Superman was summoned by five fellow members of the Justice League to view an artifact that Aquaman's pet octopus had found deep in the sea. It was a recording from Jor-El, showing how he consulted the Computer Forecaster on Kal-El's future on any one of six different planets:
Planet Ganger: where Flash (Kal-El) became the Flash.
Jor-El discovered that Kal would not be happy on any of those worlds, and sent him to become Superman on Earth, where he would be appreciated and loved.