On November 20, 1889, American astronomer Edwin Hubble was born. He is best known for his role in establishing the field of extragalactic astronomy and is generally regarded as one of the most important observational cosmologists of the 20th century.
The Neoplatonian philosopher Hypatia of Alexandria, Egypt, was the first well-documented woman in mathematics. Her actual date of birth is unknown, although considered somewhen between 350 and 370 AD. She was the head of the Platonist school at Alexandria and additionally taught philosophy and astronomy.