Subrahmanyan Chandrasekhar calculated the mass limit for white dwarfs at age 19 on a boat to England

Chandrasekhar limit

Chandrasekhar limit is 1.4 solar masses

Henrietta Swan Leavitt

Henrietta Leavitt discovered the period-luminosity relation of Cepheid variables

Neutron stars are so dense that a teaspoon of their material would weigh about 6 billion tons

Neutron stars: teaspoon weighs ~6 billion tons

Stellar black hole

Schwarzschild radius ≈ 3 km for solar-mass black holes

Supermassive black hole

How can a star's mass turn into a cosmic vacuum trap?

Sun

The Sun makes up 99.86% of all mass in the solar system