Optimistic solar systems

In conjunction with the last post on space opera and sword & planet, one of the hallmarks of these genres is that they posit an extremely optimistic view of how likely each of these planets are to support Earth-like life. Up until the 1960s or so, when unmanned probes first started giving us close-up views of Mercury, Venus, Mars and other planets, this wasn't necessarily out of synch with established science, but much of the material, especially the sword & planet retro genre, just ignored science altogether and had the fundamentally improbable ideas that Callisto, Ganymede or others were capable of supporting Earth-like life and human habitation as is.

Leigh Brackett's solar system which lasted in stories from the 40s through the 60s was a great example of what science fiction authors believed about the planets, and for its time, was reasonably accurate in its science, despite not really being categorized as hard science fiction. It bears numerous similarities with the science fiction settings of other writers of the time, including Moore's Northwest Smith stories, Hamilton's Captain Future setting, and even Kline and Burroughs's earlier adventure stories of the planetary romance genre. Mercury is believed to be tidally locked with the Sun, which creates a habitable belt along the terminator, and sun-baked and frozen areas outside of this narrow range. Under Venus's cloud cover, the surface is presumed to be a runaway tropical biota. Mars is a dessicated desert, fed by canals and populated with the decadent and degenerate remains of ancient civilizations.

I really like this optimistic approach to the solar system. The fact that Venus and Mars are completely incapable of harboring any kind of life as we know it is certainly very disappointing.

Another interesting side effect of this is the prevalence of one environment planets in the genre. As an example, let's look at Star Wars: you've got a desert planet (Tatooine), a forest planet (the moon of Endor), a swamp planet (Dagobah), and ice planet (Hoth), and more. I'm not quite sure what the need is to have the entire planet be engulfed in a single environment. Would Star Wars have been a significantly different story if Tatooine had been set in the Sahara, Hoth in Antarctica, Endor on the west coast of North America, etc. and the Death Star been a gigantic flying fortress capable of dealing out massive damage via superlasers? I don't really think so.