Preamble: There are five video clips in this wibblette. The longest is just over three minutes long, and they total a smidgeon over ten minutes. Just so you know.
The short clip above, which comes from an hour-long BBC documentary ‘Do We Really Need the Moon?‘, illustrates a theory of how our moon came to be: it’s not proven fact. And yet, it rings true: the Moon was once much closer to the Earth than it now is — it is fact that the Moon is moving away from us (at about the rate our fingernails grow).
The diameter of the Moon is 400 times smaller than that of the Sun. In our epoch, the Moon is 400 times closer to us than the Sun, which means that when the Sun, Moon and Earth are in line, we can see a marvellous thing: a ‘total solar eclipse’. In that same documentary, the narrator (Dr Maggie Aderin-Pocock), like Johannes Kepler trying to find cosmic significance in the fact that our planet Earth is 93 million miles from our sun, admits trying to “find something in the physics to make it so [the apparent size of the Sun and Moon is the same from the Earth]”. She expresses the belief that this size differential is just a cosmic coincidence. But, is it really?
Humans have only been around for about 200,000 years — a mere eye-blink in comparison to the vast time it has taken for the Moon to crawl, at less than a snail’s pace, from its initial position very close to the Earth to where it is now. How, then, can it be that we exist at precisely the right time to view a total eclipse of the Sun? Were the Moon any closer, we’d still get a total eclipse, but not the same magical one we now see; and if the Moon were further away, we would only ever get a partial eclipse. This is the real ‘coincidence’, and it’s this that I call into question.
Now, I’m no statistician, and I do understand that coincidences do happen. But it seems to me that the probability of humanity arising at precisely the time when the Moon is exactly this distance from the Earth incredibly unlikely. We’re talking geological timescales, here. I don’t know how long the window in which this ‘400 coincidence’ would be valid (I’d love to hear from anyone who knows such stuff, so we can have a chance of guesstimating the odds!).
Earlier in that same documentary, Dr Aderin-Pocock discusses the theory that our moon was in part responsible for life itself arising on our planet. (That’s too much for this short article, go watch the documentary if you’re interested.) She’s not the first to suggest this: I came across this idea many years ago in Isaac Asimov’s book ‘The Tragedy of the Moon‘. This ties in with the anthropic principle, which suggests that we perceive the universe to be as it is because if it were any other way, we wouldn’t be here at all to perceive it….
If it’s not coincidence that we exist at the ‘Goldilocks‘ moment when it’s possible to perceive a total solar eclipse, what then could the reason be?
I put it to you that the reason is, quite simply, that the Moon, and in particular this ‘cosmic coincidence’, has played an important part, not just in the generation of life on this planet, but in the creation of intelligent life. Us.
In ‘2001: A Space Odyssey‘, a mysterious obelisk is cast in the role of having imbued our species with the ability to reason. If you read the book from which that movie came, you’ll find that the character having the epiphany in the clip above is named ‘Moonwatcher’. Subtract the fictional obelisk from the scene, and we have a hominid marvelling at the wonder of the factual Moon. Perhaps Moonwatcher encountered that numinous event which is a total solar eclipse. And perhaps it scared him (as it did my nephew when he first experienced that curious darkness). Maybe it scared him into thinking.
It’s long been thought that structures such as Stonehenge were built to chart the passage of astronomical phenomena, including, naturally, the Moon, across the sky. Just think of the prodigious effort that went into such constructions — and how much we humans must by necessity have learnt in the process. Humanity has long had an interest in charting the movements of the Moon in particular: lunar agriculture, for instance, has been practised for thousands of years, and can be traced back to the ancient people of the Nile and Euphrates river valleys.
- Solar eclipses (the Sun being eclipsed by the Moon) reveal the Sun’s corona, a marvel that would otherwise remain forever hidden.
- Eclipses happen on human timescales. The Sun, Earth, and Moon return to nearly identical relative positions every 18 years 11 1/3 days (the Saros cycle).
- Within any given year, a maximum of seven eclipses can occur (either four solar and three lunar or five solar and two lunar) and there is one total solar eclipse somewhere on Earth three times every decade; a high enough frequency to promote study within a single human lifetime.
- A given spot on the Earth will be on the path of a solar eclipse only about once every 370 years, so it is better to move to an eclipse than to wait for one to come to you…
… so move forward in time a little, and humans develop the ability to travel farther away from their birthplaces — armed with the knowledge of when, and where, total solar eclipses can be experienced. Such knowledge would be valuable, sought-after, stuff.
Moving further forward in time: One prediction made by Einstein’s General Theory of Relativity, that massive bodies would bend light, was first proven correct by the observation of starlight passing near the Sun during a total solar eclipse in May 1919. If there were no total solar eclipses, this observational proof would have been impossible to acquire simply because under normal conditions the brightness of the Sun hides the light from any such stars.
Surely this sequence of events is more than mere coincidence. Isn’t it possible that we are who we are, when we are, because of the Moon’s unique position in our sky?
Postscript: Many thanks to Paul Handover (Learning from Dogs), Mark Nunn (East River Meditation Healing Centre), Patricia and Tom who all gave me valuable feedback on this article before it was published.