Michelson and Morley Aether Experiment

[midgetwars]

Homework Statement

Well. the statement is explain the Aether Experiment.

Homework Equations

The Attempt at a Solution

What i gather is that MM threw a light source into a thing to split the light up and had to mirrors to reflect the light into the telescope. One going against and one going perpendicular to the aether. What i don't get is the Results.

How do the results work?? If there is an aether what would the difference be if there wasn't and what is the point of swiveling the whole thing 90degrees? I know the results was like this black and white interference image but i don't understand fully

 

[NobodySpecial]

The black and white fringes show that the light took the same time to travel along the two different arms and back (or rather the fact that the fringes don't move shows this)

If the light was traveling through an eather then the light that was going with the movement of the Earth would get a boost and so take a shorter time - rotating it 90deg is so you can take out any difference in the instrument or any local effects.

Think of it as comparing the time taken for two people to swim a river , one going with the current and one going across the current.

 

[midgetwars]

So if there was an aether what would be different in the black and white fringes??

 

[NobodySpecial]

They would move as the instrument rotated - or as the Earth rotated, or moved around the sun, or the sun around the galaxy ...

 

[midgetwars]

Why?? Wouldn't without rotating it would be changed already??

Without moving in 90degrees what would be telling of that the aether does not exists?

 

[NobodySpecial]

Well you don't know what direction you are moving through the invisible aether (ie what direction the current is flowing in) so they did the experiment 6months apart, so they were moving in opposite directions around the sun.

Rotating the rig 90deg in the lab was just in case there was some local effect that changed the lengths of the arms differently, perhaps one side of the room was warmer, or one side of the table bent more.