Relativity

Ether

theoretical substance that scientists said the speed of light was relative to 

Michaelson-Morley experiment

failed to show that the speed of light can change

Albert Einstein

came up with the theory of relativity

Time dilation

due to the effects of relativity, something moving past you at very fast speeds will appear to experience less time than you do

Length contraction

due to the effects of relativity, moving objects appear shorter in length compared to how they appear when stationary

Lorentz factor

γ=1/√(1-v²/c²)

Speed of causality

c, the ultimate speed of the universe; one event cannot influence another separate event any sooner than information can travel between the two events at the speed of c

On the Electrodynamics of Moving Bodies

Einstein’s paper that introduced the theory of relativity

Electromagnetic force

a fundamental force that can appear as the electric force from certain frames of reference and as the magnetic force for other frames of reference