This August, we will have two full moons! The second full moon that occurs in the same month is called “Blue Moon”, and this time, it falls on the last night of summer.
A blue moon is a second full moon that takes place within one month. This year, it will happen in August: the first fool moon will be on August, 2 and the second and a more “rare” one – on August, 31.
It is not a very common phenomenon when two full moons are observed within one month, especially when it comes to the August moon.
Why is it called a ‘blue moon’?
The second full moon in the month is called “blue” not only because it is rare and unusual but because once, it really used to be blue. And not for just one night, but for years.
In 1883, the great eruption of the Krakatoa volcano occurred in Indonesia. Being 600 km away, people heard the explosion as a cannon shot. The explosion was comparable to the effect of a 100 megaton bomb.
Dust and ashes ejected in the upper layers of the atmosphere. Then the refraction of moonlight in the smog particles from volcanic eruptions gave the moon a blue color.
It is believed to have paved the way for the famous phrase “once in a blue moon“. The consequences of the eruption were so weird and rare that since then, people started using this expression to define something that happens extremely rarely.
Astronomers, in turn, adopted the phrase “blue moon” to describe the occurrence of two full moons within one month. However, the second full moon in one month is not such a rare phenomenon. In reality, it takes place every 2,5-3 years.
In any case, if the weather is not too rainy or cloudy, take a moment to look up at the night sky on August 31!
