On January 4, 1643, Sir Isaac Newton, famous physicist, mathematician, astronomer, natural philosopher, alchemist and theologian, was born. With his Principia he laid the foundation of modern classical mechanics.Besides he constructed the very first reflecting telescope and independent f Gottfried Wilhelm Leibniz developed differential and integral calculus.
On December 19, 1859, US-american physicist Albert Abraham Michelson was born. Together with his colleague Edward Williams Morley he conducted an experiment that proved the by the time famous ether theory to be wrong and is considered to be one of the pilars of the theory of relativity.
The atomic number uniquely identifies a chemical element. This discovery is thanked to the British physicist Henry Moseley, who justified this empirical and chemical concept of the atomic number also from physical laws.