Jupiter-Saturn Conjunction 2020-1221

    Jupiter and Saturn made their closest approach in 397 years, a separation of 6.1 arcminutes, on Dec. 21, 2020 (also the day of the Winter Solstice). The last time they were closer (5.1 arcminutes) was July 16, 1623,  during the career of Galileo Galilei. However that event likely went unobserved, as the planets were lost in the glare of the sun.

     Previous to that, a closer encounter of 2.1 arcminutes occurred on March 4, 1226. The next time they will appear as close as 1 degree of arc (approximately two Moon widths) will be on Nov. 2, 2040 and April 7, 2060. On March 15, 2080, they will be 6.0 arcseconds apart - about the same separation in 2020.

     As this happens during the holiday season, speculation is rekindled that a similar conjunction on December 5, 7 BCE (the third of three Jupiter-Saturn conjunctions that year) may have been the Biblical "Christmas Star," an idea originally advanced by Johannes Kepler. According to the Biblical account in Matthew, a bright star (implied to be unusual or temporary) guided the Wise Men from the East to King Herod of Judah, and eventually the Messiah.     Sources: timeanddate.com, almanac.com, astropro.com, wikipedia.com