1812 - 8.2 earthquake shakes New Madrid, Missouri
1889 Astronomical Society of Pacific holds 1st meeting in SF
1979 - Pluto moves inside Neptune's orbit for the first time since either was discovered.
1984 - Space Shuttle Challenger lifts off for mission STS-41-B - Astronauts Bruce McCandless II and Robert L. Stewart make the first untethered space walk using the Manned Maneuvering Unit (MMU).
1992 - The Maastricht Treaty is signed, leading to the creation of the European Union.
