All the astronomy enthusiasts should get ready again for a "once-in-a-blue moon" event. This real Blue Moon astronomic event, as scientists explain, won't happen again for quite a while.
The term "blue moon" describes, in most cases, an astronomic phenomenon that takes place when two full moons happen in the same calendar month. This rare event will occur again on July 31, according to Earth Sky.
In a normal month, the moon is only full once every 30 days. The blue moon phenomenon can occur only if there is another full moon in the first few days of a month. For this month, July 2015, we experienced the last full moon on the date of July 2.
A Blue Moon phenomenon can occur once every two or three years. According to astronomers, the last Blue Moon phenomenon took place on Aug 31, 2012 and there won't be another after this month until 2018.
Throughout time, the term blue moon has developed quite a few definitions. According to reports, the Maine Farmer's Almanac defines the blue moon in a different way, as the third full moon out of four, occurring in a season. If we take into consideration the fact that there are usually three full moons in each of the seasons, whether summer, spring, winter or fall, then according to Farmer's Almanac a blue moon would describe the third moon in a rare season that has four.
Even if the modern definition is relatively new and the concept of a seasonal Blue Moon has been around longer, the argument as to which definition is more accurate continues. However, either way, it's far less likely to actually see a moon that is blue in color. Among other factors, these are based on sky conditions, and they are entirely unpredictable. According to NASA, when Indonesia's Krakatoa volcano erupted in the year 1883, for years to follow the massive ash clouds led to blue colored moons.
Besides the blue moon phenomenon, another is one of interest for astronomers and sky-gazers alike is the one called the super-moon. A super-moon or a perigee moon is referring to the closest point our natural satellite gets to Earth. It is called super-moon because the its surface appears brightener and bigger than normal.
