Calendars through the ages - Calendars of the future
"The calendar is intolerable to all wisdom, the horror of all astronomy, and a laughing-stock from a mathematician’s point of view." Francis Bacon 1267
*365.242199 days in a year today, but how many days will there be in a year tomorrow?
There have been many changes in the way that people look at calendars since they were first introduced on earth. It is not as easy as it might seem to align a time measurement system with the solar year and keep days, hours, and minutes, perfectly in tuned with the movement of the earth around the sun. Thus we can be assured that even more changes will be made to calendars in the future. Imagine living in 45 B.C. when Caesar added 90 extra days to the year, or being around when Gregory XIII erased 10 days in an attempt to remedy the overlapping time. What happened to people’s birthdays, vacations, rent payments and paydays that fell during the erased time? Even today, it is expected that the Gregorian calendar will be inaccurate by a full day in a few millennia, though we can be assured there will be additional reform before that time as well.
The first problem arises due to the fact that there is more than one possible year to measure. The sidereal year, measured as 365.2564 days, is the amount of time it takes for the earth to revolve once around the sun relative to fixed stars. The tropical year, which the Gregorian calendar is based on, is 365.24219 days long. Its measurement is derived from the time it takes for the earth to orbit the sun, relative to the vernal equinox. This makes the sidereal year 20 minutes longer than the tropical year and is therefore out of synch with the seasons. In addition, there are 365.24237 days from one March equinox to the next, 365.24162 days from one June solstice to the next, 365.24201 days from one September equinox to the next, and 365.24274 days between two December solstices (Duncan). Since there are different years to measure and different totals for each year, it is hard to tell which one should be used, and which one is actually more accurate. The accuracy of a measurement becomes increasingly harder to determine when exactly ‘what’ needs to be measured is not known.
In 1972, all that changed. Up until then, time was measured in terms of periodic events like the rotation of the earth around the sun or the swing of a pendulum in a clock. In 1972, the International Bureau of Weights and Measures adopted the Coordinated Universal Time (UTC) model as the official time of the world using the atomic clock as its measuring device. An atomic clock can be used to measure a billionth of a second, or .0000000000114079ths of a year. It bases time upon atomic level oscillations – or movement back and forth between particles – of the metal cesium. Cesium oscillates 9,192,631,770 times per second, eliminating the need to speak in terms of 365 days. Instead we can say that the year has 290,091,200,500,000,000 oscillations. It seems unlikely that such a system will be able to catch on in the vernacular; as humans will continue to say “I’m fifteen minutes late,” even if the pulse of the globe insists that they’re actually millions of oscillations past their scheduled arrival time.
Measuring time in terms of oscillations is actually too accurate, something that the originators of the first calendars probably never dreamed could happen. It does not take into account the spontaneous quaking of the earth on its axis, which can throw seconds out of whack. As a result, leap seconds have been added nearly every year for the past three decades to compensate, though none have ever been subtracted. So it appears that the adage “time slips away from us” is still true.
Suggestions for future reform have already been made. Perhaps the most popular is the Fixed Calendar, in which there would be 13 months. Each would be exactly four weeks long, thus eliminating the current problems found in the fact that weeks cycle through at different times during different years. Not every year starts on a Sunday or Monday, pushing dates around to different days and making quarters for businesses and tax paying confusing. “The extra month, Sol, would come before July. A year day placed at the end of the year would not belong to any week or month. Every four years, a leap day would be added just before July 1st” (“Future”). The quest for accurate time measurement allowed the evolution from stargazing to atomic vibration to take place, and surely the process will continue until man has found a perfect synchronization with the world around him… if such a feat is possible.
- Duncan, David Ewing. Calendar. NY: Avon Books, 1998.
- “Future Calendars.” World Book, 2005.