Gravitational force is one of the

first fundamental interactions to be discovered and studied by human beings.

Newton in his Principia published in 1687 introduces the law of universal

gravitation which states that an

object attracts every other object in the universe using a force which acts instantaneously, of magnitude that is inversely

proportional to the square of

the distance between them and directly

proportional to the product of

their masses i.e.

We can represent the

gravitational force as coming from a gravitational potential

due distribution of mass density of matter

,

(1)

In 1905 Albert Einstein formulated the special

theory of relativity based on two postulates, the principle of relativity i.e.

the laws of physics have same form in all inertial frames of reference and the

constancy of the speed of light. It’s quite reasonable to think the laws of

physics to be same even in non-inertial frames of reference; this leads us to

the General theory of relativity. We can

extend eq.1 relativistically by replacing laplacian operator by d’Alemvert

operator and mass density by a Lorentz covariant source

Where

is the flat space wave operator and T is the trace of stress

energy tensor. A scalar theory of gravity such as this obeys the postulates of

SR but it doesn’t predict the deflection of light and the right perihelion precession

of Mercury’s orbit 1. However, this

illustrates the need to have a finite velocity for gravitational interactions in

any relativistic gravitational theory. Thus any gravitational waves must be a

natural consequence of any relativistic theory.Gravitational force is one of the

first fundamental interactions to be discovered and studied by human beings.

Newton in his Principia published in 1687 introduces the law of universal

gravitation which states that an

object attracts every other object in the universe using a force which acts instantaneously, of magnitude that is inversely

proportional to the square of

the distance between them and directly

proportional to the product of

their masses i.e.

We can represent the

gravitational force as coming from a gravitational potential

due distribution of mass density of matter

,

(1)

In 1905 Albert Einstein formulated the special

theory of relativity based on two postulates, the principle of relativity i.e.

the laws of physics have same form in all inertial frames of reference and the

constancy of the speed of light. It’s quite reasonable to think the laws of

physics to be same even in non-inertial frames of reference; this leads us to

the General theory of relativity. We can

extend eq.1 relativistically by replacing laplacian operator by d’Alemvert

operator and mass density by a Lorentz covariant source

Where

is the flat space wave operator and T is the trace of stress

energy tensor. A scalar theory of gravity such as this obeys the postulates of

SR but it doesn’t predict the deflection of light and the right perihelion precession

of Mercury’s orbit 1. However, this

illustrates the need to have a finite velocity for gravitational interactions in

any relativistic gravitational theory. Thus any gravitational waves must be a

natural consequence of any relativistic theory.