In 1887, one of the most important experiments in the history of physics took place. American scientists Michelson and Morley failed to measure the speed of Earth by comparing the speed of light in the direction of Earth’s motion with that perpendicular to it. That arguably most important zero measurement in the history of science led Einstein to postulate that the speed of light is constant and consequently to formulate his theory of special relativity.

This theory implies that all laws of physics are the same, independent of the relative motion between observers—a concept known as Lorentz invariance.

Meanwhile, quantum theory has been developed, with Lorentz invariance at the heart of all its theoretical frameworks, in particular quantum field theory and the Standard Model of Particle Physics. The latter is the most precisely tested theory ever developed and has been verified to incredible precision.