New Delhi | Jagran Trending Desk: The proverbial phrase- Once in a Blue Moon- is often used to signify rare occurrences. Well, October 31st is going to be that rare occasion when the sky will dazzle with a Blue Moon. When there are two full moons in a calendar month, the second full moon is called the Blue Moon. The usual monthly lunar phenomenon has one full moon and a new moon. However, two full moons in the same month is an unusual phenomenon. The occurrence of the first full moon took place around October 1 and October 2 while the second full moon is poised to end with a rare Halloween blue moon on October 31.

The last ‘blue moon’ in a month with 30 days was on June 30, 2007, and the next will be on September 30, 2050. In the year 1994, Blue Moon was spotted on Halloween day and now in 2020, it is going to be the same. Full moons are separated by 29 days, while most months are 30 or 31 days long; so it is possible to fit two full moons in a single month.

According to  Nehru Planetarium director Arvind Paranjpaye, the Duration of a lunar month is 29.531 days or 29 days, 12 hours, 44 minutes and 38 seconds. Therefore, to have two full moons in a month, the first full moon should take place on 1st or 2nd of the month. This extra time accumulates over the months. After about 30 months there will be one extra full moon in the year.

Interestingly, the appearance of the Blue Moon is seemingly not related to its color. Apparently, it happens due to the dust and smoke particles which should be wider than 900 nanometers and able to affect the scattering of red light in the atmosphere which somehow makes the moon appears blue.

Posted By: Rakesh Kumar Jha