09 January 2007

Planetocopia: Alternate worlds

Chris Wayan has a mission - to create alternate, realistic worlds and then describe them in amazing detail. Some of the worlds start with Earth, and then change one element like the tilt of the Earth's axis.

Others are possible futures for Venus, Earth, and Mars.

And then there's Lyr, a thought experiment in designing a world very much unlike Earth and yet capable of sustaining life.



Lyr's a world-model challenging exobiologists like Peter Ward Douglas ("Rare Earth"), who say complex life will only evolve on worlds almost exactly like Earth. Lyr is emphatically not Earth! Seven times as massive, in an eccentric orbit too far out from its dim little sun, with the wrong density, wrong tilt, wrong satellites, wrong geology, wrong water content... can you get wronger? Douglas says big wet worlds like Lyr will be (at best) world-seas, poor in minerals, with sparse unicellular life at most, and if it's multicellular than not intelligent, and if intelligent than not technological.

Tell that to the Lyrans.


Our solar system's mass-gap between gasbags and rocks has given us an imagination-gap. Even science fiction, usually quick to explore possibilities, has very few middleweight worlds: Silverberg's "Majipoor" series plus short stories like Tiptree's "With Delicate Mad Hands" or pulp tales like "We Guard the Black Planet" or "Heavy Planet". Scientifically, they range from sloppy and unconvincing to downright silly. Only Poul Anderson's "The Man Who Counts" (discussed in Lyr's Evolution) details a fairly plausible middleweight world--and even it has problems.

In short: such worlds are a blind spot in the human imagination--ignored as potential biospheres. So... let's put this common planetary type center stage.

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