|Desert / Rock / Cave
|30 standard hours
|256 standard days
Geonosis is located in the Geonosis system. It is the homeworld of the Geonosian race.
In the distant past, Geonosis's largest moon was hit by a rogue comet, sending out a massive debris field, which hammered the surface into ruin before settling into a ring of orbiting rock. This event killed off many of Geonosis's native species.
Most of the arid surface of Geonosis consists of hills, plateaus and great rocky outcroppings. For most species, life on the planet is extremely difficult. Because the planet's magnetic field is weak, solar rays reach the surface without any filter, and the world is exposed to aggressive waves of radiation. The potency of the sun around the planet is so great that harmful particles affect the surface even at night.
The only relief for the native species comes with the long periods of darkness caused by dense fog that can linger for weeks. In these periods, the high, dense fog banks act as a barrier for the aggressive sunlight, and provide the planetary surface with a gloomy, rather eerie appearance. During these periods, some of the planets' creatures creep out of their lairs in the search for food or for mates. Some of the native beings have developed bioluminescent properties enabling them to adapt to the harsh environment. One of the more spectacular, natural phenomena of Geonosis is the abundant rain that falls on the planet.
The rainfall occurs only very rarely, but when it does it usually causes huge flooding. The planet's magnificent canyons and cliffs are living proof of the erosion caused by these powerful downpours. Among the desolate features of the landscape are peculiar spires rising high above the ground. These are, in fact, the only visible parts of the huge underground hive-colonies where the Geonosians live. These intelligent, insectoid beings live in complex maze-like dwellings that extend for thousands of metres underground. These structures imitate the natural forms of the surrounding terrain and so merge perfectly with the arid landscape. Most Geonosian creatures are reptilian or insectoid in form. Among its life-forms are the massifs - huge, dog-like reptiles that can also be found on nearby Tatooine. The Geonosians tame these creatures and keep them as pets as well as to keep their hives free of vermin and other intruders. Another Geonosian species is the red rock algae. These micro-organisms cling to the terrain and give the planetary surface its particular hue.
Geonosis had a large diameter but light gravity and dense atmosphere. With a weak magnetic field, harsh solar radiation storms and massive sandstorms were common, and on occasion mass extinctions occurred. The most persistent surface organisms were humble red rock algae while the semi-insectoid Geonosians were driven underground. The planet consisted of a diminutive molten core with a rocky mantle forming a rocky, desert world subject to flash floods that carved great highland canyons. Water made up 5% of the surface. 
During the time of the Geonosian rule, much of the planet's architecture was similar in appearance to termite mounds, consisting of domes and buildings built into caverns and rock spires. Therefore, one could easily mistake Geonosian buildings for natural formations and the planet to be uninhabited, a great asset during war. 
Over millions of years, the few creatures who survived the devastation slowly reclaimed the planet. Random meteor impacts constantly weeded out the weaker species, leaving only the truly cunning, hardy, and ruthless species alive. The Geonosians, the dominant life form on the planet, constituted all three. 
After the technical-minded Geonosians made contact with the galaxy, several droid and weapon foundries were moved to the planet. 
During the time of the Great Galactic War, Geonosis was famous for the gladiatorial games held on the planet. Many of the combatants were Mandalorians, among them a young fighter. He rose to fame, eventually declaring himself the new Mandalore. He allied the Mandalorians with the Sith Empire, striking against the Galactic Republic. 
Years later, after his eventual death at the hands of another Mandalorian, it was revealed that Imperial Intelligence had been infiltrating the gladiatorial arenas around the galaxy as sponsors, managers and gladiators. They had chosen the young Mandalorian as their champion, rigging his fights, using tactics such as drugging the opponent.
Some three thousand five hundred years ago, the Republic evaluated the planet as a possible defense stronghold.