Why is a blue moon called so?

          Will a month have two full moons? Sounds almost impossible. Let’s take a look. The Moon takes almost twenty nine and a half days to change from one full moon to another. But, an average month has a span of thirty days. This makes it very unlikely for a month to have two full moons.

          However, some months do have two full moons and it happens very rarely. If there are two full moons in a month, the second full moon is called ‘blue moon.’ This name is not linked to the colour. In a century, there will be forty-one blue moons.

Picture Credit : Google