Friday, December 12

Look Up!

Tonight's full moon, assuming no clouds, is the biggest and brightest to be seen for 15 years. As Arthur recounts, each month the moon makes a full orbit around the earth in a slightly oval-shaped path, and tonight it will swing by at its closest distance, or perigee, passing 221,595 miles away - 17,400 miles closer than average. What's unusual tonight is that the perigee coincides with a full moon making it appear 14% bigger and 30% brighter than most full-moons (the next closest encounter BTW is November 14, 2016 but it won't be a full-moon). Tonight's moon is also notable for rising to its greatest height in the night sky, lying almost overhead at midnight. This is due to the approaching winter solstice on December 21 and, thanks to the tilt of the earth, the moon appears at its highest as the sun is at its lowest. Were that not enough, tonight and for the next several nights is the Geminid meteor shower, one of the year's best displays of shooting stars - up to 100 meteors an hour can fly across the sky. Cool!
Moon photo from National Geographic.