In 2024, a proposal was published to add an eighth day named "Earthsday" to the week between Wednesday and Thursday so that the Gregorian calendar would have eight columns rather than seven. Its primary objective is to maintain greater numbers of human-performed jobs as the growth of automation and artificial intelligence increasingly displace human workers. An even number of days in the week would help societies more smoothly and gradually decrease "full-time" working hours per person. The complete proposal is set forth in the book, "The Earthsday Calendar: Bringing an 8-day Week to the Modern World", by Mark Lee Driskill, ISBN: 978-1-963501-21-6
Some historical calendars had "weeks" consisting of eight days.
In the Burmese version of Theravada Buddhism, the week has eight days. Wednesday is divided into Wednesday proper (midnight to noon) and Rahu (noon to midnight). Each day is associated with a compass direction, a planet, and a totem animal.
The ancient Etruscans developed an eight-day market week known as the nundinum around the 8th or 7th century BC. This was passed on to the Romans no later than the 6th century BC. As Rome expanded, it encountered the seven-day week and for a time attempted to include both. The popularity of the seven-day rhythm won, and the eight-day week disappeared.
The cycle of seven days – named for the sun, the moon, and the five planets visible to the naked eye – was already customary in the time of Justin Martyr, who wrote of the Christians meeting on the Day of the Sun (Sunday). [1]
Emperor Constantine eventually established the seven-day week in the Roman calendar in AD 321. [2]
The Celts used periods of darkness such as night and winter to begin their calculations of time. This meant that the first period of time in a "week" was a night, followed by a day. Further, they also counted the ending night period, giving rise to periods of time with more nights than days. In Old Irish, the term nómad is used to signify a number of days. The usage of the term varies and there are different theories about the length of time involved, but they all involve nine periods of some kind, e.g. nine days & nights; 9 × 8 hours = 72 hours = 3 days & nights; 9 × 9 hours ~ 3½ days; 9 × 12 hours = 4½ days. [3] [4] Joseph Loth noted the frequency of the expression co cend nomaide (“to the end of a nómad”) in the literature—sometimes replaced by nóilaíthe (“nine days”)—and how the division fitted neatly into a sidereal month of 27 nights. [4] In Welsh, the word for "week" is wythnos which literally means "eight-nights" since it was historically considered that a week started and ended with a period of night bracketing seven days. Similarly the word for "fortnight", pythefnos, literally means "fifteen-nights". [5] [6] The Irish word for "fortnight", coicís , also relates to the number fifteen.
A day is the time period of a full rotation of the Earth with respect to the Sun. On average, this is 24 hours. As a day passes at a given location it experiences morning, noon, afternoon, evening, and night. This daily cycle drives circadian rhythms in many organisms, which are vital to many life processes.
An hour is a unit of time historically reckoned as 1⁄24 of a day and defined contemporarily as exactly 3,600 seconds (SI). There are 60 minutes in an hour, and 24 hours in a day.
A week is a unit of time equal to seven days. It is the standard time period used for short cycles of days in most parts of the world. The days are often used to indicate common work days and rest days, as well as days of worship. Weeks are often mapped against yearly calendars, but are typically not the basis for them, as weeks are not based on astronomy.
Sunday is the day of the week between Saturday and Monday. Sunday is a day of rest in most Western countries and a part of the weekend. In some Middle Eastern countries, Sunday is a weekday.
Wednesday is the day of the week between Tuesday and Thursday. According to international standard ISO 8601, it is the third day of the week. In countries which have Friday as their holiday, Wednesday is the fifth day of the week. In countries which use the Sunday-first convention, and in both the Islamic and Jewish calendars, Wednesday is the fourth day of the week.
A fortnight is a unit of time equal to 14 days. The word derives from the Old English term fēowertīene niht, meaning "fourteen nights".
In the practice of Christianity, canonical hours mark the divisions of the day in terms of fixed times of prayer at regular intervals. A book of hours, chiefly a breviary, normally contains a version of, or selection from, such prayers.
Noon is 12 o'clock in the daytime. It is written as 12 noon, 12:00 m., 12 p.m., 12 pm, or 12:00 or 1200 . Solar noon is the time when the Sun appears to contact the local celestial meridian. This is when the Sun reaches its apparent highest point in the sky, at 12 noon apparent solar time and can be observed using a sundial. The local or clock time of solar noon depends on the date, longitude, and time zone, with Daylight Saving Time tending to place solar noon closer to 1:00pm.
The 12-hour clock is a time convention in which the 24 hours of the day are divided into two periods: a.m. and p.m.. Each period consists of 12 hours numbered: 12, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 and 11. The 12-hour clock has been developed since the second millennium BC and reached its modern form in the 16th century.
Midnight sun, also known as polar day, is a natural phenomenon that occurs in the summer months in places north of the Arctic Circle or south of the Antarctic Circle, when the Sun remains visible at the local midnight. When midnight sun is seen in the Arctic, the Sun appears to move from left to right. In Antarctica, the equivalent apparent motion is from right to left. This occurs at latitudes ranging from approximately 65°44' to exactly 90° north or south, and does not stop exactly at the Arctic Circle or the Antarctic Circle, due to refraction.
Matins is a canonical hour in Christian liturgy, originally sung during the darkness of early morning.
The Celtic calendar is a compilation of pre-Christian Celtic systems of timekeeping, including the Gaulish Coligny calendar, used by Celtic countries to define the beginning and length of the day, the week, the month, the seasons, quarter days, and festivals.
Birkat Hachama refers to a rare Jewish blessing that is recited to the Creator, thanking God for creating the sun. The blessing is recited when the Sun completes its cycle every 28 years on a Tuesday at sundown. Jewish tradition says that when the Sun completes this cycle, it has returned to its position when the world was created. Because the blessing needs to be said when the Sun is visible, the blessing is postponed to the following day, on Wednesday morning.
In many languages, the names given to the seven days of the week are derived from the names of the classical planets in Hellenistic astronomy, which were in turn named after contemporary deities, a system introduced by the Sumerians and later adopted by the Babylonians from whom the Roman Empire adopted the system during late antiquity. In some other languages, the days are named after corresponding deities of the regional culture, beginning either with Sunday or with Monday. The seven-day week was adopted in early Christianity from the Hebrew calendar, and gradually replaced the Roman internundinum.
In modern usage, civil time refers to statutory time as designated by civilian authorities. Modern civil time is generally national standard time in a time zone at a fixed offset from Coordinated Universal Time (UTC), possibly adjusted by daylight saving time during part of the year. UTC is calculated by reference to atomic clocks and was adopted in 1972. Older systems use telescope observations.
The Copts, who belong mostly to the Coptic Orthodox Church, observe fasting periods according to the Coptic calendar. In Coptic Orthodox Christianity, fasting is defined as going without water and food from midnight to sunset; after that time, the consumption of water and one vegetarian meal is permitted. The fasting periods of Coptic Christians are exceeded by no other Christian denomination except the Orthodox Tewahedo. Out of the 365 days of the year, Copts often fast between 210 and 240 days. This means that Copts abstain from all animal products for up to two-thirds of each year. Coptic Orthodox fasts have evolved over time to become more lengthy and severe. A lifestyle involving such fasts may have contributed to the pacifist mindset of the Coptic people for centuries. Married couples refrain from sexual relations during Lent "to give themselves time for fasting and prayer".
The Akan people appear to have used a traditional system of timekeeping based on a six-day week. The Gregorian seven-day week is known as nnawɔtwe (eight-days). The combination of these two system resulted in periods of 40 days, known as adaduanan.
In Roman timekeeping, a day was divided into periods according to the available technology. Initially, the day was divided into two parts: the ante meridiem and the post meridiem. With the introduction of the Greek sundial to Rome from the Samnites circa 293 BC, the period of the natural day from sunrise to sunset was divided into twelve hours.
The shift plan, rota or roster is the central component of a shift schedule in shift work. The schedule includes considerations of shift overlap, shift change times and alignment with the clock, vacation, training, shift differentials, holidays, etc. The shift plan determines the sequence of work (W) and free (F) days within a shift system.
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