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.
Twenty years ago today, Mae Jemison, physician and NASA astronaut, became the first black woman to travel in space aboard the Space Shuttle Endeavour. Jemison has launched 100 Year Starship, an ambitious project to encourage interstellar travel through the exchange of creative ideas. When Jemison was an undergraduate at Stanford University, her roommate was Linda Lorelle, who went on to become a KPRC-TV anchor.