Complex sentence: In 1887, when experimentalists Michelson and Morley failed to detect aether drift, it was hypothesized that motion "into" the aether prompted aether's shortening, too, as modeled in the Lorentz contraction.
Split into simpler sentences: In 1887, experimentalists Michelson and Morley failed to detect aether drift, however. It was hypothesized that motion "into" the aether prompted aether's shortening, too, as modeled in the Lorentz contraction.