Special theory of relativity

In 1905, German Albert Einstein published two hypotheses:
1. The laws of physics are identical for all observers moving at a constant speed.
2. The speed of light in a vacuum is identical for all observers.
In doing so he solved a fundamental problem, which was how it was possible that there was no medium that made the propagation of light possible. Without this medium, also called the ether, it would have been impossible to explain how light waves from the sun and stars reached Earth.

It was known at that time that light spreads in the form of a wave. The prevailing belief was that waves needed a medium, just as sound needed air. But there is no air in space. However, we see the light of the stars and planets in the sky. Then space would be filled with a medium we had not yet discovered, was the logical line of thought. Surprisingly, there were no experiments capable of measuring this method.

Suddenly, Einstein appeared with his special theory of relativity based on the two aforementioned hypotheses. It turns out that light waves do not need a medium. Light is a wave that can exist in a vacuum. The necessity of the ether disappeared in one fell swoop. (However, the longing for ether will continue for many years to come. Scientists can be very stubborn.)

His assumptions were not without consequences. Because how can the speed of light be the same for all observers? If one observer moves away from the light source and another observer moves toward the light source, they should measure different speeds of those light waves, right? It only seems logical. This is exactly the problem. The way we think depends on our daily experience of the world. We often don’t realize that things could be done differently. To understand relativity you have to start by thinking in terms of experiments and observations.

In my new video, I show how the theory of relativity conflicts with our intuitions of time and space.