If you missed December’s biggest full moon of 2008, tonight will be the biggest full moon of 2009. NASA has a nice article about it.
Johannes Kepler explained the phenomenon 400 years ago. The Moon’s orbit around Earth is not a circle; it is an ellipse, with one side 50,000 km closer to Earth than the other. Astronomers call the point of closest approach “perigee,” and that is where the Moon will be this weekend. Perigee full Moons come along once or twice a year. 2008 ended with one and now 2009 is beginning with another. It’s the best kind of dÃ©jÃ vu for people who love the magic of a moonlit landscape. January is a snowy month in the northern hemisphere, and the combination of snow + perigee moonlight is simply amazing. When the Moon soars overhead at midnight, the white terrain springs to life with a reflected glow that banishes night, yet is not the same as day. You can read a newspaper, ride a bike, write a letter, and at the same time count the stars overhead. It is an otherworldly experience that really must be sampled first hand.