I've recently discovered a podcast called The Geek's Guide to the Galaxy, which I can't recommend highly enough. With reasonably lengthy interviews with the likes of William Gibson, George R. R. Martin, Richard Dawkins, Simon Pegg, Neal Stephenson, and Chuck Palahniuk, and always-thoughtful-and-entertaining discussions on topics as varied as "Africa in Fantasy & Science Fiction", "Satan", and "Dungeons & Dragons", it's pretty much guaranteed to appeal to readers of this blog.
I'm slowly working my way through their back catalogue, and tonight ended up listening to to this episode. Once you get past the Catherynne M. Valante bit (which I confess did not particularly interest me; if there is one criticism of the show I would make, it's that there are too many interviews with Young Adult Urban Fantasy We're All Faeries in the City-type writers, who are not to my taste) the discussion moves on to the topic of "pulp era Venus and Mars". One of the presenters makes the interesting point that, to pulp writers, it was as if the further one got from the sun, the more ancient, advanced, and decadent things became. Venus, close to the sun, was a world of dinosaurs, oceans, and primordial wonder. Mars, far from the sun, was a place of antique, decaying civilizations almost given over to barbarity and scattered with ruins and remnants of forgotten societies.
This got me thinking: what if you were to take this further and expand it to include all the 9 planets for a solar system-spanning Sword & Planet setting? (If you feel yourself about to butt in along the lines that Pluto is no longer a planet - go to the nearest mirror and take a long hard look at yourself and ask yourself whether you have made all the correct life choices.)
If the further you get from the sun, the older things get, Mercury would be the most primordial place of all, right? I picture it as a world of magic, thaumaturgy, elementals, and spiritual entities who are barely distinguishable from the stuff from which the universe is created - the phlogiston, if you will.
On Pluto there would naturally be nothing left alive, but deep, deep below the ice which covered it there would be buried the ruins of impossibly old cities with forgotten technologies.
Jupiter, Saturn, Uranus and Neptune are where it gets harder. But you get the idea. What do you want, something coherent on a Sunday night at 8pm?