Hidden Hemispheres of Hyperspace

Hyperspace is defined as four or more dimensions folded upon itself, creating a multi-dimensional universal plane of existence. 

On one occasion, four Krptonian prisoners of the Phantom Zone discovered the means to reach a planet with unusual properties in an adjacent dimension they also labeled an "alternate universe"*. From this world, they launched deadly robotic Anachroids to wreak havok in space and time, until the Superman and Flash of Earth-One tracked them to their source and defeated these creatures and their masters. This trans-dimensional world may have been the same as Rokyn, where the Kandorians resided once Superman and Supergirl enlarged them.

This world had a counterpart in an "alternate universe"* of Earth-Two, a psuedo-Pluto which the Spectre had been exiled to, wherein the inhabitants spoke a language derived from that of the Andromedan Galaxy, the same galaxy where Krypton once resided! Could these have been long lost Kryptonian refugees? The domed city on this Pluto mirrored the once bottled city of Kandor. After quelling a civil war, Spectre later returned to this world, exiling Nazi agents there, no doubt out of revenge for their treatment of he and his Justice Society allies.

In face, six of his Justice Society colleagues had been simultaneously captured and also exiled into hyperspace via experimental rocketships by enemy Nazi agents. Hawkman was sent to a Saturn-like world named Arkania, a militant people like those of the extra-dimensional world Llorth, whom the Earth-One Hawkman once encountered. Later, the younger Hawkman traveled on twice through another dimensional warp to the world of Illoral, a mirror image of the Wingworld that Wonder Woman of the Justice Society visited more than once. Queen Desira and her daughter Princess Eve of Wingworld had counterparts in Dwyanna Ral of Llorth and Queen Maya of Floria.

The Atom of Earth-One and Doctor Mid-Nite of Earth-Two likewise visited other-dimensional worlds in Floria and Faux-Neptune (the Atom of Earth-Two visited a hyperspacial version of Mars like that of Mars II settled by the Martian Manhunter and his people in Earth-One's universe). 

Fellow Justice Society members Starman and Sandman visited worlds resembling Jupiter and Uranus with strange substance sentients as had the Metal Men of Earth-One , such as the alien Robot-spider Queen and minions of Metalus 5. Jimmy Olsen of Earth-One and Johnny Thunder of Earth-Two likewise ventured to alien dimensions on the same occasions as their peers Superman and Spectre above.

* The term "alternate universe" used for worlds visited by the individual Justice Leaguers and Justice Socialites as mentioned is different from that of planets in a "parallel universe". The alternate universe simply means an adjacent dimension attached to either the Earth-One or Earth-Two universe, respectively.