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🔗 Mathematics

Pentagramma mirificum (Latin for miraculous pentagram) is a star polygon on a sphere, composed of five great circle arcs, all of whose internal angles are right angles. This shape was described by John Napier in his 1614 book Mirifici logarithmorum canonis descriptio (Description of the wonderful rule of logarithms) along with rules that link the values of trigonometric functions of five parts of a right spherical triangle (two angles and three sides). The properties of pentagramma mirificum were studied, among others, by Carl Friedrich Gauss.

🔗 Aviation 🔗 Russia 🔗 Military history 🔗 Disaster management 🔗 Aviation/Aviation accident 🔗 Death 🔗 Ukraine 🔗 Netherlands 🔗 Military history/Russian, Soviet and CIS military history 🔗 Malaysia

Malaysia Airlines Flight 17 (MH17/MAS17) was a scheduled passenger flight from Amsterdam to Kuala Lumpur that was shot down on 17 July 2014 while flying over eastern Ukraine. All 283 passengers and 15 crew were killed. Contact with the aircraft, a Boeing 777-200ER, was lost when it was about 50 km (31 mi) from the Ukraine–Russia border, and wreckage of the aircraft fell near Hrabove in Donetsk Oblast, Ukraine, 40 km (25 mi) from the border. The shoot-down occurred in the War in Donbas in an area controlled by pro-Russian rebels.

The responsibility for investigation was delegated to the Dutch Safety Board (DSB) and the Dutch-led joint investigation team (JIT), who concluded that the airliner was downed by a Buk surface-to-air missile launched from pro-Russian separatist-controlled territory in Ukraine. According to the JIT, the Buk that was used originated from the 53rd Anti-Aircraft Missile Brigade of the Russian Federation and had been transported from Russia on the day of the crash, fired from a field in a rebel-controlled area and the launch system returned to Russia afterwards. The findings by the DSB and JIT are consistent with the earlier claims by American and German intelligence sources and claims by the Ukrainian government. On the basis of the JIT's conclusions, the governments of the Netherlands and Australia held Russia responsible for the deployment of the Buk installation and were pursuing legal routes as of May 2018. The Russian government denied involvement in the shooting down of the airplane, and its account of how the aircraft was shot down has varied over time. Coverage in Russian media has also differed from that in other countries.

This was Malaysia Airlines' second aircraft loss during 2014, after the disappearance of Flight 370 on 8 March, and is the deadliest airliner shoot-down incident to date.

🔗 Skepticism 🔗 Indonesia 🔗 Archaeology

Gunung Padang is a megalithic site located in Karyamukti, Campaka, Cianjur Regency, West Java, Indonesia, 30 kilometres (19 mi) southwest of the regency seat or 8 kilometres (5.0 mi) from Lampegan station. Located at 885 metres (2,904 ft) above sea level, the site covers a hill, an extinct volcano, in a series of five terraces bordered by retaining walls of stone that are accessed by 370 successive andesite steps rising about 95 metres (312 ft). It is covered with massive hexagonal stone columns of volcanic origin. The Sundanese people consider the site sacred and believe it was the result of King Siliwangi's attempt to build a palace in one night.

Gunung Padang consists of a series of five artificial terraces, one rectangular and four trapezoidal, that occur, one through five, at successively higher elevations. These terraces also become sucessively smaller with elevation with the first terrace as the lowest and largest and the fifth terrace as the highest and smallest. These terraces lie along the a central, longitudinal NW-SE axis. They are artificial platforms created by lowering high spots and filling in low spots with fill until a flat surface was achieved. The terrace perimeters consist of perimeter retaining walls formed by volcanic polygonal columns stacked horizontally and posted vertically as posts. This terrace complex is accessed by a central stairway with 370 steps, an inclination of 45 degrees, and a length of 110 m (360 ft).

🔗 Ships

A sea anchor (also known as a parachute anchor, drift anchor, drift sock, para-anchor or boat brake) is a device that is streamed from a boat in heavy weather. Its purpose is to stabilize the vessel and to limit progress through the water. Rather than tethering the boat to the seabed with a conventional anchor, a sea anchor provides hydrodynamic drag, thereby acting as a brake. Normally attached to a vessel's bows, a sea anchor can prevent the vessel from turning broadside to the waves and being overwhelmed by them.

Early sea anchors were crude devices, but today most take the form of a marine drogue parachute. These are so efficient that they need a tripping line to collapse the parachute for retrieval. Being made of fabric, a sea parachute may be bagged and easily stowed when not in use.

A similar device to the sea anchor is the much smaller drogue, which is streamed from a vessel's stern in strong winds so as to slow the boat to prevent pitchpoling or broaching in an overtaking sea. The fundamental difference between the sea anchor and the drogue is that the drogue will slow the boat while keeping the heading steady, and is intended to be launched from the stern. The parachute anchor is designed to be launched from the bow and effectively stop the boat's progress relative to the current in an open sea.

🔗 Fashion

Trousers or pants (American English) are an item of clothing that might have originated in Central Asia, worn from the waist to the ankles, covering both legs separately (rather than with cloth extending across both legs as in robes, skirts, and dresses).

Outside North America, the word pants generally means underwear and not trousers. Shorts are similar to trousers, but with legs that come down only to around the area of the knee, higher or lower depending on the style of the garment. To distinguish them from shorts, trousers may be called "long trousers" in certain contexts such as school uniform, where tailored shorts may be called "short trousers", especially in the UK.

The oldest known trousers were found at the Yanghai cemetery in Turpan, Xinjiang, western China and dated to the period between the 10th and the 13th centuries BC. Made of wool, the trousers had straight legs and wide crotches and were likely made for horseback riding.

In most of Europe, trousers have been worn since ancient times and throughout the Medieval period, becoming the most common form of lower-body clothing for adult males in the modern world. Breeches were worn instead of trousers in early modern Europe by some men in higher classes of society. Distinctive formal trousers are traditionally worn with formal and semi-formal day attire. Since the mid-20th century, trousers have increasingly been worn by women as well.

Jeans, made of denim, are a form of trousers for casual wear widely worn all over the world by both sexes. Shorts are often preferred in hot weather or for some sports and also often by children and adolescents. Trousers are worn on the hips or waist and are often held up by buttons, elastic, a belt or suspenders (braces).

🔗 Film 🔗 Military history 🔗 Military history/World War II 🔗 Japan 🔗 Military history/Asian military history 🔗 Military history/Japanese military history 🔗 Film/War films 🔗 Military history/War films 🔗 Anime and manga 🔗 Japan/Japanese cinema 🔗 Anime and manga/Studio Ghibli 🔗 Film/Japanese cinema 🔗 Film/Animated films

Grave of the Fireflies (Japanese: 火垂るの墓, Hepburn: Hotaru no Haka) is a 1988 Japanese animated war drama film written and directed by Isao Takahata, and produced by Studio Ghibli. It is based on the 1967 semi-autobiographical short story Grave of the Fireflies by Akiyuki Nosaka.

The film stars Tsutomu Tatsumi, Ayano Shiraishi, Yoshiko Shinohara and Akemi Yamaguchi. Set in the city of Kobe, Japan, it tells the story of siblings and war orphans Seita and Setsuko, and their desperate struggle to survive during the final months of World War II. Universally acclaimed, Grave of the Fireflies has been ranked as one of the greatest war films of all time and is recognized as a major work of Japanese animation.

🔗 Computing 🔗 Computing/Early computers

Lehmer sieves are mechanical devices that implement sieves in number theory. Lehmer sieves are named for Derrick Norman Lehmer and his son Derrick Henry Lehmer. The father was a professor of mathematics at the University of California, Berkeley at the time, and his son followed in his footsteps as a number theorist and professor at Berkeley.

A sieve in general is intended to find the numbers which are remainders when a set of numbers are divided by a second set. Generally, they are used in finding solutions of Diophantine equations or to factor numbers. A Lehmer sieve will signal that such solutions are found in a variety of ways depending on the particular construction.

🔗 Physics 🔗 China 🔗 Astronomy 🔗 History of Science 🔗 Astronomy/Astronomical objects 🔗 Arab world

SN 1006 was a supernova that is likely the brightest observed stellar event in recorded history, reaching an estimated −7.5 visual magnitude, and exceeding roughly sixteen times the brightness of Venus. Appearing between April 30 and May 1, 1006 AD in the constellation of Lupus, this "guest star" was described by observers across the modern day countries of China, Japan, Iraq, Egypt, and the continent of Europe, and possibly recorded in North American petroglyphs. Some reports state it was clearly visible in the daytime. Modern astronomers now consider its distance from Earth to be about 7,200 light-years.

🔗 United States 🔗 Human rights 🔗 History 🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Philosophy 🔗 Business 🔗 Politics 🔗 Philosophy/Social and political philosophy 🔗 Alternative Views 🔗 Sociology 🔗 Discrimination 🔗 Politics/American politics 🔗 United States/U.S. history

The Business Plot was a political conspiracy in 1933 in the United States. Retired Marine Corps Major General Smedley Butler revealed that wealthy businessmen were plotting to create a fascist veterans' organization with Butler as its leader and use it in a coup d'état to overthrow President Franklin D. Roosevelt. In 1934, Butler testified before the United States House of Representatives Special Committee on Un-American Activities (the "McCormack–Dickstein Committee") on these revelations. No one was prosecuted.

At the time of the incidents, news media dismissed the plot, with a New York Times editorial characterizing it as a "gigantic hoax". While historians have not accepted the notion of a plot, they agree that Butler described one.

🔗 India 🔗 Board and table games

Ganjifa, Ganjapa or Gânjaphâ, is a card game and type of playing cards that are most associated with Persia and India. After Ganjifa cards fell out of use in Iran before the twentieth century, India became the last country to produce them. The form prevalent in Odisha is Ganjapa.