The world is watching a spectacular cosmic phenomenon on the evening of May 18, called the full blue moon. The moon completes this way, when the moon falls on the other side of the earth like the sun, which means its face is fully lit.
The moon does not appear in blue, where the name is used to indicate additional moon completeness in the two parts of the year. It is the third of four moons in this season, and usually there are only three moons in one season.
NASA explained that the blue moon is a special phenomenon, because it is the "extra" moon in one season with four full moons, which usually happens every two and a half years.
The next full blue moon was set for August 22, 2021.