[STARGAZING] Winter Solstice

Fall ends and winter begins on December 21st, at 8:21 p.m., PST, the Winter Solstice. With only 9 hours, 53 minutes of sunlight at Los Angeles, this is the shortest day of the year. Winter will be followed by spring on the equinox of March 20, 2018.

The Geminid meteor shower, the finest meteor shower this year, should reach its peak during the night and early morning hours of December 13th and 14th, although fewer but brighter meteors may be expected on the previous night, the 12th and 13th. On both mornings, the greatest number of meteors (between one and two per minute from a dark, wilderness location) can be seen around 2 a.m., when Gemini, the constellation from which they seem to stream, is overhead.

Meteors in smaller numbers can be seen through the rest of the night, from 7p.m. until dawn at 5 a.m. The Geminid meteors are not produced by a dusty and icy comet, as are most other meteor showers, but instead are fragments of a stony asteroid that is rotating so rapidly it is disintegrating, an object known as a rock comet. The parent rock comet of the Geminids is called Phaethon, and it will make a relatively close passage of 6.4 million miles from earth on the 10th.

The moon is full on the 3rd, reaches last quarter on the 9th, and is new on the 17th. It will move into the evening sky on the following night and will be first quarter on the 26th. The moon will be a narrow crescent on the best nights of the Geminid meteor shower and will not be bright enough to interfere with viewing.

Although the innermost planet Mercury might be glimpsed briefly in the southwest sky—starting 30 minutes after sunset until the 4th—before it is lost for the rest of the month in the glare of the sun, the only other bright planets now visible can only be seen shortly before and during dawn.

Jupiter is bright and eye-catching in the constellation Libra the Scales. It rises above the east-southeastern horizon at 4:24 a.m. on the 1st, and at 2:53 a.m. on the 31st. The planet Mars is above Jupiter all month and can be recognized by its orange hue.

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