2009
Goes Out With Blue Moon
A Blue Moon is the second full moon in a
calendar months. For a blue moon to occur,
the first of the full moons must appear at
or near the beginning of the month so that
the second will fall within the same month
(the average span between two moons is 29.5
days).
Most people are familiar with the term "Once
in a blue moon", meaning "very
infrequently".
Variations on this phrase have been in use
for some 400 years, and certainly a visibly
blue moon is a rare event. They can be
caused by smoke or dust particles in the
atmosphere, such as happened after forest
fires in Sweden in 1950 and Canada in 1951
and, notably, after the eruption of Krakatoa
in 1883 which caused blue moons for nearly
two years.
However, the best known physical definition
is the one which states that the second full
moon in a month is called a blue moon.
This happens about seven times every 19
years, though the dates vary around the
world because, even though a full moon
occurs at the same moment for the whole
planet, there are many variations on local
time. In 1999, for instance, there were no
fewer than four different scenarios
depending on your location and variations in
daylight saving time.
The last blue moon was in May 2008 and the
last to appear on New Year's Eve was in
1990, the next to occur in 2028.
|
|
|
 |
|
| |
|
|
|
|
|
|
