier.
alex

[xelasnave]

How are the tragectories of our space craft calculated? What math is used Is Newtonian sufficient or do they use GR?
alex

[xelasnave]

and if not gr why not?
alex

[shane.mcneil]

Originally Posted by multiweb

Way too technical for me this thread... I was always told gravity is what happens to you when you pass the 40 year old barrier?...

Yeah it's also known as furniture disease. It's when your chest drops into your drawers.

Shane