Friday, July 30, 2010


Townies think the night is dark. It isn't, as long as you can see the moon.

For moderns, the moon is a detail. Do you know what its current phase is?

Townies think that the night is dark because they're constantly dazzled by artificial lights.

But if you go for a walk away from all the lights on a full moon night, you'll realise after about fifteen minutes that it's bright enough to read. You can even see some colours.

Unfortunately every passing car will reset your fifteen minute clock, so you have to go somewhere quite out of the way to experience this.

Where I grew up in the Pennines, it is dark at night, and there aren't that many cars around. But even there, there's enough artificial light in the sky that it's hard to see the galaxy.

Go somewhere truly out of the way, and you will see the Milky Way like a shining band across the sky.

Light a cigar. The match flame will dazzle you.

Wait fifteen minutes for your vision to come back. Then light another behind your back so that the flame doesn't dazzle you again.

You'll find that the light from a lit cigar reflects off the grass! I have heard that frogs can detect single photons. We are not that good. But we are not bad.

That's what true human night vision is like, and it's something that all our ancestors until about 200 years ago experienced every night of their lives.

For our ancestors even until very recent times, the moon was in the same category of importance as the sun. It made the difference between the nights when you could see, and the nights when you were blind.

That's why some traditional calendars use the lunar month as the basic unit, not solar year.

That's why Ramadan, the Muslim holiday, is not at a fixed time of year.

That's why the Passover feast of the Jews is on the first full moon in Spring.

That's why the Easter of the Christians is on the first Sunday after the first full moon in Spring. The Paschal Moon.

That's why your diary probably still follows the weird traditional practice of marking the full moon. What possible use could that be?

Here's Jane Austen in "Sense and Sensibility":

"[Sir John Middleton] had been to several families that morning, in hopes of procuring some addition to their number, but it was moonlight, and every body was full of engagements."

The lit night made a huge difference to what it was possible to do. Back in the days when I could still be persuaded to coach rowing on Winter evenings, it was easy on the night of the full moon, and both impossible and dangerous at new moon. I could always tell you the phase of the moon if asked.

moonchild by ~randis @

moonchild by ~randis @

Women have always been associated with the moon. I know the names of many Moon Goddesses and no Moon Gods.

I am told that women's periods synchronise when they live together. Would they also track the moon if  we lived without artificial light?

Our natural sleep cycle is apparently 25 hours, not 24. It needs the sunlight to reset it every day to keep it accurate. Perhaps the human fertility cycle calibrates on the moon?

Is it impossible to imagine that in primitive tribes all the women became fertile at the same time?

Fertile women find strong men attractive. Men whose wives are straying become madly jealous. Maybe men have monthly cycles too?

Imagine what such a society would be like to live in. Every time the full moon came round, sex and jealousy and madness and anger would disrupt everything.

Maybe that's why lunatics have the moon in their name. Do wolves howl at the moon for the same reason? Is that where werewolf legends come from?

We go to a lot of trouble to conceal exactly when we're fertile, compared to most mammals where it's obvious. That would be completely pointless if everyone could tell just by looking up at the night sky.

Maybe it's the menstrual cycle that synchronizes, but the actual time of ovulation is random within that?

This idea is easily testable, if you can find a small community that lives without artificial light, and find out whether the women all menstruate at the same time. I predict that they do, and that that time is the same fixed point of the lunar cycle for all such small communities.

A second prediction: Sexual jealousy should make men insomniac or at least easily woken. And sexual desire should make women sleepless and prone to going for walks, gazing at the moon.

Is the full moon a good time for affairs? Or is it the new moon, when everything is dark?

Cultural evidence points to the full moon being a special time, but that might be because it's well lit and so a good time for celebrations. The time for affairs might be the pitch dark of the new moon. But if I had to bet, I'd go for full moon as the time of madness.

The moon reeks of romance. It is beautiful and moving. Poets sing of it.

Or alternatively, is the whole thing just an information cascade? Did some ancient sage notice that women's periods were around 28 days and decide that that was close to the moon cycle of about 29 days and so the two must be associated, and from that one observation came all the myths and legends and romantic associations?

You might think that this argument should apply to other species, but this is only going to be relevant if we have a species with sexual jealousy, which has a lengthy regular fertility cycle. It wouldn't surprise me if that was just us.



    Turns out, and this is news to me, that the timing of ovulation isn't predictable. Perhaps this evolved so that even when women menstruate together, they are fertile at different times. Riot avoidance? That way you don't get a village full of sex-crazed women competing for the best guys on the same day!

  2. Where did you get that moongoddess.jpg? It's amazing, I want a blown up poster sized one!

  3. Can you tell me the origin of the Moon Goddess picture?

  4. you made a good point do women and the moon have particular things in common?

  5. Hi John,

    I appreciated this article but am very curious as to why you are apparently using the artwork of an artist on deviant Art without a link back to their work or attribution in its regard.

    It is called moonchild by ~randis @

  6. bcr8tive, I had no idea where it was from! But loads of people have asked, so thanks very much for the link. I'll put an attribution in.

  7. Also ~randis, I tried to leave a comment on your page but my browser kept blowing up. If you don't like me using your picture I'm happy to remove it. If you'd like me to put a specific caption on it then I will (or remove the image entirely if I don't like the caption).