Posted on 12/31/2009 8:58:27 AM PST by Star Traveler
By Robert Roy Britt
Editorial Director
Posted: 31 December 2009, 08:38 am ET
Revelers can ring in the new year with a cosmic flourish tonight, celebrating the first New Year's Eve blue moon since 1990.
In truth, tonight's full moon won't be much different than any other full moon. In fact the term "blue moon" as it's used today originates from a writer's mistake.
"The 'blue moon' is a creature of folklore," says Philip Hiscock, a folklorist at the Memorial University of Newfoundland. "It's the second full moon in a calendar month."
If there's been a recent volcanic eruption that poured significant ash into the upper atmosphere, it is possible for the moon to take on a blue tint. That's not expected tonight.
All a big mistake
Hiscock helped figure out where the term came from. Long ago, "blue moon" was used to describe absurd things.
Then in 1946, amateur astronomer James Hugh Pruett (1886-1955), writing in Sky & Telescope magazine, "made an incorrect assumption about how the term had been used in the Maine Farmers' Almanac – which consistently used "blue moon" to mean to the third full moon in a season that contained four of them (rather than the usual three)," the magazine's editors explained this week.
Hiscock and Texas astronomer Donald W. Olson helped the magazine sort all this out and admit the blooper in 1999. The mistake led to the current definition of blue moon, generally accepted to mean the second full moon in a given month. The setup occurs about every 2.7 years.
Lunar lore
The blue moon mistake adds to a host of myths and mysteries about our moon. Among the more interesting things to ponder as you gaze up, weather permitting, at the not-really-blue blue moon:
There is no "dark side" of the moon. There is, however, a "far side" that we can't see, because the moon goes around the Earth once and spins on its axis once, all in the same amount of time, and it shows us just one face.
There's no solid evidence that the full moon affects behavior. Reliable studies comparing the lunar phases to births, heart attacks, deaths, suicides, violence, psychiatric hospital admissions and epileptic seizures have found little or no connection.
The moon is moving away. It's drifting into space as your read this, by about 1.6 inches (4 centimeters) per year.
The moon is never really full. It is lit by reflecting sunlight. So for the face of the moon to be 100 percent lit from our point of view, Earth would have to be exactly between the sun and the moon. But when that happens, there is an eclipse and the moon falls into total shadow.
Speaking of eclipses
Skywatchers in Europe, Africa, and Asia will have a chance to see a partial lunar eclipse tonight. A distinct but modest scallop of darkness will be seemingly carved from the moon.
Lunar eclipses can only occur at full moon, when our planet gets between the sun and the moon and can cast a shadow on the lunar surface. Because the moon's orbital plane is a few degrees off the plane of Earth's orbit around the sun, the three bodies don't usually line up exactly, so eclipses don't occur at each full moon, and not all eclipses are total.
The timing of the eclipse prevents it from being visible in the lower 48 United States. But compared to a partial lunar eclipse, a blue moon on New Year's Eve is, well, a "once in a blue moon" event.
In truth, tonight's full moon won't be much different than any other full moon. In fact the term "blue moon" as it's used today originates from a writer's mistake.
[ ... ]
Then in 1946, amateur astronomer James Hugh Pruett (1886-1955), writing in Sky & Telescope magazine, "made an incorrect assumption about how the term had been used in the Maine Farmers' Almanac – which consistently used "blue moon" to mean to the third full moon in a season that contained four of them (rather than the usual three)," the magazine's editors explained this week.
As simply as can be described, according to Trefethen's almanac, there are normally three full Moons for each season of the year. But when a particular season ends up containing four full Moons, then the third of that season is called a Blue Moon!
But, if you were to even use the mistaken impression of what a Blue Moon is -- it's going to be the second one in a month and not the first one... :-)
For more than half a century, whenever two full Moons appeared in a single month (which happens on average every 2 1/2 to 3 years), the second has been christened a "Blue Moon." In our lexicon, we describe an unusual event as happening "Once in a Blue Moon." This expression was first noted back in 1821 and refers to occurrences that are uncommon, though not truly rare.
On past occasions, usually after vast forest fires or major volcanic eruptions, the Moon has reportedly taken on a bluish or lavender hue. Soot and ash particles, propelled high into the Earth's atmosphere, can sometimes make the Moon appear bluish.
Why "Blue" Moon? For the longest time nobody knew exactly why the second full Moon of a calendar month was designated as a Blue Moon. One explanation connects it with the word "belewe" from the Old English, meaning, "to betray." Perhaps, then, the Moon was "belewe" because it betrayed the usual perception of one full Moon per month. However, in the March 1999 issue of Sky & Telescope magazine, author Phillip Hiscock revealed one somewhat confusing origin of this term. It seems that the modern custom of naming the second full Moon of a month "blue," came from an article published in the March 1946 Sky & Telescope magazine. The article was "Once in a Blue Moon," written by James Hugh Pruett. In this article, Pruett interpreted what he read in a publication known as the Maine Farmers' Almanac (no relation to this Farmers' Almanac, published in Lewiston, Maine), and declared that a second full Moon in a calendar month is a "Blue Moon."
However, after reviewing the Maine Farmer's Almanac, Hiscock found that during the editorship of Henry Porter Trefethen (1932 to 1957), the Maine Farmers' Almanac made occasional reference to a Blue Moon, but derived it from a completely different (and rather convoluted) seasonal rule. As simply as can be described, according to Trefethen's almanac, there are normally three full Moons for each season of the year. But when a particular season ends up containing four full Moons, then the third of that season is called a Blue Moon! To make matters more confusing, the beginning of the seasons listed in Trefethen's almanac were fixed. A fictitious or dynamical mean Sun produced four seasons of equal length with dates which differed slightly from more conventional calculations. So, basically the current use of "Blue Moon" to mean the second full Moon in a month can be traced to a 55-year-old mistake in Sky & Telescope magazine.
By Jay Michaels
Story Published: Dec 30, 2009 at 8:38 PM CST
When somebody says that something happens 'every once in a blue moon,' usually they mean it doesn't happen very often.
A local astronomer says that back in the 1940's, a researcher for 'Sky and Telescope Magazine' managed to misquote the definition of a blue moon as being a second full moon during a calendar month.
He says the Maine Farmer's Almanac defined the third full moon during a season – as a blue moon.
Faulkner Planetarium Manager Rick Greenawald says, “If there were four full moons during one of those seasons, the third full moon was referred to as the blue moon to keep the other moons in line with their traditional interpretation, harvest, hunters, and so forth.”
He says in seven out of 19 years, a total of 13 full moons will occur in a twelve month period; and he says by using the original method blue moons happen more often than the 'two full moons in a calendar month' reckoning.
For the year 2010, these are the dates of the moons in the northern hemisphere using UTC calculations. These dates use the actual solstices and not the artificial solstices that give each season an equal number of days.
A blue moon is a full moon that is not timed to the regular monthly pattern. Most years have twelve full moons which occur approximately monthly, but in addition to those twelve full lunar cycles, each solar calendar year contains an excess of roughly eleven days compared to the lunar year. The extra days accumulate, so that every two or three years (on average about every 2.7154 years[1]), there is an extra full moon. The extra moon is called a "blue moon." Different definitions place the "extra" moon at different times.
There is supposed to be some sort of lunar eclipse I thought.
It’s only a partial lunar eclipse and even that part of it is not in the U.S. ... :-)
First post on this thread I understand! Set me up, would you?
The science is settled, there is a consensus. Therefore, there will be a blue moon tonight.
Well..., the mistake about tonight not being the Blue Moon has been documented and admitted by the ones who made the mistake... LOL...
It seems you want to persist with the mistake... :-)
The science is settled, there is a consensus. Therefore, there will be a blue moon tonight.
I do understand what you're saying in regards to "Anthropogenic Global Warming" -- but this isn't quite in the same ballpark. It is a matter of "definition" and not so much about science, here, in regards to a Blue Moon.
However, what has become clear is that there was a mistake made a long while back, that was finally admitted to -- and it was a mistake in the long-held definition of a "Blue Moon".
So, here, we're correcting the mistake and reverting back to the original definition and not the mistaken definition.
It's not quite the same as "Anthropogenic Global Warming"... and "science"... :-)
This happened a few years back. I just happened to be flying back to SFO from FLL. I thought that weird.
I take that you think that I was being serious.
That might be true if the Blue Moon were defined as you say, however, that definition appears to be a mistake from a writer that started it from his mistaken understanding of the Farmer’s Almanac and their definition, and he “foisted” his wrong understanding on us... LOL...
No..., it was more like “I was being serious”... LOL.... (whether you were or not didn’t matter...) ... :-)
Actually it’s the “Anthropogenic Global Warming” which is the serious matter and not so much the “Blue Moon” (although it’s an interesting quirk in history that we “adapt” to other people’s mistaken impressions, as many have today).
So, no... it was more me... :-)
The excerpt is very confusing. So what is the correct definition of a “blue moon”?
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.