Eetterijärjestelmät

Eetterijärjestelmät refer to theoretical frameworks proposing the existence of a pervasive medium, the luminiferous aether, that was once believed to permeate all of space and serve as the vehicle for light propagation. Early in the development of physics, before the advent of relativity, light was understood as a wave phenomenon. Analogous to other waves like sound or water waves, it was assumed that a medium was necessary for these waves to travel. This hypothetical medium was named aether.

The concept of aether was invoked to explain how light could travel through the vacuum of space. It was thought to be a substance that was both extremely rigid, to support the high speed of light, and yet completely intangible, to allow planets and other celestial bodies to move through it without resistance. Numerous experiments were devised to detect the motion of the Earth through this aether, most famously the Michelson-Morley experiment. This experiment, conducted in 1887, aimed to measure the speed of light in different directions relative to the Earth’s assumed movement through the aether.

The results of the Michelson-Morley experiment were null, meaning they failed to detect any difference in the speed of light, regardless of the direction. This unexpected outcome posed a significant challenge to aether theories. Subsequent developments in physics, particularly Albert Einstein's theory of special relativity, provided a new framework that did not require a luminiferous aether. Relativity postulates that the speed of light in a vacuum is constant for all inertial observers, a principle that successfully explained the experimental observations without the need for a hypothetical medium. Although the concept of a luminiferous aether has been largely abandoned in modern physics, it played a crucial role in the historical development of our understanding of light and space.