Like so many of our holidays, Halloween has an astronomical origin. It dates back to a time before the Christian era when people measured the change of seasons not according to arbitrary dates on the calendar but by what they experienced in the heavens and on Earth.
In fact, many Christian holidays were astronomically celebrated long before there were Christians.
In northern climes, perhaps the most important days are the solstices and equinoxes. When the sun reaches its most northern point and the day is longest, we celebrate the official beginning of summer, the summer solstice. When the sun is farthest south and the daylight hours are at a premium, we celebrate the beginning of winter, also known as the winter solstice or, well, Christmas.
Measured against nature, those dates seem poorly placed. For example, from northern latitudes, winter seems well underway before the end of December.
Directly between the solstices are the equinoxes, when day and night are about equal. The equinox between the winter and summer solstices marks our traditional beginning of spring, the vernal equinox. Between the summer and winter solstices is the autumnal equinox, the beginning of our fall season.
However, the blaze of colorful tree leaves that lets us know that fall is really here is happening only now as we celebrate Halloween. Most years, the days after Halloween mean increasing cold, and in earlier years, the very last harvest of the year. To our forebears, the lack of food and warmth defined wintertime.
That’s one of the reasons why many ancient cultures celebrated the days half way between the solstices and the equinoxes, which astronomers call cross-quarter days. The cross-quarter day between the autumnal equinox and the winter solstice signaled for them the onset of winter and a very important festival.
Like many of our old traditions, Halloween dates back thousands of years to the British Isles and to the Celts, who inhabited what we now call Ireland, Scotland and Wales.
The Celts were seasonally deficient from our point of view. They split up the year into two parts, the light and the dark. The light period was associated with the abundance and joy that only the life-giving brilliance of the sun can provide. The dark period and its lack of sun meant hunger and privation.
Starting during the fifth century BCE, they celebrated their Samhain (pronounced SOW-in) festival at the end of October near the cross-quarter day between the spring equinox and the winter solstice. Samhain means “summer’s end” and the beginning of the cold, hard winter. It was for them one of two seams between the seasons. It was also a seam between our natural world and the supernatural world.
Through that broken seam would flow the spirits of the dead to damage their crops and spread evil throughout the countryside. At particular risk were the living relatives of the dead. Their ghosts would come calling in search of food and perhaps, if they were satisfied, no harm would come to the house. If they weren’t, nothing good would follow.
It was a time of urgent and deeply felt fear. As EC Krupp writes in Beyond the Blue Horizon, “An encounter with the spirits on Samhain night guaranteed traffic with hags, monsters, witches, and fairies. Powerful supernaturals who commanded magical forces, the Celtic fairies could help mortals or lure them to their doom.”
What to do? To protect their food stores, people buried apples along the side of the road to give the dead something to eat. They wore disguises to trick their dead relatives into thinking they were somebody else. Supplicants would go from door to door begging for contributions of food from their neighbors.
People left their doors open so that their dead relatives could enter and leave freely. It was better to provide a hospitable “treat” than suffer the consequences of a ghostly “trick.”
It was a time of animal sacrifices and sacred bonfires, lit by priests called the Druids, to appease the Celtic wraiths and enlist their aid in predicting future events.
If some of this sounds familiar, you should note that the Christians did their best to replace the old local festivals and holidays.
In 835 CE, the Catholic Church made Nov. 1 All Saint’s Day, the antithesis of the old, demonic celebration. But they were also quite clever about tolerating some of the practices of older holidays. Samhain became All Hollow’s Eve (or Halloween for short), the day before the Saint’s Day.
Over the centuries, the supernatural Halloweenish practices became meaningless — but fun-filled — rituals for children and an excuse to release yet another vapid horror movie to a theater near you.
So as you hand out treats to the wandering on Halloween, celebrate also your ancient past and the cross-quarter day you are inadvertently emulating.
And lest you think that this connection to the Celts is atypical, consider that on the Christian holiday of Christmas, you will bring a tree indoors. In it is a tree spirit that, as some old cultures believed, will bring good luck and health to your hearth and home.
And on the next cross quarter day at the beginning of February, you will celebrate Imbolg, the Celtic festival anticipating the promise of spring. The name probably means “ewe’s milk,” a reference to the upcoming birth of the lambs and the spring abundance it implies.
On that day, you will look to another mammal to find out how long you will be cursed with cold, hard winter. Yes, that’s right. Groundhog Day is what remains of the old cross-quarter-day extravaganza.
Tom Burns is director of the Perkins Observatory in Delaware.