On this day in 1910 - October 19th - Indian-American astrophysicist and Nobel laureate Subrahmanyan Chandrasekhar was born.

He's known for his work in stellar evolution including black holes. The Chandrasekhar Limitt is the dividing line between the mass of a star that has spent its nuclear fuel and will collapse into a white dwarf and one massive enough to go out with a bang - a supernova. It's about 1.4 times the Sun's mass.