Sol system

The Sol system, otherwise referred to as the Solar System, is the home star system of the human species. The system's G-class star is named Sol, hence the system's name. Sol is an average sized star in its main sequence phase, and is the dominant source of light for Earth. According to current definitions, eight planets and five dwarfs planets orbit it, for a total of 13, including the four inner terrestrial planets and the four gas giants, separated by an asteroid belt. Many smaller planetoids also orbit Sol, and many of the system's planets possess moons of varying size and number, such as Earth's satellite, Luna.

It is most prominently home to Earth, humanity's homeworld and the capital of the Unified Earth Government, as well as many important human colonies which are based on its many planets, moons and asteroids. Many worlds in the system now house habitats suitable for human life, achieved either through extensive terraforming or the use of vacuum-sealed environments. 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.

Some of the system's colonies were attacked by the Covenant during the Battle of Earth in late 2552, although with the Covenant's primary focus on Earth, many of the human habitats survived the assault relatively intact.

Major planets and moons

 * Mercury
 * Venus
 * Earth - The human homeworld, home to the headquarters of the UEG and the UNSC.
 * Luna- Earth's only natural satellite, home to a major human colony as well as the famed Luna OCS Academy.
 * Mars - One of humanity's first interplanetary colonies, Mars has been terraformed to have an Earth-like climate. Was the site of a decisive battle in the Interplanetary Wars. Fell to the Covenant during the Human-Covenant War after the Battle of Mare Erythraeum.
 * Jupiter - A gas giant, Jupiter is the largest planet in the Sol System.
 * Io - The site of a UNSC listening post. On October 20, 2552, the listening post on Io detected 15 Covenant ships inbound under the command of the Prophet of Regret.
 * Europa - It contains a UNSC base and a substantial colony. Spartans Linda-058 and Will-043 were once assigned to a mission on this satellite.
 * Callisto - The second-largest Jovian Moon. The site of the signing of the Callisto Treaty and a number of UNSC bases.
 * Ganymede - The EVA Armor was developed here; also home to a number of colonists.
 * Saturn - A gas giant known for its clearly visible surrounding rings, unlike the other gas giants whose rings are rather dim. Saturn is the second largest planet 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
 * Enceladus
 * Uranus - An icy gas giant about twice as far away as Saturn from Sol. Its distance from Sol makes it of little use to the UNSC.
 * Neptune - Furthest away from Sol, it is another icy gas giant similar to Uranus.

Dwarf planets

 * Ceres - The largest asteroid in the Sol system.
 * Eris - Currently the largest Dwarf Planet known. It is 10 to 26 kilometers larger than Pluto in diameter.
 * Pluto - Originally discovered in the 1930's and initially classified as the Solar System's ninth planet, Pluto was reclassified as a dwarf planet in 2006. The Pluto Slipstream monitoring station Democritus is stationed in orbit around it. On November 3, 2552, the Monitoring Station detected Cortana's signal in Slipspace with Dr. Halsey's message to Lord Hood. Pluto has five moons: Nix, Hydra, Charon, Kerberos, and Styx.
 * Haumea - The most notable feature is its highly elliptical shape.
 * Makemake - The second most distant dwarf planet, at least one moon.

Other

 * Shaw Institute Facility
 * Oort cloud

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.

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: A Guide to the Story of Halo