The Michelson-Morley Experiment!

So today we will talk about the Michelson-Morley experiment!

''What is this?''

-Well it was an experiment that was made to try and detect the small changes in the speed of light with motion of an observer through the ether. It was performed in 1887 by Albert A. Michelson and Edward W. Morley (obviously!).

''Ok! But what exactly is the Ether and why is that crap important? ''

-Well, during this time, physicists believed that light was a form of wave. Like all kind of waves, it needs a medium to move or propagate through. For example, a water wave needs... water! This is the frame in which water waves move through. Well back in the days they thought that light would propagate through the ether! The ether would have been some kind of medium present everywhere! Right now, you would have been surrounded by ether. Don't worry, it doesn't bite...

''Ok... Now what? ''

-Well lets say you're chilling on earth (like Che is), since the earth is moving at 30 km/s around the sun, we could say that the ether is moving pass you at -30km/s from your point of view. Lets make an analogy here to make it simpler: if the earth is a moving car going straightforward at 30km/s (yeah that's a fast car...) and you are in that moving car(holy shit!), from your point of view, the road would be passing by you at -30km/s. In our analogy, the ether would be the road. Got it? Easy enough right? Che thinks so! Also, Che wants you to remember that the speed of light in free space (or c) is 3 x 10 power 8 m/s.
 
''Ok ok! So what about the experiment? ''

-Well Michelson and Morley made this crap:

                                                       <--------------          Ether movement


Lets say you're in front of this thing and you're watching through the telescope. From your point of view, the Ether would be passing by you at the speed of the earth in the direction shown. Light is produced from the light source. It goes at speed "c" (the speed of light in free space). Since light travels through the ether and the ether is passing by in the opposite direction at the speed of the earth, the speed of light should be "c - speed of the ether" right? The same way that if you're running in an escalator at speed "v" and the escalator is moving in the opposite direction at speed "v2", your total speed from the view point of an observer not on the escalator would be "v-v2". Got that? K. When light is reflected to the half-silvered mirror, it will split in 2 directions. One in the direction opposite of the Ether going at "c-speed of the ether" and the other perpendicular to the ether going at the (c^2 - ''speed of the ether''^2)^1/2 !

''Hmm wait... I don't get how you got the speed of the light beam moving perpendicular to the ether?''

-Yo! It's easy! Remember your good friend Pythagoreas and his Pythagorean theorem? I hope you do! I also hope you know a bit about vectors. Che doesn't have the time to teach you all this stuff right now. But, he will show you how he got it:

Hope you got that!

''Hmmm ok... I think I got it... Now back to the experiment please!''


-Well that will be all for now! Che will explain the rest in his next post! So make sure you tune in for the exciting conclusion of the experiment!

viva la educacion!