An island continent between the Indian and Pacific Oceans on Old Earth. It is the smallest on Old Earth, with an area of 8,560,000 square kilometres, and it was not well suited to long term agricultural uses, so it did not contain any major civilizations or polities until the Industrial Age. After several centuries of sustained immigration, Australia became a prosperous nation, and was an important power on Earth during much of the Interplanetary Age.
Australia was originally part of Gondwana, and contains some of the oldest and least geologically active portions of that ancient supercontinent. By the start of the Holocene epoch around 11,600 BT, when humans were predominant on the planet, it was mostly flat, with soils lacking in some important minerals. It was also arid, due to its latitude, though it was lush and green during the preceding epochs. Australia was populated by a distinct marsupial fauna.
Human habitation of Australia dates back to about 40,000 BT, but for most of human history the continent was a relative backwater due to its isolation, uncertain climate, and impoverished soils, and its inhabitants employed Palaeolithic technologies. The indigenous population suffered greatly at the hands of the European colonists who arrived during the Industrial Age; their cultures were almost entirely destroyed, and their descendants became a small fraction of the continent's total population. By the time Australia achieved independence from Britain in the late Industrial Age, the continent had united into a democraticconstitutional monarchy. Becoming active in world affairs during the 20th century CE, Australia was a founding member of the United Nations and developed an enduring alliance with the United States.
During the 1st century AT, Australia became a republic and created a few manned stations in Earth orbit and a lunar habitat that would eventually become Perth on the Serenitatis. By the late 2nd century AT the originally largely European population had been greatly influenced by Asian immigration, mostly from Indonesia, Malaysia, and China. Australia witnessed the construction of a multitude of arcologies and closed habitats in its once sparsely populated interior, the "Out Back", that helped house its burgeoning population and protect it from the then harsh effects of climate change. New envirotech systems propagated by the rise of the Technocratic-Green Party during the 3rd century AT furthered environmental renewal, as seen by the eventual restoration of the Great Barrier Reef.
In the centuries before the Technocalypse, Australia developed a robust interplanetary policy, establishing a number of colonies throughout the solar system. Significant settlements include the Botany Bay Bubblehabs on Venus, New Darwin on Mars, Adelaide Station in the belt, and Oliphant Depot orbiting Iapetus. Commanded by Stephanie Awang, the Australian ship Wagyl became the first human crewed mission to reach Uranus in 243 AT. Australians, with their often distinctive Eurasian features and charmingly annoying "ockerisms", remained an important element of off-world culture. Australia proved a vibrant member of the Council of Earth and a cornerstone of the League of the Americas and Australasia.
During the Interplanetary and Solsys Golden ages, the capital of Australia, Canberra, was an important center of learning, and was known as "the Geneva of the South". Thanks to blue goo defenses it survived the Technocalypse largely intact, but the vast majority of the population was finally forced into exodus, along with most of the rest of humanity, by GAIA during the Great Expulsion. The city has since been completely dismantled, except for a few research sites of historical value preserved by GAIA. The rest of Australia has been returned to its pre-European condition excluding a few points of interest such as the Sydney Opera House and certain sections of the Melbourne subterranean arcology. The remaining sapient population would seem to consist solely of a small number of genomically-restored aboriginal caretakers, mostly biochip enhanced and rianthed with indigenous fauna, and a number of marsupial and reptilian provolves (chiefly Roos and neo-Goannas). Off Earth, few traces of Australian culture remain in the current era. Notable exceptions include the Hider clade known as the Drovers and the low-tech world Uluru ruled by the S2 entity Tingari. Canberra Orbital in the Communion of Worlds is named after the continent's former capital.