Earth (aka Terra) is the third planet orbiting the Sun, an average yellow-dwarf star near the outer rim of the Milky Way galaxy, and is the only known planet that supports life. It has a single, very large natural satellite referred to as "the Moon".
Earth figures prominently as the homeworld of the human species in a great number of science-fiction stories, shows, movies, and books.
Earth in Science Fiction
In Star Trek, Earth is the capital of the United Federation of Planets and the center of most of the Federation's research and manufacturing facilities, especially those related to Starfleet. Despite Earth's importance to the Federation, the system is frequently left virtually undefended.
In Stargate, humans from Earth have been transplanted throughout the galaxy by alien races.
In Warhammer 40,000, Earth is known as Holy Terra and is the Capital of the Imperium of Man, with most of it's surface being covered by various cities. The most important structure is the Imperial Palace, home of the Emperor.
Notes and References
- The average parameters of the core, mantle, and crust, as well as the gravitational binding energy, are based on the isotropic PREM model of Dziewonski and Anderson.
- Dziewonski, A.M. and D.L. Anderson. Preliminary Reference Earth Model (PREM), Phys. Earth Planet. Inter. 25, 297-356, 1981.
- Williams, David R. "Earth Fact Sheet"