The last time a full moon appeared on Christmas Day, Han Solo and Chewbacca were fighting Stormtroopers in "Star Wars."
OK, so not everything has changed. But Friday will be the first full moon on Christmas since 1977, when the original "Star Wars" premiered, and it won't happen again until 2034.
This time around, the moon will reach its peak size in the U.S. at 6:11 a.m. ET on Christmas morning.
"As we look at the moon on such an occasion, it's worth remembering that the moon is more than just a celestial neighbor," John Keller of NASA's Goddard Space Flight Center said in a statement.
"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."
Santa Claus will be riding his sleigh across the Full Cold Moon. It got that name because it's the first full moon of winter, which officially started on Dec. 21, the longest night of the year.