The Asteroid Belt, often referred to as The Belt, also known as the main asteroid belt (to distinguish it from the farther out Kuiper belt), is a torus-shaped region in the Sol system, located roughly between the orbits of Mars and Jupiter. It consists of numerous smaller and bigger asteroids, and is part of the outer planets region of the system.
The four biggest asteroids of the belt, Ceres, Vesta, Pallas, and Hygiea, contain half of its overall mass. In total, the mass of all objects in the asteroid belt is approx. 4% that of Luna, or roughly twice that of Charon, and is estimated to be around 2.39 × 1021 kg. The size of objects in the belt varies from small rocks up to dwarf planets. The temperatures depend on the distance from the sun and typically range from -73 — -108 °C.
The Belt was colonized by humans roughly in the 2200s, after the invention of the Epstein Drive by the Martian engineer Solomon Epstein. In exchange for their independence, Mars thereafter shared the Epstein-technology with Earth, leading to the exploitation of resources and later to colonization of asteroids and moons in the belt and the outer system by the two superpowers. People born on the colonized asteroids are called Belters.