Be sure to look up at the sky on Christmas Day, because a bright full moon will be an added gift for the holiday. On December 25, the moon will reach its peak size at 6:11 a.m. Eastern Time, just one hour before it sets. The full moon then rises again at 5:32 p.m. on Christmas evening. There hasn’t been a full moon on Christmas since 1977, and this rare event won’t happen again until 2034!
This year’s Christmas moon is the first one of the 21st century. In the 20th century, besides the one that occurred in 1977, there were Christmas full moons in 1901 and 1920. In the 19th century, there were Christmas full moons in 1806, 1825, and 1863 – which was a little more than month after President Abraham Lincoln delivered his famous Gettysburg Address.
The nation’s first Christmas full moon fell on the night of December 25, 1776, when George Washington and his Continental Army crossed the Delaware River to launch a surprise attack on Trenton. Fortunately, dense clouds and a strong winter storm shrouded the bright full moon and hid the army from the Hessians fighting for the British, according to the National Museum of the American Revolution.
Throughout December, the moon is above the horizon for a long time and the full moon has a high trajectory across the sky because it’s opposite a low sun, according to the Farmer’s Almanac. December’s full moon, the last of the year, is called the Full Cold Moon because it occurs at the beginning of winter.
As you gaze up at the Christmas moon, take note that NASA has a spacecraft currently orbiting Earth’s moon. NASA’s Lunar Reconnaissance Orbiter has been circling the moon and sending back data and images of the lunar surface since 2009.
“As we look at the moon on such an occasion, it’s worth remembering that the moon is more than just a celestial neighbor,” said John Keller at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The geologic history of the moon and Earth are intimately tied together such that the Earth would be a dramatically different planet without the moon.”
The Full Cold Moon on Christmas is a fitting way to wrap up a big year in lunar history. 2015 also featured a so-called Super Blood Moon eclipse in September — when a total lunar eclipse coincided with a supermoon, a full moon at the closest point of its orbit to Earth.