A stargate is a fictional device that allows one to travel through a wormhole to distant locations. By the distant locations, it is to another planet and even another galaxy. There are 9 chevrons. These chevrons act as a 'dialling address' a navigation system to the location.
A stargate is made up of a fictional element called naquadah. These devices are made and spread all over the universe by a race called the Ancients. A typical Stargate measures 6.7 m (22 ft) in diameter, weighs 29,000 kg (64,000 lb).