"Frost and Fire" is a short story by Ray Bradbury and the fourteenth in his collection R is for Rocket. It was first published in Planet Stories (Fall, 1946) as "The Creatures That Time Forgot". The story is about short-lived humans on a planet similar to Mercury.[1]
The conditions on this world allude to Mercury, where the days are extremely hot, the nights extremely cold, and humans live for only eight days.