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| Goldstone |
GoldstoneGoldstone may refer to:
- goldstone, a gemstone simulant
- Goldstone Deep Space Communications Complex, a network of radio antennas in California's Mojave Desert (USA).
- The Goldstone Ground, the former stadium of Brighton & Hove Albion football club (UK).
- Richard J. Goldstone, South African judge and international war crimes prosecutor.
- Goldstone's theorem
Goldstone (gemstone)Goldstone is a type of glass made with copper or copper salts in the presence of a reducing flame. Under normal oxidative conditions, copper ions meld into the silica to produce transparent bluish-green glass; when the reduced goldstone melt cools, the copper remains in atomic isolation and precipitates into small crystalline clusters. The finished product can take a smooth polish and be carved into beads, figurines, or other artifacts suitable for semiprecious stone, and in fact goldstone is often mistaken or misrepresented as a natural material.
The most common form of goldstone gives the illusion of being reddish-brown, although in fact that color comes from the copper crystals and the glass itself is colorless. Some goldstone variants have an intensely-colored glass matrix-- usually blue or violet, more rarely green-- and a more silvery appearance to the suspended crystals, whose color may be partially masked by the glass or which may be based on different metals than copper (perhaps cobalt, manganese, or chromium).
The manufacturing process for goldstone was discovered in seventeenth-century Venice by the Miotti family, which was granted an exclusive license by the Doge. Persistent folklore attributes the discovery and secret of goldstone to an unnamed Italian monastic order, giving rise to the alternate name "monk's gold" or "monkstone".
Curiously, goldstone is one of the few cases where a synthetic simulant provided the eponymy for the similar natural stone. The original Italian name for goldstone is said to be "avventura" or some similar word or phrase indicating its accidental discovery, hence the mineral name "aventurine" for forms of feldspar or quartz with mica inclusions that give a similar glittering appearance. Yet another name for goldstone is "aventurine glass", but this should be discouraged to avoid confusion with the minerals.
Radio antenna]
Most simply, an antenna (U.S.) or aerial (UK) is an electronic component designed to transmit or receive radio waves. The words "antenna" and "aerial" are used throughout this article with precisely the same meaning.
More specifically, an antenna is an arrangement of conductors designed to radiate (transmit) an electromagnetic field in response to an applied alternating electromotive force (EMF) and the associated alternating electric current.
Alternatively, if an antenna is placed into an electromagnetic field, that field will induce an alternating current upon the antenna, and EMF between its terminals. See radio frequency induction.
Overview
There are two fundamental types of antennas. The first type is omni and the second type is directional. Omni type of antennas function in all possible directions whereas directional type of antennas work only in a single direction,i.e, "Line of Sight(LOS)". The first type couples to the electric field of an electromagnetic wave, and usually consists of a length of wire in which an electric charge moves back and forth (electric dipole). The second type couples to the magnetic field of an electromagnetic wave, and is usually a coil or loop of wire (magnetic dipole).
By adding additional conducting rods or coils (called elements) and varying their length, spacing, and orientation, an antenna with specific desired properties can be created, such as a Yagi-Uda Antenna (often abbreviated to "Yagi"). Typically, antennas are designed to operate in a relatively narrow frequency range. The design criteria for receiving and transmitting antennas differ slightly, but generally an antenna can receive and transmit equally as well. This property is called reciprocity.
The vast majority of antennas are simple vertical rods a quarter of a wavelength long. Such antennas are simple in construction, usually inexpensive, and both radiate in and receive from all horizontal directions (omnidirectional). One limitation of this antenna is that it does not radiate or receive in the direction in which the rod points. This region is called the antenna blind cone or null.
Antennas have practical use for the transmission and reception of radio frequency signals (radio, TV, etc.), which can travel over great distances at the speed of light, and pass through nonconducting walls (although often there is a variable signal reduction depending on the type of wall, and natural rock can be very defective to radio signals).
Antenna effectiveness
Antennas may be omni and directional. There are several critical parameters that affect an antenna's performance and can be adjusted during the design process. These are resonant frequency, impedance, gain, aperture or radiation pattern, polarization, efficiency and bandwidth. Transmit antennas may also have a maximum power rating, and receive antennas differ in their noise rejection properties.
Resonant frequency
The resonant frequency is related to the electrical length of the antenna.
This is usually the physical length of the wire multiplied by the ratio of the speed of wave propagation in the wire. Typically an antenna is tuned for a specific frequency, and is effective for a range of frequencies usually centered on that resonant frequency. However, the other properties of the antenna (especially radiation pattern and impedance) change with frequency, so the antenna's resonant frequency may merely be close to the center frequency of these other more important properties.
Antennas can be made resonant on harmonic frequencies and with lengths that are fractions of the target frequency. Some antenna designs have multiple resonant frequencies, and some are relatively effective over a very broad range of frequencies. The most commonly known type of wide band aerial is the logarithmic or log aerial but its gain is usually much lower than that of a specific or narrower band aerial.
Impedance
Impedance is similar to refractive index in optics. As the electric wave travels through the different parts of the antenna system (radio, feed line, antenna, free space) it may encounter differences in impedance. At each interface, some fraction of the wave's energy will reflect back to the source, forming a standing wave in the feed line. The ratio of maximum power to minimum power in the wave can be measured and is called the standing wave ratio (SWR). A SWR of 1:1 is ideal. A SWR of 1.5:1 is considered to be marginally acceptable in low power applications where power loss is more critical, although an SWR as high as 6:1 may still be usable with the right equipment. Minimizing impedance differences at each interface will reduce SWR and maximize power transfer through each part of the antenna system.
Complex impedance of an antenna is related to the electrical length of the antenna at the wavelength in use. The impedance of an antenna can be matched to the feed line and radio by adjusting the impedance of the feed line, using the feed line as an impedance transformer. More commonly, the impedance is adjusted at the load (see below) with an antenna tuner, a balun, a matching transformer, matching networks composed of inductors and capacitors, or matching sections such as the gamma match.
Gain
capacitor
An antenna has gain if it radiates more strongly in one direction than in another. Gain is measured by comparing an antenna to a model antenna, typically the isotropic antenna which radiates equally in all directions. Often a dipole is also used as a practical reference as the isotropic source cannot be realised in practice, but it has 2.1 dB gain over an isotropic source. Most practical antennas radiate more than the isotropic antenna in some directions and less in others. Gain is inherently directional; the gain of an antenna is usually measured in the direction which it radiates best. Gain is one-dimensional. Gain does not mean that the antenna radiates more power than is fed to it, merely that it distributes the power more strongly in some directions than in others.
Aperture, and radiation pattern are closely related to gain.
Aperture is the shape of the "beam" cross section in the direction of highest gain, and is two-dimensional. (Sometimes aperture is expressed as the radius of the circle that approximates this cross section or the angle of the cone.)
Radiation pattern is the three-dimensional plot of the gain, but usually only the two-dimensional horizontal and vertical cross sections of the radiation pattern are considered. Antennas with high gain typically show side lobes in the radiation pattern. Side lobes are peaks in gain other than the main lobe (the "beam"). Side lobes detract from the antenna quality whenever the system is being used to determine the direction of a signal, as in radar systems.
Efficiency
Efficiency is the ratio of power actually radiated to the power put into the antenna terminals. A dummy load may have a SWR of 1:1 but an efficiency of 0, as it absorbs all power and radiates none, showing that SWR alone is not an effective measure of an antenna's efficiency. Radiation in an antenna is caused by radiation resistance which can only be measured as part of total resistance including loss resistance.
Bandwidth
The bandwidth of an antenna is the range of frequencies over which it is effective, usually centered around the resonant frequency. The bandwidth of an antenna may be increased by several techniques, including using thicker wires, replacing wires with cages to simulate a thicker wire, tapering antenna components (like in a feed horn), and combining multiple antennas into a single assembly and allowing the natural impedance to select the correct antenna.
Small antennas are usually preferred for convenience, but there is a fundamental limit relating bandwidth, size and efficiency.
Of the parameters above, SWR is most easily measured. Impedance can be measured with specialized equipment, as it relates to the complex SWR. Measuring radiation pattern requires a sophisticated setup including significant clear space (enough to get into the antenna's far field) or an anechoic chamber designed for antenna measurements, careful study of experiment geometry, and specialised measurement equipment such as robots that rotate the antenna during the measurements.
Bandwidth depends on the overall effectiveness of the antenna, so all of these parameters must be understood to understand bandwidth. However, typically bandwidth is measured by only looking at SWR, i.e., by finding the frequency range over which the SWR is less than a given value. Bandwidth over which an antenna exhibits a particular radiation pattern might also be considered.
Polarization
The polarization of an antenna or orientation of the radio wave is determined by the electric field or E-plane. The ionosphere changes the polarization of signals unpredictably, so for signals which will be reflected by the ionosphere, polarization is not crucial. However, for line-of-sight communications, it can make a tremendous difference in signal quality to have the transmitter and receiver using the same polarization. Polarizations commonly considered are linear, such as vertical and horizontal, and circular, which is divided into right-hand and left-hand circular.
Transmission and receiving
All of these parameters are expressed in terms of a transmission antenna, but are identically applicable to a receiving antenna, due to reciprocity. Impedance, however, is not applied in an obvious way; for impedance, the impedance at the load (where the power is consumed) is most critical. For a transmitting antenna, this is the antenna itself. For a receiving antenna, this is at the (radio) receiver rather than at the antenna.
Antennas used for transmission have a maximum power rating, beyond which heating, arcing or sparking may occur in the components, which may cause them to be damaged or destroyed. Raising this maximum power rating usually requires larger and heavier components, which may require larger and heavier supporting structures. Of course, this is only a concern for transmitting antennas; the power received by an antenna rarely exceeds the microwatt range.
If an antenna is to be used for reception at very low frequencies (below about ten megahertz), its noise rejection capabilities become important. At such frequencies, signals are reflected very effectively by the ionosphere; however, at these frequencies there are many forms of natural radio noise, including the noise produced by lightning. Successfully rejecting these forms of noise is an important antenna feature. For example, a small coil of wire with many turns is more able to reject such noise than a vertical antenna. However, the vertical will radiate much more effectively on transmit, where extraneous signals are not a concern.
Theoretical antenna types
- A dielectric resonator is a variation on the conventional antenna in which an insulator with a large dielectric constant is used to modify the electromagnetic field. It is claimed that the dielectric contains the antenna's near field and therefore prevents it from interfering with other nearby antennas or circuits, making it suitable for miniature equipment such as mobile phones.
- A feedhorn is an antenna system that handles the incoming waveform from the dish to the focal point. It usually comprises of a series of rings with decreasing radius in order to drive the signal to the polarizer.
- An isotropic radiator is an antenna that radiates equally in all directions. It is considered to be a point in space with no dimensions and no mass. Most antennas' gains are measured with reference to an isotropic radiator, and are rated in dBi (decibels with respect to an isotropic radiator). This antenna type is purely theoretical and is not achievable in real life.
Practical antenna models
There are many variations of antennas, but here are a few common models.
More can be found in :Category:Radio frequency antenna types.
- The dipole antenna is simply two wires pointed in opposite directions arranged either horizontally or vertically, with one end of each wire connected to the radio and the other end hanging free in space. Variations of the dipole include the folded dipole and the whip antenna which is really just half of a dipole using a ground plane as the image of the second half. The dipole antenna is usually a multiple of a half wavelength long. For this reason, the dipole antenna is sometimes referred to as the half-wave antennna. Generally, the dipole is considered to be omnidirectional in the plane perpendicular to the axis of the antenna, but it has deep nulls in the directions of the axis. The popular J-pole antenna is a variation of the half dipole with a built in quarter wave transmission line impedance matching section.
- The yagi-Uda antenna is a directional variation of the dipole with parasitic elements added with functionality similar to adding a reflector and lenses (directors) to focus a filament lightbulb.
- The groundplane antenna takes the form of a driven vertical element 1/4 wave long in the center of a grounded plane 1/2 wave in diameter. The end of the vertical element nearest the ground plane is connected to the radio, and the far end is in hanging in free space. The ground plane can take the form of the natural Earth surface, or a network of wires and ground rods, or a solid metal sheet, or four wires arranged as two crossed dipoles and centrally connected to ground.
- The (large) loop antenna is similar to a dipole, except that the ends of the dipole are connected to form a circle, triangle (delta loop antenna) or square. Typically a loop is a multiple of a half or full wavelength in circumference. A circular loop gets higher gain (about 10%) than the other forms of large loop antenna, as gain of this antenna is directly proportional to the area enclosed by the loop, but circles can be hard to support in a flexible wire, making squares and triangles much more popular. Large loop antennas are more immune to localized noise partly due to lack of a need for a groundplane. The large loop has its strongest signal in the plane of the loop, and nulls in the axis perpendicular to the plane of the loop.
- The small loop antenna, also called the magnetic loop antenna is a loop of wire (in other words, both ends of the wire connect to the radio) less than a wavelength in circumference. Typically, the circumference is less than 1/10 for a receiving loop, and less than 1/4 for a transmitting loop. Unlike nearly all other antennas in this list, this antenna detects the magnetic component of the electromagnetic wave. As such, it is less sensitive to near field electric noise when properly shielded. The receiving aperture can be greatly increased by bringing the loop into resonance with a tuning capacitor. Due to the small size of the loop, the radiation pattern is 90 degrees from that of the large loop. The radiation pattern is perpendicular to the plane of the loop, with sharp nulls in the plane of the loop.
- The electrically short antenna is an open-end wire far less than 1/4 wavelength in length - in other words only one end of the antenna is connected to the radio, and the other end is hanging free in space. Unlike nearly all other antennas in this list, this antenna detects only the electric field of the wave instead of the electromagnetic field - think of the free end of the wire as measuring the voltage of that point in space, as opposed to measuring both the voltage and the magnetic field. Its receiving aperture can be greatly increased by increasing the voltage; by adding an inductor or resonator tuned to resonance with the signals of interest. Electrically short antennas are typically used where operating wavelength is large and space is limited, e.g. for mobile transceivers operating at long wavelengths.
- The microstrip antenna consists of a patch of metalization on a ground plane. These are low profile, light weight antennas, most suitable for aerospace and mobile applications. Because of their low power handling capability, these antennas can be used in low-power transmitting and receiving applications. Microstrip antennas are the most commonly used antennas in mobile communications, satellite links, W-LAN and so on because circuit functions can be directly integrated to the microstrip antenna to form compact tranceivers and spatial power combiners.
- The quad antenna is an array of square loops that vary in size. The quad is related to the loop in exactly the same way the yagi is related to the dipole. Typically, the quad needs fewer elements to get the same gain as a yagi. Variations of the quad include the delta loop antenna which uses a triangle instead of a square, requiring fewer supports for large wavelength antennas.
- The random wire antenna is simply a very long (greater than one wavelength) wire with one end connected to the radio and the other in free space, arranged in any way most convenient for the space available. Folding will reduce effectiveness and make theoretical analysis extremely difficult. (The added length helps more than the folding typically hurts.) Typically, a random wire antenna will also require an antenna tuner, as it might have a random impedance that varies nonlinearly with frequency.
- The Beverage antenna is a form of directional long-wire antenna which uses a resistive termination at one end and feed from the other.
- The helical antenna is a directional antenna suited for receiving signals that are either circular polarized or randomly polarized. These are usually used with satellites, and are frequently used for the driven element on a dish.
- The Phased array antenna is a group of independently fed active elements in which the relative phases of the respective signals feeding the elements are varied in such a way that the effective radiation pattern of the array is reinforced in a desired direction and suppressed in undesired directions. In plain language, this is a directional antenna that can be aimed without moving any parts.
- Synthetic aperture radar uses a series of observations separated in time and space to simulate a very large antenna. More generally, interferometry allows the combining of signals from several radio receivers or a single moving receiver.
- A trailing wire antenna is used by submarines when submerged. These antennas are designed to pick up transmissions in the low frequency (LF) and very low frequency (VLF) ranges.
- An evolved antenna refers to an antenna fully or substantially designed using a computer algorithm based on Darwinian evolution.
See also
- :Category:Radio frequency antenna types
- :Category:Antenna_terminology
- List of antenna terms
- antenna height above average terrain
- antenna effective area
- electromagnetism
- WiFi
- Satellite television
- Amateur Radio
- radiotelescope
- RF connector
External links
- [http://hamradio.co.in/tcvr/antena.php Antenna] Antena for Ham / Amateur Radio
- [http://www.maxstream.net/helpdesk/article-27 dBi vs. dBd] How to measure antenna gain
- [http://www.radio-electronics.com/info/antennas/index.php Radio-Electronics.Com] Further information regarding antennas
- [http://www.dxzone.com/catalog/Antennas/ Antenna Plans] Over 400 amateur radio antenna plans and documents from [http://www.dxzone.com dxzone.com]
- [http://www.vias.org/simulations/simusoft_twoaerials.html Learning by Simulations] Interactive simulation of two coupled antennas
- [http://www.n0hr.com/total NØHR.com Best Ham Radio Links] Ham radio antenna sites sorted by band, design, and homebrew vs. commercial antenna products.
-
Category:Amateur radio
Category:Electrical components
Category:Radio electronics
ms:Antena
ja:空中線
California
California is a state located on the west coast of the United States. It is by far the most populous state in the U.S., as well as the most physically diverse, with the highest and the lowest points in the lower 48 states located within 150 miles of each other. If California were an independent nation, it would have the sixth largest economy in the world (after the rest of the U.S., Japan, Germany, Britain and France; see economy of California). The state's official nickname is "The Golden State" in reference to California's 1849 Gold Rush. California's U.S. postal abbreviation is CA, and its Associated Press abbreviation is Calif.
As one of the most demographically diverse states in the nation, California is a dominant force in American culture as well as the nation's economy. It has some of the nation's largest cities, including Los Angeles, San Diego, San Jose, and San Francisco, and is responsible for many legal and technological innovations.
The entire region originally known as California was composed of the Mexican peninsula now known as Baja California and much of the land in the current states of California, Nevada, Utah, Arizona and Wyoming, known as Alta California. In these early times, the boundaries of the Sea of Cortez and the Pacific coast were only partially explored and California was shown on early maps as an island. The name comes from Las sergas de Esplandián (Adventures of Splandian), a 16th century novel, by Garci Rodríguez de Montalvo, where there is an island paradise called California. (For further discussion, see: Origin of the name California.)
History
:Main articles: History of California, History of California (20th century)
The first European to explore parts of the coast was the Portuguese João Rodrigues Cabrilho in 1542. The first to explore the entire coast and claim possession of it was Francis Drake in 1579. Beginning in the late 1700s, Spanish missionaries set up tiny settlements on enormous grants of land in the vast territory north of Baja California. The missions played a dominant role in the decimation of California's indigenous population. Upon Mexican independence from Spain, the chain of missions became the property of the Mexican government, and they were quickly dissolved and abandoned.
In 1846, at the outset of the Mexican-American War, the California Republic was founded and the Bear Flag was flown, which featured a golden bear and a star. The Republic came to a sudden end, however, when Commodore John D. Sloat of the United States Navy sailed into San Francisco Bay and claimed California for the United States. Following the war, the region was divided between Mexico and the United States. The Mexican portion, Baja (lower) California was later divided into the states of Baja California and Baja California Sur. The western part of the U.S. portion, Alta (upper) California, was to become the state of California.
In 1848, the Spanish-speaking population of distant upper California numbered around 4,000. But after gold was discovered, the population burgeoned with Americans and a few Europeans in the great California gold rush. In 1850, the state was admitted to the Union of the USA.
During the American Civil War, popular support in California was divided 70% for the South and 30% for the North, and although California officially entered on the side of the North, many troops went east to fight for the Confederacy CSA.
At first, travel between the far Pacific West to the eastern population centers was time-consuming and dangerous, requiring either long ocean voyages, or difficult transcontinental passages. A more direct connection came in 1869 with the completion of the first transcontinental railroad. After this rail link was established, hundreds of thousands of Americans came west, where new Californians were discovering that land in the state, if irrigated during the dry summer months, was extremely well suited to fruit cultivation and agriculture in general. Citrus, oranges in particular, was widely grown, and the foundation was laid for the state's prodigious agricultural production of today.
During the early 20th century, migration to California accelerated with the completion of major transcontinental highways like the Lincoln Highway and Route 66. In the period from 1900 to 1965 the population grew from fewer than one million to become the most populous state in the Union. From 1965 to the present, the population demographic changed radically and became one of the most diverse in the world. The state is generally liberal-leaning, technologically and culturally savvy, and a world center of engineering businesses, the film and television industry and, as mentioned above, American agricultural production.
Law and government
California is governed as a republic, with three branches of government, the executive branch consisting of the Governor of California and the other independently elected constitutional officers, the legislative branch consisting of the Assembly and Senate, and the judicial branch consisting of the Supreme Court of California and lower courts. The state also allows direct participation of the electorate by referendum, recall, and ratification.
The Governor of California and the other state constitutional officers serve four-year terms and may be re-elected only once. The California State Legislature consists of a 40 member Senate and 80 member Assembly. Senators serve four year terms and Assembly members two. The terms of the Senators are staggered so that half the membership is elected every two years. The Senators representing the odd-numbered districts are elected in years evenly divisible by four, i.e., presidential election years. The Senators from the even-numbered districts are elected in the intervening even-numbered years, in the gubernatorial election cycle. California's legislature is organized in such a way that the party caucus leaders wield great power and can usually speak on behalf of their caucuses. Many important legislative decisions are thus not made on the floor of the legislature but in back-room deals by the "Big Five", which comprises the governor and the Democratic and Republican leaders of each chamber.
For the 2005–2006 session, there are 48 Democrats and 32 Republicans in the Assembly. In the Senate, there are 25 Democrats and 15 Republicans. The current Governor is the Republican Arnold Schwarzenegger, whose current term lasts through January 2007. Schwarzenegger was only the second person in the history of the United States to be put into office by a recall of a sitting governor (the first was the 1921 recall of North Dakota Governor Lynn J. Frazier). Schwarzenegger replaced Governor Gray Davis (1999–2003), who was removed from office by the October 2003 California recall election.
The state's capital is Sacramento. During California's early history under European control, the capital was successively located in Monterey (1775–1849), San Jose (1849–1851), Vallejo (1852–1853), Benicia (1853–1854), and San Francisco (1862). The capital moved to Sacramento temporarily in 1852 when construction on a State House could not be completed in time in Vallejo. The capital's final move to Sacramento was on February 25, 1854 where it has been permanently, except for a four-month temporary move in 1862 to San Francisco, due to severe flooding in Sacramento.
California's giant judiciary is the largest in the United States (with a total of 1,600 judges, while the federal system has only about 840). It is supervised by the seven Justices of the Supreme Court of California. Justices of the Supreme Court and Courts of Appeal are appointed by the Governor, but are subject to retention by the electorate every 12 years. Judges of the trial courts, the Superior Courts in each county, may be appointed by the Governor or elected directly by the voters, depending on when the vacancy occurs. Superior Court judges serve six-year terms, after which they may run for re-election. Unlike the retention elections for Supreme Court and Court of Appeal justices, Superior Court judges run for re-election in open races, in which other qualified candidates may run as challengers.
California's legal system is explicitly based on English common law but carries a few features from Spanish civil law. Capital punishment is a legal form of punishment and the state has the largest "Death Row" population in the country.
At the national level, California is represented by two senators and 53 representatives, as of 2005. It has 55 electoral votes in the U.S. Electoral College. (As California is the most populous state in the Union, its counts of Congressmen and Presidential Electors are, of course, also the largest.) The two U.S. Senators from California are Democrats Dianne Feinstein and Barbara Boxer. 33 Democrats and 20 Republicans represent the state in the U.S. House of Representatives.
While California is among the most Democratic and liberal states in the nation because of the large concentration of voters in populous areas, much of California is politically very conservative, notably the Central Valley, the Inland Empire, Orange and San Diego counties, and most inland, eastern, and rural areas. Democratic bastions are mostly coastal and include the entire San Francisco Bay Area, Los Angeles, Salinas, Santa Barbara, and Imperial County. The state has supported Democrats in the last four presidential elections. In 2004, Republican President George W. Bush received a majority of votes in more than half the state's 58 counties, but still lost California's 55 electoral votes to John Kerry, who won 54.3% of the popular vote, by a margin of 10 percentage points.
See also: List of California Governors, U.S. Congressional Delegations from California, List of California counties, List of California ballot propositions
Geography
California borders the Pacific Ocean, Oregon, Nevada, Arizona, and the Mexican state of Baja California. The state has strikingly beautiful natural features, including an expansive central valley, tall mountains, hot deserts, and hundreds of miles of scenic coastline. With an area of 411,000 km² it is the third largest state in the U.S and larger than Germany in size. Most major cities cling to the cool seacoast along the Pacific, notably Los Angeles, San Francisco, San Jose, Santa Ana/Orange County, and San Diego. However, the capital, Sacramento is in the Central Valley.
California has extremely varied geography. In the center of the state lies the Central Valley, a huge, fertile valley bounded by the coastal mountain ranges in the west, the granite Sierra Nevada to the east, the volcanic Cascade Range in the north and the Tehachapi Mountains in the south. Mountain-fed rivers, dams, and canals provide water to irrigate the Central Valley. With dredging, several of these rivers have become sufficiently large and deep that several inland cities, notably Stockton, California, are seaports. The hot, fertile Central Valley is California's agricultural heartland and grows a large portion of America's food, yet near freezing temperatures are not uncommon during winter which sometimes wipe out portions of crops. The bottom part of the valley, which is part desert, is known as the San Joaquin Valley while the upper half is known as the Sacramento Valley.
In the center and east of the state are the Sierra Nevada (meaning Snowy Range in Spanish), containing the highest peak in the contiguous lower 48 states, Mount Whitney, at 14,505 feet (4421 m). Also located in the Sierra are the world famous Yosemite National Park and a deep freshwater lake, Lake Tahoe, the largest lake in the state by volume. To the east of the Sierra are Owens Valley and Mono Lake, an essential seabird habitat. To the west is Clear Lake, California's largest freshwater lake by area. The Sierra Nevada receives arctic temperatures in the winter and holds several dozen small glaciers, including the most southern glacier in the United States (Palisade Glacier).
California has about 35% of its total surface area covered by forests. California's diversity of pine species is unmatched by any other state. Though other states have a higher percentage of their land area covered by forests, in terms of total area, California contains more forestland than any other state except Alaska. Most of the forest is found in 2 places. First, in the northwestern part of the state and along the western slope of the Sierra Nevada. Smaller forests, mainly consisting of oaks, can be found along the coast ranges of California closer to the coast, and also in the foothills of the Sierra Nevada. Smaller areas of pine forests can be found in the San Gabriel and San Bernardino mountains of Southern California and also in the mountain areas of Central San Diego Country.
Deserts in California make up about 25% of the total surface area. In the south lie the Transverse Ranges and a large salt lake, the Salton Sea. The south-central desert is called the Mojave. To the northeast of the Mojave lies Death Valley, which contains the lowest, hottest point in North America. The lowest point of Death Valley and the peak of Mount Whitney are less than 200 miles apart. The hiking trek between the two points has been attempted, several times, most notably by Lee Bergthold. Indeed, almost all of southeastern California is arid, hot desert, with the Coachella Valley routinely experiencing extreme high temperatures during the summer.
Finally, along the densely-populated but long California coast lie a number of major metropolitan areas, including San Francisco Bay, Los Angeles, and San Diego. Climates near the Pacific Ocean are remarkably moderate compared with inland climates. Winter temperatures never reach freezing (snow is unheard of) and summer temperatures rarely reach above the high 80's Fahrenheit (27 °C).
California is famous for its earthquakes, due partly to the presence of the San Andreas Fault. While more powerful earthquakes in the United States have occurred in Alaska and along the Mississippi River, California earthquakes are notable in their frequency and location in highly populated areas. Some people believe, eventually, a huge earthquake will result in the splitting of coastal California from the continent, either to sink into the ocean or form a new landmass. The fact that this scenario is completely implausible from a geologic standpoint does not lessen its acceptance in public conventional wisdom, or its exploitation by the producers of science fiction and fantasy media. Notable movies in which the possible destruction of much of California by an earthquake includes the titles Earthquake, A View to a Kill, Escape from L.A. and Superman.
California is also home to several volcanoes, some active such as Mammoth Mountain. Other volcanoes include Lassen Peak, which erupted from 1914 and 1921, and Mount Shasta.
Climate
Different regions of California have very different climates, depending on their latitude, elevation, and proximity to the coast. Most of the state has a Mediterranean climate, with rainy winters and dry summers. The influence of the ocean generally moderates temperature extremes, creating warmer winters and substantially cooler summers, and the cold oceanic California Current offshore often creates summer fog near the coast. As one moves away from the coast, the climate becomes more continental, with colder winters and markedly hotter summers. The temperature gradient between immediate coast and low-lying inland valleys in the north is about 7 °F (4 °C) in winter, coast being warmer, and in summer roughly 25 °F (14 °C) but opposite. In the south, the figures are approximately 4 and 23 °F (2 °C and 13 °C), respectively; however 4 °F and 35 °F (2 °C and 20 °C) between Santa Barbara and Death Valley.
Westerly winds from the ocean also bring moisture, and the northern parts of the state generally receive higher rainfall than the south. California's mountain ranges influence the climate as well: moisture-laden air from the west cools as it ascends the mountains, dropping moisture; some of the rainiest parts of the state are west-facing mountain slopes. Northwestern California has a temperate climate with rainfall of 15–40 inches (400–1000 mm) per year. The Central Valley has a Mediterranean climate, but with greater temperature extremes than the coastal areas; parts of the valley are often filled with thick fog, similar to that found in the coastal valleys. The high mountains, including the Sierra Nevada, have a mountain climate with snow in winter and mild to moderate heat in summer.
On the east side of the mountains is a drier "rain shadow." California's desert climate regions lie east of the high Sierra Nevada and southern California's Transverse Ranges and Peninsular Ranges. The low deserts east of the southern California mountains, including the Imperial and Coachella valleys and the lower Colorado River, are part of the Sonoran Desert, with hot summers and mild winters; the higher elevation deserts of eastern California, including the Mojave Desert, Owens Valley, and the Modoc Plateau, are part of the Great Basin region, with hot summers and cold winters.
Death Valley, in the northern portion of the Mojave Desert on the east side of the state, is the hottest spot on the Western Hemisphere, with high temperatures over 120 °F common in the summer. The highest temperature in the Western Hemisphere, 134 °F (56.6 °C), was recorded in Death Valley on July 10, 1913. Temperatures of 130 °F or higher have been recorded as recently as 2005. The 24-hour average July temperature in Death Valley is 101 °F (38 °C) (1961--1990 standard).
Ecology
Ecologically, California is one of the richest and most diverse parts of the world, and includes some of the most endangered ecological communities. California's diverse geography, geology, soils and climate have generated a tremendous diversity of plant and animal life. The State of California is part of the Nearctic ecozone, and spans a number of terrestrial ecoregions, and is perhaps the most ecologically diverse state in the United States.
California has a rather high percentage of endemic species. California endemics include relict species that have died out elsewhere, including the redwoods and the Catalina Ironwood (Lyonothamnus floribundus). Many other endemics originated through differentiation or adaptive radiation, whereby multiple species develop from a common ancestor to take advantage of diverse ecological conditions. California's great abundance of species of California lilac (Ceanothus) is an example of adaptive radiation. Many California endemics have become endangered, as urbanization, logging, overgrazing, and the introduction of exotic species have encroached on their habitat. Furthermore, California is home to the largest trees in the world, the Giant Sequoias.
California's native grasses were perennials, which stayed green year-round in most of the state's subclimates. After European contact, these were generally replaced by invasive species of European annual grasses; and, in modern times, California's hills turn a characteristic golden brown in summer and fall. California's nickname The Golden State is in reference to the California Gold Rush, and not to the golden brown summer hillsides as is sometimes stated.
Economy
California Gold Rush
California Gold Rush]
California has the fifth largest economy in the world. It is responsible for 14% of the United States' gross domestic product (GDP). The gross state product (GSP) is about $1.5 trillion ($1,500,000,000,000, as of 2004), making it greater than that of every other U.S. state, and most countries in the world (by Purchasing Power Parity).
The predominant industry, more than twice as large as the next, is agriculture, (including fruit, vegetables, dairy, and wine). This is followed by aerospace; entertainment, primarily television by dollar volume, although many movies are still made in California; and light manufacturing including computer hardware and software, and the mining of borax.
Per capita personal income was $33,403 as of 2003, ranking 12th in the nation. Per capita income varies widely by geographic region and profession. The Central Valley has the most extreme contrasts of income, with migrant farm workers making less than minimum wage. While some coastal cities include some of the wealthiest per-capita areas in the U.S., notably San Francisco and Marin County, the non-agricultural central counties have some of the highest poverty rates in the U.S. The high-technology sectors in Northern California, specifically Silicon Valley, in Santa Clara and San Mateo counties, are currently emerging from economic downturn caused by the dot.com bust, which caused the loss of over 250,000 jobs in Northern California alone. Recent (Spring 2005) [http://uclaforecast.com economic data] indicates that economic growth has resumed in California, although still slightly below the national annualized forecast of 3.9%. The international boom in housing prices has been most pronounced in California, with the median property price in the state rising to about the half-million dollar mark in April 2005.
Demographics
Population
As of 2004 California had a population of 35,893,799. The state had 9,400,000 foreign-born residents (26.5% of the population), of which an estimated 2,209,000 were illegal aliens (illegal aliens accounted for nearly one-fourth of the foreign-born population and 6.2% of the total state population).
California is the most populous state—more than 12 percent of Americans live in the state. California's population is larger than all but 33 countries; more populated than Canada.
Racial and Ancestral Makeup
The Census Bureau considers race and Hispanic origin to be two separate categories. Hispanics must not only select "Hispanic"; they must also select a race such as White or Asian, or, simply "some other race." This makes interpreting Census data difficult. Thus, for the sake of simplicity, the data below does consider Hispanic origin to be its own category. It therefore shows only non-Hispanic members of each group: non-Hispanic Whites, non-Hispanic Eskimos, non-Hispanic people of two or more races, etc. For more information on race and the Census, see [http://en.wikipedia.org/wiki/Race_%28U.S._Census%29 here].
California lacks a majority ethnic group. It is the third minority-majority state, after Hawaii and New Mexico. Non-Hispanic Whites are still the largest group, but are no longer a majority of the population due to high levels of immigration in recent years. Hispanics make up over one-third of the population; in order, other groups are Asians, Blacks, and Native Americans.
Because of high levels of immigration from Latin America, especially Mexico, and higher birth rates among the Hispanic population, Hispanics are predicted to become a majority in the state around 2040. California has the second-largest Asian population (percentage-wise) of any state, Hawaii having the largest.
The largest ancestries in California are Mexican (25%), Filipino, German, Irish, and Asian. Mexicans and Chicanos predominate in Southern California, the Central Valley, Salinas, and parts of the San Francisco Bay area. Irish and German ancestries are dominant in the eastern Sierra Nevada, the far north, and the North Coast. San Francisco has the greatest concentration of Asians in the continental United States, with Chinese numerous in San Francisco, Alameda, and Santa Clara counties and Filipinos particularly numerous in San Mateo county.
Languages
As of 2000, 60.5% of California residents age 5 and older speak English at home and 25.8% speak Spanish. Chinese is the third most spoken language at 2.6%, followed by Tagalog at 2.5% and Vietnamese at 1.3%. The indigenous languages of California number more than one hundred, but most are in danger of language death, despite revitalization efforts. Since 1986, the California Constitution has specified English as the common and official language of the state. The politics of language, particularly concerning language policy regarding the teaching and official use of immigrant languages is a major political issue in the state.
Religion
The religious affiliations of the people of California:
- Christian – 75%
- Protestant – 38%
- Baptist – 8%
- Presbyterian – 3%
- Methodist – 2%
- Lutheran – 2%
- Other Protestant or general Protestant – 23%
- Roman Catholic – 34%
- Other Christian – 3%
- Jewish – 2%
- Other Religions – 3%
- Non-Religious – 20%
As with many other western states, the percentage of California's population identifying themselves as "non-religious" is comparatively high in relation to the rest of the U.S.
Important cities and towns
Image:Sacramento from Riverwalk.jpg|Sacramento
Image:DowntownLosAngeles.jpg|Los Angeles
Image:Sandiego.arp.750pix.jpg|San Diego
Image:Lightmatter sanfrancisco.jpg|San Francisco
Image:SanJoseDowntownIMG016elf wb.jpg|San Jose
Image:Long Beach, CA at night.jpg|Long Beach
Image:La2-oakland.jpg|Oakland
Image:Anaheimdland.jpg|Anaheim
The state of California has 478 cities, the majority of which are within one of the large metropolitan areas. 68% of California's population lives in its two largest metropolitan areas, Greater Los Angeles and the San Francisco Bay Area.
- Population greater than 10,000,000 (urbanized area)
- Los Angeles/Long Beach (Greater Los Angeles)
- Population greater than 5,000,000 (urbanized area)
- San Francisco/Oakland/San Jose/Santa Rosa (San Francisco Bay Area)
- Population greater than 2,500,000 (urbanized area)
- San Diego
- Orange County
- Inland Empire (Riverside/San Bernardino)
- Population greater than 1,000,000 (urbanized area)
- Fresno
- Sacramento
- Population greater than 500,000 (urbanized area)
- Bakersfield
- Stockton
- Oxnard/Ventura (Ventura County)
- Population greater than 250,000 (urbanized area)
- Visalia/Tulare/Porterville (Tulare County)
- Modesto
- Salinas/Monterey (Monterey County)
- Santa Barbara/Goleta/Santa Maria (Santa Barbara County)
- Palmdale/Lancaster (Antelope Valley)
- Indio/Palm Springs (Coachella Valley)
For a list of important suburbs within the above areas, see List of urbanized areas in California (by population).
25 wealthiest places in California
Thanks to the state's powerful economy, certain California cities are among the wealthiest on the planet. The following list is ranked by per capita income:
1 Belvedere, California - Marin County - $113,595
2 Rancho Santa Fe, California - San Diego County - $113,132
3 Atherton, California - San Mateo County - $112,408
4 Rolling Hills, California - Los Angeles County - $111,031
5 Woodside, California - San Mateo County - $104,667
6 Portola Valley, California - San Mateo County - $99,621
7 Newport Coast, California - Orange County - $98,770
8 Hillsborough, California - San Mateo County - $98,643
9 Diablo, California - Contra Costa County - $95,419
10 Fairbanks Ranch, California - San Diego County - $94,150
11 Hidden Hills, California - Los Angeles County - $94,096
12 Los Altos Hills, California - Santa Clara County - $92,840
13 Tiburon, California - Marin County - $85,966
14 Sausalito, California - Marin County - $81,040
15 Monte Sereno, California - Santa Clara County - $76,577
16 Indian Wells, California - Riverside County $76,187
17 Malibu, California - Los Angeles County - $74,336
18 Del Monte Forest, California - Monterey County - $70,609
19 Piedmont, California - Alameda County - $70,539
20 Montecito, California - Santa Barbara County - $70,077
21 Palos Verdes Estates, California - Los Angeles County - $69,040
22 Emerald Lake Hills, California - San Mateo County - $68,966
23 Loyola, California - Santa Clara County - $68,730
24 Blackhawk-Camino Tassajara, California - Contra Costa County - $66,972
25 Los Altos, California - Santa Clara County - $66,776
Note: Marin County ranks as the wealthiest county in the United States based on per capita personal income.
Education
Image:Berkeley glade afternoon.jpg|UC Berkeley
Image:Stanford campus aerial photo.jpg|Stanford
Image:USC Bovard Auditorium enh.jpg|USC
Image:RHall.JPG|UCLA
Image:Tower Hall and MDA.JPG|San Jose State
Image:UCSD_lib1024.jpg|UC San Diego
Image:Millikan Library.jpg|Caltech
Image:Csulb pyramid.jpg|CSU Long Beach
California's public educational system is supported by a unique constitutional amendment that requires 40% of state revenues to be spent on education.
The preeminent state university is the University of California, which employs more Nobel Prize winners than any other institution in the world and is considered one of the finest public higher-education systems in the country. The nine general UC campuses are in Berkeley, Los Angeles, San Diego, Davis, Santa Cruz, Santa Barbara, Irvine, Riverside, and Merced. The University of California, San Francisco, teaches only graduate health-sciences students, and the Hastings College of Law, also in San Francisco, is one of UC's four law schools. The UC system is intended to accept students from the top 12.5% of college-bound students, and provide most graduate studies and research. The University of California also administers federal laboratories for the Federal Department of Energy: Lawrence Livermore National Laboratory, Lawrence Berkeley National Laboratory, and Los Alamos National Laboratory.
The California State University system provides education for teachers, the trades, agriculture and industry. With over 400,000 students, the CSU system is the largest university system in the United States. It is intended to accept most college-bound high-school students, while carrying out some research, especially in applied sciences. Lower-division course credits are frequently transferable to the University of California.
The California Community Colleges system provides vocational education, remedial education, and continuing education programs. It awards certificates and associate degrees. It also provides lower division general-education courses, whose credit units are transferable to the CSU and UC systems. It is composed of 109 colleges organized into 72 districts. The system serves a student population of over 2.9 million.
Notable private universities include Stanford University, the University of Southern California (USC), and the California Institute of Technology (Caltech) (which administers the Jet Propulsion Laboratory for NASA).
California has hundreds more private colleges and universities, including many religious and special-purpose institutions. This leads to many unique entertainment and educational opportunities for residents. For example, Southern California, with one of the highest densities of post-secondary institutions in the world, has a very large base of classically trained vocalists that compete in large choir festivals. Near Los Angeles, there are numerous art and film institutes, including the CalArts Institute.
Public secondary education consists of high schools that teach elective courses in trades, languages and liberal arts with tracks for gifted, college-bound and industrial arts students. They accept students from roughly age 14 to 18, with mandatory education ceasing at age 16. In many districts, junior high schools or middle schools teach electives with a strong skills-based curriculum, for ages from 11 to 13. Elementary schools teach pure skills, history and social studies, with optional half-day kindergartens beginning at age 5. Mandatory full-time instruction begins at age 6.
The primary schools are of varying effectiveness. The quality of the local schools depends strongly on the local tax base, and the size of the local administration. In some regions, administrative costs divert a significant amount of educational monies from instructional purposes. In poor regions, literacy rates may fall below 70%. One thing they all have in common is a state mandate to teach fourth grade students about the history of California, including the role of the early missions; most schools implement this by requiring students complete a multiple medium project.
Sports
California's large population has helped to make it home to many professional sports teams, including fifteen major professional sports league franchises, far more than any other state. However, since the re-location of the Los Angeles Raiders and Los Angeles Rams in the 1990s, it could be argued that no one city is able to lay claim to a "Grand Slam" (i.e. having a team in each of the four leagues) unless Oakland, San Francisco and San Jose are counted as being in a single metropolitan area.
Major league teams
Major League Baseball
- Los Angeles Angels of Anaheim
- Los Angeles Dodgers
- Oakland Athletics
- San Diego Padres
- San Francisco Giants
National Basketball Association
- Golden State Warriors
- Los Angeles Clippers
- Los Angeles Lakers
- Sacramento Kings
National Football League
- Oakland Raiders
- San Diego Chargers
- San Francisco 49ers
National Hockey League
- Anaheim Mighty Ducks
- Los Angeles Kings
- San Jose Sharks
Other teams
Arena Football League
- San Jose Sabercats
- Los Angeles Avengers
Major League Soccer
- Club Deportivo Chivas USA
- Los Angeles Galaxy
- San Jose Earthquakes
Women's National Basketball Association
- Los Angeles Sparks
- Sacramento Monarchs
Transportation
Sacramento MonarchsCalifornia's vast terrain is connected by an extensive system of freeways, expressways, and highways, all maintained by Caltrans and patrolled by the California Highway Patrol, except for the numbered expressways in Santa Clara County which were built and maintained by the county itself. Californians typically take to the roads for their commutes, errands, and vacations, giving California's cities a reputation for severe traffic congestion. Almost all California highways are non-toll roads. Notable exceptions are any major bridges.
As for air travel, Los Angeles International Airport and San Francisco International Airport are major hubs for trans-Pacific and transcontinental traffic. There are about a dozen important commercial airports and many more general aviation airports throughout the state's 58 counties.
California also has several important seaports. The giant seaport complex formed by the Port of Los Angeles and the Port of Long Beach in Southern California is the largest in the country and responsible for handling about a fourth of all container cargo traffic in the United States. The Port of Oakland handles most of the ocean containers passing through Northern California.
Port of Oakland ]]
Intercity rail travel is provided by Amtrak. Los Angeles and San Francisco both have subway networks, in addition to
United States of America:For alternative meanings, see the disambiguation page for US, USA, United States, or American.
The United States of America is a federal democratic republic situated primarily in central North America. It comprises 50 states and one federal district, and has several territories. It is also referred to, with varying formality, as the United States, the U.S., the U.S.A., the States, or simply and most commonly, America.
The official founding date of the United States is July 4, 1776, when the Second Continental Congress—representing thirteen British colonies—adopted the Declaration of Independence. However, the structure of the government was profoundly changed in 1788, when the states replaced the Articles of Confederation with the United States Constitution. The date on which each of the fifty states adopted the Constitution is typically regarded as the date that state "entered the Union" (became part of the United States). Since the mid-20th century, following World War II, the United States has emerged as a dominant global influence in economic, political, military, scientific, technological, and cultural affairs.
Geography and climate
The United States shares land borders with Canada (to the north) and Mexico (to the south), and territorial water boundaries with Canada, Russia, the Bahamas, and numerous smaller nations. It is otherwise bounded by the Pacific Ocean and the Bering Sea, in the west; the Arctic Ocean, in the northernmost areas; and the Atlantic Ocean, the Gulf of Mexico, and the Caribbean Sea, in the eastern and southeastern areas.
Forty-eight of the states are in the single region between Canada and Mexico; this group is referred to, with varying precision and formality, as the continental or contiguous United States, sometimes abbreviated CONUS, and as the Lower 48. Alaska, which is not included in the term contiguous United States, is at the northwestern end of North America, separated from the Lower 48 by Canada. The archipelago of Hawaii is in the Pacific Ocean. The capital city, Washington, District of Columbia is a federal district located on land donated by the state of Maryland. (Virginia also donated land, but it was returned in 1847.) The United States also has overseas territories with varying levels of independence and organization.
When inland water is included in the total area, only Russia and Canada are larger than the United States; if inland water is excluded, China ranks third and the U.S. ranks fourth. The United States' total area is 3,718,711 square miles (9,631,418 km²), of which land makes up 3,537,438 square miles (9,161,923 km²) and water makes up 181,273 square miles (469,495 km²).
The United States' landscape is one of the most varied among those of the world's nations: among its many features are temperate forestland and rolling hills, on the east coast; mangrove, in Florida; the Great Plains, in the center of the country; the Mississippi–Missouri river system; the Great Lakes, four of the five of which are shared with Canada; the Rocky Mountains, west of the Great Plains; deserts and temperate coastal zones, west of the Rocky Mountains; and temperate rain forests, in the Pacific northwest. Alaska's tundra, and the volcanic, tropical islands of Hawaii add to the geographic diversity.
Hawaii
The climate varies along with the landscape, from tropical in Hawaii and southern Florida to tundra in Alaska and atop some of the highest mountains. Most of the North and East experience a temperate continental climate, with warm summers and cold winters. Most of the South experiences a subtropical humid climate with mild winters and long, hot, humid summers. Rainfall decreases markedly from the humid forests of the Eastern Great Plains to the semi-arid shortgrass prairies on the high plains abutting the Rocky Mountains. Arid deserts, including the Mojave, extend through the lowlands and valleys of the southwest, from westernmost Texas to California and northward throughout much of Nevada. Some parts of California have a Mediterranean climate. Rainforests line the windward mountains of the Pacific Northwest from Oregon to Alaska.
History
American history started with the migration of people from Asia across the Bering land bridge approximately 12,000 years ago following large animals that they hunted into the Americas. These Native Americans left evidence of their presence in petroglyphs, burial mounds, and other artifacts. It is estimated that 2-9 million people lived in the territory now occupied by the U.S. before European contact, and the subsequent introduction of foreign diseases such as small pox that greatly diminished the native populations. Some advanced societies were the Anasazi of the southwest, who inhabited Chaco Canyon, and the Woodland Indians, who built Cahokia, located near present-day St Louis, a city with a population of 40,000 at its peak in AD 1200.
Vikings first visited North America around 1000, but did not settle permanently. Following the discovery voyages of Christopher Columbus around 1492, other Europeans began to explore and settle there.
During the 1500s and 1600s, the Spanish settled parts of the present-day Southwest and Florida, founding St. Augustine, Florida in 1565 and Santa Fe (in what is now New Mexico) in 1607. The first successful English settlement was at Jamestown, Virginia, also in 1607. Within the next two decades, several Dutch settlements, including New Amsterdam (the predecessor to New York City), were established in what are now the states of New York and New Jersey. In 1637, Sweden established a colony at Fort Christina (in what is now Delaware), but lost the settlement to the Dutch in 1655.
This was followed by extensive British settlement of the east coast. The British colonists remained relatively undisturbed by their home country until after the French and Indian War, when France ceded Canada and the Great Lakes region to Britain. Britain then imposed taxes on the 13 colonies, widely regarded by the colonists as unfair because they were denied representation in the British Parliament. Tensions between Britain and the colonists increased, and the thirteen colonies eventually rebelled against British rule.
British Parliament, George Washington (1789-1797).]]
In 1776, the 13 colonies split from Great Britain and formed the United States, the world's first constitutional and democratic federal republic, after their Declaration of Independence of that year, and the Revolutionary War (1775 to 1783). The original political structure was a confederation in 1777, ratified in 1781 as the Articles of Confederation. After long debate, this was supplanted by the Constitution in 1789, forming a more centralized federal government. Prior to all these was the Albany Congress in 1754, in which a union was first seriously proposed.
From early colonial times, there was a shortage of labor, which encouraged unfree labor, particularly indentured servitude and slavery. In the mid-19th century, a major division occurred in the United States over the issue of states' rights and the expansion of slavery. The northern states had become opposed to slavery, while the southern states saw it as necessary for the continued success of southern agriculture and wanted it expanded to the territories. Several federal laws were passed in an attempt to settle the dispute, including the Missouri Compromise and the Compromise of 1850. The dispute reached a crisis in 1861, when seven southern states seceded1 from the Union and formed the Confederate States of America, leading to the Civil War. Soon after the war began, four more southern states seceded. During the war, Abraham Lincoln issued the Emancipation Proclamation, mandating the freedom of all slaves in states in rebellion, though full emancipation did not take place until after the end of the war in 1865, the dissolution of the Confederacy, and the Thirteenth Amendment took effect. The Civil War effectively ended the question of a state's right to secede, and is widely accepted as a major turning point after which the federal government became more powerful than state governments.
Thirteenth Amendment). The title of the painting, from a 1726 poem by Bishop Berkeley, was a phrase often quoted in the era of Manifest Destiny, expressing a widely held belief that civilization had steadily moved westward throughout history. [http://americanart.si.edu/t2go/1lw/1931.6.1.html (more)] ]]
During the 19th century, many new states were added to the original 13 as the nation expanded across the continent. Manifest Destiny was a philosophy that encouraged westward expansion in the United States. As the population of the Eastern states grew and as a steady increase of immigrants entered the country, settlers moved steadily westward across North America. In the process, the U.S. displaced most American Indian nations. This displacement of American Indians continues to be a matter of contention in the U.S. with many tribes attempting to assert their original claims to various lands. In some areas American Indian populations were reduced by foreign diseases contracted through contact with European settlers, and US settlers acquired those emptied lands. In other instances American Indians were removed from their traditional lands by force. Though some would say the U.S. was not a colonial power until the Spanish-American War when it acquired Puerto Rico, Guam and the Philippines, the dominion exercised over land in North America the United States claimed is essentially colonial. The Philippines became independent in 1946.
During this period, the nation also became an industrial power. This continued into the 20th century, which has been termed "the American Century" because of the nation's overriding influence on the world. The US became a center for innovation and technological development; major technologies that America either developed or was greatly involved in improving include the telephone, television, computer, the Internet, nuclear weapons, nuclear power, aviation, and aeronautics.
In addition to the Civil War, another major traumatic experience for the nation was the Great Depression (1929 to 1939). The nation has also taken part in several major foreign wars, including World War I and World War II (in both of which the US later joined the Allies). During the Cold War, the US was a major player in the Korean War and Vietnam War, and, along with the Soviet Union, was considered one of the world's two "superpowers". With the collapse of the Soviet Union, the US emerged as the world's leading economic and military power. Beginning in the 1990s, the United States became very involved in police actions and peacekeeping, including actions in Kosovo, Haiti, Somalia and Liberia, and the first Persian Gulf War driving Iraq out of Kuwait. After attacks on the World Trade Center and the Pentagon on September 11, 2001, the United States and other allied nations found themselves involved in what has come to be called the "War on Terrorism," which has primarily encompassed military actions in both Afghanistan and Iraq.
Government
Iraq of the United States.]]
Republic and suffrage
The United States is an example of a constitutional republic, with a government composed of and operating through a set of limited powers imposed by its design and enumerated in the United States Constitution. Specifically, the nation operates as a presidential democracy. There are three levels of government: federal, state, and local. Officials of each of these levels are either elected by eligible voters via secret ballot or appointed by other elected officials. Americans enjoy almost universal suffrage from the age of 18 regardless of race, sex, or wealth. There are some limits, however: felons are disenfranchised and in some states former felons are likewise. Furthermore, the national representation of territories and the federal district of Washington, DC in Congress is limited: residents of the District of Columbia are subject to federal laws and federal taxes but their only Congressional representative is a non-voting delegate.
Federal government
The federal government is the national government, comprising the Legislative Branch (led by Congress), the Executive Branch (led by the President), and the Judicial Branch (led by the Supreme Court). These three branches were designed to apply checks and balances on each other. The Constitution limits the powers of the federal government to defense, foreign affairs, the issuing and management of currency, the management of trade and relations between the states, and the protection of human rights. In addition to these explicitly stated powers, the federal government—with the assistance of the Supreme Court—has gradually extended these powers into such areas as welfare and education, on the basis of the "necessary and proper" clause of the Constitution.
The Congress
necessary and proper
The Congress of the United States is the legislative branch of the federal government of the United States. It is bicameral, comprising the House of Representatives and the Senate. The House of Representatives consists of 435 members, each of whom represents a congressional district and serves for a two-year term. House seats are apportioned among the states by population; in contrast, each state has two Senators, regardless of population. There are a total of 100 senators, who serve six-year terms. The powers of Congress are limited to those enumerated in the Constitution; all other powers are reserved to the states and the people. The Constitution also includes the necessary-and-proper clause, which grants Congress the power to "make all laws which shall be necessary and proper for carrying into execution the foregoing powers."
The President
necessary-and-proper clause
At the top level of the executive branch is the President of the United States. The President and Vice-President are elected as 'running mates' for four-year terms by the Electoral College, for which each state, as well as the District of Columbia, is allocated a number of seats based on its representation (or ostensible representation, in the case of D. C.) in both houses of Congress (see U.S. Electoral College). The relationship between the President and the Congress reflects that between the English monarchy and parliament at the time of the framing of the United States Constitution. Congress can legislate to constrain the President's executive power, even with respect to his or her command of the armed forces; however, this power is used only very rarely—a notable example was the constraint placed on President Richard Nixon's strategy of bombing Cambodia during the Vietnam War. The President cannot directly propose legislation, and must rely on supporters in Congress to promote his or her legislative agenda. The President's signature is required to turn congressional bills into law; in this respect, the President has the power—only occasionally used—to veto congressional legislation. Congress can override a presidential veto with a two-thirds majority vote in both houses. The ultimate power of Congress over the President is that of impeachment or removal of the elected President through a House vote, a Senate trial, and a Senate vote. The threat of using this power has had major political ramifications in the cases of Presidents Andrew Johnson, Richard Nixon, and Bill Clinton.
The President makes around 2,000 executive appointments, including members of the Cabinet and ambassadors, which must be approved by the Senate; the President can also issue executive orders and pardons, and has other Constitutional duties, among them the requirement to give a State of the Union address to Congress once a year. Although the President's constitutional role may appear to be constrained, in practice, the office carries enormous prestige that typically eclipses the power of Congress: the Presidency has justifiably been referred to as 'the most powerful office in the world'. The Vice President is first in the line of succession, and is the President of the Senate ex officio, with the ability to cast a tie-breaking vote. The members of the President's Cabinet are responsible for administering the various departments of state, including the Department of Defense, the Justice Department, and the State Department. These departments and department heads have considerable regulatory and political power, and it is they who are responsible for executing federal laws and regulations. George W. Bush is the 43rd President, currently serving his second term.
The Courts
George W. Bush
The highest court is the Supreme Court, which consists of nine justices. The court deals with federal and constitutional matters, and can declare legislation made at any level of the government as unconstitutional, nullifying the law and creating precedent for future law and decisions. Below the Supreme Court are the courts of appeals, and below them in turn are the < | | |
