A Black Moon is the Blue Moon’s darker counterpart. That is, the second new moon in a single month. But does it have any effect on humans?

“Once in a Blue Moon” is a commonplace phrase, referring to the rare case we see two full moons in a calendar month. But despite the saying, blue moons are more common than you might think.

Then why is a Black Moon unusual? And is there any solid scientific evidence that the moon can affect humans?

From mood and menstrual cycles, to sleep and even sanity, is it all just werewolf folklore? 

Dog, Wolf, Yelp, Moon, Tree, Night
Wolf howls at full moon. Photo credit: Pixabay

Once in a Black Moon

Last night, just before 4 AM on 19 August, here in the UK, we saw the second new moon of the month. Except, even if for some reason you were stargazing at that time, you wouldn’t have spotted it. 

The new moon phase occurs when the moon is passing through the same patch of sky as the Sun. As such, light reflected off the moon is directed away from Earth. So, for us, there isn’t anything to observe.

The only exception is when it’s a solar eclipse and the moon blocks the sunlight, but this wasn’t one of those cases.

As for the next Black Moon, that won’t happen until April 30th, 2022. The average gap between Black Moons is the same as for Blue Moons: 32 months. 

So, if the Black Moon is just the less visible cousin of the Blue Moon, why has it been causing a stir? The answer is, of course, myths. 

Celestial influences

Our moon has long been the subject of fairytales and widespread human fascination. And that’s to be expected. Before the invention of the telescope, it was one of the few celestial bodies we could observe in any detail. 

The advent of the scientific method has debunked many previously held beliefs. Flat Earth theories and other disproven understandings of the world are, thankfully, reserved for the fringes these days.

In spite of this, astrology columns and ideas about the moon are still popular, even in technologically advanced countries with full access to education.

The Dark Moon has brought to light numerous theories that lack scientific backing. If you were to believe everything you read online, all your problems could be explained by the mysterious motions of our lunar satellite. So, let’s debunk some of these claims. 

Earth, Globe, Moon, World, Planet
Moon and Earth. Photo credit: Pixabay

Misconceptions about science

Scientific studies deal in probabilities. For a result to be classed as significant, scientists need to be 95% confident that what they see is real, and not a result caused by randomness. 

Still, this means that, by the laws of statistics, 1 in 20 of the significant results published in well-respected journals, may show a random correlation. 

That doesn’t need to be an issue, since there is emphasis on reproducing results. One paper might report a random result, but if other research teams consistently reproduce the results, scientific confidence in the result eventually grows. This is how we have become extremely confident of theories like evolution and general relativity. 

However, not many newspaper reporters fully appreciate this, and instead take what they find in journals to be exciting new facts. There are thousands of scientific papers published every week. Journalists cover them as fact, and not part of a wider investigation. 

It’s because of this you might read that coffee is detrimental to your health one week, and essential for your wellbeing the next.

So, what are some moon misunderstandings? 

Claims connecting the moon and human health range from sleep, to menstrual cycles, to violent episodes. Across the board, there is no conclusive scientific proof that the moon affects our mental and physical health.  

Individual papers have claimed significant results. For example, a 2013 study (of just 33 people) found a full moon could disrupt the ability both to fall asleep and maintain a deep state of slumber. But attempts to replicate these results failed

Moon, Sea, Full Moon, Light Reflections
Full moon above sea. Photo credit: Pixabay

The outdated word ‘lunatic’ comes from the equally outdated belief that the full moon invokes violent, werewolfish behaviour. Even as recently as 2007, Brighton police decided to put more officers on patrol during full moons, based on their own research

A fundamental misinterpretation of statistics and correlation is the foundation of such lunar myths. One day, I’m sure these ideas will be looked back on with the same derision we currently (and smugly) reserve for beliefs held by the ancient Greeks or Aztecs. 

Black Moon effects are unlikely, but not impossible 

The effect of the moon on ocean tides is well-documented. Recent studies show oysters and many marine organisms are, indeed, influenced by the lunar cycle. 

Science tells us we can be confident that the moon isn’t affecting us most of the time. It also doesn’t completely rule out that the moon could have some environmental impact on our sleep or mood. After all, it is a key part of our Earthly neighbourhood.

But, as with the Black Moon, be aware the next time someone uses ‘scientific studies’ to support a dubious sounding claim. Hopefully you can help explain to them how they might be misusing the statistics. 

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