Have a deep view into what people are curious about.

🔗 Spaceflight

The Nuclear Engine for Rocket Vehicle Application (NERVA) was a nuclear thermal rocket engine development program that ran for roughly two decades. Its principal objective was to "establish a technology base for nuclear rocket engine systems to be utilized in the design and development of propulsion systems for space mission application". It was a joint effort of the Atomic Energy Commission (AEC) and the National Aeronautics and Space Administration (NASA), and was managed by the Space Nuclear Propulsion Office (SNPO) until the program ended in January 1973. SNPO was led by NASA's Harold Finger and AEC's Milton Klein.

NERVA had its origins in Project Rover, an AEC research project at the Los Alamos Scientific Laboratory (LASL) with the initial aim of providing a nuclear-powered upper stage for the United States Air Force intercontinental ballistic missiles. Nuclear thermal rocket engines promised to be more efficient than chemical ones. After the formation of NASA in 1958, Project Rover was continued as a civilian project and was reoriented to producing a nuclear powered upper stage for NASA's Saturn V Moon rocket. Reactors were tested at very low power before being shipped to Jackass Flats in the Nevada Test Site. While LASL concentrated on reactor development, NASA built and tested complete rocket engines.

The AEC, SNPO, and NASA considered NERVA a highly successful program in that it met or exceeded its program goals. It demonstrated that nuclear thermal rocket engines were a feasible and reliable tool for space exploration, and at the end of 1968 SNPO deemed that the latest NERVA engine, the XE, met the requirements for a human mission to Mars. It had strong political support from Senators Clinton P. Anderson and Margaret Chase Smith but was cancelled by President Richard Nixon in 1973. Although NERVA engines were built and tested as much as possible with flight-certified components and the engine was deemed ready for integration into a spacecraft, they never flew in space.

🔗 Cetaceans

The 52-hertz whale is an individual whale of unidentified species which calls at the very unusual frequency of 52 Hz. This pitch is a much higher frequency than that of the other whale species with migration patterns most closely resembling this whale's – the blue whale (10–39 Hz) or fin whale (20 Hz). It has been detected regularly in many locations since the late 1980s and appears to be the only individual emitting a whale call at this frequency. It has been described as the "world's loneliest whale".

🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Military history/Military science, technology, and theory 🔗 Physics 🔗 Military history/World War II 🔗 Physics/History

The Einstein–Szilárd letter was a letter written by Leó Szilárd and signed by Albert Einstein that was sent to the United States President Franklin D. Roosevelt on August 2, 1939. Written by Szilárd in consultation with fellow Hungarian physicists Edward Teller and Eugene Wigner, the letter warned that Germany might develop atomic bombs and suggested that the United States should start its own nuclear program. It prompted action by Roosevelt, which eventually resulted in the Manhattan Project developing the first atomic bombs.

🔗 Economics 🔗 Business 🔗 Marketing & Advertising 🔗 Guild of Copy Editors

In marketing strategy, first-mover advantage (FMA) is the advantage gained by the initial ("first-moving") significant occupant of a market segment. First-mover advantage may be gained by technological leadership, or early purchase of resources.

A market participant has first-mover advantage if it is the first entrant and gains a competitive advantage through control of resources. With this advantage, first-movers can be rewarded with huge profit margins and a monopoly-like status.

Not all first-movers are rewarded. If the first-mover does not capitalize on its advantage, its "first-mover disadvantages" leave opportunity for new entrants to enter the market and compete more effectively and efficiently than the first-movers; such firms have "second-mover advantage".

🔗 Germany 🔗 Disaster management 🔗 European history 🔗 Royalty and Nobility 🔗 Germany/Holy Roman Empire

In July 1184, Henry VI, King of Germany (later Holy Roman Emperor), held court at a Hoftag in the Petersberg Citadel in Erfurt. On the morning of 26 July, the combined weight of the assembled nobles caused the wooden second story floor of the building to collapse and most of them fell through into the latrine cesspit below the ground floor, where about 60 of them drowned in liquid excrement. This event is called Erfurter Latrinensturz (lit. 'Erfurt latrine fall') in several German sources.

🔗 Climate change 🔗 Europe 🔗 Energy

The European super grid is a possible future super grid that would ultimately interconnect the various European countries and the regions around Europe's borders – including North Africa, Kazakhstan, and Turkey – with a high-voltage direct current (HVDC) power grid.

It is envisaged that a European super grid would:

• lower the cost of power in all participating countries by allowing the entire region to share the most efficient power plants;
• pool load variability and power station unreliability, reducing the margin of inefficient spinning reserve and standby that have to be supplied;
• allow for wider use of renewable energy, particularly wind energy, from the concept that "it is always windy somewhere" – in particular it tends to be windy in the summer in North Africa, and windy in the winter in Europe;
• allow wide sharing of the total European hydro power resource, which is about 6 weeks of full load European output;
• decrease Europe's dependence on imported fuels.

🔗 Literature

In literature, the competent man is a stock character who exhibits a very wide range of abilities and knowledge, making him a form of polymath. While not the first to use such a character type, the heroes and heroines of Robert A. Heinlein's fiction (with Jubal Harshaw being a prime example) generally have a wide range of abilities, and one of Heinlein's characters, Lazarus Long, gives a wide summary of requirements:

A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyse a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.

The competent man, more often than not, is written without explaining how he achieved his wide range of skills and abilities. When such characters are young, there is often not much explanation as to how they acquired so many skills at an early age.

🔗 Biography 🔗 Korea 🔗 Biography/science and academia

Kim Ung-Yong (Hangul: 김웅용; born March 8, 1962) is a South Korean professor and former child prodigy, who once held the Guinness World Record for highest IQ, at a score of 230+.

The MU puzzle is a puzzle stated by Douglas Hofstadter and found in Gödel, Escher, Bach involving a simple formal system called "MIU". Hofstadter's motivation is to contrast reasoning within a formal system (ie., deriving theorems) against reasoning about the formal system itself. MIU is an example of a Post canonical system and can be reformulated as a string rewriting system.

🔗 Germany 🔗 Astronomy 🔗 Archaeology 🔗 Visual arts

The Nebra sky disk is a bronze disk of around 30 centimeters (11 ³⁄₄ in) diameter and a weight of 2.2 kilograms (4.9 lb), having a blue-green patina and inlaid with gold symbols. These symbols are interpreted generally as the Sun or full moon, a lunar crescent, and stars (including a cluster of seven interpreted as the Pleiades). Two golden arcs along the sides, interpreted to mark the angle between the solstices, were added later. A final addition was another arc at the bottom surrounded with multiple strokes (of uncertain meaning, variously interpreted as a Solar Barge with numerous oars, the Milky Way, or a rainbow).

The disk is attributed to a site in present-day Germany near Nebra, Saxony-Anhalt, and dated by Archaeological association to c. 1600 BC. Researchers suggest the disk is an artifact of the Bronze Age Unetice culture.

The style in which the disk is executed was unlike any artistic style then known from the period, with the result that the object was initially suspected of being a forgery, but is now widely accepted as authentic.

The Nebra sky disk features the oldest concrete depiction of the cosmos yet known from anywhere in the world. In June 2013 it was included in the UNESCO Memory of the World Register and termed "one of the most important archaeological finds of the twentieth century."