Complex sentence: The Bubbleworld concept was popularized by science fiction author Larry Niven in his fictional Known Space stories, describing these worlds as the primary habitats of the Belters, a civilization who had colonized the Asteroid Belt.
Split into simpler sentences: The Bubbleworld concept was popularized by science fiction author Larry Niven. Niven used the idea in his fictional Known Space stories, describing these worlds as the primary habitats of the Belters, a civilization who had colonized the Asteroid Belt.