Hebrew Calendar Yahweh’s Time Clock Given to Moses in Genesis
Hebrew Calendar Yahweh’s Time Clock Given to Moses
The Hebrew or Jewish calendar (הַלּוּחַ הָעִבְרִי, Ha-Luah ha-Ivri) is a lunisolar calendar used today predominantly for Jewish religious observances. It determines the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates to commemorate the death of a relative), and daily Psalm readings, among many ceremonial uses. In Israel, it is used for religious purposes, provides a time frame for agriculture and is an official calendar for civil purposes.
The Hebrew lunar year is about eleven days shorter than the solar year and uses the 19-year Metonic cycle to bring it into line with the solar year, with the addition of an intercalary month every two or three years, for a total of seven times per 19 years. Even with this intercalation, the average Hebrew calendar year is longer by about 6 minutes and 40 seconds than the current mean tropical year, so that every 216 years the Hebrew calendar will fall a day behind the current mean tropical year; and about every 231 years it will fall a day behind the mean Gregorian calendar year.
The era used since the Middle Ages is the Anno Mundi epoch (Latin for “in the year of the world”; Hebrew: לבריאת העולם, “from the creation of the world”). As with Anno Domini (A.D. or AD), the words or abbreviation for Anno Mundi (A.M. or AM) for the era should properly precede the date rather than follow it.
AM 5777 began at sunset on 2 October 2016 and will end at sunset on 20 September 2017.
Day and hours
The Jewish day is of no fixed length. The Jewish day is modeled on the reference to “…there was evening and there was morning…” in the creation account in the first chapter of Genesis. Based on the classic rabbinic interpretation of this text, a day in the rabbinic Hebrew calendar runs from sunset (start of “the evening”) to the next sunset. In most populated parts of the world this is always approximately 24 standard hours, but, depending on the season of the year, it can be slightly less or slightly more. Halachically, a day ends and a new one starts when three stars are visible in the sky. The time between true sunset and the time when the three stars are visible (known as ‘tzait ha’kochavim’) is known as ‘bein hashmashot’, and there are differences of opinion as to which day it falls into for some uses. This may be relevant, for example, in determining the date of birth of a child born during that gap.
There is no clock in the Jewish scheme, so that the local civil clock is used. Though the civil clock, including the one in use in Israel, incorporates local adoptions of various conventions such as time zones, standard times and daylight saving, these have no place in the Jewish scheme. The civil clock is used only as a reference point – in expressions such as: “Shabbat starts at …”. The steady progression of sunset around the world and seasonal changes results in gradual civil time changes from one day to the next based on observable astronomical phenomena (the sunset) and not on man-made laws and conventions.
In Judaism, an hour is defined as 1/12 of the time from sunrise to sunset, so, during the winter, an hour can be much less than 60 minutes, and during the summer, it can be much more than 60 minutes. This proportional hour is known as a sha’ah z’manit (lit. a timely hour). A Jewish hour is divided into 1080 halakim (singular: helek) or parts. A part is 3⅓ seconds or 1/18 minute. The ultimate ancestor of the helek was a small Babylonian time period called a barleycorn, itself equal to 1/72 of a Babylonian time degree (1° of celestial rotation). These measures are not generally used for everyday purposes.
Instead of the international date line convention, there are varying opinions as to where the day changes. One opinion uses the antimeridian of Jerusalem. (Jerusalem is 35°13′ east of the prime meridian, so the antimeridian is at 144°47′ W, passing through eastern Alaska.) Other opinions exist as well. (See International date line in Judaism.)
While calculations of days, months and years are based on fixed hours equal to 1/24 of a day, the beginning of each halachic day is based on the local time of sunset. The end of the Shabbat and other Jewish holidays is based on nightfall (Tzeth haKochabim) which occurs some amount of time, typically 42 to 72 minutes, after sunset. According to Maimonides, nightfall occurs when three medium-sized stars become visible after sunset. By the 17th century, this had become three-second-magnitude stars. The modern definition is when the center of the sun is 7° below the geometric (airless) horizon, somewhat later than civil twilight at 6°. The beginning of the daytime portion of each day is determined both by dawn and sunrise. Most halachic times are based on some combination of these four times and vary from day to day throughout the year and also vary significantly depending on location. The daytime hours are often divided into Sha’oth Zemaniyoth or “Halachic hours” by taking the time between sunrise and sunset or between dawn and nightfall and dividing it into 12 equal hours. The nighttime hours are similarly divided into 12 equal portions, albeit a different amount of time than the “hours” of the daytime. The earliest and latest times for Jewish services, the latest time to eat chametz on the day before Passover and many other rules are based on Sha’oth Zemaniyoth. For convenience, the modern day using Sha’oth Zemaniyoth is often discussed as if sunset were at 6:00 pm, sunrise at 6:00 am and each hour were equal to a fixed hour. For example, halachic noon may be after 1:00 pm in some areas during daylight saving time. Within the Mishnah, however, the numbering of the hours starts with the “first” hour after the start of the day.
Shavua [שבוע] is a weekly cycle of seven days, mirroring the seven-day period of the Book of Genesis in which the world is created. The names for the days of the week, like those in the creation account, are simply the day number within the week, with Shabbat being the seventh day. Each day of the week runs from sunset to the following sunset and is figured locally.
Names of weekdays
The Hebrew calendar follows a seven-day weekly cycle, which runs concurrently with but independently of the monthly and annual cycles. The names for the days of the week are simply the day number within the week. In Hebrew, these names may be abbreviated using the numerical value of the Hebrew letters, for example יום א׳ (Day 1, or Yom Rishon (יום ראשון)):
- Yom Rishon – יום ראשון (abbreviated יום א׳), meaning “first day” [corresponds to Sunday] (starting at preceding sunset of Saturday)
- Yom Sheni – יום שני (abbr. יום ב׳) meaning “second day” [corresponds to Monday]
- Yom Shlishi – יום שלישי (abbr. יום ג׳) meaning “third day” [corresponds to Tuesday]
- Yom Reviʻi – יום רביעי (abbr. יום ד׳) meaning “fourth day” [corresponds to Wednesday]
- Yom Chamishi – יום חמישי (abbr. יום ה׳) = “fifth day” [corresponds to Thursday]
- Yom Shishi – יום ששי (abbr. יום ו׳) meaning “sixth day” [corresponds to Friday]
- Yom Shabbat – יום שבת (abbr. יום ש׳), or more usually Shabbat – שבת meaning “rest day” [corresponds to Saturday]
Also known as Yom Shabbat Kodesh יום שבת קודש (“holy rest day”).
The names of the days of the week are modeled on the seven days mentioned in the creation story. For example, Genesis 1:5 “… And there was evening and there was morning, one day”. One day (יוֹם אֶחָד) in Genesis 1:15 is translated in JPS as first day, and in some other contexts (including KJV) as day one. In subsequent verses, the Hebrew refers to the days using ordinal numbers, e.g., ‘second day’, ‘third day’, and so forth, but with the sixth and seventh days the Hebrew includes the definite article (“the”).
Days of week of holidays
The period from 1 Adar (or Adar II, in leap years) to 29 Marcheshvan contains all of the festivals specified in the Bible – Purim (14 Adar), Pesach (15 Nisan), Shavuot (6 Sivan), Rosh Hashanah (1 Tishrei), Yom Kippur (10 Tishrei), Sukkot (15 Tishrei), and Shemini Atzeret (22 Tishrei). This period is fixed, during which no adjustments are made.
|10 Tevet||Tu Bishvat|
|Thu||Sat||Sun||Sun*||Mon||Wed||Sun or Mon||Sun or Tue||Sat or Mon|
|Sun||Tue||Wed||Tue||Thu||Sat||Wed or Thu||Wed, Thu, or Fri||Tue, Wed, or Thu|
|Tue||Thu||Fri||Thu||Sat||Mon||Fri or Sat||Fri or Sun||Thu or Sat|
|*Postponed from Shabbat|
There are additional rules in the Hebrew calendar to prevent certain holidays from falling on certain days of the week. (See Rosh Hashanah postponement rules, below.) These rules are implemented by adding an extra day to Marcheshvan (making it 30 days long) or by removing one day from Kislev (making it 29 days long). Accordingly, a common Hebrew calendar year can have a length of 353, 354 or 355 days, while a leap Hebrew calendar year can have a length of 383, 384 or 385 days.
The Hebrew calendar is a lunisolar calendar, meaning that months are based on lunar months, but years are based on solar years. The calendar year features twelve lunar months of twenty-nine or thirty days, with an intercalary lunar month added periodically to synchronize the twelve lunar cycles with the longer solar year. (These extra months are added seven times every nineteen years. See Leap months, below.) The beginning of each Jewish lunar month is based on the appearance of the new moon. Although originally the new lunar crescent had to be observed and certified by witnesses, the moment of the true new moon is now approximated arithmetically as the molad, which is the mean new moon to a precision of one part.
The mean period of the lunar month (precisely, the synodic month) is very close to 29.5 days. Accordingly, the basic Hebrew calendar year is one of twelve lunar months alternating between 29 and 30 days:
|8||Marcheshvan (or Cheshvan)||29/30|
|Total||353, 354 or 355|
In leap years (such as 5774) an additional month, Adar I (30 days) is added after Shevat, while the regular Adar is referred to as “Adar II.”
The insertion of the leap month mentioned above is based on the requirement that Passover—the festival celebrating the Exodus from Egypt, which took place in the spring—always occurs in the [northern hemisphere’s] spring season. Since the adoption of a fixed calendar, intercalations in the Hebrew calendar have been assigned to fixed points in a 19-year cycle. Prior to this, the intercalation was determined empirically:
The year may be intercalated on three grounds: ‘aviv [i.e.the ripeness of barley], fruits of trees, and the equinox. On two of these grounds it should be intercalated, but not on one of them alone.
Hebrew Calendar Yahweh’s Time Clock Given to Moses