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Week 52


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 …

Perihelion: 2011 December 16.08, q = 0.006 AU  In the “Special Topics” presentation on Kreutz sungrazers eight weeks ago I mentioned that in 2007 Zdenek Sekanina and Paul Chodas published a paper wherein they predicted that a new “cluster” of sungrazers should be arriving within the next few decades, with “its earliest member possibly just several …

Ever since humankind began to discern the overall structure of the solar system a few centuries ago, i.e., that the sun basically resides in the center and the planets orbit around it, this has brought forth questions, for example, how did the planets, and the solar system as a whole, form? A second question would …