While pondering on the last topic of an orange coloured moon, TPP remembered the saying “once in a blue moon”.
Now most of you will have heard of this saying, but how many of you actually know what it means?
For those of you who don’t know – the short answer is the saying relates to something that happens very rarely.
And the long answer – it comes from commonly used in astrology. It is when there is a second full moon within a calendar month. A lunar month lasts 29.5 days and a calendar month can vary from 28 to 31 days, so you generally get one full moon every month. But, because of the slightly different length between a lunar month and a calendar month the timing of when a full moon appears changes a little each month. Over time the differing lengths mean you get two full moons in the same month.
So how often does a lunar blue moon actually occur, I hear you ask. Well from the experts at the Royal Museums Greenwich…
“Normally blue moons occur about every two or three years. In 2018, unusually, we had two blue moons in one year and only two months apart – and one was a lunar eclipse! The next time we will get two blue moons in a year will be 2037.”
Royal Museums Greenwich
To find out more about blue moons check out the page at the Royal Museums Greenwich or at Sky & Telescope.
So your homework today is to ponder on what are the things that you only do “once in a blue moon”, why you do them so rarely and should you do those things more regularly or not.
Ponder away!
