No one knows exactly when the term blue moon originated. In literature and print it first showed up around 1600 A.D. in England during the time of William Shakespeare. At that time, it referred to a moon that literally looked blue.

I hope you didn't have a blue Christmas but you will have a blue New Year's whether you like it or not. The moon over Butler is seeing to that as we'll have a blue moon. You've no doubt heard the saying about "once in a blue moon," but to have a blue moon on New Year's Eve is really rare, the first time it's happened since 1971 and only the fourth time since 1900.

Don't be stepping outside clutching that bottle of bubbly expecting to see a blue hued moon, though, unless you've really been whooping it up! It'll look like any other full moon you've seen before.

Now, on very rare occasions, the moon can actually sport a bluish tint due to atmospheric conditions caused by forest fires or volcanic eruptions. Historically it's happened even recently.

The moon was blueish across many sections of eastern North America in September of 1950, due to smoke from widespread forest fires in western Canada.

Also, after the massive eruption of Mount Pinatubo in the Philippines in June 1991 there were many sightings of a physically blue moon all around the world. Fortunately these calamities don't happen all that often and that lends itself to the creation of the term once in a blue moon.

The astronomical definition of a blue moon has absolutely nothing to do with the moon having a tinge of the color blue nor does it mean that our lunar friend is sad.

It all has to do with mathematical odds. The synodic period of the moon, a five dollar astronomical term, is 29.5 days. That's the time it takes the moon to go through all its phase shape changes as it goes from evening crescent to full stage and back to morning crescent.

That being said then we have, a full moon every 29.5 days and since the average length of a calendar month is little over 30 days it's bound to happen that, we'll get two full moons in a month every now and then. In fact, on average, we have a blue moon about every 18 months. To experience a blue moon in any given month is a rarity for sure but to have one New Year's Eve is even more special.

No one really knows exactly when the term blue moon originated. In literature and print it first showed up around 1600 A.D. in England during the time of William Shakespeare. It wasn't defined as it is today as the second full moon in a calendar month but rather a visibly appearing blue moon, with a little imagination and possibly some added paranoia.

Many believed it was a bad omen of global calamities in the near future. Even back then the Y2K and 2012 Mayan end of the world buffs must have been in business. A blue moon's real or imagined appearance even interfered with the scheduling of church festivals and feast days.

A blue moon was also seen as a symbol of sadness and loneliness. Even music of the last century reflected this in songs like "Blue Moon" written in 1934 by Richard Rodgers and Lorenz Hart and recorded by tons of artists.

My favorite version of the song was recorded in 1961 by the Marcels, a doo-wop band that really added some kick to the old standby.

I want you to have a great and safe New Year's celebration this year. I sure hope it's clear enough for you to take some time to step outside in the blue moon moonlight. There won't be another New Year's blue moon until 2028.

Mars update

While you're out blue mooning New Year's Eve look for the planet Mars on the rise. It's the brightest starlike object you can see in the eastern sky and it has a definitely red tinge to it.

At midnight it'll be about half way from the overhead zenith near the moon to the eastern horizon. Mars and the Earth are drawing closer to each other and Mars is growing in size and brightness in eastern heavens.

Mars is now just under 68 million miles off. Mars and Earth will be at their closest celestial hugging, more formally known as opposition, this coming Jan. 29th when our Martian neighbor will be just under 62 million miles away.

I'll have more on our New Year's 2010 Martian encounter in the next several weeks.

Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and author of the book, "Pennsylvania Starwatch," available at bookstores and at his Web site www.lynchandthestars.com.