Omar A. Colon Batista: Gravity: Fatherless?

Gravity, by definition is a natural phenomenon by all physical bodies attracts each other. Here on Earth gravity gives weight to all objects giving a downward force to keep them stuck to the ground. Newton, in his study of universal gravitation postulates that the gravitational force of two bodies of mass is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. However Albert Einstein in 1915 published the general theory of relativity that generalizes special relativity and provides a unified description of gravity as a geometric property of space and time, or spacetime. 

Newton postulates that gravity was a force that acts instantaneously plus any distance, but Einstein saw a problem with the theory because it arouse against his work about light and properties of spacetime. So in the contradiction between these to there are now two ways of thinking about gravity and space.

So in Newton’s theory, space is static and flat as Euclid’s law of geometry. Also that objects have a natural tendency to move on straight lines at constant speed. In gravitational force he discovers that there is a force acting on the planets called gravity. This gravitational force depends on a property called gravitational mass, mg (how we can see in the formula of gravitational force). In his second law of motion, that gives the acceleration in response to any force (not just gravity). The acceleration depends on a property that we call inertial mass, like in the formula a=F/m.

However Albert Einstein using his principles and his theory challenges the father of gravity.

In our theory books about physics we see examples like the following: If we are in an elevator, our body has a constant velocity, while the elevator accelerates upward. Another way of thinking, if the elevator is in a constant velocity, the body accelerates downward because of gravity.

In Einstein’s theory of light there are two ways of thinking: If the light has a constant velocity, the elevator accelerates upward. However if the elevator has constant velocity, the light is accelerating downward by gravity in his point of view.

For Einstein gravity affects the paths of photons; even though they have no mass. Mass and energy are interchangeable.

Light takes the shortest distance between two segments. The shortest distance is a straight line in flat space. In the presence of gravity light follows a curved line. So in the presence of gravity, space is not flat, but curved.

In conclusion, in Newton’s theory: gravity depends on the mass, to know how much force to exert. Force tells mass how to move. In Einstein’s theory: mass-energy tells space-time how to curve. So, has gravity’s effect been discovered 100%? Who is right? Has Einstein proved Newton wrong? Who is the true father of gravity?