An element is a chemical substance made up of a particular kind of atom and hence cannot be broken down or transformed by a chemical reaction into a different element, though it can be transmuted into another element through a nuclear reaction.
Almost 40 years separate Shirley Ann Jackson's achievement, as the first African-American woman to earn a Ph.D. in theoretical high energy physics at Massachusetts Institute of Technology, and Jedidah Isler, the first African-American woman to receive a Ph.D. in Astrophysics from Yale.
Christine Darden. Dr. Christine Darden (born September 10, 1942) is an American mathematician, data analyst, and aeronautical engineer who devoted her 40-year career in aerodynamics to researching sonic booms at NASA. She was the first African-American woman at NASA's Langley Research Center to be promoted into senior executive service. Darden is one of the women scientists featured in Hidden Figures, a book by Margo Lee Shetterly published in 2016.