Question on the original Michelson-Morley Experiment

[arunma]

Maybe this has more to do with the history of physics than physics itself. As you all know, the first Michelson interferometer was constructed in 1881. To my knowledge, the experiment requires a coherent source of light. Just wondering, if the experimental apparatus was constructed before the invention of the laser, then how did Albert Michelson produce coherent light?

 

[cesiumfrog]

I'm guessing it was collimated through a sequence of slits.

 

[CPL.Luke]

as long as both beams of light are emitted by the same force, they can be considered coherent.

consider a sun ray, if you break up a sun beam into 2 parts, the two parts are going to be approximately (the difference being very small) identical, and as such can be used to construct interference patterns.

perform a double slit experiment on sunlight to see the effect.

 

[russ_watters]

He used a rotating mirror to create pulses.

 

[siddharth]

A.A. Michelson and E.W. Morley, On the Relative Motion of the Earth and the Luminiferous. Aether
http://www.aip.org/history/gap/PDF/michelson.pdf