Second-order experiments right|thumb|The Michelson–Morley experiment compared the time for light to reflect from mirrors in two orthogonal directions. While the first-order experiments could be explained by a modified stationary aether, more precise second-order experiments were expected to give positive results. However, no such results could be found.
Second-order experiments right|thumb|The Michelson–Morley experiment compared the time for light to reflect from mirrors in two orthogonal directions While the first-order experiments could be explained by a modified stationary aether, more precise second-order experiments were expected to give positive results. However, no such results could be found.