July 25, 1978

A Big Mac cost $0.83 that summer of 1978, and the Dow Jones sat at 805 — while NATO and the Soviet Union traded warnings over African conflicts and arms reductions in central Europe, the Cold War remained a constant backdrop to ordinary American life. On movie screens and radio stations, "Grease" was the top-grossing film of the summer with John Travolta and Olivia Newton-John drawing massive crowds, while Andy Gibb held the number-one spot on the charts with "Shadow Dancing." On June 22, astronomer James Christy at the U.S. Naval Observatory discovered Charon, a previously unknown moon orbiting Pluto, marking the first major addition to the known Pluto system and expanding humanity's understanding of the outer solar system.