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| NASA Picture of the Day |
Did you see last night’s glorious blue moon? And if so, did
you see it shining behind the scaffolded Capitol dome? No matter – you can see
it now:
If you are thinking, this is something you don’t see very
often, then you are using the phrase “blue moon” exactly right. While many
people think “once in a blue moon” means something that virtually never occurs,
a careful and correct use of the term is reserved for something that occurs
only occasionally, perhaps every couple of years. A full moon is called a “blue
moon” by almanac and calendar makers* when it is the second full moon within
the same calendar month. And it’s something we all have a chance to see
multiple times over the course of our lives, as the interval between blue moons
is seldom longer than three years.
We can expect the next blue moon on Saturday, May 21, 2016.
But the next two after that, in 2018, will be really something special, as 2018 is a double blue moon
year – a true rarity. The last time there was a double blue moon year was 1999.
For the next double blue moon year after 2018 you’ll need to wait patiently until 2037. (More info on this at http://bit.ly/1eL5x8H.)
As you can see from these photos - http://bit.ly/1IwfSNw - there’s nothing about a blue moon that’s actually blue. But there is another
type of blue moon that has nothing to do with the calendar; it’s literally
blue. That happens only when there’s been a volcanic eruption or some other accumulation
in the night sky of the right kind of ash or particulate matter to catch and reflect
a bluish glow onto the moon. And it’s something we will never see here in
Washington, DC, no matter how many years we wait. Chalk it up to our lack of
volcanoes.
If all this talk of blue moons has got the song “Blue Moon”
running through your head, then let Sinatra sing it for you while you watch this charming
compilation of images of last night’s blue moon from around the world, courtesy
of the BBC: http://www.bbc.com/news/world-33745560
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* I realize I need to footnote an older, now somewhat
abandoned understanding of the term “blue moon.” The original almanac maker who
coined the term intended it to describe an “extra” full moon during a three-month
season. Normally, there are three full moons in a season, but if there happen
to be four full moons in a season, traditionally, farmers would call the third
of the four full moons a “blue moon” (Aren’t you glad you now can distinguish
between these two different definitions? Not that it will ever be of any use to
you to know this…. But if you are the type to enjoy knowing this sort of
trivia, then you will want to watch all of NASA’s five-minute primer on the subject: http://1.usa.gov/1gyLJXX.
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Still Life With Robin is published on the Cleveland ParkListserv and on All Life Is Local on Saturdays.
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