The second full moon in a month is called a “blue moon.” We tell you what this phenomenon is and when it can be observed

Content:

What is a “blue moon”
When will it be in 2024
Does the “blue moon” affect a person?

What is a “blue moon”

A Blue Moon is an astronomical phenomenon in which two full moons can be observed in one calendar month. The term comes from the English idiom once in a Blue Moon – “very rarely” [1] .

What does a “blue moon” look like?

The name of the phenomenon has nothing to do with the change in color of the Earth’s satellite. Most often, a “blue moon” looks like a regular full moon. But sometimes you can observe an optical illusion: small particles of smoke or ash in the air scatter red waves, and then the Moon acquires a blue tint. Smoke from forest fires can scatter light. A blue moon appeared for several years after the eruption of the Krakatoa volcano in 1883. Then a huge amount of ash rose into the atmosphere to a height of 80 km [2] .

Why does a “blue moon” appear?

One lunar cycle—the period from new moon to full moon—lasts 29.5 days. Therefore, 12 lunar months pass in 354 days – less than in a calendar year. As a result of this discrepancy, an additional full moon appears every 2.5–3 years.

It is customary to distinguish between a seasonal and calendar “blue moon”. In winter, spring, summer and autumn we usually see three full moons. If the fourth appears, it is a “blue moon”. And the second full moon in a month is the calendar “blue moon”  [3] .When

is the blue moon in 2024?

• The Blue Moon is expected on August 19, 2024 at 21:25 Moscow time. This will be a seasonal phenomenon. You can check the dates of full moons and find out the exact time of their appearance in your region in the Sky Tonight app or online [4] .Next time you will be able to see the seasonal “blue moon”:
• May 20, 2027 at 1:59 p.m.;
• August 24, 2029 at 04:51;
• August 21, 2032 at 04:46.

The calendar “blue moon” is expected:

• May 31, 2026 at 11:45 am;
• December 31, 2028 at 19:48;
• September 30, 2031 at 9:58 p.m.

Does the “blue moon” affect a person?

Folk signs associate the full moon, including the “blue moon,” with a negative effect on the body. It is believed that during this period insomnia appears, and the number of calls from doctors increases sharply. However, numerous studies show that the full moon does not affect humans in any way [5] .

In 2021, a study was conducted in Switzerland in which 2,125 people participated. Using polysomnography, they found out whether people would sleep worse during a full moon. The results showed that the phase of the moon had no effect on the duration and quality of sleep [6] . That same year, American scientists correlated the number of emergency room visits with the phases of the moon. It turned out that during the full moon the clinical load does not change and is comparable to the number of visits on other days [7] .