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ATLANTIC SKIES: Is human behaviour linked to the moon?

Why do people attribute human behaviours to the moon? According to Glenn Roberts, the belief dates back to the ancient Romans.
Why do people attribute human behaviours to the moon? According to Glenn Roberts, the belief dates back to the ancient Romans.

The moon, especially the full moon, is a fascinating celestial object for many people, perhaps because it is the object that we can see the easiest and the most often in the sky.

Except for a few moments at sunrise and again at sunset, we can't really gaze directly at the sun, as its blinding light is just too intense, to say nothing of the damage it would do to our eyesight from its harmful UV radiation.

With the moon, however, we don't have that problem, as the moonlight we see is only sunlight reflected off the moon's surface and radiating towards Earth.

So why is it that people attribute a lunar influence to human behaviours and emotions?

I'm sure most of you have heard the phrase that the full moon "brings out all the crazies" - a belief that the moon somehow affects people's brains to the point that they are no longer in control of themselves, and are, thereby, subject to all sorts of harmful, illogical, crazy, or even dangerous behaviours and/or emotions. As a result, we get the word "lunatic" from the Latin, referencing "Luna" - the Roman goddess of the moon.

Unless you are prone to turning into a werewolf (known as 'lycanthropy') when the full moon rolls around each month (as seen in the movies, and as has been said of my Great Uncle George), one could readily dismiss such beliefs as superstition or folklore. But where did this belief actually come from?

It is thought to have originated in ancient Roman times when such famous scholars and theologians as Plato and Pliny the Elder postulated that the human brain was the "moistest" organ in the human body, and, as such, subject to the same gravitational influences as were the Earth's tides. This led other scientists to formulate the theory that, since the human body is approximately 45-75 per cent water (it varies depending on your age), it was possible that the moon influences the human state of mind, emotions, and behaviours.

We now know, despite a number of bogus studies attempting to link the moon's phases with human mental states, behaviours, and feelings, that there really is no solid proof of any lunar gravitational influence on the human mind or heart (though I'm sure some poets will disagree with me!). Modern astrophysicists have proven that the gravitational pull of the moon on humans is non-existent.

There have, however, been a small number of legitimate studies that indicate that some people's sleep patterns are noticeably disrupted by the moon, particularly around the time of the full moon (which is up all night). Exactly how and why this is the case has not yet been firmly established, although sleep scientists surmise that the extra illumination afforded by the full moon encourages some people to stay up later, and, thus, get less sleep. A recent online article about the Feb. 27 "Snow Moon" attributed the increased illumination of the full moon on the snow as being the culprit in disrupting certain people's internal circadian rhythm (the regulation of sleep-wakefulness periods).

Suffice it to say, that while the moon's light may cause some people to have trouble falling asleep from time to time, there is no definitive proof that the phases of the moon influence our emotions or behaviours...unless, of course, you're Great Uncle George.

This week's sky

With a clear sky and an unobstructed view of the southeast horizon you just might (use your binoculars) spot Mercury, Jupiter, and Saturn in a line, low to the horizon, about an hour before sunrise on the mornings of March 8-10.

Saturn (magnitude +0.7, in Capricornus - the Seagoat) will rise first, followed by bright Jupiter (magnitude -2.0, also in Capricornus), and lastly by dim Mercury (magnitude +0.03, in Capricornus as well). The three planets will extend in a row upward along the ecliptic ( to the right from the horizon).

Use the waning, crescent moon, if you can see it, as a guide to spotting the planets; it will be to the right of the planets on March 8, dropping down below them by March 10. You'll have to be quick if you want to spot these planets, as the rising sun will soon wash away any view of them.

Mars (magnitude +1.0, in Taurus - the Bull) is visible as the dusk sky darkens, approximately 58 degrees above the southwest horizon around 6:50 p.m., dropping below the horizon shortly before 1 a.m. The planet Venus is still too close to the sun to be observable.

If you haven't yet seen it, look for the Zodiacal Light (see last week's article) above the western horizon just after sunset on the evenings leading up to and just after the new moon on March 13.

Don't forget to set your clocks ahead one hour, as we "Spring Ahead" into Atlantic Daylight Savings Time (ADST) on Sunday, March 14, at 12 a.m.

Until next week, clear skies.


  • March 8-10 - Waning, crescent moon near Mercury, Jupiter, and Saturn in the southeast sky, one hour before sunrise
  • March 13 - New moon; Mercury at perihelion (closest to the sun)
  • March 14 - Atlantic Daylight Savings Time begins

Glenn K. Roberts lives in Stratford, P.E.I., and has been an avid amateur astronomer since he was a small child. He welcomes comments from readers at [email protected]


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1 being least likely, and 10 being most likely

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