Today is the day for any unlikely event you care to see come
to pass because tonight will be a genuine blue moon. A blue moon is the second
full moon occurring in a calendar month, and that’s what you’ll get (weather
permitting) tonight. The origin of the term blue
moon is a little less clear. According to Wikipedia (oh dispenser of
undisputed truth):
“The suggestion has
been made that the term "blue moon" for "intercalary month"
arose by folk etymology, the "blue" replacing the
no-longer-understood belewe "to betray". The original meaning would
then have been "betrayer moon", referring to a full moon which would
"normally" (in non-intercalating years) be the full moon of spring,
while in intercalating year, it was "traitorous" in the sense that
people would have had to continue fasting for another month in accordance with
the season of Lent.”
This explanation seemed a little contrived for me, though. I mean a lot of the English language can trace its origin back to biblical references, but Lent is a once-a-year thing and to have a moon named after something that's rare at best doesn't sit well with me. Digging
into the Old Farmer’s Almanac confirmes the belewe reference, but also gives a second possible origin of the term:
“…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.”
Regardless of which origin you believe, the term blue moon
has influenced everything from beer to music to literature. It has a kind of
poetry, a wistfulness and quiet desperation that nests deep inside so much good
literature. A current favorite of mine is the poem The Blue Moon by James Francis Carlin MacDonnell.
The Blue Moon
Memory is as blue
As the small
flax-flower’s dew,
The twilight’s
distant skies
And your far eyes:
Blue as the meadows
seen
In reality as green;
Blue as the broad
moon-light
That is really white.
Memory is as blue
As the world that
relates to you,
From the heavens over
all,
To your blue shawl:
Blue as the roads
that may
Once more be dusty
grey,
For one whose sight
of mind
Is color-blind.
Memory as blue
As the winds that
sally through
The dark blue
shadows, deep
In your blue sleep:
Blue as your lips, to
be
That red reality,
Which I shall meet
when the light
Of the moon is white.
So, get out there under that old blue moon with the one you
love and make the most of this August night!