title: Durango

text: Durango's economic heyday came in the 18th century, when mines such as Guanaceví, Cuencamé and San Juan del Río began to produce in 1720. The first major mine owner of the era was José del Campo Soberrón y Larrea, who built a palatial residence for himself in the city of Durango in 1776 and received the title of Count of the Valley of Suchil. Starting in the second half of the 18th century, more mines came online. The next major mine owner was Juan José Zambrano, whose mines in Guarizamay did not earn him a noble title but did give him political power in the area. He constructed the second major palatial residence of the city of Durango. However, Zambrano's activities were curtailed by the problems caused by the American Revolution and other wars disrupting commerce with England, leading to shortages of mercury, essential for the extraction of silver.


title: Durango

text: In 1778, the Spanish government opened up trade in more Pacific ports, including Mazatlan, which had an economic benefit to Durango. Not only did products from the area have an outlet, incoming merchandise destined for Chihuahua and Zacatecas passed through the area. This attracted business people including foreign ones from Germany, England, France and Spain who built large businesses here in the 19th century.


title: Durango

text: During its height, Durango City's religious and cultural culture rivaled that of continental Europe even being a center for Italian liturgical music despite its isolation. The Durango Cathedral has one of the larger collections of 18th-century cathedral music in the America, roughly comparable to those in Oaxaca and Bogotá, but smaller than that of Mexico City. Much of the work is that of José Bernardo Abella Grijalva and most shows Italian influence. The historic center of the city and a number of haciendas reflect its 18th-century colonial heritage.


title: Durango

text: During Mexico's War of Independence, Nuevo Vizcaya began to break up. The first divisions were the creation of the states of Chihuahua and Durango, with Santiago Baca Ortiz as the first governor of the state of Durango along with the separation of the Sinaloa province, which included Sonora and Arizona. The state of Coahuila was separated shortly thereafter. With the 1824 Constitution the states of Durango and Chihuahua were created. Mining was depressed at the time, and the governor negotiated with the English to explore deposits of iron on the Cerro de Mercado. The English constructed installations such as those in Piedras Azules (La Ferrería) to process iron ore. These required large quantities of charcoal, which led to mass deforestation in the area. This eventually made the plant unviable.


title: Durango

text: Public education was first established in the state in 1824. The first secular institute of higher education in the state was the Colegio Civil y la Academia de Juisprudencia founded in 1833.


title: Durango

text: The northeast of the state had problems industrializing mostly due to incursions by Apaches into Durango which began in 1832 and later Comanches. Attacks by Comanches remain a major problem until the 1850s, forcing haciendas and textile mills to build walls around them. Counter-attacks on the Comanches diminished their raids, but they did not stop completely until the 1880s.


title: Durango

text: The rise of the state's second economic and political center, the cities of Gómez Palacio and Lerdo began in the 19th century, when cotton began to be planted along the Nazcas River. This cotton production became important, with sales of the raw material to Mexico City and to European textile mills, especially in England. Large-scale production began in the mid-century, dominating the local economy by the 1870s. Textile production also began here, although shortly after this industry would shift to Torreon. Other textile mills were established in areas such as Tunal, Santiago Papasquiaro, Poanas and Peñon Blanco, but the lack of coal meant that power had to be provided by nearby rivers, which was not efficient enough. This and attacks during the Mexican Revolution brought the demise of the textile industry in the state. Many mills and cotton haciendas eventually wound up in the hands of American investors.


title: Durango

text: The civil war between liberals and conservatives had the state controlled by liberal forces in 1858, then by conservative ones from 1864 to 1866.


title: Durango

text: In the late 19th century, rail and telegraph lines reached the state and revitalized Gómez Palacio and Lerdo as industrial centers. The railroad connected the city of Durango with Mexico City and the US border, allowing for shipment of local goods, particularly those from mining, to national and foreign markets. Agriculture and livestock production increased with the end of Comanche insurgencies and the arrival of a train line in 1892 gave the city a new connection with the rest of Mexico. It directly connected the city with Piedras Negras, Coahuila allowing the export of iron ore to foundries in Monclova, where coal was abundant. In 1902, a branch of the railroad reached Tepehuanes, allowing for the exploitation of natural resources in the northwest of the state.


title: Durango

text: However, the city of Durango remained the political center of the state as well as the regional commercial center for agricultural and handcrafted products. Mayors of the city at this time concentrated on improving infrastructure, such as government buildings, hospitals, water supply lines and public streets. The population of the city grew during this time.


title: Durango

text: While the state received high amounts of investment leading to economic development in the late 19th and very early 20th centuries, the benefits were mostly to foreign enterprises, often given permission to operate on indigenous lands and other rural communities. By 1910, North Americans own just about the entire southwest Sierra Madre Occidental region of the state or 65% of the land of the entire state. These areas have the highest concentrations of mining and timber resources.


title: Durango

text: Durango was one of the areas active during the Mexican Revolution. The first uprising in the state occurred on November 19, 1910 in Gómez Palacio. Various revolutionary leaders were from here and/or used the state as a base of operations including Francisco Villa, Calixto Contreras, Severingo Cenceros, J. Agustín Castro and Oreste Pereyra, especially in the La Lagunera region. The Division del Norte had a base in the Hacienda de la Loma to unite forces in Durango and Chihuahua.


title: Durango

text: The economic effects on the state were profound. There was a mass exodus of foreigners and a loss of production in both haciendas and factories. On June 18, 1913, insurgents took the city of Durango, burning businesses here. The war led to economic depression that lasted for decades. After the war, there was a process of land redistribution that lasted several decades, but it did not affect the largest land holdings on the most productive of lands. After the Revolution, large land holdings were broken up into ejidos under governor Enrique R. Calderón, particularly in the Comarca Lagunera de Durango. During the same time the municipalities of Mapimí and Goméz Palacio were split off from the municipality of Tlahualilo.


title: Durango

text: Despite Durango's support during the Revolution, the new government had trouble controlling the state as late as the 1930s as it resisted federal modernization efforts. The questions of land reform and education were central to Durango's discontent during this time period. Between 1926 and 1936, militias were formed to participate in the Cristero War and other uprisings such as the Escobar Military Revolt in 1929. One major point of contention was the government's efforts to take the church out of secular life, especially education, which threatened centuries-old ways of life, especially for many farmers and villagers. These rebellions were strongest in the center and south of the state, including the capital of Victoria de Durango. Rebel activity in parts of Mezquital were such that secular teachers were withdrawn for a time.


title: Durango

text: In the mid-20th century, several institutions of higher education were established, including universities and institutes of technology. This included the establishment of the UJED at the former Jesuit college in the city of Durango.


title: Durango

text: The two newest municipalities were established in the latter 20th century. Vicente Guerrero was split from Suchil and the last, Nuevo Ideal, was created in 1989.


title: Durango

text: The destruction of Durango's city center during the Mexican Revolution led to development outside of it. The first neighborhood, Colonia Obrera, was established near the rail line just outside what was the city proper. It was the first of various neighborhoods to follow these lines. The population grew noticeably in the 1960s and 1970s mostly due to migration from rural areas, increasing urban sprawl to 1,058 hectares. One major factor of this growth was the droughts of this time on agricultural production as well as expectations of industrial development. About the same time, the city government started efforts to regulate this growth.


title: Durango

text: The growth of the cities has prompted projects in infrastructure, especially in transportation from the latter 20th century to the present. Industrial parks such as Durango and Gomez Palacio were established. The most recent projects have an eye towards connecting the state better to participate in the global economy. In the 20th century, the Pan American highway was built through here (known today as Highway 45). However, a later reconstruction of the highway shifted it east into Zacatecas. This meant that any industrial progress in the state happened in the northern city of Gomez Palacios, and not in the capital. In the 1980s, highways to Gomez Palacios and Ciudad Juarez were modernized, and a highway to Torreón and Monterrey was built. The InterOceanic Highway, which crosses the north of Mexico to connect the Gulf of Mexico to the Pacific Ocean is Highway 40. The most important leg of this highway for Durango is that which connects it from the capital to Mazatlán, Sinaloa. It cut the drive time between to two places to four hours, replacing a winding mountain road plagued by bandits for many decades. The centerpiece of this highway is the Baluarte Bridge, one of the highest suspension bridges in the world. Pride in this construction can be seen in the city of Durango, with a replica of the bridge found to the side of the Guadiana Park.


title: Durango

text: Durango has historically been an area associated with banditry and smuggling. Durango is part of the "golden triangle" of Mexico's drug trade. Most of the violence is due to turf battles between the Sinaloa and Gulf cartels. The 2000s were a particularly difficult time as this was during Felipe Calderon's efforts to combat the drug cartels and for a time Joaquin Guzman ("El Chapo") hid out in the state. Most of the violence was in relation to control over the drug routes here. Drug-related violence was a major problem, with hundreds of bodies found in clandestine graves, around the city of Durango in particular. The violence reached a peak here between 2009 and 2011. Highway robberies were also a particular problem, especially on the highway leading to Mazatlan, then considered the most dangerous in Mexico. A new toll highway was built and opened at the end of this period to combat this.


title: Atmosphere of Mars

text: The atmosphere of Mars is the layer of gases surrounding Mars. It is primarily composed of carbon dioxide (95%), molecular nitrogen (2.8%), and argon (2%). It also contains trace levels of water vapor, oxygen, carbon monoxide, hydrogen, and noble gases. The atmosphere of Mars is much thinner than Earth's. The average surface pressure is only about which is less than 1% of the Earth's value. The currently thin Martian atmosphere prohibits the existence of liquid water on the surface of Mars, but many studies suggest that the Martian atmosphere was much thicker in the past. The higher density during spring and fall is reduced by 25% during the winter when carbon dioxide partly freezes at the pole caps. The highest atmospheric density on Mars is equal to the density found above the Earth's surface and is ≈0.020 kg/m. The atmosphere of Mars has been losing mass to space since the planet's core slowed down, and the leakage of gases still continues today.


title: Atmosphere of Mars

text: The atmosphere of Mars is colder than Earth's. Owing to the larger distance from the Sun, Mars receives less solar energy and has a lower effective temperature, which is about . The average surface emission temperature of Mars is just , which is comparable to inland Antarctica. The weaker greenhouse effect in the Martian atmosphere (, versus on Earth) can be explained by the low abundance of other greenhouse gases. The daily range of temperature in the lower atmosphere is huge due to the low thermal inertia; it can range from to near near the surface in some regions. The temperature of the upper part of the Martian atmosphere is also significantly lower than Earth's because of the absence of stratospheric ozone and the radiative cooling effect of carbon dioxide at higher altitudes.


title: Atmosphere of Mars

text: Dust devils and dust storms are prevalent on Mars, which are sometimes observable by telescopes from Earth, and in 2018 even with the naked eye as a change in colour and brightness of the planet. Planet-encircling dust storms (global dust storms) occur on average every 5.5 Earth years (every 3 Martian years) on Mars and can threaten the operation of Mars rovers. However, the mechanism responsible for the development of large dust storms is still not well understood. It has been suggested to be loosely related to gravitational influence of both moons, somewhat similar to the creation of tides on Earth.


title: Atmosphere of Mars

text: The Martian atmosphere is an oxidizing atmosphere. The photochemical reactions in the atmosphere tend to oxidize the organic species and turn them into carbon dioxide or carbon monoxide. Although the most sensitive methane probe on the recently launched ExoMars Trace Gas Orbiter failed to find methane in the atmosphere over the whole of Mars, several previous missions and ground-based telescope detected unexpected levels of methane in the Martian atmosphere, which may even be a biosignature for life on Mars. However, the interpretation of the measurements is still highly controversial and lacks a scientific consensus.


title: Atmosphere of Mars

text: In 1784, German-born British astronomer William Herschel published an article about his observations of the Martian atmosphere in Philosophical Transactions and noted the occasional movement of a brighter region on Mars, which he attributed to clouds and vapors. In 1809, French astronomer Honoré Flaugergues wrote about his observation of "yellow clouds" on Mars, which are likely to be dust storm events. In 1864, William Rutter Dawes observed that "the ruddy tint of the planet does not arise from any peculiarity of its atmosphere; it seems to be fully proved by the fact that the redness is always deepest near the centre, where the atmosphere is thinnest." Spectroscopic observations in the 1860s and 1870s led many to think the atmosphere of Mars is similar to Earth's. In 1894, though, spectral analysis and other qualitative observations by William Wallace Campbell suggested Mars resembles the Moon, which has no appreciable atmosphere, in many respects. In 1926, photographic observations by William Hammond Wright at the Lick Observatory allowed Donald Howard Menzel to discover quantitative evidence of Mars's atmosphere.


title: Atmosphere of Mars

text: With an enhanced understanding of optical properties of atmospheric gases and advancement in spectrometer technology, scientists started to measure the composition of the Martian atmosphere in the mid-20th century. Lewis David Kaplan and his team detected the signals of water vapor and carbon dioxide in the spectrogram of Mars in 1964, as well as carbon monoxide in 1969. In 1965, the measurements made during Mariner 4's flyby confirmed that the Martian atmosphere is constituted mostly of carbon dioxide, and the surface pressure is about 400 to 700 Pa. After the composition of the Martian atmosphere was known, astrobiological research began on Earth to determine the viability of life on Mars. Containers that simulated environmental conditions on Mars, called "Mars jars", were developed for this purpose.


title: Atmosphere of Mars

text: In 1976, two landers of the Viking program provided the first ever in-situ measurements of the composition of the Martian atmosphere. Another objective of the mission included investigations for evidence of past or present life on Mars (see Viking lander biological experiments). Since then, many orbiters and landers have been sent to Mars to measure different properties of the Martian atmosphere, such as concentration of trace gases and isotopic ratios. In addition, telescopic observations and analysis of Martian meteorites provide independent sources of information to verify the findings. The imageries and measurements made by these spacecraft greatly improve our understanding of the atmospheric processes outside Earth. The rover "Curiosity" and the lander "InSight" are still operating on the surface of Mars to carry out experiments and report the local daily weather. The rover "Perseverance" and helicopter "Ingenuity", which formed the Mars 2020 program, landed in February 2021. The rover "Rosalind Franklin" is scheduled to launch in 2022.


title: Atmosphere of Mars

text: CO is the main component of the Martian atmosphere. It has a mean volume ratio of 94.9%. In winter polar regions, the surface temperature can be lower than the frost point of CO CO gas in the atmosphere can condense on the surface to form 1–2 m thick solid dry ice. In summer, the polar dry ice cap can undergo sublimation and release the CO back to the atmosphere. As a result, significant annual variability in atmospheric pressure (≈25%) and atmospheric composition can be observed on Mars. The condensation process can be approximated by the Clausius–Clapeyron relation for CO.


title: Atmosphere of Mars

text: Despite the high concentration of CO in the Martian atmosphere, the greenhouse effect is relatively weak on Mars (about 5 °C) because of the low concentration of water vapor and low atmospheric pressure. While water vapor in Earth's atmosphere has the largest contribution to greenhouse effect on modern Earth, it is present in only very low concentration in the Martian atmosphere. Moreover, under low atmospheric pressure, greenhouse gases cannot absorb infrared radiation effectively because the pressure-broadening effect is weak.


title: Atmosphere of Mars

text: In the presence of solar UV radiation ("hν", photons with wavelength shorter than 225 nm), CO in the Martian atmosphere can be photolyzed via the following reaction:


title: Atmosphere of Mars

text: If there is no chemical production of CO, all the CO in the current Martian atmosphere would be removed by photolysis in about 3,500 years. The hydroxyl radicals (OH) produced from the photolysis of water vapor, together with the other odd hydrogen species (e.g. H, HO), can convert carbon monoxide (CO) back to CO. The reaction cycle can be described as:


title: Atmosphere of Mars

text: Mixing also plays a role in regenerating CO by bringing the O, CO, and O in the upper atmosphere downward. The balance between photolysis and redox production keeps the average concentration of CO stable in the modern Martian atmosphere.


title: Atmosphere of Mars

text: CO ice clouds can form in winter polar regions and at very high altitudes (>50 km) in tropical regions, where the air temperature is lower than the frost point of CO.


title: Atmosphere of Mars

text: N is the second most abundant gas in the Martian atmosphere. It has a mean volume ratio of 2.6%. Various measurements showed that the Martian atmosphere is enriched in N. The enrichment of heavy isotopes of nitrogen is possibly caused by mass-selective escape processes.


title: Atmosphere of Mars

text: Argon is the third most abundant gas in the Martian atmosphere. It has a mean volume ratio of 1.9%. In terms of stable isotopes, Mars is enriched in Ar relative to Ar, which can be attributed to hydrodynamic escape.


title: Atmosphere of Mars

text: One of Argon's isotopes, Ar, is produced from the radioactive decay of K. In contrast, Ar is primordial: It was present in the atmosphere after the formation of Mars. Observations indicate that Mars is enriched in Ar relative to Ar, which cannot be attributed to mass-selective loss processes. A possible explanation for the enrichment is that a significant amount of primordial atmosphere, including Ar, was lost by impact erosion in the early history of Mars, while Ar was emitted to the atmosphere after the impact.


title: Atmosphere of Mars

text: The estimated mean volume ratio of molecular oxygen (O) in the Martian atmosphere is 0.174%. It is one of the products of the photolysis of CO, water vapor, and ozone (O). It can react with atomic oxygen (O) to re-form ozone (O). In 2010, the Herschel Space Observatory detected molecular oxygen in the Martian atmosphere.


title: Atmosphere of Mars

text: Atomic oxygen is produced by photolysis of CO in the upper atmosphere and can escape the atmosphere via dissociative recombination or ion pickup. In early 2016, Stratospheric Observatory for Infrared Astronomy (SOFIA) detected atomic oxygen in the atmosphere of Mars, which has not been found since the Viking and Mariner mission in the 1970s.


title: Atmosphere of Mars

text: In 2019, NASA scientists working on the Curiosity rover mission, who have been taking measurements of the gas, discovered that the amount of oxygen in the Martian atmosphere rose by 30% in spring and summer.


title: Atmosphere of Mars

text: Similar to stratospheric ozone in Earth's atmosphere, the ozone present in the Martian atmosphere can be destroyed by catalytic cycles involving odd hydrogen species:


title: Atmosphere of Mars

text: Since water is an important source of these odd hydrogen species, higher abundance of ozone is usually observed in the regions with lower water vapor content. Measurements showed that the total column of ozone can reach 2–30 μm-atm around the poles in winter and spring, where the air is cold and has low water saturation ratio. The actual reactions between ozone and odd hydrogen species may be further complicated by the heterogeneous reactions that take place in water-ice clouds.


title: Atmosphere of Mars

text: It is thought that the vertical distribution and seasonality of ozone in the Martian atmosphere is driven by the complex interactions between chemistry and transport of oxygen-rich air from sunlit latitudes to the poles. The UV/IR spectrometer on "Mars Express" (SPICAM) has shown the presence of two distinct ozone layers at low-to-mid latitudes. These comprise a persistent, near-surface layer below an altitude of , a separate layer that is only present in northern spring and summer with an altitude varying from 30 to 60 km, and another separate layer that exists 40–60 km above the southern pole in winter, with no counterpart above the Mars's north pole. This third ozone layer shows an abrupt decrease in elevation between 75 and 50 degrees south. SPICAM detected a gradual increase in ozone concentration at until midwinter, after which it slowly decreased to very low concentrations, with no layer detectable above .


title: Atmosphere of Mars

text: Water vapor is a trace gas in the Martian atmosphere and has huge spatial, diurnal and seasonal variability. Measurements made by Viking orbiter in the late 1970s suggested that the entire global total mass of water vapor is equivalent to about 1 to 2 km of ice. More recent measurements by "Mars Express" orbiter showed that the globally annually-averaged column abundance of water vapor is about 10-20 precipitable microns (pr. μm). Maximum abundance of water vapor (50-70 pr. μm) is found in the northern polar regions in early summer due to the sublimation of water ice in the polar cap.


title: Atmosphere of Mars

text: Unlike in Earth's atmosphere, liquid-water clouds cannot exist in the Martian atmosphere; this is because of the low atmospheric pressure. Cirrus-like water-ice clouds have been observed by the cameras on "Opportunity" rover and "Phoenix" lander. Measurements made by the "Phoenix" lander showed that water-ice clouds can form at the top of the planetary boundary layer at night and precipitate back to the surface as ice crystals in the northern polar region.


title: Atmosphere of Mars

text: Under sufficiently strong wind (> 30 ms), dust particles can be mobilized and lifted from the surface to the atmosphere. Some of the dust particles can be suspended in the atmosphere and travel by circulation before falling back to the ground. Dust particles can attenuate solar radiation and interact with infrared radiation, which can lead to a significant radiative effect on Mars. Orbiter measurements suggest that the globally-averaged dust optical depth has a background level of 0.15 and peaks in the perihelion season (southern spring and summer). The local abundance of dust varies greatly by seasons and years. During global dust events, Mars surface assets can observe optical depth that is over 4. Surface measurements also showed the effective radius of dust particles ranges from 0.6 μm to 2 μm and has considerable seasonality.


title: Atmosphere of Mars

text: Dust has an uneven vertical distribution on Mars. Apart from the planetary boundary layer, sounding data showed that there are other peaks of dust mixing ratio at the higher altitude (e.g. 15–30 km above the surface).


title: Atmosphere of Mars

text: As a volcanic and biogenic species, methane is of interest to geologists and astrobiologists. However, methane is chemically unstable in an oxidizing atmosphere with UV radiation. The lifetime of methane in the Martian atmosphere is about 400 years. The detection of methane in a planetary atmosphere may indicate the presence of recent geological activities or living organisms. Since 2004, trace amounts of methane (range from 60 ppb to under detection limit (< 0.05 ppb)) have been reported in various missions and observational studies. The source of methane on Mars and the explanation for the enormous discrepancy in the observed methane concentrations are still under active debate.


title: Atmosphere of Mars

text: Sulfur dioxide (SO) in the atmosphere would be an indicator of current volcanic activity. It has become especially interesting due to the long-standing controversy of methane on Mars. If volcanoes have been active in recent Martian history, it would be expected to find SO together with methane in the current Martian atmosphere. No SO has been detected in the atmosphere, with a sensitivity upper limit set at 0.2 ppb. However, a team led by scientists at NASA Goddard Space Flight Center reported detection of SO in Rocknest soil samples analyzed by the "Curiosity" rover in March 2013.


title: Atmosphere of Mars

text: Carbon monoxide (CO) is produced by the photolysis of CO and quickly reacts with the oxidants in the Martian atmosphere to re-form CO. The estimated mean volume ratio of CO in the Martian atmosphere is 0.0747%.


title: Atmosphere of Mars

text: Noble gases, other than helium and argon, are present at trace levels (≈10 - 0.01 ppmv) in the Martian atmosphere. The concentration of helium, neon, krypton and xenon in the Martian atmosphere has been measured by different missions. The isotopic ratios of noble gases reveal information about the early geological activities on Mars and the evolution of its atmosphere.


title: Atmosphere of Mars

text: Molecular hydrogen (H) is produced by the reaction between odd hydrogen species in the middle atmosphere. It can be delivered to the upper atmosphere by mixing or diffusion, decompose to atomic hydrogen (H) by solar radiation and escape the Martian atmosphere. Photochemical modeling estimated that the mixing ratio of H in the lower atmosphere is about 15 ±5 ppmv.


title: Atmosphere of Mars

text: The vertical temperature structure of the Martian atmosphere differs from Earth's atmosphere in many ways. Information about the vertical structure is usually inferred by using the observations from thermal infrared soundings, radio occultation, aerobraking, landers' entry profiles. Mars's atmosphere can be classified into three layers according to the average temperature profile:


title: Atmosphere of Mars

text: Mars does not have a persistent stratosphere due to the lack of shortwave-absorbing species in its middle atmosphere (e.g. stratospheric ozone in Earth's atmosphere and organic haze in Jupiter's atmosphere) for creating a temperature inversion. However, a seasonal ozone layer and a strong temperature inversion in the middle atmosphere have been observed over the Martian south pole. The altitude of the turbopause of Mars varies greatly from 60 to 140 km, and the variability is driven by the CO density in the lower thermosphere. Mars also has a complicated ionosphere that interacts with the solar wind particles, extreme UV radiation and X-rays from Sun, and the magnetic field of its crust. The exosphere of Mars starts at about 230 km and gradually merges with interplanetary space.


title: Atmosphere of Mars

text: Dust devils are common on Mars. Like their counterparts on Earth, dust devils form when the convective vortices driven by strong surface heating are loaded with dust particles. Dust devils on Mars usually have a diameter of tens of meter and height of several kilometers, which are much taller than the ones observed on Earth. Study of dust devils' tracks showed that most of Martian dust devils occur at around 60°N and 60°S in spring and summer. They lift about 2.3 × 10 kg of dust from land surface to atmosphere annually, which is comparable to the contribution from local and regional dust storms.


title: Atmosphere of Mars

text: Local and regional dust storms are not rare on Mars. Local storms have a size of about 10 km and occurrence of about 2000 events per Martian year, while regional storms of 10 km large are observed frequently in southern spring and summer. Near the polar cap, dust storms sometimes can be generated by frontal activities and extratropical cyclones.


title: Atmosphere of Mars

text: Global dust storms (area > 10 km ) occur on average once every 3 Martian years. Observations showed that larger dust storms are usually the result of merging smaller dust storms, but the growth mechanism of the storm and the role of atmospheric feedbacks are still not well understood. Although it is thought that Martian dust can be entrained into the atmosphere by processes similar to Earth's (e.g. saltation), the actual mechanisms are yet to be verified, and electrostatic or magnetic forces may also play in modulating dust emission. Researchers reported that the largest single source of dust on Mars comes from the Medusae Fossae Formation.


title: Atmosphere of Mars

text: On 1 June 2018, NASA scientists detected of a dust storm (see ) on Mars which resulted in the end of the solar-powered "Opportunity" rover's mission since the dust blocked the sunlight (see ) needed to operate. By 12 June, the storm was the most extensive recorded at the surface of the planet, and spanned an area about the size of North America and Russia combined (about a quarter of the planet). By 13 June, "Opportunity" rover began experiencing serious communication problems due to the dust storm.


title: Atmosphere of Mars

text: Solar heating on the day side and radiative cooling on the night side of a planet can induce pressure difference. Thermal tides, which are the wind circulation and waves driven by such a daily-varying pressure field, can explain a lot of variability of the Martian atmosphere. Compared to Earth's atmosphere, thermal tides have a larger influence on the Martian atmosphere because of the stronger diurnal temperature contrast. The surface pressure measured by Mars rovers showed clear signals of thermal tides, although the variation also depends on the shape of the planet's surface and the amount of suspended dust in the atmosphere. The atmospheric waves can also travel vertically and affect the temperature and water-ice content in the middle atmosphere of Mars.


title: Atmosphere of Mars

text: On Earth, mountain ranges sometimes force an air mass to rise and cool down. As a result, water vapor becomes saturated and clouds are formed during the lifting process. On Mars, orbiters have observed a seasonally recurrent formation of huge water-ice clouds around the downwind side of the 20 km-high volcanoes Arsia Mons, which is likely caused by the same mechanism.


title: Atmosphere of Mars

text: On Mars, the near-surface wind is not only emitting dust but also modifying the geomorphology of Mars over long time scales. Although it was thought that the atmosphere of Mars is too thin for mobilizing the sandy features, observations made by HiRSE showed that the migration of dunes is not rare on Mars. The global average migration rate of dunes (2 – 120 m tall) is about 0.5 meter per year. Atmospheric circulation models suggested repeated cycles of wind erosion and dust deposition can lead, possibly, to a net transport of soil materials from the lowlands to the uplands on geological timescales.


title: Atmosphere of Mars

text: In April 2022, scientists reported, for the first time, studies of sound waves on Mars. These studies were based on measurements by instruments on the "Perseverance" rover. The scientists found that the speed of sound is slower in the Martian atmosphere, 100 times thinner than the terrestrial atmosphere, than the atmosphere on Earth; the speed of sound on Mars, within the audible bandwidth between 20 Hz - 20 kHz, varies depending on pitch, seemingly due to the low pressure and thermal turbulence of Martian surface air; and, as a result of these unique Martian conditions, sound is much quieter, and live music would be more variable, than on Earth.


title: Atmosphere of Mars

text: The mass and composition of the Martian atmosphere are thought to have changed over the course of the planet's lifetime. A thicker, warmer and wetter atmosphere is required to explain several apparent features in the earlier history of Mars, such as the existence of liquid water bodies. Observations of the Martian upper atmosphere, measurements of isotopic composition and analyses of Martian meteorites, provide evidence of the long-term changes of the atmosphere and constraints for the relative importance of different processes.


title: Atmosphere of Mars

text: In general, the gases found on modern Mars are depleted in lighter stable isotopes, indicating the Martian atmosphere has changed by some mass-selected processes over its history. Scientists often rely on these measurements of isotope composition to reconstruct conditions of the Martian atmosphere in the past.


title: Atmosphere of Mars

text: While Mars and Earth have similar C / C and O / O ratios, N is much more depleted in the Martian atmosphere. It is thought that the photochemical escape processes are responsible for the isotopic fractionation and has caused a significant loss of nitrogen on geological timescales. Estimates suggest that the initial partial pressure of N may have been up to 30 hPa.


title: Atmosphere of Mars

text: Hydrodynamic escape in the early history of Mars may explain the isotopic fractionation of argon and xenon. On modern Mars, the atmosphere is not leaking these two noble gases to outer space owing to their heavier mass. However, the higher abundance of hydrogen in the Martian atmosphere and the high fluxes of extreme UV from the young Sun, together could have driven a hydrodynamic outflow and dragged away these heavy gases. Hydrodynamic escape also contributed to the loss of carbon, and models suggest that it is possible to lose of CO by hydrodynamic escape in one to ten million years under much stronger solar extreme UV on Mars. Meanwhile, more recent observations made by the MAVEN orbiter suggested that sputtering escape is very important for the escape of heavy gases on the nightside of Mars and could have contributed to 65% loss of argon in the history of Mars.


title: Atmosphere of Mars

text: The Martian atmosphere is particularly prone to impact erosion owing to the low escape velocity of Mars. An early computer model suggested that Mars could have lost 99% of its initial atmosphere by the end of late heavy bombardment period based on a hypothetical bombardment flux estimated from lunar crater density. In terms of relative abundance of carbon, the ratio on Mars is only 10% of that on Earth and Venus. Assuming the three rocky planets have the same initial volatile inventory, then this low ratio implies the mass of CO in the early Martian atmosphere should have been ten times higher than the present value. The huge enrichment of radiogenic Ar over primordial Ar is also consistent with the impact erosion theory.


title: Atmosphere of Mars

text: One of the ways to estimate the amount of water lost by hydrogen escape in the upper atmosphere is to examine the enrichment of deuterium over hydrogen. Isotope-based studies estimate that 12 m to over 30 m global equivalent layer of water has been lost to space via hydrogen escape in Mars' history. It is noted that atmospheric-escape-based approach only provides the lower limit for the estimated early water inventory.


title: Atmosphere of Mars

text: To explain the coexistence of liquid water and faint young Sun during early Mars' history, a much stronger greenhouse effect must have occurred in the Martian atmosphere to warm the surface up above freezing point of water. Carl Sagan first proposed that a 1 bar H atmosphere can produce enough warming for Mars. The hydrogen can be produced by the vigorous outgassing from a highly reduced early Martian mantle and the presence of CO and water vapor can lower the required abundance of H to generate such a greenhouse effect. Nevertheless, photochemical modeling showed that maintaining an atmosphere with this high level of H is difficult. SO has also been one of the proposed effective greenhouse gases in the early history of Mars. However, other studies suggested that high solubility of SO, efficient formation of HSO aerosol and surface deposition prohibit the long-term build-up of SO in the Martian atmosphere, and hence reduce the potential warming effect of SO.


title: Atmosphere of Mars

text: Despite the lower gravity, Jeans escape is not efficient in the modern Martian atmosphere due to the relatively low temperature at the exobase (≈200 K at 200 km altitude). It can only explain the escape of hydrogen from Mars. Other non-thermal processes are needed to explain the observed escape of oxygen, carbon and nitrogen.


title: Atmosphere of Mars

text: Molecular hydrogen (H) is produced from the dissociation of HO or other hydrogen-containing compounds in the lower atmosphere and diffuses to the exosphere. The exospheric H then decomposes into hydrogen atoms, and the atoms that have sufficient thermal energy can escape from the gravitation of Mars (Jeans escape). The escape of atomic hydrogen is evident from the UV spectrometers on different orbiters. While most studies suggested that the escape of hydrogen is close to diffusion-limited on Mars, more recent studies suggest that the escape rate is modulated by dust storms and has a large seasonality. The estimated escape flux of hydrogen range from 10 cm s to 10 cm s.


title: Atmosphere of Mars

text: An ion and an electron can recombine and produce electronic-neutral products. The products gain extra kinetic energy due to the Coulomb attraction between ions and electrons. This process is called dissociative recombination. Dissociative recombination can produce carbon atoms that travel faster than the escape velocity of Mars, and those moving upward can then escape the Martian atmosphere:


title: Atmosphere of Mars

text: Other potentially important mechanisms include the sputtering escape of CO and collision of carbon with fast oxygen atoms. The estimated overall escape flux is about 0.6 × 10 cm s to 2.2 × 10 cm s and depends heavily on solar activity.


title: Atmosphere of Mars

text: Like carbon, dissociative recombination of N is important for the nitrogen escape on Mars. In addition, other photochemical escape mechanism also play an important role:


title: Atmosphere of Mars

text: Nitrogen escape rate is very sensitive to the mass of the atom and solar activity. The overall estimated escape rate of N is 4.8 × 10 cm s.


title: Atmosphere of Mars

text: Dissociative recombination of CO and O (produced from CO reaction as well) can generate the oxygen atoms that travel fast enough to escape:


title: Atmosphere of Mars

text: However, the observations showed that there are not enough fast oxygen atoms the Martian exosphere as predicted by the dissociative recombination mechanism. Model estimations of oxygen escape rate suggested it can be over 10 times lower than the hydrogen escape rate. Ion pick and sputtering have been suggested as the alternative mechanisms for the oxygen escape, but this model suggests that they are less important than dissociative recombination at present.


title: Atmosphere of Mars

text: Methane (CH) is chemically unstable in the current oxidizing atmosphere of Mars. It would quickly break down due to ultraviolet radiation from the Sun and chemical reactions with other gases. Therefore, a persistent presence of methane in the atmosphere may imply the existence of a source to continually replenish the gas.


title: Atmosphere of Mars

text: The ESA-Roscomos Trace Gas Orbiter, which has made the most sensitive measurements of methane in Mars' atmosphere with over 100 global soundings, has found no methane to a detection limit of 0.05 parts per billion (ppb). However, there have been other reports of detection of methane by ground-based telescopes and Curiosity rover. Trace amounts of methane, at the level of several ppb, were first reported in Mars's atmosphere by a team at the NASA Goddard Space Flight Center in 2003. Large differences in the abundances were measured between observations taken in 2003 and 2006, which suggested that the methane was locally concentrated and probably seasonal.


title: Atmosphere of Mars

text: In 2014, NASA reported that the "Curiosity" rover detected a tenfold increase ('spike') in methane in the atmosphere around it in late 2013 and early 2014. Four measurements taken over two months in this period averaged 7.2 ppb, implying that Mars is episodically producing or releasing methane from an unknown source. Before and after that, readings averaged around one-tenth that level. On 7 June 2018, NASA announced a cyclical seasonal variation in the background level of atmospheric methane.


title: Atmosphere of Mars

text: The principal candidates for the origin of Mars' methane include non-biological processes such as water-rock reactions, radiolysis of water, and pyrite formation, all of which produce H that could then generate methane and other hydrocarbons via Fischer–Tropsch synthesis with CO and CO. It has also been shown that methane could be produced by a process involving water, carbon dioxide, and the mineral olivine, which is known to be common on Mars. Living microorganisms, such as methanogens, are another possible source, but no evidence for the presence of such organisms has been found on Mars. There are some suspicions about the detection of methane, which suggests that it may instead be caused by the undocumented terrestrial contamination from the rovers or a misinterpretation of measurement raw data.


title: Atmosphere of Mars

text: In 2009, an Earth-based observational study reported detection of large-scale electric discharge events on Mars and proposed that they are related to lightning discharge in Martian dust storms. However, later observation studies showed that the result is not reproducible using the radar receiver on "Mars Express" and the Earth-based Allen Telescope Array. A laboratory study showed that the air pressure on Mars is not favorable for charging the dust grains, and thus it is difficult to generate lightning in Martian atmosphere.


title: Atmosphere of Mars

text: Super-rotation refers to the phenomenon that atmospheric mass has a higher angular velocity than the surface of the planet at the equator, which in principle cannot be driven by inviscid axisymmetric circulations. Assimilated data and general circulation model (GCM) simulation suggest that super-rotating jet can be found in Martian atmosphere during global dust storms, but it is much weaker than the ones observed on slow-rotating planets like Venus and Titan. GCM experiments showed that the thermal tides can play a role in inducing the super-rotating jet. Nevertheless, modeling super-rotation still remains as a challenging topic for planetary scientists.


title: Atmosphere of Mars

text: The atmosphere of Mars is a resource of known composition available at any landing site on Mars. It has been proposed that human exploration of Mars could use carbon dioxide (CO) from the Martian atmosphere to make methane (CH) and use it as rocket fuel for the return mission. Mission studies that propose using the atmosphere in this way include the Mars Direct proposal of Robert Zubrin and the NASA Design Reference Mission study. Two major chemical pathways for use of the carbon dioxide are the Sabatier reaction, converting atmospheric carbon dioxide along with additional hydrogen (H), to produce methane (CH) and oxygen (O), and electrolysis, using a zirconia solid oxide electrolyte to split the carbon dioxide into oxygen (O) and carbon monoxide (CO).


title: Atmosphere of Mars

text: In 2021, however, the NASA spaceship Perseverance was able to make oxygen on Mars. The process is complex and takes a lot of time to produce a small amount of oxygen.


title: Palmdale, California

text: Palmdale is a city in northern Los Angeles County in the U.S. state of California. The city lies in the Antelope Valley region of Southern California. The San Gabriel Mountains separate Palmdale from the Los Angeles Basin to the south.


title: Palmdale, California

text: On August 24, 1962, Palmdale became the first city in the Antelope Valley. Forty-seven years later, in November 2009, voters approved making it a charter city. Palmdale's population was 169,450 at the 2020 census, up from 152,750 at the 2010 census. Palmdale is the 32nd most populous city in California. Together with its immediate northern neighbor, the city of Lancaster, the Palmdale/Lancaster urban area had an estimated population of 513,547 as of 2013.


title: Palmdale, California

text: Palmdale was first inhabited by Native Americans. Populated by different cultures for an estimated 11,000 years, the Antelope Valley was a trade route for Native Americans traveling from Arizona and New Mexico to California's coast.


title: Palmdale, California

text: Spanish soldier Captain Pedro Fages explored the Antelope Valley in 1772. The opening of California to overland travel through the forbearing desert was due to Captain Juan Bautista de Anza and Father Francisco Garces, a Spanish padre. They led a colonizing expedition including 136 settlers across the Mojave Desert from Mexico to Monterey in 1773.


title: Palmdale, California

text: Later in 1776 while exploring the Valley, Garces with several Indian guides from the San Gabriel Mission recorded viewing the vast expanse of what was the El Tejon Rancheria (the Badger Ranch) of the Cuabajoy Indians. After the Shoshone Indians left the valley, immigrants from Spain and Mexico established large cattle ranches there. Then, in the late 1880s, the ranches were broken up into smaller homesteads by farmers from Germany, France and the state of Nebraska.


title: Palmdale, California

text: "Palmenthal", the first European settlement within the limits of Palmdale, was established as a village on April 20, 1886, by westward Lutheran travelers from the American Midwest, mostly of German and Swiss descent. According to area folklore, the travelers had been told they would know they were close to the ocean when they saw palm trees. They took the local Joshua trees for palms and named their settlement after them. ("Palmenthal" is German for "Palm Valley.") According to David L. Durham Joshua trees were sometimes called yucca palms at the time, which was the reason for the name. The village was officially established upon the arrival of a post office on June 17, 1888.


title: Palmdale, California

text: By the 1890s (soon after the last of the indigenous antelopes, which the valley was named after, had died), farming families continued to migrate to Palmenthal and nearby "Harold" to grow grain and fruit. However, most of these settlers were unfamiliar with farming in a desert climate, so when the drought years occurred, most abandoned their settlement.


title: Palmdale, California

text: By 1899, only one family was left in the original village. The rest of the settlers, including the post office, moved closer to the "Southern Pacific" railroad tracks. This new community was renamed Palmdale and was located where the present day civic center is. A railroad station was built along the tracks there. This railroad was operated by Southern Pacific and traveled between Los Angeles and San Francisco. The "Wells Fargo" stagecoach line that ran between San Francisco and New Orleans stopped there as well.


title: Palmdale, California

text: The only remaining pieces of evidence of the original settlements of Palmenthal and Harold are the old Palmdale Pioneer cemetery located on the northeast corner of Avenue S and 20th Street East, recently acquired and restored by the city as part of a future historical park, and the old schoolhouse now relocated to "McAdam Park".


title: Palmdale, California

text: As the population of Palmdale began to increase after relocation, water became scarce, until November 5, 1913 when the California – Los Angeles Aqueduct system was completed by William Mulholland, bringing water from the Owens Valley into Los Angeles County. During this period, crops of apples, pears and alfalfa became plentiful.


title: Palmdale, California

text: In 1915, Palmdale's first newspaper, the "Palmdale Post", was published. Today it is called the Antelope Valley Press.


title: Palmdale, California

text: In 1921, the first major motor vehicle link between Palmdale and Los Angeles was completed, Mint Canyon/Lancaster Road, later designated U.S. Route 6. Completion of this road caused the local agricultural industry to flourish and was the first major step towards defining the metropolis that exists today. Presently this road is known as Sierra Highway.


title: Palmdale, California

text: In 1924, the Little Rock Dam and the Harold Reservoir, present day Lake Palmdale, were constructed to assist the agricultural industry and have enough water to serve the growing communities.


title: Palmdale, California

text: Agriculture continued to be the foremost industry for Palmdale and its northern neighbor Lancaster until the outbreak of World War II. In 1933, the United States government established Muroc Air Base (from an original founder's name, Effie Corum, spelled backwards) six miles (10 km) north of Lancaster in Kern County, now known as Edwards Air Force Base.


title: Palmdale, California

text: They also bought Palmdale Airport in 1952 and established an aerospace development and testing facility called United States Air Force Plant 42. One year later, in 1953, Lockheed established a facility at the airport. After this point in time, the aerospace industry took over as the primary local source of employment. The city has been referred to as the "Aerospace Capital of America" because of its rich heritage in being the home of many of the aircraft used in the United States military.


title: Palmdale, California

text: In August 1956, an unpiloted out-of-control Navy drone flew over Palmdale while Air Force Interceptor aircraft tried to shoot it down with unguided rockets. Many rockets landed in and around the city, starting fires and damaging property.


title: Palmdale, California

text: In 1957, Palmdale's first high school, Palmdale High School, was established, making it easier for youths to not have to travel to Antelope Valley High School in nearby Lancaster.


title: Palmdale, California

text: In August 1962, the township of Palmdale officially became the "city" of Palmdale with the incorporation of of land around the present day civic center.


title: Palmdale, California

text: In 1964, the Antelope Valley Freeway, or State Highway 14, was completed as a link between Palmdale and Los Angeles. The freeway at this time ran all the way to present-day Technology Drive. It was at this time that talk about the future "Palmdale Intercontinental Airport" was seen as the way of the future. By 1965, the new city had annexed an additional of land and industry was thriving. Talk of the future commercial airport had many investors buying up large quantities of land.


title: Palmdale, California

text: By 1974, the Antelope Valley Freeway construction ended at the southern border of Mojave in Kern County. In 1977, Palmdale built its first municipal building, the Palmdale City Library. This was the same year that its northern neighbor Lancaster incorporated as a city. Since the 1920s, Lancaster had been the much larger and principal community of the Antelope Valley, as well as the rest of California's Mojave Desert.


title: Palmdale, California

text: The 1980s and 1990s were the decades that really started to define the two Antelope Valley cities. Affordable housing in the area caused a dramatic spike in the population. The city, like its northern neighbor Lancaster, became a bedroom community for those employed in Los Angeles. In 1980, Palmdale's population was 12,227.


title: Palmdale, California

text: Palmdale is located in Los Angeles County, and the urbanized centers of Palmdale and Los Angeles are separated by the San Gabriel mountain range, which is about wide. This range forms the southern edge of the Antelope Valley portion of the Mojave Desert. Palmdale is the second-most populous city in the Antelope Valley, and fifth overall in the Mojave Desert, after Las Vegas, Henderson, North Las Vegas, Nevada; and Lancaster. Palmdale is part of a twin-city complex with its northern neighbor Lancaster and together they are the principal cities within the Antelope Valley region and California's High Desert.


title: Palmdale, California

text: According to the United States Census Bureau the city has a total area of , of which, of it is land and of it is water (including man-made Lake Palmdale, the most visible and scenic part of the municipal water supply system). The total area is 0.24% water.


title: Palmdale, California

text: The city lies in proximity to the San Andreas Fault, making it prone to severe earthquakes. This fault cuts across the Antelope Valley Freeway just north of the Avenue S off-ramp; running westward along the old Butterfield Stage Line (now Elizabeth Lake Road) into Leona Valley.


title: Palmdale, California

text: Typical of the High Desert, Palmdale has an arid climate (Köppen climate classification "BWk"), and it is part of USDA Plant Hardiness Zone 8b. Winters are cool to mild, with daily normal minimum temperatures at or just below freezing from late November until late January, and the coolest month, December, having a normal mean temperature of . Summers are hot and nearly rainless, with July and August, tied for the hottest month, having a normal mean temperature of . On average, annually there are 52 mornings with a minimum at or below freezing, and 35 afternoons with a maximum at or above . The normal annual rainfall is , occurring on an average of only 27 days.


title: Palmdale, California

text: Record temperatures range from on January 13, 1963 to on August 5, 1990. The “rain year” from July 1940 to June 1941 had the highest annual precipitation on record, at , whilst the most precipitation in a calendar month was in December 1943 at , as well as the most in one calendar day on December 11, 1943, at ; conversely, the lowest annual precipitation was from July 2012 to June 2013.


title: Palmdale, California

text: Plants native to Palmdale are big berry manzanita, fremont cottonwood, California aster, White Sage, Giant wildrye, Deerbrush, California buckwheat, Black Sage, California Goldfields, Antelope Bitterbrush, Golden Yarrow, Desert Globemallow and more. Animals in the area are golden mantled ground squirrel, Beechey ground squirrel, red-tailed hawk, Cooper's hawk, Stellar's jay, leopard frog and rattlesnake. Coyotes are found throughout Palmdale. The California condor, a rare species of bird occupies Palmdale. Palmdale was a juniper berry processing area. California poppies are grown near Palmdale.


title: Palmdale, California

text: The 2010 United States Census reported that Palmdale had a population of 152,750. The population density was . The racial makeup of Palmdale was 74,901 (49.0%) White, (24.5% Non-Hispanic White), 22,677 (14.8%) African American, 1,316 (0.9%) Native American, 6,548 (4.3%) Asian (2.2% Filipino, 0.4% Indian, 0.4% Korean, 0.3% Chinese, 0.3% Vietnamese, 0.2% Japanese,


title: Palmdale, California

text: 0.07% Pakistani), 335 (0.2%) Pacific Islander, 38,773 (25.4%) from other races, and 8,200 (5.4%) from two or more races. There were 83,097 Hispanic or Latino residents (54.4%). 38.1% of Palmdale residents are of Mexican ancestry; 6.2% Salvadoran; and 2.4% of Guatemalan heritage and 0.79% Honduran, 0.76% Puerto Rican, 0.69% Nicaraguan, 0.50% Cuban, 0.47% Colombian and Argentinian 0.34%. Spanish is spoken by 36.4% of the population and Tagalog by 1.3%. The most common ancestries are German 5.2%, Irish 4.1%, English 2.9%, Italian 2.7%, French 1.1%, Polish 1.0%, Norwegian 0.7%, Scottish 0.6%, Dutch 0.6%, Russian 0.6%, Swedish 0.5%, Belizean 0.4%, Armenian 0.4% and Danish, Welsh and Greek 0.3%.


title: Palmdale, California

text: The Census reported that 152,551 people (99.9% of the population) lived in households, 158 (0.1%) lived in non-institutionalized group quarters, and 41 (0%) were institutionalized.


title: Palmdale, California

text: There were 42,952 households, out of which 23,345 (54.4%) had children under the age of 18 living in them, 24,199 (56.3%) were opposite-sex married couples living together, 7,821 (18.2%) had a female householder with no husband present, 3,318 (7.7%) had a male householder with no wife present. There were 2,998 (7.0%) unmarried opposite-sex partnerships, and 316 (0.7%) same-sex married couples or partnerships. 5,828 households (13.6%) were made up of individuals, and 1,880 (4.4%) had someone living alone who was 65 years of age or older. The average household size was 3.55. There were 35,338 families (82.3% of all households); the average family size was 3.87.


title: Palmdale, California

text: The age distribution of the population included 50,514 people (33.1%) under the age of 18, 17,089 people (11.2%) aged 18 to 24, 40,077 people (26.2%) aged 25 to 44, 34,963 people (22.9%) aged 45 to 64, and 10,107 people (6.6%) who were 65 years of age or older. The median age was 29.7 years. For every 100 females, there were 95.3 males. For every 100 females age 18 and over, there were 91.3 males.


title: Palmdale, California

text: There were 46,544 housing units at an average density of , of which 29,167 (67.9%) were owner-occupied, and 13,785 (32.1%) were occupied by renters. The homeowner vacancy rate was 3.2%; the rental vacancy rate was 9.4%. 102,444 people (67.1% of the population) lived in owner-occupied housing units and 50,107 people (32.8%) lived in rental housing units.


title: Palmdale, California

text: During 2009–2013, Palmdale had a median household income of $53,922, with 21.2% of the population living below the federal poverty line.


title: Palmdale, California

text: 26.30% are foreign born, 88.7% from Latin America. Most refugees in Palmdale came from Iran and Iraq.


title: Palmdale, California

text: El Salvador 15.8%, Philippines 6.4%, Guatemala 6.2%, Korea 1.7%, Nicaragua 1.6% , Honduras 1.6%, Vietnam 1.5%, Iran 1.1% and Colombia 1.1%.


title: Palmdale, California

text: Palmdale was mostly white up until the late 1970s. African Americans have moved to the city in significant numbers due to gentrification of Compton and South Los Angeles. Palmdale has a growing Latino and minority population.


title: Palmdale, California

text: Valley fever, a disease endemic to some desert areas of the United States in Arizona, California, Nevada, New Mexico, Texas, Utah, and northern Mexico is known to appear in Palmdale.


title: Palmdale, California

text: The Antelope Valley has the highest suicide rate in Los Angeles County. Palmdale residents are more at risk for depression. Palmdale is the fifth most stressful city in California.


title: Palmdale, California

text: African Americans living in Palmdale are more likely to have a lower life expectancy and shorter life.


title: Palmdale, California

text: In 2020, a 24 year old black man named Robert Fuller was found hung and committed suicide in Palmdale.


title: Palmdale, California

text: The most important industry for Palmdale is the aerospace industry. Other manufacturing companies have relocated to Palmdale seeking more affordable land, proximity to Palmdale Airport, and special tax breaks.


title: Palmdale, California

text: The special tax breaks granted for companies that relocate to Palmdale is due to the city having the Antelope Valley Enterprise Zone and the Palmdale Federal Foreign Trade Zone. These are special zoning areas within the city that are given various state and federal tax breaks and municipal grant incentives to relocate their business there. These zones were put in effect to help Palmdale, as well as nearby Lancaster, draw more jobs to the area so that they would be less dependent on the Los Angeles Basin and the San Fernando Valley area for employment. This will help relieve traffic congestion and pollution and stabilize the Antelope Valley economy on several industries. The local governments of the Antelope Valley seek to diversify their economies and not just depend on the aerospace industry as it is known for having "feast or famine" seasons.


title: Palmdale, California

text: Palmdale refers to itself with the nickname the "aerospace capital of the United States", and has been the site of research, development, final assembly, flight testing and/or servicing/modifications of the Space Shuttle, B-1 Lancer, X-15, B-2 Spirit, F-117 Nighthawk, F-35 Lightning II, SR-71 Blackbird, Lockheed L-1011 Tristar, and many other aircraft that have been used in the United States Air Force, NASA and air forces and airlines around the world. USAF Plant 42, where the aerospace projects occurred / occur is home to major operations of the following aerospace companies: Boeing, Lockheed Martin and its famed Skunk Works, and Northrop Grumman. The Los Angeles World Airports owns the former Boeing hangar (formerly North American Rockwell) at Plant 42 near LA/Palmdale Regional Airport which is one of the largest buildings in the world. The hangar was used for the set of the 2004 film "The Terminal", which featured an enormous replica of a JFK International Airport terminal. NASA's SOFIA program relocated its operation to this hangar at Site 9 from Edwards Air Force Base.


title: Palmdale, California

text: A number of world class corporations and manufacturing firms have made Palmdale home, helping to diversify the local economy. Delta Scientific, a world leader in high strength vehicle barrier systems, supplying protection for many federal, state and local buildings, and a prime supplier to the military and US State Department for embassies and other installations worldwide, and US Pole, a major manufacturer of street lighting poles, are major anchor tenants in the Fairway Business Park. The Palmdale Trade and Commerce Center is home to many other major manufacturing, industrial, corporate offices and other employers, as well as home to the Palmdale Auto Mall. A number of medical and related support offices are coming on-line to meet the needs of the new Palmdale Regional Medical Center. On July 8, 2009 Quallion LLC, which manufactures lithium ion cells and battery packs, announced plans to build a battery manufacturing plant in Palmdale if it won a government grant being offered by the U.S. Department of Energy.


title: Palmdale, California

text: Beginning in the 1960s, Palmdale was home to Don Babb's The Model A Ford Company, which became Classic Manufacturing and Supply, builder of exact reproduction and custom steel bodies and parts for hot rods and customs.


title: Palmdale, California

text: With an $890-million contract to build 175 light-rail cars for Metropolitan Transportation Authority that was behind schedule, Kinkisharyo, the El Segundo-based U.S. arm of Kinki Sharyo Co. Ltd. of Osaka announced in December 2014 that they would retrofit an existing space in Palmdale to build the P3010 series vehicles. A major shipment was needed for the Expo Line Phase II extension to Santa Monica and Gold Line Foothill Extension to Azusa which were scheduled to open in 2016. The balance of the 175 cars will be needed in the following years as the K Line and Downtown Connector open. Final assembly work has already occurred in hangar space the company leased in Palmdale from Los Angeles World Airports. The first car was delivered to Metro in October for testing before series production begins.


title: Palmdale, California

text: The Antelope Valley Mall is the retail shopping destination in the region, with a variety of dining choices on its restaurant row.


title: Palmdale, California

text: Onions are the most valued crop that grows in Palmdale. Some of Antelope Valley's onions were exported to Japan, Taiwan, Dubai and Australia. Other crops grown in Palmdale and the Antelope Valley are alfalfa, wheat, fruit, oats and barley.


title: Palmdale, California

text: Palmdale is a Charter City governed under the council / manager form of local government. Beginning with the November 2016 election, the City Council was subjected to districting, with councilmembers were selected from each of 4 districts. The mayor is elected at-large every two years for a two-year term. Every two years, two of the four district council members are elected to serve four-year terms. Palmdale does not have term limits for council and mayor.


title: Palmdale, California

text: The city also has an appointed Planning Commission divided into four separate districts. The Planning Commission was organized to help with the planning, zoning, and development of various city areas in different districts and to give the residents of those particular districts a greater voice in local land use decisions. There is also an appointed Board of Library Trustees, and Youth Council.


title: Palmdale, California

text: On November 3, 2009, local residents voted in favor of a measure to change Palmdale's general law city status to that of a Charter city. This allowed Palmdale to draft a city charter and constitution, enabling it to make more decisions at the local level without interference or rules from the state government.


title: Palmdale, California

text: The city provides a number of municipal services, including a Planning Department, Economic Development Department, Building and Safety Department, Public Works Department, Parks and Recreation Department, and Library Department. The city also operates the Palmdale Transportation Center which serves as the hub for public transit services including Metrolink trains, Antelope Valley Transit Authority, Amtrak California's Thruway Motorcoach and Greyhound. Palmdale was selected as a stop for the California High-Speed Rail System that will link northern and southern California. City officials have formed the Palmdale Airport Authority, as they pursue regional air service from a joint use facility at USAF Plant 42.


title: Palmdale, California

text: Recreation and cultural services include the Palmdale City Library, Legacy Commons, Larry Chimbole Cultural Center, Palmdale Playhouse and Art Gallery, Dry Town Water Park, Palmdale Amphitheater, Best of the West Softball Complex, Hammack Activity Center, Palmdale Oasis Park Recreation Center, Marie Kerr Park Recreation Center, Joe Davies Heritage Airpark at Palmdale Plant 42, and four swimming pools.


title: Palmdale, California

text: The city is policed by the Los Angeles County Sheriff's Department under a formal contract with the County of Los Angeles and has its municipal judicial system intertwined with the Los Angeles County Superior Court.


title: Palmdale, California

text: The Los Angeles County Sheriff's Department (LASD) operates the Palmdale Station in Palmdale. Palmdale has the largest Sheriff's Station in Los Angeles County. Palmdale's innovative Partners Against Crime (PAC) Program, a cooperative effort between law enforcement, landlords and community members, has successfully focused on quality of life issues and crime suppression, reducing the crime rate annually. Recently, the Partners for a Better Palmdale program was initiated by the City Council, to further engage residents, schools, community groups and law enforcement in improving community quality of life. The city pioneered the use of municipal Community Service Officers for low level incidents to free up Deputies for higher priority matters, and employ high-tech tools, such as Automated License Plate Recognition Systems on patrol cars, to increase officer productivity.


title: Palmdale, California

text: The city is served by the Los Angeles County Fire Department for its fire and paramedic services through the Consolidated Fire Protection District. Palmdale downtown Station #37 is one of the busiest fire stations in the United States. Two new fire stations went into service in late 2008 on the east and west sides of Palmdale.


title: Palmdale, California

text: Utility services within the city are provided by several public and private agencies. Water service is primarily provided by Palmdale Water District (separate public agency) and Los Angeles County Waterworks (part of the County Public Works); sewer service is provided by the County Sanitation Districts of Los Angeles County (separate public agency, with City Council members on district board); electrical service is provided by Southern California Edison; natural gas service is provided by Southern California Gas; cable television service is provided by Time Warner Cable; telephone service is provided by AT&T and Frontier; refuse pickup and disposal service is provided by Waste Management, Inc of the Antelope Valley under a franchise agreement with the city. The city successfully licensed and sold permits for a hybrid natural gas and steam turbine power facility and its operator is awaiting state approval of amendments to begin construction.


title: Palmdale, California

text: The Los Angeles County Department of Health Services operates the Antelope Valley Health Center in Lancaster, serving Palmdale.


title: Palmdale, California

text: In the Los Angeles County Board of Supervisors, Palmdale is in the 5th District, represented by Kathryn Barger.


title: Palmdale, California

text: According to the latest U.S. Census report released in September 2009, Palmdale has the longest average commute time in the United States at 41.5 minutes. This commute time exceeds that of even New York City. this is due to the majority of citizens commuting to nearby Santa Clarita and farther south to Los Angeles.


title: Palmdale, California

text: The LA/Palmdale Regional Airport/Air Force Plant 42 (PMD) has two runways, each over in length, although there is currently no commercial airline service at the airport. PMD's commercial terminal is owned and operated by Los Angeles World Airports (LAWA), a municipal department of the City of Los Angeles, on leased land from the U.S. Air Force. Airline service has been sporadic since commercial flights were first offered in 1971. Most recently, United Express/SkyWest Airlines flew between PMD and San Francisco from June 7, 2007, to December 6, 2008. The city of Palmdale formed the Palmdale Airport Authority to move forward to control the facilities and the lease with the USAF, to better develop regional air service in the High Desert.


title: Palmdale, California

text: NASA has consolidated its research, environmental and training aircraft, support services and facilities at the Dryden Aircraft Operations Facility in Palmdale. From the oversized runway and the massive hangar located at Air Force Plant 42 Site 9, NASA conducts worldwide environmental research with its ER-2 (a U-2 variant) and cutting edge deep space imaging with the 747-based SOFIA infrared telescope.


title: Palmdale, California

text: The Antelope Valley Freeway (SR 14) is the major north–south highway connecting Palmdale to Los Angeles and Mojave.


title: Palmdale, California

text: State Route 138 (SR 138) is the major east–west highway connecting Palmdale to the Inland Empire and Frazier Park.


title: Palmdale, California

text: State Route 18 (SR 18) heads eastward out of the Antelope Valley connecting it to Victorville and via I-15 the Barstow area. This road is commonly used as a route to Las Vegas, Nevada.


title: Palmdale, California

text: Caltrans only recently began upgrades to SR 138 (nicknamed "Blood Alley" due to the high rate of accidents that occur). Caltrans has had plans on the table for several years for SR 138 and SR 18 to create an east–west freeway between Palmdale and I-15. Due to State funding constraints, however, this expressway will probably not be completed. There has been discussion of creating the High Desert Corridor tollway in its place. Caltrans put the freeway project on hold in 2019. There is also a plan to continue the freeway from Palmdale along the southern foothills of the Antelope Valley to I-5 in Gorman.


title: Palmdale, California

text: State Route 48 (SR 48) is a planned east–west freeway connecting the Antelope Valley Freeway (SR 14) at Avenue D, the current segment terminus for the western SR 138 branch, to Interstate 5 in Gorman. This freeway is planned to come after SR 138 has its new southern realignment through Palmdale completed, and will follow the existing SR 138 right of way.


title: Palmdale, California

text: State Route 122 (SR 122) is a planned north–south freeway from eastern Palmdale, passing east of Edwards Air Force Base to SR 58 near California City.


title: Palmdale, California

text: State Route 249 (SR 249) is a planned north–south freeway from southern Palmdale through the San Gabriel Mountains to I-210 in La Cañada Flintridge, near Pasadena.


title: Palmdale, California

text: The street system in the Antelope Valley is set out in a grid. Unless otherwise named or curved around due to terrain, east–west roads are called avenues and north–south roads are called streets. The city is essentially on a perfect grid, and the traffic signals are coordinated by a central processing facility at the Civic Center.


title: Palmdale, California

text: East–west avenues are lettered mile-by-mile from north to south, starting with Avenue A on the Los Angeles-Kern County line. One mile south of Avenue A is Avenue B, and so on. Smaller roads between major avenues carry suffixes "-1" (nearest to the lettered avenue) through "-15" (nearest to the next lettered avenue). Some "-8" avenues can be major thoroughfares, for example, Avenue R-8 is halfway between Avenue R and Avenue S.


title: Palmdale, California

text: North–south streets are numbered with an "east" or "west" suffix with respect to their distances from Division Street. The number increases by 10 for each mile, so a mile east and west of Division Street lie "10th Street East" and "10th Street West" respectively. Some streets like 5th or 15th can also be major thoroughfares.


title: Palmdale, California

text: House addresses on east–west "avenues" are numbered according to the "streets". For example, "2001 East Palmdale Boulevard" is just east of 20th Street East, and "6066 West Avenue M-2" is just west of 60th Street West on Avenue M-2, which is 2/16 of a mile south of Avenue M.


title: Palmdale, California

text: On north–south streets, numbers are counted from downtown Los Angeles (thus increase from south to north), and while in the Antelope Valley, the difference is 800 per mile. For example, Palmdale Boulevard (geographically "Avenue Q-8") is 38400, Avenue Q is 38800, Avenue P is 39600, and so on. "37200 25th Street East" would be at the corner of Avenue S.


title: Palmdale, California

text: In accordance with Los Angeles County standards, odd numbers are on west and north sides of the road, and even numbers are on east and south sides of the road.


title: Palmdale, California

text: Avenue M is the general border of the connected population between Palmdale and Lancaster. Avenue L is actually the longer border between the two cities, east of Challenger Way, but is not as heavily populated. Avenue M has recently been named Columbia Way out of respect for the astronauts on board the Space Shuttle Columbia that disintegrated on re-entry in 2003. 10th Street East north of Columbia Way was renamed Challenger Way in 1987, in honor of those lost in the Challenger Disaster. (All of the shuttles were built in Palmdale.)


title: Palmdale, California

text: The Palmdale Transportation Center, completed in March 2005, is the central mass transit center for the Antelope Valley. It serves as the transit hub for the Antelope Valley Transit Authority, the city's public bus system, as well as an Amtrak, Greyhound Bus, and commuter rail Metrolink station. The station is also designated a stop on the proposed California High Speed Rail System and the proposed Orangeline Maglev rail from Irvine.


title: Palmdale, California

text: Palmdale is developing a network of bike lanes and bike paths throughout its boundaries. The backbone of the system is a new, grade separated Class A bike path on Avenue S, between 5th Street East and 25th St East, that was included as part of a $20 million highway improvement project, and a similar path on Sierra Highway, that runs from Technology Drive (Avenue P-8) north to meet with the Lancaster segment up to Avenue J. There are also bike lanes on some local streets, leading to parks and schools, as well.


title: Palmdale, California

text: Cycling in certain areas of Palmdale carries an increased risk due to higher speed limits for vehicles and also due to the presence of large vehicles.


title: Sarcopterygii

text: Sarcopterygii (; ) — sometimes considered synonymous with Crossopterygii () — is a taxon (traditionally a class or subclass) of the bony fishes known as the lobe-finned fishes. The group Tetrapoda, a mostly terrestrial superclass including amphibians, sauropsids (reptiles, including dinosaurs and therefore birds) and synapsids (with mammals being the only extant group), evolved from certain sarcopterygians; under a cladistic view, tetrapods are themselves considered a subgroup within Sarcopterygii.


title: Sarcopterygii

text: The known extant non-tetrapod sarcopterygians include two species of coelacanths and six species of lungfishes.


title: Sarcopterygii

text: Early lobe-finned fishes are bony fish with fleshy, lobed, paired fins, which are joined to the body by a single bone. The fins of lobe-finned fishes differ from those of all other fish in that each is borne on a fleshy, lobelike, scaly stalk extending from the body. The scales of sarcopterygians are true scaloids, consisting of lamellar bone surrounded by layers of vascular bone, dentine-like cosmine, and external keratin. The morphology of tetrapodomorphs, fish that are similar-looking to tetrapods, give indications of the transition from water to terrestrial life. Pectoral and pelvic fins have articulations resembling those of tetrapod limbs. The first tetrapod land vertebrates, basal amphibian organisms, possessed legs derived from these fins. Sarcopterygians also possess two dorsal fins with separate bases, as opposed to the single dorsal fin of actinopterygians (ray-finned fish). The braincase of sarcopterygians primitively has a hinge line, but this is lost in tetrapods and lungfish. Many early sarcopterygians have a symmetrical tail. All sarcopterygians possess teeth covered with true enamel.


title: Sarcopterygii

text: Most species of lobe-finned fishes are extinct. The largest known lobe-finned fish was "Rhizodus hibberti" from the Carboniferous period of Scotland which may have exceeded 7 meters in length. Among the two groups of extant (living) species, the coelacanths and the lungfishes, the largest species is the West Indian Ocean coelacanth, reaching in length and weighing up . The largest lungfish is the African lungfish which can reach 2 m (6.6 ft) in length and weigh up to .


title: Sarcopterygii

text: Taxonomists who subscribe to the cladistic approach include the grouping Tetrapoda within this group, which in turn consists of all species of four-limbed vertebrates. The fin-limbs of lobe-finned fishes such as the coelacanths show a strong similarity to the expected ancestral form of tetrapod limbs. The lobe-finned fishes apparently followed two different lines of development and are accordingly separated into two subclasses, the Rhipidistia (including the Dipnoi, the lungfish, and the Tetrapodomorpha which include the Tetrapoda) and the Actinistia (coelacanths).


title: Sarcopterygii

text: The classification below follows Benton (2004), and uses a synthesis of rank-based Linnaean taxonomy and also reflects evolutionary relationships. Benton included the Superclass Tetrapoda in the Subclass Sarcopterygii in order to reflect the direct descent of tetrapods from lobe-finned fish, despite the former being assigned a higher taxonomic rank.


title: Sarcopterygii

text: The cladogram presented below is based on studies compiled by Janvier "et al". (1997) for the "Tree of Life Web Project", Mikko's Phylogeny Archive and Swartz (2012).


title: Sarcopterygii

text: Lobe-finned fishes (sarcopterygians) and their relatives the ray-finned fishes (actinopterygians) comprise the superclass of bony fishes (Osteichthyes) characterized by their bony skeleton rather than cartilage. There are otherwise vast differences in fin, respiratory, and circulatory structures between the Sarcopterygii and the Actinopterygii, such as the presence of cosmoid layers in the scales of sarcopterygians. The earliest fossils of sarcopterygians were found in the uppermost Silurian, about 418 Ma (million years ago). They closely resembled the acanthodians (the "spiny fish", a taxon that became extinct at the end of the Paleozoic). In the early–middle Devonian (416–385 Ma), while the predatory placoderms dominated the seas, some sarcopterygians came into freshwater habitats.


title: Sarcopterygii

text: In the Early Devonian (416–397 Ma), the sarcopterygians split into two main lineages: the coelacanths and the rhipidistians. Coelacanths never left the oceans and their heyday was the late Devonian and Carboniferous, from 385 to 299 Ma, as they were more common during those periods than in any other period in the Phanerozoic. Coelacanths of the genus "Latimeria" still live today in the open (pelagic) oceans.


title: Sarcopterygii

text: The Rhipidistians, whose ancestors probably lived in the oceans near the river mouths (estuaries), left the ocean world and migrated into freshwater habitats. In turn, they split into two major groups: lungfish and the tetrapodomorphs. Lungfish radiated into their greatest diversity during the Triassic period; today fewer than a dozen genera remain. They evolved the first proto-lungs and proto-limbs, adapting to living outside a submerged water environment by the middle Devonian (397–385 Ma).


title: Sarcopterygii

text: The first tetrapodomorphs, which included the gigantic rhizodonts, had the same general anatomy as the lungfish, who were their closest kin, but they appear not to have left their water habitat until the late Devonian epoch (385–359 Ma), with the appearance of tetrapods (four-legged vertebrates). Tetrapods are the only tetrapodomorphs which survived after the Devonian.


title: Sarcopterygii

text: Non-tetrapod sarcopterygians continued until towards the end of Paleozoic era, suffering heavy losses during the Permian–Triassic extinction event (251 Ma).


title: Patsy Swayze

text: Yvonne Helen "Patsy" Swayze (née Karnes; February 7, 1927 – September 16, 2013) was an American film choreographer, dancer, and dance instructor, and the mother of actor Patrick Swayze. Her credits include choreography for "Urban Cowboy", "Liar's Moon" and "Hope Floats".


title: Patsy Swayze

text: Swayze grew up in Houston, the daughter of Gladys Mae Karnes (née Snell), a nurse, and Victor Elliott Karnes, a World War I pilot and geologist.


title: Patsy Swayze

text: When she was 10 years old, Swayze was hit by a car and her mother enrolled her in dance classes for therapy. She eventually trained in both jazz and classical ballet.


title: Patsy Swayze

text: While in high school, she met and married Jesse Wayne "Buddy" Swayze, a mechanical engineer. The couple had five children, including actors Patrick Swayze and Don Swayze. The family lived on Wakefield Street in the Garden Oaks neighborhood of Houston. They later moved to another home on Del Norte Street.


title: Patsy Swayze

text: In the 1960s, Swayze founded and directed both the Houston Jazz Ballet Company, and her own Houston dance studio, the Swayze School of Dance. All five of her children became dancers and actors, and Patsy's training has been credited for leading her son Patrick to his starring role in "Dirty Dancing" in 1987. Patrick met his future wife, film director and actress Lisa Niemi, while they were Patsy's students at the Swayze School of Dance.


title: Patsy Swayze

text: In addition to her own dance studio, for eighteen years Swayze taught dance and choreography at the University of Houston. Her most famous students included future Emmy Award winner Debbie Allen, Randy Quaid, Jaclyn Smith and future ten-time Tony Award winner Tommy Tune.


title: Patsy Swayze

text: Patsy Swayze transitioned to film by choreographing her first movie, "Urban Cowboy", starring John Travolta and Debra Winger. The success of "Urban Cowboy" essentially launched her career as a film choreographer.


title: Patsy Swayze

text: In 1981, Patsy Swayze moved from Houston to southern California. She choreographed numerous films over the next three decades, including "Liar's Moon" in 1982 and "Hope Floats" in 1998. She teamed with her daughter-in-law Lisa Niemi to choreograph the 2003 film, "One Last Dance", which starred Niemi, Patrick Swayze and George de la Peña.


title: Patsy Swayze

text: She planned to retire from teaching and focus on film work, but instead opened a dance studio in a Simi Valley shopping center that operated for more than twenty years.


title: Patsy Swayze

text: On September 8, 2013, Swayze suffered a stroke at the age of 86. Days later on September 16, she died of stroke complications at her home in Simi Valley, 2 days after her older son's 4th death anniversary.


title: Patsy Swayze

text: Swayze was predeceased by her parents; her husband, who died of a heart attack in 1982; her oldest daughter Vicky Lynn, who died of suicide in 1994 at the age of 45; her actor son Patrick, who died of pancreatic cancer in 2009 at the age of 57; her sisters, Kathryn and Diana Latham; and her brother, Elliott Karnes.


title: Stephen I of Hungary

text: Stephen I, also known as King Saint Stephen ( ; ; ; 975 – 15 August 1038), was the last Grand Prince of the Hungarians between 997 and 1000 or 1001, and the first King of Hungary from 1000 or 1001, until his death in 1038. The year of his birth is uncertain, but many details of his life suggest that he was born in, or after, 975, in Esztergom. He was given the pagan name Vajk at birth, but the date of his baptism is unknown. He was the only son of Grand Prince Géza and his wife, Sarolt, who was descended from a prominent family of "gyulas". Although both of his parents were baptized, Stephen was the first member of his family to become a devout Christian. He married Gisela of Bavaria, a scion of the imperial Ottonian dynasty.


title: Stephen I of Hungary

text: After succeeding his father in 997, Stephen had to fight for the throne against his relative, Koppány, who was supported by large numbers of pagan warriors. He defeated Koppány with the assistance of foreign knights including Vecelin, Hont and Pázmány, and native lords. He was crowned on 25 December 1000 or 1 January 1001 with a crown sent by Pope Sylvester II. In a series of wars against semi-independent tribes and chieftainsincluding the Black Hungarians and his uncle, Gyula the Youngerhe unified the Carpathian Basin. He protected the independence of his kingdom by forcing the invading troops of Conrad II, Holy Roman Emperor, to withdraw from Hungary in 1030.


title: Stephen I of Hungary

text: Stephen established at least one archbishopric, six bishoprics and three Benedictine monasteries, leading the Church in Hungary to develop independently from the archbishops of the Holy Roman Empire. He encouraged the spread of Christianity by meting out severe punishments for ignoring Christian customs. His system of local administration was based on counties organized around fortresses and administered by royal officials. Hungary enjoyed a lasting period of peace during his reign, and became a preferred route for pilgrims and merchants traveling between Western Europe, the Holy Land and Constantinople.


title: Stephen I of Hungary

text: He survived all of his children, dying on 15 August 1038 aged 62 or 63. He was buried in his new basilica, built in Székesfehérvár and dedicated to the Holy Virgin. His death was followed by civil wars which lasted for decades. He was canonized by Pope Gregory VII, together with his son, Emeric, and Bishop Gerard of Csanád, in 1083. Stephen is a popular saint in Hungary and neighboring territories. In Hungary, his feast day (celebrated on 20 August) is also a public holiday commemorating the foundation of the state, known as State Foundation Day.


title: Stephen I of Hungary

text: Stephen's birth date is uncertain as it was not recorded in contemporaneous documents. Hungarian and Polish chronicles written centuries later give three different years: 967, 969 and 975. The unanimous testimony of his three late 11th-century or early 12th-century hagiographies and other Hungarian sources, which state that Stephen was "still an adolescent" in 997, substantiate the reliability of the latest year (975). Stephen's "Lesser Legend" adds that he was born in Esztergom, which implies that he was born after 972 because his father, Géza, Grand Prince of the Hungarians, chose Esztergom as royal residence around that year. Géza promoted the spread of Christianity among his subjects by force, but never ceased worshipping pagan gods. Both his son's "Greater Legend" and the nearly contemporaneous Thietmar of Merseburg described Géza as a cruel monarch, suggesting that he was a despot who mercilessly consolidated his authority over the rebellious Hungarian lords.


title: Stephen I of Hungary

text: Hungarian chronicles agree that Stephen's mother was Sarolt, daughter of Gyula, a Hungarian chieftain with jurisdiction either in Transylvania or in the wider region of the confluence of the rivers Tisza and Maros. Many historiansincluding Pál Engel and Gyula Kristópropose that her father was identical with "Gylas", who had been baptized in Constantinople around 952 and "remained faithful to Christianity", according to Byzantine chronicler John Skylitzes. However, this identification is not unanimously accepted; historian György Györffy states that it was not Sarolt's father, but his younger brother, who was baptized in the Byzantine capital. In contrast with all Hungarian sources, the "Polish-Hungarian Chronicle" and later Polish sources state that Stephen's mother was Adelhaid, an otherwise unknown sister of Duke Mieszko I of Poland, but the reliability of this report is not accepted by modern historians.


title: Stephen I of Hungary

text: Stephen was born as Vajk, a name derived from the Turkic word "baj", meaning "hero", "master", "prince" or "rich". Stephen's "Greater Legend" narrates that he was baptized by the saintly Bishop Adalbert of Prague, who stayed in Géza's court several times between 983 and 994. However, Saint Adalbert's nearly contemporaneous "Legend", written by Bruno of Querfurt, does not mention this event. Accordingly, the date of Stephen's baptism is unknown: Györffy argues that he was baptized soon after birth, while Kristó proposes that he only received baptism just before his father's death in 997.


title: Stephen I of Hungary

text: Stephen's official hagiography, written by Bishop Hartvic and sanctioned by Pope Innocent III, narrates that he "was fully instructed in the knowledge of the grammatical art" in his childhood. This implies that he studied Latin, though some scepticism is warranted as few kings of this era were able to write. His two other late 11th-century hagiographies do not mention any grammatical studies, stating only that he "was brought up by receiving an education appropriate for a little prince". Kristó says that the latter remark only refers to Stephen's physical training, including his participation in hunts and military actions. According to the "Illuminated Chronicle", one of his tutors was a Count Deodatus from Italy, who later founded a monastery in Tata.


title: Stephen I of Hungary

text: According to Stephen's legends, Grand Prince Géza convoked an assembly of the Hungarian chieftains and warriors when Stephen "ascended to the first stage of adolescence", at the age of 14 or 15. Géza nominated Stephen as his successor and all those present took an oath of loyalty to the young prince. Györffy writes, without identifying his source, that Géza appointed his son to rule the "Nyitra ducate" around that time. Slovak historians, including Ján Steinhübel and Ján Lukačka, accept Györffy's view and propose that Stephen administered Nyitra (now Nitra, Slovakia) from around 995.


title: Stephen I of Hungary

text: Géza arranged Stephen's marriage, to Gisela, daughter of Henry II, Duke of Bavaria, in or after 995. This marriage established the first family link between a Hungarian ruler and a Western European ruling house, as Gisela was closely related to the Ottonian dynasty of Holy Roman Emperors. According to popular tradition preserved in the Scheyern Abbey in Bavaria, the ceremony took place at the Scheyern castle and was celebrated by Saint Adalbert. Gisela was accompanied to her new home by Bavarian knights, many of whom received land grants from her husband and settled in Hungary, helping to strengthen Stephen's military position. According to Györffy, Stephen and his wife "presumably" settled in Nyitra after their marriage.


title: Stephen I of Hungary

text: Grand Prince Géza died in 997. Stephen convoked an assembly at Esztergom where his supporters declared him grand prince. Initially, he only controlled the northwestern regions of the Carpathian Basin; the rest of the territory was still dominated by tribal chieftains. Stephen's ascension to the throne was in line with the principle of primogeniture, which prescribed that a father was succeeded by his son. On the other hand, it contradicted the traditional idea of seniority, according to which Géza should have been succeeded by the most senior member of the Árpád dynasty, which was Koppány at that time. Koppány, who held the title Duke of Somogy, had for many years administered the regions of Transdanubia south of Lake Balaton.


title: Stephen I of Hungary

text: Koppány proposed to Géza's widow, Sarolt, in accordance with the pagan custom of levirate marriage. He also announced his claim to the throne. Although it is not impossible that Koppány had already been baptized, in 972, most of his supporters were pagans, opponents of the Christianity represented by Stephen and his predominantly German retinue. A charter of 1002 for the Pannonhalma Archabbey writes of a war between "the Germans and the Hungarians" when referring to the armed conflicts between Stephen and Koppány. Even so, Györffy says that "Oszlar" ("Alan"), "Besenyő" ("Pecheneg"), "Kér" and other place names, referring to ethnic groups or Hungarian tribes in Transdanubia around the supposed borders of Koppány's duchy, suggest that significant auxiliary units and groups of Hungarian warriorswho had been settled there by Grand Prince Gézafought in Stephen's army.


title: Stephen I of Hungary

text: Kristó states that the entire conflict between Stephen and Koppány was only a feud between two members of the Árpád dynasty, with no effect on other Hungarian tribal leaders. Koppány and his troops invaded the northern regions of Transdanubia, took many of Stephen's forts and plundered his lands. Stephen, who, according to the "Illuminated Chronicle", "was for the first time girded with his sword", placed the brothers Hont and Pázmány at the head of his own guard and nominated Vecelin to lead the royal army. The last was a German knight who had come to Hungary in the reign of Géza. Hont and Pázmány were, according to Simon of Kéza's "Gesta Hunnorum et Hungarorum" and the "Illuminated Chronicle", "knights of Swabian origin" who settled in Hungary either under Géza or in the first years of Stephen's reign. On the other hand, Lukačka and other Slovak historians say that Hont and Pázmány were "Slovak" noblemen who had joined Stephen during his rule in Nyitra.


title: Stephen I of Hungary

text: Koppány was besieging Veszprém when he was informed of the arrival of Stephen's army. In the ensuing battle, Stephen won a decisive victory over his enemies. Koppány was killed on the battlefield. His body was quartered and its parts were displayed at the gates of the forts of Esztergom, Győr, Gyulafehérvár (Alba Iulia, Romania) and Veszprém in order to threaten all of those who were conspiring against the young monarch.