"Earth, man... What a shithole."
Ron Johner (from Alien Resurrection)

Earth, often referred to as the world, was the third planet in the Sol System. It was a terrestrial planet, being both the densest planet in the system and the largest of the system's four terrestrial planets. Earth was the homeworld of the human species and, as such, was the seat of power for major human governments including the Three World Empire, the Union of Progressive Peoples, and the United Americas. Earth was orbited by one moon, Luna, which was the first astronomical body beyond Earth to be colonized by humans.



Earth was formed by accretion when excess matter from its parent stars' genesis began clumping together into planets and moons. Its basalt crust cooled soon after its formation and collision with the protoplanet Theia. Its gasses appeared via outgassing, where volcanoes produce volatile gasses such as oxygen and nitrogen.

Its extensive bodies of water were produced from comets and other water-rich bodies crashing down on its surface.


The earliest life on Earth arose at least 3.5 billion years ago when a Sacrifice Engineer consumed a vial of unknown liquid, which caused it's body to dissolve, releasing his genetic code into the Earth's biosphere for eventual development into life. Earth's biodiversity expanded continually except when interrupted by mass extinctions. Although scholars estimated that over 99% of all species of life (over 5 billion) that ever lived on Earth were extinct, there were still an estimated 10–14 million extant species, of which about 1.2 million had been documented and over 86% had not yet been described.

Later human development[]

Over 7.3 billion humans live on Earth and depend on its biosphere and minerals for their survival. Earth's human population is divided among about two hundred sovereign states which interact through diplomacy, conflict, travel, trade, communication, and media. By the early 22nd century, Antarctica hosted a major air traffic control station for departing and returning interstellar commercial vessels. One of their clients included Weyland-Yutani for the purpose of guiding mineral ore bulk freighters from distant worlds to the Earth. The station's radio signals had a limited range away from the Earth and could not be heard outside of the Solar System.

During the year 2381, most of the people who lived on Earth were mostly made up of disenfranchised and unemployed people, as most of the meaningful work now took place in space and the colonies.[1]

Geographical Features[]

As the homeworld of the Human species, Earth is the archetype by which they measure all other planets in terms of habitability. The ultimate goal of all terraforming efforts across the galaxy is to create an environment similar to that of Earth on any planet the humans attempt to colonize.

Earth is approximately 4.5 billion years old. It possesses an iron core that is solid at its center with a liquid layer encompassing it. This generates a powerful magnetosphere that has kept Earth from losing its water and other volatile organic compounds. The core is surrounded by semifluid magma, on which the solid, yet light crust floats. The planet is geologically active, with plate tectonics causing volcanoes and natural springs to dot its surface. Earthquakes are common.

The planet lies in the liquid water zone of Sol, and water is found in abundance-oceans cover 70% of the planet. The 30% of the surface that is dry land is divided amongst four major landmasses, which are subsequently divided into seven continents (from largest in area to smallest: Asia, Africa, North America, South America, Antarctica, Europe, and Australasia), along with thousands of islands spread across the oceans. There is a thin atmosphere that is maintained by the biomass on the planet's surface. It is 78% nitrogen and 21% oxygen, with the remainder a mix of trace gases including argon, carbon dioxide and water vapor.

Earth spins on its axis once every 23 hours, 56 minutes, 4 seconds. The axis is tilted 23° from its orbital plane, which causes seasonal changes in its higher latitudes as it orbits Sol.

Earth held an abundance of natural resources well into the 22nd century, such as minerals and several substances produced as by-products by the planet's biomass, such as petroleum, coal, wood, and natural gas. Humans utilized these resources into an impressive technology base. However, over time the resources of Earth began to become exhausted, prompting Humans to search for other worlds which could be exploited.

Terrain and climate[]

The geological activity of Earth has created a wide variety of terrain across its surface. Plate tectonics and erosion (by both the atmosphere and water) dominate the formation processes of surface features. There are mountain ranges, valleys, plains, mesas, and canyons, which in turn may be found in deserts, tundra, forests, grasslands, and icecaps at the poles. Earth may be classified into three general climate zones: the tropics, which straddle each side of the Equator, the polar regions located around the North and South Poles, and the temperate zones in-between. Each of these are divided into other zones which vary depending on the distance from the Equator, proximity to large bodies of water, and local geography, such as mountains.

Humans began to modify the terrain of Earth when they discovered agriculture around 8000 BCE. This enabled the development of great cities linked by trade routes stretching for thousands of miles over both land and ocean. Beginning in the 19th century, Humans began to alter the planetary climate with the introduction of industrial by-products. As early as the second-half of the 21st Century Earth's environment began to significantly degrade, but remained habitable well into the 22nd Century. By the 24th century, much of Earth had become an arid wasteland. But over time, by the time of Alien Resurrection, It seems that there have been efforts to restore the Earth's ecology in some areas.



Semi-sentient and non-sentient[]


Notable locations that have been the site of Xenomorph, Engineer and Predator activity:


North America[]

Central and South America[]




Middle East[]



  • Gateway Station is in permanent orbit around Earth.
  • In the unofficial Alien sequel, Alien 2: On Earth, the Aliens take over the Earth, as suggested by the film's "you may be next!" message. The conquest of Earth by the Xenomorphs is also a major plot point in many of the comics and novels of the Alien franchise.
  • It is heavily insinuated in Alien Resurrection that some kind of catastrophe, or simply years of degradation, have made Earth uninhabitable or at least very unpleasant. At the end of the extended Special Edition of the movie, it is shown that Paris, France is in ruins, while the surrounding area is a desolate wasteland. The devastation may have something to do with the "Lacerta Plague", which is mentioned in the film by Annalee Call. However, Earth does not appear to have been entirely abandoned — the planet remains the designated home base of the USM Auriga. Johner's comment that Earth is "a shithole" by this time seems to imply that centuries of pollution, war and resource depletion have left Earth in a dilapidated state.
  • In several novels and comics of the Alien franchise, all of humanity on Earth has been portrayed as being united under the authority of a single Terran government.
  • In Alien Resurrection, when the Auriga hits Earth, a large blast wave can be seen. The wave would have killed almost all life in central Africa.