Mode:Null result / no ether Angle:0.0° Expected fringe shift:0.000 Interpretation:No shift as apparatus rotates.
Key idea:
A light beam is split into two perpendicular arms.
The two beams reflect from mirrors, return to the beam splitter, and recombine to form interference fringes.
If Earth moved through a stationary ether, the round-trip times in the two arms should change as the apparatus rotates.
Historical result:
Michelson and Morley expected a fringe shift if ether wind existed.
The observed result was essentially zero shift, which helped undermine the ether idea and later supported Einstein’s relativity.