What exactly is gravity? It's created by an object's mass & is a force of attraction but what exactly is it?

Answer 1

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 (see this Question of the Day), 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:

Answer 2

There are all kinds of theories but, it seems that even the greatest scientists can only hypothesise.
The space station has people working in the environment of space which causes weightlessness caused by their tendency to continue in a straight line but, due to the force of Gravity, they are continuously falling back to earth, the curvature of which is falling away at the same rate so, they stay in orbit.
An artificial gravity is produced to enable their work to be performed by rotating the station at a controlled speed.
Rotation causes centrifugal force which is controlled by the opposite centripetal force which produces the circular motion.
(As when a mass (object), on the end of a string is rotated).
From this, I make the Hypothesis that Gravity is based on this opposition of forces.
The Earth and EVERYTHING on it, including the atmosphere, is rotating.
Everything also has mass and is rotating and therefore held to the Earth by Centripetal force called Gravity.
As everyone is making more or less 'wild' guesses, then this is my 'wild' guess.
Will we ever really know ??

(However, the 'Thumbs down' merchant knows the true definition of Gravity so, everyone else, we'd better forget it !)

Answer 3

Gravity is a force with which two bodies with a certain Mass and at a certain distance attract. Don't be fooled and think only the Earth attracts us! U attract it as well, but because of the significantly smaller mass you have it's quite inconspicuous to see.
U should also know that gravity is probably the weakest attraction force. It's billions and billions of times weaker than the electrical forces

Answer 4

according to newtonion classical physics, gravity is a "force" that interacts between objects, however einstein never liked the thought of action at a distance, so according to general relativity, gravity is not some mysterious force acting through space, but is the warping of space itself.

Answer 5

It is the force of attraction which the earth exerts on a body's mass

Answer 6

Its simply an attraction force between two masses.

Answer 7

I'll answer this in two ways ...

1) you probably need to understand a bit about what science (and physics in particular) offers us by way of explanations.

Theories about things like gravity are usually presented in popular media (and even at school) as telling us what the thing is.

In fact, physical theories, by and large, tell us what things do - and not what they *are*.

The best theories explain everything we know already about a phenomenon, correct a few errors in the old theory and make dramatic and unexpected predictions that are confirmed later by experiment.


The theory is usually formulated in mathematical terms - this gives a description of what will happen in a given situation. If you are looking for a 'what is it' then this is about the best thing you'll have!

Popular (or even professional) scientific interpretation of what the 'thing' is will tend some kind of metaphor based on the similarity between the mathematics of the theory and the mathematics of some familiar phenomenon.

Einsteins theory of gravity - general relativity - is a very good example of all this, which leads nicely to

(2) gravity - what does general relativity tell us about it

OK - having said that physical theories do not tell us what the things 'are', I'll do my best to bend that rule.

Einsteins mathematical framework for describing general relativity is very often interpreted as being similar to the familiar phenomenon of ... ball-bearings on a flexible sheet of material.

So - the ball bearings are masses, the flexible sheet is space (or space-time if your being exact) and the distortion caused by the ball-bearing bending the sheet down is 'gravity' (see image on wiki page).

To prove to yourself that a distorted sheet acts like gravity - imagine trying to roll a much lighter ball-bearing in a straight line across the sheet. It would curve in toward the ball-bearing due to the deformed shape of the sheet.

So - the picture we interpreted from the mathematical formulation allows us to understand at a very general level what gravity is. But gravity is *not* the picture.

In truth, we still don't know what it is. But Einsteins theory of general relativity still (nearly 100 years on) makes perfect predictions for every situation in which it can be tested.

Answer 8

Gravity is always attractive, and it can act over large distances. It is an invisible force that is all-pervading. No one really understands exactly why, but gravity is a force that pulls objects toward each other. The mass of the objects and distance between the objects affects the strength of the force of gravity. Greater masses attract with more force, and the force weakens as the objects get further apart.

Gravity is one of the four fundamental forces of nature, along with the electromagnetic force and the strong and weak nuclear forces. Gravity is the weakest of all the fundamental interactions. Gravity acts between particles of matter. (It an also act between quantities of energy!) More technically, it has an infinite range through space, and weakens as the inverse-square of the distance between bodies. All theoretical and observational studies are completely consistent witht the idea that it travels no faster than the speed of light—and no slower. Many physicists are firmly convinced that gravity is a cousin to the other forces in Nature that we know about, including electromagnetism. The exact, mathematical, way to show this unity is called Supersting Theory.

Gravity's first mathematical description as a "universal" force was by Sir Isaac Newton. Newton's description remained unchanged until Albert Einsten published his General Theory of Relativity. Newton described it as a force acting at a distance, and Einstein described it as an artifact of mass and energy that curve space-time. Einstein described gravity as a deformation in space, caused by the presence of massive objects, similar to the way a heavy ball would warp a sheet of rubber. This deformation 'told' smaller things how to move through space, so they either went into orbit or fell onto the larger celestial object. Einstein would have argued that gravity is just objects following the shortest path possible through space-time (a space-time geodesic). Einsteins theory of relativity predicted that objects with great mass deform speace around them, causing light to deflect into them. That has been shown to be true. He also predicted that gravity could travel in gravity waves, which we haven't seen yet.

Gravitational waves are somewhat analogous to the waves of electromagnetic energy that we call light. Light waves are created by electric charges in motion; similarly, gravitational waves are created by masses in motion. Gravity waves are easiest to conceptualize when they are regarded in a similar sense as electromagnetic waves: they carry information about a change in a gravitational field with time.

Although Einsten's idea is necessary for describing the evolution of the universe as a whole, Netwon's theory works well enough when gravitational forces are not extremely strong.

Perhaps the most unusal thing about gravity we know about is that, unlike the other forces of nature, gravity is intimately related to space and time. In fact, sapce and time are viewed by physicists, and the mathematics of relatively theory, as qualities of gravitational field of the cosmos that have no independent existence. Gravity does not exist like the frosting on a cake, embedded in some larger arena of space and time. Instead, the "frosting" is everything, and matter is embedded and imtimately and indivisibly connected to it. If you could turn off gravity, it is mathematically predicted that space and time would also vanish!

Theoreticians believe it is at its heart a 'quantum field' just like the fields associated with the other fundamental forces. it would then be a simmering cloud of gravitons-which come and go according to the dictates of Heisenberg's Uncertainty Principle. The graviton particles carry a 'spin' of 2 units, have no rest mass, and travel as packets of space-time curvature, at the speed of light. Some physicists believe that these gravitions take the form of one-dimensional closed 'strings' of energy-that wiggle in an 11-dimensional arena. Another idea has gravitons as donut-shaped loops that interconnect like some enormous chain mail suit.

None of this explains why mass or distance affects gravity, though. To do that we must look at the theories of scientists more recent than Einstein. According to theory, the reason mass is proportional to gravity is because everything with mass emits tiny particles called gravitons. These gravitons are responsible for gravitational attraction. The more mass, the more gravitons. Graviton theory also accounts for differences in gravitational attraction over distances. Most gravitons exist in a cloud around the object. As distance from the object increases, the density of the graviton cloud goes down, so there is less gravitational attraction.

Answer 9

The force with which earth attracts the body towards its center is called GRAVITY
IF THE OBJECT HAS GREATER MASS IT HAS GREATER ABILITY TO ATTRACT THE OTHER BODIES.AS THE MASS OF BODIES AROUND US IS VERY LESS THEREFORE THEY CAN NOT ATTRACT THE OTHER BODIES WITH GREATER FORCE BUT THE MASS OF EARTH IS VERY LARGE THEREFORE IT ATTRACTS THE OTHER BODIES WITH GREATER FORCE.

Answer 10

Thats what Einstein wanted to know;among other things he pointed out you could get the same effect from going up or down in a lift(elevator for my usa fans).So your not to expect any sudden understanding,Be brave its a bummer.