Nature Studies by Michael McCarthy: The winter solstice, festival of rebirth

Let us celebrate the day then, the long-awaited day, the great midwinter feast, and let us give thanks for what it represents, most of all, its restoration of hope. I'm not referring to tomorrow, though, I'm not referring to Christmas. I'm referring to last Tuesday: the winter solstice.

Not that I have anything against Christmas; far from it. Having been brought up in the Christian fold I love its story and customs and music, in the way that you can if you've been lucky enough to have had them refreshed for you through children, even though they are so naffly commercialised, and even though I recognise that for some people the whole palaver can be a hard-to-admit-it but hateful period of truly glacial loneliness.

But Christmas is something else, another argument. The benefits of the winter solstice are there for all to see: it is the moment when the days stop shortening and start getting longer again (technically, the moment when the tilt of the earth's axis is farthest away from the sun.) It has been celebrated far longer than Christmas has, for many thousands of years – Stonehenge is lined up to the winter solstice sunset – and indeed, it is almost certain that 25 December was chosen by the early Church as the conventional date of Christ's birthday because it was the date of the winter solstice in Roman times.

Now it has shifted (partly because of the replacement of Julius Caesar's Roman calendar with the Gregorian calendar from 1583 onwards) and it occurs on 21 or 22 December. It is not actually a day, but a precisely calculable moment in the earth's orbit around the sun, so this year it was 11.38pm on Monday December 21, but as it had occurred after sunset, the celebration was held the day afterwards.

Many people, however, perhaps even most people, won't have noticed it. In our rush-around urban existence where we no longer see the stars for the street lights, we rarely mark the sunset – we do that on holiday, don't we? – certainly not from neon-litoffices when the sun is disappearing outside at four o'clock in the afternoon. We're out of touch with the winter solstice, just as we have lost touch with most of the earth's natural rhythms – but behind everything, of course, even if unseen by us, they are continuing in all their power.

The solstice represents the most powerful of them all: rebirth. The moment when the days begin to lengthen again is the moment when new life begins its approach, even at the darkest point, which is why it has been so widely celebrated and held as such a feast day in so many cultures right round the world. The miracle of rebirth never ceased to amaze them. Death was being refuted. It was wondrous that new life should arrive quite as unfailingly as old life should die, especially since a human individual's life itself was linear – it only went in one direction. But the great earth was different. It was not linear; it had a cycle, and although you might fear that one year it would break down, it never did.

As we get older, I think we become more appreciative of the miracle (partly, I suppose, because it isn't going to happen to us). What that can mean is an awareness of its annual approach, even though it is buried under life in the neon-lit office, in the canteen, in the bus or the train, shopping, watching television, driving the car. We may be doing all of these things over the next few days and be generally far too preoccupied to notice, but look! It's happening. Sunset tonight is at 15.55, but tomorrow afternoon, when you're recovering from Christmas lunch,it'll be at 15.56. On Monday it's at15.57, and on New Year's Eve it breaks the four o'clock barrier: it's at 16.01.

And so it goes on, in these virtually imperceptible but remorseless gradations, until some time at the end of the first week of March, say, and you're home early for some reason and you look out of the kitchen window at about ten past six and you notice it's still light, and the light has a special cool, relaxed quality to it and this is something different, something new: it's evening. Evenings are back. And you open the kitchen door into the garden and a blackbird is singing from the roof opposite, and a song thrush from the tree next door, both of them liquid and loud, clear on the air in this confident new radiance, and you suddenly realise that the whole world is on the tremulous verge of something immense.

The run-up to that has begun; it began on Tuesday. People have often said to me that their least favourite months are January and February. I've never thought that; I've always least liked November and early December, when the movement is only down towards the dark. January and February are usually much harder in weather terms, of course, and can seem interminable, but since the winter solstice, there is hope in the background: however thick the snow and sharp the frost, however burst the pipe and chaotic the airport terminal, the rebirth is coming now; nothing can stop it.

This column online

A number of readers have been interested in locating previous examples of Nature Studies which have not been easy to find on The Independent website. It should be simpler from now on because the columns have been archived together, in date order; you can find them all by going to the link below.;