Planets in science fiction and it is extremely hostile to life. Various planets of the Solar System were used as settings for science fiction stories in the first half of the 20th century; but dissatisfaction with the limits imposed by science led many writers early on to forsake the Solar System for fictional planets around distant stars. As increasing knowledge of the Solar System made the prospects of life in the vicinity of Earth marginal at best, the extrasolar planet has become almost the only venue for contemporary science fiction. In many works of science fiction, planets are only described casually, as points of
One of Our Planets Is Missing depart from this galaxy. "One of Our Planets Is Missing" is regarded by some entertainment critics to be "one of the best [shows] that animated [Trek] spin-off has to offer" and "a highly satisfying episode that nicely encapsulates the "Star Trek" philosophy. The show's "animation competently conveys the size and scope of the marauding cloud" which threatens the Federation world of Mantilles. Spock's "mind-meld with the cloud is both logical and satisfying, and Kirk and Spock's wrestling with the need to protect [all] life-forms is intelligent and provocative." Kirk even discusses the rationalisation for his decision "not to kill today"