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Ghost Dance

The Ghost Dance (Caddo: Nanissáanah, also called the Ghost Dance of 1890) is a ceremony incorporated into numerous Native American belief systems. According to the teachings of the Northern Paiute spiritual leader Wovoka (renamed Jack Wilson), proper practice of the dance would reunite the living with spirits of the dead, bring the spirits to fight on their behalf, end American Westward expansion, and bring peace, prosperity, and unity to Native American peoples throughout the region.

The basis for the Ghost Dance is the circle dance, a traditional Native American dance. The Ghost Dance was first practiced by the Nevada Northern Paiute in 1889. The practice swept throughout much of the Western United States, quickly reaching areas of California and Oklahoma. As the Ghost Dance spread from its original source, different tribes synthesized selective aspects of the ritual with their own beliefs.

The Ghost Dance has been associated with Wovoka's prophecy of an end to colonial expansion while preaching goals of clean living, an honest life, and cross-cultural cooperation by Native Americans. Practice of the Ghost Dance movement was believed to have contributed to Lakota resistance to assimilation under the Dawes Act. The Lakota variation on the Ghost Dance tended towards millenarianism, an innovation that distinguished the Lakota interpretation from Jack Wilson's original teachings. The Caddo still practice the Ghost Dance today.

Paiute influence

The Northern Paiutes living in Mason Valley, in what is now the U.S. state of Nevada, were known collectively as the Tövusidökadö (lit. '(Cyperus) bulb eaters') at the time of European contact. The Northern Paiute community at this time was thriving upon a subsistence pattern of fishing, hunting wild game, and foraging for pine nuts and roots such as Cyperus esculentus.

The Tövusidökadö tended to follow various spiritual leaders and community organizers. Community events centered on the observance of seasonal ceremonies such as harvests or hunting. In 1869, Hawthorne Wodziwob, a Paiute man, organized a series of community dances to announce a vision. He spoke of a journey to the land of the dead and of promises made to him by the souls of the recently deceased. They promised to return to their loved ones within a period of three to four years.

Wodziwob's peers accepted this vision, likely due to his reputable status as a healer. He urged the populace to dance the common circle dance as was customary during a time of celebration. He continued preaching this message for three years with the help of a local "weather doctor" named Tavibo, father of Wovoka.

Prior to Wodziwob's religious movement, a devastating typhoid fever epidemic struck in 1867. This and other European diseases killed approximately one-tenth of the total population, resulting in widespread psychological and emotional trauma. The disruption brought disorder to the economic system and society. Many families were prevented from continuing their nomadic lifestyle.

Round Dance influence
A round dance is a circular community dance held usually around an individual who leads the ceremony. Round dances may be ceremonial or purely social. Usually, the dancers are accompanied by a group of singers who may also play hand drums in unison. The dancers join hands to form a large circle. The dancers move with a side-shuffle step to reflect the long-short pattern of the drum beat, bending their knees to emphasize the pattern.

During his studies of the Pacific Northwest tribes the anthropologist Leslie Spier used the term "prophet dances" to describe ceremonial round dances where the participants seek trance, exhortations and prophecy. Spier studied peoples of the Columbia plateau (a region including Washington, Oregon, Idaho, and parts of western Montana). By the time of his studies the only dances he was allowed to witness were social dances or ones that had already incorporated Christian elements, making investigation of the round dance's origin complicated.

The Prophet

Jack Wilson, the prophet otherwise known as Wovoka, was believed to have had a vision during a solar eclipse on January 1, 1889. It was reportedly not his first time experiencing a vision, but as a young adult, he claimed that he was then better equipped, spiritually, to handle this message. Jack had received training from an experienced holy man under his parents' guidance after they realized that he was having difficulty interpreting his previous visions. Jack was also training to be a "weather doctor", following in his father's footsteps. He was known throughout Mason Valley as a gifted and blessed young leader. Preaching a message of universal love, he often presided over circle dances, which symbolized the sun's heavenly path across the sky.

Anthropologist James Mooney conducted an interview with Wilson prior to 1892. Mooney confirmed that his message matched that given to his fellow Indians. This study compared letters between tribes. According to Mooney, Wilson's letter said he stood before God in heaven and had seen many of his ancestors engaged in their favorite pastimes, and that God showed Wilson a beautiful land filled with wild game and instructed him to return home to tell his people that they must love each other and not fight. He also stated that Jesus was being reincarnated on Earth in 1892, that the people must work, not steal or lie, and that they must not engage in the old practices of war or the traditional self-mutilation practices connected with mourning the dead. He said that if his people abided by these rules, they would be united with their friends and family in the other world, and in God's presence, there would be no sickness, disease, or old age.

Mooney writes that Wilson was given the Ghost Dance and commanded to take it back to his people. He preached that if the five-day dance was performed in the proper intervals, the performers would secure their happiness and hasten the reunion of the living and deceased. Wilson said that the Creator gave him powers over the weather and that he would be the deputy in charge of affairs in the western United States, leaving current President Harrison as God's deputy in the East. Jack claims that he was then told to return home and preach God's message.

Jack Wilson claimed to have left the presence of God convinced that if every Indian in the West danced the new dance to "hasten the event", all evil in the world would be swept away, leaving a renewed Earth filled with food, love, and faith. Quickly accepted by his Paiute brethren, the new religion was termed, "Dance In A Circle". Because the first European contact with the practice came by way of the Lakota, their expression "Spirit Dance" was adopted as a descriptive title for all such practices. This was subsequently translated as "Ghost Dance".

Spread of the prophet's message

Through Native Americans and some white settlers, Wilson's message spread across much of the western portion of the United States. Early in the religious movement, many tribes sent members to investigate the self-proclaimed prophet, while other communities sent delegates only to be cordial. Regardless of their initial motivations, many left as believers and returned to their homeland preaching his message. The Ghost Dance was also investigated by many Mormons from Utah, for whom the concepts of the Indian prophet were familiar and often accepted. While many followers of the Ghost Dance believed Wovoka to be a teacher of pacifism and peace, others did not.

An elaboration of the Ghost Dance concept was the development of ghost shirts, which were special clothing that warriors could wear. They were rumored to repel bullets through spiritual power. It is uncertain where this belief originated. Scholars believe that in 1890 Chief Kicking Bear introduced the concept to his people, the Lakota, while James Mooney argued that the most likely source is the Mormon temple garment (which Mormons believe protect the pious wearer from evil).

The Lakota interpretation drew from their traditional idea of a "renewed Earth" in which "all evil is washed away". This Lakota interpretation included the removal of all European Americans from their lands: "They told the people they could dance a new world into being. There would be landslides, earthquakes, and big winds. Hills would pile up on each other. The earth would roll up like a carpet with all the white man's ugly things – the stinking new animals, sheep and pigs, the fences, the telegraph poles, the mines and factories. Underneath would be the wonderful old-new world as it had been before the white fat-takers came. ...The white men will be rolled up, disappear, go back to their own continent. (p. 228)"

- Lame Deer

Political influence
In February 1890, the United States government broke a Lakota treaty by adjusting the Great Sioux Reservation of South Dakota (an area that formerly encompassed the majority of the state) and breaking it up into five smaller reservations. The government was accommodating white homesteaders from the eastern United States; in addition, it intended to "break up tribal relationships" and "conform Indians to the white man's ways, peaceably if they will, or forcibly if they must". On the reduced reservations, the government allocated family units on 320 acre plots for individual households. The Lakota were expected to farm and raise livestock, and to send their children to boarding schools. With the goal of assimilation, the schools taught English and Christianity, as well as American cultural practices. Generally, they forbade inclusion of Indian traditional cultures and languages.

To help support the Lakota during the period of transition, the Bureau of Indian Affairs (BIA) was to supplement the Lakota with food and to hire white farmers as teachers for the people. The farming plan failed to take into account the difficulty that Lakota farmers would have in trying to cultivate crops in the semi-arid region of South Dakota. By the end of the 1890 growing season, a time of intense heat and low rainfall, it was clear that the land was unable to produce substantial agricultural yields. Unfortunately, this was also the time when the government's patience with supporting the so-called "lazy Indians" ran out. They cut rations for the Lakota in half. With the bison having been virtually eradicated a few years earlier, the Lakota were at risk of starvation.

The people turned to the Ghost Dance ritual, which frightened the supervising agents of the BIA. Those who had been residing in the area for a long time recognized that the ritual was often held shortly before battle was to occur. Kicking Bear was forced to leave Standing Rock, but when the dances continued unabated, Agent James McLaughlin asked for more troops. He claimed the Hunkpapa spiritual leader Sitting Bull was the real leader of the movement. A former agent, Valentine McGillycuddy, saw nothing extraordinary in the dances and ridiculed the panic that seemed to have overcome the agencies, saying:

"The coming of the troops has frightened the Indians. If the Seventh-day Adventists prepare the ascension robes for the Second Coming of the Savior, the United States Army is not put in motion to prevent them. Why should not the Indians have the same privilege? If the troops remain, trouble is sure to come."

Nonetheless, thousands of additional U.S. Army troops were deployed to the reservation. On December 15, 1890, Sitting Bull was arrested for failing to stop his people from practicing the Ghost Dance. During the incident, one of Sitting Bull's men, Catch the Bear, fired at Lieutenant "Bull Head", striking his right side. He instantly wheeled and shot Sitting Bull, hitting him in the left side, between the tenth and eleventh ribs; this exchange resulted in deaths on both sides, including that of Sitting Bull.

Wounded Knee
Spotted Elk (Lakota: Unpan Glešká – also known as Big Foot) was a Miniconjou leader on the U.S. Army's list of 'trouble-making' Indians. On December 29, 1890, he was stopped while en route to convene with the remaining Lakota chiefs. U.S. Army officers forced him to relocate with his people to a small camp close to the Pine Ridge Agency. Here the soldiers could more closely watch the old chief. That evening, December 28, the small band of Lakota erected their tipis on the banks of Wounded Knee Creek. The following day, during an attempt by the officers to collect weapons from the band, one young, deaf Lakota warrior refused to relinquish his arms. A struggle followed in which somebody's weapon discharged into the air. One U.S. officer gave the command to open fire, and the Lakota responded by taking up previously confiscated weapons; the U.S. forces responded with carbine firearms and several rapid-fire light-artillery Hotchkiss guns mounted on the overlooking hill. When the fighting had concluded, 25 U.S. soldiers lay dead, many killed by friendly fire. Among the 153 dead Lakota, most were women and children. Following the massacre, Chief Kicking Bear officially surrendered his weapon to General Nelson A. Miles.

Aftermath
Twenty U.S. soldiers received Medals of Honor for their actions (some sources state the number as 18 or 23). American Indian and human rights activists have referred to these as "Medals of Dis-Honor" and called for the awards to be rescinded, but none of them have ever been revoked.

Following the Wounded Knee Massacre, open participation in the Ghost Dance movement declined gradually for fear of continued violence against practitioners. Like most Indian ceremonies, it became clandestine rather than dying out completely.

Congress officially apologized for the Wounded Knee Massacre in 1990 but did not rescind any medals of honor at that time.

Rejection
Despite the widespread acceptance of the Ghost Dance movement, Navajo leaders described the Ghost Dance as "worthless words" in 1890. Three years later, James Mooney arrived at the Navajo reservation in northern Arizona during his study of the Ghost Dance movement and found the Navajo never incorporated the ritual into their society.

Kehoe believed the movement did not gain traction with the tribe due to the Navajo's higher levels of social and economic satisfaction at the time. Another factor was cultural norms among the Navajo, which inculcated a fear of ghosts and spirits, based on religious beliefs.

Today
The Wounded Knee massacre was not the end of the Ghost Dance religious movement. Instead, it went underground. Wovoka continued to spread its message, along with Kicking Bear, Short Bull and other spiritual leaders.

During the Wounded Knee incident of 1973, Lakota men and women, including Mary Brave Bird, did the ghost dance ceremony on the site where their ancestors had been killed. In her book Lakota Woman, Brave Bird wrote that ghost dances continue as private ceremonies.

title: Ghost Dance


text: Talk:Ghost Dance

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

title: Talk:Ghost Dance


text:
Huygens (spacecraft)

Huygens was an atmospheric entry robotic  space probe that landed successfully on Saturn's moon Titan in 2005. Built and operated by the European Space Agency (ESA), launched by NASA, it was part of the Cassini–Huygens mission and became the first spacecraft to land on Titan and the farthest landing from Earth a spacecraft has ever made. The probe was named after the 17th-century Dutch astronomer Christiaan Huygens, who discovered Titan in 1655.

The combined Cassini–Huygens spacecraft was launched from Earth on 15 October 1997. Huygens separated from the Cassini orbiter on 25 December 2004, and landed on Titan on 14 January 2005 near the Adiri region. Huygens's landing is so far the only one accomplished in the outer Solar System or on a moon other than Earth's.

Huygens touched down on land, although the possibility that it would touch down in an ocean was also taken into account in its design. The probe was designed to gather data for a few hours in the atmosphere, and possibly a short time at the surface. It continued to send data for about 90 minutes after touchdown.

Overview
Huygens was designed to enter and brake in Titan's atmosphere and parachute a fully instrumented robotic laboratory to the surface. When the mission was planned, it was not yet certain whether the landing site would be a mountain range, a flat plain, an ocean, or something else, and it was thought that analysis of data from Cassini would help to answer these questions.

Based on pictures taken by Cassini 1200 km above Titan, the landing site appeared to be a shoreline. Assuming the landing site could be non-solid, Huygens was designed to survive the impact, splash down on a liquid surface on Titan, and send back data for several minutes under these conditions. If that occurred it was expected to be the first time a human-made probe would land in an extraterrestrial ocean. The spacecraft had no more than three hours of battery life, most of which was planned to be used during the descent. Engineers expected to get at most only 30 minutes of data from the surface.

The Huygens probe system consists of the 318 kg probe itself, which descended to Titan, and the 30 kg kg probe support equipment (PSE), which remained attached to the orbiting spacecraft. Huygens ' heat shield was 2.7 m in diameter. After ejecting the shield, the probe was 1.3 m in diameter. The PSE included the electronics necessary to track the probe, to recover the data gathered during its descent, and to process and deliver the data to the orbiter, from where it was transmitted or "downlinked" to the Earth.

The probe remained dormant throughout the 6.7-year interplanetary cruise, except for semiannual health checks. These checkouts followed preprogrammed descent scenario sequences as closely as possible, and the results were relayed to Earth for examination by system and payload experts.

Prior to the probe's separation from the orbiter on 25 December 2004, a final health check was performed. The "coast" timer was loaded with the precise time necessary to turn on the probe systems (15 minutes before its encounter with Titan's atmosphere), then the probe detached from the orbiter and coasted in free space to Titan in 22 days with no systems active except for its wake-up timer.

The main mission phase was a parachute descent through Titan's atmosphere. The batteries and all other resources were sized for a Huygens mission duration of 153 minutes, corresponding to a maximum descent time of 2.5 hours plus at least 3 additional minutes (and possibly a half-hour or more) on Titan's surface. The probe's radio link was activated early in the descent phase, and the orbiter "listened" to the probe for the next three hours, including the descent phase, and the first thirty minutes after touchdown. Not long after the end of this three-hour communication window, Cassini ' s high-gain antenna (HGA) was turned away from Titan and towards Earth.

Very large radio telescopes on Earth were also listening to Huygens 's 10-watt transmission using the technique of very long baseline interferometry and aperture synthesis mode. At 11:25 CET on 14 January, the Robert C. Byrd Green Bank Telescope (GBT) in West Virginia detected the carrier signal from Huygens. The GBT continued to detect the carrier signal well after Cassini stopped listening to the incoming data stream. In addition to the GBT, eight of the ten telescopes of the continent-wide VLBA in North America, located at Pie Town and Los Alamos, New Mexico; Fort Davis, Texas; North Liberty, Iowa; Kitt Peak, Arizona; Brewster, Washington; Owens Valley, California; and Mauna Kea, Hawaii, also listened for the Huygens signal.

The signal strength received on Earth from Huygens was comparable to that from the Galileo probe (the Jupiter atmospheric descent probe) as received by the VLA, and was therefore too weak to detect in real time because of the signal modulation by the (then) unknown telemetry. Instead, wide-band recordings of the probe signal were made throughout the three-hour descent. After the probe telemetry was finished being relayed from Cassini to Earth, the now-known data modulation was stripped off the recorded signal, leaving a pure carrier that could be integrated over several seconds to determine the probe frequency. It was expected that through analysis of the Doppler shifting of Huygens ' s signal as it descended through the atmosphere of Titan, wind speed and direction could be determined with some degree of accuracy. A position of Huygens's landing site on Titan was found with precision (within one km – one km on Titan measures 1.3 arcminutes of latitude and longitude at the equator) using the Doppler data at a distance from Earth of about 1.2 billion kilometers. The probe landed on the surface of the moon at -10.573°N, -192.335°W. A similar technique was used to determine the landing site of the Mars exploration rovers by listening to their telemetry alone.

Findings
Huygens landed at around 12:43 UTC on January 14, 2005 with an impact speed similar to dropping a ball on Earth from a height of about 1 m. It made a dent 12 cm deep, before bouncing onto a flat surface, and sliding 30 to 40 cm across the surface. It slowed due to friction with the surface and, upon coming to its final resting place, wobbled back and forth five times. Huygens' sensors continued to detect small vibrations for another two seconds, until motion subsided about ten seconds after touchdown. The probe kicked up a cloud of dust (most likely organic aerosols which drizzle out of the atmosphere) which remained suspended in the atmosphere for about four seconds by the impact.

At the landing site there were indications of pebbles of water ice scattered over an orange surface, the majority of which is covered by a thin haze of methane. Early aerial imaging of Titan from Huygens was consistent with the presence of large bodies of liquid on the surface. The initial photos of Titan before landing showed what appeared to be large drainage channels crossing the lighter colored mainland into a dark sea. Some of the photos suggested islands and a mist shrouded coastline. Subsequent analysis of the probe's trajectory indicated that, in fact, Huygens had landed within the dark 'sea' region in the photos. The photos from the surface of a dry lakebed like landscape suggest that while there is evidence of liquid acting on the surface recently, hydrocarbon lakes and/or seas might not currently exist at the Huygens landing site. Further data from the Cassini Mission, however, definitely confirmed the existence of permanent liquid hydrocarbon lakes in the polar regions of Titan (see Lakes of Titan). Long-standing tropical hydrocarbon lakes were also discovered in 2012 (including one not far from the Huygens landing site in the Shangri-La region which is about half the size of Utah's Great Salt Lake, with a depth of at least 1 m). The likely supplier in dry desert areas is probably underground aquifers; in other words, the arid equatorial regions of Titan contain "oases".

The surface was initially reported to be a clay-like "material which might have a thin crust followed by a region of relative uniform consistency." One ESA scientist compared the texture and colour of Titan's surface to a crème brûlée (that is, a hard surface covering a sticky mud-like subsurface). Subsequent analysis of the data suggests that surface consistency readings were likely caused by Huygens pushing a large pebble into the ground as it landed, and that the surface is better described as a "sand" made of ice grains or snow that has been frozen on top. The images taken after the probe's landing show a flat plain covered in pebbles. The pebbles, which may be made of hydrocarbon-coated water ice, are somewhat rounded, which may indicate the action of fluids on them. The rocks appear to be rounded, size-selected and size-layered as though located in the bed of a stream within a dark lakebed, which consists of finer-grained material. No pebbles larger than 15 cm across were spotted, while rocks smaller than 5 cm are rare on the Huygens landing site. This implies large pebbles cannot be transported to the lakebed, while small rocks are quickly removed from the surface.

The temperature at the landing site was 93.8 K and pressure of 1467.6 mbar, implying a methane abundance of 5 ± 1% and methane relative humidity of 50% near the surface. Therefore, ground fogs caused by methane in the neighborhood of the landing site are unlikely. Thermometers indicated that heat left Huygens so quickly that the ground must have been damp, and one image shows light reflected by a dewdrop as it falls across the camera's field of view. On Titan, the feeble sunlight allows only about one centimeter of evaporation per year (versus one metre of water on Earth), but the atmosphere can hold the equivalent of about 10 m of liquid before rain forms vs. only a few centimeters on Earth. So Titan's weather is expected to feature torrential downpours causing flash floods, interspersed by decades or centuries of drought.

Huygens found the brightness of the surface of Titan (at time of landing) to be about one thousand times dimmer than full solar illumination on Earth (or 500 times brighter than illumination by full moonlight)—that is, the illumination level experienced about ten minutes after sunset on Earth, approximately late civil twilight. The color of the sky and the scene on Titan is mainly orange due to the much greater attenuation of blue light by Titan's haze relative to red light. The Sun (which was comparatively high in the sky when Huygens landed) would be visible as a small, bright spot, one tenth the size of the solar disk seen from Earth, and comparable in size and brightness to a car headlight seen from about 150 m. It casts sharp shadows, but of low contrast as 90% of the illumination comes from the sky.

Detailed Huygens activity timeline

 * Huygens separated from Cassini orbiter at 02:00 UTC on 25 December 2004 in Spacecraft Event Time.
 * Huygens entered Titan's atmosphere at 10:13 UTC on 14 January 2005 in SCET, according to ESA.
 * The probe landed on the surface of Titan at about 10.6°S, 192.3°W around 12:43 UTC in SCET (2 hours 30 minutes after atmospheric entry).(1.)

There was a transit of the Earth and Moon across the Sun as seen from Saturn/Titan just hours before the landing. Huygens entered the upper layer of Titan's atmosphere 2.7 hours after the end of the transit of the Earth, or only one or two minutes after the end of the transit of the Moon. However, the transit did not interfere with the Cassini orbiter or Huygens probe, for two reasons. First, although they could not receive any signal from Earth because it was in front of the Sun, Earth could still listen to them. Second, Huygens did not send any readable data directly to Earth. Rather, it transmitted data to the Cassini orbiter, which later relayed to Earth the data received.

Instrumentation
Huygens had six instruments aboard that took in a wide range of scientific data as the probe descended through Titan's atmosphere. The six instruments are:

Huygens Atmospheric Structure Instrument (HASI)
This instrument contains a suite of sensors that measured the physical and electrical properties of Titan's atmosphere. Accelerometers measured forces in all three axes as the probe descended through the atmosphere. With the aerodynamic properties of the probe already known, it was possible to determine the density of Titan's atmosphere and to detect wind gusts. The probe was designed so that in the event of a landing on a liquid surface, its motion due to waves would also have been measurable. Temperature and pressure sensors measured the thermal properties of the atmosphere. The Permittivity and Electromagnetic Wave Analyzer component measured the electron and ion (i.e., positively charged particle) conductivities of the atmosphere and searched for electromagnetic wave activity. On the surface of Titan, the electrical conductivity and permittivity (i.e., the ratio of electric displacement field to its electric field) of the surface material was measured. The HASI subsystem also contains a microphone, which was used to record any acoustic events during probe's descent and landing;

Doppler Wind Experiment (DWE)
This experiment used an ultra-stable oscillator which provided a precise S-band carrier frequency that allowed the Cassini orbiter to accurately determine Huygens's radial velocity with respect to Cassini via the Doppler Effect. The wind-induced horizontal motion from Huygens would have been derived from the measured Doppler shift measurements, corrected for all known orbit and propagation effects. The swinging motion of the probe beneath its parachute due to atmospheric properties may also have been detected. Failure of ground controllers to turn on the receiver in the Cassini orbiter caused the loss of this data. Earth-based radio telescopes were able to reconstruct some of it. Measurements started 150 km above Titan's surface, where Huygens was blown eastwards at more than 400 kph, agreeing with earlier measurements of the winds at 200 km altitude, made over the past few years using telescopes. Between 60 and 80 km, Huygens was buffeted by rapidly fluctuating winds, which are thought to be vertical wind shear. At ground level, the Earth-based doppler shift and VLBI measurements show gentle winds of a few metres per second, roughly in line with expectations.

Descent Imager/Spectral Radiometer (DISR)
As Huygens was primarily an atmospheric mission, the DISR instrument was optimized to study the radiation balance inside Titan's atmosphere. Its visible and infrared spectrometers and violet photometers measured the up- and downward radiant flux from an altitude of 145 km down to the surface. Solar aureole cameras measured how scattering by aerosols varies the intensity directly around the Sun. Three imagers, sharing the same CCD, periodically imaged a swath of around 30 degrees wide, ranging from almost nadir to just above the horizon. Aided by the slowly spinning probe they would build up a full mosaic of the landing site, which, surprisingly, became clearly visible only below 25 km altitude. All measurements were timed by aid of a shadow bar, which would tell DISR when the Sun had passed through the field of view. Unfortunately, this scheme was upset by the fact that Huygens rotated in a direction opposite to that expected. Just before landing a lamp was switched on to illuminate the surface, which enabled measurements of the surface reflectance at wavelengths which are completely blocked out by atmospheric methane absorption.

DISR was developed at the Lunar and Planetary Laboratory at the University of Arizona under the direction of Martin Tomasko, with several European institutes contributing to the hardware. "The scientific objectives of the experiment fall into four areas including (1) measurement of the solar heating profile for studies of the thermal balance of Titan; (2) imaging and spectral reflection measurements of the surface for studies of the composition, topography, and physical processes which form the surface as well as for direct measurements of the wind profile during the descent; (3) measurements of the brightness and degree of linear polarization of scattered sunlight including the solar aureole together with measurements of the extinction optical depth of the aerosols as a function of wavelength and altitude to study the size, shape, vertical distribution, optical properties, sources and sinks of aerosols in Titan’s atmosphere; and (4) measurements of the spectrum of downward solar flux to study the composition of the atmosphere, especially the mixing ratio profile of methane throughout the descent."

Gas Chromatograph Mass Spectrometer (GC/MS)
This instrument is a gas chemical analyzer that was designed to identify and measure chemicals in Titan's atmosphere. It was equipped with samplers that were filled at high altitude for analysis. The mass spectrometer, a high-voltage quadrupole, collected data to build a model of the molecular masses of each gas, and a more powerful separation of molecular and isotopic species was accomplished by the gas chromatograph. During descent, the GC/MS also analyzed pyrolysis products (i.e., samples altered by heating) passed to it from the Aerosol Collector Pyrolyser. Finally, the GC/MS measured the composition of Titan's surface. This investigation was made possible by heating the GC/MS instrument just prior to impact in order to vaporize the surface material upon contact. The GC/MS was developed by Goddard Space Flight Center and the University of Michigan's Space Physics Research Lab.

Aerosol Collector and Pyrolyser (ACP)
The ACP experiment drew in aerosol particles from the atmosphere through filters, then heated the trapped samples in ovens (using the process of pyrolysis) to vaporize volatiles and decompose the complex organic materials. The products were flushed along a pipe to the GC/MS instrument for analysis. Two filters were provided to collect samples at different altitudes. The ACP was developed by a (French) ESA team at the Laboratoire Inter-Universitaire des Systèmes Atmosphériques (LISA).

Surface Science Package (SSP)
The SSP contained a number of sensors designed to determine the physical properties of Titan's surface at the point of impact, whether the surface was solid or liquid. An acoustic sounder, activated during the last 100 m of the descent, continuously determined the distance to the surface, measuring the rate of descent and the surface roughness (e.g., due to waves). The instrument was designed so that if the surface were liquid, the sounder would measure the speed of sound in the "ocean" and possibly also the subsurface structure (depth). During descent, measurements of the speed of sound gave information on atmospheric composition and temperature, and an accelerometer recorded the deceleration profile at impact, indicating the hardness and structure of the surface. A tilt sensor measured pendulum motion during the descent and was also designed to indicate the probe's attitude after landing and show any motion due to waves. If the surface had been liquid, other sensors would also have measured its density, temperature, thermal conductivity, heat capacity, electrical properties (permittivity and conductivity) and refractive index (using a critical angle refractometer). A penetrometer instrument, that protruded 55 mm past the bottom of the Huygens descent module, was used to create a penetrometer trace as Huygens landed on the surface. This was done by measuring the force exerted on the instrument by the body's surface as it broke through and was pushed down into the body by the landing. The trace shows this force as a function of time over a period of about 400 ms. The trace has an initial spike which suggests that the instrument hit one of the icy pebbles on the surface photographed by the DISR camera.

The Huygens SSP was developed by the Space Sciences Department of the University of Kent and the Rutherford Appleton Laboratory Space Science Department (now RAL Space) under the direction of Professor John Zarnecki. The SSP research and responsibility transferred to the Open University when John Zarnecki transferred in 2000.

Spacecraft design

Huygens was built under the Prime Contractorship of Aérospatiale in its Cannes Mandelieu Space Center, France, now part of Thales Alenia Space. The heat shield system was built under the responsibility of Aérospatiale near Bordeaux, now part of Airbus Defence and Space.

Parachute
Martin-Baker Space Systems was responsible for Huygens' parachute systems and the structural components, mechanisms and pyrotechnics that control the probe's descent onto Titan. IRVIN-GQ was responsible for the definition of the structure of each of Huygens ' parachutes. Irvin worked on the probe's descent control sub-system under contract to Martin-Baker Space Systems.

Critical design flaw partially resolved
Long after launch, a few persistent engineers discovered that the communication equipment on Cassini had a potentially fatal design flaw, which would have caused the loss of all data transmitted by Huygens.

Since Huygens was too small to transmit directly to Earth, it was designed to transmit the telemetry data obtained while descending through Titan's atmosphere by radio to Cassini, which would in turn relay it to Earth using its large 4 m diameter main antenna. Some engineers, most notably ESA ESOC employees Claudio Sollazzo and Boris Smeds, felt uneasy about the fact that, in their opinion, this feature had not been tested before launch under sufficiently realistic conditions. Smeds managed, with some difficulty, to persuade superiors to perform additional tests while Cassini was in flight. In early 2000, he sent simulated telemetry data at varying power and Doppler shift levels from Earth to Cassini. It turned out that Cassini was unable to relay the data correctly.

This was because under the original flight plan, when Huygens was to descend to Titan, it would have accelerated relative to Cassini, causing the Doppler shift of its signal to vary. Consequently, the hardware of Cassini's receiver was designed to be able to receive over a range of shifted frequencies. However, the firmware failed to take into account that the Doppler shift would have changed not only the carrier frequency, but also the timing of the payload bits, coded by phase-shift keying at 8192 bits per second.

Reprogramming the firmware was impossible, and as a solution the trajectory had to be changed. Huygens detached a month later than originally planned (December 2004 instead of November) and approached Titan in such a way that its transmissions travelled perpendicular to its direction of motion relative to Cassini, greatly reducing the Doppler shift.

The trajectory change overcame the design flaw for the most part, and data transmission succeeded, although the information from one of the two radio channels was lost due to an unrelated error.

Channel A data loss
Huygens was programmed to transmit telemetry and scientific data to the Cassini orbiter for relay to Earth using two redundant S-band radio systems, referred to as Channel A and B, or Chain A and B. Channel A was the sole path for an experiment to measure wind speeds by studying tiny frequency changes caused by Huygens ' s motion. In one other deliberate departure from full redundancy, pictures from the descent imager were split, with each channel carrying 350 pictures.

Cassini never listened to channel A because of an error in the sequence of commands sent to the spacecraft. The receiver on the orbiter was never commanded to turn on, according to officials with the European Space Agency. ESA announced that the error was a mistake on their part, the missing command was part of a command sequence developed by ESA for the Huygens mission, and that it was executed by Cassini as delivered.

Because Channel A was not used, only 350 pictures were received instead of the 700 planned. All Doppler radio measurements between Cassini and Huygens were lost as well. Doppler radio measurements of Huygens from Earth were made, although they were not as accurate as the lost measurements that Cassini made. The use of accelerometer sensors on Huygens and VLBI tracking of the position of the Huygens probe from Earth allowed reasonably accurate wind speed and direction calculations to be made.

Contributions from citizen science projects
The fact that Huygens rotated in the opposite direction than planned delayed the creation of surface mosaics from the raw data by the project team for many months. On the other hand, this provided an opportunity for some citizen science projects to attempt the task of assembling the surface mosaics. This was possible, because the European Space Agency approved the publication of the DISR raw images and gave the permission for citizen scientists to present their results on the internet. Some of these citizen science projects have received a lot of attention in the scientific community, in popular scientific journals and in the public media. While the media liked to present the story of amateurs outperforming the professionals, most of the participants understood themselves as citizen scientists, and the driving force behind their work was a desire to find out and show as much as possible of the hitherto unknown surface of Titan. Some enthusiasts projects were the first at all to publish surface mosaics and panoramas of Titan already the day after Huygens landed, another project worked with the Huygens DISR data for several months until virtually all images with recognizable structures could be assigned to their correct position, resulting in comprehensive mosaics and panoramas. A surface panorama from this citizen science project was finally published in the context of a Nature review by Joseph Burns.

Landing site
The probe landed on the surface of Titan at -10.573°N, -192.335°W.

title: Huygens (spacecraft)


text:
Stonewall Jackson (singer)

Stonewall Jackson (November 6, 1932 – December 4, 2021) was an American country music singer and musician who achieved his greatest fame during country's "golden" honky tonk era in the 1950s and early 1960s.

Early years
Born in Tabor City, North Carolina on November 6, 1932, Jackson was the youngest of three children. Stonewall is not a nickname; he was named after Confederate General Thomas "Stonewall" Jackson. (Some publicity claimed he was a descendant of the general, but that is unlikely.)

When Stonewall was two, his father died after which his mother moved the family to Worth County in South Georgia, where he grew up working on his uncle's farm. Jackson enlisted in the Navy in 1950 and was discharged in 1954. He moved to Nashville, Tennessee in 1956.

Recording career
After hearing Jackson's demo tape, Wesley Rose, president of Acuff-Rose Music, arranged for Jackson to audition for the Grand Ole Opry. Jackson became the first artist to join the Grand Ole Opry before obtaining a recording contract. He toured with Ernest Tubb, who became his mentor. Jackson signed with Columbia Records in 1958.

His breakthrough came in the country Top 40 in late 1958, with a song written by a young George Jones, "Life to Go". It peaked at No.2 in early 1959 and his follow-up record, "Waterloo", was No.1 for five weeks, and crossed over into the Top 40 of the Billboard Hot 100 chart, where it reached No. 4. The track also reached No. 24 in the UK Singles Chart in July 1959. It sold over one million copies, and was awarded a gold disc. The song was a haunting and catchy tune that states "Everybody has to meet his Waterloo", meaning their fate. The song cites Adam, Napoleon and Tom Dooley as examples.

His next No. 1 hits came in 1964 with "Don't Be Angry" and "B.J. the D.J." (Jackson's foray into the teenage tragedy song trope, about an over-worked country music radio station disc jockey, who crashes his car in a rainstorm). In 1971, Jackson was the first artist to record a live album from the Grand Ole Opry with Recorded Live At The Grand Ole Opry. His other hit songs include "The Carpet on the Floor", "Why I'm Walkin'", "A Wound Time Can't Erase", and "I Washed My Hands In Muddy Water". Jackson also recorded a cover version of Lobo's 1971 hit, "Me and You and a Dog Named Boo", which became Jackson's final top 10 hit.

From 1958 to 1971, Jackson had 35 Top 40 country hits.

Later years
In 2006, Jackson sued the Grand Ole Opry for $10 million in compensatory damages and $10 million in punitive damages, claiming age discrimination. As a member of the Opry for over fifty years, Jackson believed management was sidelining him in favor of younger artists. In his court filing, Jackson claimed that Opry general manager Pete Fisher stated that he did not "want any gray hairs on that stage or in the audience, and before I'm done there won't be any." Fisher is also alleged to have told Jackson that he was "too old and too country". The lawsuit was settled on October 3, 2008 for an undisclosed amount and Jackson returned to performing on the show. He was a member of the Opry from 1956 until his death. He largely retired from performing by 2012, with his last public performance being at the funeral of his longtime friend George Jones.

Jackson lived on a farm in Brentwood, Tennessee where his wife Juanita died on January 11, 2019. She was also his personal manager and operated his song publishing company, Turp Tunes. He has a son, Stonewall Jackson Jr.

He was inducted into the North Carolina Music Hall of Fame on October 11, 2012.

Jackson died in Nashville, Tennessee, on December 4, 2021, at the age of 89, from complications of vascular dementia.

title: Stonewall Jackson (singer)


text:
Maricarmen Regueiro

María del Carmen Regueiro Lorenzo (born November 22, 1966, in Los Teques, Venezuela) better known as Maricarmen Regueiro is a former Venezuelan actress. As of 2001, she is no longer a public figure.

Biography
María del Carmen Regueiro Lorenzo was born on November 22, 1966, in Los Teques, Venezuela. She is the daughter of Spanish parents from Galicia, who came to Venezuela in search of a better future with the purpose of trying their luck in the jewelry business years ago. She has one sister and three brothers.

Personal life
In 2002, she gave birth to the couple's first child, a boy, whom they called Nicolás Helmeyer Regueiro. In 2003, she gave birth to the couple's second child, a girl whom they called Daniela Helmeyer Regueiro. When her sister died in an accident, she took care of her nephews and assumed the role of an adoptive mother.

Career
María del Carmen Regueiro began acting in Spanish language soap operas in 1986 when she participated in Cristal and the miniseries Mansion de Luxe alongside another famous Venezuelan actor, Carlos Mata. But she toiled as a secondary soap actress until 1988, when she starred in Señora alongside Carlos Mata, Flavio Caballero and Caridad Canelón. Señora became an instant hit all over Venezuela and other Latin American countries for producer RCTV and Regueiro became a super-star immediately. In Amanda Sabater alongside Flavio Caballero. In addition to working in Venezuelan and Peruvian productions she has also worked in Argentina.

title: Maricarmen Regueiro


text:
Ifni

Ifni was a Spanish province on the Atlantic coast of Morocco, south of Agadir and across from the Canary Islands. It had a total area of 1,502 km2, and a population of 51,517 in 1964. The main industry was fishing. The present-day Moroccan province in the same area is called Sidi Ifni, with its capital in the city of the same name, but encompassing a much larger territory.

History
Spain's presence in the area can be traced to a settlement called Santa Cruz de la Mar Pequeña, founded in 1476. After attacks by the Berbers, the Spanish decided to focus on colonising other areas of North Africa and abandoned the region.

In the mid-19th century, when the European powers looked again to Africa for resources, Spain suddenly mooted an interest in its lost late medieval fortress in order to stake a claim to the southern part of Morocco. This served as a pretext for a short war with Morocco in 1859.

The territory and its main town of Sidi Ifni were ceded to Spain by the Sultanate of Morocco on 26 April 1860, but there was little interest in this colonial acquisition until 1934, when the Governor-General of Spanish Sahara took up residence. The airport had become a crucial stopover for flights between the mainland and the Canary Islands, and in 1938 a commercial route was established by airline Iberia linking Seville, Larache, Sidi Ifni, Cape Juby and Gando in the Canaries.

The origin of Ifni must be dated to 1934, after Colonel Osvaldo Capaz took possession of the area, on behalf of the Government of the Second Spanish Republic. At that time, there was only a small construction, an aduar called Amezdog, belonging to the El Mesti Kabyle of the Ait-Baamarani Berber tribe, and of which there are currently no remnants.

Ifni's occupation took place after satisfactory contacts between Colonel Capaz and representatives of the population of the territory, with conversations carried out in Cape Juby on March the 27th of 1934. Then, on April 4, after receiving authorization from the Spanish Government, said colonel embarked on the Canalejas gunboat towards Ifni. On that date, a three-engine unit dropped a letter from Capaz in the Arbaa de Mesti souk, announcing the agreements adopted and the next Spanish landing. The event was related thus by Francisco Hernández-Pacheco, who was part of the scientific expedition that traveled over the territory of Ifni shortly after:"Capaz landed on the beach of Sidi Ifni on April 6, accompanied only by Lieutenant Lorenzi and the signalman from Canalejas, Fernando Gómez Flórez. To meet the Spanish boat, a row-boat with local people left the beach, to which Capaz and his crew transferred, all of them landing safely on the beach. Capaz addressed a group of indigenous people who were waiting for him, from which some notable stood out, and who offered the Colonel a bowl of sour milk as a welcome sign. Later, on horseback, he ascended to the top of the coastal area and in the immediate hamlet of Amedog (sic) he ate. During the meal some groups of indigenous and notable people arrived, to whom Capaz explained simply and clearly the purposes and intentions of Spain. The locals left after the meal, convening to hold meetings to discuss the matter. The following morning they informed Colonel Capaz of Ifni's agreement to join Spain. Francisco Hernández-Pacheco, Physiographic and geological features of the Ifni territory."Together with Amezdog, the Spanish presence was formalized in a ceremony attended by notable Baamaranis and Colonel Osvaldo Capaz.

In just three years it went from an occasional tent camp, and some barracks, to the construction of six hundred houses or buildings. Indeed, the population experienced spectacular growth in just a few years. By 1940 the urban structure was already well advanced in its streets, squares and main buildings. However, for some years communication with the metropolis was difficult. The city did not stop growing in all subsequent years. Even just three short years before the 1969 retrocession to Morocco, the most considerable urban expansion was concluded, on the other side of the Ifni river, in the neighborhood popularly known as "Barrio Agulla" or, more commonly, "Colominas" (name of the Spanish construction company of the neighborhood).

After Moroccan independence, the Moroccan Army of Liberation attacked the territory between November 1957 and July 1958. The attacks began on November 23, 1957, beginning the War of Ifni. However, the city was supplied by sea and air and protected by outposts. Initially, a good part of the military personnel were indigenous, especially those included in the Ifni Group of Shooters and in the Territorial Police. They were disarmed, demobilized, and promptly replaced. Except for a frustrated plan by the Moroccan irregular forces to eliminate the Spanish officers, the initial minor incidents and an attack, Sidi Ifni was not directly affected by the military events. These were developed in the interior of the territory. On the Spanish side, it was finally decided to establish a defensive perimeter that is denser and more difficult to infiltrate and, furthermore, easier to sustain and supply, near the city of Sidi Ifni (between 8 and 10 km from the city center, according to the zone) leaving most of arid territory that would have been much more costly to defend without appreciable advantage. Those defensive positions, quite numerous, and the dirt tracks that connect them, are still perfectly visible.

After the Ifni War, most of the territory became part of Morocco by the Treaty of Angra de Cintra. In 1958, the colony was declared a Spanish overseas province in order to forestall United Nations criticism of continued colonisation.

A fundamental aspect of Spanish political management in the area was the recognition and respect for the customs and traditions of the Baamarani population, as well as their religious beliefs. For example, Spain provided the means for the construction of mosques and for the Koranic education of Muslim schoolchildren. The prohibition of any kind of Christian religious proselytism was a perfectly known and respected principle.

On June 30, 1969, the Spanish government formally ceded what it kept from Ifni to Morocco, by virtue of the Retrocession Treaty signed in Fez on January 4 and ratified 22 April 1969, thus making the retrocession effective. After that, a difficult process of adaptation began, aggravated by an acute economic crisis and the imposition of the French-speaking administration.

Postage stamps
Spain began issuing postage stamps for Ifni in 1941, initially overprinting Spanish stamps with "TERRITORIO DE IFNI", then issuing new designs in 1943. Issues followed at the rate of about ten per year with the last on 23 November 1968. Most are commonly available and are more often seen unused than used.

title: Ifni


text:
Andrew Wells

Andrew Wells is a fictional character in the television series Buffy the Vampire Slayer and Angel, played by Tom Lenk. The character also appears in Buffy the Vampire Slayer Season Eight, the canonical continuation of the series.

Character history
Andrew Wells is the younger brother of Tucker Wells, who summoned hellhounds to attack the Prom in the Season Three episode "The Prom". Andrew himself has skills in demon-summoning and animal control, although these were never used after Season Six; in the Buffy finale "Chosen" he credits his brother with having given him the courage to develop this talent.

At some point during Buffy's senior year in high school, he summoned "flying demon monkeys" to attack Sunnydale High's production of Romeo and Juliet, apparently for no other reason than to amuse himself. Years after the fact, both Jonathan (Danny Strong) and Warren (Adam Busch) recall the incident with amusement; since Warren, Buffy's contemporary, is known to have spent only his senior year at Sunnydale High (he attended the prom to which Tucker sent the hellhounds), his memory of the occasion proves that it occurred during his senior year, which was also Buffy's. The Scooby Gang have no memory of this whatsoever; viewers are left with the impression that the attack ranks among any number of less-memorable supernatural incidents which plagued Sunnydale. They also have no recollection of who Andrew is, until he informs them of his relation to Tucker. This becomes a running joke, as from then on, he is often referred to as "the other guy," "Tucker's brother," and so on.

The Trio
Andrew was introduced in season 6 as part of The Trio, a group of nerds who thought of themselves as supervillains. This group included Jonathan, an acquaintance of Buffy and her friends, and Warren, a misogynist with delusions of grandeur. The Trio attempted a number of crimes that were usually thwarted by Buffy. Their crimes were mainly harmless until Warren killed his ex-girlfriend Katrina. Buffy defeated them one more time during a robbery attempt, with Warren escaping but Andrew and Jonathan getting caught. Warren took his revenge on Buffy by shooting her, accidentally killing Willow's girlfriend, Tara, in the process. In her grief, Willow killed Warren and attempted to kill Andrew and Jonathan. Buffy broke Andrew and Jonathan out of jail to keep them out of Willow's grasp. The duo escaped to Mexico before they could be brought back to jail.

Andrew's Return
While in Mexico, Andrew was visited by what he believed was Warren's ghost but was actually an ancient entity called the First Evil. Andrew killed Jonathan under the influence of the First Evil and was eventually captured by Buffy and her friends. He was resentful of them but eventually showed remorse for his actions, especially killing Jonathan, and joined them in their fight after the First Evil. He survived the final battle.

Sexuality
Andrew is occasionally hinted to be gay in the series. However, in the Angel episode "The Girl in Question", Andrew is shown leaving for the opera with two attractive women, commenting that "people change". In January 2008, gay men's website AfterElton.com awarded Andrew the status as the tenth best gay or bisexual character in modern science fiction, despite commenting upon the textual ambiguity of Andrew's sexual orientation. This prompted creator Joss Whedon to more formally comment on Andrew's sexuality, on Whedonesque.com.

"'It has to be said: the Andrew scene in 'The Girl in Question' was a victim of me dropping the ball. I specifically said there should be a party of men AND women, all glamorous and Italian, waiting for Andrew. I wasn't there when it was shot, and didn't have the time/money/energy to change it after the fact, though it made me crazy. Andrew's sexuality is always on the cusp of self-awareness because Andrew is stunted emotionally and because it's hilarious.' [...] 'The 'people change' thing is a hold-over from the fact that the scene was originally written for Dawn (but Michelle turned us down). The idea was, there's little Dawn, then in the last scene there's hot grown-up Dawn going out on the town, a heavy visual support of people changing (since Spike and Angel always see her as older brothers do).'"

In November 2008, Tom Lenk came out as gay in The Advocate magazine. Joss Whedon was interviewed for the article, and revealed that it was decided that the character of Andrew was to be gay when they decided to cast Lenk in the role.

"'Tom has a bit of a fey thing going on in his persona that, you know, you can't really deny. When I first looked at his audition tape, I said 'OK, he, uh, he seems kinda gay. Do we want to make that decision [about the character]? There's no reason why he couldn't be, so, great, let's pick the funniest actor.' [...] The character became very charming in his complete lack of awareness about, among other things, his own sexuality.'"

Appearances
Andrew has been in 86 canonical Buffyverse appearances.

Andrew appeared in 26 episodes:
 * Buffy the Vampire Slayer :
 * Season 6 (2001–02): "Flooded", "Life Serial", "Smashed", "Gone", "Dead Things", "Normal Again", "Entropy", "Seeing Red", "Villains", "Two to Go", "Grave"
 * Season 7 (2002–03): "Conversations with Dead People", "Never Leave Me", "Bring on the Night", "Showtime", "Potential", "The Killer in Me", "First Date", "Get It Done", "Storyteller", "Lies My Parents Told Me", "Dirty Girls", "Empty Places", "Touched", "End of Days", "Chosen"

Andrew appeared in 58 issues of the canonical comic series:
 * Season 8 (2007–11): "The Long Way Home, Parts 2 & 3", "The Chain", "Wolves at the Gate, Parts 1-4", "Harmonic Divergence", "Predators and Prey", "Living Doll", "Retreat, Parts 1-5", "Turbulence", "Twilight, Parts 1-4", "Last Gleaming, Part 1"
 * Season 9 (2011–13): "Freefall, Parts 1 & 3", "Apart (of Me), Parts 1-3", "Welcome to the Team, Parts 2-4", "The Watcher", "The Core, Parts 1-5"
 * Season 10 (2014–16): "New Rules, Parts 1-5", "I Wish, Part 1", "Return to Sunnydale, Parts 1 & 2", "Love Dares You, Parts 1-3", "Old Demons, Parts 2 & 3", "In Pieces on the Ground, Parts 1, 3 & 4", "Own It, Parts 2-5"
 * Season 11 (2016): "In Time of Crisis"
 * Season 12 (2018): "The Reckoning", "The Finale"

Andrew appeared as a guest in 2 episodes:
 * Angel :
 * Season 5 (2003–04): "Damage", "The Girl in Question"

title: Andrew Wells


text:
Business rule

A business rule defines or constrains some aspect of a business. It may be expressed to specify an action to be taken when certain conditions are true or may be phrased so it can only resolve to either true or false. Business rules are intended to assert business structure or to control or influence the behavior of the business. Business rules describe the operations, definitions and constraints that apply to an organization. Business rules can apply to people, processes, corporate behavior and computing systems in an organization, and are put in place to help the organization achieve its goals. For example, a business rule might state that no credit check is to be performed on return customers. Other examples of business rules include requiring a rental agent to disallow a rental tenant if their credit rating is too low, or requiring company agents to use a list of preferred suppliers and supply schedules. While a business rule may be informal or even unwritten, documenting the rules clearly and making sure that they don't conflict is a valuable activity. When carefully managed, rules can be used to help the organization to better achieve goals, remove obstacles to market growth, reduce costly mistakes, improve communication, comply with legal requirements, and increase customer loyalty.

Introduction
Business rules tell an organization what it can do in detail, while strategy tells it how to focus the business at a macro level to optimize results. A strategy provides high-level direction about what an organization should do. Business rules provide detailed guidance about how a strategy can be translated to action.

Business rules exist for an organization whether or not they are ever written down, talked about or even part of the organization's consciousness. However it is a fairly common practice for organizations to gather business rules. This may happen in one of two ways.

Organizations may choose to proactively describe their business practices, producing a database of rules. While this activity may be beneficial, it may be expensive and time-consuming. For example, they might hire a consultant to comb through the organization to document and consolidate the various standards and methods currently in practice.

Gathering business rules is also called rules harvesting or business rule mining. The business analyst or consultant can extract the rules from IT documentation (like use cases, specifications or system code). They may also organize workshops and interviews with subject matter experts (commonly abbreviated as SMEs). Software technologies designed to capture business rules through analysis of legacy source code or of actual user behavior can accelerate the rule gathering processing.

More commonly, business rules are discovered and documented informally during the initial stages of a project. In this case, the collecting of the business rules is incidental. In addition, business projects, such as the launching of a new product or the re-engineering of a complex process, might lead to the definition of new business rules. This practice of incidental, or emergent, business rule gathering is vulnerable to the creation of inconsistent or even conflicting business rules within different organizational units, or within the same organizational unit over time. This inconsistency creates problems that can be difficult to find and fix.

Business rules approach
Allowing business rules to be documented during the course of business projects is less expensive and easier to accomplish than the first approach, but if the rules are not collected in a consistent manner, they are not valuable. In order to teach business people about the best ways to gather and document business rules, experts in business analysis have created the Business Rules Methodology. This methodology defines a process of capturing business rules in natural language, in a verifiable and understandable way. This process is not difficult to learn, can be performed in real-time, and empowers business stakeholders to manage their own business rules in a consistent manner.

Categories
According to the white paper by the Business Rules Group, a statement of a business rule falls into one of four categories: The most basic element of a business rule is the language used to express it. The very definition of a term is itself a business rule that describes how people think and talk about things. Thus, defining a term is establishing a category of business rule. Terms have traditionally been documented in a Glossary or as entities in a conceptual model.
 * Definitions of business terms

The nature or operating structure of an organization can be described in terms of the facts that relate terms to each other. To say that a customer can place an order is NOT a business rule, but a fact. Facts can be documented as natural language sentences or as relationships, attributes, and generalization structures in a graphical model.
 * Facts relating terms to each other

Every enterprise constrains behavior in some way, and this is closely related to constraints on what data may or may not be updated. To prevent a record from being made is, in many cases, to prevent an action from taking place.
 * Constraints (also called "action assertions")

Business rules (including laws of nature) define how knowledge in one form may be transformed into other knowledge, possibly in a different form.
 * Derivations

Real world applications and obstacles
Business rules are gathered in these situations: This lack of consistent approach is mostly due to the cost and effort required to maintain the list of rules.
 * 1) When dictated by law
 * 2) During the business analysis
 * 3) As an ephemeral aid to engineers.

While newer software tools are able to combine business rule management and execution, it is important to realize that these two ideas are distinct, and each provides value that is different from the other. Software packages automate business rules using business logic. The term business rule is sometimes used interchangeably with business logic; however the latter connotes an engineering practice and the former an intrinsic business practice. There is value in outlining an organization's business rules regardless of whether this information is used to automate its operations.

One of the pitfalls in trying to fill the gap between rules management and execution is trying to give business rules the syntax of logic, and merely describing logical constructs in a natural language. Translation for engines is easier, but business users will no longer be able to write down the rules.

Formal specification
Business rules can be expressed using modeling approaches such as Unified Modeling Language (UML), Z notation, Business Process Execution Language (BPEL), Business Process Modeling Notation (BPMN), Decision Model and Notation (DMN) or the Semantics of Business Vocabulary and Business Rules (SBVR).

Business rules
Business rules encoded in computer code in an operational program are known as business logic.

Similar to how business risks can be structured as:

If  Then

a business rule can be structured as:

When  Then  Otherwise

title: Business rule