ONCE in a blue moon there is one on New Year’s Eve.
Revelers ringing in 2010 were treated to a blue moon at 7 p.m. universal time (3.10 a.m. Friday in the Philippines).
A blue moon is defined as the second full moon to occur in a month. A full moon occurred on Dec. 2. It appeared again last night in time for the New Year’s countdown in the United States, Canada, Europe, South America and Africa.
But since the Philippines is eight hours ahead of universal time (previously known as Greenwich mean time, or GMT), the blue moon here lapsed into Jan. 1 at 3:12 a.m.
Strictly speaking, it was not a blue moon for the Philippines, according to astronomer Frederick Gabriana, an instructor at the Rizal Technological University’s astronomy department.
But the country will still experience two blue moons this year, making 2010 a rare lunar year for the Philippines.
The relative rarity of this phenomenon is the reason why the idiomatic expression “once in a blue moon” is used to describe the rarity of an event.
We will have a blue moon in January, no full moon in February and another blue moon in March, Gabriana said.
The country will experience two full moons for the month of January, with the first on Jan. 1 and the second on Jan. 30, making the latter the blue moon.
In February, there will be no full moon because the month will have 28 days. A full moon occurs every 29.5 days, and most years have 12.
But March will again have two full moons, the first on March 1 and the second, considered the blue moon, on March 30.
“Altogether, these events happening in the same year are very rare. This makes 2010 a rare lunar year in astronomical terms for the Philippines,” said Gabriana.
A full moon is defined as the alignment of the sun, moon and earth in a straight line with the earth in between the two heavenly bodies.
The last time there were two full moons in a month (universal time) was in May 2007. A blue moon on New Year’s Eve universal time is more rare and happens every 19 years. The last time this happened was in 1990. The next New Year’s Eve blue moon is set to occur in 2028.
Usually, a blue moon in January would mean a double blue moon for the year. Hence, double blue moons in universal time occur approximately every 19 years.
The last blue moon in the Philippines occurred on June 30, 2007.
In addition to the full moon on Jan. 1, the Eastern Hemisphere experienced a partial lunar eclipse when part of the moon entered the Earth’s shadow, said Gabriana.
First contact, or the first time the shadow of the earth touched the moon’s surface, occurred at 2:51 a.m., Jan 1. The maximum point of the partial eclipse occurred on 3:22 a.m. and the last contact was at 3:53 a.m.
The eclipse was not visible in the Americas.
No significance
Blue moons have no astronomical significance, said Greg Laughlin, an astronomer at the University of California, Santa Cruz.
“‘Blue moon’ is just a name in the same sense as a ‘hunter’s moon’ or a ‘harvest moon,’” Laughlin said in an e-mail.
The term has nothing to do with the color blue. The moon does not turn blue.
The popular definition of blue moon came about after a writer for Sky & Telescope magazine in 1946 misinterpreted the Maine Farmer’s Almanac and labeled a blue moon as the second full moon in a month. In fact, the almanac defined a blue moon as the third full moon in a season with four full moons, not the usual three.
Though Sky & Telescope corrected the error decades later, the definition caught on. For purists, however, this New Year’s Eve full moon doesn’t even qualify as a blue moon. It’s just the first full moon of the winter season.
In a tongue-in-cheek essay posted on the magazine’s Web site this week, senior contributing editor Kelly Beatty wrote: “If skies are clear when I’m out celebrating, I’ll take a peek at that brilliant orb as it rises over the Boston skyline to see if it’s an icy shade of blue. Or maybe I’ll just howl.”
Mayon’s activities
But there have been instances when the moon actually seemed to turn blue. When Mount St. Helens erupted in 1980, the tons of ash it sent into the atmosphere gave the moon a bluish tinge.
A “true” blue moon also appeared in 1950 after a large forest fire in Canada.
Can the current activities of Mayon Volcano turn the moon blue?
An article posted at www.nationalgeographic.com on Dec. 30 said: “Although rumblings at the Mayon Volcano in the Philippines seem to signal a major eruption is imminent, experts don’t think Mayon’s current output will make this New Year’s Eve full moon turn blue.”
| < Prev | Next > |
|---|
