# Einstein vs Newton on Gravity!

## Einstein vs Newton on Gravity!

Newton discovered the force of gravity about 300 years ago, in which he states that every particle attracts other particles in the universe with a force which is directly proportional to the product of their masses and inversely proportional to the square of distance between them.

His equation was able to calculate the force of gravity accurately without any errors. In fact we are using only the law of gravity during a rocket launch.
Later the equations of universal gravitation takes a different form, which is:

Where F is the gravitational force acting between two bodies, m1 and m2 are the masses of the bodies and r is the distance between the two bodies.

First test of newton's law of gravity was perform by British scientists Henry Cavendish, approximately 77 years after newton's death.

Law of gravitation also provides one of the most useful formula which is inverse square law. This law is same in coulomb's law of electrostatics. In actual this law was prepared by Newton and Robert Hook together.

Everything was going absolutely right until a clerk of Swiss patent office named Albert Einstein propose his special theory of relativity. This theory changes everything in the world of physics.

Einstein confronted the two famous theories of that time which were, newton's theory of absolute space and time and Maxwell theory of constant speed of light.

According to Newton, gravity is an instantaneous force which means we will feel all its effect at the instant at which it starts effecting us. Einstein confronted both these theories by proposing his special theory of relativity.

Einstein propose special theory of relativity, in four  papers in which he explains, how laws of physics didn't change for objects moving in initial frame of reference and also proved the independent speed of light.

Einstein then challenged the newton's concept of gravity as a instantaneous force. Einstein explain this by taking the example of the sun.

Today we know that earth revolve around sun due to its gravitational force and this concept was given by Newton. So lets assume, what happen when suddenly sun disappears?

According to Newton, we will able to know this event at the same instant when sun disappears and our earth starts moving in a straight line motion. Einstein raise his question that if light take about 8 minutes to reach earth then how it is possible that we will feel the absence of sun's gravity in the same instant and if it really happens which means gravity has a greater speed than light, which is impossible.

Einstein then proposes his model of space time fabric. In this model he suggests that if we consider everything (space, matter, energy, time) as a fabrics present in empty space then we will able to find the reason of gravity.

He said that, every heavy mass object make a curve in space time fabric and due to this curve other lesser mass objects starts rotation around the object and same with earth and the sun.

So, when we consider gravity after this space time fabric model then we can clearly visualise that, after disappearing the sun, it will take some time to re-establish the fabric of space time and this time will of course more than 8 minutes.

By this way Einstein proved newton wrong and for doing this he also provide the reason of gravity, which is more important.

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