Have a deep view into what people are curious about.

🔗 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.

🔗 Sociology

The Matthew effect of accumulated advantage, Matthew principle, or Matthew effect for short, is sometimes summarized by the adage "the rich get richer and the poor get poorer". The concept is applicable to matters of fame or status, but may also be applied literally to cumulative advantage of economic capital. In the beginning, Matthew effects were primarily focused on the inequality in the way scientists were recognized for their work. However, Norman Storer, of Columbia University, led a new wave of research. He believed he discovered that the inequality that existed in the social sciences also existed in other institutions.

The term was coined by sociologist Robert K. Merton in 1968 and takes its name from the Parable of the talents or minas in the biblical Gospel of Matthew. Merton credited his collaborator and wife, sociologist Harriet Zuckerman, as co-author of the concept of the Matthew effect.

🔗 Soviet Union 🔗 Military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/World War II 🔗 Military history/Russian, Soviet and CIS military history

Deep operation (Russian: Глубокая операция, glubokaya operatsiya), also known as Soviet Deep Battle, was a military theory developed by the Soviet Union for its armed forces during the 1920s and 1930s. It was a tenet that emphasized destroying, suppressing or disorganizing enemy forces not only at the line of contact, but throughout the depth of the battlefield.

The term comes from Vladimir Triandafillov, an influential military writer, who worked with others to create a military strategy with its own specialized operational art and tactics. The concept of deep operations was a national strategy, tailored to the economic, cultural and geopolitical position of the Soviet Union. In the aftermath of several failures or defeats in the Russo-Japanese War, First World War and Polish–Soviet War, the Soviet High Command (Stavka) focused on developing new methods for the conduct of war. This new approach considered military strategy and tactics, but also introduced a new intermediate level of military art: operations. The Soviet Union was the first country to officially distinguish the third level of military thinking which occupied the position between strategy and tactics.

Using these templates, the Soviets developed the concept of deep battle and by 1936 it had become part of the Red Army Field Regulations. Deep operations had two phases: the tactical deep battle, followed by the exploitation of tactical success, known as the conduct of deep battle operations. Deep battle envisaged the breaking of the enemy's forward defenses, or tactical zones, through combined arms assaults, which would be followed up by fresh uncommitted mobile operational reserves sent to exploit the strategic depth of an enemy front. The goal of a deep operation was to inflict a decisive strategic defeat on the enemy's logistical abilities and render the defence of their front more difficult, impossible—or, indeed, irrelevant. Unlike most other doctrines, deep battle stressed combined arms cooperation at all levels: strategic, operational, and tactical.

🔗 Video games 🔗 Visual arts

The Atari Video Music (Model C240) is the earliest commercial electronic music visualizer released. It was manufactured by Atari, Inc., and released in 1977 for $169.95. The system creates an animated visual display that responds to musical input from a Hi-Fi stereo system for the visual entertainment of consumers.

🔗 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.

🔗 Food and drink 🔗 Insects 🔗 Forestry

Shellac () is a resin secreted by the female lac bug on trees in the forests of India and Thailand. Chemically, it is mainly composed of aleuritic acid, jalaric acid, shellolic acid, and other natural waxes. It is processed and sold as dry flakes and dissolved in alcohol to make liquid shellac, which is used as a brush-on colorant, food glaze and wood finish. Shellac functions as a tough natural primer, sanding sealant, tannin-blocker, odour-blocker, stain, and high-gloss varnish. Shellac was once used in electrical applications as it possesses good insulation qualities and seals out moisture. Phonograph and 78 rpm gramophone records were made of shellac until they were replaced by vinyl long-playing records from 1948 onwards.

From the time shellac replaced oil and wax finishes in the 19th century, it was one of the dominant wood finishes in the western world until it was largely replaced by nitrocellulose lacquer in the 1920s and 1930s.

🔗 Mathematics

The gömböc (Hungarian: [ˈɡømbøt͡s]) is a convex three-dimensional homogeneous body that when resting on a flat surface has just one stable and one unstable point of equilibrium. Its existence was conjectured by the Russian mathematician Vladimir Arnold in 1995 and proven in 2006 by the Hungarian scientists Gábor Domokos and Péter Várkonyi. The gömböc shape is not unique; it has countless varieties, most of which are very close to a sphere and all with a very strict shape tolerance (about 0.1 mm per 100 mm).

The most famous solution, capitalized as Gömböc to distinguish it from the generic gömböc, has a sharpened top, as shown in the photo. Its shape helped to explain the body structure of some tortoises in relation to their ability to return to equilibrium position after being placed upside down. Copies of the gömböc have been donated to institutions and museums, and the largest one was presented at the World Expo 2010 in Shanghai in China. In December 2017, a 4.5 m gömböc statue was installed in the Corvin Quarter in Budapest.

🔗 Energy 🔗 Stanford University/SRI International 🔗 Stanford University

The cubic mile of oil (CMO) is a unit of energy, aiming to give the general public an understanding of large quantities of energy. It is approximately equal to 1.6×10²⁰ joule. It was created by Hew Crane of SRI International to aid in public understanding of global-scale energy consumption and resources.

Large scale sources of energy include wind, solar photovoltaic, solar thermal, nuclear, hydroelectric, oil, coal, natural gas, geothermal, and biomass (primarily the burning of wood). Traditionally, many different units are commonly used to measure these sources (e.g., joules, BTUs, kilowatt hours, therms) but only some of them are familiar to a global general public, and some argue that fewer are needed and a standard should be chosen. Still, these common energy units are mainly sized for everyday activities, for example a joule is the energy required to lift a small apple one metre vertically. For regional, national, and global scales, larger energy units, such as exajoule, terawatt-hour, billion barrels of oil equivalent (BBOE) and quad are used. Derived by multiplying the small common units by large powers of ten these larger units pose additional conceptual difficulties for many citizens.

Crane intended the cubic mile of oil to provide a visualizable scale for comparing the contributions of these diverse energy components as a percentage of total worldwide, energy use.

In 2005, the global economy was consuming approximately 30 billion barrels (4.8 billion cubic metres; 1.3 trillion US gallons) of oil each year. Numbers of this magnitude are difficult to conceive by most people. The volume occupied by 1 trillion US gallons (3.8 billion cubic metres) is about 1 cubic mile (4.2 billion cubic metres). Crane felt that a cubic mile would be an easier concept for the general public than a trillion gallons.

🔗 Technology 🔗 Energy

In pipeline transportation, pigging is the practice of using devices known as pigs or scrapers to perform various maintenance operations. This is done without stopping the flow of the product in the pipeline. These devices are known as pigs because they scrape or clean just like a normal pig.

These operations include but are not limited to cleaning and inspecting the pipeline. This is accomplished by inserting the pig into a "pig launcher" (or "launching station") — an oversized section in the pipeline, reducing to the normal diameter. The launching station is then closed and the pressure-driven flow of the product in the pipeline is used to push the pig along down the pipe until it reaches the receiving trap — the "pig catcher" (or "receiving station").

🔗 Technology 🔗 China/Chinese history 🔗 China 🔗 Lists 🔗 Invention

China has been the source of many innovations, scientific discoveries and inventions. This includes the Four Great Inventions: papermaking, the compass, gunpowder, and printing (both woodblock and movable type). The list below contains these and other inventions in China attested by archaeological or historical evidence.

The historical region now known as China experienced a history involving mechanics, hydraulics and mathematics applied to horology, metallurgy, astronomy, agriculture, engineering, music theory, craftsmanship, naval architecture and warfare. By the Warring States period (403–221 BC), inhabitants of the Warring States had advanced metallurgic technology, including the blast furnace and cupola furnace, while the finery forge and puddling process were known by the Han Dynasty (202 BC–AD 220). A sophisticated economic system in imperial China gave birth to inventions such as paper money during the Song Dynasty (960–1279). The invention of gunpowder during the mid 9th century led to an array of inventions such as the fire lance, land mine, naval mine, hand cannon, exploding cannonballs, multistage rocket and rocket bombs with aerodynamic wings and explosive payloads. With the navigational aid of the 11th century compass and ability to steer at high sea with the 1st century sternpost rudder, premodern Chinese sailors sailed as far as East Africa. In water-powered clockworks, the premodern Chinese had used the escapement mechanism since the 8th century and the endless power-transmitting chain drive in the 11th century. They also made large mechanical puppet theaters driven by waterwheels and carriage wheels and wine-serving automatons driven by paddle wheel boats.

The contemporaneous Peiligang and Pengtoushan cultures represent the oldest Neolithic cultures of China and were formed around 7000 BC. Some of the first inventions of Neolithic China include semilunar and rectangular stone knives, stone hoes and spades, the cultivation of millet and the soybean, the refinement of sericulture, rice cultivation, the creation of pottery with cord-mat-basket designs, the creation of pottery vessels and pottery steamers and the development of ceremonial vessels and scapulimancy for purposes of divination. The British sinologist Francesca Bray argues that the domestication of the ox and buffalo during the Longshan culture (c. 3000–c. 2000 BC) period, the absence of Longshan-era irrigation or high-yield crops, full evidence of Longshan cultivation of dry-land cereal crops which gave high yields "only when the soil was carefully cultivated," suggest that the plough was known at least by the Longshan culture period and explains the high agricultural production yields which allowed the rise of Chinese civilization during the Shang Dynasty (c. 1600–c. 1050 BC). Later inventions such as the multiple-tube seed drill and heavy moldboard iron plough enabled China to sustain a much larger population through greater improvements in agricultural output.

For the purposes of this list, inventions are regarded as technological firsts developed in China, and as such does not include foreign technologies which the Chinese acquired through contact, such as the windmill from the Middle East or the telescope from early modern Europe. It also does not include technologies developed elsewhere and later invented separately by the Chinese, such as the odometer, water wheel, and chain pump. Scientific, mathematical or natural discoveries, changes in minor concepts of design or style and artistic innovations do not appear on the list.