Have a deep view into what people are curious about.

🔗 Philosophy 🔗 Politics 🔗 Psychology 🔗 Marketing & Advertising 🔗 Philosophy/Philosophy of science 🔗 Philosophy/Epistemology 🔗 Sociology 🔗 Education

Social facilitation is defined as improvement or decrease in individual performance when working with other people rather than alone.

In addition to working together with other people, social facilitation also occurs in the mere presence of other people. Previous research has found that individual performance is improved by coaction, performing a task in the presence of others who are performing a similar task, and having an audience while performing a certain task. An example of coaction triggering social facilitation can be seen in instances where a cyclist's performance is improved when cycling along with other cyclists as compared to cycling alone. An instance where having an audience triggers social facilitation can be observed where a weightlifter lifts heavier weight in the presence of an audience. Social facilitation has occasionally been attributed to the fact that certain people are more susceptible to social influence, with the argument that personality factors can make these people more aware of evaluation.

The Yerkes-Dodson law, when applied to social facilitation, states that "the mere presence of other people will enhance the performance in speed and accuracy of well-practiced tasks, but will degrade in the performance of less familiar tasks." Compared to their performance when alone, when in the presence of others they tend to perform better on simple or well-rehearsed tasks and worse on complex or new ones.

The audience effect attempts to explain psychologically why the presence of an audience leads to people performing tasks better in some cases and worse in others. This idea was further explored when some studies showed that the presence of a passive audience facilitated the better performance of a simple task, while other studies showed that the presence of a passive audience inhibited the performance of a more difficult task or one that was not well practiced, possibly due to psychological pressure or stress. (See Yerkes–Dodson law.)

🔗 Technology 🔗 Sweden 🔗 Metalworking

Gauge blocks (also known as gage blocks, Johansson gauges, slip gauges, or Jo blocks) are a system for producing precision lengths. The individual gauge block is a metal or ceramic block that has been precision ground and lapped to a specific thickness. Gauge blocks come in sets of blocks with a range of standard lengths. In use, the blocks are stacked to make up a desired length.

An important feature of gauge blocks is that they can be joined together with very little dimensional uncertainty. The blocks are joined by a sliding process called wringing, which causes their ultra-flat surfaces to cling together. A small number of gauge blocks can be used to create accurate lengths within a wide range. By using 3 blocks at a time taken from a set of 30 blocks, one may create any of the 1000 lengths from 3.000 to 3.999 mm in 0.001 mm steps (or .3000 to .3999 inches in 0.0001 inch steps). Gauge blocks were invented in 1896 by Swedish machinist Carl Edvard Johansson. They are used as a reference for the calibration of measuring equipment used in machine shops, such as micrometers, sine bars, calipers, and dial indicators (when used in an inspection role). Gauge blocks are the main means of length standardization used by industry.

🔗 Automobiles

A hemispherical combustion chamber is a type of combustion chamber in a reciprocating internal combustion engine with a domed cylinder head. An engine featuring this type of hemispherical chamber is known as a hemi engine.

🔗 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).

🔗 Mathematics

In geometric topology, the Clifford torus is the simplest and most symmetric flat embedding of the cartesian product of two circles S¹_a and S¹_b (in the same sense that the surface of a cylinder is "flat"). It is named after William Kingdon Clifford. It resides in R⁴, as opposed to in R³. To see why R⁴ is necessary, note that if S¹_a and S¹_b each exist in their own independent embedding spaces R²_a and R²_b, the resulting product space will be R⁴ rather than R³. The historically popular view that the cartesian product of two circles is an R³ torus in contrast requires the highly asymmetric application of a rotation operator to the second circle, since that circle will only have one independent axis z available to it after the first circle consumes x and y.

Stated another way, a torus embedded in R³ is an asymmetric reduced-dimension projection of the maximally symmetric Clifford torus embedded in R⁴. The relationship is similar to that of projecting the edges of a cube onto a sheet of paper. Such a projection creates a lower-dimensional image that accurately captures the connectivity of the cube edges, but also requires the arbitrary selection and removal of one of the three fully symmetric and interchangeable axes of the cube.

If S¹_a and S¹_b each has a radius of ${\displaystyle \textstyle {\sqrt {1/2}}}$, their Clifford torus product will fit perfectly within the unit 3-sphere S³, which is a 3-dimensional submanifold of R⁴. When mathematically convenient, the Clifford torus can be viewed as residing inside the complex coordinate space C², since C² is topologically equivalent to R⁴.

The Clifford torus is an example of a square torus, because it is isometric to a square with opposite sides identified. It is further known as a Euclidean 2-torus (the "2" is its topological dimension); figures drawn on it obey Euclidean geometry as if it were flat, whereas the surface of a common "doughnut"-shaped torus is positively curved on the outer rim and negatively curved on the inner. Although having a different geometry than the standard embedding of a torus in three-dimensional Euclidean space, the square torus can also be embedded into three-dimensional space, by the Nash embedding theorem; one possible embedding modifies the standard torus by a fractal set of ripples running in two perpendicular directions along the surface.

🔗 Technology 🔗 Science Fiction 🔗 Transhumanism

Gray goo (also spelled grey goo) is a hypothetical global catastrophic scenario involving molecular nanotechnology in which out-of-control self-replicating machines consume all biomass on Earth while building more of themselves, a scenario that has been called ecophagy ("eating the environment", more literally "eating the habitation"). The original idea assumed machines were designed to have this capability, while popularizations have assumed that machines might somehow gain this capability by accident.

Self-replicating machines of the macroscopic variety were originally described by mathematician John von Neumann, and are sometimes referred to as von Neumann machines or clanking replicators. The term gray goo was coined by nanotechnology pioneer K. Eric Drexler in his 1986 book Engines of Creation. In 2004 he stated, "I wish I had never used the term 'gray goo'." Engines of Creation mentions "gray goo" in two paragraphs and a note, while the popularized idea of gray goo was first publicized in a mass-circulation magazine, Omni, in November 1986.

🔗 United States 🔗 Aviation 🔗 Spaceflight 🔗 Rocketry

The Space Transportation System (STS), also known internally to NASA as the Integrated Program Plan (IPP), was a proposed system of reusable manned space vehicles envisioned in 1969 to support extended operations beyond the Apollo program. (NASA appropriated the name for its Space Shuttle Program, the only component of the proposal to survive Congressional funding approval). The purpose of the system was twofold: to reduce the cost of spaceflight by replacing the current method of launching capsules on expendable rockets with reusable spacecraft; and to support ambitious follow-on programs including permanent orbiting space stations around the Earth and Moon, and a human landing mission to Mars.

In February 1969, President Richard Nixon appointed a Space Task Group headed by Vice President Spiro Agnew to recommend human space projects beyond Apollo. The group responded in September with the outline of the STS, and three different program levels of effort culminating with a human Mars landing by 1983 at the earliest, and by the end of the twentieth century at the latest. The system's major components consisted of:

• A permanent space station module designed for 6 to 12 occupants, in a 270-nautical-mile (500 km) low Earth orbit, and as a permanent lunar orbit station. Modules could be combined in Earth orbit to create a 50 to 100 person permanent station.
• A chemically fueled Earth-to-station shuttle.
• A chemically fueled space tug to move crew and equipment between Earth orbits as high as geosynchronous orbit, which could be adapted as a lunar orbit-to-surface shuttle.
• A nuclear-powered ferry using the NERVA engine, to move crew, spacecraft and supplies between low Earth orbit and lunar orbit, geosynchronous orbit, or to other planets in the solar system.

The tug and ferry vehicles would be of a modular design, allowing them to be clustered and/or staged for large payloads or interplanetary missions. The system would be supported by permanent Earth and lunar orbital propellant depots. The Saturn V might still have been used as a heavy lift launch vehicle for the nuclear ferry and space station modules. A special "Mars Excursion Module" would be the only remaining vehicle necessary for a human Mars landing.

As Apollo accomplished its objective of landing the first men on the Moon, political support for further manned space activities began to wane, which was reflected in unwillingness of the Congress to provide funding for most of these extended activities. Based on this, Nixon rejected all parts of the program except the Space Shuttle, which inherited the STS name. As funded, the Shuttle was greatly scaled back from its planned degree of reusability, and deferred in time. The Shuttle first flew in 1981, and was retired in 2011.

A second part of the system, Space Station Freedom, was approved in the early 1980s and announced in 1984 by president Ronald Reagan. However, this also became politically unviable by 1993, and was replaced with the International Space Station (ISS), with substantial contribution by Russia. The ISS was completed in 2010.

🔗 Novels

I, Libertine is a literary hoax novel that began as a practical joke by late-night radio raconteur Jean Shepherd who aimed to lampoon the process of determining best-selling books. After generating substantial attention for a novel that didn't actually exist, Shepherd approved a 1956 edition of the book written mainly by Theodore Sturgeon — which became an actual best-seller, with all profits donated to charity.

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

A Miyake event is an observed sharp enhancement of the production of cosmogenic isotopes by cosmic rays. It can be marked by a spike in the concentration of radioactive carbon isotope ¹⁴
C in tree rings, as well as ¹⁰
Be and ³⁶
Cl in ice cores, which are all independently dated. At present, five significant events are known (7176 BCE, 5259 BCE, 660 BCE, 774 CE, 993 CE) for which the spike in ¹⁴
C is quite remarkable, i.e. above 1% rise over a period of 2 years, and four more events (12,350 BCE, 5410 BCE, 1052 CE, 1279 CE) need independent confirmation. It is not known how often Miyake events occur, but from the available data it is estimated to be every 400–2400 years.

There is strong evidence that Miyake events are caused by extreme solar particle events and they are likely related to super-flares discovered on solar-like stars. Although Miyake events are based on extreme year-to-year rises of ¹⁴
C concentration, the duration of the periods over which the ¹⁴
C levels increase or stay at high levels is longer than one year. However, a universal cause and origin of all the events is not yet established in science, and some of the events may be caused by other phenomena coming from outer space (such as a gamma-ray burst).

A recently reported sharp spike in ¹⁴
C that occurred between 12,350 and 12,349 BCE, may represent the largest known Miyake event. This event was identified during a study conducted by an international team of researchers who measured radiocarbon levels in ancient trees recovered from the eroded banks of the Drouzet River, near Gap, France, in the Southern French Alps. According to the initial study the new event is roughly twice the size of the Δ¹⁴
C increase for more recent 774 CE and 993 CE events, but the strength of the corresponding solar storm is not yet assessed. However, the newly discovered 12,350 BCE event has not yet been independently confirmed in wood from other regions, nor it is reliably supported by a clear corresponding spike in other isotopes (such as Beryllium-10) that are usually used in combination for absolute radiometric dating.

A Miyake event occurring in modern conditions might have significant impacts on global technological infrastructure such as satellites, telecommunications, and power grids.