Year zero
From Open Encyclopedia
- See also 0 and Year Zero (political notion).
- For the album, see Year Zero (album).
A year zero does not exist in the Christian Era and thus also does not exist in our current – internationally recognised – calculation of times.
The Roman numeral system has no symbol for the null. The so-called Arabic numeral system was developed in India at the end of 5th century and so approximately contemporaneous to Dionysius Exiguus who calculated in 525 that after the end of the 13th metonic cycle of the Diocletian or Martyr Era in the year 247 (=13x19) i.e. A.D. 531, it should be passed about 15 additional metonic cycles since Jesus birth. So he decided to mark the first year of his new series of Easter tables as the year D.XXXII since Incarnation equals (15+13) x 19. However, the Arabic numerals were totally unknown in Europe till about the end of the first millennium and not generally used before Renaissance time.
Therefore since Bede historians have not counted with a year zero. This means that between, for example, 500 B.C., July 1 and A.D. 500, July 1 there are surprisingly only 999 years. However astronomers, for whom ease of mathematical calculation is more important, since several centuries use a defined leap year zero equal to BC I of the traditional Christian era.
In common usage Anno Domini 1 is preceded by the year 1 BC, without an intervening year zero.[{{fullurl:}}#endnote_order] Thus the year "2006" actually signifies "the 2006th year." Presently only the astronomers employ a year zero. Neither the choice of calendar system (whether Julian or Gregorian) nor the era (Anno Domini or Common Era) determines whether a year zero will be used. If writers do not use the convention of their group (historians or astronomers), they must explicitly state whether they include a year 0 in their count of years, otherwise their historical dates will be misunderstood. No historian includes a year 0 when numbering years in the current standard era. Thus, regardless of the appellation or calendar employed (Julian or Gregorian), 1 BC (or 1 BCE) always immediately precedes AD 1 (or 1 CE). Historians even refuse to use a year 0 when using negative years before our positive era, hence their −1 immediately precedes 1 (for example, V. Grumel, La chronologie (1958), page 30).
The anno Domini method of numbering years was not widely used in Western Europe until the 9th century, and the 1 January (however the Caesar's New Year's Day) to 31 December historical year was not uniform throughout Western Europe until 1752. The terms anno Domini, Dionysian era, Christian era, vulgar era, and common era were used interchangeably between the Renaissance and the 19th century, at least in Latin. But vulgar era was suppressed in English at the beginning of the twentieth century after vulgar acquired the meaning of "offensively coarse", replacing its original meaning of "common" or "ordinary". Consequently, historians regard all these eras as equal.
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Historians
Bede was the first historian to use a BC year and hence the first to adopt the convention of no year 0 between BC and AD, in his Historia ecclesiastica gentis Anglorum (Ecclesiastical history of the English people, 731). Previous Christian histories used anno mundi (in the year of the world"), or anno Adami ("in the year of Adam", beginning five days later, used by Africanus), or anno Abrahami ("in the year of Abraham", beginning 3,412 years later according to the Septuagint, used by Eusebius), all of which assigned "one" to the year beginning at Creation, or the creation of Adam, or the birth of Abraham, respectively. All began with year 1 because the counting numbers begin with one, not zero. Bede simply continued this earlier tradition relative to the AD era. The inventor of AD, Dionysius Exiguus in 525, did not specify whether he began his count at one or zero (nor did he mention BC).
Bede did not sequentially number any other calendar units (days of the month, weeks of the year, or months of the year—but he was aware of the Jewish days of the week which were numbered beginning with one (except for the seventh which was called the Sabbath) and partially numbered the days of his Christian week accordingly (Lord's day, second day, …, sixth day, Sabbath in English translation).
It is often argued that Bede did not use a year zero because he did not know about the number zero. Although our symbol for zero (0) did not enter Europe until the eleventh century, Bede and Dionysius were well aware of two words for zero—the Latin words nulla and nihil, which in normal speech meant nothing. Nulla was used whenever zero was a member of a series of numbers, whether the other numbers were Roman numerals or Latin words. Dionysius used this Latin zero in the very same table wherein he introduced his anno Domini era, but in a neighboring column—it was the first epact of the 19-year cycle used to calculate Easter (see the nineteen year cycle of Dionysius). Bede continued to use this zero epact in his De temporum ratione (On the reckoning of time, 725), but did not use it between BC and AD. Nihil was used for a remainder of zero when a number was evenly divisible (see arguments two and five in the nineteen year cycle of Dionyius just cited).
In chapter II of book I of Ecclesiastical history, Bede stated that Julius Caesar invaded Britain "in the year 693 after the building of Rome, but the sixtieth year before the incarnation of our Lord", while stating in chapter III, "in the year of Rome 798, Claudius" also invaded Britain and "within a very few days … concluded the war in … the fortysixth [year] from the incarnation of our Lord" [1]. Although both dates are wrong, they are sufficient to conclude that Bede did not include a year zero between BC and AD: 798 − 693 + 1 (because the years are inclusive) = 106, but 60 + 46 = 106, which leaves no room for a year zero. The English term "before Christ" (BC) is not a direct translation of the Latin term "before the incarnation of our Lord" (itself never abbreviated), but is only a rough equivalent: Incarnation means the conception of Christ, which since the 4th century has been celebrated on 25 March, which was nine months before the date on which his birth is celebrated, 25 December. Bede's singular use of 'BC' continued to be used sporadically throughout the Middle Ages (albeit with a correct year). The first extensive use of 'BC' (hundreds of times) occurred in Fasciculus Temporum by Werner Rolevinck in 1474, alongside years of the world (anno mundi).
Astronomers
Astronomers include a year 0 immediately before year 1. The first use of an astronomical year 0 is traditionally attributed to Jacques Cassini in his Tables astronomiques (Astronomical Tables, 1740). His stated reasons for including a year zero were (page 5, translated from French):
The year 0 is that in which one supposes that Jesus Christ was born, which several chronologists mark 1 before the birth of Jesus Christ and which we marked 0, so that the sum of the years before and after Jesus Christ gives the interval which is between these years, and where numbers divisible by 4 mark the leap years as so many before or after Jesus Christ.
But Philippe de La Hire had used a year zero earlier in 1702 in his Tabulæ Astronomicæ (Astronomical Tables) in the form Christum o. ("Christ 0"), without explanation. Both Cassini and La Hire used BC years before their year 0 and AD years thereafter (hence the sequence 1 BC, 0, AD 1). That is why Cassini stated that their sum yielded the interval. For example, 1 + 1 = 2. Beginning in the 19th century, some astronomers began to use negative years before their year 0, while other astronomers continued to use BC years before their year 0. By the mid 20th century, all astronomers were using negative years before year 0 (hence the sequence −1, 0, 1). Thus modern astronomers would state that the years' difference yields the interval, just as it does if the years are both positive or both negative. For example, 1 − (−1) = 2, and 2000 − 1999 = 1. Although 'AD' is omitted from later years, leaving a bare number, a positive sign (+) is sometimes prefixed to the number. Because of possible confusion with the earlier use of an astronomical BC, only in the modern version can it be said that astronomical year 0 equals the historical year 1 BC.
ISO 8601:2004 and ISO 8601:2000, but not ISO 8601:1988, explicitly use astronomical year numbering in their date reference systems. Because they also specify the use of the proleptic Gregorian calendar for all years before 1582, some readers erroneously conclude that a year zero is always included in that calendar, whereas that is unusual. The "basic" format for year 0 is the four-digit form 0000, which equals the historical year 1 BC. Several "expanded" formats are possible: -0000 and +0000, as well as five- and six-digit versions. Earlier years are also negative four-, five- or six-digit years, which have an absolute value one less than the equivalent BC year, hence -0001 = 2 BC. Because only ISO 646 (7-bit ASCII) characters are allowed by ISO 8601, the minus signs are hyphens.
Other year zero traditions
South Asian moon calendars
All eras used with Hindu and Buddhist calendars, such as the Saka era or the Kali Yuga, begin with a year 0 because all of these calendars use elapsed, expired, or complete years, in contrast with most other calendars which use current years. A complete year had not yet elapsed for any date in the year beginning at the epoch, thus that could not be year 1 — instead, it was year 0. This is similar to the Western method of stating a person's age — people do not reach age one until one year has elapsed since birth (but their age during the year beginning at birth is specified in months, not usually as age zero; however if ages were specified in years and months, such a person would be said to be, for example, 0 years and 6 months old).
Mesoamerican Maya historians
Many Maya historians, but not all, assume (or used to assume) that a year 0 exists in the modern calendar and thus specify that the epoch of the Long Count of the Maya calendar occurred in 3113 BC rather than 3114 BC. This would require the sequence 1 BC, 0, AD 1 as in early astronomical years.
Third millennium
Historians note that the 3rd millennium began on 1 January 2001 because they regard the Christian Era as beginning with year 1, whereas many people assumed that it began on 1 January 2000 because that was when the most significant digit of the year changed (1 → 2). So many people confound the "end of the years nineteen hundreds" and the "end of the 20th century", which certainly occured 366 days later.
Astronomical year numbering cannot be used to support year 2000 as the first year of the 3rd millennium because of uncertainty regarding astronomical millennia. Including year 0 in the first positive millennium (0 to 999) while excluding it from the first negative millennium (−1000 to −1) would be inconsistent. But consistency produces unusual results: either year 0 separates the first positive millennium (1 to 1000) from the first negative millennium (−1000 to −1) or it is included in both (−999 to 0 to 999). The consistent solution is that any year zero must be defined "out of centuries". A Year Zero is a Year Zero. It does not belong to any millenia. With regards to the decades like "the 1990s", the year zero, if recognised, is both the first year of the years plus zeros and the first year of the years minus 0s. However, the 200th decade well ends, like the 20th century and the 2nd millennium: 2000, December 31 at midnight.
Media
In the movie Back to the Future Dr. Emmett Brown, the inventor of a time machine, enters the input date of the "birth of Christ" on a keypad as December 25, 0000, implying that he uses the astronomical year numbering (and ignoring questions of whether Jesus was actually born on that year or date).
The fictitious theologian Franz Bibfeldt's most famous work relates to the year 0: a 1927 dissertation submission to the University of Worms entitled "The Problem of the Year 0".
The Zork timeline included with the comedy game Zork Grand Inquisitor features the year 0 GUE with the annotation: "As the year zero begins, people feel fairly confident that something big is about to happen." (As if the people who lived in the BE period were counting down to 0 even before it happened).
Notes
- ^ While it is increasingly common to place AD after a date, by analogy to the use of BC, formal English usage adheres to the traditional practice of placing the abbreviation before the year, as in Latin (e.g., 100 BC, but AD 100).bs:Godina 0
da:0 de:Jahr Null et:0. aasta es:0 eo:Kial Ne Estas Jaro 0 fr:Année zéro ko:0년 hr:Godina 0 it:Anno 0 nl:Nul no:0 sl:0 (leto) fi:Vuosi 0 sv:0 vi:Năm 0 uz:0
