Fifteen Billion Years

Anderson, Poul, "Iron" IN Niven, Larry, Ed., The Man-Kzin Wars (London, 1989), pp.27-177.

(This time, I really will try to regard 160 as a good round number of posts for a month and hold off on any more posts until 1st April.)

"Iron" is the kind of speculative fiction that I have come to expect from Poul Anderson - speculation totally transcending the Man-Kzin Wars setting of this particular story.

A red dwarf star and its five planets numbered by their human discoverers from Prima to Quinta have moved between and through gaseous nebulae for fifteen billion years. That has been long enough for the gravitational fields of the planets and their moons to attract atoms and molecules from the nebulae and even from intergalactic space. This matter affects the surfaces of those planets or moons that have no atmosphere to counteract it. Thus, a carbon compound from space yellows the airless surfaces of the Secundan and Tertian moons.

That carbon compound is too cold to interact with complex organic compounds which therefore are a minor part of the downdrift. Because the sun emits negligible ultraviolet and solar wind, carbon-based molecules reach the airless Priman surface intact and, because Prima is only 0.4 AU from the sun, its surface is warm enough for the organics to interact. Sand, dust and meteor powder provide colloidal surfaces where the organics cluster and concentrate until complicated exchanges occur, seizing free carbon, hydrogen and oxygen atoms from the downdrift and possibly also adapting to extract matter from surface rocks. Growing patches meet and interact to form a single multiplex molecule or polymer covering the planet with differently colored areas displaying diverse local interactions. Other planetary systems are not old enough and have not passed through enough nebulae for these processes to have occurred in them.

On the atmosphere-bearing Tertia, organics from space evolved into intelligent beings who, lacking metals, became extinct in their stone age when their planet chilled, plants died and rocks bound the atmospheric oxygen. The planetary polymer is a more ingenious extrapolation than the extinct intelligences and the dramatic history of this wandering planetary system makes the Man-Kzin Wars seem very parochial.