On May 18, a Blue Moon will rise, treating Earth to a spectacular lunar display. Despite the name, a Blue Moon is actually white but usually earns the name because it is a lunar cycle which involves two full moons in a month. However, in this instance, it has been given the name Blue Moon as it is the third of four full moons in a single season.
May’s full Moon has several names, all of which connect it to the fact that it signifies Spring, which are “flower loon”, “corn planting moon” or “milk moon”.
NASA even states on its website that the term Blue Moon has volcanic roots.
The space agency says: “The term Blue Moon is believed to have originated in 1883 after the eruption of Krakatoa. The volcano put so much dust in the atmosphere that the Moon actually looked blue in colour.
“This was so unusual that the term ‘once in a Blue Moon’ was coined. However, Blue Moon was also used in much the same way we use the term ‘Harvest Moon’.
“There were twelve names for full moons, one for each month, and the name Blue Moon was used in years which had 13 full moons. It referred to the third full moon of the four occuring between an equinox and solstice in that year.
The Blue Moon should not be confused with a Super Moon, which is when our lunar satellite is closer than average.
On average, the moon is 238,000 miles from Earth, but during a Super Moon the can be 221,000 miles away from our planet.
This is because the Moon’s orbit is not a perfect circle and is actually slightly oval.
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