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How does gravity affect anything?

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posted on Aug, 4 2004 @ 09:37 PM
I found this interesting.

how does gravity affect ANYTHING, no one really knows the medium at which gravity is transfered so therefore how can we correctly depict HOW anything is affected by gravity...

althogh you can answer the question "what are the effects of gravity on light and sound?" which would be answered by, a ray of light is acted upon by a gravitational force, this is only noticed around very massive objects such as dense decaying stars and blackholes where two images of the same star can be seen because two rays of light are bent toward your eye. Sound on the other hand is just wave changes in air pressure, air pressure in the atmosphere does depend on the gravitational force of the earth in order to exist, but changes in this pressure is merely just the interaction between many air molecules. So no sound is not affected by air unless you take into account the speed of sound increasing as the density of the air increased which would increase slightly the higher pressure of air you had in a certain volume of space which would depend on the gravitational force from the body of mass which is enclosed by these particles of gas. (I think the subject in the preceeding paragraph is interesting b/c i have never thought of a stronger acceleration due to gravity on the surface of a planet increasing the speed of sound on that planet, someone please comment on this, i would love to hear more.)

but with that aside the answer to how gravity affects these is ultimately unknown. Newton said that the gravitational force existed between any two bodies of mass, but the fact that electromagnetic waves (composed of MASSLESS photons) are affected by gravity crushes this theory. Einstein's General Relativity on an elementry level states that the presence of matter bends the fabric of space causing massive objects and rays of electromagnetic waves to diolate their perception of "straight" on this coordinate system thus bending the path at which they follow in relation to our flat perception of straight. This theory works with common day understanding but it still does not explain the HOW. The theory of the undiscovered graviton has come about in recent years.. recent as in a few decades ago. Think about it this way, if intensity of electromagnetic waves is proportional to the inverse square of the spherical radius away from the center point and electromagnetic waves are made up of massless packets of energy (photons) then this is also a perfect model for a MUCH weaker and far harder to detect graviton which also follows the identical inverse square law but with a far less constant of proportionality.

So HOW gravity works, is not really known, but the effects of gravity on different things has been stated.

Anyone have any ideas about it?
I'll post my ideas later, I want to see what other people come up with.

posted on Aug, 4 2004 @ 11:05 PM
think of the universe as a sheet of rubber (2D), scaled down a dimension from 3D for conceptual purposes. Most EM waves ripple parallel to this sheet, gravity on the other hand is a force that pulls the rubber sheet in the 3rd dimension (4th in reality), perpindicular to the 2D plane. Assume the universe/rubber-sheet has a natual tension to it. Put two mass/objects on it. Could it be that the function of minimum tension on the overall rubber sheet is where two separate objects are next to each other? Could it be that the effects of gravity (beyond the basic space deformation) is simply a minimum tension function that causes mass objects to come together. Like a rubber band retracts to it's closest to relaxed state.

Gravity is a natural space tension effect of a pull in the 4th dimension of the Universe?
This ofcourse does not say why gravity pulls in the 4th dimension.

(Im not sure about this) If you take a sheet of rubber held in a circular frame and place several marbles around on it. Then jiggle it around. Won't the marbles tend to come together in the center?

will attempt this experiment and get back to you.

posted on Aug, 5 2004 @ 01:14 AM
Light will travel a geodesic in the presence of a gravitational field. This is very simple to understand. Einsteins principle of equivalence states that no experiment can differentiate a non-inertial reference frame and a gravitaitonal field and thus all effects are equivalent. Hence place yourself in an accelerating elevator and shine a flashlight. The flashlight will appear to travel a curved path. The same effect is observed in the presence of a gravitational field. Hence when you think gravity think non-inertial reference frame(accelerating reference frame), and it will make problems a lot simpler.

posted on Aug, 5 2004 @ 01:14 AM
Each particle of matter attracts every other particle with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

Gravity is actually quite a weak force in the universe. The energy of electromagnetism is Billions of times stronger. The electromagnetic field of your body and the ground your standing on is enough to over power all the Gravity of the earth which is trying to pull you to its core.

Speed of gravity: Einstein's theory of relativity predicts that the speed of gravity (defined as the speed at which changes in location of a mass are propagated to other masses) should be consistent with the speed of light. In 2002, the Fomalont-Kopeikin experiment produced measurements of the speed of gravity which matched this prediction. However, this experiment has not yet been widely peer-reviewed, and is facing criticism from those who claim that Fomalont-Kopeikin did nothing more than measure the speed of light in a convoluted manner.

The question of why atoms attract one another is still not understood. The goal is to combine gravity, electromagnetism and strong and weak nuclear forces into a single unified theory. Until we get a unified theory Gravity will remain a enigma

posted on Aug, 5 2004 @ 03:29 AM
I think, according to einstein's relativity theory, thats gravity is caused by the both earth rotation on its own axis and around the sun. I don't believe electromagnetism have something to do with it, instead of protecting us from meteors and other spaces moving objects, with the Hallen belt.

posted on Aug, 17 2004 @ 12:54 PM
The source of gravity is the stress-energy tensor T. The tensor T has 4*4 = 16 components T_ab:

T_00 T_01 T_02 T_03
T_10 T_11 T_12 T_13
T_20 T_21 T_22 T_23
T_30 T_31 T_32 T_33

I'm going to quote Misner, Thorpe and Wheeler's gravitation about the meaning of these components. They work bottom-up, starting with the simplest component and generalizing until they explain the entire tensor.

T_00 = density of mass-energy
T_a0 = density of a-component of momentum
T_0b = b-component of energy flux
T_Ab = a, b component of "stress" = b-component of flux of a-component of momentum = a-component of force produced by fields and matter at x^b-e acting on fields and matter x^a+e across a unit surface, the perpendicular to which is e_b, the unit vector in the b direction.

Mass-energy is there, momentum is there, energy-flux and some other stuff. All this affects the curvature of spacetime. Everything simply moves on the straighest possible lines through curved spacetime, called geodesics.

Newtonian gravity approximates this, but doesn't add energy, momentum and energy flux into the equation.

Nans' idea is wrong, although momentum has to be added in the equation.

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