Sol system

The Sol System, otherwise referred to by UNSC personnel and Humans alike as the Solar System, is the home star system for Humans. The system's G-class star is named Sol, hence the system's name.

Major Planets and Moons

 * Mercury
 * Venus
 * Earth - The Human/UNSC Headquarters (HQ)/Homeworld.
 * Luna
 * Mars - A major site of the Interplanetary War and later during the Human-Covenant War it was the site of 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 detects 15 Covenant ships inbound under the command of the Prophet of Regret.
 * Europa - It contains a UNSC base. Spartans Linda and Will were once assigned to a mission on this satellite.
 * Callisto - The Second Largest Jovian Moon. Herzog claimed to have to deal with paperwork regarding surveillance here.
 * Ganymede - The EVA Armor was developed here.
 * 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.
 * Uranus - An icy gas giant about twice as far away as Saturn from Sol.
 * Neptune - Furthest away from Sol, it is another icy gas giant similar to Uranus.

Dwarf Planets

 * Ceres - The largest asteroid to have ever been discovered by humanity.
 * Eris - Currently the largest Dwarf Planet known. It is almost 10% larger than Pluto in diameter.
 * Pluto - In the 1930's, Pluto was discovered and named a planet. Many years later in 2006, scientists debated over if it was really big enough to actually be considered a planet, and after much talk, it was declassified. 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 three moons: Nix, Hydra, and Charon

Trivia

 * Sol is the original Latin and the actual scientific name for Earth's Sun. The designation and name has actually been used instead of "Solar System" in many Sci-fi novels.

Links
Halo Mapping Project