because of the floating point limit, seriously, EVERY single game that is "infinite" (procedually-generated or infinite repeating hell) has this limit, why? because these sandbox games need to be seemingly "infinite" so they use the floating point system! a counting system which focuses on more numbers than more precision, and if you go out far enough the precision drops down to 1 to -1, 10 to -10 and then eventually its actually impossible to go further out at some point