Albert Einstein (14 March 1879 – 18 April 1955) explained the anomalous precession of Mercury's perihelion in his 1916 paper The Foundation of the General Theory of Relativity. This led astronomers to recognize that Newtonian mechanics did not provide the highest accuracy. Observations of binary pulsars – the first in 1974 – whose orbits not only require the use of General Relativity for their explanation, but whose evolution proves the existence of gravitational radiation, was a discovery that led to the 1993 Nobel Physics Prize.