On March 31 the night sky saw a rare phenomenon: if you found yourself outside you most likely stood in the light of a blue moon. Rarer still, is that it was the second blue moon of this year, the other having been on Jan. 31.

It cycles through a variety of appearances such as a crescent moon (less than half illuminated), half-moon and a gibbous moon (more than halfway illuminated). These phases are dependent on its location in respect to the sun and Earth.

Since then, the moon reflects the sun’s light a crescent moon occurs when the moon is closer to the sun in its rotation around the Earth; a gibbous moon is further from the sun in its rotation. Therefore, a new moon (no moon) is when the moon is at its closest because it reflects all the sun’s light back to the sun because the Earth lies behind the moon. A full moon is when the moon is at its furthest from the sun during its rotation. Since the moon’s rotational disk is at a slight angle, the Earth does not normally cause an eclipse on the moon. The moon then reflects all of the sun’s light down onto the Earth, thus resulting in a full moon.

Tales and folklore of the full moon giving rise to werewolves haunt the thoughts of children and even adults throughout history. 21st century reasoning extinguished the threat of werewolves from people’s minds, but it’s also affected real phenomena. The legend of the blue moon is almost seen as a myth these days.

This is mainly due to the saying “once in a blue moon,” meaning that an occurrence happens very rarely. Blue moons themselves have become so rare that some people believe it is not a real occurrence.

There are two definitions of a blue moon: one is the second full moon in a calendar month, and the other is that they are the third full moon of a season that has four full moons. The first definition is what we use today as our definition of a blue moon, the other is an older term which has lost its meaning throughout the years.

It is believed the blue moon got its name due to a volcanic eruption. Dust and debris littered the atmosphere after the eruption and filtered out some of the moon’s light causing it to appear blue for a certain period of time.

In case you missed the recent blue moon, have no fear. The next one is scheduled to occur on May 18, 2019. Don’t forget to mark your calendars now so you don’t miss this once in a blue moon opportunity.