How does gravity work?

Question

Gravitational force = (G * m1 * m2) / (d2) but why is that? Why/how are masses attracted to each other?

Answer 1

The law of gravitational force is constant.

Answer 2

Newton's theory of universal gravity does not attempt to explain the nature of the gravitational force beyond describing it as an instantaneous force acting between masses that varies with the square of the distance of separation between them. To describe how gravity 'works' it is necessary to turn to Einstein's theory.

Einstein's theory of General Relativity (1915) is a cause and effect theory. The theory describes the fabric of space-time as a medium that may be distorted by the presence of mass and energy. From his earlier relativity theory, Einstein had related mass and energy in the famous equation: -

E = mc²

From this concept, he described the curvature or distortion of space-time as due to the total sum of mass-energy present within the region of distorted space. It is the curvature of space-time we call gravity. Thus, our planet follows the 'straightest' path or path of least action whilst it orbits the mutually curved space around the Sun. An object falling to earth, under the pull of gravity, is following the curvature of space in the region around the surface of the Earth. Einstein described the relationship between space-time curvature and the mass-energy causing it, in the tensor field equation: -

G = 8πT

Where 'G' is the Einstein tensor representing the 'gravity' or curvature of space-time and 'T' is the total energy tensor representing the mass-energy creating the gravitational curvature of the space-time.

The theory, accurately predicts many features of the solar system, such as the peculiar motion of Mercury’s perihelion, and may be used to account for the gravitational physics of black holes and neutron stars. The extreme high pressure physics at the core of a star may be described using this theory. General relativity also predicted the Big Bang origin of the universe, although Einstein refused to accept the conclusion. He later claimed that this erroneous conclusion was his biggest blunder. Overall, after ninety-three years, General Relativity is still the best theory of gravity that we have!

Answer 3

My friend, never pick finger on what Nature does and sets. Whatever nature does, is always perfect.

The inverse square law is a fundamental law in nature and nature has set it for our welfare. NOONE knows why is that.

Answer 4

It's a law of nature.  I love it.  I teach science, and when ever a student or I drop something, I always curse: "gravity."  It is so cool though.  The heavier something is the more gravity it has on other objects.  I hear there is an asteriod in the belt between Mars and Earth or is it Mars and Jupiter that has is 6 miles long.  It is widely believed tha if you landed on it (in a space suit) you could walk on it, but if you tripped, you's be gone.

Answer 5

In Newtonian physics, it is an inherent property of matter that masses attract each other. In Einsteinian physics, Mass deforms space so that other masses fall in that direction. Regardless of the mechanism postulated, gravity is, just like magnetism is or the weak atomic force is. Science explains mechanisms, not ultimate causes.

Answer 6

"Why?"

The philosophy department is down the hall.

Answer 7

lol.  You seek the Holy Grail.

How masses are attracted to each other you know.

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

Why they are is THE question of modern physics. There is a suspicion that gravitational force is somehow linked to electro-magnatism.  i.e. the Unified Field Theory.  IF someone can come up with a functional UFT then we will theoretically be able to use electrical energy to generate anti gravity.

I personally feel Einstein's deformed space theory is a bit silly & on the wrong side of Occam's razor to boot.  So I'll leave it's description to the believers.

If you are Interested in an honest to god UFT,  I have one,  But it's highly speculative & won't help you in your physics class.

Email me if you're interested,

Have fun,.

Answer 8

(Energy = Mass) + Spacetime = Gravity

Energy + Spacetime = Gravity

Mass + Spacetime = Gravity

Spacetime + Mass:

http://www.ligo-wa.caltech.edu/LIGO_Publ...

Gravity.

Its like putting a heavy ball in the middle of a suspended sheet then putting little balls on the edge all the little balls will fall down the curve in the sheet and surround the big ball. The big ball represents mass and the sheet represents spacetime.

But unlike the sheet spacetime is 4D meaning it has Length, Height, Width & Motion so a ball in the middle of space time will pull things all around it smaller in mass towards it hence gravity.

Even you a person had a tennis ball and was out in the middle of space  the ball will be attracted to you as you will create gravity to it pulling it towards you.