P5X-777, also designated PX5-777, was a planet in the Milky Way galaxy, which held a Stargate and served as the doorway into the paradise on the Utopian moon. The atmosphere is similar to that of the moon. An ancient Furling structure stands on the edge of a massive precipice, housing a transport portal that, when armed with the key, transports one to the Utopian moon. (SG1: "Paradise Lost")