The story is “noteworthy not only as an impressive piece of planet-building, but as the first SF novel built on actual observational data involving another possible solar system”, making it an early and often-praised example of macrocosmic
worldbuilding hard science fiction. Although Clement has stated that his original calculations concerning the polar gravity of Mesklin were inaccurate — he later estimated the polar gravity should have been approximately 250 g instead of 700 — the exploration of what existence might be like in such extreme conditions is detailed, convincing, and persuasive. The novel is frequently invoked in discussions of the
sense of wonder, the sensation of dawning comprehension and understanding of a larger context for a given experience, that many readers of science fiction point to as the reason why they pursue the genre. The personalities of Clement's alien characters have been criticized as being "too human" or not "alien enough", as failing to be, in the words of
John W. Campbell "something that thinks
as well as a man, but not
like a man". ==Analysis==