McCollum - GIBRALTAR STARS by Michael McCollum

species’ optical receptors. By determining the wavelengths to which an individual’s eyes were most sensitive, the spectrum of his home star could be extrapolated.
    Likewise, musculature and limb arrangement revealed the gravitational pull of the home world, as well as offered a clue as to biotic conditions. Fins and hydrodynamic sculpting pointed to an aquatic origin; while quadrupeds and centaurs tended to be ground dwellers. Most bipeds were descended from arboreals.
    Further, bipeds could be divided into Brachiators and Striders. Brachiators, like Dos-Val himself, were descended from animals whose physical size made it difficult for them to scamper atop vines. They found it more efficient to swing beneath the stalks.
    Striders were arboreal quadrupeds whose ancestors were forced out of the vines early in their evolution. They were vertically oriented animals forced to live in the horizontal world of the dangerous ground. The fugitives were obviously Striders.
    From the structure of their eyes, he assumed they evolved under a star that emitted yellow-white light, with either a tint of green in its spectrum or a canopy of chlorophyll-laden leaves overhead. Their naked skin spoke of a mean planetary temperature well above the melting point of water. Their well-regulated body temperature put an upper limit on the temperature of their world. The fact that they cooled themselves by evaporation spoke of a planet with a low average humidity, at least in the areas where their kind originally developed. This, in turn, suggested large, continent-sized land masses.
    In other words, they came from a planet not unlike Ssasfal. This was not exactly ancestor-astonishing news. Most intelligent beings came from worlds that were at least passable imitations of the Home World.
    It was not possible to tell from their eyes whether their yellow star was a giant or a dwarf. However, knowing its approximate spectrum narrowed the search parameters. There were fewer yellow stars in Civilization than orange, and substantially fewer yellow than red; but still far too many to launch a physical search on the little information he possessed.
    The fugitives’ biochemistry was nothing special. They shared the basic life code of all carbon-based forms and were close enough to Broan that the two species could consume the same food, with only minor supplements to maintain health.
    It was that very fact that gave him an angle from which to approach the problem.
    Carbon biochemistry replicates itself so consistently from world to world that the phenomenon had long been a matter of debate among biologists. One faction maintained that the building blocks of carbon-based life are unique, and therefore, must be found wherever “life” has appeared. Other biologists held that space-borne precursors of life were responsible for spreading the code throughout the galaxy.
    Even though the constituents of the bipeds’ life code were common to all living things, the arrangement of those building blocks was unique, as it is on every isolated world. Dos-Val was in possession of their chromosome map, which gave him the key to identifying their home planet.
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    The code of all living organisms was supposed to be filed in the central data banks of Ssasfal. Indeed, the collection of such data was something of a fetish among Those Who Rule. Thus, when the bipeds’ life code did not surface during a search of the databanks, its absence had caused alarm horns to sound at the highest levels of the Ruling Council.
    It was one thing for the sector data banks to be incomplete. Civilization was large and unwieldy. It could take as long as a generation for data to percolate from one side to the other. However, it was much less likely for the strangers’ life code not to be in the central databanks. The only logical explanation was that someone had deliberately expunged the data. Such an act was a violation so blatant as to suggest a nefarious intent.
    Still, difficult as it