Sol system

The Sol system, also referred to as the Sol star system, is the home star system of the human species. Earth, the human homeworld, holds the seat of power for both the Unified Earth Government, and the United Nations Space Command.

Planetary system

 * Mercury - Tiny, barren world.
 * Venus - Failed terraforming project.
 * Earth - The human homeworld, home to the headquarters of the UEG and the UNSC. Also the site of Kupiga Simu, a Sol system communications transmitter.
 * Luna - Earth's only natural satellite. Home to Sol's oldest Officer Candidate School, the famed Luna OCS Academy.
 * Mars - Humanity's first colonized planet and terraformed to have an Earth-like climate.
 * Phobos - Site of a Penal colony.
 * Jupiter - A gas giant, and second largest body in the Sol System.
 * Io - Unstable moon with a large colony.
 * Europa - Colonized and terraformed.
 * Callisto - Home to a number of UNSC bases.
 * Ganymede - Largest moon of Jupiter, partially terraformed, and is populated.
 * Saturn - A gas giant known for its bright surrounding rings. Saturn is the third largest body in the Sol System. Its practical uses to the UNSC are limited, and therefore it is mostly just a tourist destination. Castellaneta, a tourist station, is in geosynchronous orbit on the "sunny side" of the planet's outermost ring.
 * Titan - Industrial colony.
 * Enceladus
 * Uranus - Gas giant with anomalous properties.
 * 2011 QF99 - One of Uranus' trojan asteroids, it features an anomaly of some kind and is surrounded by an exclusion zone.
 * Neptune - Named after the Roman god of the sea. Furthest away from Sol, it is a gas giant that is relatively unexplored.
 * Kuiper Belt
 * Pluto - A diminutive planetoid once classified as a planet. Numerous space stations orbit it.
 * Shaw Institute Facility
 * Oort cloud

Post-Great Purification
Humanity first colonized the system's worlds beyond Earth in the late 21st and early 22nd centuries, followed by steady growth of the populations on Earth and the off-world colonies throughout the next two centuries before the launch of the first extrasolar colonization program in 2362, enabled by the development of the Shaw-Fujikawa Translight Engine in 2291.

Attacks on the system
The first known incursion into the Sol System was on October 10, 2552 by unknown enemies.

On October 20, the Fleet of Sacred Consecration was detected near the moon of Io. Soon after, the Fleet appeared near Earth, commencing the Battle for Earth. Over the next few months, battles on Earth and elsewhere in the system would take place. The Battle of Mare Erythraeum on Mars would take place during this time frame. The UNSC Home Fleet would be utterly devastated by November 17 with the arrival of the Anodyne Spirit and Truth's fleet. One of final skirmishes on Earth would take place on December 3, during Operation: MARSH FLASH.

Despite massive Covenant assault across the Sol system even on Sol colonies' cities, many of the human population centers of Sol colonies, such as Mars, and Luna in the system survived the assault relatively intact, although the majority of Earth habitats has been destroyed. In aftermath of the Battle for Tribute with the loss of over half of the population on Tribute, Earth was unable to afford to spare any immediate assistance with Sol’s colonies that has been left in ruins during the Covenant onslaught on the Sol system.

Trivia

 * Sol is the original Latin and the actual scientific name for Earth's sun. This designation and name has actually been used instead of "Solar System" in many science fiction novels.
 * Sol is also an emblem option in Halo 3 and Halo: Reach.
 * It is possible the human colony Ixion is 28978 Ixion, a minor planet in the Kuiper belt in the Sol system that was first discovered in 2001.

List of appearances

 * Halo: The Fall of Reach
 * Halo: First Strike
 * i love bees
 * Halo 2
 * Halo Graphic Novel
 * Halo: Ghosts of Onyx
 * Iris
 * Halo 3: The Cradle of Life
 * Halo: Landfall
 * Halo: Combat
 * Halo: Last One Standing
 * Halo: Uprising
 * Halo 3
 * Halo: Contact Harvest
 * Halo: The Cole Protocol
 * Halo Wars
 * Halo 3: ODST
 * Halo Legends
 * Origins
 * Halo: Evolutions - Essential Tales of the Halo Universe
 * Midnight in the Heart of Midlothian
 * Palace Hotel
 * The Impossible Life and the Possible Death of Preston J. Cole


 * Halo: Cryptum
 * Halo: Glasslands
 * Halo: Combat Evolved Anniversary
 * ''Terminals
 * Halo: The Thursday War
 * Halo 4
 * Spartan Ops
 * Halo: Silentium
 * Halo: Escalation
 * Halo 2: Anniversary
 * Terminals
 * Halo: New Blood
 * Halo: Spartan Strike
 * Halo: Hunters in the Dark
 * Halo: Fleet Battles
 * Halo: Ground Command
 * Halo Mythos
 * Halo: Bad Blood