The Worldmind is the primary source of knowledge, energy and power of the planet Xandar and the Nova Corps. The Xandarians have preserved the minds of their deceased brothers and sisters, linking them together in the Worldmind, creating a governing system unlike any across the Universe. The Worldmind served as a Multiple Mind Democracy using the knowledge of it´s deceased citizens to make decisions for Xandar and the Nova Corps.
When the people of Xandar were eradicated by Nebula, the Worldmind shut down and the Xandarian spheres were no longer habitable. The Nova Force was given to Garthan Saal and Richard Rider. Rider was chosen because he possessed the spirit of the Xandarians. While the full Nova Force drove Garthan Saal mad, Rider was able to use the power to restart the Worldmind and give Xandar it's rebirth.
After the destruction of Xandar and almost all of the Nova Corps during Annihilation, Worldmind was forced to upload itself into the last Nova Corps member, Richard Rider, as well as all of the Nova Force. This burden is typically impossible to bear seeing as such a feat usually drives the host insane, but Worldmind worked to protect Nova from these effects.
The Worldmind contains and controls the Nova Force, the cosmic energy that provides the Nova Corps and its members with extraordinary abilities. Those abilities consist of the ability of flight, super strength and a connection to the Worldmind itself. Those who are higher ranked in the Nova corps can tap into more powers such as the ability to open stargates, energy blasts and the release of a brief but devastating electromagnetic burst. Worldmind also provides logistical support for the Nova Corps.