| MadSci Network: Astronomy |
Jan. 15, 2001 Hi Laura, Thanks for the question! I am fairly sure what you saw on the night of December 29, 2000 was what is called a conjunction, the alignment of two or more astronomical bodies. In this case it was a conjunction between the Moon and the planet Venus, the brightest object in the sky after the Sun and Moon. Venus is often called the "Evening" or "Morning" star; in this case it was in "Evening" star mode. Many reports of UFOs can often be traced to sightings of the planet Venus. The conjunction you saw was a nice one in that the Moon and Venus came fairly close together (about 2.5 degrees) and could be seen at a convenient time of the evening. By the same time the next night (Dec. 30), the objects were separated by 12 degrees, six times as far apart, much less impressive. It will be awhile before Venus and the Moon meet up like this again, and at a much more inconvenient hour as well. On June 17 and July 17, 2001, if you get up before the Sun rises (about 5 AM in SF) you will see Venus as the "Morning" star near the Moon. It will not be until May 14, 2002 that you can view a conjunction of the Moon and Venus at a convenient time (just after sunset) again. Conjunctions can occur between other objects in the sky besides the Moon and Venus. For example, the Moon and Jupiter will appear in conjunction March 29, 2001 just after sunset. Jupiter will only be one sixth as bright as the Venus you saw Dec. 29 but it will still be quite distinctive. Also, the Moon and Jupiter appear near the bright stars of the constellation Taurus and the planet Saturn as well, so this could be considered a multi-object conjunction. Good sources for conjunction information are the many computer programs available that simulate the night sky. To collect the information in this answer I used a program for the Macintosh called Voyager that has a feature called "Conjunction Search". I hope this answer adds to the awe and excitement at your next conjunction! Best Regards, Everett Rubel
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