What is a Blue Moon and When Will the Next One Occur?Have you ever heard of a blue moon? Discover the history and folklore behind this rare lunar phenomenon in this informative article.
A Blue Moon is a rare event, hence the expression "once in a blue moon". The phrase has nothing to do with the actual colour of the moon. A blue moon is an event that occurs when there are two full moons in a single calendar month. While the term "blue moon" has been around for centuries, it wasn't until the 1940s that it became associated with this particular lunar phenomenon.
There are times when the moon can appear with a tinge of blue when certain atmospheric conditions, such as when there are volcanic eruptions or when exceptionally large fires leave particles in the atmosphere. This is not what we call a blue moon.
A blue moon has traditionally come to mean an additional full moon that appears in a given calendar month. This is a fallacy originating from the March 1946 issue of Sky & Telescope which misinterpreted the traditional definition.
The Origins of the Term "Blue Moon"
The origins of the term "blue moon" are somewhat unclear, but it is believed to have originated in folklore. In early English folklore, the term "blue moon" was used to describe a rare event, much like the phrase "once in a blue moon" is used today. It wasn't until the 16th century that the term began to be associated with the moon itself. The term "blue moon" was often used to describe a moon that appeared to be blue in colour, although this is a rare occurrence that is caused by atmospheric conditions rather than the actual colour of the moon.
Folklore and Superstitions Surrounding Blue Moons
Throughout history, blue moons have been associated with a variety of folklore and superstitions. In some cultures, it was believed that a blue moon was a sign of impending disaster or a time of great change. Others believed that a blue moon was a time of heightened spiritual energy and that it was a good time for meditation and reflection. In some Native American cultures, the second full moon of the year was known as the "blue corn moon" and was a time for planting and harvesting crops. Despite the many different beliefs surrounding blue moons, one thing is certain: they continue to capture our imagination and inspire us to look up at the night sky in wonder.
The Science Behind Blue Moons
Despite its name, a blue moon isn't actually blue. The term "blue moon" refers to the second full moon that occurs within a calendar month. This phenomenon happens because the lunar cycle is approximately 29.53 days and there are about 365.24 days in a tropical year.
There are about 12.37 lunations (365.24 days divided by 29.53 days) in a tropical year. Normally there is one full moon each month, and each calendar year contains roughly 11 days more than the number of days in 12 lunar cycles. These extra days accumulate, so every two or three years, there is an extra full moon. The extra moon falls in one of the four seasons, giving that season four full moons instead of the usual three, and hence a blue moon.
As you can see from the table below, the event is quite rare! An average year contains 12 full moons, and these years feature 13 full moons.
Blue Moon Calendar - When Is The Next Blue Moon
You can use this table to see when the next blue moon occurs.
| Year | First Full Moon of month | Second Full Moon of month |
|---|---|---|
| 2012 | August 2, 2012 | August 31, 2012 |
| 2015 | July 2, 2015 | July 31, 2015 |
| 2018 | January 2, 2018 | January 31, 2018 |
| 2018 | March 2, 2018 | March 31, 2018 |
| 2020 | October 1, 2020 | October 31, 2020 |
| 2023 | August 1, 2023 | August 31, 2023 |
| 2026 | May 1, 2026 | May 31, 2026 |
| 2028 | December 2, 2028 | December 31, 2028 |
| 2031 | September 1, 2031 | September 30, 2031 |
| 2034 | July 1, 2034 | July 31, 2034 |
| 2037 | January 2, 2037 | January 31, 2037 |
| 2037 | March 2, 2037 | March 31, 2037 |
| 2039 | October 2, 2039 | October 31, 2039 |
| 2042 | August 1, 2042 | August 31, 2042 |
How to Observe a Blue Moon
Observing a blue moon is no different than observing any other full moon. Find a clear, dark location away from city lights and look up at the sky. The moon will appear bright and full, with no blue tint. However, if you want to add a bit of magic to your blue moon viewing experience, try incorporating some of the folklore associated with this rare event. Some people believe that blue moons are a time of heightened spiritual energy, and use the occasion to set intentions or perform rituals. Others simply enjoy the novelty of seeing two full moons in a single month. Whatever your approach, a blue moon is a special and rare event that is worth taking the time to appreciate.
While blue moons may not be scientifically significant, they continue to capture our fascination and inspire us to learn more about the mysteries of the universe.
