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🔗 Astronomy 🔗 Astronomy/Astronomical objects

Wolf 359 is a red dwarf star located in the constellation Leo, near the ecliptic. At a distance of approximately 7.9 light years from Earth, it has an apparent magnitude of 13.54 and can only be seen with a large telescope. Wolf 359 is one of the nearest stars to the Sun; only the Alpha Centauri system (including Proxima Centauri), Barnard's Star and the brown dwarfs Luhman 16 and WISE 0855−0714 are known to be closer. Its proximity to Earth has led to its mention in several works of fiction.

Wolf 359 is one of the faintest and lowest-mass stars known. At the light-emitting layer called the photosphere, it has a temperature of about 2,800 K, which is low enough for chemical compounds to form and survive. The absorption lines of compounds such as water and titanium(II) oxide have been observed in the spectrum. The surface has a magnetic field that is stronger than the average magnetic field on the Sun. As a result of magnetic activity caused by convection, Wolf 359 is a flare star that can undergo sudden increases in luminosity for several minutes. These flares emit strong bursts of X-ray and gamma ray radiation that have been observed by space telescopes. Wolf 359 is a relatively young star with an age of less than a billion years. Two planetary companions are suspected but as yet no debris disks have been unmasked.

🔗 United States 🔗 Film 🔗 Library of Congress 🔗 Film/American cinema 🔗 Film/Silent films 🔗 Film/Documentary films 🔗 United States/Film - American cinema

A Trip Down Market Street is a 13-minute actuality film recorded by placing a movie camera on the front of a cable car as it traveled down San Francisco’s Market Street. The film shows many details of daily life in a major early 20th century American city, including the transportation, fashions and architecture of the era. The film begins at 8th Street and continues eastward to the cable car turntable, at The Embarcadero, in front of the Ferry Building. Landmarks passed in the latter part of the first half include the Call Building (then San Francisco's tallest) and the Palace Hotel (both on the right; Lotta's Fountain is on the left between the two but is in the shade). The film was produced by the four Miles brothers: Harry, Herbert, Earle and Joe. It is notable for capturing San Francisco four days before the 1906 San Francisco earthquake, which started on the morning of Wednesday, April 18, 1906.

The Miles brothers had been producing films in New York including films shot in San Francisco. In September 1905 they shot the fight between Oscar "Battling" Nelson and Jimmy Britt in Colma, California, just south of San Francisco city limits. The Miles brothers established a studio at 1139 Market Street in San Francisco in early 1906. They shot a railroad descent down Mount Tamalpais as well as the Market Street film. On April 17, Harry and Joe Miles boarded a train for New York, taking the two films with them, but they heard about the earthquake and sent the films to New York while they boarded another train headed back to San Francisco. The Turk Street house of Earle Miles survived the earthquake and subsequent catastrophic fire but the studio did not. The Miles brothers based their business out of Earle's home, and shot more film of post-earthquake scenes; some of this footage, including that of a second trip down a now devastated Market Street, reemerged in 2016. It is likely that the Market Street film survives today because it was sent away before the fire.

Several 35mm prints exist with slight changes in footage. Copies are held at the Library of Congress and the Prelinger Archives. A digital version is viewable online at Internet Archive, YouTube and Wikimedia Commons. In 2010, the film was selected for preservation in the National Film Registry by the Library of Congress.

🔗 Computing 🔗 Computing/Software 🔗 Computing/Computer science 🔗 Cryptography 🔗 Cryptography/Computer science

In cryptography and computer science, a hash tree or Merkle tree is a tree in which every leaf node is labelled with the cryptographic hash of a data block, and every non-leaf node is labelled with the cryptographic hash of the labels of its child nodes. Hash trees allow efficient and secure verification of the contents of large data structures. Hash trees are a generalization of hash lists and hash chains.

Demonstrating that a leaf node is a part of a given binary hash tree requires computing a number of hashes proportional to the logarithm of the number of leaf nodes of the tree; this contrasts with hash lists, where the number is proportional to the number of leaf nodes itself.

The concept of hash trees is named after Ralph Merkle, who patented it in 1979.

🔗 United States 🔗 Film 🔗 Library of Congress 🔗 Film/American cinema 🔗 United States/Film - American cinema 🔗 Science Fiction 🔗 Transhumanism 🔗 Guild of Copy Editors 🔗 Film/Core 🔗 Film/British cinema 🔗 Hertfordshire

2001: A Space Odyssey is a 1968 epic science fiction film produced and directed by Stanley Kubrick. The screenplay was written by Kubrick and science fiction author Arthur C. Clarke, and was inspired by Clarke's 1951 short story "The Sentinel" and other short stories by Clarke. Clarke also published a novelisation of the film, in part written concurrently with the screenplay, after the film's release. The film stars Keir Dullea, Gary Lockwood, William Sylvester, and Douglas Rain, and follows a voyage by astronauts, scientists and the sentient supercomputer HAL to Jupiter to investigate an alien monolith.

The film is noted for its scientifically accurate depiction of space flight, pioneering special effects, and ambiguous imagery. Kubrick avoided conventional cinematic and narrative techniques; dialogue is used sparingly, and there are long sequences accompanied only by music. The soundtrack incorporates numerous works of classical music, by composers including Richard Strauss, Johann Strauss II, Aram Khachaturian, and György Ligeti.

The film received diverse critical responses, ranging from those who saw it as darkly apocalyptic to those who saw it as an optimistic reappraisal of the hopes of humanity. Critics noted its exploration of themes such as human evolution, technology, artificial intelligence, and the possibility of extraterrestrial life. It was nominated for four Academy Awards, winning Kubrick the award for his direction of the visual effects. The film is now widely regarded as one of the greatest and most influential films ever made. In 1991, it was selected by the United States Library of Congress for preservation in the National Film Registry. In 2022, 2001: A Space Odyssey placed in the top ten of Sight & Sound's decennial critics' poll, and topped their directors' poll.

🔗 Physics 🔗 Astronomy

Rømer's determination of the speed of light was the demonstration in 1676 that light has a finite speed and so does not travel instantaneously. The discovery is usually attributed to Danish astronomer Ole Rømer, who was working at the Royal Observatory in Paris at the time.

By timing the eclipses of the Jovian moon Io, Rømer estimated that light would take about 22 minutes to travel a distance equal to the diameter of Earth's orbit around the Sun. This would give light a velocity of about 220,000 kilometres per second, about 26% lower than the true value of 299,792 km/s.

Rømer's theory was controversial at the time that he announced it and he never convinced the director of the Paris Observatory, Giovanni Domenico Cassini, to fully accept it. However, it quickly gained support among other natural philosophers of the period such as Christiaan Huygens and Isaac Newton. It was finally confirmed nearly two decades after Rømer's death, with the explanation in 1729 of stellar aberration by the English astronomer James Bradley.

In computer science and mathematics, a full employment theorem is a term used, often humorously, to refer to a theorem which states that no algorithm can optimally perform a particular task done by some class of professionals. The name arises because such a theorem ensures that there is endless scope to keep discovering new techniques to improve the way at least some specific task is done.

For example, the full employment theorem for compiler writers states that there is no such thing as a provably perfect size-optimizing compiler, as such a proof for the compiler would have to detect non-terminating computations and reduce them to a one-instruction infinite loop. Thus, the existence of a provably perfect size-optimizing compiler would imply a solution to the halting problem, which cannot exist. This also implies that there may always be a better compiler since the proof that one has the best compiler cannot exist. Therefore, compiler writers will always be able to speculate that they have something to improve. A similar example in practical computer science is the idea of no free lunch in search and optimization, which states that no efficient general-purpose solver can exist, and hence there will always be some particular problem whose best known solution might be improved.

Similarly, Gödel's incompleteness theorems have been called full employment theorems for mathematicians. In theoretical computer science this field of study is known as Kolmogorov complexity, or the smallest program which outputs a given string.

Tasks such as virus writing and detection, and spam filtering and filter-breaking are also subject to Rice's theorem.

🔗 United States 🔗 Computing 🔗 Computing/Computer hardware 🔗 Plan 9

The AT&T Hobbit is a microprocessor design that AT&T Corporation developed in the early 1990s. It was based on the company's CRISP (C-language Reduced Instruction Set Processor) design, which in turn grew out of Bell Labs' C Machine design of the late 1980s. C Machine, CRISP and Hobbit were optimized for running the C programming language. The design concentrated on fast instruction decoding, indexed array access and procedure calls. Its processor was partially RISC-like. The project ended in 1994 because the Hobbit failed to achieve commercially viable sales.

🔗 Business

A shotgun clause (or Texas Shootout Clause) is a term of art, rather than a legal term. It is a specific type of exit provision that may be included in a shareholders' agreement, and may often be referred to as a buy-sell agreement. The shotgun clause allows a shareholder to offer a specific price per share for the other shareholder(s)' shares; the other shareholder(s) must then either accept the offer or buy the offering shareholder's shares at that price per share.

🔗 Mathematics 🔗 Game theory

Fair cake-cutting is a kind of fair division problem. The problem involves a heterogeneous resource, such as a cake with different toppings, that is assumed to be divisible – it is possible to cut arbitrarily small pieces of it without destroying their value. The resource has to be divided among several partners who have different preferences over different parts of the cake, i.e., some people prefer the chocolate toppings, some prefer the cherries, some just want as large a piece as possible. The division should be unanimously fair – each person should receive a piece believed to be a fair share.

The "cake" is only a metaphor; procedures for fair cake-cutting can be used to divide various kinds of resources, such as land estates, advertisement space or broadcast time.

The prototypical procedure for fair cake-cutting is divide and choose, which is mentioned in the book of Genesis. It solves the fair division problem for two people. The modern study of fair cake-cutting was initiated during World War II, when Hugo Steinhaus asked his students Stefan Banach and Bronisław Knaster to find a generalization of divide-and-choose to three or more people. They developed the last diminisher procedure. Today, fair cake-cutting is the subject of intense research in mathematics, computer science, economics and political science.

🔗 Biography 🔗 Norway

Erik Naggum (June 13, 1965 – June 17, 2009) was a Norwegian computer programmer recognized for his work in the fields of SGML, Emacs and Lisp. Since the early 1990s he was also a provocative participant on various Usenet discussion groups.

Naggum made significant contributions to RFC 1123, which defines and discusses the requirements for Internet host software, and RFC 2049, which defines electronic information transfer of various binary formats through e-mail.

In a 1999 newspaper article in Dagbladet, he was interviewed about his aggressive, confrontational participation in Usenet discussion groups. Erik later stated his motto to be: "Some people are little more than herd animals, flocking together whenever the world becomes uncomfortable … I am not one of those people. If I had a motto, it would probably be Herd thither, me hither."

His death on June 17, 2009 (aged 44), was caused by a massive bleeding ulcer, related to ulcerative colitis, which he was diagnosed with about 15 years before his death.