Chapter 16, Problem 20A

Does Einstein’s theory of gravitation invalidate Newton’s theory of gravitation? Explain.

To determine

To explain: Whether Einstein’s theory of gravitation invalidate Newton’s theory of gravitation or not.

Explanation of Solution

Introduction:

One of the best outcomes from the scientific world in 16^th to 17^th century is the discovery of gravity. Among various natural phenomenon, gravity is the milestone in the history of science. Every massive body connected to another massive body through the force of gravity. Gravity plays its role from stability of the human on the surface of the earth to the formation of the stars, in the universe.

In 1687, Newton discovered the universal gravitational law. According to Newton, force which keeps planet revolving around the sun is inversely proportional to the square of the distance between planet and sun. Mathematically it can be expressed as,

  $F=G\frac{M_1{M}_2}{r^2}$

Where, M₁and M₂are the masses of the objects and r be the distance between them. Newton clearly explained the motion of planet, object moving on the earth’s surface and many more. But description of shifting of mercury’s orbit cannot explained by the Newton. Orbit of the mercury around the sun makes the discrepancy in Newton’s law. The problem related to this Mercury’s orbit solved by the Einstein’s general theory of relativity in 1915. According to Einstein, not gravity but space-time curvature around the object makes well shape. In that well shape, objects even light also fall. This Einstein’s view of gravity solves the problem of mercury. Due to the simplicity of the Newton’s law of gravity, many of the problem can be solved by simply Newton’s laws of gravity. When the speed of the body is comparable to speed of light, Newton’s law cannot hold more. In that case, relativity theory works very well.

Conclusion:

Therefore, the Newton’s law of gravity is the natural phenomenon where many of the problems can be solved with this theory. But when the speed of the object reaches to the speed of the light, Newton’s law replaced with the Einstein’s theory of the gravity. So, Einstein’s theory of gravitation not invalidate the Newton’s theory of gravity.