ok, let me restate the experiment i was refering too:
scientists were arguing about whether light is a wave or a particle.
if light is a wave, what is it a wave IN? you can't have water-type waves without water, can you? and sound waves are vibrations in the air, so light could be...vibrations in the aether.
so they set up their experiment to see if light moving the SAME way the earth was moving would appear to move faster than light moving the OPPOSITE direction or SIDEWAYS.
their conclusion: light always travels at the same speed, and therefore should be a particle. this SEEMS to disprove the existince of aether, but I could be mis-interpreting.
on the other hand, of you shine light through 2 polarized lenses, then turn one of them 90 degrees, NO light gets through both, which means light must be a wave!
this was before einstein, btw. his explanation...i guess i should look it up.