Dana Horn, writing in Science about Cecilia Payne-Gaposchkin, who discovered that the Sun was made mostly of hydrogen — but is not given proper credit.
Since her death in 1979, the woman who discovered what the universe is made of has not so much as received a memorial plaque. Her newspaper obituaries do not mention her greatest discovery. Even today, when it has become fashionable for historians to highlight the accomplishments of great female scientists, other astronomers are given precedence, or her name is listed as merely one of many. But there is no need to visit an Astronomy Hall of Fame to see how faint the memory of Payne-Gaposchkin has become. A glance at any elementary physical science textbook will do the trick. Every high school student knows that Isaac Newton discovered gravity, that Charles Darwin discovered evolution, and that Albert Einstein discovered the relativity of time. But when it comes to the composition of our universe, the textbooks simply say that the most abundant atom in the universe is hydrogen. And no one ever wonders how we know.
Do yourself a favor and read the whole thing.
(Via Aaron Diaz.)