Scadrial is the name of the planet on which the Mistborn trilogy is set. The planet is governed by two gods, Preservation and Ruin, who are referred to as 'slivers of Adonalsium'. Scadrial is inhabited by humans, although the humans of this world are known to have been created by the power of both Preservation and Ruin working in tandem. It is also inhabited by kandra, koloss and Steel Inquisitors, although these races were created artificially via Hemalurgy. Scadrial greatly resembles Earth, although its cultures are unique to it.
Astronomy
Scadrial is located in an unnamed solar system, orbiting around a yellow star that is much like Sol. Once located in a orbit that was perfect for life, Rashek accidently pushed the planet too far from the sun, causing it to freeze, and then pushed it too close, causing it to burn. It remained in this position for a thousand years before being returned to its natural orbit by Sazed. Although the other planets of the solar system are briefly mentioned, no details about them are given. No mention is ever made of a moon orbiting Scadrial, possibly contributing to the brightness of stars as seen from the surface (due to the ever-present mists at night stars are rarely visible to observers anyway).
Geography
Scadrial, as stated, much resembles Earth, being a planet of vast continents and oceans, although for the past thousand years came close to being rendered uninhabitable through the actions of the Lord Ruler and Ruin. By the time of The Well of Ascension life could only flourish in a small area near the poles, as Vin reveals when she holds the power of the Well of Ascension. This probably means that the Central Dominance, and perhaps the city of Luthadel itself, is actually situated at the North Pole of Scadrial. All other dominances (including the so-called North, East, and West Dominances, are actually situated to the south of the Central Dominance. Rashek also created the ashmounts, which began spewing ash and smoke into the atmosphere, causing ash to fall from the sky for a thousand years and making the sun appear blood-red through the hazy sky.