'Blue Moon' to light up the skies on Oct 31

This Saturday is going to be ‘Once in a Blue Moon’. But no, the moon is not going to appear bluish on that day!

Dismissing the social media buzz with misinformation claiming October 31 as rare with the moon to be visible in blue, the Planetary Society, India- Hyderabad, says it’s just the second full moon in a single month. The first full moon of October was on October 2.

“In October 2020, moon will appear in its total phase (full moon) two times. First it was on October 2 and then the second full moon will be on October 31. This second full moon in a month is referred in western folklore as Blue Moon,” explains N.Sri Raghunandan Kumar, Director, Planetary Society, India-Hyderabad.

Generally in a calendar year, at least one full moon is visible in the sky every month. However, rarely i.e. once every two to three years or 2.715 years on an average, two full moons appear in the same



month. This, in western folklore is metaphorically used to describe the rarity of this occurrence and popularly referred to as Blue Moon. “The word Blue Moon is not coined or recognized by International Astronomical Union (IAU), the highest body responsible for astronomy,” the society said in a press release.

“It will be like any other full moon which people usually observe. However, social media is abuzz with misinformation on the Blue Moon claiming it as rare and that the moon will be visible in blue on October 31,” says Kumar.

When was the last time a Blue Moon event occurred and when is the next one? The last time the event occurred was in August 2012 and July 2015 whereas in 2018 it was double Blue Moons i.e. in January and March, people witnessed second full moon of the month twice that year. The next time the Blue Moon occurs will be in August 2023.