Since man became conscious of himself as part of a bigger world and universe, he has looked up to the stars and contemplated them. What are they made of, what is their purpose, why do they shine so brightly? Even though the stars are light-years away, over time humans have found a way to use the stars to answer questions found on Earth. Whether used to predict the future, set courses to sail by, or as a way to mark our infinitesimal time on Earth, the stars and the calendars made because of them, are indelibly linked to the human experience. The intent of this paper is to delve into the various civilizations that have been guided in some way by the stars and calendars, discuss how they have used them, and show how the stars have altered human history.

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Ancient and Modern History
Calendars have been used through the ages to systematize and standardize hunting, sacred religious rituals, planting and harvesting, holidays, and timestamp documents (Fraser 586). The purpose of all calendars, though, is to track time. Calendars can be based on the movements of the moon (lunar), the sun (solar), a day, a combination of the moon and sun (luni-solar), or it can be considered arithmetic and free from the constraints of astronomical concerns. For example, the Jewish and Islamic lunar calendars require a new moon to be seen (Fraser 587).

The Babylonians were the first ones to discover new ways to determine when a new moon could first be seen (Fraser 588). Observational calendars require a new moon or other natural event to occur to know the start of months and years, although these types of calendars have fallen out of favor (Fraser 587). In the Egyptian calendar, the constellation Sirius began the New Year (Fraser 588). More modern methods of seeing a new moon use “celestial mechanics, spherical astronomy, selenology, atmospheric physics, and ophthalmology” (Fraser 588). Even our days of the week are named for seven heavenly bodies that can be seen with the naked eye (Fraser 588).

Although many civilizations have used the stars and calendars, only four of the most important will be discussed here. These are the Roman, Mayan, and Gregorian. Other interesting topics which will be addressed are the differences between a lunar and solar calendar and the potential use of Stonehenge in astronomical matters.

Lunar vs. Solar Calendars. Most calendars are designed to take the seasons and the cycles of the moon into account. In these lunar-based calendars, each month is adjusted to reflect to lunar cycle for that month (Richards 585). This attempt to reflect lunar fluctuations is why extra days and leap years were added to the calendar (Richards 585). While many countries around the world use the solar Gregorian calendar, others do not. The lunar-based Islamic calendar, for example, is still relevant for half a billion people (Fraser 84). The Islamic calendar strives to coordinate the lunar machinations and the months, but does not attempt to synchronize the months with the Sun as a solar calendar would (Richards 585). Other calendars try to form a hybrid calendar based on both the moon and the sun (Richards 585).

Roman Calendar. In 46 B.C., Julius Caesar adopted the Julian calendar (Cohen). This was used in many countries of the world until 1582, when Britain implemented the Gregorian calendar instead (Cohen). While this calendar was used for centuries, it did have problems. Primarily, the length of the solar year, upon which the Julian calendar was based, was wrong. In fact, it was wrong by 11 minutes. This compounded annually to create increasingly problematic disparities between the true solar year and the Julian calendar used to represent that year (Cohen). To try and correct this problem, an additional day was added at the end of February every four years (Cohen). Unfortunately, in an attempt to correct one problem, another was created. The addition of these leap year days actually meant that the calendar was now too long (Cohen).

Mayan Calendar. The Mayan calendar is actually comprised of three different calendars and almanacs. These go back as far as 2000 BCE and were used by many in the Mesoamerican area; some still use it today (Time and Date). The calendars are named the Long Count, the divine calendar, and the civil calendar (Time and Date). These must all be used concurrently. The divine and civil calendars name which days, while the Long Count supplies the year (Time and Date). The Long Count is the interesting calendar in that it is the one people thought predicted the end of the world. This calendar works in cycles, with the last big cycle ending in 2012 – hence the Doomsday predictions (Time and Date). It can deal with very large periods of time. The Mayans named this the “universal cycle” (Time and Date). Each cycle is 7885 solar years. The Mayan believed that at the end of this period, everything would be destroyed and remade. This final day of the Mayan cycle aligns with the December Solstice (Time and Date).

The Mayan calendar is most well-known for its supposed prediction of our collective doom. However, many have said that the Mayan calendar is simply misunderstood; it is not predicting doom, but rebirth (Nat Geo). In 2012, many feared that the ending of one of the Mayans’ calendar “cycles” spelled the end for humanity (Nat Geo). Then, that same year William Saturno found calculations in a Mayan ruin that pointed not to apocalypse, but continuation (Nat Geo). These calculations were found to reach approximately 7,000 years into the future (Nat Geo).

Stonehenge. Stonehenge has always been a mystery for modern man. It was built in Wiltshire, England between 3000 – 1500 BC, but why was it created? How was it created? While a completely accurate answer is unknown, there is speculation. Some believe it was actually an observatory used to determine the most important days for Druid worship (Fraser 47). With its monumental size, it is reasonable to assume that it was crucial to those who built it (History).

Gregorian Calendar. The Gregorian calendar was created by Aloyus Lilius, an Italian (Cohen). It is considered a solar calendar rather than a lunar one, meaning it is concerned with accurately reflecting the astronomical year rather than the phases of the moon (Richards 585), however, it is currently considered an arithmetic calendar that is set up according to certain rules and maintains no real ties to any astronomical body (Fraser 588). In 1582, this calendar was promoted by Pope Gregory XIII in the first year of his papacy as a replacement for the Julian calendar (Fraser 79). The purpose of the Gregorian calendar was to realign the calendar with the seasons, and specifically, with Easter (Cohen). Since the year according to the Julian calendar was incorrect by 11 minutes, over time Easter day had moved further and further away from March 21 and the spring equinox (Cohen). Historically, this had been the time Easter was celebrated. Almost 200 years after it was created, in 1752 Britain converted from the Julian calendar to the Gregorian calendar (Cohen). The Gregorian calendar more accurately followed the solar year than the Julian calendar, however it was still out of sync by 26 seconds (Cohen).

While this calendar is the one used today by people all over the world, this was not always the case (Cohen). Pope Gregory was able to affect the Catholic Church and even Catholic countries such as Spain and Italy, but Protestant countries were not so easily swayed from the Julian calendar (Cohen). This was largely due to fear. Protestant countries were afraid the Pope’s new calendar was actually another way the Catholic Church was trying to disband and discredit Protestantism (Cohen). This may not have been an unreasonable concern, however, since Pope Gregory threatened excommunication to those who did not embrace his new calendar (Fraser 84). In the end, some Protestant countries such as Germany and England refused to adopt Gregory’s revisions until the 1700s (Cohen). Other countries with Orthodox views have refused to switch over at any point and still use the Julian calendar today (Cohen).

While the calendar and application of stars and their movements have their birth in antiquity, they are still crucial in the modern age. They are so crucial in fact, that there are currently more than forty or so in use today (Fraser 84). Whether the calendar is based on a lunar, solar, or hybrid concept, it is tied directly to our days, weeks, months, and years and as such, has become inseparable from our daily life.

  • Cohen, Jennie. Six Things You May Not Know About the Gregorian Calendar. 13 September 2012. Web. 27 April 2016. .
  • Fraser, J. T. Time; the Familiar Stranger. Amherst: University of Massachusetts Press, 1987. Print.
  • staff. Why was Stonehenge Built? 10 2013 April. Web. 27 April 2016.
  • Richards, E. G. “Calendars.” Explanatory Supplement to the Astronomical Almanac. Ed. S. E. Urban and P. K. Seidelman. Mill Valley: University Science Books, 2012. 585 – 624. Print.
  • Time and How Does the Mayan Calendar Work? 2012. Web. 27 April 2016. .