Blue Moon 2013, Rare Lunar Event This Week

Stargazers everywhere are celebrating this month's full moon, as it is known as a rare Blue Moon.

Visible on Tuesday night and into Wednesday, the full moon marks the third full moon seen this quarter of the year.

There are varying definitions for the term blue moon, with one indicating the second of two full moons within any given month, while another refers to a Blue Moon as the third full moon in a season with four-full-moon season.

 Nevertheless, a blue moon is a rare occurrence; hence the phrase "once in a blue moon."

This week's full moon qualifies as a Blue Moon because it marks the third full moon of the season and aligns with the lesser-known definition aforementioned.

Moreover, the annual August full moon is also known as the Full Sturgeon Moon because the fisherman can easily catch sturgeon during this time of year, according to The Huffington Post.

Other nicknames for this month's full moon include the Full Red Moon, which refers to the occasional red glow. It is also called the Green Corn Moon or Grain Moon due to corn crops thriving during this time of year.

Blue moons exist due to our calendar months being imperfectly synched to the lunar months. It takes 29.5 days for the moon to orbit Earth, during which sky watchers observe all of its phases. All calendar months, aside from February, have 30 or 31 days, resulting in the occasional two full moons within a single month.

The name of the event comes from the colors the moon takes on from time to time due to different conditions. After volcanic activity or forest fires, the moon can appear to take on a bluish or sometimes lavender coloration. This is because of soot and ash particles deposited high up into the Earth's atmosphere.

Furthermore, smoke from a large wildfire created a blue moon across eastern North America in late September 1950, according to CBS News.

While blue moons are rare, they can be predicted to occur every three years or so. The next blue moon is slated for 2015, according to USA Today.