Reference: Essays on Substance
Michelson-Morley’s Null Result
The prevailing aether theory at the time of the Michelson-Morley experiment in 1887 was that a hypothetical medium called luminiferous aether permeated all of space. This theory posited that:
- Aether was a stationary substance that filled empty space.
- Light waves required this aether as a medium to propagate, similar to how water waves need water and sound waves need air.
- The Earth was believed to move through this stationary aether as it orbited the Sun.
This theory predicted that the Earth’s motion through the aether would create an “aether wind,” which would affect the speed of light in different directions relative to Earth’s movement. The Michelson-Morley experiment was designed to detect this aether wind by measuring potential differences in the speed of light traveling in perpendicular directions.
The expected difference between the speed of light in the direction of movement through the presumed aether, and the speed at right angles, was found not to exist. The null results from Michelson-Morley experiment initiated a line of research that eventually led to Einstein’s theory of Special Relativity. The special relativity then ruled out a stationary aether, and postulated the velocity of light to be absolute.
According to the theory of Substance, there has to be substance filling existing space. In the absence of matter and energy, it has to be some undefined substance, which we may call aether. The consistency of this aether is very likely many orders of magnitude lesser than the consistency of light. Therefore, it would offer no resistance to the movement of either light or Earth.
Earth is made of solid particles (atoms), whereas, light is made of gaseous particles (not waves in some medium). The only resistance that Earth and light would encounter is due to their respective inertia. Newton defined inertia as follows:
“The vis insita, or innate force of matter, is a power of resisting by which every body, as much as in it lies, endeavours to preserve its present state, whether it be of rest or of moving uniformly forward in a straight line.”
The inertia balances the respective motions of Earth and light, such that, their respective velocities are constant. Therefore, the ratio of their velocities shall be the inverse of the ratio of their inertia or consistencies. According to The Spectrum of Substance, the consistency of light is around 49, and the consistency of Earth (average per particle) is around 80.
The difference in their consistencies is 31, which gives us a ratio of 231 or about 109. The Earth’s drift speed in space is 10-9 times the speed of light, or less than half a meter per second.
The Michelson-Morley’s experiment is then required to detect a velocity difference of less than half a meter per second in the velocity of light (3 x 108 m/s) due to the difference in motions of the Earth. This would be a shift in fringes of the order of 10-9 meters. That is of the order of the size of an atom. This explains the null result produced by Michelson-Morley experiment.
NOTE: The consistency of earth may be underestimated here. It may require much greater precision than 10-9 meters to detect a shift in the fringes obtained.
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