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"I know I have the best of time and space, and was never measured and never will be measured." Walt Whitman
This year's June solstice falls on June 20, at 11:59 pm Universal Time. Although that's only one minute before the midnight hour, that still places the solstice on June 20. This is the first time since the year 1896 that the June solstice has fallen as early as June 20. Every June solstice between 1896 and 2008 had fallen on either June 21 or June 22.
By the way, if we convert Universal Time to Eastern Daylight Time, this year's June solstice arrives at 7:59 pm (around sunset at mid-northern latitudes). In North America, you can expect the year's northernmost sunset this June 20.
In the way of review, the June solstice (sometimes called Northern solstice) marks the moment when the Sun reaches its farthest point north of the celestial equator. On the day of the June solstice, the Sun rises farthest north of due east and sets farthest north of due west. For the Northern Hemisphere, the June (Northern) solstice is the summer solstice, ushering in the longest day of the year. For the Southern Hemisphere, the June (Northern) solstice is their winter solstice, whereby they must endure the year's longest night.
Why this Calendar Oddity?
The calendar in use today tries to align itself with the march of the seasons. In humanity's long and arduous quest for an accurate seasonal (tropical or solar) calendar, we have been hampered by the fact that there are not an even number of days in the seasonal year. The Julian calendar that was implemented in 45 BC presumed a seasonal year of 365.25 days. To keep the calendar intact with the seasons, the calendar decreed that three years of 365 days would be followed by a leap year of 366 days. (By this format, any year equally divisable by 4 would be a leap year.) This gallant attempt was eventually undone because the mean length of the seasonal year is about 11 minutes shy of 365.25 days. After more than 1,500 years, the Julian calendar was found to be about 10 days out of step with the seasons.
This led to the Gregorian calendar reform by Pope Gregory in 1582. To realign the calendar with the seasons, Pope Gregory decreed the day after October 4, 1582 should be called October 15, 1582. That next year, in 1583, the June solstice fell on June 22, at approximately 7 a.m. Universal Time (UT). The year following, 1584, was a leap year, with the June solstice falling on June 21, at about 13 hours (1 p.m.) UT.
The Gregorian calendar decrees that leap years are initiated every 4 years, except in century years that are not equally divisable by 400. By this rule, the years 1600, 2000, and 2400 are 366-day leap years, but the years 1700, 1800, 1900, 2100, 2200 and 2300 are common years of 365 days.
The Explanation: 1900 Not a Leap Year
In 1896 (a leap year), the June solstice fell on June 20. In 1897, 1898 and 1899, the June solstice - as expected - fell on June 21. Had 1900 been a leap year, the June solstice would have occurred on June 20. Yet 1900 was not a leap year, so the June solstice fell on June 21 instead. The supression of this single leap year in 1900 made sure that no year at all in the 20th century (1901-2000) would have a June solstice falling any earlier than June 21.
Even though the June 2000 solstice fell on June 21, the fact that 2000 was a leap year is what led to this year's June 20, 2008 solstice. Had 2000 been a common year of 365 days, this year's June solstice would have fallen on June 21. What's more, this century leap year in 2000 assures us that every leap year in the 21st century (2001-2100) from 2008 onward will sport a June 20th solstice. Of course, the year 2100 doesn't count, because it's not a leap year. For this reason, the solstice will occur on June 21 in 2100.
The Gregorian Calendar is A Human Artifact
The Gregorian calendar is a wonderful human artifice that tries to align itself with the natural rhythm of the seasons. Perhaps the Gregorian calendar isn't quite nimble enough to waltz in step with the master dancer. Yet, I think these little missteps or calendar oddities actually exhibit the calendar's inherent grace and beauty, making us all the more aware and appreciative of the intricate dance of the Earth and Sun.
If we choose, we can say it's the calendar that comes earlier or later relative to the solstice, rather than the other way around. It might be a bit mind-bending to look at it this way, but we can also say that this is the latest June 20 since 1896!
copyright 2008 by Bruce McClure
|Graphic Portrayal of the June solstice & Gregorian calendar|
|June Solstice Dates 2000-2020|
May 2008 Feature * July 2008 Feature