Solar Planets In The Pulps And Later In Heinlein, Asimov, Blish, Anderson And Stirling

Follow the link from "Northwest Smith " in Planetary Adventurers.

Ninety years ago, pulp sf writers treated the Solar System like a galaxy of inhabited planets with breathable atmospheres and even jungles on moons of Jupiter. Such an approach even affected Robert Heinlein's Future History although that series is primarily about the future development of human society, not about human-alien interactions. Isaac Asimov admitted in The Early Asimov that he wrote in this tradition even when he knew better.

We can see later writers emerging from the tradition. In James Blish's Cities In Flight and Mission To The Heart Stars, Martians had existed but are now extinct. Poul Anderson has half a dozen versions of Martians. There are Martians in his Psychotechnic History and in the original version of his "Margin of Profit" although, when that story was revised to fit into his Technic History, these "Martians" had become extra-Solars who had colonized Mars. Anderson also has Venerians in "Sister Planet," Jovians in Three Worlds To Conquer and Mercurians in "Life Cycle." 

When SM Stirling wrote a series in which Mars and Venus turned out to be more or less how earlier sf writers had imagined them, he also worked towards an explanation. A scientist working on Venus says:

"'Sam thinks...and I think...that two hundred million years ago, in the earliest Jurassic...this planet was different. Radically different from what we have now; as far as we can tell, it didn't have life at all. And we don't have any idea what changed it.'"

-SM Stirling, The Sky People (New York, October 2007), CHAPTER TWO, pp. 40-41.

But they will find out.