Michelson-Morley experiment, an attempt to detect the velocity of the Earth with respect to the hypothetical luminiferous ether, a medium in space proposed to. The Experiments on the relative motion of the earth and ether have been completed and the result decidedly negative. After the "failed" experiment Michelson and Morley ceased their aether drift measurements and started to use their newly developed technique to establish the wavelength of light as a standard of length.‎Albert A. Michelson · ‎Edward W. Morley · ‎Aether theories. A bit of history: Michelson. When Clerk Maxwell wrote to D.P. Todd of the U.S. Nautical Almanac Office in Washington in , he inquired about the possibility of.


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Lord Rayleigh wrote to Michelson, urging him to repeat the experiment with greater accuracy to test these hypotheses.


Repeated over the next 40 years with ever greater precision and the same negative result, this experiment is pointed to as one of the experimental foundations of relativity, and earned Michelson the Nobel Prize in Unfortunately, our editorial approach may not be able to accommodate all contributions.

Michelson and Morley mounted their apparatus on a stone block floating in a pool of mercury, and rotated it to seek changes in relation to the motion of the earth in its orbit around the sun.

Michelson and Morley were able michelson morley experiment measure the speed of light by looking for interference michelson morley experiment between the light which had passed through the two perpendicular arms of their apparatus.

These would occur since the light would travel faster along an arm if oriented in the "same" direction as the ether was moving, and slower if oriented in the opposite direction.

This aether must also fill all of space, out to the stars, because we can see them, so the medium must be there to carry the light. We could never hear an explosion on the moon, however loud, because there is no air to carry the sound to us.

Let us think a michelson morley experiment about what properties this aether must have. Since light travels so fast, it must be very light, and very hard to compress. Yet, as mentioned above, it michelson morley experiment allow solid bodies to pass through it freely, without aether resistance, or the planets would be slowing down.

Thus we can picture it as a kind of ghostly wind blowing through the earth. But how can we prove any of this? Can we detect it? Detecting the Aether Michelson morley experiment Naturally, something that allows solid bodies to pass through it freely is a little hard to get a grip on.

Michelson-Morley experiment

But Michelson realized that, just as the speed of sound is relative to the air, so the speed of light must be relative to the aether.

This must mean, if you could measure the speed of light accurately enough, you could measure the michelson morley experiment of light travelling upwind, and compare it with the speed of light travelling michelson morley experiment, and the difference of the two measurements should be twice michelson morley experiment windspeed.

All the recent accurate measurements had used light travelling to a distant mirror and coming back, so if there was an aether wind along the direction between the mirrors, it would have opposite effects on the two parts of the measurement, leaving a very small overall effect.

There was no technically feasible way to do a one-way determination of the speed of light. At this point, Michelson had a very clever idea for detecting the aether wind.

Michelson–Morley experiment - Simple English Wikipedia, the free encyclopedia

As he explained to his children according to his daughterit was based on the following puzzle: Suppose we have a river of width w say, feetand two swimmers who both michelson morley experiment at the same speed v feet per second say, 5 feet per second.

The river is flowing at a steady rate, say 3 feet per second. The swimmers race in the following way: