Across the Sea of Suns

by Gregory Benford

  Channel #20: “—so see this fits what the backscatter boys say, the faultin’ rips up the goddamn turf so much the iron gets reprocessed alla time an’ the air, it jess can’t hold onto its oxygen, the water jess runs off ever’ time it rains an’ the sea, it’s jess this solution a ferrous crap, ’at’s where th’ O2 is, man I tell you—”

  Channel #56: “That jocko over in P4 has got some crazy idea, lissen to him, thinks it’s all iron, but give a gear at this, in the big spot there, see that big volcano, that’s sulfur for sure, big spouts of it coming out reg’lar as Maybelle, sulfur volcanoes smack in the middle of the Eye, and if that doesn’t tie up a lot of oxy, with those winds, I mean, we measured gusting velocity from the action-frame zats and they’ll mix the whole damn atmosphere in two, maybe three years, so you’ve got sulfur oxide all down there, that’s what the Eye is, that’s not sand dunes, not silicon dioxide, it’s sulfur dioxide—”

  The picture sharpened as computers edited out random refractions from the clotted air below. Isis swam nearer.

  Yellow. A dry, ancient yellow. Smooth sands of it, shimmering, flecked with tan ridges of weathered rock. The Eye peered at Ra, which hung forever directly overhead. Out from the hard-baked center, the subsolar point, swept winds heavy with pungent acid dust. Dunes marched before the winds in ranks a hundred kilometers long. Slowly they swerved as the air currents circled, following a trade-wind pattern, returning to the blistered pupil of the Eye, surging in a timeless cycle.

  The Eye’s edge faded into russet, then into brown. A hint of moisture; scrub desert. Rumpled red hills built into a concentric ring of mountains: socket of the Eye. Snow dotted the peaks white. High valleys cupped cold air over the steel-blue sheen of lakes.

  The steady rub of the Eye winds had smoothed the land. The breeze stirred up pink dust, thick sheets that poured over the high mountain slopes and down, out-ward from the Eye, filling the valleys with a roiling haze. Only in the shifting spots where neither clods nor dust lay upon the land could the distant telescopes see the dry plains and carved valleys of Isis.

  The single, immense, concentric mountain range was intricate and fault cut. Muddy rivers ran down the broad slopes, away from the Eye, toward the planet-circling sea. Farther from the Eye, scrub desert yielded to matted vegetation. Brown grass. Something like trees. Shades of brown, of pinks and grays and pale orange.

  A fine dust hung in the lower air, fuzzing optical images, stealing definition. Only in the infrared was the seeing good enough to distinguish objects in the five-meter scale range. Large flora. Bands of vegetation crowding the snaking rivers.

  The IR peered down and picked out detail. Dark beds of plant life in the sea. Grasslands. And then, movement.

  “ReppleDex, this is Command. You guys got that system up yet, or do we kick ass out there?”

  We got good definition in the radio right now, Ted. Give it a—

  “I’m looking at it, Alex. What we want is the interferometry—”

  “They’re point sources, aren’t they?”

  “Nigel, this is Ted. Get off the comm lines.”

  “I’m a consultant, remember? Just eavesdropping, anyway.”

  “Okay, so long as you don’t get in the way of—Hey, RD, when can we have—”

  He’s right, Ted, we still can’t resolve the sources. They’re damned small. Any really big dish we could see at a range of one AU, so I’d think by now we shoulda picked up—

  “Okay, okay, that’s interesting. But—”

  —and the reason we’ve never been able to make sense out of the signals, we’ve got that figured now—

  “Oh? What?”

  There are these point sources, maybe a million of ’em, but they’re not transmitting together. I mean, they’re not in synch phase-locked. All the sources are trying to send the same stuff but they’re all a little behind or a little ahead of each other, so it gets muddied up.

  “Beats the hell out of me, why somebody’d pick that way for interstellar communication.”

  “Alex, what is the length over which the signals are correlated?”

  “Nigel, I asked you—”

  “Leave off a bit, eh? Alex?”

  Well, lemme run this here … Yeah, the spatial correlation length is about thirty klicks, maybe a little more.

  “How does it fit in with the topography?”

  Here, plug me in on that multichannel, Ted, and—Yeah, there it is.

  “Does it follow the valley profiles?”

  Uh, yeah. Sort of. Sources are strung out along the valleys. Not many in the mountains.

  “The valleys are where the best living is. The water. Over to you, Ted.”

  “Many thanks, Nigel. It is nice to get a word in now and then. Let me get this straight, Alex. If you scan the interferometer across the valley, you find the signal is coherent. All the point sources are sending together?”

  Correct.

  “But if you go to the next valley, the sources are sending something slightly ahead or behind of the first valley?”

  Yeah. That’s what’s so goddamn strange. The bit rate is still low, too. And the sources, they’re not steady.

  “How so?”

  Well, every few minutes one of ’em will drop out. A new one comes in every now and then, too, so the number is about constant.

  “Huh. Look, Alex, I called to ask about the outflyer dish. You were going to have it on line by 1400 hours, and that’s come and gone. We need that bigger base line to get the definition we need, and we damn well need it now.”

  “Give it a rest, Ted.”

  “Nigel, I thought you—”

  “Merely kibitzing, if you please. I’m sure Alex will have matters cleared up at his end if you cease ragging him about it. I wanted to take a moment to review all this, Ted. You’ve got the optical and IR profiles right in front of you, I’m sure.”

  “Yeah, you can come down here to Command and see them if you want.”

  “Already have. I’m sticking to this console, to use the self-programming capabilities. Anyway, Command is crowded.”

  “Okay, okay. If you’d wait for the input like the rest of the crew—”

  I was wondering if you’d considered the implications, Ted. No trace of cities. No urban areas. No big straight features, no fields or roads. And the EM transmissions are weak, except for that interstellar signal.”

  “Yeah. Damn funny. But maybe they’re living underground, using all the land for agriculture, and they use cables for info transfer. Hell, we do that back on Earth. We wasted power on atmospheric transmissions only in the start-up days of radio and TV.”

  “Even agriculture has a signature, this close. We could see croplands.”

  “Maybe so, maybe so.”

  “I’ve been cross-correlating Alex’s prelim fixes on the radio sources—the EM points, he calls ’em for electromagnetic—with the IR. Anyone in Command done that?”

  “Uh, I don’t—”

  “I’d like to check my work. There are signal-to-noise problems and I’ve been using the self-programming subsystems to unfold it—”

  “No, look, Nigel, we’ve been too busy to try all that yet. I’d suggest—”

  “Point is, some of the EM points and the IR points are the same.”

  “Which ones?”

  “There’s the rub. It’s the moving IR sources, looks like.”

  “The ones we got variable fixes on? I don’t under—”

  “What I’m saying, Ted, is that the radio transmitters give off heat as well. And most important, they’re moving.”

  “Well, I don’t—”

  Hey we’ve got this whole rig up, but you guys got to keep aligned with us or we’ll have shit to show for it when—

  “Alex, this is Ted, give us an overlay of your mapping. I want to match it—”

  With the IR?

  “Uh, yes.”

  Nigel was flimming me about that stuff. Wanted the early results. I just repped and verified the points he asked ab
out. They’re variable. Slow, but moving.

  “You’re sure?”

  Yeah. The IR points are pretty weak, almost fuzzed out by the thermal landscape background Jenkins told me they were probably small volcanic vents—

  “Not bloody likely.”

  “Since when did you become a geologist? Look, the dust and crap down there, nobody can be sure of that IR.”

  “Right. We have to go down and see.”

  “That’s a little premature, Nigel. We’re standing off at a safe distance. Going to surface mode now would violate our guidelines, and you know it.”

  “Dead right I know it. But that’s what we’ll have to do.”

  FOUR

  Ted arrived at Nigel and Nikka’s apartment a little late. He carried his usual prop, a clipboard jammed with notes. Nigel steered him first to the bar, then into the deep-cradled cushions of their new couch. Ted eased into it as if uncertain of its reliability; with its slanting legs and oblique joints, it looked rickety. Nigel had designed it for their apartment’s low gravity, using the wood he had in his personal mass allotment. He was the only person in Lancer with high-quality oak, and he had carefully carved this, polishing it with the oil of his hands.

  “Wish you’d come down to Command to talk,” Ted began.

  “It’s a jam down there.”

  “Yeah, pretty busy. No wonder you stay home, low gravity, plenty of rest—”

  Alex knocked; Nigel waved him in. Alex was a heavy, balding man, face dark with fatigue. He sat down on the couch like a man dumping a weight off his back. Muscles rippled in his shoulders as he flexed them, seeking an alert posture in the deep couch. Nigel had designed it to thwart such aims; finally Alex relaxed into it.

  “Whoosh!” Alex puffed. “I been worshipin’ those consoles like an acolyte.”

  “Drink?”

  “Just make me go to sleep.”

  “You’ve brought them, though?” Ted prompted.

  “Sure. I piped ’em down to your input here. They’re waitin on your screen.”

  Nigel said a soft “Thanks,” and thumbed on their flat. The screen filled with a grid. Small white dots peppered the green field. “These are your time-stepped maps, Alex?” Nigel prompted.

  “Yeah, weeks’ worth. I followed ’em one by one. Talk about your low bit rate—”

  Ted smiled and put his hands on his knees. “Well, it’s first-class work, Alex, all of it. First-class.”

  Nikka sat zazen beside Nigel, studying the men. “But the message?” she asked. “That’s what everyone’s waiting for, enough phase-coherent signal to tell—”

  “We’ve got it.” The words came out dry and tired.

  “You have?” Nigel said, surprised.

  “Yeah. It’s not all that hard, once you unnerstan’ that there are maybe one, two million, sources on at once. Each winks on and off, but what they’re doin’ is trying to boost the signal up by, well, ever’body chippin’ in.”

  Ted said carefully, “We haven’t released the information yet because it’s well, disturbing. But Alex has cracked it, that we’re sure of. Until—”

  Alex said wearily, emphatically, “It’s a 1956 Arthur Godfrey show.”

  “What?” Nikka said. “You mean … literally?”

  “Yeah. It’s a slow, slow playback of a radio comedy broadcast in 1956.”

  “Jesus Christ,” Nigel said with relish.

  Ted began: “We’ve been trying to place this in a context, to understand—”

  “So—we’ve come—!” Nigel erupted with laughter. The others sat, blinking, stunned. He roared on merrily, tears squeezing from under his eyelids. For a long moment the others were stiffly silent. Then they began to shift position awkwardly, looking at one another. Nikka slowly smiled. At last Nigel descended to a chuckle, gasped for breath, and seemed to notice them again.

  “The Bracewell hypothesis!”

  Ted nodded. “Some of us have ventured that explanation, but I feel it’s too early—”

  “Christ, it’s obvious! Those poor sods down there are intelligent, no mistake about that.”

  Nikka interjected, “But no more so than Dr. Bracewell.”

  “Right,” Nigel said, “because they’ve bit upon his same idea.” He spread his hands, palms up, open and obvious. “They picked up weak radio signals from us. Mulled them over. To get our attention, they figured the smartest strategy was, send back the same thing. Not some clever mathematical code or TV picture—hell, they can’t pick up TV, much less 3-D.”

  “Well …” Ted shifted among the pillows. “We’ve checked with our entertainment discs—an enormous file. The voice profile matches that of Arthur Godfrey, the most popular entertainer of the 1950s in the USA.”

  “Dead on,” Nigel said. “A crummy, old, fleabag radio show. Scandalously banal. Something we’d recognize.” He laughed again. “Ah, old Bracewell, would that thou could be with us now. …”

  Alex growled. “Depressing, you ask me. Come all this way, find out we’re listening to ourselves.”

  Ted patted Alex’s thick shoulder. “Look, this is a fantastic discovery. You’re just tired.”

  “Yeah. Maybe.” Alex sighed.

  “You’ve got something more, then, Alex?” Nigel said lightly.

  Alex brightened. “Uh, yeah, I had to track individual sources of the radio to get a phase fix. I figured, hell, might as well get ’em all. Just a rep-rate problem, following all those emitters on a time-sharing basis.”

  “Here.” Ted tapped his own wrist comm and the flat screen stirred to life. The white dots began to move, some winking on and off. “These EMs are also hefty infrared sources. From their body heat, I guess. They’re alive, and apparently each carries a transmitter.”

  “Perhaps a nomad culture?” Nikka said softly.

  “Well, we’ve thought about that. They don’t have fixed transmitters, that’s for sure, but as for why—”

  “Naw” Alex put in. “I got a few that don’t move.”

  “Oh?” Ted asked, puzzled. “Is your resolution good enough to be—”

  “Yeah, look, see that?” Alex lurched to his feet and walked to the flat. He pointed to a cluster of dots that did not join in the slow snowflake swirl. “These aren’t goin’ anywhere. I can tell for sure ’cause they’ve got little individual signatures in the radio spectrum, if you look close. Li’l shifts in the phase and amplitude, stuff like that.”

  Nikka studied the dots as they moved in jagged little jumps. “A few remain still. Perhaps they are old? They no longer take part in the nomadic cycle?”

  “Doesn’t look nomadic to me,” Nigel said. “They aren’t moving all together. Look how well spaced they are. They don’t cluster.”

  Ted nodded. “Correct. They move through the valley systems, Alex thinks. Sometimes they follow the dust clouds, sometimes not.”

  “Any optical fix yet?” Nigel asked.

  Ted shook his head. “Dust, clouds, damn dim sunlight in the first place …”

  “What is the next step, then? We cannot stand out here in the dark forever,” Nikka declared firmly.

  Ted said, “Well, our resolution is—”

  “About as good as it’s gonna get,” Alex said.

  Nikka said mildly, “Then perhaps it is time for the surface probes?”

  The vessels fell, crisp and clean. Winds scorched them; billowy parachutes eased their fall. The slumbering world below was mottled and cloud-shrouded. In some lacing valleys the dryness of the sulfur dust prevailed. There, brackish ponds greeted the first flyback probe.

  In the wetter valleys the dust rolled over damper air beneath. Mud fell from the sky. The sluggish rivers were clogged with it. Twisted yellow weeds sprouted on the banks and curious, small creatures scuttled for safety when the second probe popped and murmured and thrust forth a jerking, ratcheting scoop.

  Green greeted the third probe, where water had won a permanent victory. The roiling dust blew in nearby mountain passes, but did not eddy and fall here.
For this spherical, inquisitive probe the feast of life was more rich. And richer still was the land toward the seas.

  The flyback strategy was smash-and-grab. They were instructed to boost at the first sign of anything large. Thus the fifth probe took only one lingering view of the approaching EM creature which had been drawn by its whooshing crash. But the image was clear: a huge thing, leathery, unclothed. Three thin arms rode above the tangle of stiff legs. An awesome head.

  It carried nothing. No tools. No radio transmitter.

  It had no eyes.

  Instead, there was a chunky, rectangular slot in the huge head, a meter across. It turned toward the probe, just as the boosters fired to fling the black cylinder skyward. The probe radio registered a burst of noise, a crisp sputter. Then the landscape dwindled below and the thick pink clouds of Isis consumed the EM creature.

  But the spiky rattle in the radio spectrum had come from the creature itself. That much was sure.

  FIVE

  Preliminary exploration inched on. Nigel tried to hasten matters, but he had long ago learned the uselessness of trying to put body English on the universe.

  Instead, he worked in the fields and tanks, making the fat vegetables swell under ultraviolet phosphors. Rubbery plants stretched tall, driven not by nature’s cruel competition but by well-runed DNA, stepchild of laboratories. Amid these cathedral trees of 99 percent usable, man-centered life, he walked with a slow shuffle, hoarding his energy. The other men and women on the agri team did their work with a quick, efficient energy, but they flagged at the end of the shift, more from boredom than fatigue. Nigel did it slowly because he liked the musk and raw damp of the soil, the click of the hoe, the lofting high into the air of a bundle of rattling dry stalks.

  The aliens had given him that. The ability, the oddly tilted sensitivity, had been in him—was in everybody—and the blinding moments in direct contact with the Mare Marginis computer, in the splintered alien ship, had set it loose. In the first years afterward, the stink of enlightenment had followed him everywhere. Before, the dripping of water from a thick-lipped stonework urn had been a restful, pretty sight, nothing more. Then, after the Mare Marginis ship, the same dripping had become a wonderful thing, packed with meaning. Now, at last, it was a dripping into a thick-lipped urn again.