... 1950, Edith Sampson (right), 49, became the 1st African-American delegate to the United Nations to hold the position, having been appointed an alternate delegate by President Harry S. Truman. This was among many 1sts in her career: she was the 1st woman to graduate from Chicago's Loyola University School of Law; the 1st African-American woman elected a judge in the United States; and the 1st African-American to be named a member at large of NATO.
... 2006, in a move that rendered longstanding notions of the solar system obsolete, the nongovernmental organization International Astronomical Union determined that Pluto is not a planet, as schoolchildren'd been told for decades. That celestial body -- named in 1930 on a suggestion from 11-year-old English schoolgirl Venetia Burney (above) -- is now classified as a "dwarf planet," along with other bits and pieces orbiting the sun.