The computus (Latin for 'computation') is a calculation that determines the calendar date of Easter. Easter is traditionally celebrated on the first Sunday after the Paschal full moon, which is the first full moon on or after 21 March (an approximation of the March equinox). Determining this date in advance requires a correlation between the lunar months and the solar year, while also accounting for the month, date, and weekday of the calendar. The calculations produce different results depending on whether the Julian calendar or the Gregorian calendar is used.
In late antiquity, it was feasible for the entire Christian church to receive the date of Easter each year through an annual announcement from the Pope. By the early third century, however, communications had deteriorated to the point that the church put great value in a system that would allow the clergy to independently and consistently determine the date for themselves. Additionally, the church wished to eliminate dependencies on the Hebrew calendar, by deriving Easter directly from the vernal equinox.
In The Reckoning of Time (725), Bede uses computus as a general term for any sort of calculation, although he refers to the Easter cycles of Theophilus as a "Paschal computus." By the end of the 8th century, computus came to refer specifically to the calculation of time.
- "Computus – The calculation to determine the day of Easter" | 2019-04-21 | 10 Upvotes 1 Comments
Freeman John Dyson (15 December 1923 – 28 February 2020) was an English-born American theoretical physicist and mathematician known for his work in quantum electrodynamics, solid-state physics, astronomy and nuclear engineering. He was professor emeritus in the Institute for Advanced Study in Princeton, a member of the Board of Visitors of Ralston College and a member of the Board of Sponsors of the Bulletin of the Atomic Scientists.
Dyson originated several concepts that bear his name, such as Dyson's transform, a fundamental technique in additive number theory, which he developed as part of his proof of Mann's theorem; the Dyson tree, a hypothetical genetically-engineered plant capable of growing in a comet; the Dyson series, a perturbative series where each term is represented by Feynman diagrams; the Dyson sphere, a thought experiment that attempts to explain how a space-faring civilization would meet its energy requirements with a hypothetical megastructure that completely encompasses a star and captures a large percentage of its power output; and Dyson's eternal intelligence, a means by which an immortal society of intelligent beings in an open universe could escape the prospect of the heat death of the universe by extending subjective time to infinity while expending only a finite amount of energy.
Dyson believed global warming is caused merely by increased carbon dioxide but that some of the effects of this are favourable and not taken into account by climate scientists, such as increased agricultural yield. He was skeptical about the simulation models used to predict climate change, arguing that political efforts to reduce causes of climate change distract from other global problems that should take priority. He also signed the World Climate Declaration that there "is no Climate Emergency".
- "Freeman Dyson Has Died" | 2020-02-28 | 91 Upvotes 2 Comments
Gödel's ontological proof is a formal argument by the mathematician Kurt Gödel (1906–1978) for the existence of God. The argument is in a line of development that goes back to Anselm of Canterbury (1033–1109). St. Anselm's ontological argument, in its most succinct form, is as follows: "God, by definition, is that for which no greater can be conceived. God exists in the understanding. If God exists in the understanding, we could imagine Him to be greater by existing in reality. Therefore, God must exist." A more elaborate version was given by Gottfried Leibniz (1646–1716); this is the version that Gödel studied and attempted to clarify with his ontological argument.
Gödel left a fourteen-point outline of his philosophical beliefs in his papers. Points relevant to the ontological proof include
- 4. There are other worlds and rational beings of a different and higher kind.
- 5. The world in which we live is not the only one in which we shall live or have lived.
- 13. There is a scientific (exact) philosophy and theology, which deals with concepts of the highest abstractness; and this is also most highly fruitful for science.
- 14. Religions are, for the most part, bad—but religion is not.
The gates of hell are various places on the surface of the world that have acquired a legendary reputation for being entrances to the underworld. Often they are found in regions of unusual geological activity, particularly volcanic areas, or sometimes at lakes, caves, or mountains.
This is a list of common misconceptions. Each entry is formatted as a correction; the misconceptions themselves are implied rather than stated. These entries are meant to be concise, but more detail can be found in the main subject articles.
This is a partial list of notable people who have been claimed, either by themselves or by their followers, in some way to be the reincarnation or incarnation of Jesus, or the Second Coming of Christ.
- "List of people claimed to be Jesus" | 2018-10-21 | 17 Upvotes 3 Comments
Mandaeism or Mandaeanism (Arabic: مَنْدَائِيَّة, Mandāʾīyah), also known as Sabaeanism (Arabic: صَابِئِيَّة, Ṣābiʾīyah), is a monotheistic and gnostic religion with a strongly dualistic cosmology. Its adherents, the Mandaeans, revere Adam, Abel, Seth, Enos, Noah, Shem, Aram, and especially John the Baptist. The Mandaeans have been counted among the Semites and speak a dialect of Eastern Aramaic known as Mandaic. The name 'Mandaean' is said to come from the Aramaic manda meaning "knowledge", as does Greek gnosis. Within the Middle East, but outside of their community, the Mandaeans are more commonly known as the Ṣubba (singular: Ṣubbī) or Sabians. The term Ṣubba is derived from the Aramaic root related to baptism, the neo-Mandaic is Ṣabi. In Islam, the "Sabians" (Arabic: الصَّابِئُون, aṣ-Ṣābiʾūn) are described several times in the Quran as People of the Book, alongside Jews and Christians. Occasionally, Mandaeans are called "Christians of Saint John".
According to most scholars, Mandaeaism originated sometime in the first three centuries AD, in either southwestern Mesopotamia or the Syro-Palestinian area. However, some scholars take the view that Mandaeanism is older and dates from pre-Christian times.
The religion has been practised primarily around the lower Karun, Euphrates and Tigris and the rivers that surround the Shatt-al-Arab waterway, part of southern Iraq and Khuzestan Province in Iran. There are thought to be between 60,000 and 70,000 Mandaeans worldwide. Until the Iraq War, almost all of them lived in Iraq. Many Mandaean Iraqis have since fled their country because of the turmoil created by the 2003 invasion of Iraq and subsequent occupation by U.S. armed forces, and the related rise in sectarian violence by Muslim extremists. By 2007, the population of Mandaeans in Iraq had fallen to approximately 5,000.
The Mandaeans have remained separate and intensely private. Reports of them and of their religion have come primarily from outsiders: particularly from Julius Heinrich Petermann, an Orientalist as well as from Nicolas Siouffi, a Syrian Christian who was the French vice-consul in Mosul in 1887, and British cultural anthropologist Lady E. S. Drower. There is an early if highly prejudiced account by the French traveller Jean-Baptiste Tavernier from the 1650s.
- "Mandaeism" | 2018-05-21 | 83 Upvotes 41 Comments
The River Thames frost fairs were held on the tideway of the River Thames in London, England in some winters, starting at least as early as the late 7th century all the way until the early 19th century. Most were held between the early 17th and early 19th centuries during the period known as the Little Ice Age, when the river froze over most frequently. During that time the British winter was more severe than it is now, and the river was wider and slower, further impeded by the medieval Old London Bridge.
Even at its peak, in the mid-17th century, the Thames in London froze less often than modern legend sometimes suggests, never exceeding about one year in ten except for four winters between 1649 and 1666. From 1400 until the removal of the medieval London Bridge in 1835, there were 24 winters in which the Thames was recorded to have frozen over at London; if "more or less frozen over" years (in parentheses) are included, the number is 26: 1408, 1435, 1506, 1514, 1537, 1565, 1595, 1608, 1621, 1635, 1649, 1655, 1663, 1666, 1677, 1684, 1695, 1709, 1716, 1740, (1768), 1776, (1785), 1788, 1795, and 1814. Of the 24, the numbers in each century were: 15th two, 16th five, 17th ten, 18th six, 19th one. The Thames freezes over more often upstream, beyond the reach of the tide, especially above the weirs, of which Teddington Lock is the lowest. The last great freeze of the higher Thames was in 1962–63.
Frost fairs were a rare event even in the coldest parts of the Little Ice Age. Some of the recorded frost fairs were in 695, 1608, 1683-4, 1716, 1739–40, 1789, and 1814. Recreational cold weather winter events were far more common elsewhere in Europe, for example in the Netherlands. These events in other countries as well as the winter festivals and carnivals around the world in present times can also be considered frost fairs. However, very few of them have actually used that title.
During the Great Frost of 1683–84, the severest frost recorded in England, the Thames was completely frozen for two months, with the ice reaching a thickness of 11 inches (28 cm) in London. Solid ice was reported extending for miles off the coasts of the southern North Sea (England, France and the Low Countries), causing severe problems for shipping and preventing the use of many harbours.
- "River Thames Frost Fairs" | 2020-05-18 | 57 Upvotes 10 Comments
Sir Douglas Ralph Nicholls, (9 December 1906 – 4 June 1988) was a prominent Aboriginal Australian from the Yorta Yorta people. He was a professional athlete, Churches of Christ pastor and church planter, ceremonial officer and a pioneering campaigner for reconciliation.
Nicholls was the first Aboriginal Australian to be knighted when he was appointed Knight Bachelor in 1972 (he was subsequently appointed a Knight Commander of the Royal Victorian Order in 1977). He was also the first — and to date the only — Indigenous Australian to be appointed to vice-regal office, serving as Governor of South Australia from 1 December 1976 until his resignation on 30 April 1977 due to poor health.
- "Sir Douglas Nicholls" | 2021-04-29 | 55 Upvotes 17 Comments
The Public Universal Friend (born Jemima Wilkinson; November 29, 1752 – July 1, 1819) was an American preacher born in Cumberland, Rhode Island, to Quaker parents. After suffering a severe illness in 1776, the Friend claimed to have died and been reanimated as a genderless evangelist named the Public Universal Friend, and afterward shunned both birth name and gendered pronouns. In androgynous clothes, the Friend preached throughout the northeastern United States, attracting many followers who became the Society of Universal Friends.
The Public Universal Friend's theology was broadly similar to that of most Quakers. The Friend stressed free will, opposed slavery, and supported sexual abstinence. The most committed members of the Society of Universal Friends were a group of unmarried women who took leading roles in their households and community. In the 1790s, members of the Society acquired land in Western New York where they formed the township of Jerusalem near Penn Yan, New York. The Society of Universal Friends ceased to exist by the 1860s. Many writers have portrayed the Friend as a woman, and either a manipulative fraudster, or a pioneer for women's rights; others have viewed the preacher as transgender or non-binary and a figure in trans history.