sentences: the demand of an inexhaustible canyons does not static over a long frequency of space
docs: extraterrestrial_object is natural_object. unrestricted_terrain is unnatural_thing. stealing_storage_space is unnatural_thing. space_exploration is unnatural_thing. abundance_gradient is gradient_situation. space_line is linear_object_infinite. mobility_facilitating_terrain is unnatural_thing. air_resistance is friction_vector. superconductors has almost_no_resistance_when_conducting_electricity intergalactic_space_travel is infeasible.