The summer solstice occurs when the tilt of a planet's semi-axis, in either the northern or the southern hemisphere, is most inclined toward the star (sun) that it orbits. Earth's maximum axial tilt toward the sun is 23° 26'. This happens twice each year, at which times the sun reaches its highest position in the sky as seen from the north or the south pole.
The summer solstice occurs during a hemisphere's summer. This is northern solstice in the northern hemisphere and the southern solstice in the southern hemisphere. Depending on the shift of the calendar, the summer solstice occurs some time between December 20 and December 23 each year in the southern hemisphere and between June 20 and June 22 in the northern hemisphere in reference to UTC.
Though the summer solstice is an instant in time, the term is also colloquially used like midsummer to refer to the day on which it occurs. The summer solstice occurs on the day that has the longest period of daylight – except in the polar regions, where daylight is continuous, from a few days to six months around the summer solstice.
Worldwide, interpretation of the event has varied among cultures, but most recognize the event in some way with holidays, festivals, and rituals around that time with themes of religion or fertility.
Solstice is derived from the Latin words sol (sun) and sistere (to stand still).
"Why we celebrate the summer solstice"
June 21st, 2013
Today, the Northern Hemisphere celebrates the summer solstice, the longest day of the calendar year (happy winter solstice to the Southern Hemisphere!). Around 1:00AM, the sun was directly above the Tropic of Cancer—and though I was fast asleep at that precise moment, along with most of my fellow East Coasters, I probably woke up earlier than I normally would, and will go to sleep far later. That’s the beauty of the longest day of the year.
But while the day is, technically speaking, an astronomical occasion, its historical and cultural significance extends far beyond the relative length of the daylight. The word solstice itself comes from the Latin, from sol (sun) and stare or sistere (to stand or stop), and its celebration dates back to ancient pre-Christian tradition. For the Greeks, it would, according to some calendars, mark the start of the new year—and the month-long countdown toward the Olympics. It was, too, often the annual occasion for the festival of Kronia, to honor the god Cronus, the patron of agriculture. The day was marked not only by the typical feasts and games, but by an even more remarkable occurrence: for once, slaves could participate in the festivities along with the freemen, joined in equality for a single day.
For the Romans, the solstice was the occasion for another unique exception to everyday life: on the first day of the festival of Vestalia, married women could, for one day only, enter the temples of the vestal virgins. There, they would be allowed to make offerings to Vesta, the goddess of hearth and home.
Many Native American tribes celebrated the longest day of the year with a Sun Dance, while the Mayas and Aztecs used the day as a marker by which to build many of their central structures, so that the buildings would align perfectly with the shadows of the two solstices, summer and winter. In many European pagan traditions, the solstice was called Litha, a day to balance the elements of fire and water, while for the druids, it was, simply, midsummer, a night and day with properties like no other. According to tradition, certain plants—St. John’s wort, roses, rue, verbena, and the like—acquired properties on the year’s shortest night that they wouldn’t have if picked at any other time. And on this evening, if you were very lucky, you might even catch a glimpse of faeries, who favored midsummer to reveal themselves to the common folk. (Rub fern seeds on your eyelids at midnight’s stroke if you want to spy one—but if you do, be sure to come equipped with rue, lest the pixies lead you astray). It’s only too clear why Shakespeare set his famous comedy during the magic of midsummer’s evening.
The day also figures in religious calendars. With the rise of Christianity and accompanying threat to pagan traditions, the summer solstice became celebrated in many parts of Europe as the day of St. John the Baptist—St. John’s Eve in Denmark, the Feast of St. John in France, the festival of St. John the Baptist in Spain, Ivan Kupala Day in Russia. The Festival of Ivanje in Croatia. In Jewish tradition, it’s known as Tekufat Tammuz, the solstice of the month Tammuz, and legend has it that, on this particular day, no one has a shadow.
But perhaps my favorite story of the solstice comes from the East, from Chinese legend. While the day itself is a celebration of yin, earth, and femininity (in contrast to the winter celebration of yang), there is a separate tradition that I find oddly moving: that of the Duanwu, the Dragon Boast Festival. While Duanwu is always held around the solstice, it does not always fall on the actual astronomical date. Instead, it takes places on the fifth day of the fifth lunar month. Why the strange timing?
The origins of Duanwu are uncertain. But my favorite story is this: it is the exact day on which the poet Qu Yuan committed suicide, in 278 BC. Qu was a descendant of the Chu royal family and rose to prominence both for his lyrical verse and his ministerial prowess (he was both Confucian scholar and, at one time, a minister of the Chu State). When the Chu Kingdom fell to the Qin, Qu drowned himself in despair in the Miluo River. But that’s not where the story ends. Qu was so well-loved—and his display of patriotism so moving—that the townspeople took to their boats in the hopes of saving him, or at least recovering his corpse. When that failed, they decided to throw rice, wrapped in bamboo and reeds, into the river to feed the fish, in the hope that the fish would then leave Qu’s body alone. Each year, on the anniversary of his death, they would repeat the ritual. And so, Duanwu was born—except today, instead of throwing the bamboo-wrapped glutinous rice (called zongzi) into the water, you eat it yourself (and the wrappers no longer contain simply rice; depending on the variation, zongzi can have pork, egg yolk, chestnuts, mushrooms, cabbage, chicken, red bean, and on and on).
There are myriad traditions, myriad histories, myriad reasons to choose from when you celebrate the sun’s longest daytime path. But at the end, we may not need any of them. Maybe, the reason we want to commemorate the day is much more prosaic—and fundamental—than any story or legend will ever be. On this day, we may, quite simply, be the happiest we’ve been in a long time.
Psychologists have long suspected a link between our level of happiness and the amount of sunlight in the day, and even though much of the data has been self-reported and anecdotal (it’s challenging, though not impossible, to run a controlled study with adequate data that spans an entire year), there have been some experimental results that suggest that, comparatively speaking, individuals suffers greater levels of depression when daylight decreases. That is, if you move someone to a more northern latitude (so, one where the days are relatively shorter), he is more likely to suffer an increase in symptoms of anxiety; move him to a more southern latitude, and the opposite is the case. Still, until relatively recently, data collection has hampered a more systematic approach to the question.
Enter social media. In 2011, a group of researchers decided to look at the tweets of some 2.4 million people from all over the world, for a period that ranged from February 2008 to January 2010, selecting 400 tweets at random for each individual. They wanted to see if emotional content varied as a function of the time of day, the day of the week, and the amount of actual daylight (i.e., the season). They found meaningful differences on all fronts—but most significantly for this discussion, they discovered that what mattered most when it came to the time of the year was not the absolute amount of daylight but the relative change in that daylight. That is, was the day, relatively speaking, longer or shorter than the day that came before? When the change in daylight was positive (i.e., in the approach to the summer solstice), people expressed significantly higher positive affect than they did when that change was negative (i.e., approaching the winter solstice).
By the time the solstice rolls around, then, we’ve been on a happiness up-slope for half the year—a build up of positivity if ever there were. No wonder the urge to celebrate runs high. And an even greater reason: it’s all downhill from here on out, relatively speaking – at least for the next six months.
It seems somehow wrong, though, to end such a day on a down note. Better perhaps to turn back to ancient traditions, and see if we can’t increase our luck for the months to come, on this most magical day of midsummer. The options are many. You can light a bonfire—and jump over it if you dare. Succeed, and you may find yourself finding your true love. You can leave a piece of gold jewelry in the sunlight, and wait while it soaks in its power. Wear the jewelry later, and you may find that power transferred to your own life in the coming year. I, for one, may have missed my window. As I found out earlier today, I would have done well to have spent the last night keeping wakeful watch amidst a circle of standing stones (how sad that Stonehenge is so far from New York). Legend has it, such a stunt could kill me or drive me mad—but if it didn’t, would turn me into a great bard, or storyteller.