The signals from space began a little after midnight, local time, on a Friday. They were first picked up in the South Pacific, just westward of the International Date Line. A satellite-watching station on an island named Kalua was the first to receive them, though nobody heard the first four or five minutes. But it is certain that the very first message was picked up and recorded by the monitor instruments.

The satellite-tracking unit on Kalua was practically a duplicate of all its fellows. There was the station itself with a vertical antenna outside pointing at the stars. There were various lateral antennae held two feet above ground by concrete posts. In the instrument room in the building a light burned over a desk, three or four monitor lights glowed dimly to indicate that the self-recording instruments were properly operating, and there was a multiple-channel tape recorder built into the wall. Its twin tape reels turned sedately, winding a brown plastic ribbon from one to the other at a moderate pace.

The staff man on duty had gone to the installation's kitchen for a cup of coffee. No sound originated in the room, unless one counted the fluttering of a piece of weighted-down paper on the desk. Outside, palm trees whispered and rustled their long fronds in the southeast trade wind under a sky full of glittering stars. Beyond, there was the dull booming of surf upon the barrier reef of the island. But the instruments made no sound. Only the tape reels moved.

The signals began abruptly. They came out of a speaker and were instantly recorded. They were elfin and flutelike and musical. They were crisp and distinct. They did not form a melody, but nearly all the components of melody were there. Pure musical notes, each with its own pitch, all of different lengths, like quarter-notes and eighth-notes in music. The sounds needed only rhythm and arrangement to form a plaintive tune.

Nothing happened. The sounds continued for something over a minute. They stopped long enough to seem to have ended. Then they began again.

When the staff man came back into the room with a coffee cup in his hand, he heard the flutings instantly. His jaw dropped. He said, "What the hell?" and went to look at the instruments. He spilled some of his coffee when he saw their readings.

The tracking dials said that the signals came from a stationary source almost directly overhead. If they were from a stationary source, no plane was transmitting them. Nor could they be coming from an artificial satellite. A plane would move at a moderate pace across the sky. A satellite would move faster. Much faster. This source, according to the instruments, did not move at all.

The staff man listened with a blank expression on his face. There was but one rational explanation, which he did not credit for an instant. The reasonable answer would have been that somebody, somewhere, had put a satellite out into an orbit requiring twenty-four hours for a circuit of the earth, instead of the ninety to one-hundred-twenty-four-minute orbits of the satellites known to sweep around the world from west to east and pole to pole. But the piping, musical sounds were not the sort of thing that modern physicists would have contrived to carry information about cosmic-particle frequency, space temperature, micrometeorites, and the like.

The signals stopped again, and again resumed. The staff man was galvanized into activity. He rushed to waken other members of the outpost. When he got back, the signals continued for a minute and stopped altogether. But they were recorded on tape, with the instrument readings that had been made during their duration. The staff man played the tape back for his companions.

They felt as he did. These were signals from space where man had never been. They had listened to the first message ever to reach mankind from the illimitable emptiness between the stars and planets. Man was not alone. Man was no longer isolated. Man....

The staff of the tracking station was very much upset. Most of the men were white-faced by the time the taped message had been re-played through to its end. They were frightened.

Considering everything, they had every reason to be.

The second pick-up was in Darjeeling, in northern India. The Indian government was then passing through one of its periods of enthusiastic interest in science. It had set up a satellite-observation post in a former British cavalry stable on the outskirts of the town. The acting head of the observing staff happened to hear the second broadcast to reach Earth. It arrived some seventy-nine minutes after the first reception, and it was picked up by two stations, Kalua and Darjeeling.

The Darjeeling observer was incredulous at what he heard—five repetitions of the same sequence of flutelike notes. After each pause—when it seemed that the signals had stopped before they actually did so—the reception was exactly the same as the one before. It was inconceivable that such a succession of sounds, lasting a full minute, could be exactly repeated by any natural chain of events. Five repetitions were out of the question. The notes were signals. They were a communication which was repeated to be sure it was received.

The third broadcast was heard in Lebanon in addition to Kalua and Darjeeling. Reception in all three places was simultaneous. A signal from a nearby satellite could not possibly have been picked up so far around the Earth's curvature. The widening of the area of reception, too, proved that there was no new satellite aloft with an orbit period of exactly twenty-four hours, so that it hung motionless in the sky relative to Earth. Tracking observations, in fact, showed the source of the signals to move westward, as time passed, with the apparent motion of a star. No satellite of Earth could possibly exist with such an orbit unless it was close enough to show a detectable parallax. This did not.

A French station picked up the next batch of plaintive sounds. Kalua, Darjeeling, and Lebanon still received. By the time the next signal was due, Croydon, in England, had its giant radar-telescope trained on the part of the sky from which all the tracking stations agreed the signals came.

Croydon painstakingly made observations during four seventy-nine-minute intervals and four five-minute receptions of the fluting noises. It reported that there was a source of artificial signals at an extremely great distance, position right ascension so-and-so, declination such-and-such. The signals began every seventy-nine minutes. They could be heard by any receiving instrument capable of handling the microwave frequency involved. The broadcast was extremely broad-band. It covered more than two octaves and sharp tuning was not necessary. A man-made signal would have been confined to as narrow a wave-band as possible, to save power for one reason, so it could not be imagined that the signal was anything but artificial. Yet no Earth science could have sent a transmitter out so far.

When sunrise arrived at the tracking station on Kalua, it ceased to receive from space. On the other hand, tracking stations in the United States, the Antilles, and South America began to pick up the cryptic sounds.

The first released news of the happening was broadcast in the United States. In the South Pacific and India and the Near East and Europe, the whole matter seemed too improbable for the notification of the public. News pressure in the United States, though, is very great. Here the news rated broadcast, and got it.

That was why Joe Burke did not happen to complete the business for which he'd taken Sandy Lund to a suitable, romantic spot. She was his secretary and the only permanent employee in the highly individual business he'd begun and operated. He'd known her all his life, and it seemed to him that for most of it he'd wanted to marry her. But something had happened to him when he was quite a small boy—and still happened at intervals—which interposed a mental block. He'd always wanted to be romantic with her, but there was a matter of two moons in a strange-starred sky, and trees with foliage like none on Earth, and an overwhelming emotion. There was no rational explanation for it. There could be none. Often he'd told himself that Sandy was real and utterly desirable, and this lunatic repetitive experience was at worst insanity and at the least delusion. But he'd never been able to do more than stammer when talk between them went away from matter-of-fact things.

Tonight, though, he'd parked his car where a river sparkled in the moonlight. There was a scent of pine and arbutus in the air and a faint thread of romantic music came from his car's radio. He'd brought Sandy here to propose to her. He was doggedly resolved to break the chains a psychological oddity had tied him up in.

He cleared his throat. He'd taken Sandy out to dinner, ostensibly to celebrate the completion of a development job for Interiors, Inc. Burke had started Burke Development, Inc., some four years out of college when he found he didn't like working for other people and could work for himself. Its function was to develop designs and processes for companies too small to have research-and-development divisions of their own. The latest, now-finished, job was a wall-garden which those expensive interior decorators, Interiors, Inc., believed might appeal to the very rich. Burke had made it. It was a hydroponic job. A rich man's house could have one or more walls which looked like a grassy sward stood on edge, with occasional small flowers or even fruits growing from its close-clipped surface.[A]

It was done. A production-job room-wall had been shipped and the check for it banked. Burke had toyed with the idea that growing vegetation like that might be useful in a bomb shelter or in an atomic submarine where it would keep the air fresh indefinitely. But such ideas were for the future. They had nothing to do with now. Now Burke was going to triumph over an obsessive dream.

"I've got something to say, Sandy," said Burke painfully.

She did not turn her head. There was moonlight, rippling water, and the tranquil noises of the night in springtime. A perfect setting for what Burke had in mind, and what Sandy knew about in advance. She waited, her eyes turned away from him so he wouldn't see that they were shining a little.

"I'm something of an idiot," said Burke, clumsily. "It's only fair to tell you about it. I'm subject to a psychological gimmick that a girl I—Hm." He coughed. "I think I ought to tell you about it."

"Why?" asked Sandy, still not looking in his direction.

"Because I want to be fair," said Burke. "I'm a sort of crackpot. You've noticed it, of course."

Sandy considered.

"No-o-o-o," she said measuredly. "I think you're pretty normal, except—No. I think you're all right."

"Unfortunately," he told her, "I'm not. Ever since I was a kid I've been bothered by a delusion, if that's what it is. It doesn't make sense. It couldn't. But it made me take up engineering, I think, and ..."

His voice trailed away.

"And what?"

"Made an idiot out of me," said Burke. "I was always pretty crazy about you, and it seems to me that I took you to a lot of dances and such in high school, but I couldn't act romantic. I wanted to, but I couldn't. There was this crazy delusion...."

"I wondered, a little," said Sandy, smiling.

"I wanted to be romantic about you," he told her urgently. "But this damned obsession kept me from it."

"Are you offering to be a brother to me now?" asked Sandy.

"No!" said Burke explosively. "I'm fed up with myself. I want to be different. Very different. With you!"

Sandy smiled again.

"Strangely enough, you interest me," she told him. "Do go on!"

But he was abruptly tongue-tied. He looked at her, struggling to speak. She waited.

"I w-want to ask you to m-m-marry me," said Burke desperately. "But I have to tell you about the other thing first. Maybe you won't want...."

Her eyes were definitely shining now. There was soft music and rippling water and soft wind in the trees. It was definitely the time and place for romance.

But the music on the car radio cut off abruptly. A harsh voice interrupted:

"Special Bulletin! Special Bulletin! Messages of unknown origin are reaching Earth from outer space! Special Bulletin! Messages from outer space!"

Burke reached over and turned up the sound. Perhaps he was the only man in the world who would have spoiled such a moment to listen to a news broadcast, and even he wouldn't have done it for a broadcast on any other subject. He turned the sound high.

"This is a special broadcast from the Academy of Sciences in Washington, D. C." boomed the speaker. "Some thirteen hours ago a satellite-tracking station in the South Pacific reported picking up signals of unknown origin and great strength, using the microwave frequencies also used by artificial satellites now in orbit around Earth. The report was verified shortly afterward from India, then Near East tracking stations made the same report. European listening posts and radar telescopes were on the alert when the sky area from which the signals come rose above the horizon. American stations have again verified the report within the last few minutes. Artificial signals, plainly not made by men, are now reaching Earth every seventy-nine minutes from remotest space. There is as yet no hint of what the messages may mean, but that they are an attempt at communication is certain. The signals have been recorded on tape, and the sounds which follow are those which have been sent to Earth by alien, non-human, intelligent beings no one knows how far away."

A pause. Then the car radio, with night sounds and the calls of nightbirds for background, gave out crisp, distinct fluting noises, like someone playing an arbitrary selection of musical notes on a strange wind instrument.

The effect was plaintive, but Burke stiffened in every muscle at the first of them. The fluting noises were higher and lower in turn. At intervals, they paused as if between groups of signals constituting a word. The enigmatic sounds went on for a full minute. Then they stopped. The voice returned:

"These are the signals from space. What you have heard is apparently a complete message. It is repeated five times and then ceases. An hour and nineteen minutes later it is again repeated five times...."

The voice continued, while Burke remained frozen and motionless in the parked car. Sandy watched him, at first hopefully, and then bewilderedly. The voice said that the signal strength was very great. But the power for artificial-satellite broadcasts is only a fraction of a watt. These signals, considering the minimum distance from which they could come, had at least thousands of kilowatts behind them.

Somewhere out in space, farther than man's robot rockets had ever gone, huge amounts of electric energy were controlled to send these signals to Earth. Scientists were in disagreement about the possible distance the signals had traveled, whether they were meant solely for Earth or not, and whether they were an attempt to open communication with humanity. But nobody doubted that the signals were artificial. They had been sent by technical means. They could not conceivably be natural phenomena. Directional fixes said absolutely that they did not come from Mars or Jupiter or Saturn. Neptune and Uranus and Pluto were not nearly in the line of the signals' travel. Of course Venus and Mercury were to sunward of Earth, which ruled them out, since the signals arrived only on the night side of mankind's world. Nobody could guess, as yet, where they did originate.

Burke sat utterly still, every muscle tense. He was so pale that even in the moonlight Sandy saw it. She was alarmed.

"Joe! What's the matter?"

"Did you—hear that?" he asked thinly. "The signals?"

"Of course. But what...."

"I recognized them," said Burke, in a tone that was somehow despairing. "I've heard signals like that every so often since I was a kid." He swallowed. "It was sounds like that, and what went with them, that has been the—trouble with me. I was going to tell you about it—and ask you if you'd marry me anyway."

He began to tremble a little, which was not at all like the Joe Burke that Sandy knew.

"I don't quite under—"

"I'm afraid I've gone out of my head," he said unsteadily. "Look, Sandy! I was going to propose to you. Instead, I'm going to take you back to the office. I'm going to play you a recording I made a year ago. I think that when you've heard it you'll decide you wouldn't want to marry me anyhow."

Sandy looked at him with astonished eyes.

"You mean those signals from somewhere mean something special to you?"

"Very special," said Burke. "They raise the question of whether I've been crazy, and am suddenly sane, or whether I've been sane up to now, and have suddenly gone crazy."

The radio switched back to dance music. Burke cut it off. He started the car's motor. He backed, swung around, and headed for the office and construction shed of Burke Development, Inc.

Elsewhere, the profoundest minds of the planet gingerly examined the appalling fact that signals came to Earth from a place where men could not be. A message came from something which was not human. It was a suggestion to make cold chills run up and down any educated spine. But Burke drove tensely, and the road's surface sped toward the car's wheels and vanished under them. A warm breeze hummed and thuttered around the windshield. Sandy sat very still.

"The way I'm acting doesn't make sense, does it?" Burke asked. "Do you feel like you're riding with a lunatic?"

"No," she said. "But I never thought that if you ever did get around to asking me to marry you, somebody from outer space would forbid the banns! Can't you tell me what all this is about?"

"I doubt it very much," he told her. "Can you tell me what the signals are about?"

She shook her head. He drove through the night. Presently he said, "Aside from my private angle on the matter, there are some queer things about this business. Why should somebody out in space send us a broadcast? It's not from a planet, they say. If there's a spaceship on the way here, why warn us? If they want to be friends, they can't be sure we'll permit it. If they intend to be enemies, why throw away the advantage of surprise? In either case, it would be foolish to send cryptic messages on ahead. And any message would have to be cryptic."

The car went whirring along the roadway. Soon twinkling lights appeared among the trees. The small and larger buildings of Burke Development, Inc., came gradually into view. They were dark objects in a large empty space on the very edge of Burke's home town.

"And why," he went on, "why send a complex message if they only wanted to say that they were space travelers on the way to Earth?"

The exit from the highway to Burke Development appeared. Burke swung off the surfaced road and into the four-acre space his small and unusual business did not begin to fill up.

"If it were an offer of communication, it should be short and simple. Maybe an arithmetic sequence of dots, to say that they were intelligent beings and would like the sequence carried on if we had brains, too. Then we'd know somebody friendly was coming and wanted to exchange ideas before, if necessary, swapping bombs."

The car's headlights swept over the building in which the experimental work of Burke Development was done and on to the small house in which Sandy kept the books and records of the firm. Burke put on the brakes before the office door.

"Just to see if my head is working right," he said, "I raise a question about those signals. One doesn't send a long message to emptiness, repeated, in the hope that someone may be around to catch it. One calls, and sends a long message only when the call is answered. The call says who's wanted and who's calling, but nothing more. This isn't that sort of thing."

He got out of the car and opened the door on her side, then unlocked the office door and went in. He switched on the lights inside. For a moment, Sandy did not move. Then she slowly got out of the car and entered the office which was so completely familiar. Burke bent over the office safe, turning the tumbler-wheel to open it. He said over his shoulder, "That special bulletin will be repeated on all the news broadcasts. You've got a little radio here. Turn it on, will you?"

Again slowly, Sandy crossed the office and turned on the miniature radio on her desk. It warmed up and began to make noises. She dimmed it until it was barely audible. Burke stood up with a reel of brown tape. He put it on the office recorder, usually used for the dictation of the day's lab log.

"I have a dream sometimes," said Burke. "A recurrent dream. I've had it every so often since I was eleven. I've tried to believe it was simply a freak, but sometimes I've suspected I was a telepath, getting some garbled message from somewhere unguessable. That has to be wrong. And again I've suspected that—well—that I might not be completely human. That I was planted here on Earth, somehow, not knowing it, to be of use to—something not of Earth. And that's crazy. So I've been pretty leery of being romantic about anybody. Tonight I'd managed to persuade myself all those wild imaginings were absurd. And then the signals came." He paused and said unsteadily, "I made this tape a year ago. I was trying to convince myself that it was nonsense. Listen. Remember, I made this a year ago!"

The reels began to spin on the recorder's face. Burke's voice came out of the speaker, "These are the sounds of the dream," it said, and stopped.

There was a moment of silence, while the twin reels spun silently. Then sounds came from the recorder. They were musical notes, reproduced from the tape. Sandy stared blankly. Disconnected, arbitrary flutelike sounds came out into the office of Burke Development, Inc. It was quite correct to call them elfin. They could be described as plaintive. They were not a melody, but a melody could have been made from them by rearrangement. They were very remarkably like the sounds from space. It was impossible to doubt that they were the same code, the same language, the same vocabulary of tones and durations.

Burke listened with a peculiarly tense expression on his face. When the recording ended, he looked at Sandy.

Sandy was disturbed. "They're alike. But Joe, how did it happen?"

"I'll tell you later," he said grimly. "The important thing is, am I crazy or not?"

The desk radio muttered. It was an hourly news broadcast. Burke turned it up and a voice boomed:

"... one o'clock news. Messages have been received from space in the century's most stupendous news event! Full details will follow a word from our sponsor."

There followed an ardent description of the social advantage, personal satisfaction and business advancement that must instantly follow the use of a particular intestinal regulator. The commercial ended.

"From deepest space," boomed the announcer's voice, "comes a mystery! There is intelligent life in the void. It has communicated with us. Today—"

Because of the necessity to give the later details of a cafe-society divorce case, a torch murder and a graft scandal in a large city's municipal budget, the signals from space could not be fully treated in the five-minute hourly news program. But fifteen seconds were spared for a sample of the cryptic sounds from emptiness. Burke listened to them with a grim expression.

"I think," he said measuredly, "that I am sane. I have heard those noises before tonight. I know them—I'll take you home, Sandy."

He ushered her out of the office and into his car.

"It's funny," he said as he drove back toward the highway. "This is probably the beginning of the most important event in human history. We've received a message from an intelligent race that can apparently travel through space. There's no way in the world to guess what it will bring about. It could be that we're going to learn sciences to make old Earth a paradise. Or it could mean that we'll be wiped out and a superior race will take over. Funny, isn't it?"

Sandy said unsteadily, "No. Not funny."

"I mean," said Burke, "when something really significant happens, which probably will determine Earth's whole future, all I worry about is myself—that I'm crazy, or a telepath, or something. But that's convincingly human!"

"What do you think I worry about?" asked Sandy.

"Oh ..." Burke hesitated, then said uncomfortably, "I was going to propose to you, and I didn't."

"That's right," said Sandy. "You didn't."

Burke drove for long minutes, frowning.

"And I won't," he said flatly, after a time, "until I know it's all right to do so. I've no explanation for what's kept me from proposing to you up to now, but apparently it's not nonsense. I did anticipate the sounds that came in tonight from space and—I've always known those sounds didn't belong on Earth."

Then, driving doggedly through a warm and moonlit night, he told her exactly why the fluting sounds were familiar to him; how they'd affected his life up to now. He'd mentally rehearsed the story, anyhow, and it was reasonably well arranged. But told as fact, it was preposterous.

She listened in complete silence. He finished the tale with his car parked before the boardinghouse in which Sandy lived with her sister Pam, they being all that was left of a family. If she hadn't known Burke all her life, of course, Sandy would have dismissed him and his story together. But she did know him. It did explain why he felt tongue-tied when he wished to be romantic, and even why he recorded a weird sequence of notes on a tape recorder. His actions were reasonable reactions to an unreasonable, repeated experience. His doubts and hesitations showed a sound mind trying to deal with the inexplicable. And now that the signals from space had come, it was understandable that he should react as if they were a personal matter for his attention.

She had a disheartening mental picture of a place where strange trees waved long and ribbonlike leaves under an improbable sky. Still ...

"Y—yes," she said slowly when he'd finished his uneasy account. "I don't understand, but I can see how you feel. I—I guess I'd feel the same way if I were a man and what you've experienced happened to me." She hesitated. "Maybe there will be an explanation now, since those signals have come. They do match the ones you recorded from your dream. They're the ones you know about."

"I can't believe it," said Burke miserably, "and I can't dismiss it. I can't do anything until I find out why I know that somewhere there's a place with two moons and queer trees...."

He did not mention the part of his experience Sandy was most interested in—the person for whom he felt such anguished fear and such overwhelming joy when she was found. She didn't mention it either.

"You go on home, Joe," she said quietly. "Get a good night's sleep. Tomorrow we'll hear more about it and maybe it will all clear up. Anyhow—whatever turns out, I—I'm glad you did intend to ask me to marry you. I intended to say yes."