Tales of Old Earth Read Free Page A

up.”
    She topped the ridge. The plains ahead were smooth and undulating. They reminded her of the Moon, in the transitional region between Mare Serenitatis and the foothills of the Caucasus Mountains, where she had undergone her surface training. Only without the impact craters. No impact craters on Io. Least cratered solid body in the Solar System. All that volcanic activity deposited a new surface one meter thick every millenium or so. The whole damned moon was being constantly repaved.
    Her mind was rambling. She checked her gauges, and muttered, “Let’s get this show on the road.”
    There was no reply.
    Dawn would come—when? Let’s work this out. Io’s “year,” the time it took to revolve about Jupiter, was roughly forty-two hours fifteen minutes. She’d been walking seven hours. During which Io would’ve moved roughly sixty degrees through its orbit. So it would be dawn soon. That would make Daedalus’s plume less obvious, but with her helmet graphics that wouldn’t be a worry. Martha swiveled her neck, making sure that Daedalus and Jupiter were where they ought to be, and kept on walking.
    Trudge, trudge, trudge. Try not to throw the map up on the visor every five minutes. Hold off as long as you can, just one more hour, okay, that’s good, and another two miles. Not too shabby.
    The sun was getting high. It would be noon in another hour and a half. Which meant—well, it really didn’t mean much of anything.
    Rock up ahead. Probably a silicate. It was a solitary six meters high brought here by who knew what forces and waiting who knew how many thousands of years just for her to come along and need a place to rest. She found a flat spot where she could lean against it and, breathing heavily, sat down to rest. And think. And check the airpack. Four hours until she had to change it again. Bringing her down to two air-packs. She had slightly under twenty-four hours now. Thirty-five miles to go. That was less than two miles an hour. A snap. Might run a little tight on oxygen there toward the end, though. She’d have to take care she didn’t fall asleep.
    Oh, how her body ached.
    It ached almost as much as it had in the ‘48 Olympics, when she’d taken the bronze in the women’s marathon. Or that time in the internationals in Kenya she’d come up from behind to tie for second. Story of her life. Always in third place, fighting for second. Always flight crew and sometimes, maybe, landing crew, but never the commander. Never class president. Never king of the hill. Just once—once!—she wanted to be Neil Armstrong.
    Click .
    â€œThe marble index of a mind forever. Voyaging through strange seas of thought, alone. Wordsworth.”
    â€œWhat?”
    â€œJupiter’s magnetosphere is the largest thing in the solar system. If the human eye could see it, it would appear two and a half times wider in the sky than the sun does.”
    â€œI knew that,” she said, irrationally annoyed.
    â€œQuotation is. Easy. Speech is. Not.”
    â€œDon’t speak, then.”
    â€œTrying. To communicate!”
    She shrugged. “So go ahead—communicate.”
    Silence. Then, “What does. This. Sound like?”
    â€œWhat does what sound like?”
    â€œIo is a sulfur-rich, iron-cored moon in a circular orbit around Jupiter. What does this. Sound like? Tidal forces from Jupiter and Ganymede pull and squeeze Io sufficiently to melt Tartarus, its subsurface sulfur ocean. Tartarus vents its excess energy with sulfur and sulfur dioxide volcanoes. What does. This sound like? Io’s metallic core generates a magnetic field which punches a hole in Jupiter’s magnetosphere, and also creates a high-energy ion flux tube connecting its own poles with the north and south poles of Jupiter. What. Does this sound like? Io sweeps up and absorbs all the electrons in the million-volt range. Its volcanoes pump out sulfur