IN THE NORTHERN hemisphere, the summer solstice marks the longest day of the year and on that day until the winter solstice, the days get progressively shorter. The winter solstice is the moment when the days begin to get longer again. Just the reverse is true in the southern hemisphere, but the two solstices themselves occur at exactly the same moment for everyone on earth.

The winter solstice in the northern hemisphere is close to the same time as Christmas, and many of our Christmas traditions originated from the days before Christianity, when the solstice was celebrated. Traditions for celebrating the end of shorter days and the beginning of longer days have been practiced around the world for many thousands of years.

At Stonehenge on the British Isles, for example, the huge stones are arranged in such a way that they frame the setting sun on the day of winter solstice. The ancient Brits had a tradition of tying apples to the branches of oak trees in the dead of winter to affirm that summer would come again. The Celts put mistletoe on their altars.

The ancient Romans celebrated the winter solstice by giving gifts. And they feasted a week. Servants traded places with their masters — the masters serving their servants during the feast. They also had a tradition during winter solstice of bringing evergreens indoors.

In the Scandinavian countries, the sun disappears in the dead of winter. In the far north, it disappears for as long as 35 days. The ancient people of the far north had a tradition of feasting when the dark days were over and the sun once again shone on the horizon. They celebrated with what they called a Yuletide festival. They feasted in a long hall while a Yule log burned in the fireplace. They thought of mistletoe as sacred. Kissing under mistletoe was a fertility ritual. Holly berries was considered to be the food of the gods.

The solstice celebrations were officially replaced with Christian ceremonies during Roman times as a way of overtaking the ancient traditions, even though Jesus wasn't really born in December. It was a political act. December 25th used to be the solstice with the old calendar. Now it almost always happens on December 21st with the modern calendar.

But the Christian usurping of the celebration was a long time ago. We could celebrate the solstice instead of (or in addition to) our other celebrations. We could celebrate the turning of the season. We could celebrate longer and warmer days ahead. We could keep our celebrations, but change the date, and that way more people could celebrate together. People of different customs could celebrate their customs but also celebrate the solstice with all people.

The solstice has nothing to do with religion, race, or nationality. Every one of us relies on the sun for our warmth, our sunlight, and our food. The time and date of the solstice can be accurately determined and it occurs at the same moment everywhere on earth.

The solstice might some day become an international holiday. This could be the beginning of something wonderful: a point of unification, a place of agreement, a universal tradition.

You can begin this year by celebrating the solstice in even a small way. Take any of the traditions normally associated with the holiday season and do some part of it on the solstice. Give a gift. Eat a feast. Be kinder to your fellow human beings. Invite people of all faiths to your home to celebrate the end of the longest night and the beginning of longer days. The celebration of the solstice in your own home could actually and concretely work for peace on earth and goodwill toward men and women.