I thought they actually measured interference between light beams at 90° to each other. Then they did it again 6 months later. In no case has any relative motion been detected.
I thought they actually measured interference between light beams at 90° to each other. Then they did it again 6 months later. In no case has any relative motion been detected.
Eric Weisstein's website agrees with you.
http://scienceworld.wolfram.com/physics/Michelson-MorleyExperiment.html
I read Michelson's "Studies in Optics"
http://www.amazon.com/exec/obidos/ASIN/0486687007/qid=1028893224/sr=1-6/ref=sr_1_6/102-7194827-7561723 about ten years ago and sort of remember him referring to diurnal measurements, in which the effect should have been immediately apparent. With a 10 foot (3 meter) baseline he should have been able to detect a change in velocity of about only about 1/60th that due to the Earth's rotation. If the speed of light depended on velocity with respect to the source, he should have detected about 30 interference fringe changes in 12 hours.
The Signal to Noise ratio (not the term used in those days) would have been higher in the diurnal measurements usign the sun, the effect would have been more pronounced - more interference fringes - using stars and the Earth's orbital motion, either way it should have been obvious. I'm pretty sure he did both, the latter simply showed that if the "ether" was dragged around the earth as it rotated, it also must be dragged around the Earth in in its orbit.
BTW, Michelson was a relativity skeptic.