Theory of relativity

When you talk about relativity you are actually talking about two theories: the theory of general relativity and the theory of special relativity. Both were introduced by scientist Albert Einstein in the early 20th century. Like any new explanation, this one also arose from a question that could not find an answer: how to combine the electromagnetism formulated by Maxwell and Newtonian mechanics.

The two theories of relativity laid the foundations of modern physics and thanks to them we were able to better understand the functioning of the universe, as well as the structure of space and time.

Contrary to what could be think, Einstein did not receive the Nobel Prize for relativity but for the photoelectric effect, a experiment which demonstrated why light could extract electrons from a metal.

General relativity

His main contribution was the correlation of gravity and the dimensions of space-time

This correlation can be explained by the tendency to maintain a state of

movement, something that happens when an elevator accelerates or decelerates due to the force of inertia.

According to this theory, space and time are closely related. The structure of both is dynamic and not static as was believed until then. In this way, space-time could be deformed according to the velocity applied. This new idea is precisely what bases the concept of relativity.

In summary, the theory of general relativity explains that the curvature of space-time is determined by the amount and type of Energy that is locked in space-time. In turn, the curvature of space-time affects the way energy flows in space.

Special relativity

This theory arose after asking two fundamental questions: what would happen if an object ran at the same speed as light? And would the light be stationary or at a slower speed?

To answer these questions, Einstein presented four great premises:

1) According to the speed of an object, its mass increases. Thus, it will not be possible to exceed the speed of light, since increasing the speed of the object must proportionally increase energy to move more mass, to the point of needing energy infinite.

2) Time and space expand. In this way, for the speed of light to be the same if you see it standing or approaching it, space-time needs to be expanded in relation to speed.

3) Time is not absolute and simultaneity does not exist. Everything is relative to the eye of the beholder who perceives it. What may seem like a second to someone may seem like a year to someone else if you vary your gravitational mass and speed.

4) Mass is a form of energy. Energy equals mass times acceleration squared.

Photos: Fotolia - Bitter / Matiasdelcarmine

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