2018 sees two blue moons in one year. Though this second one is not a supermoon, astronomy fans still get to enjoy an event that is even rarer than a blue moon. This year, there were blue moons in January, which was also a Supermoon, no full moon in February and another blue moon coming on March 31.
The saying, once in a blue moon, meaning, something that only happens rarely, seems a little false when blue moons seem to occur reasonably often, about once every two or three years. However, it turns out that there are two different definitions of a blue moon.
The modern definition is that a blue moon is the second full moon of a calendar month. But an astronomical blue moon is the third full moon of an astronomical month with 4 full moons. An astronomical season is from a solstice to a equinox or an equinox to a solstice, such as summer in Australia goes from the Summer Solstice in December to the Autumn Equinox in March.
Name and Colour
The origin of the term "Blue Moon" is shrouded in some mystery. The most common version of the story is that it from an old English word meaning betrayer moon. This is because, if two full moons occurred in the month before Easter, it meant that Lent was supposed to go on for another additional month. In other words, they were being betrayed by this moon and they had to keep fasting.
So the moon itself is unfortunately not blue, unless your location has some sort of atmospheric pollution. Of course, that doesn't stop you enjoying a full moon.
What to do on a Blue Moon
Full moons are always fun. Heading to the beach or a mountain to watch the moonrise is popular, as is full moon photography. Another option is enjoying the moonlight. While not as startlingly bright as a supermoon, enjoying the night away from city lights under a full moon is always a great experience.