I use the phrase "once in a blue moon" without knowing what it really means. Shame on me. I just know that once in a blue moon is considered a rare event without proper reference and knowledge to blue moon. Well according to the news today posted in Philippine Daily Inquirer, we will have blue moons, not once, but twice this year.
Blue moon, according to its scientific definition, is the second full moon to occur in a month. Full moons to begin with are rare because it only happens every 29.5 days, technically once a month. Full moons happen when the sun, earth and the moon are formed in one straight line having earth in the middle. The blue term refers to the old saying of "hunters/harvest" moon. It does not have anything to do with color.
According to astronomical experts, blue moons (2 full moons per month) will happen twice for 2010. One blue moon for January (Jan 1 and Jan 30) and one blue moon in March (Mar 1 and Mar 30). The last blue moon the Philippines had was May 2007. But a blue moon that occurs in a new year only happens every 19 years.
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