One was the Chandrasekhar limit. In 1930 Wilhelm Anderson and E. C. Stoner wrote a paper about the limit which they named after Chandrasekhar because he was the one who discovered it(when he was 19!). People didn't believe his limit when he discovered it because it means black holes must exist, which people didn't believe at the time. There is a number named after him but it's too scientifically complicated for my brain to process at this point.