The Commonwealth of Australia is a country in the southern hemisphere comprising the mainland of the world's smallest continent, the major island of Tasmania and a number of other islands in the Indian, Pacific and Southern Oceans.N4 The neighbouring countries are Indonesia, East Timor and Papua New Guinea to the north, the Solomon Islands, Vanuatu and New Caledonia to the north-east, and New Zealand to the south-east.

The Australian mainland has been inhabited for more than 42,000 years by Indigenous Australians. After sporadic visits by fishermen from the north and by European explorers and merchants starting in the 17th century, the eastern half of Australia was claimed by the British in 1770 and initially settled through penal transportation as part of the colony of New South Wales, commencing on 26 January 1788. As the population grew and new areas were explored, another five largely self-governing Crown Colonies were established during the 19th century.

On 1 January 1901, the six colonies became a federation, and the Commonwealth of Australia was formed. Since federation, Australia has maintained a stable liberal democratic political system and remains a Commonwealth Realm. The capital city is Canberra, located in the Australian Capital Territory. The population is 21 million, and is concentrated in the mainland state capitals of Sydney, Melbourne, Brisbane, Perth, and Adelaide.

Politics

The Commonwealth of Australia is a constitutional monarchy with a parliamentary system of government. Queen Elizabeth II is the Queen of Australia, a role that is distinct from her position as monarch of the other Commonwealth realms. The Queen is represented by the Governor-General at Federal level and by the Governors at State level. Although the Constitution gives extensive executive powers to the Governor-General, these are normally exercised only on the advice of the Prime Minister. The most notable exercise of the Governor-General's reserve powers outside the Prime Minister's direction was the dismissal of the Whitlam Government in the constitutional crisis of 1975.

There are three branches of government:
The legislature: the Commonwealth Parliament, comprising the Queen, the Senate, and the House of Representatives; the Queen is represented by the Governor-General, whose powers are limited to assenting to laws.
The executive: the Federal Executive Council (the Governor-General as advised by the Executive Councillors); in practice, the councillors are the Prime Minister and Ministers of State.
The judiciary: the High Court of Australia and other federal courts. The State courts became formally independent from the Judicial Committee of the Privy Council when the Australia Act was passed in 1986.

The bicameral Commonwealth Parliament consists of the Queen, the Senate (the upper house) of 76 senators, and a House of Representatives (the lower house) of 150 members. Members of the lower house are elected from single-member constituencies, commonly known as 'electorates' or 'seats'. Seats in the House of Representatives are allocated to states on the basis of population, with each original state guaranteed a minimum of five seats. In the Senate, each state is represented by 12 senators, and the territories (the ACT and the NT) by two. Elections for both chambers are held every three years; Senators have overlapping six-year terms, and only half of the seats are put to each election unless the cycle is interrupted by a double dissolution. The party with majority support in the House of Representatives forms government, and its leader becomes Prime Minister.

There are three major political parties: the Australian Labor Party, the Liberal Party and the National Party. Independent members and several minor parties — including the Greens and the Australian Democrats — have achieved representation in Australian parliaments, mostly in upper houses. Since the 1996 election, the Liberal/National Coalition led by the Prime Minister, John Howard, has been in power in Canberra. In the 2004 election, the Coalition won control of the Senate - the first time in more than 20 years that a party (or coalition) has done so while in government. The Labor Party is in power in every state and territory. Voting is compulsory for all enrolled citizens 18 years and over in each state and territory and at the federal level; such enrolment is compulsory in all jurisdictions but South Australia.

States and territories

Australia consists of six states, two major mainland territories, and other minor territories. The states are New South Wales, Queensland, South Australia, Tasmania, Victoria and Western Australia. The two major mainland territories are the Northern Territory and the Australian Capital Territory. In most respects, the territories function similarly to the states, but the Commonwealth Parliament can override any legislation of their parliaments. By contrast, federal legislation overrides state legislation only with respect to certain areas as set out in Section 51 of the Constitution; all residual legislative powers are retained by the state parliaments, including powers over hospitals, education, police, the judiciary, roads, public transport and local government.

Each state and territory has its own legislature, which are unicameral in the case of the Northern Territory, the ACT and Queensland, and bicameral in the remaining states. The lower house is known as the Legislative Assembly (House of Assembly in South Australia and Tasmania) and the upper house is known as the Legislative Council. The heads of the governments in each state and territory are called premiers and chief ministers, respectively. The Queen is represented in each state by a governor; an administrator in the Northern Territory, and the Governor-General in the ACT, have analogous roles.

Australia also has several minor territories; the federal government administers a separate area within New South Wales, the Jervis Bay Territory, as a naval base and sea port for the national capital. In addition Australia has the following, inhabited, external territories: Norfolk Island, Christmas Island, Cocos (Keeling) Islands, and several largely uninhabited external territories: Ashmore and Cartier Islands, Coral Sea Islands, Heard Island and McDonald Islands and the Australian Antarctic Territory.

Foreign relations and the military

Over recent decades, Australia's foreign relations have been driven by a close association with the United States through the ANZUS pact, and by a desire to develop relationships with Asia and the Pacific, particularly through ASEAN and the Pacific Islands Forum. In 2005 Australia secured an inaugural seat at the East Asia Summit following its accession to the Treaty of Amity and Cooperation. Australia is a member of the Commonwealth of Nations, in which the Commonwealth Heads of Government meetings provide the main forum for co-operation. Australia has energetically pursued the cause of international trade liberalisation. Australia led the formation of the Cairns Group and APEC, and is a member of the OECD and the WTO. Australia has pursued several major bilateral free trade agreements, most recently the Australia-United States Free Trade Agreement. Australia is a founding member of the United Nations, and maintains an international aid programme under which some 60 countries receive assistance. The 2005–06 budget provides A$2.5 bn for development assistance; as a percentage of GDP, this contribution is less than that of the UN Millennium Development Goals.

Australia's armed forces — the Australian Defence Force (ADF) — comprise the Royal Australian Navy (RAN), the Australian Army, and the Royal Australian Air Force (RAAF), numbering about 51,000. All branches of the ADF have been involved in UN and regional peacekeeping (most recently in East Timor, the Solomon Islands and Sudan), disaster relief, and armed conflict, including the 2003 Invasion of Iraq. The government appoints the Chief of the Defence Force from one of the armed services; the current Chief of the Defence Force is Air Chief Marshal Angus Houston. In the 2006–07 Budget, defence spending is A$22 bn.

Geography

Australia's 7,617,930 square kilometres (2,941,299 sq. mi) landmass is on the Indo-Australian Plate. Surrounded by the IndianN4 and Pacific oceans, Australia is separated from Asia by the Arafura and Timor seas. Australia has a total 34,218 kilometres (21,262 mi) of coastline (excluding all offshore islands) and claims an extensive Exclusive Economic Zone of 8,148,250 square kilometres (3,146,057 sq. mi). This exclusive economic zone does not include the Australian Antarctic Territory.

The Great Barrier Reef, the world's largest coral reef, lies a short distance off the north-east coast and extends for over 2,000 kilometres (1,250 mi). Mount Augustus claimed to be the world's largest monolith, is located in Western Australia. At 2,228 metres (7,310 ft), Mount Kosciuszko on the Great Dividing Range is the highest mountain on the Australian mainland, although Mawson Peak on the remote Australian territory of Heard Island is taller at 2,745 metres (9,006 ft).

By far the largest part of Australia is desert or semi-arid. Australia is the flattest continent, has the oldest and least fertile soils, and is the driest inhabited continent. Only the south-east and south-west corners of the continent have a temperate climate. Most of the population lives along the temperate south-eastern coastline. The landscapes of the northern part of the country, with a tropical climate, consist of rainforest, woodland, grassland, mangrove swamps and desert. The climate is significantly influenced by ocean currents, including the El NiƱo southern oscillation, which is correlated with periodic drought, and the seasonal tropical low pressure system that produces cyclones in northern Australia.