New Cybertron was a planet that was nearby Cybertron. The Decepticons created this planet and saw much similarity to Cybertron. Thus naming it New Cybertron. New Cybertron appears to be smaller than Cybertron and Earth but about the same size as Earth's Moon, Luna.
At Megatron's orders, Shockwave had created a planet cloning machine which he used to clone Cybertron. This clone planet would later be New Cybertron. Shockwave created this planet so the Decepticons constructed a colossal space bridge that actually transported the entire planet into the Sol system, into Earth's orbit, where its gravity wreaked havoc with the planet's natural balance, unleashing an unending torrent of energy created by natural disasters. The energy acquired re-energized Cybertron enough to put New Cybertron out of the danger zone, but the planet was soon knocked out of orbit by a massive energon explosion, and set drifting off through the solar system.
It was at this time that New Cybertron came under attack from the prototype of the world eater, Unicron, who consumed the two moons and assaulted New Cybertron itself, only to be destroyed by the power of the Autobot Matrix of Leadership. His deactivated, decapitated head fell into orbit around New Cybertron, a grisly new satellite to replace those he had destroyed. New Cybertron was equipped with a system of energon towers that could surround the planet with a protective field, which has since been disabled due to Decepticon attack.
The Decepticons occupied New Cybertron and used the energon grid to turn New Cybertron into a mobile juggernaut, placing it on a collision course with Plains Planet until the Autobots were able to destroy enough of the towers to shut them all down. New Cybertron remained in Alpha Q's universe.