Professor Ernest Naylor dismisses the mythology surrounding the Moon's influence, but shows the remarkable effects that it has on our lives.
Above: Engraved map of the celestial hemispheres by the Venetian Pietro Scattaglia from the late 18th century at Oxford's Museum of the History of Science
by Ernest Naylor
From early history the Moon has influenced human culture. Particular moon phases were once considered beneficial for diverse aspects of human life - from hair growth to optimal times for political meetings.
Legends and myths are manifold and some of the mythology lingers even today at Halloween, for example, with its imagery of witches, wolves and bats in silhouette against a lunar face. Timed to All Saints Eve, Halloween is a solar calendar event that causes particular excitement when it coincides with a night of Full Moon, a conjunction that occurs typically every nineteen years, determined by the Metonic cycle of coincidence of solar and lunar cycles. But are all Moon-related phenomena in humans and elsewhere in the living world as mythological as they seem?
Indeed, some biological phenomena have been well documented that even reflect adaptation to the interaction of solar and lunar events in the Metonic cycle. Some marine worms and birds in tropical localities, where seasonal changes in day-length are minimal, show remarkable timing in their breeding behaviour reflecting the change of lunar phase in relation to the solar calendar. Palolo worms off the Samoan Islands spawn at any time during a six-week period in October and November, phased to a night of the third quarter of the Moon, which of course varies in its timing from year to year.
Similarly, Sooty Terns (above) returning to breed on Ascension Island in mid-Atlantic do so within a day or two of every tenth Full Moon, thus appearing to breed at random times throughout a calendar year. Observational and experimental evidence is building up quite strongly to suggest that “circatidal” and “circalunar” clockwork can now be added to that of circadian timing within genomes of living organisms. If that is so then the possibility cannot be excluded that circatidal and circalunar genes, like those of circadian periodicity, also occur in the human genome.
If Moon-related genes, like Sun-related genes are in the human genome they may not explain human behaviours associated with Halloween, which are no doubt based on myth and legend, but they may help to explain recent discoveries which, if confirmed, suggest that cycles of moonlight affect the sleep patterns of volunteers in a sleep laboratory. Without seeing the Moon the volunteers consistently fell asleep more quickly during nights of new Moon.
So, if not Halloween, some of the folklore associated with lunar cycles may yet require scientific investigation if the periodicity of the Moon, like that of the Sun, is embedded in our genes
Above: Engraving of the 'Annular Solar Eclipse of 1 April, 1764' by Joseph Betts of University College Oxford
Ernest Naylor is Professor Emeritus at the School of Ocean Sciences at Bangor University. His book 'Moonstruck' is out with Oxford University Press.
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