The Sunborn by Gregory Benford Read Free Book Online

pattern we saw in Gusev.”
    Uchida, a sharp-eyed geologist, asked, “The magnetic field strength?”
    Viktor pointed to colored lines that peaked several times over the last several months. “Local magnetic fields go up, so does vapor pressure in the upper Marsmat chamber—only hours later. Same delay when fields fall.”
    Uchida called up a figure on an inset window. “Here’s the cause, I bet. We’ve got lotsa satellite data on this. Here’s a figure from a paper on the anomalies in the south. In the north the solar wind flows smoothly around, as it does on Venus. But the incoming solar wind veers around these field peaks—”
    “Look like magnetic mountains,” Viktor said, running his eyes down the sheets of data, histograms, and plots beneath the cartoon figure, checking, checking. The usual scientific acronyms could not obscure the flow of incoming solar winds—like the big one currently blowing—around pronounced mountainlike peaks in magnetic field.
    “Question is, what causes them? The geologists say it’s magma sheets, cooled off into magnetized rock.”
    Viktor looked at Uchida skeptically. “You are geologist.”
    “Yeah, but the agreement between this data and what we know about the magma from seismology, well…” Uchida shrugged.

    “Not good,” Viktor said.
    “The trouble is, it varies with time.” Uchida produced curves showing the rise and fall of the “magnetic mountains”—not everywhere, but in certain spots around Mars. Long silence.
    “And here’s the local vapor pressure at those places.”
    “Um.” Viktor studied the curves. More silence.
    “Julia, what do you think?” Viktor said.
    Distracted by the view, she studied the curves. Physics had never been her strong point, and she had no idea why the local magnetic fields should vary. But they did, the red line peaking every few weeks, the blue line of vapor pressure following. “Correlations don’t have to mean cause,” she said.
    Uchida asked, “Which means…?”
    “Maybe there’s magma underlying this whole area, moving now and then. When it flows in, the magnetic field rises. It melts deep layers of ice, which percolates up into the mat chambers.”
    Uchida pursed his lips. “But there are waves, too. Magnetic waves.” He showed them different curves, these labeled with dates. Long sinusoids pulsed for hours, then faded. They combined at times, shaping into complex waveforms.
    “Hey, I’m not a geophysicist,” Julia said, throwing up her hands.
    “It doesn’t make sense to me, either,” Uchida said. “Using the magma model”—he nodded to Julia with, it seemed to her, totally unnecessary diffidence—“these waves would come from fluid movements of the magma in constricted passages.”
    He and Viktor got into an extended technical discussion.
    Julia turned to the big port view bubble and relaxed, preparing herself for the coming descent, and watched a new vista unfold. Crystalline strata sparkled with diamondlike facets in the hard sunlight. Sullen lava flows were as dull as asphalt in spots, and in others where the dust had worn them, shiny as black glass. And everywhere, reds and pinks in endless profusion, myriad shades depending on composition, time of day, and angle of sunlight. The crater cliffs began as brooding maroon ramparts at dawn, then lightened to crimson at noon and slid into blood red in the afternoon’s slanting rays.
    Ayers Rock cm Mars. I went so far away and found myself still at home.
    In the red twilights of the long years here she had recalled her girlhood in Australia. Not the rural summers with relatives north of Adelaide, with their droughts, brush fires, and smelly sheep, no. Nor the flies and hard work. Instead, the wide skies and wildlife returned to her in memory. The eucalyptus trees were beautiful and endlessly varied, with names like rose-of-the-West, yellow jacket, jarrah, Red River gum, half mahogany, grey ironbark, and especially the ghost gum, which she soon learned