What waas the Michelson-Morley experiment?

Answer 1

The M-M experiment was an optical interferometer. An interferometer is a device that splits a beam of monochromatic light in two, sends each along different paths, and then recombines them. Each time the interfering beams pass from constructive to destructive interference means that one path has increased the number of wavelengths traveled relative to the other by 1. M-M made the different paths orthogonal and rotated the whole interferometer by 90 degrees and observed that the number of wavelengths in each path remained equal to each other. This implies that the speed of light does not depend on direction. Since the earth is known to rotate and move around the sun, the result implies that the speed of light relative to the interferometer does not depend on this motion, as would be the case if there were a fixed medium that light propagates in at constant velocity, and through which the earth moves (a popular hypothesis of the time).

Answer 2

The concept of the aether has been around a long time. It is a mythical substance supposed to fill all of space. ('Ether' is a modern spelling. The aether is NOT the same as the organic compound ether - it's unfortunate that they use the same name. I believe both names derive from the same root though - look up 'ethereal'; ether is very volatile and forms a gas that spreads everywhere.) To explain how electromagnetic waves (like light) are transmitted, 19th century scientists used the 'aether' . The concept was used because physicists could not understand how light could be a wave without some sort of substance to be vibrating. The whole of space was supposed to be filled by the aether; electromagnetic wave were simply vibrations of the the aether. (EM waves are now explained by the changing magnetic and electric fields which can exist in a vacuum). The universe was suppose to be filled with the aether. If this were true, it should be possible to measure the earth's speed relative to the aether. The ether frame is simply the frame of reference (coordinate system if you like) that the earth is supposed to be moving reative. An inertial frame of reference is one which is not accelerating, e.g. the coordinate system inside a rocket moving at a steady speed in a straight line. I can't attempt to explain the Michelson-Morley experiment briefly or without diagrams. Take a look at the 3 part video in the links (skip 1st minute and a half of part 1- nothing happens).

Answer 3

I consider the M-M experiment to be most simplest, elegant, and profound observations ever made ... ( though only a few of us know about it ! ).

Thereby, let me go ahead and explain it for you ( labor of love ).

Essentially, the M-M exp. shows that the speed of light is constant NO matter the speed of the observer.

It was done using two perpendicular beams of light and taking their speed relative to the rotational motion of the earth. It turns out that the speed of light is fixed and unaffected by the motions of the light source or the observer.

This experiment disproved the presence of an "ether" which was a medium that carried light thru space. This exp. also confirmed Einstein's theory that light travels at a constant speed.

No other experiment shows the profound meaning of the relative nature of space and time in such a simple and beautiful observation.

thanks :)

Answer 4

cirric is right, it was an experiment to detect the "ether", which was supposed to be the absolute refference frame from which all velocities would be measured. It was also supposed to be the medium which light travelled through. The experiment failed to detect the ether, and it paved the way for Einstein to come up with Special Relativity.

Answer 5

What Waas

Answer 6

Hi. It was a test using straight beams at 90 degrees of angle to demonstrate that the Earth was moving through an 'aether'. The experiment is most famous because it failed.

Answer 7

Here is a good description http://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_experiment