Spinneret by Timothy Zahn Page B

she ventured. “Are you worried about meteors hitting us?”
    â€œYes, but not the way you’re thinking.” He waved toward her window. “Teardrop Lake over by Ceres. If you look at it on satellite photos you can see that it’s a circular depression that’s been eroded by the rivers entering and leaving. The Dead Sea southeast of Olympus is the same thing plus what appear to be fault-line appendages. Even Splayfoot Bay shows a deep area in the center that’s basically circular. This planet has been literally pelted with rocks over maybe the last half million years—not surprising when you consider how close we are to the asteroid belt here. So where’s all the metal those meteorites brought down with them?”
    Watching her, he noted with approval the furrowing of her forehead. At least she recognized the paradox there; some he’d talked to hadn’t even made it that far. “Well … could the Rooshrike survey data be wrong?”
    â€œThat’s the most likely explanation,” Hafner nodded. “The problem is that we’ve done our own spot checks since then. Our equipment doesn’t have their half-kilometer range, but the chunk of rock that dug out Splayfoot Bay ought to have left some of itself scattered through the topsoil.”
    â€œThen maybe the asteroids that hit were just as metal-poor as Astra,” she suggested. “If the whole system formed from the same cloud of dust … no. Doesn’t work, does it?”
    â€œNot when we know the Rooshrike are mining metals on the first planet,” Hafner agreed. “Besides which, some of the smaller asteroids were analyzed by the original survey team and turned out to have a reasonable metal content. No, whatever happened here happened only to Astra.”
    They rode in silence for the next few minutes. Ahead, the hazy cone of Mt. Olympus gradually became sharper, the low angle of sunlight showing first the gross and finally the fine structure of its surface. Hafner watched with undivided interest, eyes probing for clues as to the type of lava that had formed it. The steepness of the cone suggested viscous lava flows, which on Earth would mean a predominance of andesitic rock. On the other hand, he could see little evidence of the surface characteristics that usually accompanied that type of lava. Still, if the volcano had been dormant for a long time, erosion would have altered many of the visual reference points. As with everything else in geology, there was ultimately no substitute for physically digging out the rocks and analyzing them.
    â€œWhat about some weird process that breaks the metal down?” Carmen spoke up abruptly. “A nuclear fission sort of thing. Maybe it’s some organism’s way of producing energy.”
    â€œChemical energy is a lot safer to work with,” Hafner grunted. An interesting idea … but the flaw was easy to find. “Besides, that would only get rid of elements in the bottom half of the periodic table. Sodium is far too light a metal to fizz, but Astra hasn’t got any of it, either.”
    â€œOh. Wait a minute.” She threw him a puzzled look. “No sodium either? But I thought Astra’s ocean was salty.”
    â€œNot really. There’s a fair assortment of stuff dissolved in it, but none of it strictly qualifies as salt. A salt, you see, is formed by replacing the hydrogen atom in an acid by a metal, as in hydrochloric acid to sodium chloride. Without metals, the acids remain as is or make bonds with oxygen or silicon.” He shook his head. “We’re sitting on a genuine treasure trove of strange chemistry here. Compounds that wouldn’t last five seconds on Earth are just lying around waiting to be examined. I think we’re up to eighteen brand-new carbon compounds alone since we’ve landed.”
    â€œAnything valuable?”
    â€œYou mean in terms of sending to Earth? So far, no. But