Karl Schwarzschild (/'shvarts shĭld/) (October 9, 1873 – May 11, 1916) was a German physicist. He is also the father of astrophysicist Martin Schwarzschild.
He is best known for providing the first exact solution to the Einstein field equations of general relativity, for the limited case of a single spherical non-rotating mass, which he accomplished in 1915, the same year that Einstein first introduced general relativity. The Schwarzschild solution, which makes use of Schwarzschild coordinates and the Schwarzschild metric, leads to the well-known Schwarzschild radius, which is the size of the event horizon of a non-rotating black hole.
Schwarzschild accomplished this triumph while serving in the German army during World War I. He died the following year from pemphigus, a painful autoimmune disease which he developed while at the Russian front.
Asteroid 837 Schwarzschilda is named in his honor.