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🔗 Computing 🔗 Classical Greece and Rome 🔗 Greece 🔗 Astronomy 🔗 History of Science 🔗 Alternative Views 🔗 Time

The Antikythera mechanism (, ) is an ancient hand powered Greek analogue computer which has also been described as the first example of such device used to predict astronomical positions and eclipses for calendar and astrological purposes decades in advance. It could also be used to track the four-year cycle of athletic games which was similar to an Olympiad, the cycle of the ancient Olympic Games.

This artefact was retrieved from the sea in 1901, and identified on 17 May 1902 as containing a gear by archaeologist Valerios Stais, among wreckage retrieved from a shipwreck off the coast of the Greek island Antikythera. The instrument is believed to have been designed and constructed by Greek scientists and has been variously dated to about 87 BC, or between 150 and 100 BC, or to 205 BC, or to within a generation before the shipwreck, which has been dated to approximately 70–60 BC.

The device, housed in the remains of a 34 cm × 18 cm × 9 cm (13.4 in × 7.1 in × 3.5 in) wooden box, was found as one lump, later separated into three main fragments which are now divided into 82 separate fragments after conservation efforts. Four of these fragments contain gears, while inscriptions are found on many others. The largest gear is approximately 14 centimetres (5.5 in) in diameter and originally had 223 teeth.

It is a complex clockwork mechanism composed of at least 30 meshing bronze gears. A team led by Mike Edmunds and Tony Freeth at Cardiff University used modern computer x-ray tomography and high resolution surface scanning to image inside fragments of the crust-encased mechanism and read the faintest inscriptions that once covered the outer casing of the machine.

Detailed imaging of the mechanism suggests that it had 37 gear wheels enabling it to follow the movements of the Moon and the Sun through the zodiac, to predict eclipses and even to model the irregular orbit of the Moon, where the Moon's velocity is higher in its perigee than in its apogee. This motion was studied in the 2nd century BC by astronomer Hipparchus of Rhodes, and it is speculated that he may have been consulted in the machine's construction.

The knowledge of this technology was lost at some point in antiquity. Similar technological works later appeared in the medieval Byzantine and Islamic worlds, but works with similar complexity did not appear again until the development of mechanical astronomical clocks in Europe in the fourteenth century. All known fragments of the Antikythera mechanism are now kept at the National Archaeological Museum in Athens, along with a number of artistic reconstructions and replicas of the mechanism to demonstrate how it may have looked and worked.

🔗 Astronomy 🔗 Weather 🔗 Astronomy/Solar System 🔗 Weather/Weather 🔗 Weather/Space weather

Saturn's hexagon is a persistent approximately hexagonal cloud pattern around the north pole of the planet Saturn, located at about 78°N. The sides of the hexagon are about 14,500 km (9,000 mi) long, which is about 2,000 km (1,200 mi) longer than the diameter of Earth. The hexagon may be a bit more than 29,000 km (18,000 mi) wide, may be 300 km (190 mi) high, and may be a jet stream made of atmospheric gases moving at 320 km/h (200 mph). It rotates with a period of 10h 39m 24s, the same period as Saturn's radio emissions from its interior. The hexagon does not shift in longitude like other clouds in the visible atmosphere.

Saturn's hexagon was discovered during the Voyager mission in 1981, and was later revisited by Cassini-Huygens in 2006. During the Cassini mission, the hexagon changed from a mostly blue color to more of a golden color. Saturn's south pole does not have a hexagon, as verified by Hubble observations. It does, however, have a vortex, and there is also a vortex inside the northern hexagon. Multiple hypotheses for the hexagonal cloud pattern have been developed.

🔗 Arthropods

Neobuthus factorio is a species of scorpion from the family Buthidae found in Somalia.

🔗 Meteorology 🔗 Chemicals 🔗 Soil 🔗 Weather 🔗 Weather/Weather

Petrichor () is the earthy scent produced when rain falls on dry soil. The word is constructed from Greek petra (πέτρα), meaning "stone", and īchōr (ἰχώρ), the fluid that flows in the veins of the gods in Greek mythology.

🔗 Biography 🔗 Greater Manchester

Frederick Travis Dibnah, (29 April 1938 – 6 November 2004) was an English steeplejack and television personality, with a keen interest in mechanical engineering, who described himself as a "backstreet mechanic".

When Dibnah was born, Britain relied heavily upon coal to fuel its industry. As a child, he was fascinated by the steam engines which powered the many textile mills in Bolton, but he paid particular attention to chimneys and the men who worked on them. He began his working life as a joiner, before becoming a steeplejack. From age 22, he served for two years in the Army Catering Corps of the British Army, undertaking his National Service. Once demobilised, he returned to steeplejacking but met with limited success until he was asked to repair Bolton's parish church. The resulting publicity provided a boost to his business, ensuring he was almost never out of work.

In 1978, while making repairs to Bolton Town Hall, Dibnah was filmed by a regional BBC news crew. The BBC then commissioned a documentary, which followed the rough-hewn steeplejack as he worked on chimneys, interacted with his family and talked about his favourite hobby—steam. His Lanky manner and gentle, self-taught philosophical outlook proved popular with viewers and he featured in a number of television programmes. Toward the end of his life, the decline of Britain's industry was mirrored by a decline in his steeplejacking business and Dibnah increasingly came to rely on public appearances and after-dinner speaking to support his income. In 1998, he presented a programme on Britain's industrial history and went on to present a number of series, largely concerned with the Industrial Revolution and its mechanical and architectural legacy.

He died from bladder cancer in November 2004, aged 66.

🔗 Computer science

In computer architecture, Amdahl's law (or Amdahl's argument) is a formula which gives the theoretical speedup in latency of the execution of a task at fixed workload that can be expected of a system whose resources are improved. It is named after computer scientist Gene Amdahl, and was presented at the AFIPS Spring Joint Computer Conference in 1967.

Amdahl's law is often used in parallel computing to predict the theoretical speedup when using multiple processors. For example, if a program needs 20 hours to complete using a single thread, but a one-hour portion of the program cannot be parallelized, therefore only the remaining 19 hours (p = 0.95) of execution time can be parallelized, then regardless of how many threads are devoted to a parallelized execution of this program, the minimum execution time cannot be less than one hour. Hence, the theoretical speedup is limited to at most 20 times the single thread performance, ${\displaystyle \left({\dfrac {1}{1-p}}=20\right)}$.

🔗 Olympics 🔗 Classical Greece and Rome 🔗 Greece 🔗 Martial arts 🔗 Mixed martial arts

Pankration (; Greek: παγκράτιον) was a sporting event introduced into the Greek Olympic Games in 648 BC and was an empty-hand submission sport with scarcely any rules. The athletes used boxing and wrestling techniques, but also others, such as kicking and holds, locks and chokes on the ground. The term comes from the Greek παγκράτιον [paŋkrátion], literally meaning "all of power" from πᾶν (pan) "all" and κράτος (kratos) "strength, might, power".

It was known in ancient times for its ferocity and allowance of such tactics as knees to the head and eye gouging. One ancient account tells of a situation in which the judges were trying to determine the winner of a match. The difficulty lay in that fact that both men had died in the arena from their injuries, making it hard to determine a victor. Eventually, the judges decided the winner was the one who didn't have his eyes gouged out. Over time, however, maneuvers like eye gouging were discouraged to prevent such unpleasant incidents.

🔗 Biography 🔗 Aviation 🔗 Australia 🔗 Business 🔗 Aviation/aerospace biography 🔗 Scouting

Richard Harold Smith (born 18 March 1944) is an Australian entrepreneur, aviator and philanthropist. He holds a number of aviation world records and is the founder of Dick Smith Electronics, Australian Geographic and Dick Smith Foods. He was selected as 1986 Australian of the Year. In 2010, he founded the media production company Smith&Nasht with the intention of producing films about global issues. In 2015, he was awarded the Companion of the Order of Australia. He is a fellow of the Committee for Skeptical Inquiry.

🔗 Classical Greece and Rome 🔗 Greece 🔗 Food and drink 🔗 Wine 🔗 Invention

A Pythagorean cup (also known as a Pythagoras cup, Greedy Cup, Tantalus cup or i koupa tis dikaiosynis) is a practical joke device in a form of a drinking cup, credited to Pythagoras of Samos. When it is filled beyond a certain point, a siphoning effect causes the cup to drain its entire contents through the base.

🔗 France

Flâneur (French: [flɑnœʁ]) is a French term popularized in the nineteenth-century for a type of urban male "stroller", "lounger", "saunterer", or "loafer". The word has some nuanced additional meanings (including as a loanword into English). Traditionally depicted as male, a flâneur is an ambivalent figure of urban affluence and modernity, representing the ability to wander detached from society with no other purpose than to be an acute observer of industrialized, contemporary life. Flânerie is the act of strolling, with all of its accompanying associations. A near-synonym of the noun is boulevardier.

The flâneur was first a literary type from 19th-century France, essential to any picture of the streets of Paris. The word carried a set of rich associations: the man of leisure, the idler, the urban explorer, the connoisseur of the street. However, the flâneur's origins are to be found in journalism of the Restoration, and the politics of post-revolutionary public space. Drawing on the work of Charles Baudelaire who described the flâneur in his poetry and 1863 essay "The Painter of Modern Life", Walter Benjamin promoted 20th-century scholarly interest in the flâneur as an emblematic archetype of urban, modern (even modernist) experience. Following Benjamin, the flâneur has become an important symbol for scholars, artists, and writers. The classic French female counterpart is the passante, dating to the works of Marcel Proust, though a 21st-century academic coinage is flâneuse, and some English-language writers simply apply the masculine flâneur also to women. The term has acquired an additional architecture and urban planning sense, referring to passers-by who experience incidental or intentional psychological effects from the design of a structure.