What Day Is It? - World Calendars Quiz

Answer: Calendar transition occurred during Washington's lifetime

When Washington was born on February 11th, England and its colonies still observed the Julian calendar. During his lifetime, they adopted the Gregorian calendar and skipped eleven days in doing so.

This obviously required adjustments to schedules and business transactions. Less obviously, it offered people the option of when to celebrate their birthday. Washington chose to use the date (February 22nd) based on the new calendar, which was the day he would have been born on if the Gregorian calendar had been in use at that time in the US.

Answer: Flight of Muhammad from Medina to Mecca

The Islamic calendar year is based on the Hegira, Muhammad's flight from Medina to Mecca in the year 622 of the Julian calendar. Events that occurred prior to that are denoted by the years before the Hegira (bH) in the same manner that the Gregorian calendar uses BC or BCE.

The conversion of dates between the Islamic calendar and the Gregorian one is complicated by the fact that the Islamic calendar is a true lunar calendar, rather than a solar one. The Islamic year of 12 lunar months has 354 or 355 days, and so calculation of the current year requires more than subtracting the year of the Hegira from the Gregorian year.

Answer: It's 7 or 8 years behind the Gregorian calendar

One of the issues with calendars is what defines the starting year. Many early calendars used a regnal year, based on when the current ruler began his reign. Later the need for a common historical reference point caused calendars to select a single event as the starting year. These include estimates of creation dates (Hebrew and Chinese), the founding of the Government (Roman), and dates of religious significance (Christian and Islamic).

The use of the supposed year of Christ's birth as the reference year in Christian calendars occurred surprisingly late. The starting year based on the Incarnation of Christ was introduced by Dionysius Exiguus in 525 and became widely used after Bede incorporated it into his history.

The actual year of Christ's birth is disputed, and many authorities think the actual year was between 4 and 6 BC based on historical and astronomical events mentioned in the Gospels.

The Ethiopian calendar uses the Annunciation or Incarnation of Jesus on March 25, AD 9 (Julian), as calculated by Annianus of Alexandria; thus its first civil year began seven months earlier on August 29, AD 8. This causes the Ethiopian year number to be eight years less than the Gregorian year number from January 1 until September 10 or 11, then seven years less for the remainder of the Gregorian year.

Answer: Calends

The Roman calendar evolved over the course of the Republic. Originally it was a lunar calendar, and the calends, nones, and ides derived from the first sighting of the crescent moon, the first-quarter moon, and the full moon respectively. These were the 1st, 7th, and 15th day of the months for those with with 31 days, and the 1st, 5th and 13th days of shorter months.

The original Roman calendar had ten lunar months, starting with March and an unnamed winter season that could be expanded by the leaders to align with the solar year. The year was also divided into 38 nundial cycles of eight days each to create market days.

Julius Caesar introduced calendar reform in 46 BC that changed it to a solar calendar of 365 days with a leap year every fourth year. The months of January and February were added at the end of the calendar year (before March) to replace the winter period.

After Caesar's assassination Mark Antony had the fifth month Quintilis renamed for Caesar. The sixth month Sextilis was later named for the Emperor Augustus. Later emperors also renamed various months, but none of these changes lasted beyond their death.

Answer: 1752

The Julian calendar used a solar year of 365.25 days, which is slightly longer than the true length of time. Adding an extra day every fourth year caused it to fall behind the true solar date by about one day per century and the calculation of Easter, which is based on the vernal equinox, started to move from spring.

In 1545, the Council of Trent authorized Pope Paul III to reform the calendar. For many years studies were conducted to determine the date of the vernal equinox and the number of leap days required to keep the calendar in sync.

In 1582, Pope Gregory XIII proclaimed the new calendar, which was soon adopted by countries with Catholic rulers, but resisted by countries under Protestant and Orthodox rule. Prussia in 1610 was the first of these to adopt the new calendar, although the next major countries to join didn't occur until the 1700s. The last holdouts were Orthodox-led countries, Russia in 1918 and Greece in 1923.

So for over 100 years, Western Europe used two different calendars for civil and religious purposes.

If one really cares, there has been some discussion that the current leap year logic adds one extra leap day every 4000 years. Hopefully the pope or civil authority who resolves this issue, raised by 18th-century astronomer John Herschel, meets less resistance.

The Julian calendar is still used by some Orthodox churches and surprisingly (at first glance) by one science. Celestial orbital data is maintained in ephemeris files that extend to the distant past. The days advanced by introduction of the Gregorian calendar are an artifice. So calculations must convert (Gregorian) current time to a Julian date and remove the effect of daylight savings and leap seconds to be consistent with ephemeris data and orbital calculations based on time.

Answer: Mayan calendar

The Mayan calendar is similar to calendars used by other Mesoamerican civilizations. One of the methods of counting years uses the "long count", a vigesmal (base 20) system with up to nine numbers in the count. Currently only 5 of the counters need to be used.

The year is currently specified by a string in the form of "A.B.C.D.E". The lowest number (E), called the K'in, is the day (1-20) of the month. The next number (D), called the Winal, is the month (1-18) of the year, defining a year of 360 days. C (Tun), B (K'atun), and A (B'ak'tun) form the year by the base 20 system (A*400 + B*20 + C).

On December 21, 2012, the long count transitions to 13.0.0.0.0, the start of a new B'ak'tun. Social media experts and New Age philosophers had predicted the end of the world or a cataclysmic event would occur on this date based on a prophecy based on the end of a cycle (going to Baktun 13) in the Mayan calendar.

The hubbub came from a Mayan stone carving, made in 700 A.D., which predicted a major event at the end of this B'ak'tun. But half of the broken tablet is missing, so one may only speculate on what the complete message was.

Other ancient calendars give importance to cycles that may define new stages in life. Even in Western worlds we attach significance to the end of decades, centuries, millennia, or new astrological ages (remember the Age of Aquarius).

While it is easy to dismiss events based on the year number, there was much discussion of possible breakage of transitioning to the year 2000. Incidentally, not that we personally need to worry about it, there will be a very significant Y10K problem when humans (if we're still here) have to deal with our year transitioning to 5 digits and worrying about 8 millennia worth of four-digit years on digital records.

Answer: 354 or 355 days (12 lunar months)

The Islamic or Hijri calendar is a true lunar calendar, in which a year consists of 12 lunar months. Each month follows the same lunar cycle, starting with the observation of the crescent moon. In some Islamic countries the start of the month is based on local observations, but in others it is based on observations at Mecca.

The lunar month spans 29 or 30 days, which means the year will be 354 or 355 days. Many other calendars which follow the lunar month periodically add an extra month (lunisolar calendars) to keep it better aligned with the solar year. The use of the shorter lunar year causes fixed dates to occur in different seasons over a cycle of approximately 34 lunars years (33 years on solar or lunisolar calendars).

Most Islamic countries use the Hijri calendar for religious purposes, such as determining the time fasting (month of Ramadan) and the proper time for the Hajj. However, the Gregorian calendar is now widely used for civil purposes.

Answer: Hebrew calendar

The Hebrew calendar has a corresponding year number of AM 5781. The 12th-century scholar Maimonides performed a major update to the calendar. Before that time it counted the years from the destruction of the Temple of Jerusalem. Maimonides revised that to an Anno Mundi (AM) basis, the time from the creation of the world based on his calculations.

The Chinese calendar has a corresponding year number of 4719. Although different systems of calculating the year have occurred in history, the current calendar uses the date of the ascension of the legendary Golden Emperor to the throne. The first calculation was performed by Jesuit missionary Martino Martini to be 2697 BC. The modern calendar, approved at the beginning of the Chinese Republic, moved the start date slightly to 2698 BC.

The Persian calendar is currently at year 1400. At one time the Islamic calendar had been used in Persia, but it caused a disruption to the economy due to the shorter year and shift in the seasons. Omar Khayyam, who besides being a notable poet was a distinguished mathematician and scientist, designed a solar calendar that used the Hegira as the starting year. Shah Pahlavi redefined the starting year of the calendar in 1976 to the beginning of Cyrus the Great's rule. However, it reverted to the Hegira after the Iranian Revolution. The Iranian calendar is a Solar Hijri calendar (365 or 366 days), and its current year is 1400 versus year 1442 of the Islamic calendar due to the fact that 34 years on the shorter Islamic calendar are roughly equal to 33 years on a solar calendar.

The Buddhist calendars are lunisolar, like the Hebrew calendar, and require periodic insertion of leap months to align with the solar year. There are some variations in the year of Buddhist calendars used throughout Southeast Asia, based on the year Buddha attained Nirvana (varying between 543 or 544 BC). It is approximately year 2563 BE (Buddhist Era).

Answer: Before the last month (Adar) of ecclesiastical calendar

The Hebrew calendar is the official calendar of Israel and is also used in other countries for religious purposes. The calendar is a lunisolar calendar in which each month follows a predetermined cycle of the moon. The lunar year is about eleven days less than a solar year, and an additional month is added every second or third year according to a cycle determined by Meton of Athens in the 5th century BC.

The first month of the calendar Nisan begins in March of the Gregorian calendar, and the last month Adar corresponds to February-March. When a leap month is added, it is placed before Adar and referred to as Adar I. All feast days that normally occur in the month of Adar occur in the following month, referred to as Adar II.

The rule for adding leap months varies among different lunisolar calendars.

Answer: French Republic (Revolutionary) calendar

One lasting result of the French Revolution was decimalization, primarily in the use of the metric system for measurements. However, a far less successful effort was tried in decimalization of time and calendars. The French day was redefined as ten hours, with 100 minutes per hour and 100 seconds per minute. To make the concept of 100,000 seconds per day work, the French second's length had to be defined as .864 conventional seconds.

The French calendar defined a month as three 10-day weeks. Five or six days were added to the end of the 12 months to align it with a solar year. The names of the months were renamed to natural or weather-related events. A special rural calendar was introduced which gave names to each day of the year based on tools, animals, and farm products to replace the traditional calendars that had religious feast days and saints days.

The Roman calendar initially had market days every eighth day for what might be considered a week. But gradually the seven day week, introduced through Jewish, Christian, and other Eastern influences, became predominant.