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.
Richard T. Greener, First Black Harvard Alum, Diploma Discovered In Condemned Chicago House. An abandoned home near 75th and Sangamon, on Chicago's South Side, was the unlikely hiding place for an important piece of black history -- the papers of Richard Theodore Greener, Harvard's first African-American alumnus.