Dimension space (次元空間 Jigen kūkan), sometimes translated as "sea of dimensions", is the featureless space that separates individual "dimension worlds" like Earth and Mid-Childa from each other. Although it remains unknown to contemporary science on Earth, the magic-oriented civilizations like Belka and Mid-Childa have long learned to travel through the dimension space to other worlds/dimensions. Such travel usually takes place aboard trans-dimensional spaceships (次元空間航行艦船 jigen kūkan kōkō kansen) like Arthra or Claudia, but it is also possible for sufficiently powerful mages to teleport directly to another world (see Dimensional Transfer). The technical details of dimensional travel have never been fully explored in the series.