The Earth is the third planet from the Sun and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets. It is sometimes referred to as the World, the Blue Planet, or by its Latin name, Terra.
Home to millions of species including humans, Earth is currently the only astronomical body where life is known to exist. The planet formed 4.54 billion years ago, and life appeared on its surface within one billion years. Earth's biosphere has significantly altered the atmosphere and other abiotic conditions on the planet, enabling the proliferation of aerobic organisms as well as the formation of the ozone layer which, together with Earth's magnetic field, blocks harmful solar radiation, permitting life on land. The physical properties of the Earth, as well as its geological history and orbit, have allowed life to persist during this period. The planet is expected to continue supporting life for at least another 500 million years.
Earth's outer surface is divided into several rigid segments, or tectonic plates, that migrate across the surface over periods of many millions of years. About 71% of the surface is covered with salt water oceans, the remainder consisting of continents and islands which together have many lakes and other sources of water contributing to the hydrosphere. Liquid water, necessary for all known life, is not known to exist in equilibrium on any other planet's surface. Earth's poles are mostly covered with solid ice (Antarctic ice sheet) or sea ice (Arctic ice cap). The planet's interior remains active, with a thick layer of relatively solid mantle, a liquid outer core that generates a magnetic field, and a solid iron inner core.
Earth interacts with other objects in space, especially the Sun and the Moon. At present, Earth orbits the Sun once every 366.26 times it rotates about its own axis, which is equal to 365.26 solar days, or one sidereal year. The Earth's axis of rotation is tilted 23.4° away from the perpendicular of its orbital plane, producing seasonal variations on the planet's surface with a period of one tropical year (365.24 solar days). Earth's only known natural satellite, the Moon, which began orbiting it about 4.53 billion years ago, provides ocean tides, stabilizes the axial tilt and gradually slows the planet's rotation. Between approximately 3.8 billion and 4.1 billion years ago, numerous asteroid impacts during the Late Heavy Bombardment caused significant changes to the greater surface environment.
Both the mineral resources of the planet, as well as the products of the biosphere, contribute resources that are used to support a global human population. These inhabitants are grouped into about 200 independent sovereign states, which interact through diplomacy, travel, trade, and military action. Human cultures have developed many views of the planet, including personification as a deity, a belief in a flat Earth or in the Earth as the center of the universe, and a modern perspective of the world as an integrated environment that requires stewardship.
The Earth is also the battlefield during the events of many of Tecno Soft's games.
Although the battle begins (and ends) in outer space, the Earth is the main battlefield during the events of Hyper Duel. An evil government tries to take over the world with all the methods possible, including dropping a space colony on the Earth, but the takeover is thwarted by the Buster Gears.
A nuclear shockwave has all but destroyed the entire population of Earth. The remaining humans on the planet were gathered aboard a ship called the Ark by a prophetic man named Noa. After the radiation dissipated, humankind emerged from the Ark and began building thriving civilizations. However, the fledgling civilization came under attack by a culture called Gorn. Gorn was a culture consisting of the embodiment of machines and artificiality. During the nuclear winter, Gorn was sealed beneath the Earth's crust and emerged when the remaining humans came out of the Ark. Humanity must fight back against Gorn, using ancient weapons unearthed by the new civilization and two "Ultimate Destroyers" Hayate and Reppu piloted by Kyo and Forn.
After the events of Blast Wind, it is revealed that the Earth was dying because of the environmental abuses commited by humanity throughout their history. As a result, Noa and his people returned to a simple way of life. During Noa's existence, they found the hability to communicate with the Earth, where they got messages that confirmed the planet's imminent death. In response, Noa's people put their children in suspended animation on a small spaceship. Escorted by Hayate and Reppu, the spaceship begins its long journey into space towards another habitable planet for humanity.Thunder Force series take us to the 3rd planet of our Solar System, where the Space Probe Sekika 3 brought an alien starfighter known by mankind as "Vastian's Steel" or "Vasteel" to the Lunar base of the United Earth Goverment, where the best scientists tried their best for learn about Vasteel, but the alien technology was so advance for human knowledge. So, in the year 2139 they built a large island called Babel, controlled by the most powerful Artificial Intelligence known as the Guardian, with the purpose of dwelve into the mysteries of the Vasteel. The success of Babel's work led humanity to a new technological evolution known as Vasteel Technology, every invention of the 22nd century could be traced from Vasteel, from Superconductors to Heavily ar.-- er... Interstellar Starships for space colonization.
The progress didn't last for too long, in 2150 the Guardian declared the first war against Earth and the human race for unknown reasons, over one third of Earth's population perished on the event known as the First Annihilation. In 2151, the Special Flight squadron "Thunder Force" was formed with the purpose of destroying both Babel and the Guardian. The operation succeeded in the total destruction of the Vasteel, Guardian and heavy damages on Babel.
Little to nothing is known due to the abrupt cancellation of this game, but it is implied that both Earth Side and Galaxy Federation forces will team up to fight the ORN Empire, creating new units like the Fire LEO-05P "Syrinx", Styx Rev.2 and the RVR-03G "Sword Breaker".
In 2161, the ORN Empire somehow learned of Earth and began an invasion on the planet. Despite initially pushing Earth forces back and forcing them to make a stand in the orbit of their home planet, the ORN invasion was ultimately defeated by Earth forces re-augmented at the last minute by restarting the development of Vasteel technology, named "Refined Vasteel Technology", assembling a new Sword Fleet to engage the Volbados Class battleships in orbit, and restarting the RVR program creating the RVR-00 "Phoenix" and the Phoenix Brigandine. In the aftermath of this hard-fought victory, Earth Side forces initiated an operation to link up with the Galaxy Federation and find a way to definitively end the threat of the ORN Empire.