Blue Moon

Q. Once in a blue moon

A. The phrase means 'very rarely', and it is derives from those extremely rare occasions that the moon actually does appear to be blue.

�

Q. What makes the moon blue

A. The cause is minute dust particles in the upper atmosphere, usually as a result of smoke or ash after a volcanic eruption. These block the light from the red end of the spectrum and scatter light from the blue end, with the result that the reflected sunlight from the moon shines through as blue - and sometimes green or turquoise - to observers on earth.

�

Q. Any examples

A. After the famous eruption of Krakatoa, Indonesia, in 1883, countries as far from the explosion as Turkey had frequent blue moons for more than a month after the event. Blue moons were also seen after the eruption of Mount St Helens in the US in 1980. Very, very occasionally, there are reports of blue moons corresponding with no known volcanic activity, which continue to challenge scientific insight.

�

Q. Is there a less scientific explanation as to the origin of the phrase

A. There are usually 12 full moons in a year and full moons have been named for activities or festivals at that time of the year. Occasionally - seven times every 19 years - there are 13 full moons in a year, traditionally this has been known as a blue moon.

�

Q. And Blue Moon of Kentucky

A. Recorded at the Sun Studios in Memphis and released on 19 July 1954, Blue Moon of Kentucky, along with a version of Arthur Crudup's That's Alright Mama, was Elvis Presley's first commercial single. A rockabilly reworking of Bill Munroe's bluegrass tune, Blue Moon of Kentucky is arguably the most important record in the history of white popular music, fusing as it does the various strands of southern US folk music, both black and white - hillbilly, bluegrass and blues - and putting Memphis and its most famous son on the international music map for ever.

�

For more on Phrases & Sayings click here

�

By Simon Smith