“Once in a Blue Moon,” one says when something rare happens. Today is one of those days.
Sky gazers are in for a treat tonight (October 31) as the evening sky will host the Blue Moon. If the sky is clear with less pollution, it will be visible and would give viewers a great view. This night the Blue Moon will appear close to Mars, adding to the spectacle. This Blue Moon coincides with Halloween (a famous festival celebrated worldwide, lighting bonfires, wearing costumes to ward off ghosts). You need to wait till 2039 for a Blue Moon day on Halloween, it is truly once in a Blue Moon this year! It is also the Northern Hemisphere’s Harvest Moon (full moon nearest the September equinox).
The Blue Moon is a phenomenon where two full Moons appear in the same month. When this happens, the second moon to appear that month will be called the Blue Moon. The name “Blue Moon” is being used for two different moons: the second of two full moons in a calendar month, or third of four full moons in a single season (winter, spring, summer, fall). Generally, this happens when there are 31 days in a month. 12 full Moons in a year and the thirteenth full moon would be a Blue Moon and occurs once in every two to three years. According to the old Maine Farmer’s Almanac, if a season has four full moons, then the thirdfull moon may be called a Blue Moon. Not so common that a seasonal Blue Moon and a monthly Blue Moon occur in the same calendar year. Next time it would happen in the year 2048 and then in 2067.
The idea of a Blue Moon as the second full moon in a month can be traced back to an article “Once in a Blue Moon” by James Hugh Pruett in March 1946 issue of Sky and Telescope magazine. ‘Old folklore’ it is not, but real folklore it is. Philip Hiscock’s article titled “Where Does the Phrase “Once in a Blue Moon” Come From?” (appeared in August 24,2012 of “Sky &Telescope The Essential Guide to Astronomy”) is an excellent read. It summarises the inquiry into where this usage of Blue Moon originated.
The moon always evoked romantic emotions. Poets emoted “Blue Moon” as a symbol of sadness and loneliness. It turns to gold when the lover gets his love at the end of the song. The famous song of the sixties by Elvis Presley
You saw me standing alone Without a dream in my heart Without a love of my own...
Calling It “Blue Moon” is symbolic, the moon would not look blue.
A search of web brings out the historical occurrences of the moon turning blue. When the Indonesian volcano Krakatoa exploded in 1883, its dust turned sunsets green and the Moon blue. Late arrival of monsoon in India, in 1927, the extra-long dry season blew up enough dust for a blue Moon. In 1951 when massive forest fires in western Canada threw smoke particles up into the sky and turning moon blue.
Hopefully, we would never see a real, blue-coloured moon in the sky. It would happen when Earth’s atmosphere contains dust or smoke particles slightly more expansive than 900 nanometres. The way the pollution goes up every year at this time of the year in Delhi and surrounding areas hope it does not end up making the moon blue.
Restrictions imposed by the COVID pandemic would not permit you to venture to go to the seashore to enjoy the emerging of the Blue Moon. If you have access to the terrace, do not forget to go up and watch the spectacle of Blue Moon and the red planet in its proximity.