A Theory of Ether
In an effort to explain how electrical forces affected small objects,
Rene Descartes, philsopher and scientist, proposed the idea if "ether".
He used the concept of ether to explain how a charged object could pick
up pieces of paper even when they were not touching it.
Newton discovered the equation how charged particles interacted with
F = kQq / r2
However, he could not explain how the force was transferred from one
body to another. Nowadays, we know this force to be an electric field.
Therefore, in 1650, Descartes proposed that there was an invisible
medium in space called "ether". It had no mass and was not visible to
the naked eye. He stated that a charged obkect could set up vortex
motions in this ether, and these vortexes would travel to other
particles and exert forces on them.
Up to the early 1800's, ether was believed to be the medium that all
waves, including light, travelled in. Ether pervaded all matter and
energy in the universe. With Maxwell's Wave Equation (which won't mean
a thing if I typed it out), it was inferred that the velocity of the
light wave would equal 'c' (the speed of light, 3.00 *10^8 m/sec) only
with respect to the Ether. Ether was stated as being an absolute frame
A particle at rest with respect to the ether would be considered "at
absolute rest" and a particle with respect to the ether in motion was
said to be "in absolute motion".
Ether had to be extremely rigid for light to propogate to such enormous
speeds, but yet, it could NOT impede the motion of other bodies. This
was believed to be somewhat radical, and thus, A.A. Michaelson decided
to try to detect the Earth's motion relative to the Ether. He predicted
that if the earth moved relative to the Ether, there would be an "ether
wind" that would move at the same speed relative to the earth, but in
the opposite direction. By measuring the changes in the speed of light
parallel and perpindicular to the "Ether Wind", he would be able to
detect the motion of the earth. If the speed of light changed, then
there would certainly be an Ether Wind.
The results of his experiments were inconclusive. He received
different values, but the error was so slight that he believed that it
could have been another factor instead of the "ether presence".
Repeated studies today have reduced the error, but the value for the
speed of light is still not exactly the same.
These measurements of light in a relative frame was the basis for the
aspects of the Theory of Relativity.