title: Lancia

text: In 1974 the badge was redesigned on Umberto Agnelli's request; it went back to a modernised silver, white and blue version of the 1929 design. Flag and lance were unified in a single shape and dispensed with the earlier minute detailing, the Lancia letters became all of the same size, and the steering wheel became also outlined in blue and lost the hand throttle detail. This logo debuted on the 1979 Lancia Delta, and made its way on the other models as they adopted the split grille introduced by the Delta. Though lightly revised in 2000 with the addition of a chrome shield surround, the 1974 logo was used through four decades, up to 2006.


title: Lancia

text: The current logo, designed by Robilant Associati, was presented at the 2007 Geneva Motor Show—a couple of months after the creation of Lancia Automobiles. While the traditional chrome-framed blue shield has been retained and made three-dimensional, for the first time since 1911 lance and flag are absent; the steering wheel has been stylized into a chromed circle, from which two spikes converge towards the modern Lancia logotype in the centre.


title: Lancia

text: Cavalier Giuseppe Lancia (1860 (Cuneo) - 1919 (Bordighera) was an Italian businessman and father of Vincenzo Lancia. When he was sixteen he started a business with food in Italy. Later, for a few years, he made relationships with South America and he created a food industry in Argentina. His efforts and innovations made his company a great success. His company was one of the first food companies in the country and showed new methods in this sector. When he made a fortune, he returned to Italy. By his education, Giuseppe was a translator. In 1875, he married Marianna Orazzi. In 1876, their first son Giovanni was born. In 1879 their daughter Margherita was born. She died in 1894. In 1881, their third child, Vincenzo Lancia, was born. Their second daughter, Anna Maria (later Anna-Maria-Giacobinni), was born in 1884. In their free time, the Lancias spent their time at a villa near Turin.


title: Lancia

text: Vincenzo Lancia was born on 24 August 1881 in Fobello near Turin. His father wanted Vincenzo to be a lawyer, but did not have much interest in the humanities. He met the Battista brothers as well as Giovanni Ceirano and became interested in science and technology, especially automobiles. He saw his first cars in Turin and Milan. One of his friends, Carlo Bishareti di Ruffia, had a Benz and that was the first important automobile in his life. When FIAT was founded in 1899, Vincenzo was very active in the company and later became one of the most famous test drivers of Italian automobile brands. In 1922, Vincenzo married his secretary - Adele Miglietti. Vincenzo and Adele had three children: Gianni, Eleonora and Maria. He died on February 15, 1937.


title: Lancia

text: Gianni Lancia was born on 24 November 1924 in Turin. He finished his education with his sisters at the Technical University of Pisa. From the time he was a little boy Gianni loved sports, but his greatest passion was motor racing. This led him to become a driver for the Lancia team. Gianni became the boss of Lancia in 1950. He invested a lot of money in expensive prototypes and other unprofitable ventures that led him to sell a big part of the company to Carlo Pesenti in 1957. After that he started a business in the food industry. For a few years he lived in Brazil. He had two sons, Mariele and Vincenzo, from his first marriage, and one son, Lorenzo Lancia, from his marriage to Jacqueline Sassard. He died on 30 June 2014.


title: Lancia

text: The Ypsilon is a premium 5-door supermini car produced since 2011. It is based on an updated Fiat 500 platform. It was previously available for sale in many European markets; however, since 2017, it has only been available in Italy. In the United Kingdom and Ireland it was previously sold as the "Chrysler Ypsilon".


title: Lancia

text: Although it is the only Lancia car in production and only for sale in Italy, the Ypsilon continues to be popular there; it was the second best-selling car in Italy in 2019.


title: Lancia

text: The Lancia Aurelia introduced the front engine rear transmission configuration later used by Ferrari, Alfa Romeo, Porsche, GM, Volvo and Maserati, as well as the V6 engine, which is now common. It had inboard rear brakes, an important way of reducing un-sprung weight.


title: Lancia

text: The Lancia Stratos was a successful rally car during the 1970s, and helped the company to improve its sporting credentials.


title: Lancia

text: The second generation Lancia Thema executive car (2011 – 2014) was a re-branded second generation Chrysler 300 unveiled in 2011 to replace the Thesis. It reused the name of the Italian made 1984–94 Thema saloon. It used to be available in various European markets, but for the United Kingdom and Ireland it was only sold as the "Chrysler 300C". It was discontinued in 2015.


title: Lancia

text: The Lancia Voyager was a large MPV unveiled in 2011, which was based on the Chrysler Town & Country. It was marketed in various European markets, but for the United Kingdom and Ireland it was only sold as the "Chrysler Grand Voyager". It was discontinued in 2015.


title: Lancia

text: Between 2012 and 2014, the Chrysler 200 Convertible was rebranded and marketed under the Lancia Flavia name. The Flavia was only available in left-hand drive markets, and thus not sold in the United Kingdom or Ireland.


title: Lancia

text: Lancia has shown several concept cars to the public including the Flaminia Loratmo (1958), Stratos Zero (1970), the Megagamma by Italdesign Giugiaro and Sibilo by Bertone in 1978, Hit (1988) by Pininfarina, the Bertone-designed Kayak (1995), the Dialogos (1998) and Nea in 2000. The company showed the Granturismo Stilnovo and Fulvia concepts in 2003.


title: Lancia

text: In the end of 1960, Lancia made their first landaulet-limousine for the President of Italy, called the Lancia Flaminia 335 Presidenziale.


title: Lancia

text: In 1999, Lancia made a one-off limousine version of the Kappa and at the 2004 Geneva Motor Show, Stola showed a limousine version of the Thesis.


title: Lancia

text: In January 2014, in an interview with "La Repubblica", Fiat CEO Sergio Marchionne foreshadowed that Lancia would become an Italy–only brand, and focus only on the Ypsilon supermini range.


title: Lancia

text: While some models had been imported on a small scale during the 1950s to the 1960s, Lancias were sold in the United States from 1975. Sales were comparatively slow, and the range was withdrawn at the same time as Fiat in 1982.


title: Lancia

text: In 2009, following Fiat's acquisition of a stake in United States-based Chrysler and part of Chrysler's restructuring plans, it was stated that Fiat plans for the Chrysler brand and Lancia to co–develop products, with some vehicles being shared. Olivier Francois, Lancia's CEO, took over as CEO of the Chrysler division in October 2009. Fiat also announced that, depending on the market, some Chrysler cars would be sold as Lancias and vice versa.


title: Lancia

text: Francois' plans to re-establish the Chrysler brand as an upscale brand were somewhat muddied by the discontinuance of the Plymouth brand. At the 2010 Detroit Auto Show, a Chrysler-badged Lancia Delta was on display, but this did not result in sales in the United States, with proposals to instead modify an Alfa Romeo for sale by 2013.


title: Lancia

text: Lancia's reputation was significantly undermined in 1980, when defective Lancia Beta models, suffering from significant suspension sub-frame corrosion problems, were purchased back from owners by the company in a highly publicised campaign. These cars were later crushed. The brand never recovered from the damage inflicted during the Beta recall and, combined with a range of related factors (including poor residual values, which made their range uncompetitive), decided to withdraw from the right-hand drive market in February 1994. The last model to be sold in the United Kingdom was the Delta, boosted by its rallying reputation, withdrawn from sale in 1995, although a small number of left-hand drive Lancia models have since reached the UK as personal imports.


title: Lancia

text: After 1995, there were continuous rumours suggesting Lancia's return to the United Kingdom. In November 2005, "What Car?" reported rumours over the alleged return, to rival "affordable" premium makes, such as Saab and Volvo. In September 2006, "What Car?" reported that Lancia were returning to the United Kingdom. The relaunch date was set for August 2008. In April 2008, "Car" reported that Lancia had postponed the relaunch. In June 2009, "Autocar" reported that the relaunch of Lancia was now “very unlikely”.


title: Lancia

text: These rumours were credible since Lancia models, by that time, shared common parts with Fiat and Alfa Romeo models that were imported, sold and maintained by an existing dealership network. The cost to reestablish the brand would therefore be minimal. In December 2008, however, Fiat cancelled relaunch plans, due to financial concerns coinciding with the global financial crisis, and the recession.


title: Lancia

text: In 2011, Lancia Ypsilon and Delta models were eventually reintroduced to the United Kingdom, but were sold under the Chrysler marque. In January 2014, the slow-selling Delta model was dropped from this line-up. In March 2015, Fiat Group announced that the Chrysler brand would be discontinued in the United Kingdom in 2017, citing a desire to focus largely on the Jeep brand instead.


title: Lancia

text: A small number of Lancia models were previously sold in Japan, such as Fulvia, Stratos and Delta. More recently, some models have been sold under the Chrysler brand, such as the Ypsilon.


title: Lancia

text: After Vincenzo Lancia's son Gianni became director of the firm, it started to take part more frequently in motorsport, eventually deciding to build a Grand Prix car. Vittorio Jano was the new designer for Lancia and his Lancia D50 was entered into the 1954 Spanish Grand Prix, where Alberto Ascari took the pole position and drove the fastest lap. In the 1955 Monaco Grand Prix Ascari crashed into the harbour after missing a chicane. One week later Ascari was killed in an accident driving a Ferrari sports car at Monza. With Ascari's death and Lancia's financial problems the company withdrew from Grand Prix racing. Altogether Lancia took two victories and ten podiums in Formula One.


title: Lancia

text: Remnants of the Lancia team were transferred to Scuderia Ferrari, where Juan Manuel Fangio won the 1956 championship with a Lancia-Ferrari car.


title: Lancia

text: Lancia has been very successful in motorsport over the years, and mostly in the arena of rallying. Prior to the forming of the World Rally Championship (WRC), Lancia took the final International Championship for Manufacturers title with the Fulvia in 1972. In the WRC, they remain the most statistically successful marque (despite having withdrawn at the end of the 1993 season), winning constructors' titles with the Stratos (1974, 1975 and 1976), the 037 (1983) and the Delta (six consecutive wins from 1987 to 1992). The Delta is also the most successful individual model designation ever to compete in rallying. All this gave Lancia a total of 11 Championships over the years and 15 European Championship from 1969 to 1992.


title: Lancia

text: Juha Kankkunen and Miki Biasion both won two drivers' titles with the Delta. Among other drivers to take several World Rally Championship wins with Lancia were Markku Alén, Didier Auriol, Sandro Munari, Bernard Darniche, Walter Röhrl, Björn Waldegård and Henri Toivonen. The history of the brand in rallying is also tainted with tragedy, with deaths of Italian driver Attilio Bettega at the 1985 Tour de Corse in a Lancia 037 and then Finnish championship favourite Toivonen in a Lancia Delta S4 at the same rally exactly a year later. These deaths would eventually lead to the end of Group B rallying.


title: Lancia

text: In 1951 Mille Miglia, Lancia Aurelia B20 GT came second overall. The car was driven by Thornley Kelham.


title: Lancia

text: In 1953, Umberto Maglioli won the Targa Florio at the wheel of the Lancia D20. The same year Lancia introduced the D24 sports racer, which was an evolution of D23 model, but rebodied as a spider by Pinin Farina. Its most significant victories were the 1953 Carrera Panamericana, the 1954 Mille Miglia and the 1954 Targa Florio.


title: Lancia

text: During Lancia's dominance of rallying, the company also expanded into sports cars in the late 1970s until the mid-1980s. It first ran the Stratos HF in Group 4, and for a brief interlude with a rare Group 5 version. The car was replaced with the successful Beta Montecarlo Turbo winning the FIA's 1980 World Championship for Makes and 1981 World Endurance Championship for Makes and the 1980 Deutsche Rennsport Meisterschaft.


title: Lancia

text: In 1982 the team moved up to Group 6 with the LC1 Spyder, followed by the Group C LC2 coupé which featured a Ferrari powerplant in 1983. The LC2 was a match for the standard-setting Porsche 956 in terms of raw speed, securing 13 pole positions over its lifetime; however, its results were hampered by poor reliability and fuel economy, and it only managed to win three European and World Endurance Championship races. The team's inability to compete against the dominant Porsche 956 and 962 sports cars led it to drop out of sportscar racing at the end of 1986 in order to concentrate on rallying, although private teams continued to enter LC2s with declining results until the early 1990s.


title: Lancia

text: Lancia produced a wide range of vans, trucks, buses and military vehicles from the beginning, forming Lancia Veicoli Industriali in 1912. Lancia slowly withdrew from the commercial sectors during the late 1960s and production of commercial vehicles ended in the early 1970s, shortly after Fiat's takeover of the company, with some models transferred to Iveco.


title: Lancia

text: In 2009, the British motoring television show "Top Gear" suggested that Lancia had more 'great' models than any other car company. The presenters went on to test the Gamma Coupé, Fulvia Coupé, Aprilia, Montecarlo, Beta Coupé, HPE, Stratos, 037, Delta Integrale Evo II and Thema 8.32. They also stated during their review that Lancia made the best-looking cars, even though they are unreliable.


title: Lancia

text: Lancia sponsored the Venice Film Festival for five years, ending in 2012, with the Lancia Thema used to transport stars to the festival. Lancia was sponsor of the ninth and eleventh World Summits of Nobel Peace Prize Laureates.


title: À la carte

text: In restaurants, à la carte (; ) is the practice of ordering individual dishes from a menu in a restaurant, as opposed to "table d'hôte", where a set menu is offered. It is an early 19th century loan from French meaning "according to the menu".


title: À la carte

text: The individual dishes to be ordered may include side dishes, or the side dishes may be offered separately, in which case, they are also considered "à la carte".


title: À la carte

text: The earliest examples of "à la carte" are from 1816 for the adjectival use ("à la carte meal", for example) and from 1821 for the adverbial use ("meals were served à la carte"). These pre-date the use of the word menu, which came into English in the 1830s.


title: Timothy Omundson

text: Timothy Michael Omundson (born July 29, 1969) is an American actor. He is notable for his supporting roles as Sean Potter on the CBS television series "Judging Amy", on the syndicated series "", Carlton Lassiter in "Psych", King Richard on the musical series "Galavant", and Cain in "Supernatural".


title: Timothy Omundson

text: Omundson was born in St. Joseph, Missouri, to a railroad worker father and teacher mother. After his family moved to Bellevue, Washington, he started studying theater at the age of twelve at the Seattle Children's Theater, and interned at various theaters during his high school years. With acting as his primary focus, he studied during the summer of his junior year in New York City at the American Academy of Dramatic Arts. For two years in a row, he was Washington State Debate Champion in Dramatic Interpretation.


title: Timothy Omundson

text: With his father, Omundson spent a month traveling in Germany and Austria when he was 13 years old, a time he views as one of the most formative months of his life. After graduating from Bellevue, Washington's Interlake High School in 1987, Omundson went to the University of Southern California where he graduated with a Bachelor of Fine Arts in Theater. He won USC's "Jack Nicholson Award" and "James and Nony Doolittle Award" for outstanding achievements in acting.


title: Timothy Omundson

text: Omundson voices the character Aric Jorgan in the MMORPG "". Aric Jorgan is the first companion for the Republic Trooper class. In 2014 Omundson had a guest role on The CW's "Supernatural" especially written for him, the role of the biblical Cain. He also played a major character in the 2006 series "Psych" where he portrayed Detective Carlton Lassiter. This also includes three television movies based on the series produced by the USA Network called "" in 2017, "" in 2020, and "" which was released in November of 2021.


title: Timothy Omundson

text: He is also notable for his supporting roles as Sean Potter on the CBS television series "Judging Amy", on the syndicated series "", and King Richard on the musical series "Galavant".


title: Timothy Omundson

text: Omundson lives in Los Angeles, California with his wife, Allison, and their two daughters born 2002 and 2004. In late April 2017 he suffered a major stroke. Among other issues, the stroke was reported to have impacted his walking ability, which he relearned. Despite his physical issues, Omundson was able to reprise his role as Carlton Lassiter with a small part in "" and more substantial roles in "" and "" while he continued his recovery. He also began a recurring role in "This Is Us" where he plays a recovered stroke survivor, Gregory.


title: David Earl (actor)

text: David Geoffrey Earl (born March 1974) is a British actor and comedian, best known for his comedy character Brian Gittins. He has featured in several projects associated with Ricky Gervais, most notably as Kevin "Kev" Twine in the comedy-drama "Derek", and in smaller roles in "Extras", "After Life" and the film "Cemetery Junction". Earl also works frequently with comic Joe Wilkinson. Together they co-wrote and starred in the sitcom "Rovers", and the comedy series "The Cockfields". They also host three podcasts called "Gossipmongers", "Chatabix" and "My New Football Club".


title: David Earl (actor)

text: Before undertaking any acting roles, Earl worked as a gardener and as a van driver, delivering building tools.


title: David Earl (actor)

text: One of Earl's earliest online videos featured him playing a character called Graham, which he sent to a friend who showed it to Ricky Gervais and Stephen Merchant. They liked the video and Gervais asked Earl to play an obsessive fan, based on the character from the video, who talks to Andy Millman in a pub in an episode of "Extras". Around this time Earl played Tony Queen in the film "The Penalty King".


title: David Earl (actor)

text: Earl went on to create a number of online videos in character as Brian Gittins and played this role in the film "Cemetery Junction". In 2012 a sitcom pilot entitled "Gittins" was broadcast on Channel 4. In the pilot Gittins works as a taxi driver: previously the character had been a cafe owner and this discrepancy is highlighted in an episode of the podcast "Flatshare Slamdown", in which Earl appears as Brian. He releases regular "Brian Gittins and Friends" podcasts.


title: David Earl (actor)

text: Another of Earl's characters is Steve "Cumbo" Cumberland, who features in a number of online videos, including a Channel 4 "Comedy Blaps" series, co-written with Brett Goldstein.


title: David Earl (actor)

text: In 2011, Earl was revealed to be the person behind the popular Twitter account of Dr Peter Thraft, a supposed sex therapist.


title: David Earl (actor)

text: A live radio show hosted on Spreaker from 2012-2017, where Brian played the role of 'the worst radio presenter in the world'. Callers would Skype in from around the world, and these included David Edwards and Charles Petrescu.


title: David Earl (actor)

text: Brian, David Edwards and Charles Petrescu have a chat with various comedians. It started in 2016, with guests including John Kearns, Lolly Adefope, and Scroobius Pip.


title: David Earl (actor)

text: In 2019 David Earl, Joe Wilkinson and Poppy Hillstead began a podcast called "Gossipmongers", a weekly podcast where listeners send in unsubstantiated rumours. At the end of each episode they choose their favourite piece of gossip from that episode. In 2020 Poppy left the podcast.


title: David Earl (actor)

text: In 2021 David Earl and Joe Wilkinson began a podcast called "Chatabix", a daily weekday podcast recorded very early in the morning.


title: David Earl (actor)

text: In 2021 David Earl and Jon Beer began a podcast called "My New Football Club". A weekly podcast about David becoming a new fan of Exeter City.


title: Phone connector (audio)

text: A phone connector, also known as phone jack, audio jack, headphone jack or jack plug, is a family of electrical connectors typically used for analog audio signals. A plug, the male connector, is inserted into the jack, the female connector.


title: Phone connector (audio)

text: The phone connector was invented for use in telephone switchboards in the 19th century and is still widely used.


title: Phone connector (audio)

text: The phone connector is cylindrical in shape, with a grooved tip to retain it. In its original audio configuration, it typically has two, three, four or, occasionally, five contacts. Three-contact versions are known as "TRS connectors", where "T" stands for "tip", "R" stands for "ring" and "S" stands for "sleeve". Ring contacts are typically the same diameter as the sleeve, the long shank. Similarly, two-, four- and five-contact versions are called "TS", "TRRS" and "TRRRS connectors" respectively. The outside diameter of the "sleeve" conductor is . The "mini" connector has a diameter of and the "sub-mini" connector has a diameter of . The "mini" connector has a length of .


title: Phone connector (audio)

text: Specific models, and connectors used in specific applications, may be termed e.g. "stereo plug", "headphone jack", "microphone jack", "aux input", etc. The 3.5 mm versions are "mini-phone", "mini-stereo", "mini jack", etc.


title: Phone connector (audio)

text: In the UK, "jack plug" and "jack socket" are the male and female phone connectors. In the US, a stationary (more fixed) electrical connector is the "jack". The terms "phone plug" and "phone jack" sometimes refer to different genders of phone connectors, but also sometimes refer to the RJ11 and older telephone plugs and corresponding jacks that connect wired telephones to wall outlets.


title: Phone connector (audio)

text: Phone plugs and jacks are different from "phono plugs" and "phono jacks" (or in the UK, "phono socket") which are RCA connectors common in consumer hi-fi and audiovisual equipment. The 3.5 mm connector is, however, sometimes—but counter to the connector manufacturers' nomenclature—referred to as "mini phono".


title: Phone connector (audio)

text: Modern phone connectors are available in three standard sizes. The original version descends from as early as 1877, when the first-ever telephone switchboard was installed at 109 Court Street in Boston in a building owned by Charles Williams, Jr.; or 1878, when an early switchboard was used for the first commercial manual telephone exchange in New Haven, Connecticut created by George W. Coy. The 1877 switchboard was last known to be located in the lobby of 185 Franklin Street, Boston.


title: Phone connector (audio)

text: In February 1884, C. E. Scribner was issued US Patent 293,198 for a "jack-knife" connector that is the origin of calling the receptacle a "jack". Scribner was issued U.S. Patents 262,701, 305,021, and 489,570 relating to an improved design that more closely resembles the modern plug. The current form of the switchboard-plug was patented prior to 1902, when Henry P. Clausen received a patent on an improved design. It is today still used on mainstream musical equipment, especially on electric guitars.


title: Phone connector (audio)

text: Western Electric was the manufacturing arm of the Bell System, and thus originated or refined most of the engineering designs, including the telephone jacks and plugs which were later adopted by other industries, including the U.S. military.


title: Phone connector (audio)

text: U.S. military versions of the Western Electric plugs were initially specified in Amendment No.1, MIL-P-642, and included:


title: Phone connector (audio)

text: The 3.5 mm or "miniature" size was originally designed in the 1950s as two-conductor connectors for earpieces on transistor radios, and remains a standard still used today. This roughly half-sized version of the original, popularized by the Sony EFM-117J radio (released in 1964), is still commonly used in portable applications. The three-conductor version became very popular with its application on the Walkman in 1979, as unlike earlier transistor radios, these devices had no speaker of their own; the usual way to listen to them was to plug in headphones. There is also an EIA standard for 0.141-inch miniature phone jacks.


title: Phone connector (audio)

text: The 2.5 mm or "sub-miniature" sizes were similarly popularized on small portable electronics. They often appeared next to a 3.5 mm microphone jack for a remote control on-off switch on early portable tape recorders; the microphone provided with such machines had the on-off switch and used a two-pronged connector with both the 3.5 and 2.5 mm plugs. They were also used for low-voltage DC power input from wall adapters. In the latter role they were soon replaced by coaxial DC power connectors. 2.5 mm phone jacks have also been used as the headset jacks on mobile telephones (see ).


title: Phone connector (audio)

text: The 3.5 mm and 2.5 mm sizes are sometimes called  in and  in respectively in the United States, though those dimensions are only approximations. All sizes are now readily available in two-conductor (unbalanced mono) and three-conductor (balanced mono or unbalanced stereo) versions.


title: Phone connector (audio)

text: Four-conductor versions of the 3.5 mm plug and jack are used for certain applications. A four-conductor version is often used in compact camcorders and portable media players, providing stereo sound and composite analog video. It is also used for a combination of stereo audio, a microphone, and controlling media playback, calls, volume and/or a virtual assistant on some laptop computers and most mobile phones, and some handheld amateur radio transceivers from Yaesu. Some headphone amplifiers have used it to connect "balanced" stereo headphones, which require two conductors per audio channel as the channels do not share a common ground.


title: Phone connector (audio)

text: By the 1940s, broadcast radio stations were using Western Electric Code No. 103 plugs and matching jacks for patching audio throughout studios. This connector was used because of its use in AT&T's Long Line circuits for distribution of audio programs over the radio networks' leased telephone lines. Because of the large amount of space these patch panels required, the industry began switching to 3-conductor plugs and jacks in the late 1940s, using the WE Type 291 plug with WE type 239 jacks. The type 291 plug was used instead of the standard type 110 switchboard plug because the location of the large bulb shape on this TRS plug would have resulted in both audio signal connections being shorted together for a brief moment while the plug is being inserted and removed. The Type 291 plug avoids this by having a shorter tip.


title: Phone connector (audio)

text: Professional audio and the telecommunication industry use a diameter plug, associated with trademarked names including Bantam, TT, Tini-Telephone, and Tini-Tel. They are not compatible with standard EIA RS-453/IEC 60603-11 1/4-inch jacks. In addition to a slightly smaller diameter, they have a slightly different geometry. The three-conductor TRS versions are capable of handling balanced line signals and are used in professional audio installations. Though unable to handle as much power, and less reliable than a jack, Bantam connectors are used for professional console and outboard patchbays in recording studio and live sound applications, where large numbers of patch points are needed in a limited space. The slightly different shape of Bantam plugs is also less likely to cause shorting as they are plugged in.


title: Phone connector (audio)

text: A two-pin version, known to the telecom industry as a "310 connector", consists of two -inch phone plugs at a centre spacing of . The socket versions of these can be used with normal phone plugs provided the plug bodies are not too large, but the plug version will only mate with two sockets at  inches centre spacing, or with line sockets, again with sufficiently small bodies. These connectors are still used today in telephone company central offices on "DSX" patch panels for DS1 circuits. A similar type of 3.5 mm connector is often used in the armrests of older aircraft, as part of the on-board in-flight entertainment system. Plugging a stereo plug into one of the two mono jacks typically results in the audio coming into only one ear. Adapters are available.


title: Phone connector (audio)

text: A short-barrelled version of the phone plug was used for 20th century high-impedance mono headphones, and in particular those used in World War II aircraft. These have become rare. It is physically possible to use a normal plug in a short socket, but a short plug will neither lock into a normal socket nor complete the tip circuit.


title: Phone connector (audio)

text: Less commonly used sizes, both diameters and lengths, are also available from some manufacturers, and are used when it is desired to restrict the availability of matching connectors, such as inside diameter jacks for fire safety communication in public buildings.


title: Phone connector (audio)

text: US military phone connectors include both 0.25-in. (6.35 mm) and 0.21-in. (5.34 mm) diameter plugs, which both mate with the M641-series open frame jacks, exemplified by Switchcraft C11 and C12 series jacks. Military specifications and standards relating to phone connectors include MIL-STD 202, MIL-P-642/*, and MIL-J-641.


title: Phone connector (audio)

text: Commercial and general aviation (GA) civil airplane headset plugs are similar, but not identical. A standard -in. monaural plug, type PL-55 (both two-conductor phone plugs, also called PJ-055B, which mate with JK-24 and JK-34A jacks) is used for headphones. On many newer GA aircraft the headphone jack is a standard -in. phone connector wired in the standard unbalanced stereo configuration instead of the PJ-055 to allow stereo music sources to be reproduced.


title: Phone connector (audio)

text: Aviation headphones are paired with special tip-ring-sleeve, 3/16-in (0.206 in)/5.23-mm diameter plug, type PJ-068 (PL-68), for the microphone. The PJ-068 mates with a JK-33 jack (Switchcraft C-12B), and is similar to the Western Electric plug WE-109. In the microphone plug the Ring is used for the microphone "hot" and the sleeve is ground. The extra (tip) connection in the microphone plug is often left unconnected but is also sometimes used for various functions, most commonly an optional push-to-talk switch, but on some aircraft it carries headphone audio and on others a DC supply.


title: Phone connector (audio)

text: Military aircraft and civil helicopters have another type termed a U-174/U; These are also known as "NATO plugs" or Nexus TP120 phone plugs. They are similar to -in. (6.35 mm) plug, but with a diameter short shaft with an extra ring, i.e. four conductors in total, allowing two for the headphones (mono), and two for the microphone. There is a confusingly similar four conductor British connector with a slightly smaller diameter and a different wiring configuration used for headsets in many UK Military aircraft and often also referred to as a NATO or "UK NATO" connector.


title: Phone connector (audio)

text: The original application for the 6.35 mm ( in) phone jack was in manual telephone exchanges. Many different configurations of these phone plugs were used, some accommodating five or more conductors, with several tip profiles. Of these many varieties, only the two-conductor version with a rounded tip profile was compatible between different manufacturers, and this was the design that was at first adopted for use with microphones, electric guitars, headphones, loudspeakers, and other audio equipment.


title: Phone connector (audio)

text: When a three-conductor version of the 6.35 mm plug was introduced for use with stereo headphones, it was given a sharper tip profile in order to make it possible to manufacture jacks that would accept only stereo plugs, to avoid short-circuiting the right channel of the amplifier. This attempt has long been abandoned, and now the convention is that all plugs fit all sockets of the same size, regardless of whether they are balanced or unbalanced, mono or stereo. Most 6.35 mm plugs, mono or stereo, now have the profile of the original stereo plug, although a few rounded mono plugs are still produced. The profiles of stereo miniature and sub-miniature plugs have always been identical to the mono plugs of the same size.


title: Phone connector (audio)

text: Because of a lack of standardization in the past regarding the dimensions (length) given to the ring conductor and the insulating portions on either side of it in 6.35 mm ( in) phone connectors and the width of the conductors in different brands and generations of sockets, there are occasional issues with compatibility between differing brands of plug and socket. This can result in a contact in the socket bridging (shorting) the ring and sleeve contacts on a phone connector.


title: Phone connector (audio)

text: In the most common arrangement, consistent with the original intention of the design, the male plug is connected to a cable, and the female socket is mounted in a piece of equipment. A considerable variety of line plugs and panel sockets is available, including plugs suiting various cable sizes, right-angle plugs, and both plugs and sockets in a variety of price ranges and with current capacities up to 15 amperes for certain heavy-duty  in versions intended for loudspeaker connections.


title: Phone connector (audio)

text: Personal computer sound cards, such as Creative Labs' Sound Blaster line, use a 3.5 mm phone connector as a mono microphone input, and deliver a 5 V bias voltage on the ring to power the FET preamplifier built into electret microphones. Adjustments may be required to achieve compatibility between different manufacturers.


title: Phone connector (audio)

text: The Apple PlainTalk microphone jack used on some older Macintosh systems is designed to accept an extended 3.5 mm three-conductor phone connector; in this case, the tip carries power for a preamplifier inside the microphone. It cannot accept a standard microphone without a preamp. If a PlainTalk-compatible microphone is not available, the jack can accept a line-level sound input.


title: Phone connector (audio)

text: Normally, 3.5 mm three-conductor sockets are used in computer sound cards for stereo output. Thus, for a sound card with 5.1 output, there will be three sockets to accommodate six channels: front left and right; surround left and right; and center and subwoofer. 6.1 and 7.1 channel sound cards from Creative Labs, however, use a single three-conductor socket (for the "front" speakers) and two four-conductor sockets. This is to accommodate rear-center (6.1) or rear left and right (7.1) channels without the need for additional sockets on the sound card.


title: Phone connector (audio)

text: Some portable computers have a combined 3.5 mm TRS-TOSLINK jack, supporting stereo audio output using a TRS connector, or TOSLINK (stereo or 5.1 Dolby Digital/DTS) digital output using a suitable optical adapter. Most iMac computers have this digital/analog combo output feature as standard, with early MacBooks having two ports, one for analog/digital audio input and other for output. Support for input was dropped on various later models


title: Phone connector (audio)

text: Some newer computers, such as Lenovo laptops, have 3.5 mm TRRS headset sockets, which are compatible with phone headsets and may be distinguished by a headset icon instead of the usual headphones or microphone icons. These are particularly used for voice over IP.


title: Phone connector (audio)

text: Equipment requiring video with stereo audio input or output sometimes uses 3.5 mm TRRS connectors. Two incompatible variants exist, of and length, and using the wrong variant may either simply not work, or could cause physical damage.


title: Phone connector (audio)

text: Attempting to fully insert the longer (17 mm) plug into a receptacle designed for the shorter (15 mm) plug may damage the receptacle, and may damage any electronics located immediately behind the receptacle. However, partially inserting the plug will work as the tip/ring/ring distances are the same for both variants.


title: Phone connector (audio)

text: A shorter plug in a socket designed for the longer connector may not be retained firmly and may result in wrong signal routing or a short circuit inside the equipment (e.g. the plug tip may cause the contacts inside the receptacle – tip/ring 1, etc. - to short together).


title: Phone connector (audio)

text: The shorter 15 mm TRRS variant is more common and physically compatible with standard 3.5 mm TRS and TS connectors.


title: Phone connector (audio)

text: Many small video cameras, laptops, recorders and other consumer devices use a 3.5 mm microphone connector for attaching a microphone to the system. These fall into three categories:


title: Phone connector (audio)

text: Three- or four-conductor (TRS or TRRS) 2.5 mm and 3.5 mm sockets are common on older cell phones and newer smartphones respectively, providing mono (three conductor) or stereo (four conductor) sound and a microphone input, together with signaling (e.g., push a button to answer a call). These are used both for handsfree headsets and for stereo headphones.


title: Phone connector (audio)

text: 3.5 mm TRRS (stereo-plus-mic) sockets became particularly common on smartphones, and have been used e.g. by Nokia since 2006; they are often compatible with standard 3.5 mm stereo headphones. Some computers now also include a TRRS headset socket, compatible with the headsets intended for smartphones.


title: Phone connector (audio)

text: The four conductors of a TRRS connector are assigned to different purposes by different manufacturers. Any 3.5 mm plug can be plugged mechanically into any socket, but many combinations are electrically incompatible. For example, plugging TRRS headphones into a TRS headset socket, TRS headset into a TRRS socket, or plugging TRRS headphones from one manufacturer into a TRRS socket from another may not function correctly, or at all. Mono audio will usually work, but stereo audio or the microphone may not work.


title: Phone connector (audio)

text: Two different forms are frequently found, both of which place left audio on the tip and right audio on the first ring (for compatibility with stereo connectors). Where they differ is in the placement of the microphone and return contacts.


title: Phone connector (audio)

text: The first, which places the ground return on the sleeve and the microphone on the second ring, is standardized in OMTP and has been accepted as a national Chinese standard YDT 1885–2009. It is mostly used on older devices, such as older Nokia mobiles, older Samsung smartphones, and some Sony Ericsson phones, and products meant for the Chinese market. Headsets using this wiring may be indicated by black plastic separators between the rings.


title: Phone connector (audio)

text: The second, which reverses these contacts, with the microphone on the sleeve, is used by Apple's iPhone line until the 6S and SE (1st), and has become the de facto TRRS standard, to maintain compatibility with these products. It is now used by HTC devices, recent Samsung, Nokia, and Sony phones, among others. This is referred to as CTIA/AHJ, and has the disadvantage that the mic will be shorted to ground if the body of the device is metal and the sleeve has a flange that contacts it. Headsets using this wiring may be indicated by white plastic separators between the rings.


title: Phone connector (audio)

text: If a CTIA headset is connected to a mobile phone with OMTP interface, the missing ground will effectively connect speakers in out-of-phase series, resulting in no voice on typical popular music recordings where the singers are in the center; in this case, if the main microphone button is held down, shorting across the microphone and restoring ground, the correct sound may be audible.


title: Phone connector (audio)

text: The 4-pole 3.5 mm connector is defined by the Japanese standard JEITA/EIAJ RC-5325A, "4-Pole miniature concentric plugs and jacks", originally published in 1993. 3-pole 3.5 mm TRS connectors are defined in JIS C 6560. See also JIS C 5401 and IEC 60130-8.


title: Phone connector (audio)

text: The "USB Type-C Cable and Connector Specification" specifies a mapping from a USB-C jack to a 4-pole TRRS jack, for the use of headsets, and supports both CTIA and OMTP (YD/T 1885–2009) modes. Some devices transparently handle many jack standards, and there are hardware implementations of this available as components. This is accomplished in some cases by applying a voltage to the sleeve and second ring to detect the wiring. The last two conductors may then be switches to allow a device made to one standard to be used with a headset made to the other.


title: Phone connector (audio)

text: A TRRRS standard for 3.5 mm connectors was developed by ITU-T. The standard, called P.382 (formerly P.MMIC), outlines technical requirements and test methods for a 5-conductor socket and plug configuration. Compared to the TRRS standard, TRRRS provides one extra conductor that can be used for connecting a second microphone or providing power to or from the audio accessory.


title: Phone connector (audio)

text: P.382 requires compliant sockets and plugs to be backward compatible with legacy TRRS and TRS connectors. Therefore, P.382-compliant TRRRS connectors should allow for seamless integration when used on new products. TRRRS connectors enable the following audio applications: active noise canceling, binaural recording and others, where dual analog microphone lines can be directly connected to a host device. It was commonly found on Sony phones starting with the Xperia Z1-XZ1 and Xperia 1 II.


title: Phone connector (audio)

text: Another TRRRS standard for 4.4 mm connectors following JEITA RC-8141C was introduced in 2015 and is used for balanced audio connections, in particular for headphone cables. This connector is often called a "Pentaconn" connector following the brand name of Nippon DICS (NDICS). It is used by some Sony products like the M1Z Walkman of their Signature series and by some Sennheiser products like the HD 820 headphone or the HDC 820 DAC headphone amplifier.


title: Phone connector (audio)

text: Panel-mounting jacks are often provided with switch contacts. Most commonly, a mono jack is provided with one normally closed (NC) contact, which is connected to the tip (live) connection when no plug is in the socket, and disconnected when a plug is inserted. Stereo sockets commonly provide two such NC contacts, one for the tip (left channel live) and one for the ring or collar (right channel live). Some designs of jack also have such a connection on the sleeve. As this contact is usually ground, it is not much use for signal switching, but could be used to indicate to electronic circuitry that the socket was in use.


title: Phone connector (audio)

text: Less commonly, some jacks are provided with normally open (NO) or change-over contacts, and/or the switch contacts may be isolated from the connector.


title: Phone connector (audio)

text: The original purpose of these contacts was for switching in telephone exchanges, for which there were many patterns. Two sets of change-over contacts, isolated from the connector contacts, were common. The more recent pattern of one NC contact for each signal path, internally attached to the connector contact, stems from their use as headphone jacks. In many amplifiers and equipment containing them, such as electronic organs, a headphone jack is provided that disconnects the loudspeakers when in use. This is done by means of these switch contacts. In other equipment, a dummy load is provided when the headphones are not connected. This is also easily provided by means of these NC contacts.


title: Phone connector (audio)

text: Other uses for these contacts have been found. One is to interrupt a signal path to enable other circuitry to be inserted. This is done by using one NC contact of a stereo jack to connect the tip and ring together when no plug is inserted. The tip is then made the output, and the ring the input (or vice versa), thus forming a patch point.


title: Phone connector (audio)

text: Another use is to provide alternative mono or stereo output facilities on some guitars and electronic organs. This is achieved by using two mono jacks, one for left channel and one for right, and wiring the NC contact on the right channel jack to the tip of the other, to connect the two connector tips together when the right channel output is not in use. This then mixes the signals so that the left channel jack doubles as a mono output.


title: Phone connector (audio)

text: Where a 3.5 mm or 2.5 mm jack is used as a DC power inlet connector, a switch contact may be used to disconnect an internal battery whenever an external power supply is connected, to prevent incorrect recharging of the battery.


title: Phone connector (audio)

text: A standard stereo jack is used on most battery-powered guitar effects pedals to eliminate the need for a separate power switch. In this configuration, the internal battery has its negative terminal wired to the sleeve contact of the jack. When the user plugs in a two-conductor (mono) guitar or microphone lead, the resulting short circuit between sleeve and ring connects an internal battery to the unit's circuitry, ensuring that it powers up or down automatically whenever a signal lead is inserted or removed. A drawback of this design is the risk of inadvertently discharging the battery if the lead is not removed after use, such as if the equipment is left plugged in overnight.


title: Phone connector (audio)

text: The connector assembly is usually made by few hollow and one solid pins. The jack is then assembled together by using an electric insulator material (such as plastics e.g. POM) into a single piece in such a way that pins don't short circuit.


title: Phone connector (audio)

text: When a phone connector is used to make a balanced connection, the two active conductors are both used for a monaural signal. The ring, used for the right channel in stereo systems, is used instead for the inverting input. This is a common use in small audio mixing desks, where space is a premium and they offer a more compact alternative to XLR connectors. Another advantage offered by TRS phone connectors used for balanced microphone inputs is that a standard unbalanced signal lead using a TS phone jack can simply be plugged into such an input. The ring (right channel) contact then makes contact with the plug body, correctly grounding the inverting input.


title: Phone connector (audio)

text: A disadvantage of using phone connectors for balanced audio connections is that the ground mates last and the socket grounds the plug tip and ring when inserting or disconnecting the plug. This causes bursts of hum, cracks and pops and may stress some outputs as they will be short circuited briefly, or longer if the plug is left half in.


title: Phone connector (audio)

text: This problem does not occur when using the 'gauge B' (BPO) phone connector (PO 316) which although it is of 0.25 in (6.35 mm) diameter has a smaller tip and a recessed ring so that the ground contact of the socket never touches the tip or ring of the plug. This type was designed for balanced audio use, being the original telephone 'switchboard' connector and is still common in broadcast, telecommunications and many professional audio applications where it is vital that permanent circuits being monitored (bridged) are not interrupted by the insertion or removal of connectors. This same tapered shape used in the 'gauge B' (BPO) plug can be seen also in aviation and military applications on various diameters of jack connector including the PJ-068 and 'bantam' plugs. The more common straight-sided profile used in domestic and commercial applications and discussed in most of this article is known as 'gauge A'.


title: Phone connector (audio)

text: Phone connectors with three conductors are also commonly used as unbalanced audio "patch points" (or "insert points", or simply "inserts"), with the output on many mixers found on the tip (left channel) and the input on the ring (right channel). This is often expressed as "tip send, ring return". Other mixers have unbalanced insert points with "ring send, tip return". One advantage of this system is that the switch contact within the panel socket, originally designed for other purposes, can be used to close the circuit when the patch point is not in use. An advantage of the "tip send" patch point is that if it is used as an output only, a 2-conductor mono phone plug correctly grounds the input. In the same fashion, use of a "tip return" insert style allows a mono phone plug to bring an unbalanced signal directly into the circuit, though in this case the output must be robust enough to withstand being grounded. Combining "send" and "return" functions via single  in TRS connectors in this way is seen in very many professional and semi-professional audio mixing desks, because it halves the space needed for insert jack fields which would otherwise need two jacks, one for "send" and one for "return". The tradeoff is that unbalanced signals are more prone to buzz, hum and outside interference.


title: Phone connector (audio)

text: In some three-conductor TRS phone inserts, the concept is extended by using specially designed phone jacks that will accept a mono phone plug partly inserted "to the first click" and will then connect the tip to the signal path without breaking it. Most standard phone connectors can also be used in this way with varying success, but neither the switch contact nor the tip contact can be relied upon unless the internal contacts have been designed with extra strength for holding the plug tip in place. Even with stronger contacts, an accidental mechanical movement of the inserted plug can interrupt signal within the circuit. For maximum reliability, any usage involving "first click" or "half-click" positions will instead rewire the plug to short tip and ring together and then insert this modified plug all the way into the jack.


title: Phone connector (audio)

text: The TRS "tip return, ring send" unbalanced insert configuration is mostly found on older mixers. This allowed for the insert jack to serve as a standard-wired mono line input that would bypass the mic preamp. However tip send has become the generally accepted standard for mixer inserts since the early-to-mid 1990s. The TRS "ring send" configuration is still found on some compressor sidechain input jacks such as the dbx 166XL.


title: Phone connector (audio)

text: Some sound recording devices use a three-conductor phone connector as a mono microphone input, using the tip as the signal path and the ring to connect a standby switch on the microphone.


title: Phone connector (audio)

text: Connectors that are tarnished, or that were not manufactured within tight tolerances, are prone to cause poor connections. Depending upon the surface material of the connectors, tarnished ones can be cleaned with a burnishing agent (for solid brass contacts typical) or contact cleaner (for plated contacts).


title: Inverse-square law

text: In science, an inverse-square law is any scientific law stating that a specified physical quantity is inversely proportional to the square of the distance from the source of that physical quantity. The fundamental cause for this can be understood as geometric dilution corresponding to point-source radiation into three-dimensional space.


title: Inverse-square law

text: Radar energy expands during both the signal transmission and the reflected return, so the inverse square for both paths means that the radar will receive energy according to the inverse fourth power of the range.


title: Inverse-square law

text: To prevent dilution of energy while propagating a signal, certain methods can be used such as a waveguide, which acts like a canal does for water, or how a gun barrel restricts hot gas expansion to one dimension in order to prevent loss of energy transfer to a bullet.


title: Inverse-square law

text: In mathematical notation the inverse square law can be expressed as an intensity (I) varying as a function of distance (d) from some centre. The intensity is proportional (see ∝) to the multiplicative inverse of the square of the distance thus:


title: Inverse-square law

text: The divergence of a vector field which is the resultant of radial inverse-square law fields with respect to one or more sources is proportional to the strength of the local sources, and hence zero outside sources. Newton's law of universal gravitation follows an inverse-square law, as do the effects of electric, light, sound, and radiation phenomena.


title: Inverse-square law

text: The inverse-square law generally applies when some force, energy, or other conserved quantity is evenly radiated outward from a point source in three-dimensional space. Since the surface area of a sphere (which is 4π"r") is proportional to the square of the radius, as the emitted radiation gets farther from the source, it is spread out over an area that is increasing in proportion to the square of the distance from the source. Hence, the intensity of radiation passing through any unit area (directly facing the point source) is inversely proportional to the square of the distance from the point source. Gauss's law for gravity is similarly applicable, and can be used with any physical quantity that acts in accordance with the inverse-square relationship.


title: Inverse-square law

text: If the distribution of matter in each body is spherically symmetric, then the objects can be treated as point masses without approximation, as shown in the shell theorem. Otherwise, if we want to calculate the attraction between massive bodies, we need to add all the point-point attraction forces vectorially and the net attraction might not be exact inverse square. However, if the separation between the massive bodies is much larger compared to their sizes, then to a good approximation, it is reasonable to treat the masses as a point mass located at the object's center of mass while calculating the gravitational force.


title: Inverse-square law

text: As the law of gravitation, this law was suggested in 1645 by Ismael Bullialdus. But Bullialdus did not accept Kepler's second and third laws, nor did he appreciate Christiaan Huygens's solution for circular motion (motion in a straight line pulled aside by the central force). Indeed, Bullialdus maintained the sun's force was attractive at aphelion and repulsive at perihelion. Robert Hooke and Giovanni Alfonso Borelli both expounded gravitation in 1666 as an attractive force. Hooke's lecture "On gravity" was at the Royal Society, in London, on 21 March. Borelli's "Theory of the Planets" was published later in 1666. Hooke's 1670 Gresham lecture explained that gravitation applied to "all celestiall bodys" and added the principles that the gravitating power decreases with distance and that in the absence of any such power bodies move in straight lines. By 1679, Hooke thought gravitation had inverse square dependence and communicated this in a letter to Isaac Newton:


title: Inverse-square law

text: "my supposition is that the attraction always is in duplicate proportion to the distance from the center reciprocall".


title: Inverse-square law

text: Hooke remained bitter about Newton claiming the invention of this principle, even though Newton's 1686 "Principia" acknowledged that Hooke, along with Wren and Halley, had separately appreciated the inverse square law in the solar system, as well as giving some credit to Bullialdus.


title: Inverse-square law

text: The force of attraction or repulsion between two electrically charged particles, in addition to being directly proportional to the product of the electric charges, is inversely proportional to the square of the distance between them; this is known as Coulomb's law. The deviation of the exponent from 2 is less than one part in 10.


title: Inverse-square law

text: The intensity (or illuminance or irradiance) of light or other linear waves radiating from a point source (energy per unit of area perpendicular to the source) is inversely proportional to the square of the distance from the source, so an object (of the same size) twice as far away receives only one-quarter the energy (in the same time period).


title: Inverse-square law

text: More generally, the irradiance, "i.e.," the intensity (or power per unit area in the direction of propagation), of a spherical wavefront varies inversely with the square of the distance from the source (assuming there are no losses caused by absorption or scattering).


title: Inverse-square law

text: For example, the intensity of radiation from the Sun is 9126 watts per square meter at the distance of Mercury (0.387 AU); but only 1367 watts per square meter at the distance of Earth (1 AU)—an approximate threefold increase in distance results in an approximate ninefold decrease in intensity of radiation.


title: Inverse-square law

text: For non-isotropic radiators such as parabolic antennas, headlights, and lasers, the effective origin is located far behind the beam aperture. If you are close to the origin, you don't have to go far to double the radius, so the signal drops quickly. When you are far from the origin and still have a strong signal, like with a laser, you have to travel very far to double the radius and reduce the signal. This means you have a stronger signal or have antenna gain in the direction of the narrow beam relative to a wide beam in all directions of an isotropic antenna.


title: Inverse-square law

text: In photography and stage lighting, the inverse-square law is used to determine the “fall off” or the difference in illumination on a subject as it moves closer to or further from the light source. For quick approximations, it is enough to remember that doubling the distance reduces illumination to one quarter; or similarly, to halve the illumination increase the distance by a factor of 1.4 (the square root of 2), and to double illumination, reduce the distance to 0.7 (square root of 1/2). When the illuminant is not a point source, the inverse square rule is often still a useful approximation; when the size of the light source is less than one-fifth of the distance to the subject, the calculation error is less than 1%.


title: Inverse-square law

text: The fractional reduction in electromagnetic fluence (Φ) for indirectly ionizing radiation with increasing distance from a point source can be calculated using the inverse-square law. Since emissions from a point source have radial directions, they intercept at a perpendicular incidence. The area of such a shell is 4π"r" where "r" is the radial distance from the center. The law is particularly important in diagnostic radiography and radiotherapy treatment planning, though this proportionality does not hold in practical situations unless source dimensions are much smaller than the distance. As stated in Fourier theory of heat “as the point source is magnification by distances, its radiation is dilute proportional to the sin of the angle, of the increasing circumference arc from the point of origin”.


title: Inverse-square law

text: Let "P"  be the total power radiated from a point source (for example, an omnidirectional isotropic radiator). At large distances from the source (compared to the size of the source), this power is distributed over larger and larger spherical surfaces as the distance from the source increases. Since the surface area of a sphere of radius "r" is "A" = 4"πr", the intensity "I" (power per unit area) of radiation at distance "r" is


title: Inverse-square law

text: The energy or intensity decreases (divided by 4) as the distance "r" is doubled; if measured in dB would decrease by 6.02 dB per doubling of distance. When referring to measurements of power quantities, a ratio can be expressed as a level in decibels by evaluating ten times the base-10 logarithm of the ratio of the measured quantity to the reference value.


title: Inverse-square law

text: In acoustics, the sound pressure of a spherical wavefront radiating from a point source decreases by 50% as the distance "r" is doubled; measured in dB, the decrease is still 6.02 dB, since dB represents an intensity ratio. The pressure ratio (as opposed to power ratio) is not inverse-square, but is inverse-proportional (inverse distance law):


title: Inverse-square law

text: The same is true for the component of particle velocity formula_7 that is in-phase with the instantaneous sound pressure formula_8:


title: Inverse-square law

text: In the near field is a quadrature component of the particle velocity that is 90° out of phase with the sound pressure and does not contribute to the time-averaged energy or the intensity of the sound. The sound intensity is the product of the RMS sound pressure and the "in-phase" component of the RMS particle velocity, both of which are inverse-proportional. Accordingly, the intensity follows an inverse-square behaviour:


title: Inverse-square law

text: For an irrotational vector field in three-dimensional space, the inverse-square law corresponds to the property that the divergence is zero outside the source. This can be generalized to higher dimensions. Generally, for an irrotational vector field in "n"-dimensional Euclidean space, the intensity "I" of the vector field falls off with the distance "r" following the inverse ("n" − 1) power law


title: Inverse-square law

text: John Dumbleton of the 14th-century Oxford Calculators, was one of the first to express functional relationships in graphical form. He gave a proof of the mean speed theorem stating that "the latitude of a uniformly difform movement corresponds to the degree of the midpoint" and used this method to study the quantitative decrease in intensity of illumination in his "Summa logicæ et philosophiæ naturalis" (ca. 1349), stating that it was not linearly proportional to the distance, but was unable to expose the Inverse-square law.


title: Inverse-square law

text: In proposition 9 of Book 1 in his book "Ad Vitellionem paralipomena, quibus astronomiae pars optica traditur" (1604), the astronomer Johannes Kepler argued that the spreading of light from a point source obeys an inverse square law:


title: Inverse-square law

text: In 1645, in his book "Astronomia Philolaica" ..., the French astronomer Ismaël Bullialdus (1605–1694) refuted Johannes Kepler's suggestion that "gravity" weakens as the inverse of the distance; instead, Bullialdus argued, "gravity" weakens as the inverse square of the distance:


title: Inverse-square law

text: In England, the Anglican bishop Seth Ward (1617–1689) publicized the ideas of Bullialdus in his critique "In Ismaelis Bullialdi astronomiae philolaicae fundamenta inquisitio brevis" (1653) and publicized the planetary astronomy of Kepler in his book "Astronomia geometrica" (1656).


title: Inverse-square law

text: In 1663–1664, the English scientist Robert Hooke was writing his book "Micrographia" (1666) in which he discussed, among other things, the relation between the height of the atmosphere and the barometric pressure at the surface. Since the atmosphere surrounds the earth, which itself is a sphere, the volume of atmosphere bearing on any unit area of the earth's surface is a truncated cone (which extends from the earth's center to the vacuum of space; obviously only the section of the cone from the earth's surface to space bears on the earth's surface). Although the volume of a cone is proportional to the cube of its height, Hooke argued that the air's pressure at the earth's surface is instead proportional to the height of the atmosphere because gravity diminishes with altitude. Although Hooke did not explicitly state so, the relation that he proposed would be true only if gravity decreases as the inverse square of the distance from the earth's center.


title: Sophie Monk

text: Sophie Charlene Akland Monk (born 14 December 1979) is an Australian singer, actress, model, and television personality. She was a member of the pop girl group Bardot, winners of the first season of "Popstars Australia" in 2000, and later released a solo album titled "Calendar Girl" (2003). She has appeared in films, including "Date Movie" (2006), "Click" (2006), "Sex and Death 101" (2007), "The Hills Run Red" (2009), and "Spring Breakdown" (2009).


title: Sophie Monk

text: Monk was the winner of the fourth season of "The Celebrity Apprentice Australia" in 2015, and in 2016, she was a judge on "Australia's Got Talent". In 2017, she starred on the third season of "The Bachelorette Australia", and the following year, she became the host of "Love Island Australia". In 2021, Monk began hosting "Beauty and the Geek Australia".


title: Sophie Monk

text: Sophie Monk was born in London, England to an English father and an Australian mother. In 1982 her parents moved to Australia's Gold Coast in Queensland when she was two years old. She attended Helensvale Primary School, St Hilda's, Somerset College, A. B. Paterson College and MacGregor State High School, where she graduated as school captain in 1997. She was trained in classical opera growing up. Following graduation, Monk worked as a Marilyn Monroe impersonator at Warner Bros. Movie World on the Gold Coast.


title: Sophie Monk

text: Monk's professional music career began in 1999 when she responded to an advertisement at the recommendation of her mother which requested girls with vocal and dance experience. The advertisement was for an Australian reality television series, "Popstars", a TV talent show which aimed to create a successful new girl group. In one audition, she performed a rendition of Marilyn Monroe's famous "Happy Birthday, Mr. President", working on her previous experience as a Monroe impersonator. After numerous rounds of singing and dancing workshops, Monk was selected as a member of the group, which was named Bardot.


title: Sophie Monk

text: Bardot became the first Australian act to debut at the No. 1 position with both its debut single, "Poison", and self-titled debut album. Further singles "I Should've Never Let You Go" and "These Days" followed and in August, the group embarked on its first national tour. Bardot performed at the 2000 ARIA Awards at which they were nominated in three categories. In July 2001, the group released "ASAP", the first single from their second album. Bardot now had more control over their music and image. The single peaked Top 5, as did follow-up single, "I Need Somebody", their most successful single since "Poison". The second album, "Play It Like That" debuted at No. 16, achieving gold status. Monk co-wrote the album track "Feel Right" with bandmate Sally Polihronas. In 2002, final single, "Love Will Find A Way" completed Bardot's string of consecutive Top 20 hits and the group embarked on its second national tour. In May, the group disbanded.


title: Sophie Monk

text: In 2002, Monk signed a recording contract with Warner Music Australia and started working on a solo album. The first single "Inside Outside" was released in October 2002 and was produced by Grammy Award winning music producer Rob Davis. Monk performed the song at the 2002 "The Footy Show" Grand Finale to promote the single. The track peaked at No. 5 on the ARIA Singles Chart and went on to sell over 35,000 copies worldwide. Her next single, "Get the Music On", peaked at No. 10 on the ARIA Singles Chart. On 5 May 2003 Monk released her debut album "Calendar Girl" which peaked at No. 35 on the ARIA Albums Chart. The album received mixed reviews from critics with Monk co-writing four of the album's tracks. Following the release of the album Monk released her third and final single, "One Breath Away", which peaked at No. 23 on the ARIA Singles Chart. In 2004, Monk parted ways with Warner Music Group.


title: Sophie Monk

text: In April 2017, Monk performed with country singer Kasey Chambers at Byron Bay Bluesfest. She has expressed interest in releasing country music in the future.


title: Sophie Monk

text: In 2004, Monk made her acting debut in a bit role on the Nine Network made-for-television film "The Mystery of Natalie Wood" portraying the role of Marilyn Monroe. That same year, Monk appeared in the music video "Always" by Pop Punk band Blink-182. Monk has had small roles in films such as "Click", "Murder World" and "Spring Break '83".


title: Sophie Monk

text: In 2005, Monk relocated to Los Angeles, California to pursue a career in acting. Monk quickly landed her break-out role in the spoof comedy film "Date Movie". In July 2007, Monk made her American television debut in the HBO Comedy series "Entourage". That same year she appeared in the dark comedy "Sex and Death 101".


title: Sophie Monk

text: Monk starred in the Warner Premiere comedy film "Spring Breakdown" alongside Parker Posey and Amy Poehler. Filming took place in South Padre in 2006. Monk portrayed the role of the film's antagonist a bimbo sorority girl named Mason. The film underwent a long post-production period suffering distribution problems. The film premiered at the Sundance Film Festival to negative reviews. The film was released straight-to-DVD in June 2009.


title: Sophie Monk

text: In September 2008, Dark Castle Entertainment announced Monk was cast in the slasher horror film "The Hills Run Red". Filming began at the start of 2009 in Sofia, Bulgaria and premiered at UK Frightfest. The film was released straight-to-DVD in September 2009 to mixed reviews from critics with some praising Monk's performance. In September 2008, Monk announced she was developing her own reality television series titled "Bigger Than Paris". Monk filmed the pilot in January 2010 in Los Angeles, California.


title: Sophie Monk

text: In April 2013, Monk was working on a sitcom with actor Sam Worthington. Monk talked about her struggles as an actress and revealed that she has produced five television pilots for major networks, but they haven't been picked up. "Shows that were meant to get the green light, didn't, and movies that were meant to be massive, weren't, but I just keep going and going," she said. In 2015, Monk was added to the cast for the remake movie of "Blood Feast".


title: Sophie Monk

text: In April 2010, Nine Network announced Monk would be a special guest presenter on the travel television program "Getaway". Following her first appearance, Nine announced Monk would continue appearing on the series in a recurring form from then on. As part of her role, she has visited Hawaii, Las Vegas, Mexico.


title: Sophie Monk

text: In May 2012, Monk was announced to be one of the celebrities to have signed up for the FOX dating-show "The Choice". The series is a spin-off to "The Voice" and sees celebrity judges sitting with their backs turned to a pool of "sexy singles" hoping to score a date with a celebrity. The series premiered on 7 June 2012.


title: Sophie Monk

text: On 28 October 2015, it was confirmed that Monk would be a new judge on "Australia's Got Talent" replacing Geri Halliwell for its eighth season alongside Kelly Osbourne, Eddie Perfect and Ian "Dicko" Dickson.


title: Sophie Monk

text: In April 2017, it was announced that Monk would star on "The Bachelorette Australia". In December, she was announced as the host of "Love Island Australia", which aired on 27 May 2018 on 9Go!.


title: Sophie Monk

text: In 2020, Monk was revealed to be a participant on the second season of "The Masked Singer Australia", performing as the "Dragonfly". She was the fifth contestant eliminated, placing 8th overall.


title: Sophie Monk

text: On 16 September 2020, Monk was announced as the new host for the revival of "Beauty and the Geek Australia" on Nine Network in 2021.


title: Sophie Monk

text: In December 2021, Monk was announced as one of the four celebrity contestants for the Lego Masters Bricksmas Special alongside journalist Brooke Boney, radio and TV presenter Wippa and television presenter Scott Cam. She was partnered up with season one winner Henry.


title: Sophie Monk

text: In December 2013, Monk along with Jules Lund, Merrick Watts and Mel B were announced as the new hosts of the 2Day FM breakfast show replacing "Kyle and Jackie O Show".


title: Sophie Monk

text: In October 2014, Southern Cross Austereo announced that Jules, Merrick & Sophie on 2Day FM would be axed due to poor ratings throughout the year and replaced by "The Dan & Maz Show".


title: Sophie Monk

text: Since then, Monk has been a regular fixture on KIIS 1065's "Kyle and Jackie O Show" and has hosted "The Summer Fling" breakfast show with Matty Acton on KIIS 1065 and KIIS 101.1.


title: Sophie Monk

text: Monk has appeared in several commercials for Diet Vanilla Coke, Pepsi Max, LG Electronics, Coca-Cola and Expozay Swimwear. In 2012, she appeared in a billboard campaign for Angel Champagne on the famous La Cienega Boulevard in Hollywood.


title: Sophie Monk

text: In 2019, Monk became the brand ambassador for Australian health snack brand Slim Secrets and cosmetic brand MCO Beauty.


title: Sophie Monk

text: Monk is often spotlighted for her looks. In October 2012, Monk was ranked number 7 on Maxim Australia's Hot 100. She ranked at No. 96 in the Maxim Hot 100 List of 2011. She was No. 2 in "FHM" Sexiest Women List in 2003.


title: Sophie Monk

text: Monk is also well known for her modelling career and has appeared on the cover of several men's magazines, including "Maxim", "FHM", "Stuff" and "Ralph". In August 2008 and again in 2011, she was offered $1 million to pose for "Playboy" magazine, which she declined. Monk commented about the offer, "When I was younger I was like, 'I want to be on "Playboy".' My mum was a Playmate, she was hot." In 2014 she accepted an offer to be photographed for "Playboy". The photos were posted exclusively for viewing on the magazine's website, "Playboy Plus". Commenting about her pictorial Monk said, "Marilyn Monroe did "Playboy". It's an iconic brand, and let's get real... You only live once and I don't plan on dieting forever... I miss pizza too much!"


title: Sophie Monk

text: In January 2011, Monk announced her engagement to Jimmy Esebag. A few months later Monk announced on "Chelsea Lately" that she had separated from Esebag.


title: Sophie Monk

text: In 2013, Monk revealed she has had a stalker who wanted to kill her. "He thought he could hear me screaming in the corner of his hospital room and thought I wanted to die. So I wrote to him and told him I was fine," she said.


title: Sophie Monk

text: In October 2017, after completion of "The Bachelorette Australia," Monk began a steady relationship with the winner, Stu Laundy. In January 2018, she broke off the relationship by announcing it on Instagram.


title: Sophie Monk

text: In 2022, Sophie Monk married Joshua Gross in a secret ceremony at their New South Wales home after being in a relationship since 2018.


title: Carbon cycle

text: The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth. Carbon is the main component of biological compounds as well as a major component of many minerals such as limestone. Along with the nitrogen cycle and the water cycle, the carbon cycle comprises a sequence of events that are key to make Earth capable of sustaining life. It describes the movement of carbon as it is recycled and reused throughout the biosphere, as well as long-term processes of carbon sequestration to and release from carbon sinks. Carbon sinks in the land and the ocean each currently take up about one-quarter of anthropogenic carbon emissions each year.


title: Carbon cycle

text: Humans have disturbed the biological carbon cycle for many centuries by modifying land use, and moreover with the recent industrial-scale mining of fossil carbon (coal, petroleum and gas extraction, and cement manufacture) from the geosphere. Carbon dioxide in the atmosphere had increased nearly 52% over pre-industrial levels by 2020, forcing greater atmospheric and Earth surface heating by the Sun. The increased carbon dioxide has also increased the acidity of the ocean surface by about 30% due to dissolved carbon dioxide, carbonic acid and other compounds, and is fundamentally altering marine chemistry. The majority of fossil carbon has been extracted over just the past half century, and rates continue to rise rapidly, contributing to human-caused climate change. The largest consequences to the carbon cycle, and to the biosphere which critically enables human civilization, are still set to unfold due to the vast yet limited inertia of the Earth system. Restoring balance to this natural system is an international priority, described in both the Paris Climate Agreement and Sustainable Development Goal 13.


title: Carbon cycle

text: The carbon cycle was first described by Antoine Lavoisier and Joseph Priestley, and popularised by Humphry Davy. The global carbon cycle is now usually divided into the following major reservoirs of carbon interconnected by pathways of exchange:


title: Carbon cycle

text: The carbon exchanges between reservoirs occur as the result of various chemical, physical, geological, and biological processes. The ocean contains the largest active pool of carbon near the surface of the Earth.


title: Carbon cycle

text: The natural flows of carbon between the atmosphere, ocean, terrestrial ecosystems, and sediments are fairly balanced; so carbon levels would be roughly stable without human influence.


title: Carbon cycle

text: Carbon in the Earth's atmosphere exists in two main forms: carbon dioxide and methane. Both of these gases absorb and retain heat in the atmosphere and are partially responsible for the greenhouse effect. Methane produces a larger greenhouse effect per volume as compared to carbon dioxide, but it exists in much lower concentrations and is more short-lived than carbon dioxide, making carbon dioxide the more important greenhouse gas of the two.


title: Carbon cycle

text: Carbon dioxide is removed from the atmosphere primarily through photosynthesis and enters the terrestrial and oceanic biospheres. Carbon dioxide also dissolves directly from the atmosphere into bodies of water (ocean, lakes, etc.), as well as dissolving in precipitation as raindrops fall through the atmosphere. When dissolved in water, carbon dioxide reacts with water molecules and forms carbonic acid, which contributes to ocean acidity. It can then be absorbed by rocks through weathering. It also can acidify other surfaces it touches or be washed into the ocean.


title: Carbon cycle

text: Human activities over the past two centuries have increased the amount of carbon in the atmosphere by nearly 50% as of year 2020, mainly in the form of carbon dioxide, both by modifying ecosystems' ability to extract carbon dioxide from the atmosphere and by emitting it directly, e.g., by burning fossil fuels and manufacturing concrete.


title: Carbon cycle

text: In the far future (2 to 3 billion years), the rate at which carbon dioxide is absorbed into the soil via the carbonate–silicate cycle will likely increase due to expected changes in the sun as it ages. The expected increased luminosity of the Sun will likely speed up the rate of surface weathering. This will eventually cause most of the carbon dioxide in the atmosphere to be squelched into the Earth's crust as carbonate. Once the concentration of carbon dioxide in the atmosphere falls below approximately 50 parts per million (tolerances vary among species), C photosynthesis will no longer be possible. This has been predicted to occur 600 million years from the present, though models vary.


title: Carbon cycle

text: Once the oceans on the Earth evaporate in about 1.1 billion years from now, plate tectonics will very likely stop due to the lack of water to lubricate them. The lack of volcanoes pumping out carbon dioxide will cause the carbon cycle to end between 1 billion and 2 billion years into the future.


title: Carbon cycle

text: The terrestrial biosphere includes the organic carbon in all land-living organisms, both alive and dead, as well as carbon stored in soils. About 500 gigatons of carbon are stored above ground in plants and other living organisms, while soil holds approximately 1,500 gigatons of carbon. Most carbon in the terrestrial biosphere is organic carbon, while about a third of soil carbon is stored in inorganic forms, such as calcium carbonate. Organic carbon is a major component of all organisms living on earth. Autotrophs extract it from the air in the form of carbon dioxide, converting it into organic carbon, while heterotrophs receive carbon by consuming other organisms.


title: Carbon cycle

text: Because carbon uptake in the terrestrial biosphere is dependent on biotic factors, it follows a diurnal and seasonal cycle. In CO measurements, this feature is apparent in the Keeling curve. It is strongest in the northern hemisphere because this hemisphere has more land mass than the southern hemisphere and thus more room for ecosystems to absorb and emit carbon.


title: Carbon cycle

text: Carbon leaves the terrestrial biosphere in several ways and on different time scales. The combustion or respiration of organic carbon releases it rapidly into the atmosphere. It can also be exported into the ocean through rivers or remain sequestered in soils in the form of inert carbon. Carbon stored in soil can remain there for up to thousands of years before being washed into rivers by erosion or released into the atmosphere through soil respiration. Between 1989 and 2008 soil respiration increased by about 0.1% per year. In 2008, the global total of CO released by soil respiration was roughly 98 billion tonnes, about 3 times more carbon than humans are now putting into the atmosphere each year by burning fossil fuel (this does not represent a net transfer of carbon from soil to atmosphere, as the respiration is largely offset by inputs to soil carbon). There are a few plausible explanations for this trend, but the most likely explanation is that increasing temperatures have increased rates of decomposition of soil organic matter, which has increased the flow of CO. The length of carbon sequestering in soil is dependent on local climatic conditions and thus changes in the course of climate change.


title: Carbon cycle

text: The ocean can be conceptually divided into a surface layer within which water makes frequent (daily to annual) contact with the atmosphere, and a deep layer below the typical mixed layer depth of a few hundred meters or less, within which the time between consecutive contacts may be centuries. The dissolved inorganic carbon (DIC) in the surface layer is exchanged rapidly with the atmosphere, maintaining equilibrium. Partly because its concentration of DIC is about 15% higher but mainly due to its larger volume, the deep ocean contains far more carbon—it is the largest pool of actively cycled carbon in the world, containing 50 times more than the atmosphere—but the timescale to reach equilibrium with the atmosphere is hundreds of years: the exchange of carbon between the two layers, driven by thermohaline circulation, is slow.


title: Carbon cycle

text: Carbon enters the ocean mainly through the dissolution of atmospheric carbon dioxide, a small fraction of which is converted into carbonate. It can also enter the ocean through rivers as dissolved organic carbon. It is converted by organisms into organic carbon through photosynthesis and can either be exchanged throughout the food chain or precipitated into the oceans' deeper, more carbon-rich layers as dead soft tissue or in shells as calcium carbonate. It circulates in this layer for long periods of time before either being deposited as sediment or, eventually, returned to the surface waters through thermohaline circulation. Oceans are basic (~pH 8.2), hence CO acidification shifts the pH of the ocean towards neutral.


title: Carbon cycle

text: Oceanic absorption of CO is one of the most important forms of carbon sequestering which limit the human-caused rise of carbon dioxide in the atmosphere. However, this process is limited by a number of factors. CO absorption makes water more acidic, which affects ocean biosystems. The projected rate of increasing oceanic acidity could slow the biological precipitation of calcium carbonates, thus decreasing the ocean's capacity to absorb CO.


title: Carbon cycle

text: The geologic component of the carbon cycle operates slowly in comparison to the other parts of the global carbon cycle. It is one of the most important determinants of the amount of carbon in the atmosphere, and thus of global temperatures.


title: Carbon cycle

text: Most of the earth's carbon is stored inertly in the earth's lithosphere. Much of the carbon stored in the earth's mantle was stored there when the earth formed. Some of it was deposited in the form of organic carbon from the biosphere. Of the carbon stored in the geosphere, about 80% is limestone and its derivatives, which form from the sedimentation of calcium carbonate stored in the shells of marine organisms. The remaining 20% is stored as kerogens formed through the sedimentation and burial of terrestrial organisms under high heat and pressure. Organic carbon stored in the geosphere can remain there for millions of years.


title: Carbon cycle

text: Carbon can leave the geosphere in several ways. Carbon dioxide is released during the metamorphism of carbonate rocks when they are subducted into the earth's mantle. This carbon dioxide can be released into the atmosphere and ocean through volcanoes and hotspots. It can also be removed by humans through the direct extraction of kerogens in the form of fossil fuels. After extraction, fossil fuels are burned to release energy and emit the carbon they store into the atmosphere.


title: Carbon cycle

text: The marine biological pump is the ocean's biologically driven sequestration of carbon from the atmosphere and land runoff to the deep ocean interior and seafloor sediments. The biological pump is not so much the result of a single process, but rather the sum of a number of processes each of which can influence biological pumping. The pump transfers about 11 billion tonnes of carbon every year into the ocean's interior. An ocean without the biological pump would result in atmospheric CO levels about 400 ppm higher than the present day.


title: Carbon cycle

text: Most carbon incorporated in organic and inorganic biological matter is formed at the sea surface where it can then start sinking to the ocean floor. The deep ocean gets most of its nutrients from the higher water column when they sink down in the form of marine snow. This is made up of dead or dying animals and microbes, fecal matter, sand and other inorganic material.


title: Carbon cycle

text: The biological pump is responsible for transforming dissolved inorganic carbon (DIC) into organic biomass and pumping it in particulate or dissolved form into the deep ocean. Inorganic nutrients and carbon dioxide are fixed during photosynthesis by phytoplankton, which both release dissolved organic matter (DOM) and are consumed by herbivorous zooplankton. Larger zooplankton - such as copepods, egest fecal pellets - which can be reingested, and sink or collect with other organic detritus into larger, more-rapidly-sinking aggregates. DOM is partially consumed by bacteria and respired; the remaining refractory DOM is advected and mixed into the deep sea. DOM and aggregates exported into the deep water are consumed and respired, thus returning organic carbon into the enormous deep ocean reservoir of DIC.


title: Carbon cycle

text: A single phytoplankton cell has a sinking rate around one metre per day. Given that the average depth of the ocean is about four kilometres, it can take over ten years for these cells to reach the ocean floor. However, through processes such as coagulation and expulsion in predator fecal pellets, these cells form aggregates. These aggregates have sinking rates orders of magnitude greater than individual cells and complete their journey to the deep in a matter of days.


title: Carbon cycle

text: About 1% of the particles leaving the surface ocean reach the seabed and are consumed, respired, or buried in the sediments. The net effect of these processes is to remove carbon in organic form from the surface and return it to DIC at greater depths, maintaining a surface-to-deep ocean gradient of DIC. Thermohaline circulation returns deep-ocean DIC to the atmosphere on millennial timescales. The carbon buried in the sediments can be subducted into the earth's mantle and stored for millions of years as part of the slow carbon cycle (see next section).


title: Carbon cycle

text: There is a fast and a slow carbon cycle. The fast cycle operates in the biosphere and the slow cycle operates in rocks. The fast or biological cycle can complete within years, moving carbon from atmosphere to biosphere, then back to the atmosphere. The slow or geological cycle can take millions of years to complete, moving carbon through the Earth's crust between rocks, soil, ocean and atmosphere.


title: Carbon cycle

text: The fast carbon cycle involves relatively short-term biogeochemical processes between the environment and living organisms in the biosphere (see diagram at start of article). It includes movements of carbon between the atmosphere and terrestrial and marine ecosystems, as well as soils and seafloor sediments. The fast cycle includes annual cycles involving photosynthesis and decadal cycles involving vegetative growth and decomposition. The reactions of the fast carbon cycle to human activities will determine many of the more immediate impacts of climate change.


title: Carbon cycle

text: The slow carbon cycle involves medium to long-term geochemical processes belonging to the rock cycle (see diagram on the right). The exchange between the ocean and atmosphere can take centuries, and the weathering of rocks can take millions of years. Carbon in the ocean precipitates to the ocean floor where it can form sedimentary rock and be subducted into the earth's mantle. Mountain building processes result in the return of this geologic carbon to the Earth's surface. There the rocks are weathered and carbon is returned to the atmosphere by degassing and to the ocean by rivers. Other geologic carbon returns to the ocean through the hydrothermal emission of calcium ions. In a given year between 10 and 100 million tonnes of carbon moves around this slow cycle. This includes volcanoes returning geologic carbon directly to the atmosphere in the form of carbon dioxide. However, this is less than one percent of the carbon dioxide put into the atmosphere by burning fossil fuels.


title: Carbon cycle

text: Although deep carbon cycling is not as well-understood as carbon movement through the atmosphere, terrestrial biosphere, ocean, and geosphere, it is nonetheless an important process. The deep carbon cycle is intimately connected to the movement of carbon in the Earth's surface and atmosphere. If the process did not exist, carbon would remain in the atmosphere, where it would accumulate to extremely high levels over long periods of time. Therefore, by allowing carbon to return to the Earth, the deep carbon cycle plays a critical role in maintaining the terrestrial conditions necessary for life to exist.


title: Carbon cycle

text: Furthermore, the process is also significant simply due to the massive quantities of carbon it transports through the planet. In fact, studying the composition of basaltic magma and measuring carbon dioxide flux out of volcanoes reveals that the amount of carbon in the mantle is actually greater than that on the Earth's surface by a factor of one thousand. Drilling down and physically observing deep-Earth carbon processes is evidently extremely difficult, as the lower mantle and core extend from 660 to 2,891 km and 2,891 to 6,371  km deep into the Earth respectively. Accordingly, not much is conclusively known regarding the role of carbon in the deep Earth. Nonetheless, several pieces of evidence—many of which come from laboratory simulations of deep Earth conditions—have indicated mechanisms for the element's movement down into the lower mantle, as well as the forms that carbon takes at the extreme temperatures and pressures of said layer. Furthermore, techniques like seismology have led to a greater understanding of the potential presence of carbon in the Earth's core.


title: Carbon cycle

text: Carbon principally enters the mantle in the form of carbonate-rich sediments on tectonic plates of ocean crust, which pull the carbon into the mantle upon undergoing subduction. Not much is known about carbon circulation in the mantle, especially in the deep Earth, but many studies have attempted to augment our understanding of the element's movement and forms within the region. For instance, a 2011 study demonstrated that carbon cycling extends all the way to the lower mantle. The study analyzed rare, super-deep diamonds at a site in Juina, Brazil, determining that the bulk composition of some of the diamonds' inclusions matched the expected result of basalt melting and crytallisation under lower mantle temperatures and pressures. Thus, the investigation's findings indicate that pieces of basaltic oceanic lithosphere act as the principle transport mechanism for carbon to Earth's deep interior. These subducted carbonates can interact with lower mantle silicates, eventually forming super-deep diamonds like the one found.


title: Carbon cycle

text: However, carbonates descending to the lower mantle encounter other fates in addition to forming diamonds. In 2011, carbonates were subjected to an environment similar to that of 1800 km deep into the Earth, well within the lower mantle. Doing so resulted in the formations of magnesite, siderite, and numerous varieties of graphite. Other experiments—as well as petrologic observations—support this claim, indicating that magnesite is actually the most stable carbonate phase in most part of the mantle. This is largely a result of its higher melting temperature. Consequently, scientists have concluded that carbonates undergo reduction as they descend into the mantle before being stabilised at depth by low oxygen fugacity environments. Magnesium, iron, and other metallic compounds act as buffers throughout the process. The presence of reduced, elemental forms of carbon like graphite would indicate that carbon compounds are reduced as they descend into the mantle.


title: Carbon cycle

text: Polymorphism alters carbonate compounds' stability at different depths within the Earth. To illustrate, laboratory simulations and density functional theory calculations suggest that tetrahedrally coordinated carbonates are most stable at depths approaching the core–mantle boundary. A 2015 study indicates that the lower mantle's high pressure causes carbon bonds to transition from sp to sp hybridised orbitals, resulting in carbon tetrahedrally bonding to oxygen. CO trigonal groups cannot form polymerisable networks, while tetrahedral CO can, signifying an increase in carbon's coordination number, and therefore drastic changes in carbonate compounds' properties in the lower mantle. As an example, preliminary theoretical studies suggest that high pressure causes carbonate melt viscosity to increase; the melts' lower mobility as a result of its increased viscosity causes large deposits of carbon deep into the mantle.


title: Carbon cycle

text: Accordingly, carbon can remain in the lower mantle for long periods of time, but large concentrations of carbon frequently find their way back to the lithosphere. This process, called carbon outgassing, is the result of carbonated mantle undergoing decompression melting, as well as mantle plumes carrying carbon compounds up towards the crust. Carbon is oxidised upon its ascent towards volcanic hotspots, where it is then released as CO. This occurs so that the carbon atom matches the oxidation state of the basalts erupting in such areas.


title: Carbon cycle

text: Although the presence of carbon in the Earth's core is well-constrained, recent studies suggest large inventories of carbon could be stored in this region. Shear (S) waves moving through the inner core travel at about fifty percent of the velocity expected for most iron-rich alloys. Because the core's composition is believed to be an alloy of crystalline iron and a small amount of nickel, this seismic anomaly indicates the presence of light elements, including carbon, in the core. In fact, studies using diamond anvil cells to replicate the conditions in the Earth's core indicate that iron carbide (FeC) matches the inner core's wave speed and density. Therefore, the iron carbide model could serve as an evidence that the core holds as much as 67% of the Earth's carbon. Furthermore, another study found that in the pressure and temperature condition of the Earth's inner core, carbon dissolved in iron and formed a stable phase with the same FeC composition—albeit with a different structure from the one previously mentioned. In summary, although the amount of carbon potentially stored in the Earth's core is not known, recent studies indicate that the presence of iron carbides can explain some of the geophysical observations.