can anyone explain scientifically how gravity works?

Question

how it keeps us stable and all of that good stuff.

or is it one of those "who knows how it works, it just works" type of explanations

Answer 1

Newton was the first person to study gravity seriously, and he came up with the law of universal gravitation:

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.

The standard formula for gravity is:

Gravitational force = (G * m1 * m2) / (d2)

where G is the gravitational constant, m1 and m2 are the masses of the two objects for which you are calculating the force, and d is the distance between the centers of gravity of the two masses.

G has the value of 6.67 x 10E-8 dyne * cm2/gm2. That means that if you put two 1-gram objects 1 centimeter apart from one another, they will attract each other with the force of 6.67 x 10E-8 dyne. A dyne is equal to about 0.001 gram weight, meaning that if you have a dyne of force available, it can lift 0.001 grams in Earth's gravitational field. So 6.67 x 10E-8 dyne is a miniscule force. When you deal with massive bodies like the Earth, however, which has a mass of 6E+24 kilograms, it adds up to a rather powerful force. It is also interesting to think about the fact that every atom attracts every other atom in the universe in some small way!

Einstein later came along and redefined gravity, so there are now two models -- Newtonian and Einsteinian. Einsteinian gravitational theory has features that allow it to predict the motion of light around very massive objects and several other interesting phenomena. According to Encyclopedia Britannica:

The general theory of relativity addresses the problem of gravity and that of nonuniform, or accelerated, motion. In one of his famous thought-experiments, Einstein showed that it is not possible to distinguish between an inertial frame of reference in a gravitational field and an accelerated frame of reference. That is, an observer in a closed space capsule who found himself pressing down on his seat could not tell whether he and the capsule were at rest in a gravitational field, or whether he and the capsule were undergoing acceleration. From this principle of equivalence, Einstein moved to a geometric interpretation of gravitation. The presence of mass or concentrated energy causes a local curvature in the space-time continuum. This curvature is such that the inertial paths of bodies are no longer straight lines but some form of curved (orbital) path, and this acceleration is what is called gravitation.

If certain assumptions and simplifications are made, Einstein's equations handle Newtonian gravity as a subset.

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.

Answer 2

I think the problem there is with the word "works." A lot of us think of gravity as being a mechanism or a force that is generated by some source in the same way an electric field is generated by a battery or generator.

But it isn't really that way. Gravity is a property of space and time in the same way that color is a property of paint or bark is a property of doggie.

The "rubber sheet" analogy is a good starting place, but not very satisfying if you are trying to build a power unit for an interstellar battleship. It leaves practical questions unanswered, like, "how does each billiard ball know the angle at which the rubber sheet's asymptote impinges on it, and how does the rubber sheet know how seriously to deform itself for each size and shape of ball?"

It's kind of like "how does the water know the boat is coming?"

So in a large sense, understanding gravity will require a kind of thinking we have not yet invented. But it's worth thinking about, in between listening to each other's stomachs gurgling on nice Sunday afternoons.

Answer 3

LOL .. there is a long list of credible scientists that refute the Big Bang "Theory" .... but of course .... you are too intelligent to take that into consideration .... since your mind is made up .... The whole notion tha the Big Bang theory proposes some 15 billion years ago, the universe was created by the burst of a "singularity," this burst subsequently giving rise to the entirety of existent matter .. has many unanswered questions .. just on the basis of "singularity" ... but you choose to ignore this .. scientifically minded somehow .... Not withstanding the confusion between the Euclidean mathematical model of a point and the fact that no such points exist in reality, as well as series of common misuses of the term "infinity" lead to some serious questions in regards to the "scientific method". If existence itself was created by the burst of this singularity, as you apparently believe .... then, did or did not the singularity itself, whatever it was, exist, too? If you answer that it did exist, it could not have created the universe, or all of existence. If you answer that it did not exist, then it also could not have created anything, because to create, it is necessary to first have that which creates, i.e., some entity that exists. Now, evolution ... I am amazed on how many people believe that there is hard scientific proof ... I can go along with the theory ... although flawed .. it is a theory .... but to portend that you have all thew answers ... as if you understand what happened is scientifically arrogant and irresponsible ..... Do we know what happened ....??? Of course we do not ....

Answer 4

Imagine a flat sheet of rubber with a bowling ball sitting on it. Where the bowling rests, the sheet is distorted. Drop a marble anywhere on the slope of the distortion and it will move towards the bowling ball. Now substitute space for the rubber sheet, the bowling ball for mass, and the distortion for gravity. In other words, mass changes the geometry of space. Exactly *how* this occurs isn't at all understood, but that it's true has been proven over and over by countless experiments.

Answer 5

The modern explanation of Gravity is given by the General Theory of Relativity. Space and time are a single entity called SpaceTime. Bodies possessing mass deform this entity like balls placed on a rubber sheet. The curvatures produced induce motion due to inertia of the masses.

Gravity is 'felt' at a distance due to the exchange of gravitons. These particles, predicted by the Standard Model (not yet observed) travel faster than light.

Answer 6

General Relativity describes it as a distortion of space-time created by the prescense of mass. It is also equivalent with the accelerative force.

Try looking for a good physics books, like "Relativity: The Special and the General Theory" by A. Einstein himself. Good book.

Answer 7

newton's law of gravitation states that two point masses with exert an attractive force on each other of the magnitude that is proportional to the product of their masses and inversely propoertional to the square of the distance between them.

F= G m1m2/r^2

the earth, being a huge sphere with high density of mass in its core, exerts gravitational pull on other masses. the earth sucks you and I, though we suck it just as much, because the pull is mutual. however, because the earth is much more massive (heavy) than we are, we appear to be moved by the earth. ie we fall to the ground, the earth doesnt fall up to us. the moon and other heavenly bodies also experience gravitational pull, though this pull is used as a centripetal force which causes orbiting (another story for another time)

don't get confused with relativity until you actually understand in depth the classical model.

Answer 8

think of gravity like a really good glue that keeps you glued to the surface of the planet you are living in. just its a sm,art kind of glue. its like the new flip flops that scientists have made that have no straps on it. it has a kind of glue on it to keep the feet attached but the glue is a kind that dosent sticks to the skin and easily lets your feet out of it. same kind of a thing is gravity.

Answer 9

gravity cannot be explained as of yet

try the M theory instead of relativity.
still searching though.

3 hours long but fun. shows list up to down not left to right
http://www.pbs.org/wgbh/nova/elegant/program.html

Answer 10

Have you tried looking it up?

http://en.wikipedia.org/wiki/Gravity