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DECEMBER 27, 1984: A team of American meteorite hunters finds the meteorite ALH 84001 in the Allan Hills region of Antarctica. This meteorite was found to have come from Mars, and in 1996 a team led by NASA scientist David McKay reported the presence of possible “microfossils” and other evidence of potential biological activity within …

DECEMBER 20, 1900: Michel Giacobini at Nice Observatory in France discovers the comet now known as Comet 21P/Giacobini-Zinner. This is the parent comet of the Draconid meteor shower and is also the first comet to be visited by a spacecraft; it is a previous “Comet of the Week.”  DECEMBER 21, 1969: Comet Tago-Sato-Kosaka 1969g passes …

DECEMBER 13, 2012: China’s Chang’e 2 mission encounters the Apollo-type asteroid (4179) Toutatis, coming to within 3.2 km of the asteroid. Chang’e 2 and other missions to the solar system’s “small bodies” are discussed in a previous “Special Topics” presentation.  DECEMBER 14, 1807: A meteorite falls to the ground near Weston, Connecticut. An ordinary chondrite, …

DECEMBER 6, 1997: Jim Scotti with the Spacewatch program in Arizona discovers the Apollo-type asteroid now known as (35396) 1997 XF11. This asteroid created a major stir the following year when orbital calculations indicated a very close approach to Earth would be occurring in October 2028, and even though subsequent calculations with more data moved …

NOVEMBER 29, 1996: A team of researchers led by Stewart Nozette publishes their paper describing the tentative detection of water ice at the moon’s south pole in radar experiments conducted with the U.S. Defense Department’s Clementine spacecraft. This detection has been confirmed by later spacecraft missions, and these efforts, and the overall significance of this …

NOVEMBER 22, 2020: The Apollo-type asteroid (7753) 1988 XB will pass 0.066 AU from Earth. The best visibility will be next week when it travels west-northwestward through Leo, Cancer, and Gemini and will be 15th magnitude. Close approaches by near-Earth asteroids are the subject of this week’s “Special Topics” presentation.   NOVEMBER 25, 2005: JAXA’s Hayabusa …