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🔗 Physics 🔗 Astronomy

In astrophysics and physical cosmology, Olbers' paradox, named after the German astronomer Heinrich Wilhelm Olbers (1758–1840), also known as the "dark night sky paradox", is the argument that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. In the hypothetical case that the universe is static, homogeneous at a large scale, and populated by an infinite number of stars, any line of sight from Earth must end at the surface of a star and hence the night sky should be completely illuminated and very bright. This contradicts the observed darkness and non-uniformity of the night.

The darkness of the night sky is one of the pieces of evidence for a dynamic universe, such as the Big Bang model. That model explains the observed non-uniformity of brightness by invoking spacetime's expansion, which lengthens the light originating from the Big Bang to microwave levels via a process known as redshift; this microwave radiation background has wavelengths much longer than those of visible light, and so appears dark to the naked eye. Other explanations for the paradox have been offered, but none have wide acceptance in cosmology.

🔗 Computing

Constraint programming (CP) is a paradigm for solving combinatorial problems that draws on a wide range of techniques from artificial intelligence, computer science, and operations research. In constraint programming, users declaratively state the constraints on the feasible solutions for a set of decision variables. Constraints differ from the common primitives of imperative programming languages in that they do not specify a step or sequence of steps to execute, but rather the properties of a solution to be found. In addition to constraints, users also need to specify a method to solve these constraints. This typically draws upon standard methods like chronological backtracking and constraint propagation, but may use customized code like a problem specific branching heuristic.

Constraint programming takes its root from and can be expressed in the form of constraint logic programming, which embeds constraints into a logic program. This variant of logic programming is due to Jaffar and Lassez, who extended in 1987 a specific class of constraints that were introduced in Prolog II. The first implementations of constraint logic programming were Prolog III, CLP(R), and CHIP.

Instead of logic programming, constraints can be mixed with functional programming, term rewriting, and imperative languages. Programming languages with built-in support for constraints include Oz (functional programming) and Kaleidoscope (imperative programming). Mostly, constraints are implemented in imperative languages via constraint solving toolkits, which are separate libraries for an existing imperative language.

🔗 Climate change 🔗 Environment 🔗 Automobiles

Rolling coal (also spelled rollin' coal) is the practice of modifying a diesel engine to emit large amounts of black or grey sooty exhaust fumes—diesel fuel that has not undergone complete combustion.

Rolling coal is a form of anti-environmentalism. Such modifications may include the intentional removal of the particulate filter. Practitioners often additionally modify their vehicles by installing smoke switches, large exhausts, and smoke stacks. Modifications to a vehicle to enable rolling coal may cost from US$200 to US$5,000.

🔗 Lists 🔗 Anthroponymy

This list of eponymous laws provides links to articles on laws, principles, adages, and other succinct observations or predictions named after a person. In some cases the person named has coined the law – such as Parkinson's law. In others, the work or publications of the individual have led to the law being so named – as is the case with Moore's law. There are also laws ascribed to individuals by others, such as Murphy's law; or given eponymous names despite the absence of the named person.

🔗 Canada 🔗 Finance & Investment 🔗 Marketing & Advertising 🔗 Numismatics 🔗 Automobiles 🔗 Retailing

Canadian Tire money, officially Canadian Tire 'money' or CTM, is a loyalty program operated by the Canadian retail chain Canadian Tire Corporation (CTC). It consists of both paper coupons introduced in 1958 and used in Canadian Tire stores as scrip, and since 2012 in a digital form introduced as Canadian Tire Money Advantage, rebranded in 2018 as Triangle Rewards. Both forms of the loyalty program remain current as of December 2022. Canadian Tire Money has been noted as the most successful loyalty program in Canadian retail history.

Canadian Tire Money is denominated in Canadian dollars. It is earned based on the pre-tax amount of a purchase, excluding labour and shop supplies costs. The initial rate earned was 5% of the eligible purchase price, but it was lowered to 3%, then to 1.4% and now is 0.4%.

When used to pay for merchandise, CTM is considered to be a cash equivalent and may be used to pay for any part of a purchase, including sales taxes. CTM cannot be exchanged for real Canadian currency.

🔗 Ancient Near East 🔗 Bible 🔗 Iraq 🔗 Archaeology 🔗 Cities

Ur was an important Sumerian city-state in ancient Mesopotamia, located at the site of modern Tell el-Muqayyar (Arabic: تل ٱلْمُقَيَّر) in south Iraq's Dhi Qar Governorate. Although Ur was once a coastal city near the mouth of the Euphrates on the Persian Gulf, the coastline has shifted and the city is now well inland, on the south bank of the Euphrates, 16 kilometres (9.9 miles) from Nasiriyah in modern-day Iraq. The city dates from the Ubaid period circa 3800 BC, and is recorded in written history as a city-state from the 26th century BC, its first recorded king being Mesannepada.

The city's patron deity was Nanna (in Akkadian, Sin), the Sumerian and Akkadian moon god, and the name of the city is in origin derived from the god's name, UNUG^KI, literally "the abode (UNUG) of Nanna". The site is marked by the partially restored ruins of the Ziggurat of Ur, which contained the shrine of Nanna, excavated in the 1930s. The temple was built in the 21st century BC (short chronology), during the reign of Ur-Nammu and was reconstructed in the 6th century BC by Nabonidus, the last king of Babylon. The ruins cover an area of 1,200 metres (3,900 ft) northwest to southeast by 800 metres (2,600 ft) northeast to southwest and rise up to about 20 metres (66 ft) above the present plain level.

🔗 Secret Societies

The backbone cabal was an informal organization of large-site news server administrators of the worldwide distributed newsgroup-based discussion system Usenet. It existed from about 1983 at least into the 2000s.

The cabal was created in an effort to facilitate reliable propagation of new Usenet posts. While in the 1970s and 1980s many news servers only operated during night time to save on the cost of long distance communication, servers of the backbone cabal were available 24 hours a day. The administrators of these servers gained sufficient influence in the otherwise anarchic Usenet community to be able to push through controversial changes, for instance the Great Renaming of Usenet newsgroups during 1987.

🔗 United States/U.S. Government 🔗 United States 🔗 Terrorism

The 1983 U.S. Senate bombing was a bomb explosion at the United States Senate on November 7, 1983, motivated by United States military involvement in Lebanon and Grenada. The attack led to heightened security in the DC metropolitan area, and the inaccessibility of certain parts of the Senate Building. Six members of the radical left-wing Resistance Conspiracy were arrested in May 1988 and charged with the bombing, as well as related bombings of Fort McNair and the Washington Navy Yard which occurred April 25, 1983, and April 20, 1984, respectively.

🔗 Russia 🔗 Russia/mass media in Russia 🔗 Internet culture 🔗 Russia/language and literature of Russia

Padonkaffsky jargon (Russian: язык падонкафф, yazyk padonkaff) or Olbanian (олбанский, olbanskiy) is a cant language developed by a subculture of Runet called padonki (Russian: падонки). It started as an Internet slang language originally used in the Russian Internet community. It is comparable to the English-based Leet. Padonkaffsky jargon became so popular that the former President of Russia Dmitry Medvedev jokingly suggested that Olbanian be taught in schools.

🔗 Engineering

Ephemeralization, a term coined by R. Buckminster Fuller in 1938, is the ability of technological advancement to do "more and more with less and less until eventually you can do everything with nothing," that is, an accelerating increase in the efficiency of achieving the same or more output (products, services, information, etc.) while requiring less input (effort, time, resources, etc.). Fuller's vision was that ephemeralization will result in ever-increasing standards of living for an ever-growing population despite finite resources. The concept has been embraced by those who argue against Malthusian philosophy. The subsequently coined economics term "dematerialization" refers to essentially the same concept as also does eco-economic decoupling.