Once in a blue moon, you get to witness two full moons in a month. Don’t forget to take look at the night sky on Friday as the proverbial ‘blue moon’ will occur a couple of minutes before 7.30 pm in India. If you miss this opportunity, you will have to wait for a little more than two years to see it. The moon, however, will not appear blue. It will look just like any other full moon, yet beautiful. Since the lunar year is 11 days short of the solar calendar, it happens once in every few years that the full moon occurs twice in a month.
“For the second time this month, there will be a full moon. While there was one full moon on August 2 (in India), there will be another one on August 31. According to modern folklore, whenever there are two full moons in a calendar month, the second one is called ‘blue’,” said the National Aeronautical and Space Administration in a press statement. According to N. Sri Raghunandan Kumar of Planetary Society of India, one can look eastward on August 31 to see the moon, which will rise at 6.13 pm. It will technically attain the full or total phase at 7.28 pm. “The next time this will happen would be on July 31 in 2015 (July 2, 2015 and July 31, 2015).”
Although the moon does not look blue on a blue moon day, it does take on a blue hue when there is a major volcanic eruption on Earth. “A truly-blue moon usually requires a volcanic eruption. Back in 1883, for example, people saw blue moons almost every night after the Indonesian volcano Krakatau exploded with the force of a 100-megaton nuclear bomb. Plumes of ash rose to the very top of the Earth’s atmosphere, and the moon… it turned blue!” the Nasa release said.
People also saw blue-coloured moons in 1983 after the eruption of the El Chi Chon volcano in Mexico. And there are reports of blue moons caused by Mt. St. Helena in 1980 and Mount Pinatubo in 1991. Certain forest fires can do the same trick. A famous example is the giant muskeg fire of September 1953 in Alberta, Canada. Clouds of smoke containing micron-sized oil droplets produced lavender suns and blue moons all the way from North America to England, the release added.