So why had we received no signal? Could Dave possibly be right? No extraterrestrial civilizations anywhere? All those billions of worlds going to waste, lifeless, barren? Intelligent beings growing up only in this obscure corner of an incomprehensibly vast universe? No matter how valiantly she tried, Ellie couldn’t make herself take such a possibility seriously. It dovetailed perfectly with human fears and pretentions, with unproved doctrines about life-after-death, with such pseudosciences as astrology. It was the modern incarnation of the geocentric solipsism, the conceit that had captured our ancestors, the notion that we were the center of the universe. Drumlin’s argument was suspect on these grounds alone. We wanted to believe it too badly.
Wait a minute, she thought. We haven’t even examined the northern skies once with the Argus system. In another seven or eight years, if we’ve still heard nothing, that’ll be the time to start worrying. This is the first moment in human history when it’s possible to search for the inhabitants of other worlds. If we fail, we’ve calibrated something of the rarity and preciousness of life on our planet–a fact, if it is one, very much worth knowing. And if we succeed, we’ll have changed the history of our species, broken the shackles of provincialism. With the stakes this high, you have to be willing to take some small professional risks, she told herself. She pulled off the side of the road and did a shallow racing turn, changed gears twice, and accelerated back toward the Argus facility. The rabbits, still lining the roadside, but now pinked by dawn, craned their necks to follow her departure.
CHAPTER 4
Prime Numbers
Are there no Moravians in the Moon, that not a missionary has yet visited this poor pagan planet of ours to civilize civilization and Christianize Christendom?
-HERMAN MELVILLE
White Jacket (1850)
Silence alone is great; all else is weakness.
-ALFRED DEVIGNY
La Mort du Loup (1864)
The cold black vacuum had been left behind. The pulses were now approaching an ordinary yellow dwarf star and had already begun spilling over the retinue of worlds in this obscure system. They had fluttered by planets of hydrogen gas, penetrated into moons of ice, breached the organic clouds of a frigid world on which the precursors of life were stirring, and swept across a planet a billion years past its prime. Now the pulses were washing against a warm world, blue and whit, spinning against the backdrop of the stars.
There was life on this world, extravagant in its numbers and variety. There were jumping spiders at the chilly tops of the highest mountains and sulfur-eating worms in hot vents gushing up through ridges on the ocean floors. There were beings that could live only in concentrated sulfuric acid, and beings that were destroyed by concentrated sulfuric acid; organisms that were poisoned by oxygen, and organisms that could survive only in oxygen, that actually breathed the stuff.
A particular lifeform, with a modicum of intelligence, had recently spread across the planet. They had outposts on the ocean floors and in low-altitude orbit. They had swarmed to every nook and cranny of their small world. The boundary that marked the transition of night into day was sweeping westward, and following its motion millions of these beings ritually performed their morning ablutions. They donned great-coats and dhotis; drank brews of coffee, tea, or dandelion; drove bicycles, automobiles, or oxen; and briefly contemplated school assignments, prospects for spring planting, and the fate of the world.
The first pulses in the train of radio waves insinuated themselves through the atmosphere and clouds, struck the landscape and were partially reflected back to space. As the Earth turned beneath them, successive pulses arrived, engulfing not just this one planet but the entire system. Very little of the energy was intercepted by any of the worlds. Most of it passed effortlessly onward–as the yellow star and its attendant worlds plunged, in an altogether different direction, into the inky dark.
Wearing a Dacron jacket displaying the word “Marauders” above a stylized felt volleyball, the duty officer, beginning the night shift, approached the control building. A klatch of radio astronomers was just leaving for dinner.
“How long have you guys been looking for little green men? It’s more than five years, isn’t it now, Willie?”
They chided him good-naturedly, but he could detect an edge to their banter.
“Give us a break, Willie,” another of them said. “The quasar luminosity program is going great guns. But it’s gonna take forever if we only have two percent of the telescope time.”
“Sure, Jack, sure.”
“Willie, we’re looking back toward the origin of the universe. There’s a big stake in our program, too–and we know there’s a universe out there; you don’t know there’s a single little green man.”
“Take it up with Dr. Arroway. I’m sure she’ll be glad to hear your opinion, “he replied a little sourly.
The duty officer entered the control area. He made a quick survey of dozens of television screens monitoring the progress of the radio search. They had just finished examining the constellation Hercules. They had peered into the heart of a great swarm of galaxies far beyond the Milky Way, the Hercules Cluster–a hundred million light-years away; they had tuned in on M-13, a swarm of 300,000 stars, give or take a few, gravitationally bound together, moving in orbit around the Milky Way Galaxy 26,000 light-years away; they had examined Ras Algethi, a double system, and Zeta and Lambda Herculis–some stars different from the Sun, some similar to it, all nearby. Most of the stars you can see with the naked eye are less that a few hundred light-years away. They had carefully monitored hundreds of little sectors of the sky within the constellation Hercules at a billion separate frequencies, and they had heard nothing. In previous years they had searched the constellations immediately west of Hercules–Serpens, Corona Borealis, Boötes, Canes Venatici… and there also they had heard nothing.
A few of the telescopes, the duty officer could see, were devoted to picking up some missed data in Hercules. The remainder were aiming, boresighted, at an adjacent patch of sky, the next constellation east of Hercules. To people in the eastern Mediterranean a few thousand years ago, it had resembled a stringed musical instrument and was associated with the Greek culture hero Orpheus. It was a constellation named Lyra, the Lyre.
The computers turned the telescopes to follow the stars in Lyra from starrise to starset, accumulated the radio photons, monitored the health of the telescopes, and processed the data in a format convenient for their human operators. Even one duty officer candies, a coffee machine, a sentence in elvish runes out of Tolkien by the Artificial Intelligence Laboratory at Stanford, and a bumper sticker reading BLACK HOLES ARE OUT OF SIGHT, Willie approached the command console. He nodded pleasantly to the afternoon duty officer, now collecting his notes and preparing to leave for dinner. Because the day’s data were conveniently summarized in amber on the master display, there was no need for Willie to inquire about the progress of the preceding hours.
“As you can see, nothing much. There was a pointing glitch–at least that’s what it looked like–in forty-nine,” he said, waving vaguely toward the window. “The quasar bunch freed up the one-tens and one- twenties about an hour ago. They seem to be getting very good data.”
“Yeah, I heard. They don’t understand…”
His voice trailed off as an alarm light flashed decorously on the console in front of them. On a display marked “Intensity vs. Frequency” a sharp vertical spike was rising.
“Hey, look, it’s a monochromatic signal.”
Another display, labeled “Intensity vs. Time,” showed a set of pulses moving left to right and then off the screen.
“Those are numbers,” Willie said faintly. “Somebody’s broadcasting numbers.”
“It’s probably some Air Force interference. I saw an AWACS, probably from Kirtland, about sixteen hundred hours. Maybe they’re spoofing us for fun.”
There had been solemn agreements to safeguard at least some radio frequencies for astronomy. But precisely because these frequencies represented a clear channel, the military found them occasionally irresistible. If global war ever came, perhaps the radio astronomers would be the first to know, their windows to the cosmos overflowing with orders to battle-management and damage-assessment satellites in geosynchronous orbit, and with the transmission of coded launch commands to distant strategic outposts. Even with no military traffic, in listening to a billion frequencies at once the astronomers had to expect some disruption. Lightning, automobile ignitions, direct broadcast satellites were all sources of radio interference. But the computers had their number, knew their characteristics and systematically ignored them. To signals that were more ambiguous the computer would listen with greater care and make sure they matched no inventory of data it was programmed to understand. Every now and then an electronic intelligence aircraft on a training mission–sometimes with a radar dish coyly disguised as a flying saucer camped on its haunches–would fly by, and Argus would suddenly detect unmistakable signatures of intelligent life. But it would always turn out to be life of a peculiar and melancholy sort, intelligent to a degree, extraterrestrial just barely. A few moths before, an F-29E with state-of-the-art electronic countermeasures passed overhead at 80,000 feet and sounded the alarms on all 131 telescopes. To the unmilitary eyes of the astronomers, the radio signature had been complex enough to be a plausible first message from an extraterrestrial civilization. But they found the westernmost radio telescope had received the signal a full minute before the easternmost, and it soon become clear that it was an object streaking through the thin envelop of air surrounding the Earth rather than a broadcast from some unimaginably different civilization in the depths of space. Almost certainly this one was the same thing.