A question about gravity.

This is not the textbook answer, but this is what I personally think is going on...

General Relativity tells us that when objects are in free fall thier motion cannot be detected without external reference. This means that the gravitational field around an object in free fall must be symetrical, otherwise directionality would be implied (this part is from the textbook).

When two objects are held apart from each other the gravitational fields (spacial distortion) interact and are stretched toward each other just like two hands pressed down on a pillow near each other (textbook again).

When objects are in free fall, the asymetrical distortion of the gravitational fields around them are cancelled out by the acceleration of the objects toward each other and the system is in equilibrium (textbook again).

The "force" which causes one thing to fall toward another is the result of space trying to reach equilibrium by seeking a symetrical state (not textbook; my personal conclusion)

The same thing causes Inertia (and again; my personal conclusion here)

When you drop your pencil, an approximate answer is that it falls because it is in the gravitational field of the Earth and experiences a force towards the center of the Earth. A technically more complete answer is that both objects are in each others' fields so the Earth also moves infinitessimally toward the pencil. People who study particle theory believe that any two objects which exert a force on each other do so by exchanging particles that mediate that particular field - the graviton for gravity. The people who think in terms of geometric theories like GR, look at it a different way,

The real honest answer is "we don't really know ... yet". The search for a unified explanation of gravity that explains the phenomina that we measure both on a big scale, and on the scale of particles is one of the major efforts in Physics right now.

There is quite a bit we do know, and our knowledge keeps expanding.

Under General Relativity, gravity is not considered a force. One of the basic assumptions of General Relativity is that there is no way (with any experiment or instruments) to tell if you are accelerating, or being "pulled" by gravity. Rosborne alluded to this. This was a starting point for Einstein and General Relativity is based on this.

Unfortunately these questions are highly mathematical. It takes a few years and a pretty deep understanding of math to understand the work being done by physicists. Many of the descriptions in the press make me wince since they oversimplify and make people have the wrong impressions.

For example, very few people understand what it means that "space is curved". Many people make assumptions based on their experience curved real-life things, that go against the math behind "curved" space.

For a pretty good laymans explanation that doesn't oversimplify the math yet gives a pretty complete picture of the current state of physics-- I highly recommend the book.....
Three Roads to Quantum Gravity by Lee Smolin

He gives a good of the current attempts to solve the problem including string theory.

the most fundamental answers to "why" do not have answers

even if a grand unified theory is put together and some explanation of why gravity and magnetism and all the other forces become explained...then we still wouldn't know why that unified theory existed

and if you think about it, there has got to be some basic level of things that just IS and doesn't have any reason

it's similar to the origin of energy...where did it come from? you can keep tracing things back, but if you go back far enough, you had to start with something that just "was"

There is no such thing as gravity. The earth sucks.

Lemme dust off this old whore . . .


Gravity isn't just a good idea . . . it's the law.

"The Elegant Universe" is also a good book for string theory.

It goes into WHY we haven't been able to detect the graviton, what they think it is and how theorists believe it interacts in the physical world. It isn't complete by any stretch of the imagination, but it is the first step at defining gravity through a unification theory.

Re: A question about gravity.


They're starting to:

http://users.bestweb.net/~sansbury/book03.pdf

http://www.aquestionoftime.com/index.htm

The basic reality seems to be that gravity is an electrostatic effect of some sort and not a basic force of nature at all.

gungas, since you have introduced these new topics perhaps you could summarize these links?

in the first link, i found a large section regarding celestial attraction due to electric dipoles and planetary torque...this would be separate from gravity

in the second link, there was an example relating the force of gravity to the force of someone pulling a cart in order to try to disprove general relativity...this also does not explain gravity

perahps I was not finding the specific parts you intended us to find

anyway, electrostatic fields attract or repel depending on charge, but gravity attracts even when the electrostatic field repels!

Near as I can tell, the one author, Sansbury, is claiming that individual electrons can act as electrostatic dipoles and that the aggregate effect of this can create other kinds of forces including gravity.

There is one thing about the theory which is seriously interesting in that he offers a rational explanation for the instantaneous propagation of gravity which does not violate causality as relativity does, and which at the same time offers an explanation for the Michelson/Morley experiment which does not require deformable time.

The other book basically notes that the theory which lives by the "thought experiment" can die by it. Relativity was based on thought experiments, and not real evidence.

my 2 cents
Gravity is an intriguing construct. It is an area that GR and QED have a problem reconciling. Some base it on an imaginary particle called the graviton. Others feel it may unlock the key to unifying the other three basic forces of nature. It has its own constants that help us use it to come up with more advanced formulas and constructs.

To me I think that it is an electromagnetic attraction that exists between all matter. Matter being made up of protons and electrons that are charged but not canceling each other out when it comes to attraction. Similar to how two magnets of opposite charges attract each other I see all matter not just gravitons being the carriers of gravitational attraction. The negative energy in mass A attracting the positive energy in mass B and vice versa.

Since I see all matter not just gravitons as being carriers that can magnify the aggregate effects of gravity it is my proposition that the density of the atmosphere around our planet specifically correlates to gravitational attraction. Would those of you who are well versed in physics agree with me or disagree with me that the density of our atmosphere would affect the strength of gravitational attraction?

Along these lines does anyone happen to have any data on the amount of energy that would be required to maintain an orbit of a satellite at 50km from sea level verses the amount of energy required to maintain an orbit of a satellite at 5000km from sea level? I think there is something in these two formulas that would back up my proposition that the density of atmosphere around our planet increases the gravitational attraction thus causing the need for much more energy to be exhausted to maintain an orbit of 50km then it would be to maintain an orbit of 5000km.

Am I off base or missing something?