11

On New Year’s Day, Lissa’s parents put her aboard the New York-to-Brazil air shuttle. From the Clarke Equatorial Spaceport she would boost to the interplanetary terminal complex in High Earth Orbit.

“Morey,” her mother said, “we won’t see her for over a year.”

Her father looked shaken, but he tried to remain composed as Lissa kissed him. “Take good care of yourself,” he said in a weak voice. “You may be the best brains in the family.” Lissa hugged him around the middle and turned to her mother.

Sharon was weeping.

“It won’t be so bad,” Lissa said. “As soon as you’re back in the hospital you won’t even know I’m gone.”

They embraced and held each other for a few moments. Then Lissa turned away quickly and marched through the long tunnel that led into the shuttle. She stopped at the end and glanced back, but there was no one there. They were hurrying to make their connection for the Bahamas, where they would meet two sets of parents: Morey’s and Sharon’s.

She entered the air shuttle and took a seat halfway down the aisle, putting her shoulder bag on the outer seat in the hope that no one would sit there.

* * *

The shuttle climbed until the sky became a cloudless deep blue. One hundred and ten kilometers up the engines shut down, and the craft began its effortless glide south. Lissa unhitched her belt and put her feet up on the empty seat, enjoying the calm whisper of the ship toward the equator.

She closed her eyes for a few moments and soared inwardly; when she opened them, stars shone in the purple-black over Africa’s curving horizon. I’m really going home, she thought, thinking of all the people who lived in Earth’s sky—on the Moon, around Mercury, on Mars and in the Asteroid Belt, and on the moons of Jupiter and Saturn; two and a half million in her own Bernal Clusters alone, twice that many in the O’Neill Cylinders of Sun Orbit. A starship was making its way somewhere between Sunspace and the triple star system of Centauri, 4.3 light-years away. Everywhere, human beings were transforming, building, and seeking worlds. And somewhere, beyond the worlds of human experience, were the Others, waiting to be understood. . . .

Clouds covered the small screen when she woke up. The big screen at the head of the aisle flashed:

JANUARY 1, 2081

2:17 P.M.

ETA 2:25 P.M.

She sat up and watched the descent. The shuttle dropped through the clouds into sunlight. Blue-green jungle covered the Earth. Clarke Equatorial Spaceport was just ahead. Lissa fastened her seat belt before the sign flashed.

The spaceport ahead consisted of square after square of cleared land covered with buildings, hangars, roads, walkways, hotels, launchpads, and communications dishes. Earth’s spin was fastest here on the equator—1,600 kilometers per hour—so even the most advanced launch vehicle gained some extra push into orbit.

The air shuttle came down fast. Lissa tensed as it touched the runway and began to slow. As she waited, she realized that she had become used to the Earth. Leaving it reminded her again that she was leaving Alek behind, but she pushed the fact aside as the shuttle came to a gentle stop.

She shouldered her bag and went down the aisle to the exit. A long tunnel brought her to the passport check, where she slid her card into the slot and pressed her palm down on the ID scanner. Her card popped back; she took it and went out into the terminal.

Here was a great floor filled with people coming and going from all parts of Sunspace. Many stood by their luggage and were well dressed; others looked poorer and rougher. Some had children with them. But as she looked at faces that were happy, glum, even loutish, Lissa realized that Earth was the great giver of people. This was the world from which humanity had started, and it was the world that would keep on giving people for many decades to come. It would be a long time before offworld populations would equal Earth’s billions.

Sun, sky, and a bit of jungle were visible through the giant dome. The rain forest of the Amazon was a crucial part of Earth’s recovering ecosystem, she knew, but suddenly the fact of all that green wilderness filled her with awe.

A 3-D ad flashed in her eyes:

ORBITAL TOURS!

SIGN UP NOW!

She blinked and looked away. Other signs proclaimed the advantages of shipping out as a technical apprentice to a dozen points in Sunspace. Some of the signs were shabby and ill-maintained, showing holos of power satellites beaming energy down to Earth, close-ups of robots and space-suited human workers, as well as interiors of grand orbital spas and hotels.

“Now boarding!” a woman’s voice boomed. “High Earth Orbit shuttle 714. Gate Six!”

A giant six flashed over the entrance on the far side of the waiting area. Lissa hurried across the giant floor, but paused for a few moments to read the inscription on the monument at the center:

EQUATORIAL SPACEPORT 1

OPEN FOR THE PEOPLE OF THE EARTH 2002

THE STEEL IN THIS MEMORIAL WAS MANUFACTURED OUT OF ORES MINED FROM THE FIRST ASTEROID BROUGHT INTO EARTH ORBIT 2018

Those dates seem so long ago, she thought as she hurried on toward her boarding gate.

There was a line at Gate Six, but finally she boarded the tube car. It slid forward and shot into darkness, carrying her to the launchpad two and a half kilometers away.

* * *

The lift took her up through the center of the orbiter and let her off at seat twenty-five, more than a third of the way to the ship’s nose. She climbed into her seat and watched the lift drop away, then fastened her seat belt before the sign flashed on the overhead screen. A male voice repeated the instruction.

The screen lit up, showing the orbiter standing under a blue sky. She had never taken a gravitic ship, but from what she knew it was different from a nuclear pulser. Grav launchers were still much more expensive in power requirements, but they were slowly replacing the older designs.

She heard a whining sound.

“Gravity inside the ship,” a woman’s voice explained, “will increase to about five times normal. Then the ship will be released by the reversing field, at which time you will become weightless. Please turn off the view screen if you find takeoffs distressing. Thank you.”

The high-pitched whine grew louder. Vast amounts of power, she knew, were rushing in to sustain the reverse g-force. Her seat adjusted to face the screen, and she felt her body pushing back into the cushions.

The blue sky seemed to flow on the screen. She felt a moment of anxiety as the ship was hurled upward. It seemed to dive down into the blue as the invisible cone of negative gravity pushed the vessel away from Earth. She was falling as the ship climbed. The launcher on the ground was screaming after its lost craft. 3-Ds of Brazil and a sparkling ocean flashed up on the screen, followed by the glowing curve of the planet’s horizon and the stars beyond. She was swimming out of an ocean of air into a lighted Sunspace, drifting weightlessly against her strap, waiting for her stomach to calm. All of South America was coming into view. Alek was on the other side of the globe, hidden in the furrows of the Himalayas. The sudden thought of him there, in those ancient wrinkles, filled her with regret.

* * *

Lissa awoke. The asteroid hollow in High Earth Orbit was on the screen, looking like a huge potato roasting in the sun. She looked carefully and saw dozens of black caves, where the big solar-system ships docked for repairs and service, and to take on passengers, supplies, and cargo. Inside the asteroid’s hollow were hotels, stores, warehouses, labs, and clinics. The place had been made from the first asteroid that had been maneuvered into Earth Orbit for mining in 2018. When those operations had exhausted the ores, the huge rock became a vital way station.

The shuttle turned toward one of the cavelike openings and made its approach. The opening grew larger, until Lissa could see inside. The dock was much larger than the ship. Lights blinked on as the shuttle floated inside and was secured.

Lissa waited for a few moments, then slipped her bag over her shoulder and floated out into the passageway, which was now a zero-g corridor. She saw a few of the other passengers floating toward the tail exit. She pulled herself along, wondering if she would have a chance to see the High Orbit hollow before making her connection with the Mars ship.

“There you are!” Dr. Shastri shouted as she floated out into the receiving area.

“Dr. Shastri, what are you doing here?”

“I’ll be traveling with you. We’ve got to hurry. The ship is on a tight schedule. No stopovers, I’m afraid.”

He motioned to the nearest empty tube car. She strapped in next to him, feeling disappointed that she would not be able to explore the great interplanetary terminal. She looked around anxiously, taking in the spherical reception area, from which tubeways led in all directions. The brightly lit space was filled with floating passengers making their way to waiting vehicles.

“The ship is being held for us,” Dr. Shastri said as the open tube car shot into the tunnel. “We’re the last ones to load.”

“Why the hurry?” Lissa asked.

“Important things are happening. We must get to the remote station by a certain time.”

“Why, what’s happened?”

“Yes, yes, you’ll learn shortly.”

“There’s been a breakthrough!” she said, her mind racing. Something new, after all these years! The signal had been decoded and understood, and she had not helped make it happen. “What does it say?” she demanded, feeling both elation and some disappointment.

Dr. Shastri shook his head. “It’s not that. Other things. Please be patient.”

The car glided into another receiving area. Lissa glimpsed the Mars ship through a large transparent partition. The vessel was a 300-meter-long cylinder with large globes at each end. It floated in its cradle, lit up by the glare of white lights.

“It’s a middle-aged torchship,” Dr. Shastri said, “but it’s been completely overhauled. Another will follow us in a week or two with a team of mechanics and maintenance workers. We’re recruiting them now.”

“What’s going on?” Lissa asked as they waited to board the ship.

Dr. Shastri smiled. “Not until we leave. Ask me then.”

She was glad to be excited and curious, but she felt a bit guilty. Worrying about Alek was a small, petty thing compared to what Dr. Shastri might reveal to her. But Alek would want her to be excited, she told herself silently as the car glided into the ship.

* * *

Her cabin was on deck four. She stowed her bag and strapped down on the bunk. As she waited for acceleration to start, she tried to rid herself of all self-pity. She was fortunate enough to be part of a great cultural and scientific adventure, one in which some kind of progress was being made at this very moment, despite the critics.

The small screen above her bunk lit up, showing the open way that led out of the asteroid. Stars shone in the circle of blackness. Slowly, the ship stirred, and she felt the nudge of acceleration pressing her gently into the bunk.

The circle of starry blackness expanded, and suddenly the ship escaped into the sea of space. She imagined a whale carrying her to Mars. For most of a week she would live inside its body.

Her weight increased, and finally the green light went on over the screen, signaling that one-g was now steady. All the ship’s decks now had a normal press of simulated gravity, due to the ship’s constant acceleration. The sense of weight would remain the same even though velocity would continue to increase. The nuclear torch could push the ship to velocities of over 200,000 meters per second. Other ships were even faster, she knew, but it was this kind of ship that had made the solar system smaller, in travel time, than the Renaissance Earth of Columbus.

She unstrapped, got up from the bunk, and looked around. The cabin was some three meters square. The walls and floor were made of ceramic. Besides the bunk, there were a half dozen drawers in one wall, a fold-down desk with screen and keyboard, phone included. A slide door led into a small bath-shower and toilet. A small overhead grill let in fresh air from the ship’s recycler. It was certainly not a luxury liner, she thought as she looked around at the green decor.

She sat down on the bunk, feeling strangely disappointed and suspicious about what she was getting herself into. After a moment she got up, opened the folding desk, and punched in a call to Earth, hoping to catch Alek in his room.

The screen lit up:

SECURITY RESTRICTION

She tried again, but all outgoing calls were blocked.

Her door buzzed.

“Come in,” she said, feeling annoyed.

The door slid open. “May I come in?” Dr. Shastri asked.

She nodded. “Why are the phones restricted?”

“Whom did you wish to call?”

“Alek Calder.”

“I’m afraid you won’t be able to call anyone, and I regret the necessity. But let me explain.”

She retreated to the bunk. He sat down at the desk.

“I’m sure you will understand,” he began. “U.N. Earth Authority is keeping this all under wraps. You see, we’ve now deciphered part of the alien message. At least we think so.” He paused.

“And?” Lissa asked. “What does it say?”

“It’s a picture—more of a diagram—of our Sunspace, showing the Opik-Oort halo of comets that surrounds our solar system. The diagram seems to suggest that when the halo of cometary material is disturbed, then thousands, perhaps millions of comets may plunge into the inner solar system. It would take only a few to devastate the Earth. As you know, this influx from the Oort Cloud has occurred in the past, roughly once every thirty million years. The mass extinctions recorded in geologic rock strata suggest this.”

Lissa felt a twinge of fear. “Do you think the signal is warning us that the danger is coming soon?”

“Perhaps,” Dr. Shastri said with a sigh. “But if it comes, there may be little we can do about it. There may be as many as a hundred billion comets and asteroids in the Opik-Oort Cloud. We might deflect a few, even several at a time, but not a swarm. The next two centuries may pose a threat to our whole Sunspace civilization. Earth may not survive. The free habitats have the best chance, of course, but most of Earth’s billions of people would perish.”

Lissa was silent, unable to imagine the end of all human history. It seemed impossible that it could happen.

“And you think we’re actually being warned?” she asked.

“We can’t be absolutely certain, of course, but it seems so. And it appears we know the source of the signal. The coordinates lie in the outer solar system, where there doesn’t seem to be anything on the visual wavelengths.”

Lissa felt a twist in her thinking. She wanted to probe all the possibilities. “But why is the signal’s origin so near?”

“So that it would reach us quickly, given the slowness of radio waves. Maybe they had to be sure that we would receive the warning, given that we haven’t yet shown that we can send or receive tachyons.”

Lissa’s mind seized a conclusion. “Radio—perhaps they’re also trying to be discreet, by sending a signal that only we would notice. It wouldn’t travel far in the time we’ve been receiving it. Radio is probably no more advanced than jungle drums to an advanced civilization, so they wouldn’t notice someone trying to talk to us in that way.”

“You may be right. Perhaps someone is not supposed to give us a warning, but they wanted to do it.” Dr. Shastri smiled. “It’s still all guesswork, of course. I wonder who they might be, and how distant is their home world? The signal source may be only a relay.”

“One alien power doesn’t want us to be contacted,” Lissa said, “while another is doing it. I wonder why they care, either way?”

Dr. Shastri looked at her knowingly, and again Lissa knew what to say. It was almost as if she were remembering it, listening to some lost memory. “Well, I guess now’s the time to go out and find the source of the signal, given that we know where it is.”

Dr. Shastri nodded. “We’ll be taking the remote station out there to do just that, and work will continue on the tachyon receiver-transmitter as we go. It’ll be a long journey, and we’ll be out there for months. Perhaps if we find the source of the signal, we’ll learn something useful to our survival. It’s better than spending the coming decades watching for incoming cometary bodies.”

“But they may not come for centuries, even thousands of years. We’ll have time to prepare.”

“True. Or they may have already come, and this is an old warning. We don’t know on what time scale the nurturers, if we may call them that, are trying to warn us. Centuries may be only moments to them. We’ll have to go out and learn what we can.”

“How many people are going?” she asked.

“There are already some four hundred people inside the small hollow asteroid. More are on the way on this and other ships. We’ve tried to pick a cross section of the best student and professional minds.” He looked at her intently. “You will be given a chance to go home if you change your mind before we move the station into its outward course. You’ll be asked to keep silent. As far as anyone knows, the asteroid is leaving on a routine exploratory mission into the outer solar system. Nothing of our suspicions must get out until we know more. Now, if you’ll excuse me, I have to go tell your colleague, Susan Falleta, what I have told you.”

“Susan’s aboard?” Lissa asked, feeling glad.

“Yes, she just made it.” He stood up, the door opened, and he was gone.

Lissa leaned back in the bunk and imagined what was going to happen. She reached out mentally and saw the great darkness of outer Sunspace, where the Sun was only a bright star, where countless dark worlds circled the Sun in slow orbits. The cometary halo was a great reef around the solar system, the last barrier before the ocean of interstellar space.

Something had put a transmitter out there, to whisper a warning across the short radio distance to the islands of life that were the inner planets. That someone or something had chosen radio to conceal its act of mercy. Radio was enough for such a short astronomical distance, ensuring that the signal would be noticed by a civilization that as yet had no other means of communicating across light-years.

Another idea came to her, like a friend with a warning. If this was all true, she thought, then something out in the galaxy may not like us, while something else thinks enough of us to want to help. And this was probably the first time in human history that a warning of this kind had not fallen on deaf ears.