Martian soil perchlorate readings being caused by terrestrial sources, which at the time were thought could have migrated from the spacecraft either into samples or the instrumentation. However, each new lander has confirmed their presence in the soil locally and the "Mars Odyssey" orbiter confirmed they are spread globally across the entire surface of the planet. While our understanding of Martian soils is extremely rudimentary, their diversity may raise the question of how we might compare them with our Earth-based soils. Applying an Earth-based system is largely debatable but a simple option is to distinguish the (largely) biotic Earth from the abiotic
Planet Stories is the folk-tale, the hero-tale of our particular niche in history". Also arguing in support of "Planet Stories", science fiction critic John Clute has commented that "the content was far more sophisticated than the covers". Bradbury's work for "Planet Stories" included two of the stories that he later incorporated into "The Martian Chronicles", including "The Million Year Picnic"; only one other story in the series had appeared before this. He also collaborated on a story with Brackett, "Lorelei of the Red Mist", based on an idea of hers, which appeared in the Summer of 1946. His stories for "Planet" demonstrate