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Sunday, November 21, 2010

Blue Moon Blues

Several news outlets have been reporting tonight's full moon as a "blue moon", which of course seems ludicrous since it's only the third week of the month. However, this is apparently based on a now defunct definition of a blue moon, being the third full moon in a season which has four full moons. 

So the media was able to glean this bit of trivia from gods only know where, but failed to understand that a 100-year starship and a one-way ticket to Mars were two different projects.

The mind reels.

From Joe Rao at

The full moon of November arrives on Sunday and will bring with it a cosmic addition: It will also be a so-called "blue moon."
"But wait a minute," you might ask. "Isn't a 'blue moon' defined as the second full moon that occurs during a calendar month? Sunday's full moon falls on Nov. 21 and it will be the only full moon in November 2010. So how can it be a 'blue' moon?"
Indeed, November's full moon is a blue moon – but only if we follow a rule that's now somewhat obscure. 

                                          Photo (c) Laura Treadway

In fact, the current "two- full moons in one month" rule has superseded an older rule that would allow us to call Sunday's moon "blue." To be clear, the moon does not actually appear a blue color during a blue moon, it has to do with lunar mechanics.
Confused yet? 
Well, as the late Paul Harvey used to say — here now, is the rest of the story 

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