The formation of planetesimals is the biggest unsolved problem in the nebular disk model. He also outlined his cosmology, which included the first presentation of his nebular hypothesis. In particular, creationists dispute the widely accepted nebular hypothesis for star formation. There is evidence that Emanuel Swedenborg first proposed parts of the nebular theory in 1734. In the framework of the solar nebular model two theories for their formation exist. According to the nebular hypothesis, the outer two planets may be in the "wrong place". These included "Rex Nebular" in 1992 and "Return of the Phantom" and "Dragonsphere" in 1993. "Computer Gaming World" opined that "Rex Nebular" had "impressive" sound, graphics, and rotoscoped animation.