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 the Chandrasekhar Limit. That 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.