* * *
The two-lane blacktop highway, Ellie noticed with a pleasant little tremor, was lined with rabbits. She had seen them before, especially when her drives had taken her as far as West Texas. They were on all fours by the shoulders of the road; but as each would be momentarily illuminated by the Thunderbird’s new quartz headlights, it would stand on its hind legs, its forelimbs hanging limply, transfixed. For miles there was an honor guard of desert coneys saluting her, so it seemed, as she roared through the night. They would look up, a thousand pink noses twitching, two thousand bright eyes shining in the dark, as this apparition hurled toward them.
Maybe it’s a kind of religious experience, she thought. They seemed to be mostly young rabbits. Maybe they had never seen automobile headlights. To think of it, it was pretty amazing, the two intense beams of light speeding along at 130 kilometers an hour. Despite the thousands of rabbits lining the road, there never seemed to be even one in the middle, near the lane marker, never a forlorn dead body, the ears stretched out along the pavement. Why were they aligned along the pavement at all? Maybe it had to do with the temperature of the asphalt, she thought. Or maybe they were only foraging in the scrub vegetation nearby and curious about the oncoming bright lights. But was it reasonable that none of them ever took a few short hops to visit his cousins across the road? What did they imagine the highway was? An alien presence in their midst, its function unfathomable, built by creatures that most of them had never seen? She doubted that any of them wondered about it all.
The whine of her tires on the highway was a kind of white noise, and she found that involuntarily she was–here, too–listening for a pattern. She had taken to listening closely to many sources of white noise: the motor of the refrigerator starting up in the middle of the night; the water running for her bath; the washing machine when she would do her clothes in the little laundry room off her kitchen; the roar of the ocean during a brief scuba-diving trip to the island of Cozumel off Yucatan, which she had cut short because of her impatience to get back to work. She would listen to these everyday sources of random noise and try to determine whether there were fewer apparent patterns in them than in the interstellar static.
She had been to New York City the previous August for a meeting of URSI (the French abbreviation for the International Scientific Radio Union). The subways were dangerous, she had been told, but the white noise was irresistible. In the clacka-clacka of this underground railway she had thought she heard a clue, and resolutely skipped half a day of meetings–traveling from 34th Street to Coney Island, back to midtown Manhattan, and then on a different line, out to remotest Queens. She changed trains at a station in Jamaica, and then returned a little flushed and breathless–it was, after all, a hot day in August, she told herself–to the convention hotel. Sometimes, when the subway train was banking around a steep curve, the interior bulbs would go out and she could see a regular succession of lights, glowing in electric blue, speeding by as if she were in some impossible hyper-relativistic interstellar spacecraft, hurtling through a cluster of young blue supergiant stars. Then, as the train entered a straight-away, the interior lights would come on again and she would become aware once again of the acrid smell, the jostling of nearby straphangers, the miniature television surveillance cameras (locked in protective cages and subsequently spray-painted blind), the stylized multicolored map showing the complete underground transportation system of the City of New York, and the high-frequency screech of the brakes as they pulled into the stations.
This was a little eccentric, she knew. But she had always had an active fantasy life. All right, so she was a little compulsive about listening to noise. It did no harm that she could see. Nobody seemed to notice much. Anyway, it was job-related. If she had been so minded, she could probably have deducted the expense of her trip to Cozumel from her income tax because of the sound of the breakers. Well, maybe she was becoming obsessive.
She realized with a start that she had arrived at the Rockefeller Center station. As she quickly stepped out through an accumulation of daily newspapers abandoned on the floor of the subway car, a headline of the News-Post had caught her eye: GUERRILLAS CAPTURE JOBURG RADIO. If we like them, they’re freedom fighters, she thought. If we don’t like them, they’re terrorists. In the unlikely case we can’t make up our minks, they’re temporarily only guerrillas. On an adjacent scrap of newspaper was a large photo of a florid, confident man with the headline: HOW THE WORLD WILL END. EXCERPTS FROM THE REV. BILLY JO RANKIN’S NEW BOOK. EXCLUSIVELY THIS WEEK IN THE NEWS-POST. She had taken the headlines in at a glance and tried promptly to forget them. Moving through the bustling crowds to the meeting hotel, she hoped she was in time to hear Fujita’s paper on homomorphic radio telescope design.
* * *
Superposed on the whine of the tires was a periodic thump at the joins of swathes of pavement, which had been resurfaced by different New Mexico road crews in different epochs. What if an interstellar message were being received by Project Argus, but very slowly–one bit of information every hour, say, or every week, or every decade? What if there were very old, very patient murmurs of some transmitting civilization, which had no way of knowing that we get tired of pattern recognition after seconds or minutes? Suppose they lived for tens of thousands of years. And taaaaalked verrrry slooooowwwwly. Argus would never know. Could such long-lived creatures exist? Would there have been enough time in the history of the universe for creatures who reproduced very slowly to evolve to high intelligence? Wouldn’t the statistical breakdown of chemical bonds, the deterioration of their bodies according to the Second Law of Thermodynamics, force them to reproduce about as often as human beings do? And to have lifespans like ours? Or might they reside on some old and frigid world, where even molecular collisions occur in extreme slow motion, maybe only a frame a day. She idly imagined a radio transmitter of recognizable and familiar design sitting on a cliff of methane ice, feebly illuminated by a distant red dwarf sun, while far below waves of an ammonia ocean beat relentlessly against the shore–incidentally generating a white noise indistinguishable from that of the surf at Cozumel.
The opposite was possible as well: the fast talkers, manic little creatures perhaps, moving with quick and jerky motions, who transmitted a complete radio message–the equivalent of hundreds of pages of English test–in a nanosecond. Of course, if you had a very narrow bandpass to your receiver, so you were listening only to a tiny range of frequencies, you were forced to accept the long time-constant. You would never be able to detect a rapid modulation. It was a simple consequence of the Fourier Integral Theorem, and closely related to the Heisenberg Uncertainty Principle. So, for example, if you had a bandpass of a kilohertz, you couldn’t make out a signal that was modulated at fasted than a millisecond. It would be kind of a sonic blur. The Argus bandpasses were narrower than a hertz, so to be detected the transmitters must be modulating very slowly, slower than one bit of information a second. Still slower modulations–longer than hours, say–could be detected easily, provided you were willing to point a telescope at the source for that length of time, provided you were exceptionally patient. There were so many pieces of the sky to look at, so many hundreds of billions of stars to search out. You couldn’t spend all your time on only a few of them. She was troubled that in their haste to do a full sky survey in less than a human lifetime, to listen to all of the sky at a billion frequencies, they had abandoned both the frantic talkers and the laconic plodders.
But surely, she thought, they would know better than we what modulation frequencies were acceptable. They would have had previous experience with interstellar communication and newly emerging civilizations. If there was a broad range of likely pulse rates that the receiving civilization would adopt, the transmitting civilization would utilize such a range. Modulate at microseconds, modulate at hours. What would it cost them? They would, almost all of them, have superior engineering and enormous power resources by Earth standards. If they wanted to communicate with us, they would make it easy for us. They would send signals at many different frequencies. They would use many different modulation timescales. They would know how backward we are, and would have pity.