Alpha Centauri's Universe: Monthly Publication

"discovery" of an extensive pattern of Martian canals (canals that later observations of higher quality failed to find). In practice, "terraforming" does not imply the creation of an Earth look-alike; it describes, rather, the changing of another world to the point where organisms of our own planet, including humans, can live and thrive there.         When we examine Venus with this idea in mind, we see huge problems. Yes, Venus is almost the same size and has close to the same surface gravity as Earth. But Venus is blazing hot, with a surface temperature of more than 450*C--easily enough to melt lead. The Sun delivers twice as much radiation to the planet, and it proves easier to warm a world that is too cold than to cool a too-hot one.         Also, the air pressure at the surface of Venus is 90 Earth atmospheres.

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