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Incandescent light bulb

An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a filament that is heated until it glows. The filament is enclosed in a glass bulb that is either evacuated or filled with inert gas to protect the filament from oxidation. Electric current is supplied to the filament by terminals or wires embedded in the glass. A bulb socket provides mechanical support and electrical connections.

Incandescent bulbs are manufactured in a wide range of sizes, light output, and voltage ratings, from 1.5 volts to about 300 volts. They require no external regulating equipment, have low manufacturing costs, and work equally well on either alternating current or direct current. As a result, the incandescent bulb became widely used in household and commercial lighting, for portable lighting such as table lamps, car headlamps, and flashlights, and for decorative and advertising lighting.

Incandescent bulbs are much less efficient than other types of electric lighting. Less than 5% of the energy they consume is converted into visible light; the rest is lost as heat. The luminous efficacy of a typical incandescent bulb for 120 V operation is 16 lumens per watt (lm/W), compared with 60 lm/W for a compact fluorescent bulb or 100 lm/W for typical white LED lamps.

The heat produced by filaments is used in some applications, such as heat lamps in incubators, lava lamps, Edison effect bulbs, and the Easy-Bake Oven toy. Quartz envelope halogen infrared heaters are used for industrial processes such as paint curing and space heating.

Incandescent bulbs typically have short lifetimes compared with other types of lighting; around 1,000 hours for home light bulbs versus typically 10,000 hours for compact fluorescents and 20,000–30,000 hours for lighting LEDs. Most incandescent bulbs can be replaced by fluorescent lamps, high-intensity discharge lamps, and light-emitting diode lamps (LED). Some governments have begun a phase-out of incandescent light bulbs to reduce energy consumption.

History
Historians Robert Friedel and Paul Israel list inventors of incandescent lamps prior to Joseph Swan and Thomas Edison of General Electric. They conclude that Edison's version was the first practical implementation, able to outstrip the others because of a combination of four factors: an effective incandescent material; a vacuum higher than other implementations which was achieved through the use of a Sprengel pump; a high resistance that made power distribution from a centralized source economically viable, and the development of the associated components required for a large-scale lighting system.

Historian Thomas Hughes has attributed Edison's success to his development of an entire, integrated system of electric lighting. "The lamp was a small component in his system of electric lighting, and no more critical to its effective functioning than the Edison Jumbo generator, the Edison main and feeder, and the parallel-distribution system. Other inventors with generators and incandescent lamps, and with comparable ingenuity and excellence, have long been forgotten because their creators did not preside over their introduction in a system of lighting."

Early pre-commercial research
In 1761, Ebenezer Kinnersley demonstrated heating a wire to incandescence. However such wires tended to melt or oxidize very rapidly (burn) in the presence of air. Limelight became a popular form of stage lighting in the early 19th century, by heating a piece of calcium oxide to incandescence with an oxyhydrogen torch.

In 1802, Humphry Davy used what he described as "a battery of immense size", consisting of 2,000 cells housed in the basement of the Royal Institution of Great Britain, to create an incandescent light by passing the current through a thin strip of platinum, chosen because the metal had an extremely high melting point. It was not bright enough nor did it last long enough to be practical, but it was the precedent behind the efforts of scores of experimenters over the next 75 years. Davy also demonstrated the electric arc, by passing high current between two pieces of charcoal.

For the next 40 years much research was given to turning the carbon arc lamp into a practical means of lighting. The carbon arc itself was dim and violet in color, emitting most of its energy in the ultraviolet, but the positive electrode was heated to just below the melting point of carbon and glowed very brightly with incandescence very close to that of sunlight. Arc lamps burned up their carbon rods very rapidly, expelled dangerous carbon monoxide, and tended to produce outputs in the tens of kilowatts. Therefore, they were only practical for lighting large areas, so researchers continued to search for a way to make lamps suitable for home use.

Over the first three-quarters of the 19th century, many experimenters worked with various combinations of platinum or iridium wires, carbon rods, and evacuated or semi-evacuated enclosures. Many of these devices were demonstrated and some were patented.

In 1835, James Bowman Lindsay demonstrated a constant electric light at a public meeting in Dundee, Scotland. He stated that he could "read a book at a distance of one and a half feet". However he did not develop the electric light any further.

In 1838, Belgian lithographer Marcellin Jobard invented an incandescent light bulb with a vacuum atmosphere using a carbon filament.

In 1840, British scientist Warren De la Rue enclosed a coiled platinum filament in a vacuum tube and passed an electric current through it. The design was based on the concept that the high melting point of platinum would allow it to operate at high temperatures and that the evacuated chamber would contain fewer gas molecules to react with the platinum, improving its longevity. Although a workable design, the cost of the platinum made it impractical for commercial use.

In 1841, Frederick de Moleyns of England was granted the first patent for an incandescent lamp, with a design using platinum wires contained within a vacuum bulb. He also used carbon.

In 1845, American John W. Starr patented an incandescent light bulb using carbon filaments. His invention was never produced commercially.

In 1851, Jean Eugène Robert-Houdin publicly demonstrated incandescent light bulbs on his estate in Blois, France. His light bulbs are on display in the museum of the Château de Blois.

In 1859, Moses G. Farmer built an electric incandescent light bulb using a platinum filament. Thomas Edison later saw one of these bulbs in a shop in Boston, and asked Farmer for advice on the electric light business.

In 1872, Russian Alexander Lodygin invented an incandescent light bulb and obtained a Russian patent in 1874. He used as a burner two carbon rods of diminished section in a glass receiver, hermetically sealed, and filled with nitrogen, electrically arranged so that the current could be passed to the second carbon when the first had been consumed. Later he lived in the US, changed his name to Alexander de Lodyguine and applied for and obtained patents for incandescent lamps having chromium, iridium, rhodium, ruthenium, osmium, molybdenum and tungsten filaments, and a bulb using a molybdenum filament was demonstrated at the world fair of 1900 in Paris.

On 24 July 1874, a Canadian patent was filed by Henry Woodward and Mathew Evans for a lamp consisting of carbon rods mounted in a nitrogen-filled glass cylinder. They were unsuccessful at commercializing their lamp, and sold rights to their patent to Thomas Edison in 1879. (Edison needed ownership of the novel claim of lamps connected in a parallel circuit).

On 4 March 1880, just five months after Edison's light bulb, Alessandro Cruto created his first incandescent lamp. Cruto produced a filament by deposition of graphite on thin platinum filaments, by heating it with an electric current in the presence of gaseous ethyl alcohol. Heating this platinum at high temperatures leaves behind thin filaments of platinum coated with pure graphite. By September 1881 he had achieved a successful version of this the first synthetic filament. The light bulb invented by Cruto lasted five hundred hours as opposed to the forty of Edison's original version. In 1882 Munich Electrical Exhibition in Bavaria, Germany Cruto's lamp was more efficient than the Edison's one and produced a better, white light.

In 1893, Heinrich Göbel claimed he had designed the first incandescent light bulb in 1854, with a thin carbonized bamboo filament of high resistance, platinum lead-in wires in an all-glass envelope, and a high vacuum. Judges of four courts raised doubts about the alleged Göbel anticipation, but there was never a decision in a final hearing due to the expiration of Edison's patent. A research work published in 2007 concluded that the story of the Göbel lamps in the 1850s is fictitious.

Carbon filament and vacuum
Joseph Swan (1828–1914) was a British physicist and chemist. In 1850, he began working with carbonized paper filaments in an evacuated glass bulb. By 1860, he was able to demonstrate a working device but the lack of a good vacuum and an adequate supply of electricity resulted in a short lifetime for the bulb and an inefficient source of light. By the mid-1870s better pumps had become available, and Swan returned to his experiments.

With the help of Charles Stearn, an expert on vacuum pumps, in 1878, Swan developed a method of processing that avoided the early bulb blackening. This received a British Patent in 1880. On 18 December 1878, a lamp using a slender carbon rod was shown at a meeting of the Newcastle Chemical Society, and Swan gave a working demonstration at their meeting on 17 January 1879. It was also shown to 700 who attended a meeting of the Literary and Philosophical Society of Newcastle upon Tyne on 3 February 1879. These lamps used a carbon rod from an arc lamp rather than a slender filament. Thus they had low resistance and required very large conductors to supply the necessary current, so they were not commercially practical, although they did furnish a demonstration of the possibilities of incandescent lighting with relatively high vacuum, a carbon conductor, and platinum lead-in wires. This bulb lasted about 40 hours.

Swan then turned his attention to producing a better carbon filament and the means of attaching its ends. He devised a method of treating cotton to produce 'parchmentised thread' in the early 1880s and obtained British Patent 4933 that same year. From this year he began installing light bulbs in homes and landmarks in England. His house, Underhill, Low Fell, Gateshead, was the first in the world to be lit by a lightbulb. In the early 1880s he had started his company. In 1881, the Savoy Theatre in the City of Westminster, London was lit by Swan incandescent lightbulbs, which was the first theatre, and the first public building in the world, to be lit entirely by electricity. The first street in the world to be lit by an incandescent lightbulb was Mosley Street, Newcastle upon Tyne, United Kingdom. It was lit by Joseph Swan's incandescent lamp on 3 February 1879. Thomas Edison began serious research into developing a practical incandescent lamp in 1878. Edison filed his first patent application for "Improvement in Electric Lights" on 14 October 1878. After many experiments, first with carbon in the early 1880s and then with platinum and other metals, in the end Edison returned to a carbon filament. The first successful test was on 22 October 1879, and lasted 13.5 hours. Edison continued to improve this design and by 4 November 1879, filed for a US patent for an electric lamp using "a carbon filament or strip coiled and connected ... to platina contact wires." Although the patent described several ways of creating the carbon filament including using "cotton and linen thread, wood splints, papers coiled in various ways," Edison and his team later discovered that a carbonized bamboo filament could last more than 1200 hours. In 1880, the Oregon Railroad and Navigation Company steamer, Columbia, became the first application for Edison's incandescent electric lamps (it was also the first ship to use a dynamo).

Albon Man, a New York lawyer, started Electro-Dynamic Light Company in 1878 to exploit his patents and those of William Sawyer. Weeks later the United States Electric Lighting Company was organized. This company did not make their first commercial installation of incandescent lamps until the fall of 1880, at the Mercantile Safe Deposit Company in New York City, about six months after the Edison incandescent lamps had been installed on the Columbia. Hiram S. Maxim was the chief engineer at the United States Electric Lighting Company. After the great success in the United States, the incandescent light bulb patented by Edison also began to gain widespread popularity in Europe as well; among other places, the first Edison light bulbs in the Nordic countries were installed at the weaving hall of the Finlayson's textile factory in Tampere, Finland in March 1882.

Lewis Latimer, employed at the time by Edison, developed an improved method of heat-treating carbon filaments which reduced breakage and allowed them to be molded into novel shapes, such as the characteristic "M" shape of Maxim filaments. On 17 January 1882, Latimer received a patent for the "Process of Manufacturing Carbons", an improved method for the production of light bulb filaments, which was purchased by the United States Electric Light Company. Latimer patented other improvements such as a better way of attaching filaments to their wire supports.

In Britain, the Edison and Swan companies merged into the Edison and Swan United Electric Company (later known as Ediswan, and ultimately incorporated into Thorn Lighting Ltd). Edison was initially against this combination, but Edison was eventually forced to cooperate and the merger was made. Eventually, Edison acquired all of Swan's interest in the company. Swan sold his US patent rights to the Brush Electric Company in June 1882.

The United States Patent Office gave a ruling 8 October 1883, that Edison's patents were based on the prior art of William Sawyer and were invalid. Litigation continued for a number of years. Eventually on 6 October 1889, a judge ruled that Edison's electric light improvement claim for "a filament of carbon of high resistance" was valid.

The main difficulty with evacuating the lamps was moisture inside the bulb, which split when the lamp was lit, with resulting oxygen attacking the filament. In the 1880s, phosphoric anhydride was used in combination with expensive mercury vacuum pumps. However, about 1893, Italian inventor Arturo Malignani (1865–1939), who lacked these pumps, discovered that phosphorus vapours did the job of chemically binding the remaining amounts of water and oxygen. In 1896 he patented a process of introducing red phosphorus as the so-called getter inside the bulb ), which allowed obtaining economic bulbs lasting 800 hours; his patent was acquired by Edison in 1898.

In 1897, German physicist and chemist Walther Nernst developed the Nernst lamp, a form of incandescent lamp that used a ceramic globar and did not require enclosure in a vacuum or inert gas. Twice as efficient as carbon filament lamps, Nernst lamps were briefly popular until overtaken by lamps using metal filaments.

Metal filament, inert gas

US575002A patent on 01.Dec.1897 to Alexander Lodyguine (Lodygin, Russia) describes filament made of rare metals, amongst them was tungsten. Lodygin invented a process where rare metals such as tungsten can be chemically treated and heat-vaporized onto an electrically heated thread-like wire (platinum, carbon, gold) acting as a temporary base or skeletal form. (US patent 575,002). Lodygin later sold the patent rights to GE. In 1902, Siemens developed a tantalum lamp filament that was more efficient than even graphitized carbon filaments since they could operate at higher temperature. Since tantalum metal has a lower resistivity than carbon, the tantalum lamp filament was quite long and required multiple internal supports. The metal filament gradually shortened in use; the filaments were installed with large slack loops. Lamps used for several hundred hours became quite fragile. Metal filaments had the property of breaking and re-welding, though this would usually decrease resistance and shorten the life of the filament. General Electric bought the rights to use tantalum filaments and produced them in the US until 1913.

From 1898 to around 1905, osmium was also used as a filament in lamps made by Carl Auer von Welsbach. The metal was so expensive that used lamps could be returned for partial credit. It could not be made for 110 V or 220 V so several lamps were wired in series for use on standard voltage circuits. These were primarily sold in Europe.

Tungsten filament
On 13 December 1904, Hungarian Sándor Just and Croatian Franjo Hanaman were granted a Hungarian patent (No. 34541) for a tungsten filament lamp that lasted longer and gave brighter light than the carbon filament. Tungsten filament lamps were first marketed by the Hungarian company Tungsram in 1904. This type is often called Tungsram-bulbs in many European countries. Filling a bulb with an inert gas such as argon or nitrogen slows down the evaporation of the tungsten filament compared to operating it in a vacuum. This allows for greater temperatures and therefore greater efficacy with less reduction in filament life.

In 1906, William D. Coolidge developed a method of making "ductile tungsten" from sintered tungsten which could be made into filaments while working for General Electric Company. By 1911 General Electric had begun selling incandescent light bulbs with ductile tungsten wire.

In 1913, Irving Langmuir found that filling a lamp with inert gas instead of a vacuum resulted in twice the luminous efficacy and reduced bulb blackening.

In 1917, Burnie Lee Benbow was granted a patent for the coiled coil filament, in which a coiled filament is then itself wrapped into a coil by use of a mandrel. In 1921, Junichi Miura created the first double-coil bulb using a coiled coil tungsten filament while working for Hakunetsusha (a predecessor of Toshiba). At the time, machinery to mass-produce coiled coil filaments did not exist. Hakunetsusha developed a method to mass-produce coiled coil filaments by 1936.

Between 1924 and the outbreak of the Second World War, the Phoebus cartel attempted to fix prices and sales quotas for bulb manufacturers outside of North America.

In 1925, Marvin Pipkin, an American chemist, patented a process for frosting the inside of lamp bulbs without weakening them. In 1947, he patented a process for coating the inside of lamps with silica.

In 1930, Hungarian Imre Bródy filled lamps with krypton gas rather than argon, and designed a process to obtain krypton from air. Production of krypton filled lamps based on his invention started at Ajka in 1937, in a factory co-designed by Polányi and Hungarian-born physicist Egon Orowan.

By 1964, improvements in efficiency and production of incandescent lamps had reduced the cost of providing a given quantity of light by a factor of thirty, compared with the cost at introduction of Edison's lighting system.

Consumption of incandescent light bulbs grew rapidly in the US. In 1885, an estimated 300,000 general lighting service lamps were sold, all with carbon filaments. When tungsten filaments were introduced, about 50 million lamp sockets existed in the US. In 1914, 88.5 million lamps were used, (only 15% with carbon filaments), and by 1945, annual sales of lamps were 795 million (more than 5 lamps per person per year).

Efficacy and efficiency
Less than 5% of the power consumed by a typical incandescent light bulb is converted into visible light, with most of the rest being emitted as invisible infrared radiation. Light bulbs are rated by their luminous efficacy, which is the ratio of the amount of visible light emitted (luminous flux) to the electrical power consumed. Luminous efficacy is measured in lumens per watt (lm/W).

The luminous efficiency of a source is defined as the ratio of its luminous efficacy to the maximum possible luminous efficacy, which is 683 lm/W. An ideal white light source could produce about 250 lumens per watt, corresponding to a luminous efficiency of 37%.

For a given quantity of light, an incandescent light bulb consumes more power and emits more heat than most other types of electric light. In buildings where air conditioning is used, incandescent lamps' heat output increases load on the air conditioning system. While heat from lights will reduce the need to run a building's heating system, the latter can usually produce the same amount of heat at lower cost than incandescent lights.

The chart below lists the luminous efficacy and efficiency for several types of incandescent bulb. A longer chart in luminous efficacy compares a broader array of light sources.

Color rendering
The spectrum of light produced by an incandescent lamp closely approximates that of a black body radiator at the same temperature. The basis for light sources used as the standard for color perception is a tungsten incandescent lamp operating at a defined temperature.

Light sources such as fluorescent lamps, high-intensity discharge lamps and LED lamps have higher luminous efficiency. These devices produce light by luminescence. Their light has bands of characteristic wavelengths, without the "tail" of invisible infrared emissions, instead of the continuous spectrum produced by a thermal source. By careful selection of fluorescent phosphor coatings or filters which modify the spectral distribution, the spectrum emitted can be tuned to mimic the appearance of incandescent sources, or other different color temperatures of white light. When used for tasks sensitive to color, such as motion picture lighting, these sources may require particular techniques to duplicate the appearance of incandescent lighting. Metamerism describes the effect of different light spectrum distributions on the perception of color.

Cost of lighting
The initial cost of an incandescent bulb is small compared to the cost of the energy it uses over its lifetime. Incandescent bulbs have a shorter life than most other lighting, an important factor if replacement is inconvenient or expensive. Some types of lamp, including incandescent and fluorescent, emit less light as they age; this may be an inconvenience, or may reduce effective lifetime due to lamp replacement before total failure. A comparison of incandescent lamp operating cost with other light sources must include illumination requirements, cost of the lamp and labor cost to replace lamps (taking into account effective lamp lifetime), cost of electricity used, effect of lamp operation on heating and air conditioning systems. When used for lighting in houses and commercial buildings, the energy lost to heat can significantly increase the energy required by a building's air conditioning system. During the heating season heat produced by the bulbs is not wasted, although in most cases it is more cost effective to obtain heat from the heating system. Regardless, over the course of a year a more efficient lighting system saves energy in nearly all climates.

Measures to ban use
Since incandescent light bulbs use more energy than alternatives such as CFLs and LED lamps, many governments have introduced measures to ban their use, by setting minimum efficacy standards higher than can be achieved by incandescent lamps. Measures to ban light bulbs have been implemented in the European Union, the United States, Russia, Brazil, Argentina, Canada and Australia, among others. The European Commission has calculated that the ban contributes 5 to 10 billion euros to the economy and saves 40 TWh of electricity every year, translating in CO2 emission reductions of 15 million tonnes.

Objections to banning the use of incandescent light bulbs include the higher initial cost of alternatives and lower quality of light of fluorescent lamps. Some people have concerns about the health effects of fluorescent lamps.

Efforts to improve efficacy
Some research has been carried out to improve the efficacy of commercial incandescent lamps. In 2007, General Electric announced a high efficiency incandescent (HEI) lamp project, which they claimed would ultimately be as much as four times more efficient than current incandescents, although their initial production goal was to be approximately twice as efficient. The HEI program was terminated in 2008 due to slow progress. US Department of Energy research at Sandia National Laboratories initially indicated the potential for dramatically improved efficiency from a photonic lattice filament. However, later work indicated that initially promising results were in error.

Prompted by legislation in various countries mandating increased bulb efficiency, hybrid incandescent bulbs have been introduced by Philips. The Halogena Energy Saver incandescents can produce about 23 lm/W; about 30 percent more efficient than traditional incandescents, by using a reflective capsule to reflect formerly wasted infrared radiation back to the filament from which some is re-emitted as visible light. This concept was pioneered by Duro-Test in 1980 with a commercial product that produced 29.8 lm/W. More advanced reflectors based on interference filters or photonic crystals can theoretically result in higher efficiency, up to a limit of about 270 lm/W (40% of the maximum efficacy possible). Laboratory proof-of-concept experiments have produced as much as 45 lm/W, approaching the efficacy of compact fluorescent bulbs.

Construction
Incandescent light bulbs consist of an air-tight glass enclosure (the envelope, or bulb) with a filament of tungsten wire inside the bulb, through which an electric current is passed. Contact wires and a base with two (or more) conductors provide electrical connections to the filament. Incandescent light bulbs usually contain a stem or glass mount anchored to the bulb's base that allows the electrical contacts to run through the envelope without air or gas leaks. Small wires embedded in the stem in turn support the filament and its lead wires.

An electric current heats the filament to typically 2000 to 3300 K, well below tungsten's melting point of 3695 K. Filament temperatures depend on the filament type, shape, size, and amount of current drawn. The heated filament emits light that approximates a continuous spectrum. The useful part of the emitted energy is visible light, but most energy is given off as heat in the near-infrared wavelengths.

Bulbs
Most light bulbs have either clear or coated glass. Coated glass bulbs have kaolin clay blown in and electrostatically deposited on the interior of the bulb. The powder layer diffuses the light from the filament. Pigments may be added to the clay to adjust the color of the light emitted. Kaolin diffused bulbs are used extensively in interior lighting because of their comparatively gentle light. Other kinds of colored bulbs are also made, including the various colors used for "party bulbs", Christmas tree lights and other decorative lighting. These are created by coloring the glass with a dopant; which is often a metal like cobalt (blue) or chromium (green). Neodymium-containing glass is sometimes used to provide a more natural-appearing light.

The glass bulb of a general service lamp can reach temperatures between 200 and 260 °C. Lamps intended for high power operation or used for heating purposes will have envelopes made of hard glass or fused quartz.

If a light bulb envelope leaks, the hot tungsten filament reacts with air, yielding an aerosol of brown tungsten nitride, brown tungsten dioxide, violet-blue tungsten pentoxide, and yellow tungsten trioxide that then gets deposited on the nearby surfaces or the bulb interior.

Gas fill
Most modern bulbs are filled with an inert gas to reduce evaporation of the filament and prevent its oxidation. The gas is at a pressure of about 70 kPa.

The gas reduces evaporation of the filament, but the fill must be chosen carefully to avoid introducing significant heat losses. For these properties, chemical inertness and high atomic or molecular weight is desirable. The presence of gas molecules knocks the liberated tungsten atoms back to the filament, reducing its evaporation and allowing it to be operated at higher temperature without reducing its life (or, for operating at the same temperature, prolongs the filament life). On the other hand, the presence of the gas leads to heat loss from the filament—and therefore efficiency loss due to reduced incandescence—by heat conduction and heat convection.

Early lamps used only a vacuum to protect the filament from oxygen. The vacuum increases evaporation of the filament but eliminates two modes of heat loss. Some small modern lamps use vacuum as well.

The most commonly used fills are:

 * Vacuum, used in small lamps. Provides best thermal insulation of the filament but does not protect against its evaporation. Used also in larger lamps where the outer bulb surface temperature has to be limited.
 * Argon (93%) and nitrogen (7%), where argon is used for its inertness, low thermal conductivity and low cost, and the nitrogen is added to increase the breakdown voltage and prevent arcing between parts of the filament
 * Nitrogen, used in some higher-power lamps, e.g. projection lamps, and where higher breakdown voltage is needed due to proximity of filament parts or lead-in wires
 * Krypton, which is more advantageous than argon due to its higher atomic weight and lower thermal conductivity (which also allows use of smaller bulbs), but its use is hindered by much higher cost, confining it mostly to smaller-size bulbs.
 * Krypton mixed with xenon, where xenon improves the gas properties further due to its higher atomic weight. Its use is however limited by its very high cost. The improvements by using xenon are modest in comparison to its cost.
 * Hydrogen, in special flashing lamps where rapid filament cooling is required; its high thermal conductivity is exploited here.
 * Halogen, a small amount mixed with inert gas. This is used in halogen lamps, which are a distinct type of incandescent lamp.

The gas fill must be free of traces of water, which greatly accelerates bulb blackening (see below).

The gas layer close to the filament (called the Langmuir layer) is stagnant, with heat transfer occurring only by conduction. Only at some distance does convection occur to carry heat to the bulb's envelope.

The orientation of the filament influences efficiency. Gas flow parallel to the filament, e.g., a vertically oriented bulb with vertical (or axial) filament, reduces convective losses.

The efficiency of the lamp increases with a larger filament diameter. Thin-filament, low-power bulbs benefit less from a fill gas, so are often only evacuated.

Early light bulbs with carbon filaments also used carbon monoxide, nitrogen, or mercury vapor. However, carbon filaments operate at lower temperatures than tungsten ones, so the effect of the fill gas was not significant as the heat losses offset any benefits.

Manufacturing
Early bulbs were laboriously assembled by hand. After automatic machinery was developed, the cost of bulbs fell. Until 1910, when Libbey's Westlake machine went into production, bulbs were generally produced by a team of three workers (two gatherers and a master gaffer) blowing the bulbs into wooden or cast-iron molds, coated with a paste. Around 150 bulbs per hour were produced by the hand-blowing process in the 1880s at Corning Glass Works.

The Westlake machine, developed by Libbey Glass, was based on an adaptation of the Owens-Libbey bottle-blowing machine. Corning Glass Works soon began developing competing automated bulb-blowing machines, the first of which to be used in production was the E-Machine.

Ribbon machine
Corning continued developing automated bulb-production machines, installing the Ribbon Machine in 1926 in its Wellsboro, Pennsylvania, factory. The Ribbon Machine surpassed any previous attempts to automate bulb production and was used to produce incandescent bulbs into the 21st century. The inventor, William Woods, along with his colleague at Corning Glass Works, David E. Gray, had created a machine that by 1939 was turning out 1,000 bulbs per minute.

The Ribbon Machine works by passing a continuous ribbon of glass along a conveyor belt, heated in a furnace, and then blown by precisely aligned air nozzles through holes in the conveyor belt into molds. Thus the glass bulbs or envelopes are created. A typical machine of this sort can produce anywhere from 50,000 to 120,000 bulbs per hour, depending on the size of the bulb. By the 1970s, 15 ribbon machines installed in factories around the world produced the entire supply of incandescent bulbs. The filament and its supports are assembled on a glass stem, which is then fused to the bulb. The air is pumped out of the bulb, and the evacuation tube in the stem press is sealed by a flame. The bulb is then inserted into the lamp base, and the whole assembly tested. The 2016 closing of Osram-Sylvania's Wellsboro, Pennsylvania plant meant that one of the last remaining ribbon machines in the United States was shut down.

Filament

Carbon has the highest melting point of any element, and in carbon arc lamps it had been demonstrated to produce incandescence fairly close to that of sunlight. However, carbon has a tendency to sublimate before reaching its melting point depending on pressure, which led to rapid blackening of vacuumed bulbs. The first commercially successful light bulb filaments were made from carbonized paper or bamboo. Carbon filaments have a negative temperature coefficient of resistance—as they get hotter, their electrical resistance decreases. This made the lamp sensitive to fluctuations in the power supply, since a small increase of voltage would cause the filament to heat up, reducing its resistance and causing it to draw even more power and heat even further.

Carbon filaments were "flashed" by heating in a hydrocarbon vapor (usually gasoline), to improve their strength and uniformity. Metallized or "graphitized" filaments were first heated to high temperature to transform them into graphite, which further strengthened and smoothed the filament. These filaments have a positive temperature coefficient, like a metallic conductor, which stabilized the lamps operating properties against minor variations in supply voltage.

Metal filaments were tried in 1897 and started to displace carbon starting around 1904. Tungsten has the highest available melting point, but brittleness was a big obstacle. By 1910, a process was developed by William D. Coolidge at General Electric for production of a ductile form of tungsten. The process required pressing tungsten powder into bars, then several steps of sintering, swaging, and then wire drawing. It was found that very pure tungsten formed filaments that sagged in use, and that a very small "doping" treatment with potassium, silicon, and aluminium oxides at the level of a few hundred parts per million (so-called AKS tungsten) greatly improved the life and durability of the tungsten filaments.

The predominant mechanism for failure in tungsten filaments even now is grain boundary sliding accommodated by diffusional creep. During operation, the tungsten wire is stressed under the load of its own weight and because of the diffusion that can occur at high temperatures, grains begin to rotate and slide. This stress, because of variations in the filament, causes the filament to sag nonuniformly, which ultimately introduces further torque on the filament. It is this sagging that inevitably results in a rupture of the filament, rendering the incandescent lightbulb useless.

Coiled coil filament
To improve the efficiency of the lamp, the filament usually consists of multiple coils of coiled fine wire, also known as a coiled coil. Light bulbs using coiled coil filaments are sometimes referred to as 'double-coil bulbs'. For a 60-watt 120-volt lamp, the uncoiled length of the tungsten filament is usually 22.8 in, and the filament diameter is 0.0018 in. The advantage of the coiled coil is that evaporation of the tungsten filament is at the rate of a tungsten cylinder having a diameter equal to that of the coiled coil. The coiled-coil filament evaporates more slowly than a straight filament of the same surface area and light-emitting power. As a result, the filament can then run hotter, which results in a more efficient light source while lasting longer than a straight filament at the same temperature.

Manufacturers designate different forms of lamp filament with an alphanumeric code.

Electrical filaments are also used in hot cathodes of fluorescent lamps and vacuum tubes as a source of electrons or in vacuum tubes to heat an electron-emitting electrode. When used as a source of electrons, they may have a special coating that increases electron production.

Reducing filament evaporation
During ordinary operation, the tungsten of the filament evaporates; hotter, more-efficient filaments evaporate faster. Because of this, the lifetime of a filament lamp is a trade-off between efficiency and longevity. The trade-off is typically set to provide a lifetime of 1,000 to 2,000 hours for lamps used for general illumination. Theatrical, photographic, and projection lamps may have a useful life of only a few hours, trading life expectancy for high output in a compact form. Long-life general service lamps have lower efficiency, but prior to the development of compact fluorescent and LED lamps they were useful in applications where the bulb was difficult to change.

Irving Langmuir found that an inert gas, instead of vacuum, would retard evaporation. General service incandescent light bulbs over about 25 watts in rating are now filled with a mixture of mostly argon and some nitrogen, or sometimes krypton. While inert gas reduces filament evaporation, it also conducts heat from the filament, thereby cooling the filament and reducing efficiency. At constant pressure and temperature, the thermal conductivity of a gas depends upon the molecular weight of the gas and the cross sectional area of the gas molecules. Higher molecular weight gases have lower thermal conductivity, because both the molecular weight and cross sectional area are higher. Xenon gas improves efficiency because of its high molecular weight, but is also more expensive, so its use is limited to smaller lamps.

Filament notching is due to uneven evaporation of the filament. Small variations in resistivity along the filament cause "hot spots" to form at points of higher resistivity; a variation of diameter of only 1% will cause a 25% reduction in service life. Since filament resistance is highly temperature-dependent, spots with higher temperature will have higher resistance, causing them to dissipate more energy, making them hotter – a positive feedback loop. These hot spots evaporate faster than the rest of the filament, permanently increasing the resistance at that point. The process ends in the familiar tiny gap in an otherwise healthy-looking filament.

Lamps operated on direct current develop random stairstep irregularities on the filament surface which may cut lifespan in half compared to AC operation; different alloys of tungsten and rhenium can be used to counteract the effect.

Since a filament breaking in a gas-filled bulb can form an electric arc, which may spread between the terminals and draw very heavy current, intentionally thin lead-in wires or more elaborate protection devices are therefore often used as fuses built into the light bulb. More nitrogen is used in higher-voltage lamps to reduce the possibility of arcing.

Bulb blackening
In a conventional lamp, the evaporated tungsten eventually condenses on the inner surface of the glass envelope, darkening it. For bulbs that contain a vacuum, the darkening is uniform across the entire surface of the envelope. When a filling of inert gas is used, the evaporated tungsten is carried in the thermal convection currents of the gas, and is deposited preferentially on the uppermost part of the envelope, blackening just that portion of the envelope. An incandescent lamp that gives 93% or less of its initial light output at 75% of its rated life is regarded as unsatisfactory, when tested according to IEC Publication 60064. Light loss is due to filament evaporation and bulb blackening. Study of the problem of bulb blackening led to the discovery of thermionic emission, the invention of the vacuum tube, and evaporation deposition used to make mirrors and other optical coatings.

A very small amount of water vapor inside a light bulb can significantly increase lamp darkening. Water vapor dissociates into hydrogen and oxygen at the hot filament. The oxygen attacks the tungsten metal, and the resulting tungsten oxide particles travel to cooler parts of the lamp. Hydrogen from water vapor reduces the oxide, reforming water vapor and continuing this water cycle. The equivalent of a drop of water distributed over 500,000 lamps will significantly increase darkening. Small amounts of substances such as zirconium are placed within the lamp as a getter to react with any oxygen that may bake out of the lamp components during operation.

Some old, high-powered lamps used in theater, projection, searchlight, and lighthouse service with heavy, sturdy filaments contained loose tungsten powder within the envelope. From time to time, the operator would remove the bulb and shake it, allowing the tungsten powder to scrub off most of the tungsten that had condensed on the interior of the envelope, removing the blackening and brightening the lamp again.

Halogen lamps

The halogen lamp reduces uneven evaporation of the filament and eliminates darkening of the envelope by filling the lamp with a halogen gas at low pressure, along with an inert gas. The halogen cycle increases the lifetime of the bulb and prevents its darkening by redepositing tungsten from the inside of the bulb back onto the filament. The halogen lamp can operate its filament at a higher temperature than a standard gas filled lamp of similar power without loss of operating life. Such bulbs are much smaller than normal incandescent bulbs, and are widely used where intense illumination is needed in a limited space. Fiber-optic lamps for optical microscopy is one typical application.

Incandescent arc lamps
A variation of the incandescent lamp did not use a hot wire filament, but instead used an arc struck on a spherical bead electrode to produce heat. The electrode then became incandescent, with the arc contributing little to the light produced. Such lamps were used for projection or illumination for scientific instruments such as microscopes. These arc lamps ran on relatively low voltages and incorporated tungsten filaments to start ionization within the envelope. They provided the intense concentrated light of an arc lamp but were easier to operate. Developed around 1915, these lamps were displaced by mercury and xenon arc lamps.

Power
Incandescent lamps are nearly pure resistive loads with a power factor of 1. Unlike discharge lamps or LED lamps, the power consumed is equal to the apparent power in the circuit. Incandescent light bulbs are usually marketed according to the electrical power consumed. This depends mainly on the operating resistance of the filament. For two bulbs of the same voltage, and type, the higher-powered bulb gives more light.

The table shows the approximate typical output, in lumens, of standard 120 volt incandescent light bulbs at various powers. Light output of similar 230 V bulbs is slightly less. The lower current (higher voltage) filament is thinner and has to be operated at a slightly lower temperature for the same life expectancy, which reduces energy efficiency. The lumen values for "soft white" bulbs will generally be slightly lower than for clear bulbs at the same power.

Current and resistance
The resistance of the filament is temperature dependent. The cold resistance of tungsten-filament lamps is about 1/15 the resistance when operating. For example, a 100-watt, 120-volt lamp has a resistance of 144 ohms when lit, but the cold resistance is much lower (about 9.5 ohms). Since incandescent lamps are resistive loads, simple phase-control TRIAC dimmers can be used to control brightness. Electrical contacts may carry a "T" rating symbol indicating that they are designed to control circuits with the high inrush current characteristic of tungsten lamps. For a 100-watt, 120-volt general-service lamp, the current stabilizes in about 0.10 seconds, and the lamp reaches 90% of its full brightness after about 0.13 seconds.

Safety
The filament in a tungsten light bulb is not easy to break when the bulb is cold, but filaments are more vulnerable when they are hot because the incandescent metal is less rigid. An impact on the outside of the bulb may cause the filament to break or experience a surge in electric current that causes part of it to melt or vaporize. In most modern incandescent bulbs, part of the wire inside the bulb acts like a fuse: if a broken filament produces an electrical short inside the bulb, the fusible section of wire will melt and cut the current off to prevent damage to the supply lines.

A hot glass bulb may fracture on contact with cold objects. When the glass envelope breaks, the bulb implodes, exposing the filament to ambient air. The air then usually destroys the hot filament through oxidation.

Bulb shapes
Bulb shape and size designations are given in national standards. Some designations are one or more letters followed by one or more numbers, e.g. A55 or PAR38, where the letters identify the shape and the numbers some characteristic size.

National standards such as ANSI C79.1-2002, IS 14897:2000 and JIS C 7710:1988 cover a common terminology for bulb shapes.

Common shape codes

 * General Service/General Lighting Service (GLS)
 * Light emitted in (nearly) all directions. Available either clear or frosted.
 * Types: General (A), elliptical (E), mushroom (M), sign (S), tubular (T)
 * 120 V sizes: A17, 19 and 21
 * 230 V sizes: A55 and 60

 * High Wattage General Service
 * Lamps greater than 200 watts.
 * Types: Pear-shaped (PS)

 * Decorative
 * lamps used in chandeliers, etc. Smaller candle-sized bulbs may use a smaller socket.
 * Types: candle (B), twisted candle, bent-tip candle (CA & BA), flame (F), globe (G), lantern chimney (H), fancy round (P)
 * 230 V sizes: P45, G95

 * Reflector (R): Reflective coating inside the bulb directs light forward. Flood types (FL) spread light. Spot types (SP) concentrate the light. Reflector (R) bulbs put approximately double the amount of light (foot-candles) on the front central area as General Service (A) of same wattage.
 * Types: Standard reflector (R), bulged reflector (BR), elliptical reflector (ER), crown-silvered
 * 120 V sizes: R16, 20, 25 and 30
 * 230 V sizes: R50, 63, 80 and 95

 * Parabolic aluminized reflector (PAR)
 * Parabolic aluminized reflector (PAR) bulbs control light more precisely. They produce about four times the concentrated light intensity of general service (A), and are used in recessed and track lighting. Weatherproof casings are available for outdoor spot and flood fixtures.
 * 120 V sizes: PAR 16, 20, 30, 38, 56 and 64
 * 230 V sizes: PAR 16, 20, 30, 38, 56 and 64
 * Available in numerous spot and flood beam spreads. Like all light bulbs, the number represents the diameter of the bulb in $1/8$ of an inch. Therefore, a PAR 16 is 2 in in diameter, a PAR 20 is 2.5 in in diameter, PAR 30 is 3.75 in and a PAR 38 is 4.75 in in diameter.

 * Multifaceted reflector (MR)
 * Multifaceted reflector bulbs are usually smaller in size and run at a lower voltage, often 12 V.

 * HIR/IRC: "HIR" is a GE designation for a lamp with an infrared reflective coating. Since less heat escapes, the filament burns hotter and more efficiently. The Osram designation for a similar coating is "IRC".

Lamp bases

Large lamps may have a screw base or a bayonet base, with one or more contacts on the base. The shell may serve as an electrical contact or only as a mechanical support. Bayonet base lamps are frequently used in automotive lamps to resist loosening by vibration. Some tubular lamps have an electrical contact at either end. Miniature lamps may have a wedge base and wire contacts, and some automotive and special purpose lamps have screw terminals for connection to wires. Very small lamps may have the filament support wires extended through the base of the lamp for connections. A bipin base is often used for halogen or reflector lamps.

In the late 19th century, manufacturers introduced a multitude of incompatible lamp bases. General Electric's "Mazda" standard base sizes were soon adopted across the US.

Lamp bases may be secured to the bulb with a cement, or by mechanical crimping to indentations molded into the glass bulb.

Lamps intended for use in optical systems have bases with alignment features so that the filament is positioned accurately within the optical system. A screw-base lamp may have a random orientation of the filament when the lamp is installed in the socket.

Contacts in the lightbulb socket allow the electric current to pass through the base to the filament. The socket provides electrical connections and mechanical support, and allows changing the lamp when it burns out.

Light output and lifetime
Incandescent lamps are very sensitive to changes in the supply voltage. These characteristics are of great practical and economic importance.

For a supply voltage V near the rated voltage of the lamp:

 * Light output is approximately proportional to V3.4
 * Power consumption is approximately proportional to V1.6
 * Lifetime is approximately proportional to V−16
 * Color temperature is approximately proportional to V0.42

A 5% reduction in voltage will double the life of the bulb, but reduce its light output by about 16%. Long-life bulbs take advantage of this trade-off in applications such as traffic signal lamps. Since electric energy they use costs more than the cost of the bulb, general service lamps emphasize efficiency over long operating life. The objective is to minimize the cost of light, not the cost of lamps. Early bulbs had a life of up to 2500 hours, but in 1924 the Phoebus cartel agreed to limit life to 1000 hours. When this was exposed in 1953, General Electric and other leading American manufacturers were banned from limiting the life.

The relationships above are valid for only a few percent change of voltage around standard rated conditions, but they indicate that a lamp operated at low voltage could last much longer than at rated voltage, albeit with greatly reduced light output. The "Centennial Light" is a light bulb that is accepted by the Guinness Book of World Records as having been burning almost continuously at a fire station in Livermore, California, since 1901. However, the bulb emits the equivalent light of a four watt bulb. A similar story can be told of a 40-watt bulb in Texas that has been illuminated since 21 September 1908. It once resided in an opera house where notable celebrities stopped to take in its glow, and was moved to an area museum in 1977.

Photoflood lamps used for photographic lighting favor light output over life, with some lasting only two hours. The upper temperature limit for the filament is the melting point of the metal. Tungsten is the metal with the highest melting point, 3695 K. A 50-hour-life projection bulb, for instance, is designed to operate only 50 °C below that melting point. Such a lamp may achieve up to 22 lumens per watt, compared with 17.5 for a 750-hour general service lamp.

Lamps of the same power rating but designed for different voltages have different luminous efficacy. For example, a 100-watt, 1000 hour, 120-volt lamp will produce about 17.1 lumens per watt. A similar lamp designed for 230 V would produce only around 12.8 lumens per watt, and one designed for 30 volts (train lighting) would produce as much as 19.8 lumens per watt. Lower voltage lamps have a thicker filament, for the same power rating. They can run hotter for the same lifetime before the filament evaporates.

The wires used to support the filament make it mechanically stronger, but remove heat, creating another tradeoff between efficiency and long life. Many general-service 120-volt lamps use no additional support wires, but lamps designed for "rough service" or "vibration service" may have as many as five. Low-voltage lamps have filaments made of heavier wire and do not require additional support wires.

Very low voltages are inefficient since the lead wires would conduct too much heat away from the filament, so the practical lower limit for incandescent lamps is 1.5 volts. Very long filaments for high voltages are fragile, and lamp bases become more difficult to insulate, so lamps for illumination are not made with rated voltages over 300 volts. Some infrared heating elements are made for higher voltages, but these use tubular bulbs with widely separated terminals.

title: Incandescent light bulb


text:
Vesta

Vesta may refer to:

Brands and products

 * Lada Vesta, a car from Russian car manufacturer AVTOVAZ
 * Swan Vesta (began 1883), a brand of matches
 * Vesta case, metal containers for matches (which were previously called vestas)
 * Vesta, a freeze-dried meal brand launched in the United Kingdom by Batchelors in the early 1970s, and now owned by Premier Foods.

Fiction and mythology

 * Sailor Vesta, a character in Sailor Moon
 * Vesta (Marvel Comics), a Marvel Comics character
 * Vesta (mythology), Roman goddess of the hearth and home

People

 * Vesta Stoudt (1891–1966), factory worker during Second World War known for her letter to President Franklin D. Roosevelt suggesting the use of adhesive tape to improve ammunition boxes, leading to duct tape
 * Vesta (1957–2011), stage name of American recording artist Vesta Williams

Music

 * Vesta (album), 1986 album by Vesta Williams
 * Vesta 4 U, 1988 album by Vesta Williams
 * Vesta, a 2008 rock band made up of former members of The Juliana Theory

Places

 * Monte Vesta, Lombardy, Italy
 * Temple of Vesta, Rome, Italy
 * Vesta Nunataks, Alexander Island, Antarctica

Canada

 * Vesta Creek (Alberta), a stream in northern Alberta
 * Vesta Creek (Ontario), a stream in Bruce County, Ontario
 * Vesta, a dispersed rural community in the municipality of Brockton, Bruce County, Ontario

United States

 * Vesta, Arkansas
 * Vesta, Georgia
 * Vesta, Minnesota
 * Vesta, Nebraska
 * Vesta, Virginia
 * Vesta, Washington

Science and technology

 * 4 Vesta, an asteroid
 * Vesta family, group of asteroids that includes 4 Vesta
 * Vesta (rocket), A French sounding rocket
 * The Vesta parallel file system, a precursor of IBM's GPFS
 * Vesta (software configuration management) (developed 1993), advanced configuration management system released by Compaq
 * Vesta longifolia, a species of flowering plant in the family Araceae
 * Vestas (founded 1945), Danish manufacturer of wind turbines

Other uses

 * IF Vesta, sports club in Uppsala, Sweden established in 1911
 * SS Vesta (1853–1875), a French iron screw steamer
 * Vesta (name), feminine given name
 * Vesta Rowing Club (founded 1870), a rowing club based in London, England
 * Vesta Battery Corporation (1897–1964), an automobile battery company
 * Vesta, a genus of flowering plant, sole species Vesta longifolia

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Vesta


text:
List of minor-planet groups

A minor-planet group is a population of minor planets that share broadly similar orbits. Members are generally unrelated to each other, unlike in an asteroid family, which often results from the break-up of a single asteroid. It is customary to name a group of asteroids after the first member of that group to be discovered, which is often the largest.

Groups out to the orbit of Earth
There are relatively few asteroids that orbit close to the Sun. Several of these groups are hypothetical at this point in time, with no members having yet been discovered; as such, the names they have been given are provisional.
 * Vulcanoid asteroids are hypothetical asteroids that orbit entirely within the orbit of Mercury (have an aphelion of less than 0.3874 AU). A few searches for vulcanoids have been conducted but none have been discovered so far.
 * ꞌAylóꞌchaxnim asteroids (previously named Vatira) are asteroids that orbit entirely within the orbit of Venus (have an aphelion of less than 0.718 AU)., one such asteroid is known: 594913 ꞌAylóꞌchaxnim.
 * Atira asteroids (Apohele; Interior-Earth Objects) are a small group of known asteroids whose aphelion is less than 0.983 AU, meaning they orbit entirely within Earth's orbit. The group is named after its first confirmed member, 163693 Atira., the group consists of 22 members, 6 of which are numbered.
 * Mercury-crosser asteroids having a perihelion smaller than Mercury's 0.3075 AU.
 * Venus-crosser asteroids having a perihelion smaller than Venus's 0.7184 AU. This group includes the above Mercury-crossers (if their aphelion is greater than Venus's perihelion. All known Mercury crossers satisfy this condition except ꞌAylóꞌchaxnim, which has an aphelion smaller than Venus's perihelion and a perihelion slightly smaller than Mercury's aphelion).
 * Earth-crosser asteroids having a perihelion smaller than Earth's 0.9833 AU. This group includes the above Mercury- and Venus-crossers, apart from the Apoheles. They are also divided into the
 * Aten asteroids having a semi-major axis less than 1 AU, named after 2062 Aten.
 * Apollo asteroids having a semi-major axis greater than 1 AU, named after 1862 Apollo.
 * Arjuna asteroids are somewhat vaguely defined as having orbits similar to Earth's; i.e. with an average orbital radius of around 1 AU and with low eccentricity and inclination. Due to the vagueness of this definition some asteroids belonging to the Atira, Amor, Apollo or Aten groups can also be classified as Arjunas. The term was introduced by Spacewatch and does not refer to an existing asteroid; examples of Arjunas include 1991 VG.
 * Earth trojans are asteroids located in the Earth–Sun Lagrangian points and . Their location in the sky as observed from Earth's surface would be fixed at about 60 degrees east and west of the Sun, and as people tend to search for asteroids at much greater elongations few searches have been done in these locations. The only known Earth trojans are  and.
 * Near-Earth asteroids is a catch-all term for asteroids whose orbit closely approaches that of Earth. It includes almost all of the above groups, as well as the Amor asteroids.

Groups out to the orbit of Mars

 * The Amor asteroids, named after 1221 Amor, are near-Earth asteroids that are not Earth-crossers, having a perihelion just outside the Earth's orbit.
 * Mars-crosser asteroids have orbits that cross that of Mars, but do not necessarily closely approach the Earth's.
 * Mars trojans follow or lead Mars on its orbit, at either of the two Lagrangian points 60° ahead or behind . As of November 2020, nine are known. The largest appears to be 5261 Eureka.
 * Many of the Earth-, Venus-, and Mercury-crosser asteroids have aphelia greater than 1 AU.

The asteroid belt
Kirkwood Gaps.svg showing the four most prominent Kirkwood gaps and a possible division into inner, middle and outer main-belt asteroids:

]]

The overwhelming majority of known asteroids have orbits lying between the orbits of Mars and Jupiter, roughly between 2 and 4 AU. These could not form a planet due to the gravitational influence of Jupiter. Jupiter's gravitational influence, through orbital resonance, clears Kirkwood gaps in the asteroid belt, first recognised by Daniel Kirkwood in 1874.

The region with the densest concentration (lying between the Kirkwood gaps at 2.06 and 3.27 AU, with eccentricities below about 0.3, and inclinations smaller than 30°) is called the asteroid belt. It can be further subdivided by the Kirkwood Gaps into the:
 * Inner asteroid belt, inside of the strong Kirkwood gap at 2.50 AU due to the 3:1 Jupiter orbital resonance. The largest member is 4 Vesta.
 * It apparently also includes a group called the main-belt I asteroids which have a semi-major axis between 2.3 AU and 2.5 AU and an inclination of less than 18°.
 * Middle (or intermediate) asteroid belt, between the 3:1 and 5:2 Jupiter orbital resonances, the latter at 2.82 AU. The largest member is Ceres. This group is apparently split into the:
 * Main-belt IIa asteroids which have a semi-major axis between 2.5 AU and 2.706 AU and an inclination less than 33°.
 * Main-belt IIb asteroids which have a semi-major axis between 2.706 AU and 2.82 AU and an inclination less than 33°.
 * Outer asteroid belt between the 5:2 and 2:1 Jupiter orbital resonances. The largest member is 10 Hygiea. This group is apparently split into the:
 * Main-belt IIIa asteroids which have a semi-major axis between 2.82 AU and 3.03 AU, an eccentricity less than .35, and an inclination less than 30°.
 * Main-belt IIIb asteroids which have a semi-major axis between 3.03 AU and 3.27 AU, an eccentricity less than .35, and an inclination less than 30°.

Other groups out to the orbit of Jupiter
There are a number of more or less distinct asteroid groups outside the asteroid belt, distinguished either by mean distance from the Sun, or particular combinations of several orbital elements:
 * The Hungaria asteroids, with a mean orbital radius between 1.78 AU and 2 AU, an eccentricity less than 0.18, and inclination between 16° and 34°. Named after 434 Hungaria, these are just outside Mars's orbit, and are possibly attracted by the 9:2 Jupiter resonance or the 3:2 Mars resonance.
 * The Phocaea asteroids, with a mean orbital radius between 2.25 AU and 2.5 AU, an eccentricity greater than 0.1, and inclination between 18° and 32°. Some sources group the Phocaeas asteroids with the Hungarias, but the division between the two groups is real and caused by the 4:1 resonance with Jupiter. Named after 25 Phocaea.
 * The Alinda asteroids have a mean orbital radius of 2.5 AU and an eccentricity between 0.4 and 0.65 (approximately). These objects are held by the 3:1 resonance with Jupiter and a 4:1 resonance with Earth. Many Alinda asteroids have perihelia very close to Earth's orbit and can be difficult to observe for this reason. Alinda asteroids are not in stable orbits and eventually will collide either with Jupiter or terrestrial planets. Named after 887 Alinda.
 * The Pallas family asteroids have a mean orbital radius between 2.7 and 2.8 AU and an inclination between 30° and 38°. Named after 2 Pallas.
 * The Griqua asteroids have an orbital radius between 3.1 AU and 3.27 AU and an eccentricity greater than 0.35. These asteroids are in stable 2:1 libration with Jupiter, in high-inclination orbits. There are about 5 to 10 of these known so far, with 1362 Griqua and 8373 Stephengould the most prominent.
 * The Cybele asteroids have a mean orbital radius between 3.27 AU and 3.7 AU, an eccentricity less than 0.3, and an inclination less than 30°. This group appears to cluster around the 7:4 resonance with Jupiter. Named after 65 Cybele.
 * Hilda asteroids have a mean orbital radius between 3.7 AU and 4.2 AU, an eccentricity greater than 0.07, and an inclination less than 20°. These asteroids are in a 3:2 resonance with Jupiter. Named after 153 Hilda.
 * The Thule asteroids are in a 4:3 resonance with Jupiter and the group is known to consist of 279 Thule,, and.
 * The Jupiter trojans have a mean orbital radius between 5.05 AU and 5.4 AU, and lie in elongated, curved regions around the two Lagrangian points 60° ahead and behind of Jupiter. The leading point,, is called the Greek camp and the trailing point is called the Trojan camp, after the two opposing camps of the legendary Trojan War; with one exception apiece, objects in each node are named for members of that side of the conflict. 617 Patroclus in the Trojan camp and 624 Hektor in the Greek camp are "misplaced" in the enemy camps.

There is a forbidden zone between the Hildas and the Trojans (roughly 4.05 AU to 4.94 AU). Aside from 279 Thule and 228 objects in mostly unstable-looking orbits, Jupiter's gravity has swept everything out of this region.

Groups beyond the orbit of Jupiter
Most of the minor planets beyond the orbit of Jupiter are believed to be composed of ices and other volatiles. Many are similar to comets, differing only in that the perihelia of their orbits are too distant from the Sun to produce a significant tail.
 * The Damocloid asteroids, also known as the "Oort cloud group," are named after 5335 Damocles. They are defined to be objects that have "fallen in" from the Oort cloud, so their aphelia are generally still out past Uranus, but their perihelia are in the inner Solar System. They have high eccentricities and sometimes high inclinations, including retrograde orbits. The definition of this group is somewhat fuzzy, and may overlap significantly with comets.
 * The Centaurs have a mean orbital radius roughly between 5.4 AU and 30 AU. They are currently believed to be trans-Neptunian objects that "fell in" after encounters with gas giants. The first of these to be identified was 2060 Chiron (944 Hidalgo was discovered before, but not identified as a distinct orbital class).

Groups at or beyond the orbit of Neptune

 * The Neptune trojans as of February 2020 consist of 29 objects. The first one to be discovered was.
 * Trans-Neptunian objects (TNOs) are anything with a mean orbital radius greater than 30 AU. This classification includes the Kuiper-belt objects (KBOs), the scattered disc, and the Oort cloud.
 * Kuiper-belt objects extend from roughly 30 AU to 50 AU and are broken into the following subcategories:
 * Resonant objects occupy orbital resonances with Neptune, excluding the 1:1 resonance of the Neptune trojans.
 * Plutinos are by far the most common resonant KBOs and are in a 2:3 resonance with Neptune, just like Pluto. The perihelion of such an object tends to be close to Neptune's orbit (much as happens with Pluto), but when the object comes to perihelion, Neptune alternates between being 90 degrees ahead of and 90 degrees behind of the object, so there's no chance of a collision. The MPC defines any object with a mean orbital radius between 39 AU and 40.5 AU to be a plutino. 90482 Orcus and 28978 Ixion are among the brightest known.
 * Other resonances. There are several known objects in the 1:2 resonance, dubbed twotinos, with a mean orbital radius of 47.7 AU and an eccentricity of 0.37. There are several objects in the 2:5 (mean orbital radius of 55 AU), 4:7, 4:5, 3:10, 3:5, and 3:4 resonances, among others. The largest in the 2:5 resonance is, and the largest in the 3:10 resonance is 225088 Gonggong.
 * Classical Kuiper-belt objects, also known as cubewanos (after 15760 Albion, which had the provisional designation from its 1992 discovery to its 2018 naming), have a mean orbital radius between approximately 40.5 AU and 47 AU. Cubewanos are objects in the Kuiper belt that didn't get scattered and didn't get locked into a resonance with Neptune. The largest is.
 * Scattered disc objects (SDOs) typically have, unlike cubewanos and resonant objects, high-inclination, high-eccentricity orbits with perihelia that are still not too far from Neptune's orbit. They are assumed to be objects that encountered Neptune and were "scattered" out of their originally more circular orbits close to the ecliptic. The most massive known dwarf planet, Eris, belongs to this category.
 * Detached objects (extended scattered disk) with generally highly elliptical, very large orbits of up to a few hundred AU and a perihelion too far from Neptune's orbit for any significant interaction to occur. A more typical member of the extended disk is.
 * Sednoids have perihelia very far removed from the orbit of Neptune. This group is named after the best-known member, 90377 Sedna. As of 2020, only 4 objects in this category have been identified, but it is suspected that there are many more.
 * The Oort cloud is a hypothetical cloud of comets with a mean orbital radius between approximately 50,000 AU and 100,000 AU. No Oort-cloud objects have been detected; the existence of this classification is only inferred from indirect evidence. Some astronomers have tentatively associated 90377 Sedna with the inner Oort cloud.

title: List of minor-planet groups


text:
Talk:Logarithmic integral function

Starts at?
Do you want Li(x) to be the integral that starts at 0, or the integral that starts at 2? You use two different definitions in this article. Furthermore, for which values of x is Li(x) defined? AxelBoldt, Tuesday, April 2, 2002

 * See renewed article for improvements. I know it is not perfect. I still have to do more on a definition range of Li(x). Please be patient :-) Perhaps nice graph would solve the problem? Your futher remarks are very wellcome. And we should start to correct also Eric Weisstein's math pages because he almost does not use any definition ranges or does he? --XJam [2002.04.02] 2 Tuesday (0).

 * No, he often glosses over these things. Yes, a graph of li(x) would be nice. I added the ranges and corrected some formulas. I have a question about:

 * π(n) = ∑ undefined∞ μ(m)/m ∫ μn 1/ ln t dt,

 * where μ(m) is Möbius function.

 * Where did you find this formula? AxelBoldt

 * You can find this form of prime number theorem at http://mathworld.wolfram.com/SoldnersConstant.html.
 * I don't trust that formula; it looks wrong to me. Weisstein has lots of mistakes. Can you find it somewhere else?
 * This is a hard field and I doubt if we can check a formula at a glance. I'll go finding it.
 * This is Ramanujan's result and Ramanujan was known that he did not understand math in full, he, he. The same thing happend when Hawking corrected Zel'dovich and Starobinsky's work on Hawking radiation of black holes or something like that not to speak about Feynman. Who blames Gauss that he was too young to give a second estimation for π(ξ)? I would like also to clarify some of the following things if it is posible.
 * ÄCHTUNG (= outlawry (Small word game on famous German attention))
 * 1// Nice you've put some definition ranges in equations. As I am partly physicist it shows that I am not as rigorous as mathematician - but I think this is not some special fault. At first you argued about two different definitions of li(x) and Li(ξ) and afterward you had thrown out some further explanations, mainly concerning famous Li(ξ).
 * I saw somewhere that li(x) and Li(x) are used interchangeably, and so I didn't want to confuse the issue. The "logarithmic integral" as such is always the integral that starts at 0, with Cauchy principal value. We can even use this version in the prime number theorem; it is slighly more accurate than using the integral that starts at 2.
 * 2// If a function is non elemental - isn't this important? Should we searh for this property in appropriate article function. I doubt there's an explanation for this. (I haven't checked).
 * Yup, I put that back in.
 * 3// I've noticed you don't like mathematical terms to be named in two or more ways (i.e. Euler constant and so on). What approach should we use here? You left for example opened naming Ramanujan-Soldner constant but mostly is used Soldner's one.
 * If there are several names for a concept, you describe those several names on the concept's page, but not on every page that links to the concept.
 * Yes this was my intention because one still have to do a link to that particular constant if that is desired.
 * 4// It is nice to know that some terms in li(eu) and li(xm) must have absolute values (i.e. ln| ln x|). Where can we find this strictly terms of this kind of series?
 * It was mistake in Weisstein. You need the absolute value.
 * I've got them from Bronstein and Semendyayev not from Eric's sources... But I must add that many pure mathematicians give links and references to Eric's pages and they are not wrong all I guess. I like a form of that pages (do you know anyone better). Wikipedia is still in nappies for math.
 * 5//> For x > 1 in a point t=1 this integral diverges. < What is wrong with this one? Yes, this is just main definition range. It is not a definition range in full, because an integral is defined also for 0 < x < 1.
 * Nothing wrong with this. It's still there, just a bit reformulated.
 * 6// OK. We put out the entire connection with Li(ξ) and π(ξ). Connection lost. We must see prime number theorem and back forth. But why we have to throw away this Li(x) = li(x) - li(2)? This is an important property of Li(ξ), isnt it? This is also important > logarithmic integral is defined with no Cauchy's principal value so that Li(2) = 0 <
 * As I said above, we can use li(x) in the prime number theorem (which is what Gauss did in fact).
 * Yes, but we are not all Gausses. This is fine particular case. I have seen mostly Li(ξ) in number theory. Both integrals do not map π(ξ) in a whole, so there's only a small difference - but it is good to know it.
 * 7// I've written > Thus we can rewrite Cpv ∫0x 1/ln t dt by ∫μx 1/ln t dt in x>1. < I think this is very wide-ranging Ramanujan's adoption and I don't know why this can't be in article... You just put another definition for Cauchy's principal value.
 * My version of the article explains what the Cauchy principal value is, while your version simply says "take the Cauchy principal value" without explaining it.
 * But - as you said - this must be explained in other article (concept's page)! Yes, this was mentioned again to put related stuff out there but for first view is good to have with. In that way I am freely to go and write Ramanujan-Soldner-Stohacky's constant everywhere I want and back on to ∞. I have a question about this. How should be articles in Wikipedia be atomized or be structured? Should they be like Cantor's dust or should they look like a monster group? Think on physics. If atoms and 'superstrings' or even numbers were slightly different, we wouldn't be here to argue about their structures and such. What to explain and what to mentioned? I prefer more things to mention than nothing or few.
 * 8// I was explaining nothing else but terms li(x), Li(ξ), ∫μx with Möbius function μ(n) or with prime number theorem. I would like to put these things back in the article but the thin red line which separates an article from encyclopedia's term is far from my sight...
 * As I said above, I don't trust this formula. I'm sure there is a formula like that by Ramanujan, but Weisstein's version is wrong.
 * 9// Nobody didn't tell me I can't use binary 'semi' operator ≡ in Wikipedia... Nobody told me I can't bold terms as li(x), Li(x) in definitions. Someone told me (I think it was Zundark) we can't use colors in Wikipedia.
 * Why do you want ≡ instead of the simple "="?
 * Because it is quite informational. It shows an equation to be a definition. Think on pascal-like unitary operator for setting values to variables (:=). If you think that we don't need ≡, we simply don't need it.
 * 10// I have a lot of will for mathematics and related things but now I am really afraid to say anything that I know or that I don't. I still have some things to say but I'm too tired to do so. I would like to know what would be if Ramanujan would live longer or if he and Gauss would have personal computers. (Perhaps I'll deside to stick with plain TeX and native stupidity) :-) --
 * 11//Axel, is anything of above posible. Do I need any confirmation from Wikipedian collegiate body? I would like to hear someone else's opinion too. What is really worth if someone (you) corrects the understanding of something for 20% but he reduces it by 21%. This is like going two steps forward and one backward. Chaos and blirt. --XJam [2002.04.03] 3 Wednesday (0).
 * Why do you always get so irritated about every little thing of you I edit? This editing of each other's material is the name of the game after all. AxelBoldt
 * I guess I have to get used on it. Another question comes to me about this. :-) I know Germans are very precise people. It is not commonly known that Slovenes are too. :-) (Pst, perhaps even more than Germans, ha, ha, but they are outnumbered). I wonder about another property of human activities. Which nation is the most methodical or systematic one? It would be nice to know. If there is one in the first place. I am not irritated (perhaps it looks like). I just have my own way of putting things outta me. And I know I am not alone. We are not equal at all that is for shure. And to paraphrase Joseph Hill in the end: there are three sides of mathematical truth... Best regards. --XJam [2002.04.04] 4 Thur's day (0).

Why does the formula for the growth behavior for x->\infty use \Theta rather than O? Wilke 19:14, 11 May 2004 (UTC)

I moved this here and made logarithmic integral a disambiguation page since there is an entirely different meaning to the word. Gene Ward Smith 02:44, 16 Feb 2005 (UTC)

Math noob question: can the logarithmic integral be evaluated in closed form? I would like to see this question answered in the article. Thanks! Greg (theytsejam) 20:25, 17 June 2007 (UTC)

Should there be a bit more on the connection between this function and the PNT? For example, the error difference, and Littlewood violations? My 2 Cents' Worth (talk) 13:24, 21 February 2011 (UTC)

ali(x)?
I was looking for the the inverse function of the logarithmic integral function, ali(x). Is there a reason that it is not mention here? John W. Nicholson (talk) 01:39, 12 April 2014 (UTC)

Li (x)-pi (x)=O(sqrt {x}\log x)
This bound is referenced from Abramowitz and Stegun. The new digital version DLMF dated 12/15/2019 shows the best bound as:

 * π(x)−li(x)|= O(x *exp(−d(lnx)^3/5 * (lnlnx)^(−1/5))).

I have no familiarity otherwise so I cannot comment.--Billymac00 (talk) 03:44, 28 December 2019 (UTC)

Does this belong here?
The logarithmic integral is defined as either ("American" definition starting at 0, for which there is a singularity at $$x$$ = 1)

 * $$\operatorname{li}(x) := \lim_{\eta \to 0^+} \left( \int_{0}^{1-\eta} + \int_{1+\eta}^{x} \right) \frac{du}{\log u},$$

or ("European" definition starting at 2)

 * $$\operatorname{li}(x) := \int_{2}^{x} \frac{du}{\log u},$$ 49.185.41.241 (talk) 12:45, 29 June 2022 (UTC)

title: Talk:Logarithmic integral function


text:
CMO

CMO may refer to:

Business

 * Chief marketing officer
 * Chief medical officer, the senior government official designated head of medical services
 * Chief merchandising officer
 * Collateralized mortgage obligation, a type of complex debt security
 * Contract manufacturing organization, a pharmaceutical manufacturing outsourcing organization
 * Collective management organization, an organisation that manages intellectual property rights, like copyrights, on behalf of rightsholders.

Organizations

 * Chicago, St. Paul, Minneapolis and Omaha Railway
 * Chi Mei Optoelectronics, producer of TFT LCD panels
 * Citizens' Municipal Organisation, Australian political organisation
 * Commodore's Messenger Organization, a high-ranking group with the Scientology Sea Organisation
 * Congressional caucus or congressional member organization

Science and engineering

 * Central massive object at the center of a galaxy, either a supermassive black hole, or a nuclear star cluster
 * Cetyl myristoleate, a type of fatty acid ester
 * Corticosterone 18-monooxygenase, an enzyme involved in steroid hormone metabolism
 * Cubic mile of oil, a global-scale measure of energy, roughly equal to the amount of oil consumed worldwide each year
 * Comfort measures only, a medical abbreviation for an end-of-life care instruction

Other uses

 * Canadian Mathematical Olympiad
 * Cyprus Mathematical Olympiad, organised by the Cyprus Mathematical Society
 * CAMPUS Magazine Online
 * Check Mii Out, channel for the Wii
 * Civil-military operations, activities of a military force
 * Command: Modern Operations, commercial wargaming software

title: CMO


text:
User talk:Jimbo Wales/Statement of principles

Early discussion
Could you replace NPOV by the more meaningful phrase "neutral point of view". I think this makes it more readable and usable for the rest of us.

Moving right along. ..

Item 2 states (in pertinent part):

"Newcomers are always to be welcomed. There must be no cabal, there must be no elites, there must be no hierarchy or structure which gets in the way of this openness to newcomers."

Item 5 states (in pertinent part):

"Anyone who wants to use our content in a closed proprietary manner must be challenged. We must adhere very strictly to both the letter and spirit of the license."

Item 7 states (in pertinent part):

"Anyone with a beef should be treated with the utmost respect and dignity. They should be encouraged constantly to present their problems in a constructive way in the open forum of the mailing list."

I've been involved in a number of purportedly open communities, and I've done my best to extol the virtues of the above-narrated principles in my role as one of the designated leaders of those communities. However, whenever openness really seems to matter, I have consistently encountered rhetoric in re the "practical limitations" of openness. Thankfully, Wikipedia seems to be free of this rhetoric. Is this rhetoric-free environment simply the genius of the Wikipedia community? Or are there procedural barriers in place to prevent charismatic tyrants from seizing control of Wikipedia?

Netesq

 * To toot my own horn, part of the reason for the clarity of the statement of principles is from pressure I brought to bear. I was an ODP editor who discovered the actual nature of the ODP when I challenged its structures of control. There are still some points of danger on Wikipedia, the number one probably being the mailing list and the current conception of NPOV being something that is achievable (see User:The Cunctator/How to build Wikipedia, which is the rah-rah version of User:The Cunctator/How to destroy Wikipedia, which had been a rant). One point of improvement that hasn't happened yet but supposedly will is an automatic process of granting people who have edited at Wikipedia for a while the "sysop" privileges. Right now it's done at the behest of the mailing list, which is a problem.

 * To more directly answer your question, the procedural barrier is the totally plastic nature of WikiWiki. I think the best explication of that phenomenon is Sunir Shah's pages on SoftSecurity.

 * And the final answer is that Jimbo Wales really gets how to run a project like this.--The Cunctator

In number 3 of your principles you speak of the open "and_viral_nature" of the GNU FDL license. Is the word "viral" a typographical error when you meant something else? It's hard to imagine that you would want the site full of viruses, but I'm not sure what you intended. Eclecticology

"viral" refers to anything, especially anything memetic, that propagates itself by attaching itself to something else. The GNU FDL is desirable precisely *because* it is viral, which in the context of a license means that it applies to derivative works, which are "infected" by the requirement to re-integrate changes deemed desirable by any party down the line. I.e. if you go to any derivative of the wikipedia whatsoever, you should be able, thanks to this "viral" license, to crib its text directly into the original wiki or any other wiki... without the "viral" license variant terms can apply to the forks, derivative works can be controlled commercially, etc. It's exactly the right term.
 * Thanks for the explanation. I even think that I understand what you are saying, and have no problem with the underlying philosophy.  My concern is probably more related to the power of words.  In the public mind "virus" and "viral" have such overwhelmingly negative connotations (as distinct from denotations) that the simple appearance of the word can be a cause for alarm and concern.  I'm confident that I'm not the only one that has required an explanation.
 * I can nevertheless envision a public health parallel to the subject where perhaps the word "innoculated" is more appropriate than "infected". The medical innoculation too is based on an adapted biological virus.  Eclecticology
 * we should be highlighting rather than avoiding those parallels - for instance "genetic engineering" is a euphemism for "creating an artificial viral strand of DNA and injecting it semi-randomly into a genome by various mechanical means". I outlined the exact value  of the GNU FDL in viral license - note that fear of the "virus" created the open source movement, which lacks the viral feature - and is thus seriously and fatally broken.  THe viral feature is what matters about the GPL - it could have quite restrictive pricing, etc.,but as long as the terms were uniform it would work to unify a base of contributors.  Open source is dangerous crap - simply spews bad code and bad copies with all kinds of separate licensing terms applying to its dead and dying body parts...

Open source is dangerous crap - Now who is being ideological now 24? -maveric149
 * I didn't intend to troll for another "war of 24" when I started this discussion. I was only trying to see if one word was a typo.  Now I know it wasn't.  Instead the conversation became infected by a lawyer virus.  The real underlying question is whether we believe knowledge to be public or proprietary.  The subtleties that distinguish viral licenses and open source seem more and more like arcane lawyer talk suited for ecclesiastical councils.  What matters more to me is limiting the right of corporatocracy to control knowledge. Eclecticology

I noted, in passing, your endorsement (in the WikiEN-l Archive) of some kind of mechanism for delayed visibility/effectiveness of edits. I'm glad to have seen this. It clearly contributes to the factors that make me keep the hope for Wikipedia. I returned to Wikipedia in April, and since then my impression (as stated in April) have been reinforced. The invitation to all readers to correct and amend articles is not necessarily injured by a delayed visibility. /Tuomas 19:27, 20 Nov 2004 (UTC)

Rule by consensus
Editing Wikipedia lately isn't as pleasurable as it once was. The shouting, wikilawyering and mob rule seem to have oughtweighed NPOV and rule by consensus. Semi-policy against which I argue on Wikipedia talk:What is a troll is just one example of the trend to obfuscate the process of writing the encyclopaedia.

The central problem with this is that it's bad for the project. It's very frustrating to argue a bit of information that you know you are right about with a group of people who can't present coherent arguments for their POV, but are shouting or even threatening proceedings and punishment. People with unpopular views are discouraged from editing, which precludes any chances of achieving NPOV. Not just that: People with knowledge, mild manners, and an adult approach to team work are discouraged from participating in the project, which threatens to turn large Wikipedia into the encyclopaedic equivalent of a tabloid.

So, what can be done? I think that Rule by Consensus and a provision which clearly states that views of simple majority are no more valid than views of a substantial minority should be enshrined as core principles.

But the Lord of the Flies atmosphere also owes a lot to the pervasive contempt for due process - if the powers that be (admins and ArbCom by any measure) show contempt for the rules, how can they expect those they disagree with to be any better? Since people obviously care about what Wikipedia says on certain matters, this attitude inevitably invites endless edit warring and consequentially increased wikilawyering and dealing out of punishments. Mind you, a permaban on Wikipedia is the equivalent of capital punishment in the world of online lexicography.

So it would also be nice if core principles also included a provision that explicitely mandates due process - i.e. rigid adherance to the rules, once they are passed and no making up of actionable rules (i.e. those that can badly reflect on your reputation if you break them) on the spot or outside established procedure, whatever that is at the time. If issues require flexible solutions, then it's the rules that should be made flexible, not adherence to them. Zocky 21:32, 11 May 2005 (UTC)

I'm not certain that I have the right place to enter this point but it seems that "Principles" are possibly the core of everything which for example could be interpreted as a Science such as Mathematics, Logic, Physics, etc should be deriveable from (product of) its principles.

I searched Wikipedia for "Scientific Principles" and had "Scientific Method" returned. I dont even see this as close when viewed from perspective of "The Principles of Mathematics" by Bertrand Russell. So who should define Principles of Science, or Principles of anything since Lord Russell is no longer with us? shirleyjwb@hotmail.com
 * Bravo for the Zocky comments and kudos for his efforts. Today, my only thoughts are that Wikipedia simply is not pleasurable at all. Everything I do is reversed and never edited or improved but instead is eliminated with the lamest explanations. I do not come to Wikipedia for a debate contest. Wikipedia is not another form of social media. But uneducated trolls have invaded and must be weeded out somehow. Good luck. -- DHT863 (talk) 16:55, 8 February 2018 (UTC)

Mailing list(s) vs. Talk/discussion pages ?
Is #6 still or really true?

I've been finding tons of "meta" stuff & opinions in these Talk pages + Meta.Wikimedia.org without even considering the existence mailing lists (which I eventually found a link to at Help:Contents).

P.S. - I've got plenty to read already! PLEASE DON'T ADD ME TO ANY MAILING LISTS! ;-)

-- Curious1i 04:24, 28 November 2005 (UTC)

Statement of Principles
I'm not sure this is the right place to provide feedback on the statement of principles. If it isn't, please point me to the write place. Anyhow, I think no. 1, "Wikipedia's success to date is 100% a function of our open community" sounds horribly awkward. The same sentiment can be conveyed in a better-worded sentence. I propose Wikipedia's success is a function of its open community, or if we want to stress the point, Wikipedia's success is entirely a function of its open community. At the very least, I think "100%" (which reads like an informercial) should be replaced with "entirely". --Ori.livneh 00:02, 17 June 2006 (UTC)

Date of this statement
Can someone in the know note both the date and source of this statement? The earliest recorded edit is by a conversion bot. - BT 15:39, 7 August 2006 (UTC)

Date for "Statement of Principles" (again)
Ah. I see someone else (see above) has asked the same question! See also the discussion here (may soon be moved to here in Archive 11) and in here in Archive 7. The latter discussion led to a date of February 2002 from the history page for /Statement of Principles, but the more recent discussion with JesseW led to a date of 27 October 2001 as possbily the earliest date for this Statement of Principles being published on Wikipedia. Jesse kindly added this data to this subpage within the existing 'noinclude' tags so that it doesn't appear on the front page. In the spirit of Jimbo Wales's comment on his user page: "You may edit this page Really, you can! Feel free!" - and hoping that it applies to subpages, I am going to reword this bit, put a bit outside the "noinclude" tags, and leave the actual link to the nostalgia version inside the noinclude tags. I will also place a note on the main talk page to notify Jimbo so he can revert all this if he wants. Carcharoth 09:56, 3 September 2006 (UTC)

RAS Syndrome
I hope you don't mind that I changed "GNU FDL License" to "GNU Free Documentation License", removing the redundant word "license" to avoid RAS Syndrome. I expanded the acronym instead of just deleting the word, because I thought the acronym was too obscure for someone reading the principles for the first time and trying to get the high level meaning. Mditto 20:02, 18 September 2007 (UTC)

The story behind this SOP, and the exact date (!)
Let me get off my rocking chair, put away my Zimmer frame and tell you the story behind this Statement. It is far more complicated that you might think. Firstly, do not trust the History logs on Nostalgia - they are at best only 10% accurate.

It was October 2001 and I had been here for a month or two. We were doing well, we had been mentioned in the NY Times and we had just passed 15,000 articles. And the Cunctator had launched an all-out assault on Jimbo and Larry. Now the Cunctator is one of the most quixotic characters in the history of WP. He was amazingly intelligent and capable of creating exceptionally good articles. Some of his thoughts still permeate wikipedia policies today. But he was hands-down the most disruptive editor in the first two years of Wikipedia and he drove Larry Sanger to the brink of insanity by nitpicking every possible thing Larry ever said.

Anyway on around 15 October Cunc wrote How To Destroy Wikipedia, which is fairly slanderous as regards Jimbo and Larry. It was even highly critical of Magnus (who wrote the Phase II software). As a sidenote, even I was implicated as it also contains reference to "Why ManningBartlett left". For the record, this was a total distortion of the truth. I had had a minor spat with Tim Shell (can't even remember what it was about), and then had to go on a business trip to India so was offline for about two weeks. Cunc decided that I had "left the project in disgust" and accused Larry and Jimbo of being responsible for "driving good people away".

On 26 October 2001 The Cunctator decided to launch an all-out-assault on Jimbo regarding the GFDL. JImbo got VERY pissed off, and he wrote the "Statement of Principles" as a means of blowing off steam. It was published only a few hours after the GFDL page, so I would pinpoint its creation to 26 Oct 2001.

There was nothing new in the statement - it was really a summary of things Jimbo had been saying since day one. But it still stands as the foundation of the core values of WP, even to this day.

Manning (talk) 00:18, 29 November 2007 (UTC)

Right Thing
The words are tagged to link to an article within Wiki, but are highlighted in red, ie the link leads nowhere... Perhaps this ought to be corrected? Jubilee♫ clipman 18:42, 10 December 2008 (UTC)

Licensing change to CC-BY-SA
This is going to need updating come June 15. GreenReaper (talk) 07:49, 25 May 2009 (UTC)

Is this the original version, and if not, link?
Is this the original version, and if not, link?   M   00:13, 31 July 2009 (UTC)
 * The oldest version is indeed linked from the front page, but here is a link for you :) NW ( Talk ) 00:50, 31 July 2009 (UTC)

Redirected Link
The [no cabal] link currently goes to Backbone cabal. Perhaps:

 * Cabal
 * Cabals
 * Cabals_are_evil or
 * Cabal_(disambiguation)

would be better.69.142.154.10 (talk) 13:39, 24 July 2010 (UTC)

Category:Wikipedia Basic information
I've fixed the cat on this page. This page is (technically) not a policy or a guideline, and that P&G cat should normally be (almost) empty anyway, as everything should be in subcats. WhatamIdoing (talk) 22:43, 16 September 2010 (UTC)

Dear Jimbo, did you intend to create, in other editors' words, "American television watchers' encyclopedia"?
Many pages and articles seem to be in direct contradiction with your statement of principles...

Shouldn't Wikipedia strive to be a better encyclopedia?

You are invited to join the discussion at Talk:Big_Bang_Theory_(disambiguation).

70.27.12.150 (talk) 05:27, 15 March 2012 (UTC)

Homeopathy article and the parody of Neutral point of view
I always wanted to ask you how is it possible that controversial articles like homeopathy make neutral point of view looks like parody? What is wrong and how it can be corrected - I have no idea - I have no ....conflict of interest but I did and do have good intentions. For a curious editor, it would take 15 min to understand the problem. http://en.wikipedia.org/wiki/Talk:Homeopathy#Heavily_Biased_article. Best regards. — Preceding unsigned comment added by Motorola12 (talk • contribs) 00:14, 11 January 2013 (UTC)
 * My guess is that Mr. Wales does not monitor this page. Butwhatdoiknow (talk) 02:28, 12 January 2013 (UTC)

Suggestion to rephrase comment.
Rephrased for (objectionable wording?) We must not let the "squeaky wheel" be greased just for being a jerk.@ User:Jimbo Wales/Statement of principles §Priciples #7 replace with: We must not let the greasing of the "squeaky wheel" be just an ephemeral fix. — Preceding unsigned comment added by Deermouse (talk • contribs) 17:42, 28 March 2018 (UTC)