"Once in a blue moon" refers to something that is rare, and today is your chance to witness it. A blue moon will appear today for your viewing please. Many people are confused with the terminology because it doesn't actual mean the moon is blue. It just means that there is a second full moon in one calendar month which doesn't occur very often.
In Los Angeles, you have two chances to the the blue moon on Friday. Once in the morning as the blue moon is setting for the day, according to Anthony Cook an astronomical observer at Griffith Observatory. He says to look for the early-morning blue moon between 6:30 a.m. and 7 a.m. PDT.
Then later in the day when the blue moon rises again at 7:13 PDT.
Cook said that the moon will most likely appear a brilliant white, not blue like it's moniker.
It's unclear why the term came to pass. It could be because the moon has looked blue on certain occasions and it is scientifically possible, though rare. Atmospheric conditions such as after forest fires or volcanic eruptions can cause the moon to appear bluish and ash particles that are deposited into the earth's atmosphere can make the moon appear bluish or a lavender hue.
A blue moon occurs because the average lunar cycle is 28 to 29 days long so most months you only see one single full moon.
Cook said to The Christian Science Monitor, "As a result, the lunar cycle gets out of phase with the calendar," Cook said. "If you have a full moon right at the beginning of the month, you can get one at the end of the month."
A blue moon has not occurred since December 2009 and will not reappear again until July 31, 2015.
See here for more info about blue moons.
Watch it online
For real fans, if you want to watch the blue moon online, check out Slooh.com which shows live video taken from telescopes around the globe.
Slooh has a broadcast that starts at 3 p.m. Pacific time on Friday and will have live feeds of the moon from an observatory located in the Canary Islands.
Check out this NASA video for more info about blue moons:
This article is copyrighted by Travelers Today, the travel news leader
