Celestial ‘wonders’ set to occur in December
As the “Third Rock” completes another orbit of the sun, December brings several celestial wonders for earthlings. Planets Saturn, Jupiter and Mars adorn the evening skies, one of the best annual meteor showers peaks and the seasons change.
“The Red Planet, Mars, is our star performer this month,” said astronomer Mark Steven Williams. “Every 26 months Mars reaches opposition in our skies. Opposition is defined as ‘the moment a solar system body has a celestial longitude differing from that of the sun by 180 degrees.’
“In other words, the planet is opposite our star, rising at sunset and setting at dawn,” he said. “This generally applies to the solar system’s ‘superior’ planets, which are beyond Earth’s orbit.”
This time around, Mars reaches opposition on Dec. 8. This evening (Wednesday) the full moon will pass in front of Mars in a rare, remarkable “occultation” that will be observable across much of North America and Europe, Williams said.
“Here in Southern Indiana, Mars will disappear behind Luna from approximately 10:20 to 10:45 p.m. EST,” he said. “The Red Planet’s disappearance will happen earlier at locations to the west and hours later in Europe.”
Six nights later, Dec. 13, the Geminid meteor shower will peak.
“The Geminids is the most prolific shower of the year with more than 100 meteors per hour under dark skies,” Williams said. “Unfortunately, the 70% illuminated waning gibbous moon will rise about 9:30 p.m. the 13th and brighten the sky. Meteor activity will still be good the 14th, and Luna will rise an hour later. Go out at dusk either evening.”
Winter will begin in the Northern Hemisphere at 4:48 p.m. on Wednesday, Dec. 21, the winter solstice. The 21st is the longest night of the year with 14 hours and 57 minutes of darkness.
“Interestingly, earliest sunsets, 5:23 p.m., are Nov. 30 to Dec. 13 and latest sunrise, 8 a.m., the first 10 days of January locally,” Williams noted.
Williams added, “To make this evening (Dec. 7) even more spectacular, the International Space Station will make a six-minute visible pass overhead at 6:05 p.m. The ISS will pass northwest to southeast peaking nearly overhead at 6:08 p.m.”
Weather is the greatest concern regarding the Mars occultation and Geminids. Visit the StarGeezer Astronomy Facebook page for more information about the occultation, meteor shower and updated clear sky forecasts or send an email to [email protected] with questions.
“The Mars occultation is a very rare event that happens about once every 14 years,” Williams said. “Bundle up, go out and enjoy Mars’ disappearing act and these celestial delights above the glow of Christmas lights.”