Very rare 'Super Blue Blood Moon' to appear on January 31
You've heard of supermoons, blue moons, and blood moons -- and depending on where you are on January 31st, you'll be able to see all three in one.
A supermoon occur when the full moon is closer to earth and brighter than normal.
A blood moon occurs when it takes on a reddish tint as it passes through earth's shadow in a lunar eclipse.
The blue moon designation has nothing to do with color, it simply refers to the very unusual occurrence of two full moons in a single month.