A supermoon occurs when the moon is full and at its closest point to Earth in its 27-day orbit. December’s full moon follows November’s full Beaver Moon and October’s full Hunter’s Moon — both of which are also supermoons. In fact, November’s full moon was the closest to Earth since 1948, and the full moon won’t come that close again until Nov. 25, 2034.
Tonight’s supermoon also coincides with this year’s Geminid meteor shower, and, as with any full moon, the bright light will obscure some of the fainter shooting stars in the Geminids. A supermoon appears about 30 percent brighter in the sky than a full moon that’s positioned at its farthest distance from Earth. The full moon will reach its peak fullness tonight at 7:05 p.m. EST (0005 GMT on Dec. 14), but it will appear full to the casual observer the night before and the night after the main event. [Supermoon December 2016: When, Where & How to See It]
Credit: Karl Tate/SPACE.com
The full moon of December was named the full Cold Moon, as it is associated with cold winter nights in the Northern Hemisphere, according to The Old Farmer’s Almanac. The full moon also received the moniker Long Nights Moon because it occurs near the winter solstice — the shortest day of the year and the beginning of winter, which falls on Wednesday, Dec. 21, this year.
The December full moon is the third supermoon in a row (after the supermoons of October and November), and it’s the last chance skywatchers will have to see a full moon before 2016 comes to a close. A webcast featuring live views of the supermoon will be available online through the Virtual Telescope Project, starting at 11 a.m. EST (1600 GMT) on Dec. 13.