Rare Blue Moon Inspires Beauty and Enlightenment

A plane flies in front of a full moon in Arlington, Va., on July 31, 2015. NASA/Joel Kowsky

A rare lunar event will be visible until May 20 and celebrated by different cultures for its mystical meanings.

A blue moon appeared across the evening sky on May 18 and will continue to be seen for two more nights, making this a full moon weekend. Native American tribes in northeast United States call the rare spectacle the flower moon, corn planting moon, and even the milk moon.

The National Aeronautics and Space Administration (NASA) said this is because flowers are abundant this time of year in most of these areas, according to the Maine Farmer’s Almanac.

“Some writers tie these Native American names to the months of our modern calendar but I think it more likely these names were tied to the seasons,” NASA Solar System Exploration Program Executive Gordon Johnston said in written statement. “For the past year, the full moon names by season and by month have been out of sync but this spring’s ‘extra’ moon brings them back into sync again.”

According to Buddhist cultures in many parts of Asia, the blue moon corresponds to Vesak, also known as Buddha Purnima. A holiday is traditionally observed by Buddhists in Nepal, Sri Lanka, Tibet, Bangladesh, Bhutan, India, and the South East Asian countries of Singapore, Vietnam, Thailand, Cambodia, Laos, Malaysia, Myanmar, the Philippines, and Indonesia.

“Sometimes informally called ‘Buddha’s Birthday,’ it actually commemorates the birth, enlightenment (nirvāna), and death (Parinirvāna) of Gautama Buddha,” Johnston said. “The actual date of Vesak varies depending upon the lunar calendar in use in the particular country or region but this year for most areas it falls on or near the day of this full moon.”

There is also an old English saying called “once in a blue moon,” meaning something that rarely happens once after a long period of time.

“Speculations on the origin of the term include an old English phrase that means ‘betrayer moon’ or a reference to rare events, such as when dust in the atmosphere makes the moon actually appear blue,” Johnston said. “Since the 1940s, the term ‘blue moon’ has also been used for the second full moon in a month that has two full moons.”

In lunisolar calendars, the months change, with the new moon and full moons falling in the middle of the lunar months. This full moon is the middle of the fourth month of the Chinese calendar and Iyar in the Hebrew calendar.

“As the third full moon in a season that has four full moons, this will be a blue moon by the older definition. The moon will not actually appear blue in color,” Johnston said.