When someone says it happens once in a blue moon, it is a common way of saying something does not happen very often. This will not happen again for the next three years, Lowvelder reported.
The phrase has nothing to do with the actual colour of the moon. Thought to be called “blue” after an old English term meaning “betrayer,” a blue moon is an extra full moon that occurs in that span, due to a quirk of the calendar.
By the Pruett definition, New Year’s Eve will fall on a blue moon in 2028, coinciding with a total lunar eclipse. The last New Year’s Eve blue moon happened in 2009.
In 1999, there were two full moons in both January and March, but no full moon at all in February. Full moons are supposed to occur once every month.
A lunar event more closely related to the literal colour of the moon came in early June this year when on the night of the 2nd and 3rd of June 2015 the full moon was a luminous orange.
The cause of the orange face was the planet Saturn and star Antares being in the eastern sky at dusk and nightfall on June 2. As Earth turned underneath the heavens, it looked towards the full moon. Saturn and Antares move westward across the night sky. The celestial threesome climbed highest up at about midnight and sat low in the west at dawn on June 3.
– Caxton News Service