Natural resource

Natural resource
Natural resources (economically referred to as land or raw materials) occur naturally within environments that exist relata natural form. A natural resource is often characterized by amounts of biodiversity existent in various ecosystems.
Natural resources are derived from the environment. Many of them are essential for our survival while others are used for satisfying our wants. Natural resources may be further classified in different ways.
Classification
On the basis of origin, resources may be divided into:
• Biotic - Biotic resources are obtained from the biosphere, such as forests and their products, animals, birds and their products, fish and other marine organisms. Mineral fuels such as coal and petroleum are also included in this category because they formed from decayed organic matter.
• Abiotic - Abiotic resources comprise of non-living things. Examples include land, water, air and ores such as gold, iron, copper, silver etc.
Considering their stage of development, natural resources may be referred to in the following ways:
• Potential Resources - Potential resources are those that exist in a region and may be used in the future. For example, petroleum may exist in many parts of India, having sedimentary rocks but until the time it is actually drilled out and put into use, it remains a potential resource.
• Actual Resources are those that have been surveyed, their quantity and quality determined and are being used in present times. The development of an actual resource, such as wood processing depends upon the technology available and the cost involved. That part of the actual resource that can be developed profitably with available technology is called a reserve.
With respect to renewability, natural resources can be categorized as follows:
• Renewable resources are ones that can be replenished or reproduced easily. Some of them, like sunlight, air, wind, etc., are continuously available and their quantity is not affected by human consumption. Many renewable resources can be depleted by human use, but may also be replenished, thus maintaining a flow. Some of these, like agricultural crops, take a short time for renewal; others, like water, take a comparatively longer time, while still others, like forests, take even longer.
• Non-renewable resources are formed over very long geological periods. Minerals and fossils are included in this category. Since their rate of formation is extremely slow, they cannot be replenished once they get depleted. Of these, the metallic minerals can be re-used by recycling them. But coal and petroleum cannot be recycled.
[edit] Examples
Some examples of natural resources include the following:
• Agriculture—agronomy is the science and technology of using plants for food, fuel, feed, and fiber.
• Air, wind and atmosphere
• Plants
• Animals
• Coal, fossil fuels, rock and mineral resources
• Forestry
• Range and pasture
• Soils
• Water, ponds, oceans, lakes, groundwater and rivers [2]
[edit] Management
Main article: Natural resource management
Natural resource management is a discipline in the management of natural resources such as land, water, soil, plants and animals, with a particular focus on how management affects the quality of life for both present and future generations. Natural resource management is interrelated with the concept of sustainable development, a principle that forms a basis for land management and environmental governance throughout the world.
In contrast to the policy emphases of urban planning and the broader concept of environmental management, Natural resource management specifically focuses on a scientific and technical understanding of resources and ecology and the life-supporting capacity of those resources.
[edit] Depletion
In recent years, the depletion of natural resources and attempts to move to sustainable development have been a major focus of development agencies. This is of particular concern in rainforest regions, which hold most of the Earth's natural biodiversity - irreplaceable genetic natural capital. Conservation of natural resources is the major focus of natural capitalism, environmentalism, the ecology movement, and green politics. Some view this depletion as a major source of social unrest and conflicts in developing nations.
Mining, petroleum extraction, fishing, hunting, and forestry are generally considered natural-resource industries. Agriculture is considered a man-made resource. Theodore Roosevelt, a well-known conservationist and former United States president, was opposed to unregulated natural resource extraction. The term is defined by the United States Geological Survey as "The Nation's natural resources include its minerals, energy, land, water, and biota."[3]
[edit] Protection
See also: Environmental protection
Conservation biology is the scientific study of the nature and status of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction.[4][5] It is an interdisciplinary subject drawing on sciences, economics, and the practice of natural resource management.[6][7][8][9] The term conservation biology was introduced as the title of a conference held University of California at San Diego in La Jolla, California in 1978 organized by biologists Bruce Wilcox and Michael Soulé.

Natural disaster

Natural disaster
A natural disaster is the effect of a natural hazard (e.g. flood,(tornado) volcano eruption, earthquake, or landslide) that affects the environment, and leads to financial, environmental and/or human losses. The resulting loss depends on the capacity of the population to support or resist the disaster, and their resilience. This understanding is concentrated in the formulation: "disasters occur when hazards meet vulnerability." A natural hazard will hence never result in a natural disaster in areas without vulnerability, e.g. strong earthquakes in uninhabited areas. The term natural has consequently been disputed because the events simply are not hazards or disasters without human involvement.
Contents
• 1 Natural hazards
• 2 Natural disasters
o 2.1 Land movement disasters
 2.1.1 Avalanches
 2.1.2 Earthquakes
 2.1.3 Lahars
 2.1.4 Landslides and Mudflows
 2.1.5 Volcanic eruptions
o 2.2 Water disasters
 2.2.1 Floods
 2.2.2 Limnic eruptions
 2.2.3 Tsunamis
o 2.3 Weather disasters
 2.3.1 Blizzards
 2.3.2 Cyclonic storms
 2.3.3 Droughts
 2.3.4 Hailstorms
 2.3.5 Heat waves
 2.3.6 Tornadoes
o 2.4 Fire
o 2.5 Health and diseases
 2.5.1 Epidemic
 2.5.2 Famine
o 2.6 Space
 2.6.1 Gamma ray bursts
 2.6.2 Impact events
 2.6.3 Solar flares
 2.6.4 Supernovae and hypernovae
• 3 Future of natural disasters
• 4 Insurance

Natural hazards
A natural hazard is a threat of an event that will have a negative effect on people or the environment. Many natural hazards are related, e.g. earthquakes can result in tsunamis, drought can lead directly to famine and disease. A concrete example of the division between hazard and disaster is that the 1906 San Francisco earthquake was a disaster, whereas earthquakes are a hazard. Hazards are consequently relating to a future occurrence and disasters to past or current occurrences.
Natural disasters
Land movement disasters
Avalanches

Avalanche on the backside (East) of Mt. Timpanogos, Utah at Aspen Grove trail
Notable avalanches include:
• The 1910 Wellington avalanche
• The 1954 Blons avalanches
• The 1970 Ancash earthquake
• The 1999 Galtür Avalanche
• The 2002 Kolka-Karmadon rock ice slide
Earthquakes
An Earthquake is a sudden shake of the Earth's crust.The vibrations may vary in magnitude. The earthquake has point of origin underground called the "focus". The point directly above the focus on the surface is called the"epicentre". Earthquakes by themselves rarely kill people or wildlife. It is usually the secondary events that they trigger, such as building collapse, fires, tsunamis (seismic sea waves) and volcanoes, that are actually the human disaster. As many of these could be avoided by better construction, safety systems, early warning and evacuation planning, the term unnatural disaster is not unwarranted.
Earthquakes are caused by the discharge of accumulated along geologic faults.
Some of the most significant earthquakes in recent times include:
• The 2004 Indian Ocean earthquake, the second largest earthquake in recorded history, registering a moment magnitude of 9.3. The huge tsunamis triggered by this earthquake cost the lives of at least 229,000 people.
• The 7.6-7.7 2005 Kashmir earthquake, which cost 79,000 lives in Pakistan.
• The 7.7 magnitude July 2006 Java earthquake, which also triggered tsunamis.

A Sumatran village, devastated by the tsunami that followed the 2004 Indian Ocean earthquake
• The 7.9 magnitude May 12, 2008 Sichuan earthquake in Sichuan Province, China. Death toll at over 61,150 as of May 27, 2008.
Lahars
A lahar is a volcanic mudflow or landslide. The 1953 Tangiwai disaster was caused by a lahar, as was the 1985 Armero tragedy in which the town of Armero was buried and an estimated 23,000 people were killed
Landslides and Mudflows
These occur with some regularity in parts of California after periods of heavy rain.
Volcanic eruptions

Pu'u 'Ō'ō
• An Eruption may in itself be a disaster due to the explosion of the volcano or the fall of rock but there are several effects that may happen after an eruption that are also hazardous to human life.
• Lava may be produced during the eruption of a volcano a material consisting of superheated rock. There are several different forms which may be either crumbly or gluey. Leaving the volcano this destroys any buildings and plants it encounters.
• Volcanic ash - generally meaning the cooled ash - may form a cloud, and settle thickly in nearby locations. When mixed with water this forms a concrete like material. In sufficient quantity ash may cause roofs to collapse under its weight but even small quantities will cause ill health if inhaled. Since the ash has the consistency of ground glass it causes abrasion damage to moving parts such as engines.
• Supervolcanos : According to the Toba catastrophe theory 70 to 75 thousand years ago a super volcanic event at Lake Toba reduced the human population to 10,000 or even 1,000 breeding pairs creating a bottleneck in human evolution. It also killed three quarters of all plant life in the northern hemisphere. The main danger from a supervolcano is the immense cloud of ash which has a disastrous global effect on climate and temperature for many years.
• Pyroclastic flows consist of a cloud of hot volcanic ash which builds up in the air above under its own weight and streams very rapidly from the mountain burning anything in its path. It is believed that Pompeii was destroyed by a pyroclastic flow.
Water disasters
Floods

The Limpopo River, in southern Mozambique, during the 2000 Mozambique flood
Some of the most notable floods include:
• The Huang He (Yellow River) in China floods particularly often. The Great Flood of 1931 caused between 800,000 and 4,000,000 deaths.
• The Great Flood of 1993 was one of the most costly floods in United States history.
• The 1998 Yangtze River Floods, also in China, left 14 million people homeless.
• The 2000 Mozambique flood covered much of the country for three weeks, resulting in thousands of deaths, and leaving the country devastated for years afterward.
Tropical cyclones can result in extensive flooding and storm surge, as happened with:
• Bhola Cyclone, striking East Pakistan (now Bangladesh) in 1970,
• Typhoon Nina, striking China in 1975,
• Tropical Storm Allison, which struck Houston, Texas in 2001 and
• Hurricane Katrina, which left most of New Orleans under water in 2005. Much of the flooding was due to the failure of the city's levee system.
Limnic eruptions

A cow suffocated by gases from Lake Nyos after a limnic eruption
A limnic eruption occurs when CO2 suddenly erupts from deep lake water, posing the threat of suffocating wildlife, livestock and humans. Such an eruption may also cause tsunamis in the lake as the rising CO2 displaces water. Scientists believe landslides, volcanic activity, or explosions can trigger such an eruption.Till date, only two limnic eruptions have been observed and recorded:
• In 1984, in Cameroon, a limnic eruption in Lake Monoun caused the deaths of 37 nearby residents
• At nearby Lake Nyos in 1986 a much larger eruption killed between 1,700 and 1,800 people by asphyxiation.
Tsunamis

The tsunami caused by the December 26, 2004 earthquake strikes Ao Nang, Thailand.
Tsunamis can be caused by undersea earthquakes as the one caused in Ao Nang, Thailand by the 2004 Indian Ocean Earthquake, or by landslides such as the one which occurred at Lituya Bay, Alaska in.
• Ao Nang, Thailand (2004). The 2004 Indian Ocean Earthquake created the Boxing Day Tsunami and disaster at this site.
• Lituya Bay, Alaska (1953). A mega-tsunami occurred here, the largest ever recorded.
• This would also fit within Land movement category because it starts with an earthquake.


Weather disasters

Young steer after a blizzard, March 1966
Blizzards
Significant blizzards in the United States include:
• The Great Blizzard of 1888
• The Schoolhouse Blizzard earlier the same year
• The Armistice Day Blizzard in 1940
• The Storm of the Century in 1993
Cyclonic storms
Cyclone, tropical cyclone, hurricane, and typhoon are different names for the same phenomenon a cyclonic storm system that forms over the oceans. The deadliest hurricane ever was the 1970 Bhola cyclone the deadliest Atlantic hurricane was the Great Hurricane of 1780 which devastated Martinique St. Eustatius and Barbados. Another notable hurricane is Hurricane Katrina which devastated the Gulf Coast of the United States in 2005.
Droughts
Well-known historical droughts include:
• 1900 India killing between 250,000 and 3.25 million.
• 1921-22 Soviet Union in which over 5 million perished from starvation due to drought
• 1928-30 northwest China resulting in over 3 million deaths by famine.
• 1936 and 1941 Sichuan Province China resulting in 5 million and 2.5 million deaths respectively.
• As of 2006 Western Australia New South Wales Victoria Australia Victoria and Queensland states of Australia have been under drought conditions for five to ten years. The drought is beginning to affect urban area populations for the first time.
• In 2006 Sichuan Province China experienced its worst drought in modern times with nearly 8 million people and over 7 million cattle facing water shortages.
Hailstorms
Hailstorms (AKA hailstones) are rain drops that have formed together into ice. A particularly damaging hailstorm hit Munich, Germany on August 31, 1986, felling thousands of trees and causing millions of dollars in insurance claims.
Heat waves
The worst heat wave in recent history was the European Heat Wave of 2003.

Hurricane Katrina
The heat wave in Victoria Australia caused the massive bushfires in 2009, Melbourne experienced 3 days in a row of temperatures exceeding 43°C.
Tornadoes
Different Types of Tornadoes
Supercell Tornadoes
Some of the most violent tornadoes develop from supercell thunderstorms. A supercell thunderstorm is a long-lived thunderstorm possessing within its structure a continuously rotating updraft of air. These storms have the greatest tendency to produce tornadoes, some of the huge wedge shape. The supercell thunderstorm has a low-hanging, rotating layer of cloud known as a “wall cloud.” It looks somewhat like a layer of a layer cake that hangs below the broader cloud base. One side of the wall cloud is often rain-free, while the other is neighbored by dense shafts of rain. The rotating updraft of the supercell is seen on radar as a “mesocyclone.”
The tornadoes that accompany supercell thunderstorms are more likely to remain in contact with the ground for long periods of time -- an hour or more -- than other tornadoes, and are more likely to be violent, with winds exceeding 200 mph.
Landspout
Generally weaker than a supercell tornado, a landspout is not associated with a wall cloud or mesocyclone. It may be observed beneath cumulonimbus or towering cumulus clouds and is the land equivalent of a waterspout. It often forms along the leading edge of rain-cooled downdraft air emanating from a thunderstorm, known as a “gust front.”
Gustnado
Weak and usually short-lived, a gustnado forms along the gust front of a thunderstorm, appearing as a temporary dust whirl or debris cloud. There may be no apparent connection to or circulation in the cloud aloft. These appear like dust devils.
Waterspout
A waterspout is a tornado over water. A few form from supercell thunderstorms, but many form from weak thunderstorms or rapidly growing cumulus clouds. Waterspouts are usually less intense and causes far less damage. Rarely more than fifty yards wide, it forms over warm tropical ocean waters, although its funnel is made of freshwater droplets condensed from water vapor from condensation - not saltwater from the ocean. Waterspouts usually dissipate upon reaching land.
The following are tornado-like circulations
Dust Devils
Dry, hot, clear days on the desert or over dry land can bring about dust devils. Generally forming in the hot sun during the late morning or early afternoon hours, these mostly harmless whirlwinds are triggered by light desert breezes that create a swirling plume of dust with speeds rarely over 70 mph. These differ from tornadoes in that they are not associated with a thunderstorm (or any cloud), and are usually weaker than the weakest tornado.
Typically, the life cycle of a dust devil is a few minutes or less, although they can last much longer. Although usually harmless, they have been known to cause minor damage. They can blow vehicles off the road and could damage your eyes by blowing dust into them.
Firewhirls
Sometimes the intense heat created by a major forest fire or volcanic eruption can create what is known as a firewhirl, a tornado-like rotating column of smoke and/or fire. This happens when the fire updraft concentrates some initial weak whirl or eddy in the wind. Winds associated with firewhirls have been estimated at over 100 mph. They are sometimes called fire tornadoes, fire devils, or even firenadoes.
Fire
Wildfires are an uncontrolled fire burning in wildland areas. Common causes include lightning and drought but wildfires may also be started by human negligence or arson. They can be a threat to those in rural areas and also wildlife.
A notable case of wildfire was the 2009 Victorian bushfires in Australia.
Health and diseases
Epidemic

The A H5N1 virus, which causes Avian influenza
An epidemic is an outbreak of a contractible disease that spreads at a rapid rate through a human population. A pandemic is an epidemic whose spread is global. There have been many epidemics throughout history, such as Black Death. In the last hundred years, significant pandemics include:
• The 1918 Spanish flu pandemic, killing an estimated 50 million people worldwide
• The 1957-58 Asian flu pandemic, which killed an estimated 1 million people
• The 1968-69 Hong Kong flu pandemic
• The 2002-3 SARS pandemic
• The AIDS epidemic, beginning in 1959
• The H1N1 Influenza (Swine Flu) Pandemic 2009-?
Other diseases that spread more slowly, but are still considered to be global health emergencies by the WHO include:
• XDR TB, a strain of tuberculosis that is extensively resistant to drug treatments
• Malaria, which kills an estimated 1.5 million people each year
• Ebola hemorrhagic fever, which has claimed hundreds of victims in Africa in several outbreaks
Famine
In modern times, famine has hit Sub-Saharan Africa the hardest, although the number of victims of modern famines is much smaller than the number of people killed by the Asian famines of the 20th century.
Space

Fallen trees caused by the Tunguska meteoroid of the Tunguska event in June, 1908.
Gamma ray bursts
Impact events
One of the largest impact events in modern times was the Tunguska event in June, 1908.
Solar flares
A solar flare is a phenomenon where the sun suddenly releases a great amount of solar radiation, much more than normal. Some known solar flares include:
• An X20 event on August 16, 1989
• A similar flare on April 2, 2001
• The most powerful flare ever recorded, on November 4, 2003, estimated at between X40 and X45
• The most powerful flare in the past 500 years is believed to have occurred in September 1859
Supernovae and hypernovae
Future of natural disasters
The United Kingdom based charity Oxfam publicly stated that the number of people hit by climate-related disasters is expected to rise by about 50%, to reach 375 million a year by 2015.
Insurance
Natural disasters play a major role in the insurance industry, which pays for certain damages arising from hurricanes, wildfires, and other catastrophes. Large reinsurance companies are particularly involved.

Laws of Cricket

Laws of cricket
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The laws of cricket are a set of rules framed by the Marylebone Cricket Club (MCC) which serve to standardise the format of cricket matches across the world to ensure uniformity and fairness. There are currently 42 laws, which outline all aspects of how the game is played from how a team wins a game, how a batsman is dismissed, through to specifications on how the pitch is to be prepared and maintained. Although the MCC is a private club based in London and no longer the game's governing body, the MCC retains copyright in the laws and only the MCC may change the laws, although nowadays this would usually only be done after discussions with the game's global governing body the International Cricket Council.
Cricket is one of the few sports for which the governing principles are referred to as 'Laws' rather than as 'Rules' or 'Regulations'. However regulations to supplement and/or vary the laws may be agreed for particular competitions.
Contents
[hide]
• 1 History
• 2 Today's laws
o 2.1 Players and officials
o 2.2 Equipment and laying out the pitch
o 2.3 Structure of the game
o 2.4 Scoring and winning
o 2.5 Mechanics of dismissal
o 2.6 Ways to get out
o 2.7 Fielders
o 2.8 Fair and unfair play
o 2.9 Appendices
• 3 See also
• 4 References
• 5 External links

[edit] History
Cricket started out as a game played by children, but expanded to become a betting game, and where rich aristocrats were involved, the wagers could be large. The earliest laws were drawn up in that context, to help regulate a game on which large sums of money were being staked. The earliest existing known Code of cricket was drawn up by certain "Noblemen and Gentlemen" who used the Artillery Ground in London in 1744. In 1755 there is further reference to the laws being revised by "Several Cricket Clubs, particularly the Star and Garter in Pall Mall", followed by a revision of the Laws by "a Committee of Noblemen and Gentlemen of Kent, Hampshire, Surrey, Sussex, Middlesex and London at the Star and Garter" in 1774. A printed form of the laws was published in 1775 and a further revision to the laws was undertaken by a similar body of Noblemen and Gentlemen of Kent, Hampshire, Surrey, Sussex, Middlesex and London in 1786.
However, these laws were not universally followed, with different games played under different guidance. On 30 May 1788, the Marylebone Cricket Club, which had been formed by the leading noblemen and gentlemen playing the game just one year before, produced its first Code of Laws. Whilst the MCC's version of the Laws were not accepted fully immediately, or applied consistently, it is the successor of these Laws that governs the game today. The next major change was in 1809 and saw the further standardisation of the weight of the ball from between 5 and 6 ounces (142 to 170 g) to between 5.5 and 5.75 ounces (156 to 163 g), and the width of the cricket bat was standardised for the first time. The length of stumps was increased from 22 to 24 inches and bails from 6 to 7 inches to help the bowlers, and the importance of umpires was further enhanced. Finally, a new method of dismissing a batsman was introduced. Previously, as cricket uses a hard ball and leg-pads were not used, players would naturally play with their legs away from the wicket. As batsmen started to wear pads, they became willing to cover their stumps with their legs to prevent the ball hitting the stumps and bowling them. Therefore a "leg before wicket" rule was introduced so that a batsman preventing the ball hitting his stumps with his legs would be out.
In 1829 the Length of stumps increased from 24 to 27 inches (610 to 690 mm) and the length of the bails was increased from 7 to 8 inches (180 to 200 mm), again to help the bowlers. For the first time, the thickness of stumps was mentioned. A new Code of Laws was approved by the MCC Committee on 19 May 1835, and another on 21 April 1884. In the 1884 laws the number of players was formalised for the first time (at eleven-a-side), and the size of the ball was formalised for the first time too. The follow-on rule was introduced. This was in response to the problem that to win a game a side needed to dismiss their opposition twice. A side that batted first and was fully on top of a match and scoring lots of runs would have to wait until it was dismissed a second time before it could attempt to dismiss the opposition a second time. As cricket is a time-limited game, it meant that sides that dominated the opposition could be forced to draw rather than win games. The initial follow-on rule was faulty, though, as it required a side to follow-on when it was behind. A side could deliberately concede its last wickets in the first innings in return for being able to bowl last on a deteriorating pitch. Later the follow-on rule was changed so that a team sufficiently ahead of its opposition has the option on whether to enforce it or not.
In 1947 a new Code was approved by the MCC on 7 May. In 1979 after a number of minor revisions of the 1947 Code, a new Code was approved at an MCC Special General Meeting on 21 November. This is known as the 1980 code. Amongst other changes, imperial units are now followed by metric units in the specifications.
In 1992 a second edition of the 1980 Code was produced. In 2000 a new Code, which for the first time included a Preamble defining the Spirit of Cricket was approved on 3 May. The code was rewritten into plain English and is more discursive than previous Codes. The length of an over was officially standardised at six balls for all matches, although in practice this had been the case for 20 or so years before that. In 2003 a second version of the 2000 Code was produced incorporating necessary amendments arising from the application of the 2000 Code.
Throwing was first regulated in laws produced in 1829. In 1864 overarm bowling was permitted for the first time.
In 1889, the length of an over increased from four balls to five balls. In 1900, the length of an over was increased to six balls. In 1922, variation was allowed in the length of the over (Australian overs to be eight balls). The 1947 Code stipulated that the length of an over was to be six or eight balls according to "prior agreement" between the captains.
[edit] Today's laws
The Marylebone Cricket Club is the framer of the Laws of Cricket, the rules governing play of the game. The Laws are intended to apply to all two innings matches; the International Cricket Council has implemented "Standard Playing Conditions for Test Matches" and "Standard Playing Conditions for One Day Internationals" to augment the Laws of Cricket. Similarly, each cricketing country has implemented Playing Conditions to govern domestic cricket. The Laws provide for One-day, or Limited overs cricket (including Twenty20) by stipulating that the number of innings per side may be one or two, and that each innings may be restricted to a maximum number of overs, or a maximum period of time.
The Laws retain the Imperial units as they were originally specified, but now also include metric conversions.
The Laws are organised into a Preface, a Preamble, forty-two Laws, and four appendices. The Preface relates to the Marylebone Cricket Club and the history of the Laws. The Preamble is a new addition and is related to "the Spirit of the Game;" it was introduced to discourage the increasing practices of ungentlemanly conduct. The Laws themselves deal with the following:
[edit] Players and officials


In men's cricket the ball must weigh between 5.5 and 5.75 ounces (155.9 and 163 g) and measure between 8 13/16 and 9 in (22.4 and 22.9 cm) in circumference.


The Cricket pitch dimensions


A wicket consists of three stumps, upright wooden poles that are hammered into the ground, topped with two wooden crosspieces, known as the bails.

The first four laws cover the players, the umpires and the scorers.
• Law 1: The players. A cricket team consists of eleven players, including a captain. Outside of official competitions, teams can agree to play more than eleven-a-side, though no more than eleven players may field.
• Law 2: Substitutes. In cricket, a substitute may be brought on for an injured fielder. However, a substitute may not bat, bowl, keep wicket or act as captain. The original player may return if he has recovered. A batsman who becomes unable to run may have a runner, who completes the runs while the batsman continues batting. Alternatively, a batsman may retire hurt or ill, and may return later to resume his innings if he recovers.
• Law 3: The umpires. There are two umpires, who apply the Laws, make all necessary decisions, and relay the decisions to the scorers. While not required under the laws of cricket, in higher level cricket a third umpire (located off the ground and available to assist the on-field umpires) may be used under the specific playing conditions of a particular match or tournament.
• Law 4: The scorers. There are two scorers who respond to the umpires' signals and keep the score.
[edit] Equipment and laying out the pitch
After dealing with the players, the laws move on to discuss equipment and pitch specifications, except for specifications about the wicket-keeper's gloves, which are dealt with in Law 40. These laws are supplemented by Appendices A and B (see below).
• Law 5: The ball. A cricket ball is between 8 13/16 and 9 inches (22.4 cm and 22.9 cm) in circumference, and weighs between 5.5 and 5.75 ounces (155.9g and 163g). Only one ball is used at a time, unless it is lost, when it is replaced with a ball of similar wear. It is also replaced at the start of each innings, and may, at the request of the fielding side, be replaced with a new ball, after a certain number of overs have been bowled (80 in Test matches, 34 in ODIs). The gradual degradation of the ball through the innings is an important aspect of the game.
• Law 6: The bat. The bat is no more than 38 inches (97 cm) in length, and no more than 4.25 inches (10.8 cm) wide. The hand or glove holding the bat is considered part of the bat. Ever since the Heavy Metal incident, a highly publicized marketing attempt by Dennis Lillee, who brought out an aluminium bat during an international game, the laws have provided that the blade of the bat must be made of wood (and in practice, they are made from White Willow wood).
• Law 7: The pitch. The pitch is a rectangular area of the ground 22 yards (20 m) long and 10 ft (3.0 m) wide. The Ground Authority selects and prepares the pitch, but once the game has started, the umpires control what happens to the pitch. The umpires are also the arbiters of whether the pitch is fit for play, and if they deem it unfit, with the consent of both captains can change the pitch. Professional cricket is almost always played on a grass surface. However, in the event a non-turf pitch is used, the artificial surface must have a minimum length of 58 ft (18 m) and a minimum width of 6 ft (1.8 m).
• Law 8: The wickets. The wicket consists of three wooden stumps that are 28 inches (71 cm) tall. The stumps are placed along the batting crease with equal distances between each stump. They are positioned so they are 9 inches (23 cm) wide. Two wooden bails are placed on top of the stumps. The bails must not project more than 0.5 inches (1.3 cm) above the stumps, and must, for men's cricket, be 45⁄16 inches (10.95 cm) long. There are also specified lengths for the barrel and spigots of the bail. There are different specifications for the wickets and bails for junior cricket. The umpires may dispense with the bails if conditions are unfit (ie it is windy so they might fall off by themselves). Further details on the specifications of the wickets are contained in Appendix A to the laws.
• Law 9: Bowling, popping, and return creases. This law sets out the dimensions and locations of the creases. The bowling crease, which is the line the stumps are in the middle of, is drawn at each end of the pitch so that the three stumps in the set of stumps at that end of the pitch fall on it (and consequently it is perpendicular to the imaginary line joining the centres of both middle stumps). Each bowling crease should be 8 feet 8 inches (2.64 m) in length, centred on the middle stump at each end, and each bowling crease terminates at one of the return creases. The popping crease, which determines whether a batsman is in his ground or not, and which is used in determining front-foot no balls (see law 24), is drawn at each end of the pitch in front of each of the two sets of stumps. The popping crease must be 4 feet (1.2 m) in front of and parallel to the bowling crease. Although it is considered to have unlimited length, the popping crease must be marked to at least 6 feet (1.8 m) on either side of the imaginary line joining the centres of the middle stumps. The return creases, which are the lines a bowler must be within when making a delivery, are drawn on each side of each set of the stumps, along each sides of the pitch (so there are four return creases in all, one on either side of both sets of stumps). The return creases lie perpendicular to the popping crease and the bowling crease, 4 feet 4 inches (1.32 m) either side of and parallel to the imaginary line joining the centres of the two middle stumps. Each return crease terminates at one end at the popping crease but the other end is considered to be unlimited in length and must be marked to a minimum of 8 feet (2.4 m) from the popping crease.
• Law 10: Preparation and maintenance of the playing area. In cricket, when a ball is bowled it almost always bounces on the pitch, and how the ball behaves depends very much on the condition of the pitch. Therefore detailed rules on the pitch itself are necessary. This law sets down rules governing how pitches should be prepared, mown, rolled, etc.
• Law 11: Covering the pitch. Covering the pitch affects how the ball will react when it bounces on it. For example, a ball bouncing on wet ground will react differently to one bouncing on hard ground. In general, a wet pitch will have uneven bounce, a dry pitch won't. The laws stipulate that the regulations on covering the pitch shall be agreed in advance. Bowlers' run-ups also need to be dry to reduce the chances that they will slip. The laws therefore require these to be covered wherever possible when there is wet weather.
[edit] Structure of the game
Laws 12 to 17 outline the structure of the game.
• Law 12: Innings. Before the game, the teams agree whether it is to be over one or two innings, and whether either or both innings are to be limited by time or by overs. In practice, these decisions are likely to be laid down by Competition Regulations, rather than pre-game agreement. In two-innings games, the sides bat alternately unless the follow-on (law 13) is enforced. An innings is closed once all batsmen are dismissed, no further batsmen are fit to play, the innings is declared or forfeited by the batting captain, or any agreed time or over limit is reached. The captain winning the toss of a coin decides whether to bat or to bowl first.
• Law 13: The follow-on. In a two innings match, if the side batting second scores substantially fewer runs than the side batting first, the side that batted first can force their opponents to bat again immediately. The side that enforced the follow-on risks not getting to bat again and thus the chance of winning. For a game of five or more days, the side batting first must be at least 200 runs ahead to enforce the follow-on; for a three- or four-day game, 150 runs; for a two-day game, 100 runs; for a one-day game, 75 runs. The length of the game is determined by the number of scheduled days play left when the game actually begins.
• Law 14: Declaration and forfeiture. The batting captain can declare an innings closed at any time when the ball is dead. He may also forfeit his innings before it has started.
• Law 15: Intervals. There are intervals between each day's play, a ten-minute interval between innings, and lunch, tea and drinks intervals. The timing and length of the intervals must be agreed before the match begins. There are also provisions for moving the intervals and interval lengths in certain situations, most notably the provision that if nine wickets are down, the tea interval is delayed to the earlier of the fall of the next wicket and 30 minutes elapsing.
• Law 16: Start of play; cessation of play. Play after an interval commences with the umpire's call of "Play", and at the end of a session by "Time". The last hour of a match must contain at least 20 overs, being extended in time so as to include 20 overs if necessary.
• Law 17: Practice on the field. There may be no batting or bowling practice on the pitch except before the day's play starts and after the day's play has ended. Bowlers may only have trial run-ups if the umpires are of the view that it would waste no time.
[edit] Scoring and winning
The laws then move on to discuss how runs can be scored and how one team can beat the other.
• Law 18: Scoring runs. Runs are scored when the two batsmen run to each other's end of the pitch. Several runs can be scored from one ball.
• Law 19: Boundaries. A boundary is marked round the edge of the field of play. If the ball is hit past this boundary, four runs are scored, or six runs if the ball didn't hit the ground before crossing the boundary.
• Law 20: Lost ball. If a ball in play is lost or cannot be recovered, the fielding side can call "lost ball". The batting side keeps any penalty runs (such as no-balls and wides) and scores the higher of six runs and the number of runs actually run.
• Law 21: The result. The side which scores the most runs wins the match. If both sides score the same number of runs, the match is tied. However, the match may run out of time before the innings have all been completed. In this case, the match is drawn.
• Law 22: The over. An over consists of six balls bowled, excluding wides and no balls. Consecutive overs are delivered from opposite ends of the pitch. A bowler may not bowl two consecutive overs.
• Law 23: Dead ball. The ball comes into play when the bowler begins his run up, and becomes dead when all the action from that ball is over. While the ball is dead, no runs can be scored and no batsmen can be dismissed. The ball also becomes dead when a batsman is dismissed.
• Law 24: No ball. A ball can be a no ball for several reasons: if the bowler bowls from the wrong place; or if he straightens his elbow during the delivery; or if the bowling is dangerous; or if the ball bounces more than twice or rolls along the ground before reaching the batsman; or if the fielders are standing in illegal places. A no ball adds one run to the batting team's score, in addition to any other runs which are scored off it, and the batsman can't be dismissed off a no ball except by being run out, or by handling the ball, hitting the ball twice, or obstructing the field.
• Law 25: Wide ball. An umpire calls a ball "wide" if, in his or her opinion, the batsman did not have a reasonable opportunity to score off the ball. A ball is called wide when the bowler bowls a bouncer that goes over the head of the batsman. A wide adds one run to the batting team's score, in addition to any other runs which are scored off it, and the batsman can't be dismissed off a wide except by being run out or stumped, or by handling the ball, hitting his wicket, or obstructing the field.
• Law 26: Bye and Leg bye. If a ball that isn't a no ball or wide passes the striker and runs are scored, they are called byes. If a ball that isn't a no ball hits the striker but not the bat and runs are scored, they are called leg-byes. However, leg-byes cannot be scored if the striker is neither attempting a stroke nor trying to avoid being hit. Byes and leg-byes are credited to the team's but not the batsman's total.
[edit] Mechanics of dismissal
Laws 27 to 29 discuss the main mechanics of how a batsman may be dismissed.
• Law 27: Appeals. If the fielders believe a batsman is out, they may ask the umpire "How's That?", commonly shouted emphatically with arms raised, before the next ball is bowled. The umpire then decides whether the batsman is out.
• Law 28: The wicket is down. Several methods of being out occur when the wicket is put down. This means that the wicket is hit by the ball, or the batsman, or the hand in which a fielder is holding the ball, and at least one bail is removed.
• Law 29: Batsman out of his ground. The batsmen can be run out or stumped if they are out of their ground. A batsman is in his ground if any part of him or his bat is on the ground behind the popping crease. If both batsman are in the middle of the pitch when a wicket is put down, the batsman closer to that end is out.
[edit] Ways to get out
Laws 30 to 39 discuss the various ways a batsman may be dismissed. In addition to these 10 methods, a batsman may retire out. That provision is in Law 2.
• Law 30: Bowled. A batsman is out if his wicket is put down by a ball delivered by the bowler. It is irrelevant whether the ball has touched the bat, glove, or any part of the batsman before going on to put down the wicket, though it may not touch another player or an umpire before doing so.
• Law 31: Timed out. An incoming batsman must be ready to face a ball (or be at the crease with his partner ready to face a ball) within 2 minutes of the outgoing batsman being dismissed, otherwise the incoming batsman will be out.
• Law 32: Caught. If a ball hits the bat or the hand holding the bat and is then caught by the opposition within the field of play before the ball bounces, then the batsman is out.
• Law 33: Handled the ball. If a batsman willfully handles the ball with a hand that is not touching the bat without the consent of the opposition, he is out.
• Law 34: Hit the ball twice. If a batsman hits the ball twice, other than for the sole purpose of protecting his wicket or with the consent of the opposition, he is out.
• Law 35: Hit wicket. If, after the bowler has entered his delivery stride and while the ball is in play, a batsman puts his wicket down by his bat or his person he is out. The striker is also out hit wicket if he puts his wicket down by his bat or his person in setting off for a first run. "Person" includes the clothes and equipment of the batsman.
• Law 36: Leg before wicket (LBW). If the ball hits the batsman without first hitting the bat, but would have hit the wicket if the batsman was not there, and the ball does not pitch on the leg side of the wicket the batsman will be out. However, if the ball strikes the batsman outside the line of the off-stump, and the batsman was attempting to play a stroke, he is not out.
• Law 37: Obstructing the field. If a batsman wilfully obstructs the opposition by word or action, he is out.
• Law 38: Run out. A batsman is out if at any time while the ball is in play no part of his bat or person is grounded behind the popping crease and his wicket is fairly put down by the opposing side.
• Law 38(a):If runner batsman is out of the crease, before bowler delivers the ball, then bowler can hit the ball to the corrosponding stumps before delivering it, and can appeal for out. (no longer in effect)
• Law 39: Stumped. A batsman is out when the wicket-keeper (see Law 40) puts down the wicket, while the batsman is out of his crease and not attempting a run
[edit] Fielders
• Law 40: The wicket-keeper
• Law 41: The fielder
[edit] Fair and unfair play
• Law 42: Fair and unfair play
[edit] Appendices
The five appendices to the laws, are as follows:
• Appendix A: Specifications and diagrams of stumps and bails
• Appendix B: Specifications and diagrams of the pitch and creases
• Appendix C: Specifications and diagrams of gloves
• Appendix D: Definitions
• Appendix E: The bat

Islam

Islam

This article contains Arabic text, written from right to left in a cursive style with some letters joined. Without proper rendering support, you may see unjoined Arabic letters written left-to-right instead of right-to-left or other symbols instead of Arabic script.


A Muslim prays during the Hajj pilgrimage at Mecca
Part of a series on

Islam
Beliefs

Allah • Oneness of God
Muhammad • Other prophets

Practices

Profession of faith • Prayer
Fasting • Charity • Pilgrimage

Texts and laws

Qur'an • Sunnah • Hadith
Fiqh • Sharia • Kalam • Sufism

History and leadership

Timeline • Spread of Islam
Ahl al-Bayt • Sahaba
Sunni • Shi'a
Rashidun • Caliphate
Imamate

Culture and society

Academics • Animals • Art
Calendar • Children
Demographics • Festivals
Mosques • Philosophy
Science • Women
Politics • Dawah

Islam and other religions

Christianity • Judaism
Hinduism • Sikhism • Jainism

See also

Criticism • Islamophobia
Glossary of Islamic terms

Islam portal
v • d • e


Islam (Arabic: الإسلام‎ al-’islām) is the religion articulated by the Qur’an, a book considered by its adherents to be the verbatim word of the single incomparable God (Arabic: الله‎, Allāh), and by the Islamic prophet Muhammad's demonstrations and real-life examples (called the Sunnah, collected through narration of his companions in collections of Hadith). The word Islam is a homograph, having multiple meanings, and a triliteral of the word salaam, which directly translates as peace. Other meanings include submission, or the total surrender of oneself to God (see Islam (term)). An adherent of Islam is a Muslim, meaning "one who submits (to God)". The word Muslim is the participle of the same verb of which Islām is the infinitive. Muslims regard their religion as the completed and universal version of a monotheistic faith revealed at many times and places before, including, notably, to the prophets Abraham, Moses and Jesus. Islamic tradition holds that previous messages and revelations have been changed and distorted over time.
Religious practices include the Five Pillars of Islam, which are five duties that unite Muslims into a community. Islamic law (Arabic: شريعة Šarīʿah) touches on virtually every aspect of life and society, encompassing everything from dietary laws and banking to warfare, welfare, and Jihad. The vast majority of Muslims belong to one of two major denominations, the Sunni (87-90%) and Shi'a (10-13%). Islam is the predominant religion in much of Africa, the Middle East and major parts of Asia. Large communities are also found in China, Russia and the Caribbean. About 13% of Muslims live in Indonesia, the largest Muslim country, 31% in the Indian Subcontinent, and 20% in Arab countries. Converts and immigrant communities are found in almost every part of the world. With 1.57 billion Muslims (see Islam by country), Islam is the second-largest religion in the world and arguably the fastest growing religion in the world.
Contents
• 1 Etymology and meaning
• 2 Articles of faith
o 2.1 God
o 2.2 Qur'an
o 2.3 Angels
o 2.4 Muhammad
o 2.5 Resurrection and judgment
o 2.6 Predestination and free will
• 3 Duties and practices
o 3.1 Five Pillars
o 3.2 Law
 3.2.1 Religion and state
o 3.3 Etiquette and diet
o 3.4 Jihad
• 4 History
o 4.1 Rise of the caliphate and Islamic civil war (632–750)
o 4.2 Golden Age (750–1258)
o 4.3 Crusades, Reconquista and Mongol invasion
o 4.4 Turkish, Iranian and Indian empires (1030–1918)
o 4.5 Modern times (1918–present)
• 5 Community
o 5.1 Demographics
o 5.2 Mosques
o 5.3 Family life
o 5.4 Calendar
• 6 Other religions
• 7 Denominations
o 7.1 Sunni
o 7.2 Shi'a
o 7.3 Sufism
o 7.4 Others

Etymology and meaning
The word Islam is a verbal noun originating from the triliteral root s-l-m, and is derived from the Arabic verb Aslama, which means "to accept, surrender or submit." Thus, Islam means acceptance of and submission to God, and believers must demonstrate this by worshipping him, following his commands, and avoiding polytheism. The word is given a number of meanings in the Qur'an. In some verses (ayat), the quality of Islam as an internal conviction is stressed: "Whomsoever God desires to guide, He expands his breast to Islam." Other verses connect islām and dīn (usually translated as "religion"): "Today, I have perfected your religion (dīn) for you; I have completed My blessing upon you; I have approved Islam for your religion." Still others describe Islam as an action of returning to God—more than just a verbal affirmation of faith. Another technical meaning in Islamic thought is as one part of a triad of islam, imān (faith), and ihsān (excellence) where it represents acts of worship (`ibādah) and Islamic law (sharia).
Articles of faith
The Qur'an states that all Muslims must believe in God, his revelations, his angels, his messengers, and in the "Day of Judgment". Also, there are other beliefs that differ between particular sects. The Sunni concept of predestination is called divine decree, while the Shi'a version is called divine justice. Unique to the Shi'a is the doctrine of Imamah, or the political and spiritual leadership of the Imams.
Muslims believe that God revealed his final message to humanity through the Islamic prophet Muhammad via the archangel Gabriel (Jibrīl). For them, Muhammad was God's final prophet and the Qur'an is the holy book of revelations he received over more than two decades. In Islam, prophets are men selected by God to be his messengers. Muslims believe that prophets are human and not divine, though some are able to perform miracles to prove their claim. Islamic prophets are considered to be the closest to perfection of all humans, and are uniquely the recipients of divine revelation—either directly from God or through angels. The Qur'an mentions the names of numerous figures considered prophets in Islam, including Adam, Noah, Abraham, Moses and Jesus, among others. Islamic theology says that all of God's messengers since Adam preached the message of Islam—submission to the will of God. Islam is described in the Qur'an as "the primordial nature upon which God created mankind", and the Qur'an states that the proper name Muslim was given by Abraham.
As a historical phenomenon, Islam originated in Arabia in the early 7th century. Islamic texts depict Judaism and Christianity as prophetic successor traditions to the teachings of Abraham. The Qur'an calls Jews and Christians "People of the Book" (ahl al-kitāb), and distinguishes them from polytheists. Muslims believe that parts of the previously revealed scriptures, the Tawrat (Torah) and the Injil (Gospels), had become distorted—either in interpretation, in text, or both.
God
Islam's fundamental theological concept is tawhīd—the belief that there is only one god. The Arabic term for God is Allāh; most scholars believe it was derived from a contraction of the words al- (the) and ʾilāh (deity, masculine form), meaning "the god" (al-ilāh), but others trace its origin to the Aramaic Alāhā. The first of the Five Pillars of Islam, tawhīd is expressed in the shahadah (testification), which declares that there is no god but God, and that Muhammad is God's messenger. In traditional Islamic theology, God is beyond all comprehension; Muslims are not expected to visualize God but to worship and adore him as a protector. Although Muslims believe that Jesus was a prophet, they reject the Christian doctrine of the Trinity, comparing it to polytheism. In Islamic theology, Jesus was just a man and not the son of God. God is described in a chapter (sura) of the Qur'an as "…God, the One and Only; God, the Eternal, Absolute; He begetteth not, nor is He begotten; And there is none like unto Him."
Qur'an

The first sura in a Qur'anic manuscript by Hattat Aziz Efendi
Muslims consider the Qur'an to be the literal word of God; it is the central religious text of Islam. Muslims believe that the verses of the Qur'an were revealed to Muhammad by God through the angel Gabriel on many occasions between 610 and his death on June 8, 632. The Qur'an was reportedly written down by Muhammad's companions (sahabah) while he was alive, although the prime method of transmission was orally. It was compiled in the time of Abu Bakr, the first caliph, and was standardized under the administration of Uthman, the third caliph. From textual evidence Islamic studies scholars find that the Qur'an of today has not changed significantly over the years.
The Qur'an is divided into 114 suras, or chapters, which combined, contain 6,236 āyāt, or verses. The chronologically earlier suras, revealed at Mecca, are primarily concerned with ethical and spiritual topics. The later Medinan suras mostly discuss social and moral issues relevant to the Muslim community. The Qur'an is more concerned with moral guidance than legal instruction, and is considered the "sourcebook of Islamic principles and values". Muslim jurists consult the hadith, or the written record of Muhammad's life, to both supplement the Qur'an and assist with its interpretation. The science of Qur'anic commentary and exegesis is known as tafsir.[34]
The word Qur'an means "recitation". When Muslims speak in the abstract about "the Qur'an", they usually mean the scripture as recited in Arabic rather than the printed work or any translation of it. To Muslims, the Qur'an is perfect only as revealed in the original Arabic; translations are necessarily deficient because of language differences, the fallibility of translators, and the impossibility of preserving the original's inspired style. Translations are therefore regarded only as commentaries on the Qur'an, or "interpretations of its meaning", not as the Qur'an itself.[35]
Angels
Main article: Angels in Islam
Belief in angels is crucial to the faith of Islam. The Arabic word for angel (malak) means "messenger", like its counterparts in Hebrew (malakh) and Greek (angelos). According to the Qur'an, angels do not possess free will, and worship God in perfect obedience.[36] Angels' duties include communicating revelations from God, glorifying God, recording every person's actions, and taking a person's soul at the time of death. They are also thought to intercede on man's behalf. The Qur'an describes angels as "messengers with wings—two, or three, or four (pairs): He [God] adds to Creation as He pleases…"[37]
Muhammad
Main article: Muhammad
Muhammad (c. 570 – June 8, 632) is the prophet of Islam. He was a religious, political, and military leader who founded the religion of Islam. Muslims view him not as the creator of a new religion, but as the restorer of the original, uncorrupted monotheistic faith of Adam, Abraham, Moses, Jesus and others. In Muslim tradition, Muhammad is viewed as the last and the greatest in a series of prophets—as the man closest to perfection, the possessor of all virtues.[38] For the last 23 years of his life, beginning at age 40, Muhammad reported receiving revelations from God. The content of these revelations, known as the Qur'an, was memorized and recorded by his companions.[39]


The Masjid al-Nabawi ("Mosque of the Prophet") in Madina is the site of Muhammad's tomb.
During this time, Muhammad preached to the people of Mecca, imploring them to abandon polytheism. Although some converted to Islam, Muhammad and his followers were persecuted by the leading Meccan authorities. After 13 years of preaching, Muhammad and the Muslims performed the Hijra ("emigration") to the city of Medina (formerly known as Yathrib) in 622. There, with the Medinan converts (Ansar) and the Meccan migrants (Muhajirun), Muhammad established his political and religious authority. Within years, two battles had been fought against Meccan forces: the Battle of Badr in 624, which was a Muslim victory, and the Battle of Uhud in 625, which ended inconclusively. Conflict with Medinan Jewish clans who opposed the Muslims led to their exile, enslavement or death, and the Jewish enclave of Khaybar was subdued. At the same time, Meccan trade routes were cut off as Muhammad brought surrounding desert tribes under his control.[40] By 629 Muhammad was victorious in the nearly bloodless Conquest of Mecca, and by the time of his death in 632 he ruled over the Arabian peninsula.[41]
In Islam, the "normative" example of Muhammad's life is called the Sunnah (literally "trodden path"). This example is preserved in traditions known as hadith ("reports"), which recount his words, his actions, and his personal characteristics. The classical Muslim jurist ash-Shafi'i (d. 820) emphasized the importance of the Sunnah in Islamic law, and Muslims are encouraged to emulate Muhammad's actions in their daily lives. The Sunnah is seen as crucial to guiding interpretation of the Qur'an.[42]
Resurrection and judgment
Main article: Qiyama
Belief in the "Day of Resurrection", yawm al-Qiyāmah (also known as yawm ad-dīn, "Day of Judgment" and as-sā`a, "the Last Hour") is also crucial for Muslims. They believe that the time of Qiyāmah is preordained by God but unknown to man. The trials and tribulations preceding and during the Qiyāmah are described in the Qur'an and the hadith, and also in the commentaries of Islamic scholars. The Qur'an emphasizes bodily resurrection, a break from the pre-Islamic Arabian understanding of death. It states that resurrection will be followed by the gathering of mankind, culminating in their judgment by God.[43]
The Qur'an lists several sins that can condemn a person to hell, such as disbelief, usury and dishonesty. Muslims view paradise (jannah) as a place of joy and bliss, with Qur'anic references describing its features and the physical pleasures to come. There are also references to a greater joy—acceptance by God (ridwān).[44] Mystical traditions in Islam place these heavenly delights in the context of an ecstatic awareness of God.[45]
Predestination and free will
Main articles: Predestination in Islam and Adalah
In accordance with the Sunni Islamic belief in predestination, or divine preordainment (al-qadā wa'l-qadar), God has full knowledge and control over all that occurs. This is explained in Qur'anic verses such as "Say: 'Nothing will happen to us except what Allah has decreed for us: He is our protector'…"[46] For Muslims, everything in the world that occurs, good or evil, has been preordained and nothing can happen unless permitted by God. According to Muslim theologians, although events are pre-ordained, man possesses free will in that he has the faculty to choose between right and wrong, and is thus responsible for his actions. According to Islamic tradition, all that has been decreed by God is written in al-Lawh al-Mahfūz, the "Preserved Tablet".[47]
The Shi'a understanding of free will is called "divine justice" (Adalah). This doctrine, originally developed by the Mu'tazila, stresses the importance of man's responsibility for his own actions. In contrast, the Sunni deemphasize the role of individual free will in the context of God's creation and foreknowledge of all things.[48]
Duties and practices
Five Pillars
Main article: Five Pillars of Islam


Muslims performing salah (Islamic prayer)


Rituals of the Hajj (pilgrimage) include walking seven times around the Kaaba in Mecca.
The Five Pillars of Islam (Arabic: أركان الإسلام) are five practices essential to Sunni Islam. Shi'a Muslims subscribe to different sets of pillars which substantially overlap with the Five Pillars.[49] They are:
• The shahadah[50], which is the basic creed or tenet of Islam: "'ašhadu 'al-lā ilāha illā-llāhu wa 'ašhadu 'anna muħammadan rasūlu-llāh", or "I testify that there is none worthy of worship except God and I testify that Muhammad is the Messenger of God." This testament is a foundation for all other beliefs and practices in Islam. Muslims must repeat the shahadah in prayer, and non-Muslims wishing to convert to Islam are required to recite the creed.[51]
• Salah, or ritual prayer, which must be performed five times a day. Each salah is done facing towards the Kaaba in Mecca. Salah is intended to focus the mind on God, and is seen as a personal communication with him that expresses gratitude and worship. Salah is compulsory but flexibility in the specifics is allowed depending on circumstances. In many Muslim countries, reminders called Adhan (call to prayer) are broadcast publicly from local mosques at the appropriate times. The prayers are recited in the Arabic language, and consist of verses from the Qur'an.[52]
• Zakat, or alms-giving. This is the practice of giving based on accumulated wealth, and is obligatory for all Muslims who can afford it. A fixed portion is spent to help the poor or needy, and also to assist the spread of Islam. The zakat is considered a religious obligation (as opposed to voluntary charity) that the well-off owe to the needy because their wealth is seen as a "trust from God's bounty". The Qur'an and the hadith also suggest a Muslim give even more as an act of voluntary alms-giving (sadaqah).[53]
• Sawm, or fasting during the month of Ramadan. Muslims must not eat or drink (among other things) from dawn to dusk during this month, and must be mindful of other sins. The fast is to encourage a feeling of nearness to God, and during it Muslims should express their gratitude for and dependence on him, atone for their past sins, and think of the needy. Sawm is not obligatory for several groups for whom it would constitute an undue burden. For others, flexibility is allowed depending on circumstances, but missed fasts usually must be made up quickly. Some Muslim groups do not fast during Ramadan, and instead have fasts different times of the year.[54]
• The Hajj, which is the pilgrimage during the Islamic month of Dhu al-Hijjah in the city of Mecca. Every able-bodied Muslim who can afford it must make the pilgrimage to Mecca at least once in his or her lifetime. When the pilgrim is about ten kilometers from Mecca, he must dress in Ihram clothing, which consists of two white seamless sheets. Rituals of the Hajj include walking seven times around the Kaaba, touching the Black Stone, running seven times between Mount Safa and Mount Marwah, and symbolically stoning the Devil in Mina. The pilgrim, or the hajji, is honored in his or her community, although Islamic teachers say that the Hajj should be an expression of devotion to God instead of a means to gain social standing.[55]
Law
Main articles: Sharia and Fiqh
The Sharia (literally: "the path leading to the watering place") is Islamic law formed by traditional Islamic scholarship, which most Muslim groups adhere to. In Islam, Sharia is the expression of the divine will, and "constitutes a system of duties that are incumbent upon a Muslim by virtue of his religious belief".[56]
Islamic law covers all aspects of life, from matters of state, like governance and foreign relations, to issues of daily living. The Qur'an defines hudud as the punishments for five specific crimes: unlawful intercourse, false accusation of unlawful intercourse, consumption of alcohol, theft, and highway robbery. The Qur'an and Sunnah also contain laws of inheritance, marriage, and restitution for injuries and murder, as well as rules for fasting, charity, and prayer. However, these prescriptions and prohibitions may be broad, so their application in practice varies. Islamic scholars (known as ulema) have elaborated systems of law on the basis of these rules and their interpretations.[57]
Fiqh, or "jurisprudence", is defined as the knowledge of the practical rules of the religion. The method Islamic jurists use to derive rulings is known as usul al-fiqh ("legal theory", or "principles of jurisprudence"). According to Islamic legal theory, law has four fundamental roots, which are given precedence in this order: the Qur'an, the Sunnah (actions and sayings of Muhammad), the consensus of the Muslim jurists (ijma), and analogical reasoning (qiyas). For early Islamic jurists, theory was less important than pragmatic application of the law. In the 9th century, the jurist ash-Shafi'i provided a theoretical basis for Islamic law by codifying the principles of jurisprudence (including the four fundamental roots) in his book ar-Risālah.[58]
Religion and state
Mainstream Islamic law does not distinguish between "matters of church" and "matters of state"; the ulema function as both jurists and theologians. In practice, Islamic rulers frequently bypassed the Sharia courts with a parallel system of so-called "Grievance courts" over which they had sole control. As the Muslim world came into contact with Western secular ideals, Muslim societies responded in different ways. Turkey has been governed as a secular state ever since the reforms of Mustafa Kemal Atatürk. In contrast, the 1979 Iranian Revolution replaced a mostly secular regime with an Islamic republic led by the Ayatollah Khomeini.[59]
Etiquette and diet
Main articles: Adab (behavior) and Islamic dietary laws
Many practices fall in the category of adab, or Islamic etiquette. This includes greeting others with "as-salamu `alaykum" ("peace be unto you"), saying bismillah ("in the name of God") before meals, and using only the right hand for eating and drinking. Islamic hygienic practices mainly fall into the category of personal cleanliness and health, such as the circumcision of male offspring. Islamic burial rituals include saying the Salat al-Janazah ("funeral prayer") over the bathed and enshrouded dead body, and burying it in a grave. Muslims, as with Jews, are restricted in their diet. Prohibited foods include pork products, blood, carrion, and alcohol. All meat must come from a herbivorous animal slaughtered in the name of God by a Muslim, Jew, or Christian, with the exception of game that one has hunted or fished for oneself. Food permissible for Muslims is known as halal food.[60]
Jihad
Main articles: Jihad and Islamic military jurisprudence
Jihad means "to strive or struggle" (in the way of God) and is considered the "Sixth Pillar of Islam" by a minority of Sunni Muslim authorities.[61] Jihad, in its broadest sense, is classically defined as "exerting one's utmost power, efforts, endeavors, or ability in contending with an object of disapprobation." Depending on the object being a visible enemy, the devil, and aspects of one's own self, different categories of Jihad are defined.[62] Jihad, when used without any qualifier, is understood in its military aspect.[63][64] Jihad also refers to one's striving to attain religious and moral perfection.[65] Some Muslim authorities, especially among the Shi'a and Sufis, distinguish between the "greater jihad", which pertains to spiritual self-perfection, and the "lesser jihad", defined as warfare.[66]
Within Islamic jurisprudence, jihad is usually taken to mean military exertion against non-Muslim combatants in the defense or expansion of the Islamic state, the ultimate purpose of which is to universalize Islam. Jihad, the only form of warfare permissible in Islamic law, may be declared against apostates, rebels, highway robbers, violent groups, un-Islamic leaders or states which refuse to submit to the authority of Islam.[67][68] Most Muslims today interpret Jihad as only a defensive form of warfare: the external Jihad includes a struggle to make the Islamic societies conform to the Islamic norms of justice.[69]
Under most circumstances and for most Muslims, jihad is a collective duty (fard kifaya): its performance by some individuals exempts the others. Only for those vested with authority, especially the sovereign (imam), does jihad become an individual duty. For the rest of the populace, this happens only in the case of a general mobilization.[68] For most Shias, offensive jihad can only be declared by a divinely appointed leader of the Muslim community, and as such is suspended since Muhammad al-Mahdi's[70] occultation in 868 AD.[71]
History
Main articles: Muslim history and Spread of Islam
Islam's historical development resulted in major political, economic, and military effects inside and outside the Islamic world. Within a century of Muhammad's first recitations of the Qur'an, an Islamic empire stretched from the Atlantic Ocean in the west to Central Asia in the east. This new polity soon broke into civil war, and successor states fought each other and outside forces. However, Islam continued to spread into regions like Africa, the Indian subcontinent, and Southeast Asia. The Islamic civilization was one of the most advanced in the world during the Middle Ages, but was surpassed by Europe with the economic and military growth of the West. During the 18th and 19th centuries, Islamic dynasties such as the Ottomans and Mughals fell under the sway of European imperial powers. In the 20th century new religious and political movements and newfound wealth in the Islamic world led to both rebirth and conflict.[72]
Rise of the caliphate and Islamic civil war (632–750)
Further information: Succession to Muhammad, Muslim conquests, and Battle of Karbala
Muhammad began preaching Islam at Mecca before migrating to Medina, from where he united the tribes of Arabia into a singular Arab Muslim religious polity. With Muhammad's unexpected death in 632 (from illness)[73], disagreement broke out over who would succeed him as leader of the Muslim community. Umar ibn al-Khattab, a prominent companion of Muhammad, nominated Abu Bakr, who was Muhammad's intimate friend and collaborator. Others added their support and Abu Bakr was made the first caliph. This choice was disputed by some of Muhammad's companions, who held that Ali ibn Abi Talib, his cousin and son-in-law, had been designated his successor. Abu Bakr's immediate task was to avenge a recent defeat by Byzantine (or Eastern Roman Empire) forces, although he first had to put down a rebellion by Arab tribes in an episode known as the Ridda wars, or "Wars of Apostasy".[74]


The territory of the Caliphate in 750
His death in 634 resulted in the succession of Umar as the caliph, followed by Uthman ibn al-Affan and Ali ibn Abi Talib, Muhammah's cousin and son-in-law. These four are known as al-khulafā' ar-rāshidūn ("Rightly Guided Caliphs"). Under them, the territory under Muslim rule expanded deeply into Persian and Byzantine territories.[75]
When Umar was assassinated in 644, the election of Uthman as successor was met with increasing opposition. In 656, Uthman was also killed, and Ali assumed the position of caliph. After fighting off opposition in the first civil war (the "First Fitna"), Ali was assassinated by Kharijites in 661. Following this, Mu'awiyah, who was governor of the Levant, seized power and began the Umayyad dynasty.[76]
Although there was discord, the period immediately following Muhammad's death until the death of his cousin and son-in-law, Ali, in 661 is remembered as a kind of Golden age by some Muslims. It was the Age of the Rashidun or "rightly-guided ones," when Muhammad's close companions led the community of Muslims.[77]
These disputes over religious and political leadership would give rise to schism in the Muslim community. The majority accepted the legitimacy of the three rulers prior to Ali, and became known as Sunnis. A minority disagreed, and believed that Ali was the only rightful successor; they became known as the Shi'a.[78] After Mu'awiyah's death in 680, conflict over succession broke out again in a civil war known as the "Second Fitna". Afterward, the Umayyad dynasty prevailed for seventy years, and was able to conquer the Maghrib and Al-Andalus (the Iberian Peninsula, former Visigothic Hispania) and the Narbonnese Gaul in the west as well as expand Muslim territory into Sindh and the fringes of Central Asia.[79] While the Muslim-Arab elite engaged in conquest, some devout Muslims began to question the piety of indulgence in a worldly life, emphasizing, rather, poverty, humility, and avoidance of sin based on renunciation of bodily desires. Devout Muslim ascetic exemplars such as Hasan al-Basri would inspire a movement that would evolve into Sufism.[80]
For the Umayyad aristocracy, Islam was viewed as a religion for Arabs only;[81] the economy of the Umayyad empire was based on the assumption that a majority of non-Muslims (Dhimmis) would pay taxes to the minority of Muslim Arabs. A non-Arab who wanted to convert to Islam was supposed to first become a client of an Arab tribe. Even after conversion, these new Muslims (mawali) did not achieve social and economic equality with the Arabs. The descendants of Muhammad's uncle Abbas ibn Abd al-Muttalib rallied discontented mawali, poor Arabs, and some Shi'a against the Umayyads and overthrew them with the help of their propagandist and general Abu Muslim, inaugurating the Abbasid dynasty in 750.[82] Under the Abbasids, Islamic civilization flourished in the "Islamic Golden Age", with its capital at the cosmopolitan city of Baghdad.[83]
Golden Age (750–1258)
Main article: Islamic Golden Age
Further information: Muslim Agricultural Revolution
By the late 9th century, the Abbasid caliphate began to fracture as various regions gained increasing levels of autonomy. Across North Africa, Persia, and Central Asia emirates formed as provinces broke away. The monolithic Arab empire gave way to a more religiously homogenized Muslim world where the Shia Fatimids contested even the religious authority of the caliphate. By 1055 the Seljuq Turks had eliminated the Abbasids as a military power, nevertheless they continued to respect the caliph's titular authority.[84] During this time expansion of the Muslim world continued, by both conquest and peaceful proselytism even as both Islam and Muslim trade networks were extending into sub-Saharan West Africa, Central Asia, Volga Bulgaria and the Malay archipelago.[2]
The Golden Age saw new legal, philosophical, and religious developments. The major hadith collections were compiled and the four modern Sunni Madh'habs were established. Islamic law was advanced greatly by the efforts of the early 9th century jurist al-Shafi'i; he codified a method to establish the reliability of hadith, a topic which had been a locus of dispute among Islamic scholars.[85] Philosophers Ibn Sina (Avicenna) and Al-Farabi sought to incorporate Greek principles into Islamic theology, while others like the 11th century theologian Abu Hamid al-Ghazzali argued against them and ultimately prevailed.[86] Finally, Sufism and Shi'ism both underwent major changes in the 9th century. Sufism became a full-fledged movement that had moved towards mysticism and away from its ascetic roots, while Shi'ism split due to disagreements over the succession of Imams.[87]
The spread of the Islamic dominion induced hostility among medieval ecclesiastical Christian authors who saw Islam as an adversary in the light of the large numbers of new Muslim converts. This opposition resulted in polemical treatises which depicted Islam as the religion of the antichrist and of Muslims as libidinous and subhuman.[88] In the medieval period, a few Arab philosophers like the poet Al-Ma'arri adopted a critical approach to Islam, and the Jewish philosopher Maimonides contrasted Islamic views of morality to Jewish views that he himself elaborated.[89]
Crusades, Reconquista and Mongol invasion
Main articles: Crusades and Reconquista
Further information: Mongol invasion of Central Asia and Ilkhanate


Artistic depiction of the Battle of Hattin in 1187, where Jerusalem was recaptured by Saladin's Ayyubid forces
Starting in the 9th century, Muslim conquests in the West began to be reversed. The Reconquista was launched against Muslim principalities in Iberia, and Muslim Italian possessions were lost to the Normans. From the 11th century onwards alliances of European Christian kingdoms mobilized to launch a series of wars known as the Crusades, aimed at reversing Muslim military conquests within the eastern part of the former Roman Empire, especially in the Holy Land. Initially successful in this aim, and establishing the Crusader states, these gains were later reversed by subsequent Muslim generals such as Saladin, who recaptured Jerusalem in 1187.[90] In the east the Mongol Empire put an end to the Abbassid dynasty at the Battle of Baghdad in 1258, as they overran the Muslim lands in a series of invasions. Meanwhile in Egypt, the slave-soldier Mamluks took control in an uprising in 1250[91] and in alliance with the Golden Horde halted the Mongol armies at the Battle of Ain Jalut. But Mongol rule extended across the breadth of almost all Muslim lands in Asia and Islam was temporarily replaced by Buddhism as the official religion of the land. Over the next century the Mongol Khanates converted to Islam and this religious and cultural absorption ushered in a new age of Mongol-Islamic synthesis that shaped the further spread of Islam in central Asia, eastern Europe and the Indian subcontinent. The Crimean Khanate was one of the strongest powers in Eastern Europe until the end of the 17th century.[92]
The Black Death ravaged much of the Islamic world in the mid-14th century.[93] It is probable that the Mongols and merchant caravans making use of the opportunities of free passage offered by the Pax Mongolica inadvertently brought the plague from Central Asia to the Middle East and Europe.[94] Plague epidemics kept returning to the Islamic world up to the 19th century.[95]
Turkish, Iranian and Indian empires (1030–1918)
The Seljuk Turks conquered Abbassid lands and adopted Islam and become the de facto rulers of the caliphate. They captured Anatolia by defeating the Byzantines at the Battle of Manzikert, thereby precipitating the call for Crusades. They however fell apart rapidly in the second half of the 12th century giving rise to various semi-autonomous Turkic dynasties. In the 13th and 14th centuries the Ottoman empire (named after Osman I) emerged from among these "Ghazi emirates" and established itself after a string of conquests that included the Balkans, parts of Greece, and western Anatolia. In 1453 under Mehmed II the Ottomans laid siege to Constantinople, the capital of Byzantium, which succumbed shortly thereafter, having been overwhelmed by a far greater number of Ottoman troops and to a lesser extent, cannonry.[96]
Beginning in the 13th century, Sufism underwent a transformation, largely as a result of the efforts of al-Ghazzali to legitimize and reorganize the movement. He developed the model of the Sufi order—a community of spiritual teachers and students.[97] Also of importance to Sufism was the creation of the Masnavi, a collection of mystical poetry by the 13th century Persian poet Rumi. The Masnavi had a profound influence on the development of Sufi religious thought; to many Sufis it is second in importance only to the Qur'an.[98]


The Taj Mahal is a mausoleum located in Agra, India, that was built under Mughal rule[99]
In the early 16th century, the Shi'i Safavid dynasty assumed control in Persia and established Shi'a Islam as an official religion there, and despite periodic setbacks, the Safavids remained powerful for two centuries. Meanwhile, Mamluk Egypt fell to the Ottomans in 1517, who then launched a European campaign which reached as far as the gates of Vienna in 1529.[100] After the invasion of Persia, and sack of Baghdad by the Mongols in 1258, Delhi became the most important cultural centre of the Muslim east.[101] Many Islamic dynasties ruled parts of the Indian subcontinent starting from the 12th century. The prominent ones include the Delhi Sultanate (1206–1526) and the Mughal empire (1526–1857). These empires helped in the spread of Islam in South Asia, but by the early-18th century the Maratha empire became the pre-eminent power in the north of India. By the mid-18th century the British empire had formally ended the Mughal dynasty,[102], and at the end of the 18th century overthrew the Muslim-ruled Kingdom of Mysore. In the 18th century the Wahhabi movement took hold in Saudi Arabia. Founded by the preacher Ibn Abd al-Wahhab, Wahhabism is a fundamentalist ideology that condemns practices like Sufism and the veneration of saints as un-Islamic.[103]
By the 17th and 18th centuries, despite attempts at modernization, the Ottoman empire had begun to feel threatened by European economic and military advantages. In the 19th century, the rise of nationalism resulted in Greece declaring and winning independence in 1829, with several Balkan states following suit after the Ottomans suffered defeat in the Russo-Turkish War of 1877–1878. The Ottoman era came to a close at the end of World War I and the Caliphate was abolished in 1924.[104][105]
In the 19th century, the Salafi, Deobandi and Barelwi movements were initiated.
Modern times (1918–present)
Further information: Fall of the Ottoman Empire, Arab Revolt, Arab–Israeli conflict, and Iranian revolution
By the early years of the 20th century, most of the Muslim world outside the Ottoman empire had been absorbed into the empires of non-Islamic European powers. After World War I losses, nearly all of the Ottoman empire was also parceled out as European protectorates or spheres of influence. In the course of the 20th century, most of these European-ruled territories became independent, and new issues such as oil wealth and relations with the State of Israel have assumed prominence.[106] During this time, many Muslims migrated, as indentured servants, from mostly India and Indonesia to the Caribbean, forming the largest Muslim populations by percentage in the Americas.[107] Additionally, the resulting urbanization and increase in trade in Africa brought Muslims to settle in new areas and spread their faith. As a result, Islam in sub-Saharan Africa likely doubled between 1869 and 1914.[108] The Organization of the Islamic Conference (OIC), consisting of Muslim countries, was formally established in September 1969 after the burning of the Al-Aqsa Mosque in Jerusalem.[109]


Muslim boys reflect, following a morning of worship. Jama Masjid, Delhi, India.
The 20th century saw the creation of many new Islamic "revivalist" movements. Groups such as the Muslim Brotherhood in Egypt and Jamaat-e-Islami in Pakistan advocate a totalistic and theocratic alternative to secular political ideologies. Sometimes called Islamist, they see Western cultural values as a threat, and promote Islam as a comprehensive solution to every public and private question of importance. In countries like Iran and Afghanistan (under the Taliban), revolutionary movements replaced secular regimes with Islamist states, while transnational groups like Osama bin Laden's al-Qaeda engage in terrorism to further their goals. In contrast, Liberal Islam is a movement that attempts to reconcile religious tradition with modern norms of secular governance and human rights. Its supporters say that there are multiple ways to read Islam's sacred texts, and stress the need to leave room for "independent thought on religious matters".[110]
Modern critique of Islam includes accusations that Islam is intolerant of criticism and that Islamic law is too hard on apostates. Critics like Ibn Warraq question the morality of the Qu'ran, saying that its contents justify the mistreatment of women and encourage antisemitic remarks by Muslim theologians.[111] Such claims are disputed by Muslim writers like Fazlur Rahman Malik,[112] Syed Ameer Ali,[113] Ahmed Deedat,[114] and Yusuf Estes.[115] Others like Daniel Pipes and Martin Kramer focus more on criticizing the spread of Islamic fundamentalism, a danger they feel has been ignored.[116] Montgomery Watt and Norman Daniel dismiss many of the criticisms as the product of old myths and polemics.[117] The rise of Islamophobia, according to Carl Ernst, had contributed to the negative views about Islam and Muslims in the West.[118]
Pascal Bruckner and Paul Berman on the other hand have entered the "Islam in Europe" debate. Berman identifies a "reactionary turn in the intellectual world" represented by Western scholars who idealize Islam.[119]
Community
Main article: Muslim world
Demographics
See also: List of countries by Muslim population


World Muslim Population Percentage
A comprehensive 2009 demographic study of 232 countries and territories reported that 23% of the global population or 1.57 billion people are Muslims.[120] Of those, 87-90% are Sunni and 10-13% are Shi'a,[121] with a small minority belonging to other sects. Approximately 50 countries are Muslim-majority,[122] and Arabs account for around 20% of all Muslims worldwide. Approximately 62% of the world's Muslims live in Asia, with over 683 million adherents in Bangladesh, India, Indonesia, and Pakistan.[123] According to U.S. government figures, in 2006 there were 20 million Muslims in China.[124] In the Middle East, the non-Arab countries of Turkey and Iran are the largest Muslim-majority countries; in Africa, Egypt and Nigeria have the most populous Muslim communities.[125] Islam is the second largest religion after Christianity in many European countries.[126]
Mosques
Main article: Mosque


The Sultan Ahmed Mosque in Istanbul, Turkey.
A mosque is a place of worship for Muslims, who often refer to it by its Arabic name, masjid. The word mosque in English refers to all types of buildings dedicated to Islamic worship, although there is a distinction in Arabic between the smaller, privately owned mosque and the larger, "collective" mosque (masjid jāmi`). Although the primary purpose of the mosque is to serve as a place of prayer, it is also important to the Muslim community as a place to meet and study. Modern mosques have evolved greatly from the early designs of the 7th century, and contain a variety of architectural elements such as minarets.[127]
Family life
See also: Women and Islam
The basic unit of Islamic society is the family, and Islam defines the obligations and legal rights of family members. The father is seen as financially responsible for his family, and is obliged to cater for their well-being. The division of inheritance is specified in the Qur'an, which states that most of it is to pass to the immediate family, while a portion is set aside for the payment of debts and the making of bequests. The woman's share of inheritance is generally half of that of a man with the same rights of succession.[128] Marriage in Islam is a civil contract which consists of an offer and acceptance between two qualified parties in the presence of two witnesses. The groom is required to pay a bridal gift (mahr) to the bride, as stipulated in the contract.[129]


Canterbury Mosque in Christchurch, New Zealand was built during 1984–1985.[130]
A man may have up to four wives if he believes he can treat them equally, while a woman may have only one husband. In most Muslim countries, the process of divorce in Islam is known as talaq, which the husband initiates by pronouncing the word "divorce".[131] Scholars disagree whether Islamic holy texts justify traditional Islamic practices such as veiling and seclusion (purdah). Starting in the 20th century, Muslim social reformers argued against these and other practices such as polygamy, with varying success. At the same time, many Muslim women have attempted to reconcile tradition with modernity by combining an active life with outward modesty. Certain Islamist groups like the Taliban have sought to continue traditional law as applied to women.[132]
Calendar
Main article: Islamic calendar


The Islamic calendar is based on the lunar cycle.
The formal beginning of the Muslim era was chosen to be the Hijra in 622 CE, which was an important turning point in Muhammad's fortunes. The assignment of this year as the year 1 AH (Anno Hegirae) in the Islamic calendar was reportedly made by Caliph Umar. It is a lunar calendar, with nineteen ordinary years of 354 days and eleven leap years of 355 days in a thirty-year cycle. Islamic dates cannot be converted to CE/AD dates simply by adding 622 years: allowance must also be made for the fact that each Hijri century corresponds to only 97 years in the Christian calendar.[133]
The year 1428 AH coincides almost completely with 2007 CE.
Islamic holy days fall on fixed dates of the lunar calendar, which means that they occur in different seasons in different years in the Gregorian calendar. The most important Islamic festivals are Eid al-Fitr (Arabic: عيد الفطر) on the 1st of Shawwal, marking the end of the fasting month Ramadan, and Eid al-Adha (Arabic: عيد الأضحى) on the 10th of Dhu al-Hijjah, coinciding with the pilgrimage to Mecca.[134] Similar to the Jewish calendar, days in the Islamic calendar last from sunset to sunset.[135]
Other religions
Main articles: Islam and other religions and Criticism of Islam


A view of the Dome of the Rock on the Temple Mount in Jerusalem, a holy site in both Islam and Judaism that has been a source of controversy


The Al-Aqsa Mosque congregation building. Muslims believe that Muhammad ascended to heaven near this site.
According to Islamic doctrine, Islam was the primordial religion of mankind, professed by Adam.[136] At some point, a religious split occurred, and God began sending prophets to bring his revelations to the people.[137] In this view, Abraham, Moses, Hebrew prophets, and Jesus were all Prophets in Islam, but their message and the texts of the Torah and the Gospels were corrupted by Jews and Christians. Similarly, children of non-Muslim families are born Muslims, but are converted to another faith by their parents.[138]
Islamic law divides non-Muslims into several categories, depending on their relation with the Islamic state. Christians and Jews who live under Islamic rule are known as dhimmis ("protected peoples"). According to this regulation, the personal safety and security of property of the dhimmis were guaranteed in return for paying tribute (jizya) to the Islamic state. The status was extended to other groups like Zoroastrians and Hindus[139], but not to atheists or agnostics.[140] Those who live in non-Muslim lands (dar al-harb) are known as harbis, and upon entering into an alliance with the Muslim state become known as ahl al-ahd. Those who receive a guarantee of safety while residing temporarily in Muslim lands are known as ahl al-amān. Their legal position is similar to that of the dhimmi except that they are not required to pay the jizya. The people of armistice (ahl al-hudna) are those who live outside of Muslim territory and agree to refrain from attacking the Muslims.[141][142] Apostasy is prohibited, and is punishable by death.[143][144]
The Alevi, Yazidi, Druze, Ahmadiyya, Bábí, Bahá'í, Berghouata and Ha-Mim movements either emerged out of Islam or came to share certain beliefs with Islam. Some consider themselves separate while others still sects of Islam though controversial in certain beliefs with mainstream Muslims. Sikhism, founded by Guru Nanak in late 15th century Punjab, incorporates aspects of both Islam and Hinduism.[145]
Denominations
Main article: Islamic schools and branches
Islam consists of a number of religious denominations that are essentially similar in belief but which have significant theological and legal differences. The primary division is between the Sunni and the Shi'a, with Sufism generally considered to be a mystical inflection of Islam rather than a distinct school. According to most sources, approximately 85% of the world's Muslims are Sunni, 14% are Shi'a with the 1% beiing other various small minorities and Islamic sects.[146]
Sunni
Main article: Sunni Islam
Sunni Muslims are the largest group in Islam hence the title 'Ahl as-Sunnah wa’l-Jamā‘ah' (people of the principle and majority). In Arabic, as-Sunnah literally means "principle" or "path". The Sunnah (the example of Muhammad's life) as recorded in the Qur'an and the hadith is the main pillar of Sunni doctrine. Sunnis believe that the first four caliphs were the rightful successors to Muhammad; since God did not specify any particular leaders to succeed him, those leaders had to be elected. Sunnis recognize four major madh'habs (schools of thought): Hanafi, Maliki, Shafi'i, and Hanbali. All four accept the validity of the others and a Muslim may choose any one that he or she finds agreeable.
There are other Islamic sects that may be considered as being Sunni yet are believed to have departed from the majority by introducing bidah (innovations) and extreme political views which are divorced from Islam. There are also several orthodox theological or philosophical traditions within Sunnism such as the recent Salafi movement, which sees itself as restorationist and claims to derive its teachings from the original sources of Islam by refuting the established schools of thought.[147]
Shi'a
Main article: Shia Islam
See also: Succession to Muhammad
The Shi'a, who constitute the second-largest branch of Islam, believe in the political and religious leadership of Imams from the progeny of Ali ibn Abi Talib, who according to most Shi'a are in a state of ismah, meaning infallibility. They believe that Ali ibn Abi Talib, as the cousin and son-in-law of Muhammad, was his rightful successor, and they call him the first Imam (leader), rejecting the legitimacy of the previous Muslim caliphs. To most Shi'a, an Imam rules by right of divine appointment and holds "absolute spiritual authority" among Muslims, having final say in matters of doctrine and revelation.[148][149] Shi'a Islam has several branches, the largest of which is the Twelvers (iṯnāʿašariyya) which the label Shi'a generally refers to. Although the Twelver Shi'a share many core practices with the Sunni, the two branches disagree over the proper importance and validity of specific collections of hadith. The Twelver Shi'a follow a legal tradition called Ja'fari jurisprudence.[150] Other smaller groups include the Ismaili and Zaidi, who differ from Twelvers in both their line of successors and theological beliefs.[151]
Sufism


Sufi whirling dervishes in Turkey
Main article: Sufism
Not strictly a denomination, Sufism is a mystical-ascetic form of Islam. By focusing on the more spiritual aspects of religion, Sufis strive to obtain direct experience of God by making use of "intuitive and emotional faculties" that one must be trained to use.[152] Sufism and Islamic law are usually considered to be complementary, although Sufism has been criticized by some Muslims for being an unjustified religious innovation. Most Sufi orders, or tariqas, can be classified as either Sunni or Shi'a.[153]
Others
The Kharijites are a sect that dates back to the early days of Islam. The only surviving branch of the Kharijites is Ibadism. Unlike most Kharijite groups, Ibadism does not regard sinful Muslims as unbelievers. The Imamate is an important topic in Ibadi legal literature, which stipulates that the leader should be chosen solely on the basis of his knowledge and piety, and is to be deposed if he acts unjustly. Most Ibadi Muslims live in Oman.[154]
There are communities of Ibadis that took refuge in the Mzab oases in southern Algeria, the Nafusa Mountains in western Libya, and in Djerba Island (Tunisia), in order to avoid persecution in certain periods of history.[155] Another large group includes the Ahmadiyya.

Internet

Internet

Visualization of the various routes through a portion of the Internet
The Internet is a global system of interconnected computer networks that use the standardized Internet Protocol Suite (TCP/IP) to serve billions of users worldwide. It is a network of networks that consists of millions of private and public, academic, business, and government networks of local to global scope that are linked by copper wires, fiber-optic cables, wireless connections, and other technologies. The Internet carries a vast array of information resources and services, most notably the inter-linked hypertext documents of the World Wide Web (WWW) and the infrastructure to support electronic mail. In addition it supports popular services such as online chat, file transfer and file sharing, gaming, commerce, social networking, publishing, video on demand, and teleconferencing and telecommunications. Voice over Internet Protocol (VoIP) applications allow person-to-person communication via voice and video.
The origins of the Internet reach back to the 1960s when the United States funded research projects of its military agencies to build robust, fault-tolerant and distributed computer networks. This research and a period of civilian funding of a new U.S. backbone by the National Science Foundation spawned worldwide participation in the development of new networking technologies and led to the commercialization of an international network in the mid 1990s, and resulted in the following popularization of countless applications in virtually every aspect of modern human life. As of 2009, an estimated quarter of Earth's population uses the services of the Internet.
Contents
• 1 Terminology
• 2 History
• 3 Technology
o 3.1 Protocols
o 3.2 Structure
• 4 Governance
• 5 Modern uses
• 6 Services
o 6.1 Information
o 6.2 Communication
o 6.3 Data transfer
• 7 Accessibility
• 8 Social impact

Terminology
The terms Internet and World Wide Web are often used in everyday speech without much distinction. However, the Internet and the World Wide Web are not one and the same. The Internet is a global data communications system. It is a hardware and software infrastructure that provides connectivity between computers. In contrast, the Web is one of the services communicated via the Internet. It is a collection of interconnected documents and other resources, linked by hyperlinks and URLs. The term the Internet, when referring to the Internet, has traditionally been treated as a proper noun and written with an initial capital letter. There is a trend to regard it as a generic term or common noun and thus write it as "the internet", without the capital.
History
The USSR's launch of Sputnik spurred the United States to create the Advanced Research Projects Agency, known as ARPA, in February 1958 to regain a technological lead. ARPA created the Information Processing Technology Office (IPTO) to further the research of the Semi Automatic Ground Environment (SAGE) program, which had networked country-wide radar systems together for the first time. J. C. R. Licklider was selected to head the IPTO. Licklider moved from the Psycho-Acoustic Laboratory at Harvard University to MIT in 1950, after becoming interested in information technology. At MIT, he served on a committee that established Lincoln Laboratory and worked on the SAGE project. In 1957 he became a Vice President at BBN, where he bought the first production PDP-1 computer and conducted the first public demonstration of time-sharing.

Professor Leonard Kleinrock with one of the first ARPANET Interface Message Processors at UCLA
At the IPTO, Licklider got Lawrence Roberts to start a project to make a network, and Roberts based the technology on the work of Paul Baran, who had written an exhaustive study for the United States Air Force that recommended packet switching (opposed to circuit switching) to achieve better network robustness and disaster survivability. UCLA professor Leonard Kleinrock had provided the theoretical foundations for packet networks in 1962, and later, in the 1970s, for hierarchical routing, concepts which have been the underpinning of the development towards today's Internet.
After much work, the first two nodes of what would become the ARPANET were interconnected between UCLA's School of Engineering and Applied Science and SRI International (SRI) in Menlo Park, California, on October 29, 1969. The ARPANET was one of the "eve" networks of today's Internet. Following on from the demonstration that packet switching worked on the ARPANET, the British Post Office, Telenet, DATAPAC and TRANSPAC collaborated to create the first international packet-switched network service. In the UK, this was referred to as the International Packet Switched Service (IPSS), in 1978. The collection of X.25-based networks grew from Europe and the US to cover Canada, Hong Kong and Australia by 1981. The X.25 packet switching standard was developed in the CCITT (now called ITU-T) around 1976.

A plaque commemorating the birth of the Internet at Stanford University
X.25 was independent of the TCP/IP protocols that arose from the experimental work of DARPA on the ARPANET, Packet Radio Net and Packet Satellite Net during the same time period. Vinton Cerf and Robert Kahn developed the first description of the TCP protocols during 1973 and published a paper on the subject in May 1974. Use of the term "Internet" to describe a single global TCP/IP network originated in December 1974 with the publication of RFC 675, the first full specification of TCP that was written by Vinton Cerf, Yogen Dalal and Carl Sunshine, then at Stanford University. During the next nine years, work proceeded to refine the protocols and to implement them on a wide range of operating systems. The first TCP/IP-based wide-area network was operational by January 1, 1983 when all hosts on the ARPANET were switched over from the older NCP protocols. In 1985, the United States' National Science Foundation (NSF) commissioned the construction of the NSFNET, a university 56 kilobit/second network backbone using computers called "fuzzballs" by their inventor, David L. Mills. The following year, NSF sponsored the conversion to a higher-speed 1.5 megabit/second network. A key decision to use the DARPA TCP/IP protocols was made by Dennis Jennings, then in charge of the Supercomputer program at NSF.
The opening of the network to commercial interests began in 1988. The US Federal Networking Council approved the interconnection of the NSFNET to the commercial MCI Mail system in that year and the link was made in the summer of 1989. Other commercial electronic e-mail services were soon connected, including OnTyme, Telemail and Compuserve. In that same year, three commercial Internet service providers (ISPs) were created: UUNET, PSINet and CERFNET. Important, separate networks that offered gateways into, then later merged with, the Internet include Usenet and BITNET. Various other commercial and educational networks, such as Telenet, Tymnet, Compuserve and JANET were interconnected with the growing Internet. Telenet (later called Sprintnet) was a large privately funded national computer network with free dial-up access in cities throughout the U.S. that had been in operation since the 1970s. This network was eventually interconnected with the others in the 1980s as the TCP/IP protocol became increasingly popular. The ability of TCP/IP to work over virtually any pre-existing communication networks allowed for a great ease of growth, although the rapid growth of the Internet was due primarily to the availability of an array of standardized commercial routers from many companies, the availability of commercial Ethernet equipment for local-area networking, and the widespread implementation and rigorous standardization of TCP/IP on UNIX and virtually every other common operating system.

This NeXT Computer was used by Berners-Lee at CERN and became the world's first Web server.
Although the basic applications and guidelines that make the Internet possible had existed for almost two decades, the network did not gain a public face until the 1990s. On 6 August 1991, CERN, a pan European organisation for particle research, publicized the new World Wide Web project. The Web was invented by English scientist Tim Berners-Lee in 1989. An early popular web browser was ViolaWWW, patterned after HyperCard and built using the X Window System. It was eventually replaced in popularity by the Mosaic web browser. In 1993, the National Center for Supercomputing Applications at the University of Illinois released version 1.0 of Mosaic, and by late 1994 there was growing public interest in the previously academic, technical Internet. By 1996 usage of the word Internet had become commonplace, and consequently, so had its use as a synecdoche in reference to the World Wide Web.
Meanwhile, over the course of the decade, the Internet successfully accommodated the majority of previously existing public computer networks (although some networks, such as FidoNet, have remained separate). During the 1990s, it was estimated that the Internet grew by 100 percent per year, with a brief period of explosive growth in 1996 and 1997. This growth is often attributed to the lack of central administration, which allows organic growth of the network, as well as the non-proprietary open nature of the Internet protocols, which encourages vendor interoperability and prevents any one company from exerting too much control over the network. Using various statistics, Advanced Micro Devices estimated the population of Internet users to be 1.5 billion as of January 2009.[7]
Technology
Protocols
The complex communications infrastructure of the Internet consists of its hardware components and a system of software layers that control various aspects of the architecture. While the hardware can often be used to support other software systems, it is the design and the rigorous standardization process of the software architecture that characterizes the Internet and provides the foundation for its scalability and success. The responsibility for the architectural design of the Internet software systems has been delegated to the Internet Engineering Task Force (IETF). The IETF conducts standard-setting work groups, open to any individual, about the various aspects of Internet architecture. Resulting discussions and final standards are published in a series of publications, called Request for Comments (RFCs), freely available on the IETF web site. The principal methods of networking that enable the Internet are contained in specially designated RFCs that constitute the Internet Standards.
These standards describe a framework known as the Internet Protocol Suite. This is a model architecture that divides methods into a layered system of protocols (RFC 1122, RFC 1123). The layers correspond to the environment or scope in which their services operate. At the top is the Application Layer, the space for the application-specific networking methods used in software applications, e.g., a web browser program. Below this top layer, the Transport Layer connects applications on different hosts via the network (e.g., client-server model) with appropriate data exchange methods. Underlying these layers are the core networking technologies, consisting of two layers. The Internet Layer enables computers to identify and locate each other via Internet Protocol (IP) addresses, and allows them to connect to one-another via intermediate (transit) networks. Lastly, at the bottom of the architecture, is a software layer, the Link Layer, that provides connectivity between hosts on the same local network link, such as a local area network (LAN) or a dial-up connection. The model, also known as TCP/IP, is designed to be independent of the underlying hardware which the model therefore does not concern itself with in any detail. Other models have been developed, such as the Open Systems Interconnection (OSI) model, but they are not compatible in the details of description, nor implementation, but many similarities exist and the TCP/IP protocols are usually included in the discussion of OSI networking.
The most prominent component of the Internet model is the Internet Protocol (IP) which provides addressing systems (IP addresses) for computers on the Internet. IP enables internetworking and essentially establishes the Internet itself. IP Version 4 (IPv4) is the initial version used on the first generation of the today's Internet and is still in dominant use. It was designed to address up to ~4.3 billion (109) Internet hosts. However, the explosive growth of the Internet has led to IPv4 address exhaustion which is estimated to enter its final stage in approximately 2011. A new protocol version, IPv6, was developed in the mid 1990s which provides vastly larger addressing capabilities and more efficient routing of Internet traffic. IPv6 is currently in commercial deployment phase around the world and Internet address registries (RIRs) have begun to urge all resource managers to plan rapid adoption and conversion.
IPv6 is not interoperable with IPv4. It essentially establishes a "parallel" version of the Internet not directly accessible with IPv4 software. This means software upgrades or translator facilities are necessary for every networking device that needs to communicate on the IPv6 Internet. Most modern computer operating systems are already converted to operate with both versions of the Internet Protocol. Network infrastructures, however, are still lagging in this development. Aside from the complex physical connections that make up its infrastructure, the Internet is facilitated by bi- or multi-lateral commercial contracts (e.g., peering agreements), and by technical specifications or protocols that describe how to exchange data over the network. Indeed, the Internet is defined by its interconnections and routing policies.
Structure
The Internet structure and its usage characteristics have been studied extensively. It has been determined that both the Internet IP routing structure and hypertext links of the World Wide Web are examples of scale-free networks. Similar to the way the commercial Internet providers connect via Internet exchange points, research networks tend to interconnect into large subnetworks such as GEANT, GLORIAD, Internet2 (successor of the Abilene Network), and the UK's national research and education network JANET. These in turn are built around smaller networks (see also the list of academic computer network organizations).
Many computer scientists describe the Internet as a "prime example of a large-scale, highly engineered, yet highly complex system". The Internet is extremely heterogeneous; for instance, data transfer rates and physical characteristics of connections vary widely. The Internet exhibits "emergent phenomena" that depend on its large-scale organization. For example, data transfer rates exhibit temporal self-similarity. The principles of the routing and addressing methods for traffic in the Internet reach back to their origins the 1960s when the eventual scale and popularity of the network could not be anticipated. Thus, the possibility of developing alternative structures is investigated.
Governance

ICANN headquarters in Marina Del Rey, California, United States
The Internet is a globally distributed network comprising many voluntarily interconnected autonomous networks. It operates without a central governing body. However, to maintain interoperability, all technical and policy aspects of the underlying core infrastructure and the principal name spaces are administered by the Internet Corporation for Assigned Names and Numbers (ICANN), headquartered in Marina del Rey, California. ICANN is the authority that coordinates the assignment of unique identifiers for use on the Internet, including domain names, Internet Protocol (IP) addresses, application port numbers in the transport protocols, and many other parameters. Globally unified name spaces, in which names and numbers are uniquely assigned, are essential for the global reach of the Internet. ICANN is governed by an international board of directors drawn from across the Internet technical, business, academic, and other non-commercial communities. The US government continues to have the primary role in approving changes to the DNS root zone that lies at the heart of the domain name system. ICANN's role in coordinating the assignment of unique identifiers distinguishes it as perhaps the only central coordinating body on the global Internet. On November 16, 2005, the World Summit on the Information Society, held in Tunis, established the Internet Governance Forum (IGF) to discuss Internet-related issues.
Modern uses
The Internet is allowing greater flexibility in working hours and location, especially with the spread of unmetered high-speed connections and web applications.
The Internet can now be accessed almost anywhere by numerous means, especially through mobile Internet devices. Mobile phones, datacards, handheld game consoles and cellular routers allow users to connect to the Internet from anywhere there is a wireless network supporting that device's technology. Within the limitations imposed by small screens and other limited facilities of such pocket-sized devices, services of the Internet, including email and the web, may be available. Service providers may restrict the services offered and wireless data transmission charges may be significantly higher than other access methods.
The Internet has also become a large market for companies; some of the biggest companies today have grown by taking advantage of the efficient nature of low-cost advertising and commerce through the Internet, also known as e-commerce. It is the fastest way to spread information to a vast number of people simultaneously. The Internet has also subsequently revolutionized shopping—for example; a person can order a CD online and receive it in the mail within a couple of days, or download it directly in some cases. The Internet has also greatly facilitated personalized marketing which allows a company to market a product to a specific person or a specific group of people more so than any other advertising medium. Examples of personalized marketing include online communities such as MySpace, Friendster, Orkut, Facebook and others which thousands of Internet users join to advertise themselves and make friends online. Many of these users are young teens and adolescents ranging from 13 to 25 years old. In turn, when they advertise themselves they advertise interests and hobbies, which online marketing companies can use as information as to what those users will purchase online, and advertise their own companies' products to those users.
The low cost and nearly instantaneous sharing of ideas, knowledge, and skills has made collaborative work dramatically easier, with the help of collaborative software. Not only can a group cheaply communicate and share ideas, but the wide reach of the Internet allows such groups to easily form in the first place. An example of this is the free software movement, which has produced, among other programs, Linux, Mozilla Firefox, and OpenOffice.org. Internet "chat", whether in the form of IRC chat rooms or channels, or via instant messaging systems, allow colleagues to stay in touch in a very convenient way when working at their computers during the day. Messages can be exchanged even more quickly and conveniently than via e-mail. Extensions to these systems may allow files to be exchanged, "whiteboard" drawings to be shared or voice and video contact between team members.
Version control systems allow collaborating teams to work on shared sets of documents without either accidentally overwriting each other's work or having members wait until they get "sent" documents to be able to make their contributions. Business and project teams can share calendars as well as documents and other information. Such collaboration occurs in a wide variety of areas including scientific research, software development, conference planning, political activism and creative writing. Social and political collaboration is also becoming more widespread as both Internet access and computer literacy grow. From the flash mob 'events' of the early 2000s to the use of social networking in the 2009 Iranian election protests, the Internet allows people to work together more effectively and in many more ways than was possible without it.
The Internet allows computer users to remotely access other computers and information stores easily, wherever they may be across the world. They may do this with or without the use of security, authentication and encryption technologies, depending on the requirements. This is encouraging new ways of working from home, collaboration and information sharing in many industries. An accountant sitting at home can audit the books of a company based in another country, on a server situated in a third country that is remotely maintained by IT specialists in a fourth. These accounts could have been created by home-working bookkeepers, in other remote locations, based on information e-mailed to them from offices all over the world. Some of these things were possible before the widespread use of the Internet, but the cost of private leased lines would have made many of them infeasible in practice. An office worker away from their desk, perhaps on the other side of the world on a business trip or a holiday, can open a remote desktop session into his normal office PC using a secure Virtual Private Network (VPN) connection via the Internet. This gives the worker complete access to all of his or her normal files and data, including e-mail and other applications, while away from the office. This concept is also referred to by some network security people as the Virtual Private Nightmare, because it extends the secure perimeter of a corporate network into its employees' homes.
Services
Information
Many people use the terms Internet and World Wide Web (or just the Web) interchangeably, but, as discussed earlier, the two terms are not synonymous. The World Wide Web is a global set of documents, images and other resources, referenced and interconnected by Uniform Resource Locators (URLs) and hyperlinks. These URLs allow users to address the web servers and other devices that store these resources and access them as required using the Hypertext Transfer Protocol (HTTP). HTTP is only one of the communication protocols used on the Internet. Web services may also use HTTP to allow software systems to communicate in order to share and exchange business logic and data.
Software products that can access the resources of the Web are often called user agents. In normal use, web browsers, such as Internet Explorer, Firefox, Opera, Apple Safari, and Google Chrome, let users navigate from one web page to another via hyperlinks. Documents on the web may contain any combination of computer data, including graphics, sounds, text, video, multimedia and interactive content including games, office applications and scientific demonstrations. Through keyword-driven Internet research using search engines like Yahoo! and Google, users worldwide have easy, instant access to a vast and diverse amount of online information. Compared to printed encyclopedias and traditional libraries, the World Wide Web has enabled a sudden and extreme decentralization of information and data.
Using the Web, it is also easier than ever before for individuals and organizations to publish ideas and information to a potentially large audience. Publishing a web page, a blog, or building a website involves little initial cost and many cost-free services are available. Publishing and maintaining large, professional web sites with attractive, diverse and up-to-date information is still a difficult and expensive proposition, however. Many individuals and some companies and groups use web logs or blogs, which are largely used as easily updatable online diaries. Some commercial organizations encourage staff to communicate advice in their areas of specialization in the hope that visitors will be impressed by the expert knowledge and free information, and be attracted to the corporation as a result. One example of this practice is Microsoft, whose product developers publish their personal blogs in order to pique the public's interest in their work. Collections of personal web pages published by large service providers remain popular, and have become increasingly sophisticated. Whereas operations such as Angelfire and GeoCities have existed since the early days of the Web, newer offerings from, for example, Facebook and MySpace currently have large followings. These operations often brand themselves as social network services rather than simply as web page hosts.
Advertising on popular web pages can be lucrative, and e-commerce or the sale of products and services directly via the Web continues to grow. In the early days, web pages were usually created as sets of complete and isolated HTML text files stored on a web server. More recently, websites are more often created using content management or wiki software with, initially, very little content. Contributors to these systems, who may be paid staff, members of a club or other organization or members of the public, fill underlying databases with content using editing pages designed for that purpose, while casual visitors view and read this content in its final HTML form. There may or may not be editorial, approval and security systems built into the process of taking newly entered content and making it available to the target visitors.
Communication
E-mail is an important communications service available on the Internet. The concept of sending electronic text messages between parties in a way analogous to mailing letters or memos predates the creation of the Internet. Today it can be important to distinguish between internet and internal e-mail systems. Internet e-mail may travel and be stored unencrypted on many other networks and machines out of both the sender's and the recipient's control. During this time it is quite possible for the content to be read and even tampered with by third parties, if anyone considers it important enough. Purely internal or intranet mail systems, where the information never leaves the corporate or organization's network, are much more secure, although in any organization there will be IT and other personnel whose job may involve monitoring, and occasionally accessing, the e-mail of other employees not addressed to them. Pictures, documents and other files can be sent as e-mail attachments. E-mails can be cc-ed to multiple e-mail addresses.
Internet telephony is another common communications service made possible by the creation of the Internet. VoIP stands for Voice-over-Internet Protocol, referring to the protocol that underlies all Internet communication. The idea began in the early 1990s with walkie-talkie-like voice applications for personal computers. In recent years many VoIP systems have become as easy to use and as convenient as a normal telephone. The benefit is that, as the Internet carries the voice traffic, VoIP can be free or cost much less than a traditional telephone call, especially over long distances and especially for those with always-on Internet connections such as cable or ADSL. VoIP is maturing into a competitive alternative to traditional telephone service. Interoperability between different providers has improved and the ability to call or receive a call from a traditional telephone is available. Simple, inexpensive VoIP network adapters are available that eliminate the need for a personal computer.
Voice quality can still vary from call to call but is often equal to and can even exceed that of traditional calls. Remaining problems for VoIP include emergency telephone number dialling and reliability. Currently, a few VoIP providers provide an emergency service, but it is not universally available. Traditional phones are line-powered and operate during a power failure; VoIP does not do so without a backup power source for the phone equipment and the Internet access devices. VoIP has also become increasingly popular for gaming applications, as a form of communication between players. Popular VoIP clients for gaming include Ventrilo and Teamspeak. Wii, PlayStation 3, and Xbox 360 also offer VoIP chat features.
Data transfer
File sharing is an example of transferring large amounts of data across the Internet. A computer file can be e-mailed to customers, colleagues and friends as an attachment. It can be uploaded to a website or FTP server for easy download by others. It can be put into a "shared location" or onto a file server for instant use by colleagues. The load of bulk downloads to many users can be eased by the use of "mirror" servers or peer-to-peer networks. In any of these cases, access to the file may be controlled by user authentication, the transit of the file over the Internet may be obscured by encryption, and money may change hands for access to the file. The price can be paid by the remote charging of funds from, for example, a credit card whose details are also passed—usually fully encrypted—across the Internet. The origin and authenticity of the file received may be checked by digital signatures or by MD5 or other message digests. These simple features of the Internet, over a worldwide basis, are changing the production, sale, and distribution of anything that can be reduced to a computer file for transmission. This includes all manner of print publications, software products, news, music, film, video, photography, graphics and the other arts. This in turn has caused seismic shifts in each of the existing industries that previously controlled the production and distribution of these products.
Streaming media refers to the act that many existing radio and television broadcasters promote Internet "feeds" of their live audio and video streams (for example, the BBC). They may also allow time-shift viewing or listening such as Preview, Classic Clips and Listen Again features. These providers have been joined by a range of pure Internet "broadcasters" who never had on-air licenses. This means that an Internet-connected device, such as a computer or something more specific, can be used to access on-line media in much the same way as was previously possible only with a television or radio receiver. The range of material is much wider, from pornography to highly specialized, technical webcasts. Podcasting is a variation on this theme, where—usually audio—material is downloaded and played back on a computer or shifted to a portable media player to be listened to on the move. These techniques using simple equipment allow anybody, with little censorship or licensing control, to broadcast audio-visual material worldwide.
Webcams can be seen as an even lower-budget extension of this phenomenon. While some webcams can give full-frame-rate video, the picture is usually either small or updates slowly. Internet users can watch animals around an African waterhole, ships in the Panama Canal, traffic at a local roundabout or monitor their own premises, live and in real time. Video chat rooms and video conferencing are also popular with many uses being found for personal webcams, with and without two-way sound. YouTube was founded on 15 February 2005 and is now the leading website for free streaming video with a vast number of users. It uses a flash-based web player to stream and show video files. Registered users may upload an unlimited amount of video and build their own personal profile. YouTube claims that its users watch hundreds of millions, and upload hundreds of thousands, of videos daily.
Accessibility
The prevalent language for communication on the Internet is English. This may be a result of the origin of the Internet, as well as English's role as a lingua franca. It may also be related to the poor capability of early computers, largely originating in the United States, to handle characters other than those in the English variant of the Latin alphabet. After English (29% of Web visitors) the most requested languages on the World Wide Web are Chinese (22%), Spanish (8%), Japanese (6%), French (5%), Portuguese and German (4% each), Arabic (3%) and Russian and Korean (2% each). By region, 42% of the world's Internet users are based in Asia, 24% in Europe, 15% in North America, 11% in Latin America and the Caribbean taken together, 4% in Africa, 3% in the Middle East and 1% in Australia/Oceania. The Internet's technologies have developed enough in recent years, especially in the use of Unicode, that good facilities are available for development and communication in most widely used languages. However, some glitches such as mojibake (incorrect display of foreign language characters, also known as kryakozyabry) still remain.
Common methods of Internet access in homes include dial-up, landline broadband (over coaxial cable, fiber optic or copper wires), Wi-Fi, satellite and 3G technology cell phones. Public places to use the Internet include libraries and Internet cafes, where computers with Internet connections are available. There are also Internet access points in many public places such as airport halls and coffee shops, in some cases just for brief use while standing. Various terms are used, such as "public Internet kiosk", "public access terminal", and "Web payphone". Many hotels now also have public terminals, though these are usually fee-based. These terminals are widely accessed for various usage like ticket booking, bank deposit, online payment etc. Wi-Fi provides wireless access to computer networks, and therefore can do so to the Internet itself. Hotspots providing such access include Wi-Fi cafes, where would-be users need to bring their own wireless-enabled devices such as a laptop or PDA. These services may be free to all, free to customers only, or fee-based. A hotspot need not be limited to a confined location. A whole campus or park, or even an entire city can be enabled. Grassroots efforts have led to wireless community networks. Commercial Wi-Fi services covering large city areas are in place in London, Vienna, Toronto, San Francisco, Philadelphia, Chicago and Pittsburgh. The Internet can then be accessed from such places as a park bench. Apart from Wi-Fi, there have been experiments with proprietary mobile wireless networks like Ricochet, various high-speed data services over cellular phone networks, and fixed wireless services. High-end mobile phones such as smartphones generally come with Internet access through the phone network. Web browsers such as Opera are available on these advanced handsets, which can also run a wide variety of other Internet software. More mobile phones have Internet access than PCs, though this is not as widely used. An Internet access provider and protocol matrix differentiates the methods used to get online.
Social impact
The Internet has made possible entirely new forms of social interaction, activities and organizing, thanks to its basic features such as widespread usability and access. Social networking websites such as Facebook and MySpace have created a new form of socialization and interaction. Users of these sites are able to add a wide variety of items to their personal pages, to indicate common interests, and to connect with others. It is also possible to find a large circle of existing acquaintances, especially if a site allows users to utilize their real names, and to allow communication among large existing groups of people. Sites like meetup.com exist to allow wider announcement of groups which may exist mainly for face-to-face meetings, but which may have a variety of minor interactions over their group's site at meetup.org, or other similar sites.
The first generation is now being raised with widespread availability of Internet connectivity, with consequences for privacy, identity, and copyright concerns. These "Digital natives" face a variety of concerns that were not present for prior generations.
In democratic societies, the Internet has achieved new relevance as a political tool, leading to Internet censorship by some states. The presidential campaign of Howard Dean in 2004 in the United States became famous for its ability to generate donations via the Internet. Many political groups use the Internet to achieve a whole new method of organizing, in order to carry out Internet activism. Some governments, such as those of Iran, North Korea, Myanmar, the People's Republic of China, and Saudi Arabia, restrict what people in their countries can access on the Internet, especially political and religious content. This is accomplished through software that filters domains and content so that they may not be easily accessed or obtained without elaborate circumvention.
In Norway, Denmark, Finland and Sweden, major Internet service providers have voluntarily (possibly to avoid such an arrangement being turned into law) agreed to restrict access to sites listed by police. While this list of forbidden URLs is only supposed to contain addresses of known child pornography sites, the content of the list is secret. Many countries, including the United States, have enacted laws making the possession or distribution of certain material, such as child pornography, illegal, but do not use filtering software. There are many free and commercially available software programs, called content-control software, with which a user can choose to block offensive websites on individual computers or networks, such as to limit a child's access to pornography or violence.
The Internet has been a major source of leisure since before the World Wide Web, with entertaining social experiments such as MUDs and MOOs being conducted on university servers, and humor-related Usenet groups receiving much of the main traffic. Today, many Internet forums have sections devoted to games and funny videos; short cartoons in the form of Flash movies are also popular. Over 6 million people use blogs or message boards as a means of communication and for the sharing of ideas. The pornography and gambling industries have both taken full advantage of the World Wide Web, and often provide a significant source of advertising revenue for other websites. Although many governments have attempted to put restrictions on both industries' use of the Internet, this has generally failed to stop their widespread popularity.
One main area of leisure on the Internet is multiplayer gaming. This form of leisure creates communities, bringing people of all ages and origins to enjoy the fast-paced world of multiplayer games. These range from MMORPG to first-person shooters, from role-playing games to online gambling. This has revolutionized the way many people interact and spend their free time on the Internet. While online gaming has been around since the 1970s, modern modes of online gaming began with services such as GameSpy and MPlayer, to which players of games would typically subscribe. Non-subscribers were limited to certain types of game play or certain games. Many use the Internet to access and download music, movies and other works for their enjoyment and relaxation. As discussed above, there are paid and unpaid sources for all of these, using centralized servers and distributed peer-to-peer technologies. Some of these sources take more care over the original artists' rights and over copyright laws than others.
Many use the World Wide Web to access news, weather and sports reports, to plan and book holidays and to find out more about their random ideas and casual interests. People use chat, messaging and e-mail to make and stay in touch with friends worldwide, sometimes in the same way as some previously had pen pals. Social networking websites like MySpace, Facebook and many others like them also put and keep people in contact for their enjoyment. The Internet has seen a growing number of Web desktops, where users can access their files, folders, and settings via the Internet. Cyberslacking can become a serious drain on corporate resources; the average UK employee spent 57 minutes a day surfing the Web while at work, according to a 2003 study by Peninsula Business Services.