Three bodies

The "Halo" turned off its curvature engine and glides at the speed of light.

During the voyage, AA kept trying to comfort Cheng Xin, although she knew that this was something beyond her capabilities.She said to Cheng Xin, it's ridiculous for you to think that your own mistakes destroyed the solar system. Thinking like this is really too pretentious, just like you do a handstand on the ground and think you lifted the earth.Even if you didn't stop Vader at the time, the outcome of that war is hard to predict. Can Halo City really gain independence?Even Vader himself is not confident about this.How many antimatter bullets will the federal government and fleet really be frightened by?Maybe the guardians of Star Ring City can destroy several battleships, or even a space city, but Star Ring City will be wiped out by the Federation Fleet in the end. In this case, it may even be impossible to build a Mercury base in the future.From another point of view, even if Halo City is independent, continues the research of curvature drive and discovers the wake effect, finally cooperates with the federal government, and has enough time to build more than 1000 light-speed spaceships, but the human world will really build for itself Black field?We must know that people were already full of confidence at that time, thinking that the bunker world could escape the blow of the dark forest and survive, would they really use the black domain to isolate themselves from the universe?

AA's words slipped through Cheng Xin's mind like water droplets on a lotus leaf, leaving no trace.Cheng Xin's only hope now is to meet Yun Tianming and tell him everything.In her impression, 280 seven light years is an extremely long voyage, but the spacecraft AI told her that within the reference frame of the spacecraft, the voyage time is only 52 hours.Cheng Xin had an extremely unreal feeling. Sometimes she felt that she was dead and was in another world.

Cheng Xin watched the space at the speed of light through the porthole for a long time. She knew that every time a star jumped out of the star cluster emitting blue light in front, passed the spaceship and flew into the red star cluster behind, it meant that the "Halo" Fly by a star.She counted the stars that jumped out one after another, watched them fly by, and watched them turn from blue to red. This behavior had a strong hypnotic effect, and she finally fell asleep.

When Cheng Xin woke up, the "Halo" was already close to the target star, its hull rotated 180 degrees, and the curvature engine started to slow down in the forward direction.At this time, the spacecraft is actually pushing the trajectory forward.After the deceleration started, the blue star cluster in front and the red star cluster in the rear were gradually spreading out, like two blooming fireworks, and soon spread into a sea of ​​stars all over the sky.As speed decreases, the blues and reds produced by the Doppler effect fade away.Cheng Xin and AA saw that there was no change in the shape of the Milky Way ahead that could be detected by the naked eye, but looking back, they only saw a strange constellation of stars, and the solar system had long since disappeared.

"We are now 280 light-years away from the solar system [-]." Said the spacecraft AI.

"That is to say, 280 years have passed there?" AA asked, as if waking up from a dream.

"In that frame of reference, yes."

Cheng Xin sighed softly. For the current solar system, what is the difference between 280 years or 2806 million years?But she suddenly thought of one thing.

"There, when does the fall into two dimensions stop?"

This question also stuck AA for a while.Yeah, when will it stop?In the small two-dimensional space at the beginning, is there an instruction to stop at a certain time?Cheng Xin and AA didn't have any theoretical knowledge about two-dimensional space and the fall from three-dimensional to two-dimensional, but their intuition told them that it was unlikely. The stop command or program embedded in the two-dimensional space was really too mysterious. Not too possible.

Will the falling never stop? !

The wisest thing to do about this is to stop thinking about it.

The star DX3906 is about the size of the sun. When Halo began to decelerate, it looked like an ordinary star from the spacecraft, but when the curvature engine stopped, the star could already see the disk shape, and its light was reddish compared with the sun. .

After the "Halo" turned off the curvature engine, it started the fusion engine. The tranquility on the spacecraft was broken, and there was the buzzing sound and slight vibration of the propeller.The spacecraft AI analyzed the data just obtained by the monitoring system, and re-determined the basic situation of this galaxy: DX3906 star has two planets, both of which are solid planets, and the one farther away from the star is comparable in size to Mars, but has no atmosphere. The surface is very desolate, because of its gray color, Cheng Xin and AA called it a gray star.Another planet with a smaller orbital radius is comparable in size to Earth, and its surface features are also very similar to Earth, with an oxygen-containing atmosphere and obvious signs of life, but no traces of agricultural and industrial civilizations have been found; it appears like Earth Out of blue, they call it Blue Star.

AA was delighted that her findings were confirmed. More than 400 years ago, her PhD research project was to discover the planets of this star, which was previously thought to be a bare star without planets. It was through this that AA got to know Cheng Xin. Without these experiences, her life would be completely different.The fate is really strange. Four centuries ago, when she gazed at that distant world countless times from the astronomical telescope, she never dreamed that she would come here one day.

"Did you see these two planets at that time?" Cheng Xin asked.

"No, I can't see it in the visible light band. Maybe the telescope of the solar system early warning system can see it later. At that time, I could only analyze the data collected through the solar gravitational lens... I speculated about the appearance of these two planets, and what I see now almost."

It took only 3906 hours for the "Halo" to fly across the solar system to DX280 in the 52 six-light-year distance, but traveling from the edge of this galaxy to the terrestrial planet at sub-light speed, the distance of only [-] astronomical units took for eight full days.When the spacecraft was approaching the blue star, Cheng Xin and AA discovered that its similarity to the Earth's appearance was false.The blue color of this planet is not the color of the ocean, but the color of the vegetation on the land.The ocean on the blue star is pale yellow, and its area accounts for only one-fifth of the planet's surface area.Blue Star is a cold world. Except for about one-third of the blue area, most of its land is covered with snow, and most of the ocean is frozen. Only a small area near the equator is in a state of melting.

The "Halo" landed in the orbit of the blue star and began to descend gradually. At this time, the spacecraft AI suddenly made an important discovery: "It received an intelligent electromagnetic signal from the surface of the planet. It is a landing navigation signal. It is in the format of the early deterrence era. , accept this landing guidance?"

Cheng Xin and AA looked at each other excitedly, and Cheng Xin said, "Accept! Land according to its guidance."

"There will be 4G overweight, please enter the acceleration position, and execute the command when you are ready." AI said.

"Is that him?" AA asked excitedly.

Cheng Xin shook her head lightly. In her past life, the lucky time was just a gap between catastrophe and catastrophe. She was a little afraid of luck.

Cheng Xin and AA sat in the accelerator seat, and the seats closed like big palms, holding them between them. The "Halo" began to slow down, and its orbit dropped sharply.Soon, with a violent shock, the spacecraft entered the atmosphere of the blue star.In the picture sent back by the surveillance system, the blue and white continent filled the entire field of vision.

Ten minutes later, Halo landed on land near the equator.The spaceship AI told Cheng Xin and AA to get up from their seats after 10 minutes, so as to get used to the gravity of Blue Star and Earth being basically the same.It can be seen from the porthole and the monitoring screen that the place where the spacecraft landed is a blue grassland. Not far away, you can see the mountains covered with snow, which is already close to the foot of the mountain.The sky was yellowish, the same color as the sea seen from space, and the reddish sun was shining in the sky, it was blue star noon, but the sky and sun looked like dusk on earth.

Neither Cheng Xin nor AA carefully observed Lanxing's environment. Their attention was attracted by an aircraft parked near the "Halo".It was a small aircraft, four or five meters high, with a dark gray surface, streamlined shape, and a small tail. It didn't seem to be flying in the atmosphere, but like a shuttle between space orbit and the ground.

Standing next to the craft was a man, a man in a white jacket and dark trousers, his hair ruffled by the Halo landing draft.

"Is that him?" AA asked nervously.

Cheng Xin shook her head lightly, and from a distance, she knew that the man was not Yun Tianming.

The man walked towards the "Halo" on the blue grass waves, not walking fast, his gait and posture were a little tired, and there was no surprise or excitement, as if the appearance of the "Halo" was a A very common thing.He stopped a dozen meters away from the spaceship, stood on the grass and waited patiently.

"He's handsome," AA said.

This man looks about 40 years old, with an oriental face, he is indeed more handsome than Yun Tianming, with a broad forehead, and a pair of wise and gentle eyes, which make people feel that he is always thinking, as if including "Xinghuan" " Nothing could ever surprise him, only make him think.He raised his hands in a gesture around his head, indicating the helmet, then waved one hand and shook his head, apparently to indicate that he didn't need to wear a space suit when he left the cabin.

"Atmospheric composition: 35% oxygen, 63% nitrogen, 2% carbon dioxide, and a small amount of inert gas, which can be breathed, but the atmospheric pressure is only 0.53 Earth's standard pressure, so do not do strenuous activities after leaving the cabin." Said the spacecraft AI.

"What's that creature standing near the ship?" AA asked.

"Normal human beings." The AI ​​simply replied.

Cheng Xin and AA got up and walked out of the spaceship. They were not quite used to the gravity yet, and their steps were a little staggering.Walking out of the cabin door, breathing was smooth, and I didn't feel the thinness of the air.There was a gust of wind blowing head-on, very cold, but not harsh, and there was a smell of green grass in it, which gave them a refreshing feeling.The field of vision suddenly opened up, the blue and white land and mountains, the yellowish sky and the red sun, all of which seemed to be a fake color photo of the earth, except for the color change, everything else was the same.For example, the grass on the ground is not much different from the grass on the earth except that the color is blue.The man had come down to the gangway.

"Wait a minute, the ladder is too steep, let me help you down." The man walked briskly up the gangway as he spoke, and helped Cheng Xin go down first, "You should rest for a while before coming out, there is nothing here It's important." Cheng Xin could tell that he had an accent of Deterrence Era.

Cheng Xin felt his hands were warm and strong, and his steady body also blocked the cold wind for her.Facing this first man she met more than 200 light-years away from the solar system, she had a desire to throw herself into his arms.

"Are you from the solar system?" the man asked.

"Yes." Cheng Xin nodded, and with the man's support, she walked carefully down the gangway. Her trust in him was growing, so she put more body weight on him.

"The solar system is gone," said AA, taking a seat at the top of the gangway.

"I know, is there anyone else running out?"

At this time Cheng Xin had already descended to the ground, standing in the soft grass, she sat down wearily on the bottom step of the gangway, and shook her head at the same time, "Probably not."

"Oh..." The man nodded, and walked up the gangway to help AA, "My name is Guan Yifan, I'm really waiting for you here."

"You know we're coming?" AA said while extending his hand to Guan Yifan.

"Received your gravitational wave message."

"Are you from the Blue Space?"

"Hehe, if you ask this question to those who have just left, they must be very strange. The people on the 'Blue Space' and 'Gravity' are now the ancients four centuries ago. However, I am really an old man. Ancients, I am an on-ship researcher on the 'Gravity', I have been hibernating for four centuries, and I only woke up five years ago."

"Where are 'Blue Space' and 'Gravity' now?" Cheng Xin struggled to stand up while holding onto the railing of the gangway, and asked Guan Yifan who was helping AA down.

"at the Museum."

"Where is the museum?" AA asked, she supported Guan Yifan's shoulders, almost being hugged by him.

"In worlds one and four."

"How many worlds are there?"

"Four, and two more are in the process of pioneering."

"Where are all these worlds?"

At this time, Guan Yifan had already helped AA to the ground, he let her go, and said with a smile: "You two, no matter who you meet in the future, human beings or any other intelligent things, don't ask where their world is. Basic etiquette in this universe, like don't ask a lady's age...but I still want to ask, how old are you all?"

"You can be as big as you look, she is seven hundred years old, I am five hundred years old, that's it." AA said, sitting down on the grass.

"Dr. Cheng Xin has hardly changed from four centuries ago."

"You know her?" AA looked up at Guan Yifan and asked.

"Saw it in images received from Earth, and that was also four centuries ago."

"How many people are there on this planet?" Cheng Xin asked.

"Three, just the three of us."

"So, those worlds of yours are better than here?" AA asked in surprise.

"You mean the natural environment? Of course not. In those places, after a century of transformation, the atmosphere can barely breathe. This is a good place, the best place we have ever seen, just Dr. Cheng Xin, we welcome you Come here, but don't claim your ownership of it."

"I gave up my ownership a long time ago." Cheng Xin said, "Then why don't you immigrate here?"

"It's dangerous here, and outsiders often come here."

"Alien? Alien?" AA asked.

"Yes, there are two busy airlines in this area near the center of Orion's spiral arm."

"Then what are you doing here, just waiting for us?"

"No, I came here with an expedition team, they have already left, I will stay and wait for you."

More than ten hours later, the three ushered in the blue star night.There is no moon in the night sky, but compared with the earth, the starry sky here is much brighter. The Milky Way is like a silver sea of ​​flames, which can reflect people's shadows on the ground.In fact, compared with the solar system, it is not much closer to the center of the Milky Way. It may be that there is interstellar dust in the 280 light-year space, which makes the Milky Way seen by the solar system much dim.

Under the bright starlight, many parts of the grassland could be seen moving. Cheng Xin and AA thought it was an illusion caused by the wind at first, but found that the grass under their feet was also moving, making a subtle rustling sound.Guan Yifan told them that bluegrass can indeed move, and their roots are also feet. In different seasons of the year, the grass will migrate between different latitudes, mainly at night. Upon hearing this, AA immediately threw away the two blades of grass he was playing with.Guan Yifan said that these grasses are indeed plants, living by photosynthesis, and only have a simple sense of touch.Other plants in this world can also walk. He pointed out to them the ridges in the distance, and they could see the woods moving under the starlight. Those trees walked much faster than the grass, and they looked like an army marching at night from a distance.

Guan Yifan pointed to a direction where the stars were sparse in the night sky and said: "Look there, just a few days ago, you could still see the sun there, which is clearer than seeing our star here from the earth. Of course, it is 280 seven It was the sun years ago. The sun went out on the day the expedition left."

"The sun just doesn't shine anymore, but it has a large area, and it may be visible with a telescope from here." AA said.

"No, I can't see anything anymore." Guan Yifan shook his head, and pointed to the empty night sky, "Even if you go back there now, you won't see anything anymore, it's already an empty space with nothing left. The two-dimensional sun and planets you see are actually a kind of energy release effect of three-dimensional matter after two-dimensionalization. What you see is not just two-dimensional matter, but the refraction of electromagnetic waves released by them at the interface between two-dimensional and three-dimensional space , After the energy release is complete, everything is invisible, and the two-dimensional solar system and the three-dimensional world have lost contact forever."

"How could it be? You can see the three-dimensional world in the four-dimensional space." Cheng Xin said.

"Yes, I have seen [-]D from [-]D, but [-]D cannot see [-]D, because [-]D has thickness, and there is a dimension that can block and scatter light from [-]D, so I can see from [-]D; but [-]D does not Thickness, light in the three-dimensional world can pass through completely, so the two-dimensional world is completely transparent and impossible to see.”

"Can't you see it by any means?" AA asked.

"Can't see it, and it's theoretically impossible to see it."

Cheng Xin and AA were silent for a long time.The solar system had completely disappeared, and the only sustenance they had on their mother's world was nonexistent.But Guan Yifan immediately gave them a little comfort:

"From the three-dimensional world, the existence of the two-dimensional solar system can be detected by only one thing: gravity. The gravitational force of the two-dimensional solar system still acts on the three-dimensional world, so there should be a completely invisible gravity in that empty space source."

Cheng Xin and AA looked at each other thoughtfully.

"Somewhat familiar, isn't it [75]?" Guan Yifan asked with a smile, and he changed the subject immediately, "Let's talk about the date you two went on."

"Do you know Yun Tianming?" AA asked.

"do not know."

"Where's the Trisolaran fleet?" Cheng Xin asked.

"Not much is known either. Trisolaran First Fleet and Second Fleet may never meet. More than 60 years ago, a large-scale battle broke out near Taurus. It was so tragic that the wreckage formed a new cloud of dust. We can It is certain that one of them is the Trisolaran Second Fleet, but it is not known who the other party is, and the outcome of the battle is also unclear."

"Where's the First Fleet?" Cheng Xin asked with concern, her eyes shining in the starlight.

"I don't know, there is no news... You can't stay here for too long, this is not a safe place. Come with me, go to our world, where the pioneering era is over and life is starting to get better."

"I agree!" AA said, and then took Cheng Xin's arm, "Let's go with him. If you wait here for the rest of your life, the biggest possibility is that you won't be able to wait for anything. Life can't be all about waiting, right?"

Cheng Xin nodded silently, she knew that what she was chasing was a dream.

They decided to stay in Blue Star for another day before setting sail and leaving.

Guan Yifan has a small spaceship parked in the blue star's synchronous orbit.The spaceship is small and has no name, only a serial number, but Guan Yifan called it "Hunter", saying that it was to commemorate a friend who was on the "Gravity" more than 400 years ago. There is no ecological cycle system on the "Hunter", and the crew can only hibernate if they sail for a long time. Although the volume of the "Hunter" is only a few tenths of that of the "Halo", it is also a light-speed spaceship driven by curvature.When they decided to leave, Guan Yifan also took the "Halo" and let the "Hunter" sail unmanned.Cheng Xin and AA didn't ask about the route, and even Guan Yifan avoided answering the question about the sailing time, which shows that he is extremely cautious about the location of the human world.

On this day, the three of them took a short trip near the Halo.For Cheng Xin, AA, and the extinct humans in the solar system, this means many firsts: the first time to sail to a star system outside the solar system, the first time to set foot on a planet outside the solar system, and the first time to enter a solar system the living world outside.

Compared with the earth, the ecosystem on the blue star is very simple. In addition to the blue migratory plants, there are not many kinds of fish in the ocean. There are no higher animals on land, only simple small insects, much like a simplified version of the Earth.Earth's plants can grow in this world, so even without any technology, earth humans can survive in this world.

Guan Yifan entered the "Halo" and expressed his sincere admiration for this exquisite interstellar spacecraft. He said that for humans in the galaxy, there is one thing that humans in the solar system cannot inherit or learn, and that is the taste of life .He lingered in those beautiful small courtyards for a long time, indulging in the majestic landscape of the holographic image of the earth. At this time, he was still thinking, but his eyes were a little moist.

During this time, Ai AA always looked at Guan Yifan affectionately from the sidelines.On this day, the relationship between them has made subtle progress.During the trip, AA always managed to get close to Guan Yifan, and when the latter spoke, she always listened attentively, smiling and nodding from time to time.She had never behaved like this in front of any man before.In the centuries since she met Cheng Xin, AA had had countless lovers, and often had more than two at the same time—this is a normal state of life in the new era, but Cheng Xin knew that AA had never really loved a man. .Now, she's clearly in love with this cosmologist from the Deterrence Age.Cheng Xin was very pleased about this. After arriving in the new world, Ai AA should have a wonderful new life.

As for herself, Cheng Xin knew that she was spiritually dead, and the only hope for her spirit to continue to live was Yun Tianming, and now this hope was in vain.In fact, a date in 280 six light-years away, four centuries later, would have been nothing.Physically, of course she will survive, but that is only a duty to avoid halving the population of the remaining earth civilization.

Blue Star's night fell again, and they decided to set sail at dawn the next day.

At midnight, Guan Yifan, who was sleeping soundly on the "Halo", was awakened by the beeping of the communicator on his left wrist, which was a call from the "Hunter" in the synchronous orbit. The "Hunter" forwarded the information of the surveillance satellite; the expedition team left behind three small surveillance satellites, of which No. [-] and No. [-] satellites are deployed in the blue star orbit, and No. [-] revolves around another planet in this galaxy—— The gray star is running, and this information comes from the No. [-] satellite.

35 minutes ago, a spacecraft of unknown origin landed on the surface of the gray star. This is a formation of five aircraft.Only twelve minutes later, these spacecraft simultaneously took off from the surface of the gray star, and quickly disappeared without even observing them enter the orbit of the planet.The satellite may have been severely jammed, returning only blurry images.

The mission of the expedition team that Guan Yifan belongs to is to find and study the traces left by alien civilizations in this galaxy.After receiving the information from the surveillance satellite, he immediately decided to take the "Hunter" to the Gray Star to investigate.Cheng Xin strongly demanded to go with him, Guan Yifan firmly refused at first, but agreed after hearing a word from AA:

"Let her go, she must want to know if this has something to do with Yun Tianming."

Before leaving, Guan Yifan repeatedly told AA not to communicate with the "Hunter" unless there is an emergency, because no one knows what alien things are hidden in this galaxy, and communication will reveal their whereabouts.

In this lonely world where there are only three people, even a brief separation is an exciting thing. AA hugs Cheng Xin and Guan Yifan to say goodbye, wishing them peace.Before boarding the shuttle, Cheng Xin looked back and saw AA standing in the watery starlight and waving to them. A large swath of bluegrass surged past her, and the cold wind blew her short hair, making waves on the moving grass. ripple.

The shuttle took off, and in the surveillance screen, Cheng Xin saw a large area of ​​grass lit up by the flames of the propellers, and the bluegrass in the flames scattered and fled in all directions.As the shuttle ascended, the illuminated area on the ground quickly darkened, and then, the far away land was once again immersed in starlight.

An hour later, the shuttle docked with the "Hunter" on the synchronous orbit. The shape of the spacecraft was tetrahedron, like a small pyramid, and the interior was very narrow without any decorations. The hibernation cabin for four people took up a large part space.

Like the "Halo", the "Hunter" is also a dual-power configuration of curvature drive and fusion engine. It can only use the fusion engine during interplanetary navigation, because the curvature engine will make the spacecraft pass the target planet as soon as it is started, and it is too late. slow down.After the fusion engine started, the "Hunter" left the orbit of the blue star and flew to the gray star, which is still only a bright spot.In order to take care of Cheng Xin, Guan Yifan only limited the acceleration overload to about 1.5G at first, but Cheng Xin advised him not to worry about her and to go as fast as possible, so he increased the acceleration.The blue flame of the propeller was doubled, and the overload reached 3G: under such an overweight, they could only be deeply trapped in the accelerator seat and could not move.Guan Yifan switched to the panoramic display, and the spaceship completely disappeared from their surroundings. They were suspended in space, watching the blue star gradually move away.At this time, Cheng Xin felt that the gravity of 3G came from the blue star, and this gravity gave the space a sense of direction up and down, and they were flying towards the Milky Way above.

The overweight of 3G has little effect on speaking, and they chatted naturally.Cheng Xin asked Guan Yifan why he had hibernated for so long, and he told Cheng Xin that during the voyage to find an inhabitable world, he was not on duty and hibernated all the time.After the two ships discovered the habitable world No. [-], the main life was pioneering and construction. The settlement was like a small village in the agricultural era.At this time, there was no environment and conditions for carrying out scientific research, and the New World government passed a resolution to let all basic scientists hibernate until they were able to carry out basic research. He is the only basic scientist on "Gravity", but there are seven scholars on "Blue Space".Of these hibernators, he was the last to wake up, nearly two centuries after the two ships reached World One.

Cheng Xin was fascinated by Guan Yifan's introduction to the human world, but she noticed that Guan Yifan talked about world No. [-], No. [-] and No. [-], but never mentioned No. [-] world.

"I have never been to World No. [-]. No one has been there, or it is impossible for those who have been there to come back from there. That world is in the Tomb of Light."

"The tomb of light?"

"A low-light-speed black hole created by the wake of a light-speed spacecraft. World No. [-] is such a black hole. Some events have occurred, making them think that the coordinates of their world have been exposed, so they can only do this."

"We are called Heiyu."

"Well, this name is more appropriate. In fact, people in the third world called it the light curtain, the curtain of the curtain, and later people outside called it the light tomb, and they regarded it as a tomb. But everyone has his own aspirations. For the people in World No. [-], it is a paradise of peace and happiness. I don’t know if they still see it that way. After the Tomb of Light is built, there will be no news from that world, but I think the people there should live a good life. , because for some people, safety is the foundation of a happy life."

Cheng Xin asked Guan Yifan when New World built the light-speed spaceship, and the answer he got was a century ago.From this point of view, Yun Tianming's information gave the humans of the solar system an advantage over the humans of the galaxy for nearly two centuries, even considering the time of pioneering the new world, it was at least a century earlier.

"He is a great person." When Cheng Xin talked about Yun Tianming, Guan Yifan said.

However, the civilization of the solar system did not seize this opportunity. 35 years, 35 years of life and death, were delayed, and it may be delayed by her.Thinking of this now, her heart no longer feels pain, only the numbness after death.

Guan Yifan said: "For human beings, traveling at the speed of light is a milestone. This can be regarded as the third enlightenment movement, the third Renaissance, because traveling at the speed of light has fundamentally changed people's thinking, and also changed civilization and culture. .”

"Yeah, the moment I entered the speed of light, I also changed. Thinking that I can cross time and space in my lifetime, reach the edge of the universe in space, and reach the end of the universe in time, those things that only stayed on the philosophical level before suddenly It became very realistic and concrete.”

"Yes, such as the end of the universe, the purpose of the universe, these things that used to be very philosophical and ethereal, now every layman has to think about it."

"Did anyone among you ever think about going to the end of the universe?" Cheng Xin asked.

"Of course, now, New World has sent out five ultimate spaceships."

"The ultimate spaceship?"

"Some people call it a doomsday spaceship. Those light-speed spaceships have no destination. They just turn on the curvature engine to the maximum power and accelerate crazily, infinitely close to the speed of light. The purpose is to use the effect of relativity to span time and reach the end of the universe. According to their calculations, within ten years it will be possible Spanning 500 billion years, they have now arrived, oh, of course in their frame of reference. Actually, there is no need to do this consciously, such as after the spacecraft accelerates to the speed of light, the curvature engine malfunctions irreparably, making the spacecraft Can't slow down, you might reach the end of the universe in your lifetime."

"Human beings in the solar system are very pitiful. Until the end, most people only lived in that small piece of time and space, just like those old people in the AD century who never left their mountain villages. The universe is still a mystery to them." Cheng Xin said.

Guan Yifan raised his head from the overweight seat and looked at Cheng Xin. Under the 3G overweight, this was a very strenuous movement, but he persisted for a while.

"I have no regrets, let me tell you, I really have no regrets. It's better not to know the truth of the universe."

"why?"

Guan Yifan raised his finger to point to the sea of ​​stars in the Milky Way, and then let his arm hit his body with a 3G weight.

"All of this is dark."

"Are you referring to the dark forest state?"

Guan Yifan shook his head, as if he was struggling under the overweight, "The dark forest state is the whole of our existence, but it is just a small thing for the universe. If the universe is a big battlefield—in fact it is—between the battlefields, Snipers shoot and kill people who are inadvertently exposed by the other party, such as signal soldiers, or gang leaders, etc. This is the state of the dark forest; it is a trivial matter for war, and you have not seen a real interstellar war. "

"Have you met?"

"I've seen a little bit, but more is just speculation... Do you really want to know? The more you know about this kind of thing, the less light you have in your heart."

"There's no light left in my heart, and I want to know."

Thus, more than six centuries after Luo Ji fell into the icy lake in the cold night, in front of the only remaining human beings on Earth, the veil of darkness in the universe was lifted again.

Guan Yifan asked: "Guess what is the most powerful weapon for a civilization with almost unlimited technical capabilities? Don't think from a technical point of view, but from a philosophical level."

Cheng Xin thought for a while, then shook her head struggling, "I don't know."

"Things you've been through can give you some hints."

What has she been through?She had just seen that in order to destroy a star system, ruthless attackers reduced the dimension of space there by one dimension.Spatial dimension, what is the spatial dimension?
"The laws of the universe," Cheng Xin said.

"You are very smart, it is the laws of the universe. The laws of the universe are the most terrible weapon, and of course the most effective means of defense. Whether in the Milky Way or the Andromeda Nebula, whether in the local galaxy group or the super galaxy group, in the real interstellar war , Those participating civilizations with god-like technical powers do not hesitate to use the laws of the universe as weapons of war. There are many laws that can be used as weapons, the most commonly used are the space dimension and the speed of light, and generally the reduced dimension is used to attack, reduce The speed of light is used for defense. Therefore, the dimensional attack received by the solar system is the top attack method. How should I put it, this is also the honor of the earth civilization. The use of dimensional attack is to look up to you. In this universe, it is not easy to be seen. .”

"I think of one thing to ask you: When will the fall of the space of the solar system to two dimensions stop?"

"Never stop."

Cheng Xin shivered, and raised her head with difficulty to stare at Guan Yifan.

"This scares you? Do you think that only the solar system in the Milky Way and the entire universe is falling to two dimensions? Hehe..."

Guan Yifan's sneer made Cheng Xin's heart twitch again, and she said, "If this is the case, what you said is not valid, at least the use of lowering the dimension of space as a weapon is not valid. In the long run, this is an attack of mutual destruction. Go down, and sooner or later the space where the party that launched the dimensional attack will fall to two dimensions!"

There was a long silence, until Cheng Xin called out, "Dr. Guan?"

"You are too kind." Guan Yifan said softly.

"I don't know……"

"There's an option that keeps the dimensional attackers from getting killed together, if you think about it."

After a long silence, Cheng Xin said, "I can't think of it."

"I know you can't think of it, because you are too kind. It's very simple: the attacker first transforms himself, transforming himself into a low-dimensional life, such as transforming a four-dimensional life into a three-dimensional life, and of course it can transform from a three-dimensional life into a two-dimensional one. When the entire civilization enters the low-dimensional, it launches a dimensional attack on the enemy, unscrupulous, and attacks on a super large scale without any scruples."

Cheng Xin fell into a long silence again.

"Did you remember something?" Guan Yifan asked.

Cheng Xin was indeed remembering.She remembered the conversation between the expedition team and the "Lord of the Rings" when the "Blue Space" and "Gravity" strayed into the fragments of the four-dimensional space more than 400 years ago. At that time, Guan Yifan was a member of the expedition team.

Is this four-dimensional space built by you?
You say you came from the sea, but did you build the sea?
So, is this four-dimensional space something like an ocean to you, or to your builders?

It's a puddle, the sea is dry.

Why are there so many spaceships, or graveyards, gathered in such a small space?

When the sea dries up, the fish will gather in the puddles, and the puddles will also dry up, and the fish will disappear.

Are all the fish here?

The fish that dried up the sea are absent.

Sorry, this is very confusing.

The fish that dried up the sea landed on land before the sea dried up, running from one dark forest to another.

"Is there such a price to be paid for the victory of the war?" Cheng Xin said, it was hard for her to imagine what it would be like to live in a space that was lowered by one dimension. Is it really possible for people who have lived in a three-dimensional world to live in a piece of thin paper without thickness?Of course, life in three-dimensional space is also unimaginable to people in the four-dimensional world.

The answer Cheng Xin got was very simple.

"It's better than dying." Guan Yifan said.

Ignoring Cheng Xin's shock, Guan Yifan continued: "The speed of light is also a regular weapon that is frequently used, but building a light tomb for yourself or the black domain you mentioned is not one of them. It's just a way for us weak bugs to save our lives. Gods Disdain this. In war, you can create low-light-speed black holes to seal the enemy inside; but they are more used for defense, as walls and traps. Some low-light-speed belts are so large that they traverse the entire spiral arm of the galaxy. In dense places, a large number of low-light-speed black holes merge into one, stretching tens of millions of light-years, that is the Great Wall of the Stars, no matter how powerful the fleet is, once trapped, it will never come out, this is an obstacle that is difficult to overcome."

"What will happen if this continues?" Cheng Xin asked.

"As a result of the dimensional attack, the proportion of the two-dimensional space in the universe will gradually increase, and will eventually exceed the three-dimensional space. One day, the third macroscopic dimension will completely disappear, and the universe will become two-dimensional. As for the speed of light attack and defense, it will make The areas of low light speed keep increasing, and these areas will finally be connected as a whole in the diffusion, and the different slow light speeds in them will be balanced to the same value, and this value is the new C value of the universe; at that time, the science in the infant age like us It will be considered that the speed of light in a vacuum of more than ten kilometers per second is an iron-like cosmological constant, just like our current 30 kilometers per second. Of course, these are just two examples, and there are other laws of the universe that are Used as weapons, but so far we don't know which ones. It is very likely that all laws can be weaponized. In a certain part of the universe, the laws used as weapons may even include... Of course, this is just a wild guess , It’s too mysterious, I don’t believe it either.”

"What is included?"

"The laws of mathematics."

Cheng Xin exhausted her imagination, but she still couldn't grasp this incredible scene, she couldn't even grasp a corner of it, "This is... too crazy!"

"Will the universe become a war ruin?" Cheng Xin asked, and quickly thought of a more accurate expression, "Or, will the laws of nature become a war ruin?"

"Probably already... Now, physics and cosmology in the new world are just doing one thing: trying to restore the original appearance of the laws of nature before the war. There is already a relatively clear theoretical model that describes what has not been changed by the war The universe. It is really a beautiful pastoral. That era, more than 100 billion years ago, is called the pastoral age of the universe. Of course, that kind of beauty can only be described by mathematics, and it is impossible for us to imagine the pastoral age of the universe. Universe, our brains don’t have enough dimensions.”

Cheng Xin recalled those conversations again:
Is this four-dimensional space built by you?
You say you came from the sea, but did you build the sea?
"You mean, the universe in the Pastoral Age was four-dimensional, and the speed of light in a vacuum was much higher then than it is now?"

"Of course not. The universe in the pastoral age was not four-dimensional, but ten-dimensional. The speed of light in a vacuum at that time was not much higher than it is now, but close to infinity. The light at that time was acting at a distance, and it could The inner world is transmitted from one end of the universe to the other... If you have been to the four-dimensional space, you will know how wonderful the ten-dimensional universe is.”

"My God, you mean..."

"I didn't say anything." Guan Yifan said, as if waking up suddenly, "We only saw a little bit of the truth, and the rest are speculations, so you can just take it as guesses, a piece of fiction we made up. Dark Myth."

But Cheng Xin was unmoved, and went straight along with his thoughts just now: "In the era of war after the pastoral era, one dimension after another was imprisoned from the macroscopic to the microscopic, and the speed of light slowed down step by step..."

"I said I didn't say anything, it's all speculation." Guan Yifan's voice gradually dropped, "But no one knows whether the truth is darker than speculation... One thing is certain: the universe is dying."

The acceleration of the spacecraft stopped, and everything was in weightlessness.Before this, the space and the sea of ​​stars in Cheng Xin's eyes became more and more blurry, more and more like a nightmare, only the 3G overweight brought some realism, she seemed to be hugged by a pair of powerful arms, this kind of hug made her somewhat Able to withstand the cold and fear of the dark myths of the universe; now the excess weight is gone and only nightmares remain.The Milky Way is like a large ice stain covering the blood, and the nearby star DX3906 is like a burning cremator on the abyss.

"Can you turn off the panorama display?" Cheng Xin said softly.

Guan Yifan turned off the display, and Cheng Xin returned from the vast space to the small eggshell-like cabin in an instant, where she regained a sense of security.

"I shouldn't have said that to you." Guan Yifan said, the remorse in his tone sounded very sincere.

"I'll find out sooner or later." Cheng Xin said, her voice still very soft.

"Again, it's all guesswork, there's no real scientific proof. Don't think too much, just pay attention to the life in front of you." Guan Yifan put his hand on Cheng Xin's, "Those things I said, even if they are true, They are all based on a time unit of billions of years. If you go to our world, that is also your world, where you can live your own life. Don’t take a large leap in time, as long as you limit your life to 10 Within ten thousand years, limit the scope of your life to one thousand light years, and those things have nothing to do with you. 10 years, one thousand light years, is it enough?"

"That's enough, thank you." Cheng Xin took Guan Yifan's hand.

Cheng Xin and Guan Yifan spent the rest of the voyage in the forced sleep of the sleeper.The voyage lasted four days, and when they woke up in the decelerating overweight, the gray star had already occupied most of the space in their field of vision.Gray Star is a small planet with a surface appearance similar to that of the moon, like a large bare stone ball.But there are no craters on the surface of Gray Star, and most of them are desolate plains. The "Hunter" is moored into the orbit of the gray star. Since there is no atmosphere, the orbit of the spacecraft can be kept very low.The spacecraft went to the coordinates provided by the surveillance satellites, where five unidentified aircraft landed and took off.Guan Yifan originally planned to take the shuttle to land there, and then inspect the traces left by the aircraft, but neither he nor Cheng Xin thought that the objects left by the mysterious visitor were so huge that they could be seen from space.

"What is that?" Cheng Xin pointed at the surface of Gray Star and exclaimed.

"Deadline." Guan Yifan said, he immediately recognized what Cheng Xin saw, "Be careful not to get too close to it!" He said to the AI.

The dead lines Guan Yifan mentioned are five black lines, one end of which is connected to the surface of the gray star, and the other end extends into space.According to visual inspection, the length of each wire is about [-] kilometers, which is already higher than the orbit of the spacecraft, like the five black hairs grown by Gray Star.

"what is that?"

"The trajectory driven by curvature is a super-powerful drive, and the speed of light in the trajectory is zero."

During the next lap of the spaceship, Guan Yifan and Cheng Xin entered the shuttle, left the spaceship and landed on the surface of the gray star.Due to the low orbit and no need to pass through the atmosphere, the descent process is rapid and smooth.The shuttle landed on the gray star land, about 3000 meters away from the dead line.

They jumped towards the dead line under the gravity of 0.2G.The plain of the gray star is covered with a thin layer of dust, and gravels of different sizes are distributed. Because there is no atmospheric scattering, the shadows and bright areas under the sun are clearly black and white.They quickly walked to a place more than 100 meters away from the dead line, Guan Yifan waved Cheng Xin to stop.The diameter of the dead lines reaches 30 meters. From this point of view, they should be called dead columns.

"This may be the darkest thing in the universe," Cheng Xin said.The dead line shows no detail other than the extreme blackness that marks the extent of the zero-light zone, where there should be no surface.Looking upwards, even against the pitch-black backdrop of space, the darker dead lines are still clearly visible.

"It is also the deadliest thing in the universe." Guan Yifan said, "Zero speed of light is death in the true sense, absolute death, [-]% death. In it, every elementary particle, every quark, is dead, there is no The slightest vibration. Even if there is no gravitational source inside the dead line, it is a black hole, a zero-gravity black hole, and it is impossible for anything to go in and come out."

Guan Yifan picked up a stone and threw it towards a dead line, the stone disappeared into the absolute blackness of the dead line.

"Can your light-speed spaceship produce dead lines?" Cheng Xin asked.

"Far from it."

"So you've seen this before?"

"I've seen it, I haven't seen much."

Cheng Xin looked up at these huge black pillars stretching towards the sky. They lifted up the starry sky, as if turning the universe into a palace of death.Is this the destination of all things?she thinks.

In the sky, Cheng Xin could see the end of the dead line, she pointed in that direction and asked, "Where does the spaceship enter the speed of light?"

"Yes, it looks like hundreds of kilometers. We have seen it shorter than this before. It is an instant to enter the speed of light."

"Is this the most advanced light-speed spacecraft?"

"Maybe, but this kind of practice is rare, and dead lines are usually made by zeroers."

"Return to zero?"

"It is also called a restarter. It may be a group of intelligent individuals, or it may be a civilization, or several civilizations. We don't know, but their existence has been confirmed. The zero-returner wants to restart the universe and return to the pastoral age."

"How?"

"Turn the clock past twelve o'clock. For example, in the space dimension, it is almost impossible to pull a universe that has fallen into a low-dimensional universe back to a high-dimensional one; but work hard in another direction, reduce the universe to zero-dimensional, and then continue to descend. Dimensions, it is possible to return to the original from the zero direction, and make the macroscopic dimension of the universe return to ten dimensions.”

"Zero-dimensional?! Have you seen zero-dimensional space?!"

"No, I've only seen two-dimensionalization, not even one-dimensionalization, but somewhere there must be a zero-returner doing it, and no one knows if it's successful. Relatively speaking, it's easy to reduce the speed of light to zero. Some, they also do more, trying to dial the speed of light to zero and reproduce the infinite speed of light."

"Is it possible, theoretically?"

"I don't know yet, maybe the theory of the zero-returner thinks it is possible. But in my opinion, it is impossible. For example, zero speed of light is a wall that cannot be passed. Zero speed of light is the absolute death of all existence, which means that there will be no more existence. Any movement. In this state, it is impossible for the subject to have any effect on the objective. How can it be possible to move the 'hour hand' forward? What the zero-returners do is more like a religion, a performance art."

Cheng Xin looked at the dead line, her fear became awe, "If it's a flight track, why didn't it spread?"

Guan Yifan grabbed Cheng Xin's arm nervously, "That's exactly what I want to say. We have to leave quickly, not to leave the gray star, but to leave this galaxy. It is very dangerous here. The state of the dead line is different from the general curvature trajectory , if there is no disturbance, it will keep like this, that is, it will keep the diameter of the curvature engine’s action surface, but when disturbance occurs, it will spread and spread rapidly; a dead line of this scale can spread to the size of a star system, and scholars put This is called a dead line rupture."

"The area it spreads to is zero speed of light?"

"No no, after the dead line diffuses, it is like an ordinary curvature track. The interior is no longer zero light speed. The wider the spread, the higher the interior light speed, but it is still a low light speed of more than ten kilometers per second. So, these After the dead line spreads, it is possible to turn this galaxy into a low-light-speed black hole, which is what you call a black field... let's go."

Cheng Xin and Guan Yifan turned around and jumped towards the shuttle.

"What disturbance are you talking about?" Cheng Xin asked, and looked back. On the plain behind them, the shadows of five dead lines stretched to the horizon.

"It's not very clear now. There are theories that other curvature tracks appearing nearby, and it has been proved that there is a certain induction between curvature tracks within a certain distance."

"Then, when the Halo accelerates, will it..."

"So, we need to use fusion propulsion to go away and then start the curvature drive. At least we have to leave—by your measure—forty astronomical units."

After the shuttle took off, Cheng Xin still stared intently at the disappearing dead line from the surveillance screen, and she said, "Return to Zero, let me see some bright colors."

Guan Yifan said: "The universe is rich and colorful, and there are all kinds of 'people' or worlds. There are idealists like zero returners, pacifists, philanthropists, and civilizations that only focus on art and beauty. But they are not the mainstream, and they cannot dominate the direction of the universe."

"Just like the human world."

"However, for the zeroers, their work will ultimately be done by the universe itself."

"You mean the end of the universe?"

"Yes."

"But as far as I know, the universe will continue to expand forever, becoming thinner and colder."

"That's your cosmology, but we overturned that conclusion. The amount of dark matter is underestimated, the universe will stop expanding, then collapse under its own gravity, and finally become a singularity and explode again, bringing everything back to zero. So you see, the ultimate winner is nature."

"Is the new universe ten-dimensional?"

"It's impossible to know, there are endless possibilities, it's a whole new universe, a whole new life."

The voyage back to Blue Star was as smooth as it was when they came. Cheng Xin and Guan Yifan spent most of the time in forced sleep.When they were awakened, the spacecraft had already parked in the orbit of the blue star.Looking at the blue and white world below, Cheng Xin actually felt like coming home.

At this time, Ai AA's call came from the communication channel, and Guan Yifan responded.

"This is the Hunter. What's the matter?"

AA's voice was urgent: "I called you several times, but only the spaceship answered. No matter what I say, it won't wake you up!"

"Didn't you say not to communicate casually? What happened?"

"Something has happened! Yun Tianming is here!"

The last sentence was like a thunderbolt, jolting Cheng Xin out of the remaining drowsiness, and even Guan Yifan froze in astonishment.

"What are you talking about?" Cheng Xin said softly.

"Yun Tianming is here! His spaceship landed more than three hours ago!"

"Oh—" Cheng Xin responded mechanically.

"He's still so young, as young as you!"

"Really?" Cheng Xin felt as if her voice was coming from far away.

"He also brought you a present!"

"He's already given me a gift, and we're in his gift."

"That's nothing, let me tell you, this gift is better, better, and bigger... He's out now, I'll find him to talk to you!"

Guan Yifan interjected and said: "No need, we will go down immediately, communication is dangerous, so I cut it off." After speaking, he cut off the communication.

They looked at each other for a long time, and finally both laughed. "Are we really awake?" Cheng Xin asked.

Even if it was a dream, Cheng Xin wanted to hang around for a while longer.She activated the panoramic display, and the starry sky no longer looked so dark and cold, but was full of clear beauty like the first sunshine after rain. Even the starlight carried the fragrance of spring buds, which was a feeling of rebirth.

"Get into the shuttle, we'll land as soon as possible." Guan Yifan said.

They entered the shuttle, and the ship began the shuttle's disengagement procedure.In the narrow cabin, Guan Yifan made the final inspection and test before re-entering the atmosphere in an interface window.

"How did he come so fast?" Cheng Xin said in a sleepy voice.

Guan Yifan had completely calmed down at this time, "This confirms our guess: the Trisolaran First Fleet has established a colony nearby, within a hundred light-years away from here. They must have received the signal from the 'Halo'." gravitational wave signal."

The shuttle separated from the spaceship, and the pyramid-shaped hull of the "Hunter" could be seen on the surveillance screen gradually receding.

"What gift can be bigger than a star system?" Guan Yifan asked Cheng Xin with a smile.

The excited Cheng Xin just shook her head.

The fusion engine of the shuttle starts to start, the heat dissipation ring on the outside glows red, the thrusters are warming up, the control screen shows that after 30 seconds, the deceleration will start, and the orbit of the shuttle will drop sharply until it enters the atmosphere of Blue Star.

Suddenly, Cheng Xin heard a sharp and strange sound, as if the shuttle was being cut open from end to end by a sharp knife, followed by a violent vibration, and then, she experienced a strange moment: the strange thing was that she dared not It must be a moment, this moment is both infinitely short and infinitely long, at this moment she has a sense of leap, feeling that she is outside of time.Later, Guan Yifan told her that she experienced a "time vacuum", and the length of that moment cannot be measured by time, because time does not exist at that moment.At the same time, she felt that she was collapsing, as if she was about to become a singularity. At this moment, the mass of her, Guan Yifan, and the shuttle became infinite, and then everything fell into darkness.At first, Cheng Xin thought it was her eyes that had a problem. She couldn't believe that the inside of the spacecraft could become so dark that she couldn't see her fingers.Cheng Xin called Guan Yifan, but there was a dead silence in the earphones of the spacesuit.

Guan Yifan groped in the dark and hugged Cheng Xin's head. She felt her face pressed against his face tightly. She didn't resist, but felt great comfort.But she soon discovered that Guan Yifan did this only to talk to her, because the communication system of the space suit was turned off, and the voices could be transmitted to each other only when the two helmet visors were pressed together.

"Don't be afraid, don't panic, listen to me! Don't move now!" Cheng Xin heard Guan Yifan's voice coming from behind the mask, and she knew he must be shouting loudly from the contact feeling, but the sound she heard was very small , like a whisper.She felt his other hand groping for something, and soon the cabin lit up.The light came from a cigarette-length strip in Guan Yifan's hand. Cheng Xin knew that it might be a chemiluminescent substance, and there was something similar in the emergency equipment of the "Hinghuan", which could emit cold light after being bent.

"Don't move, the space suit is out of oxygen supply, slow down your breathing, I'll pressurize the cabin right now! Don't be afraid, it will be soon!" Guan Yifan said, handing the light strip to Cheng Xin, and pulling the seat away. A storage cabinet on the side, from which he took out a metal bottle, like a small fire extinguisher, he twisted the mouth of the bottle, and a gust of white gas spewed out of the bottle immediately.

Cheng Xin began to feel short of breath. She knew that the control system of the space suit stopped working, and the oxygen supply stopped immediately. What she was breathing now was only a little bit of residual oxygen in the helmet.Her breathing became rapid, and the harder she inhaled, the faster she felt suffocated.She instinctively raised her hand to open the mask, but Guan Yifan grabbed her hand to stop her, and hugged her again, this time to comfort her.She felt as if he was holding her and floating up from the deep water, and in the cold light of the light strip, she saw his eyes, which seemed to tell her that he was about to reach the surface of the water.Cheng Xin also felt the rising air pressure in the spacesuit. Just when she was about to suffocate completely, Guan Yifan opened her mask and then opened his own, and the two breathed heavily.

After her breathing eased a bit, Cheng Xin noticed the metal bottle, and she particularly noticed a small gauge on the neck of the bottle, which was a barometer. Cheng Xin found that it was an old pointer barometer, and the pointer had now slid to the green. district.

Guan Yifan said: "The oxygen won't last long, it will get cold here soon, we have to change into space suits quickly." He got up and floated away from the seat, pulled out two metal boxes from the back of the cabin, and Opening one, Cheng Xin saw the spacesuit inside.Whether in the solar system or here, the current space suits are already very light. If you don’t wear a helmet and the interior is not pressurized, and remove the small life support box, it doesn’t look much different from ordinary clothes. The two sets of spacesuits I saw were very bulky, much like the spacesuits of the century AD.

White water vapor appeared in their breath, and after Cheng Xin took off her original spacesuit, she felt the bitter cold in the cabin.The bulky space suit was very difficult to put on, Guan Yifan helped Cheng Xin put it on, she felt like a child, in front of this man, she felt a long-lost sense of dependence.Before putting on the helmet, Guan Yifan carefully explained to Cheng Xin how to use this spacesuit, telling her where the oxygen supply switch, pressurization switch, temperature adjustment knob, communication switch, lighting switch, etc. are located.This space suit does not have any automatic devices, all its functions need to be done manually.

"There is no computer chip in it, and now, all computers, whether electronic or quantum, cannot be activated." Guan Yifan explained.

"why?"

"Because the current speed of light may only be a dozen kilometers per second."

Guan Yifan put the helmet on for Cheng Xin. At this moment, her body was almost frozen.Guan Yifan turned on the oxygen supply switch for her, and turned on the electric heating system at the same time. Cheng Xin felt that the space suit was gradually getting warmer.At this time, Guan Yifan started to change the spacesuit by himself. He put on the helmet very quickly. After putting on the helmet, it took a lot of trouble to connect the communication systems on the two spacesuits, but they were too cold to speak for a while. Come, I can only silently wait for my body to warm up.Under the gravity of 1G, it would be difficult to move while wearing this bulky spacesuit. Cheng Xin felt that it was more like a small house, the only place she lived in now.The light strip floating in the cabin had already dimmed, Guan Yifan turned on the light on his spacesuit.In the cramped cabin, Cheng Xin felt like they were miners trapped underground in ancient times.

"What happened?" Cheng Xin asked.

Guan Yifan floated up from the seat, and struggling to pull something on the bulkhead, a transparent porthole appeared—the internal baffle of the porthole used to be opened automatically, and it was very laborious to open it manually.Then, he also opened a porthole on the bulkhead on the other side.

Cheng Xin looked outside and found that the universe had completely changed.

She first saw two star clusters at opposite ends of space, with the front cluster glowing blue and the rear cluster glowing red.She had seen such a scene in the light-speed flight of the "Halo" before, but the two star clusters that appeared now were no longer stable, and their shapes changed wildly, like two flames in a strong wind.No stars popped out of the blue star cluster ahead, and fell across space into the red star cluster behind. Connecting the two poles of the universe are two light bands, which are located on both sides of space, and only one can be seen from a porthole. The wider band of light occupies half of the near space, and its two ends are not in direct contact with the blue-red star cluster, but form two pointed round heads at a distance.Cheng Xin could see that this broad band of light was actually a very flat ellipse, or an extremely elongated circle.There were color blocks of different sizes and shapes moving quickly across the broadband. Those color blocks mainly had three colors: blue, white, and light yellow—intuition told Cheng Xin that this light band was the blue star.The other band of light is thinner and brighter. On its surface, no details can be seen except for strong light. Unlike the blue star, the length of this band of light changes sharply periodically, and at the longest time it becomes a bright band connecting the blue and red poles. The line shrinks into a bright sphere for a short time, and the latter form reveals its original shape in the normal space-time, which is the star DX3906.

"We are orbiting the blue star at the speed of light, of course, at a low speed of light." Guan Yifan said.

The speed of the shuttle used to be higher than the speed of light at this time, but since it is impossible to exceed the speed of light, its speed fell to a low speed of light.

"The dead line spread?"

"Yes, spread throughout the galaxy, and we're stuck here."

"Is it because of the disturbance of Yun Tianming's spacecraft?"

"I don't know, it's possible, he doesn't know that there is a dead line in this galaxy."

Cheng Xin didn't continue to ask, she didn't want to ask what to do next, she knew that there was probably nothing to do.No computer can run at the speed of light more than ten kilometers per second. The AI ​​and control systems of all layers of the shuttle are dead. In this case, this space vehicle can't even turn on a small light inside. , it's just a metal pot without electricity and power. The "Hunter" spacecraft also became a dead ship.Before falling into the low speed of light, the shuttle has not started to decelerate and propel, and the spacecraft should be not far away, but even if it is close to it, it is impossible to get in, because there is no control system, and the hatches of the shuttle and the spacecraft cannot be opened.

Cheng Xin thought of Yun Tianming and Ai AA. They were on the ground, so they should be safe, but now they couldn't contact each other, and she couldn't even say a word to him.

At this moment, a floating object hit her mask lightly. It was the metal bottle, and Cheng Xin saw the pointer barometer on it again.She touched her space suit again, and the light of hope that had been extinguished shone like a firefly again.

"Are you prepared for this situation?" Cheng Xin asked softly.

"Yes, I'm ready." Guan Yifan's voice came from the earphone of Cheng Xin's spacesuit. This is an ancient analog signal communication, and the voice is somewhat distorted. The driving track situation, that situation is the same as now, low speed of light, everything stops... Next, we should activate the neurons."

"what?"

"Neuron computer, a computer that can operate at low light speed. Both the shuttle and the spaceship have two sets of control systems, one of which is neuron mode."

Cheng Xin was amazed that there was a computer that could run at such a low speed of light.

"The key is not the speed of light, but the system mode. The chemical signal transmission in the human brain is slower, only two or three meters per second, which is similar to the speed of human walking. The neuron computer is a fully parallel processing that simulates the brains of higher animals. The chips used They're all designed for low light speeds."

Guan Yifan opened a metal panel, and there was a sign on it, which was a complex interconnection of many dots, and each dot stretched out many tentacles like a small octopus.A small console emerges, with a flat-screen display on it, and a few switches and lights, things that disappeared at the end of the Crisis Era.Guan Yifan pressed a red switch, and the screen lit up. There was no graphical interface displayed, only a bunch of text prompts. Cheng Xin probably saw that it was the startup process of an operating system.

"Now the neuron parallel mode has not been established, and the operating system can only be loaded serially. You really can't imagine how slow the serial data communication is at the low speed of light. See, only a few hundred bytes per second , not even 1K."

"It takes a long time to start."

"Yes, but with the gradual establishment of the parallel mode, the loading speed will continue to increase, but it really takes a long time to complete the startup." Guan Yifan said, pointing to a line of prompts at the bottom of the screen.

68 hours and 43 minutes (tick seconds) remaining on the lead portion, and 297 hours and 52 minutes (tick seconds) remaining on the overall.

"Twelve days!" Cheng Xin said in surprise, "What about the spaceship?"

"There is a slow light speed detection device on the spacecraft, which can automatically start the neuron computer. It should have started by now, but the completion time is about the same as here."

Twelve days, and only after twelve days can the survival resources in the shuttle and spacecraft be used. During this period, they can only live with these two primitive space suits.If the power source in the spacesuit is a nuclear battery, it should be able to last this long, but there is definitely not enough oxygen.

"We have to hibernate." Guan Yifan said.

"Is there a hibernation device on the shuttle?" Cheng Xin knew it was meaningless as soon as he asked. The hibernation device is also intelligently controlled by the computer. Even if there is, it can't be used now.

Guan Yifan took out a small box from the storage cabinet where he took out the metal oxygen cylinder just now, and he opened the small box to show Cheng Xin the capsules inside. "This is a short-term hibernation drug. Unlike the previous ones, it does not require an extracorporeal circulation maintenance device. After hibernation, the breathing will be extremely slow, and the oxygen consumption will be very low. One pill can hibernate for about fifteen days."

Cheng Xin opened the mask and swallowed a hibernation capsule.Seeing that Guan Yifan also ate one, she looked out the porthole again.

The blue star, the broadband connecting the blue and red poles of the universe at the speed of light, flows faster on its surface, and the color blocks can no longer be distinguished.

"Can you see that there is a cycle in the graph above?" Guan Yifan asked, he didn't look anywhere, his eyes were half-closed and he restrained himself on the overweight seat.

"It's too fast, I can't see it."

"The eyes follow it."

Cheng Xin did as he said, and quickly followed the flowing broadband with her eyes. Those blue, white and yellow patches could be seen clearly for a moment, but soon blurred again. "Still can't tell," she said.

"Yeah, it's too fast. It might repeat hundreds of times per second." After Guan Yifan finished speaking, he sighed silently. Even though he tried his best not to let Cheng Xin notice his sadness, she could still see it. She knew the reason for his sadness. .

She knew that every cycle of the pattern flowing on the broadband meant that the shuttle orbited the blue star at the speed of light.At the low speed of light, the devilish law of special relativity is still valid, and in that frame of reference, time is passing by tens of millions of times like lightning, like blood flowing from Cheng Xin's heart.

At this moment, the sea has changed.

Cheng Xin silently looked away from the porthole and fixed herself on the seat.The porthole on the other side shines light that changes periodically. Outside, the sun of this world pulls into a bright line connecting the two poles of the universe, then shrinks into a ball of light, and then stretches out into a bright line, as if jumping to death crazily dance.

"Cheng Xin," Guan Yifan called softly, "Maybe when we wake up, we see an error message displayed on the screen."

Cheng Xin turned her head and smiled at him through the mask, "I'm not afraid."

"Of course I know that you are not afraid, I just want to talk to you. I know your experience as a sword holder, and I just want to say that you are not wrong. The human world chose you, that is, it chose to treat life and everything with love, Although it comes at a huge cost. You fulfill the aspirations of that world, you fulfill the values ​​that are there, you fulfill their choices, and you’re really not wrong.”

"Thank you." Cheng Xin said softly.

"I don't know your later experience, but I believe you are right. Love is right. It is impossible for one person to destroy a world. If this world is destroyed, it will be the common cause of all people, including the living and the dead. The result of hard work."

"Thank you." Cheng Xin said again, tears welling up in her eyes.

"As for what happens next, I'm also not afraid. As early as when I was on the 'Gravity', the starry sky made me feel scared and tired. I wanted to stop thinking about the universe, but I couldn't stop like taking drugs. .Now, you can stop."

"That's good, you know? The only thing I'm afraid of is that you will be afraid."

"Me too."

Hand in hand, they gradually lost consciousness and breath in the crazy dance of the sun.

[about 170 billion years after the beginning of time, our star]

The process of waking up was very long, and Cheng Xin's consciousness gradually recovered bit by bit. When her memory and vision recovered, the first thing she knew was that the neuron computer had successfully activated.The cabin was illuminated by soft light, the humming sounds from various equipment could be heard clearly, there was a warm feeling in the air, and the shuttle was revived.

But Cheng Xin soon discovered that the position of the light source in the cabin was obviously different from the original one, and it might be a backup lighting device specially designed for low light speed.There is also no information window in the air, and the low speed of light may not be able to drive such a holographic display.The human-machine interface of the neuron computer is the flat-panel display, which now displays a colorful graphical interface, much like the century AD.

Guan Yifan was floating in front of the screen, tapping the screen with his ungloved fingers to operate.Finding Cheng Xin woke up, he smiled at her, made an OK gesture, and handed her a bottle of water.

"Sixteen days." He looked at Cheng Xin and said.

When Cheng Xin took the water bottle, she realized that she wasn't wearing gloves either. The water bottle was hot.She then discovered that although she was still wearing the original spacesuit, the helmet had been removed, and the air pressure and temperature in the cabin were very comfortable.

Cheng Xin unbuckled the seat belt with her newly regained consciousness, floated to Guan Yifan's side, and watched the screen with him.They were all wearing space suits, but neither of them was wearing a helmet, and the space suits were packed tightly together.There are several windows open on the screen at the same time, and a large amount of data is scrolling inside, and various systems of the shuttle are being tested.Guan Yifan told Cheng Xin that he had already contacted the "Hunter", and the neuron computer there had also started normally.

Cheng Xin raised her head and saw that the two portholes were still open, so she floated over.In order for her to see clearly outside, Guan Yifan dimmed the lighting in the cabin.Now, there is a tacit understanding between them, like one person.

At first glance, the outer universe has not changed significantly. It is still the scene seen when the blue star orbits at a low speed of light. The blue and red star clusters are still changing shapes erratically at the two poles of the universe. The sun Still dancing wildly between straight lines and spheres, the surface of the blue star is still rapidly flowing with periodic patches of color.When quickly tracking the color blocks with her eyes, Cheng Xin noticed a change: in the colors of the color blocks, blue and white disappeared, replaced by purple.

"The detection of the engine system is basically normal. We can slow down and escape the speed of light at any time." Guan Yifan pointed to the screen and said.

"The fusion engine still works?" Cheng Xin asked.Before hibernation, she had been thinking about this question, but she didn't ask, because she knew that she would probably get a desperate answer, and she didn't want to make things difficult for Yifan.

"Of course it can't be used. The power of nuclear fusion at low light speed is too low. We need to activate the backup antimatter engine."

"Antimatter?! A container stored at a low speed of light..."

"No problem, the anti-matter engine is specially designed for the low-light speed environment. For such a long-range voyage, the aircraft is equipped with a low-light speed power system... Our world has done a lot of research on low-light speed technology, and the purpose is not to solve the problem of stray The problem of the curvature of the track, but in case one day has to hide in the tomb of light, or in the black domain."

Half an hour later, the shuttle and the "Hunter" spacecraft started their antimatter engines at the same time and began to slow down.Cheng Xin and Guan Yifan were pressed tightly on the seat by the overweight, and the porthole was already closed.The violent vibration appeared, then gradually subsided, and finally disappeared completely. The deceleration lasted only ten minutes, and then the engine stopped, and the weightlessness reappeared.

"We are out of the speed of light." Guan Yifan said, pressing a button on the bulkhead and opening two portholes at the same time.

Through the porthole, Cheng Xin saw that the blue and red star clusters had disappeared.She saw the sun, which was a normal sun, not significantly changed from what she had seen before.But when she saw the blue star from the porthole on the other side, she was surprised. The blue star had turned into a purple star. Except for the pale yellow ocean, the land was covered in purple, and the snow was white. completely gone.What shocked her most was the starry sky.

"What are those lines?!" Cheng Xin exclaimed in shock.

"It should be a star." Guan Yifan replied simply, as shocked as Cheng Xin.

The stars in space all became thin glowing lines.Cheng Xin seemed familiar with the linear stars. She had seen long-exposure photos of the starry sky many times. Due to the rotation of the earth, the stars on the photos became line segments, and their length and direction were the same.But now, the lines formed by the stars are of different lengths and directions. The longest bright lines almost run through one-third of the space. These bright lines intersect each other at various angles, making the starry sky look more confusing It's messed up a lot.

"It should be a star." Guan Yifan said again, "Starlight has to pass through two interfaces to get here. First, it passes through the interface between light speed and slow light speed, and then passes through the event horizon of the black hole. It becomes like this."

"We are in the black domain?"

"Yes, we are in the Tomb of Light."

The DX3906 galaxy has turned into a low-light-speed black hole, completely isolated from the rest of the universe, and the starry sky composed of numerous silver lines will always be an unattainable existence.

"Let's go down." Guan Yifan broke the long silence and said.

The shuttle slowed down again, causing the orbit to drop sharply, and entered the Blue Star's atmosphere amid violent vibrations, landing towards the world where Cheng Xin and Guan Yifan were destined to spend their lives.

In the surveillance screen, the purple continent occupies the entire field of vision, and it is now certain that purple is the color of plants.The blue-to-purple plants in Blue Star may be due to changes in the sun's light radiation. In order to adapt to the new light, they turned purple.

In fact, the very existence of the sun confuses Cheng Xin and Guan Yifan.According to the mass-energy equation, nuclear fusion at low light speed can only produce very little energy. Perhaps, the sun still maintains the normal light speed inside.

The landing coordinates set for the shuttle were the location where it last took off from Blue Star, and where the Halo spacecraft was located.When approaching the ground, only a dense purple forest can be seen at the landing site.Just as the shuttle was about to fly away in search of an open space to land, the flames from the thrusters made the big trees on the ground escape one after another, and the shuttle landed smoothly on a field vacated by the forest.

The screen shows that the air outside can be breathed. Compared with the previous landing, the oxygen content in the atmosphere has increased a lot, and the atmosphere is denser. The external pressure is 1.5 times that of the previous landing.

Cheng Xin and Guan Yifan stepped out of the shuttle and set foot on Blue Star again.Warm and humid air blows in, and the ground is covered with a layer of humus leaves, which are very soft.The open space is full of holes, which are left by the roots of the big tree that escaped just now.The purple trees now crowded round the clearing, their broad leaves swaying in the wind like a crowd of whispering giants around them; the clearing was entirely in shade.Such dense vegetation is already a different world from the last time I saw the blue star.

Cheng Xin didn't like purple, and always felt that it was a sickly and depressing color, which reminded her of the lips of a patient with insufficient oxygen supply to the heart.Now, she is surrounded by this overwhelming purple, and will spend the rest of her life in this purple world.

There was no "Xinghuan", no Yun Tianming's spaceship, and no trace of any human beings.

Guan Yifan and Cheng Xin inspected the surrounding terrain through the forest, and found that the terrain was completely different from their last landing site. They clearly remembered that there were continuous mountain peaks near the landing site, but now it was a flat woodland.They suspected that the landing coordinates were wrong, and returned to the shuttle to check, and found that this was indeed the landing site of the "Halo" last time.They searched the vicinity carefully again, but found no relics. This place is like a virgin land that has never been set foot by human beings, as if their last trip to the blue star happened on another planet in another time and space, which has nothing to do with this place. It doesn't matter.

Guan Yifan returned to the shuttle and contacted the "Hunter" spacecraft that was still operating in low-earth orbit.The neuron computer on the spacecraft is powerful, and the AI ​​it supports can directly communicate with each other. At low light speed, there is a time lag of more than ten seconds in dialogue and communication.Since leaving the speed of light with the shuttle, the "Hunter" has been conducting remote sensing searches of the blue star's surface in low orbit, and it has now completed a search of most of the planet's landmass, finding no trace of human beings, and no other signs of intelligent life.

Next, Cheng Xin and Guan Yifan could only start with one thing that terrified them deeply but had to do: determine the current era.There is a special method for dating at low light speeds. Some elements that do not decay in the world at normal light speeds will decay at different rates at low light speeds, so the duration of low light speeds can be accurately determined.As a scientific investigation aircraft, the shuttle has an instrument for measuring the decay of elements, but it is an independent device without a neuron computer control system, and only has an interface with the neuron host of the shuttle. Guan Yifan took a lot of trouble to make it The device can be used normally.They had the instrument sequentially measure ten rock samples taken from different areas so that the results could be compared.This process takes half an hour.

While waiting for the test results, Cheng Xin and Guan Yifan got out of the shuttle and waited in the open space.The sun shines in through the gaps in the forest.There are many strange little creatures flying by in the clearing, there are insects spinning and flying like helicopter propellers, and groups of transparent small balloons float in the air by buoyancy, changing brilliant iridescence when passing through the sun; but No winged creatures were seen.

"Maybe tens of thousands of years have passed." Cheng Xin murmured.

"Maybe longer than that." Guan Yifan looked into the depths of the forest and said, "However, now, tens of thousands of years, tens of thousands of years, what's the difference?"

Then they were all silent, clinging to each other and sitting on the gangway of the shuttle, feeling each other's heartbeat.

Half an hour later, they walked up the gangway to face the reality they had to face.The test data of ten samples are displayed on the screen of the console. Multiple elements have been detected. It is a complex table. The test results of all samples are extremely close. Below the table, the average result is concisely listed:
The average decay time of elements detected in samples 1-10 (error: 0.4%):
Interstellar time period: 6177906;

Earth year: 18903729
Cheng Xin counted the digits of the last number three times, then turned around silently and walked out of the shuttle, walked down the gangway, and stood in this purple world.A circle of tall purple trees surrounds her, a ray of sunlight casts small spots of light at her feet, the warm and humid wind blows her hair, and a small transparent balloon floats lightly over her head, 890 Thousands of years followed her behind.

Guan Yifan came to Cheng Xin's side, their eyes met and their souls fused together.

"Cheng Xin, we missed it." Guan Yifan said.

3906 million years after the formation of the low-speed black hole in the DX890 galaxy, and 170 billion years after the birth of the universe, a woman and a man hug each other tightly.

Cheng Xin fell on Guan Yifan's shoulder and wept bitterly. In her memory, this kind of bitter cry was only once when Yun Tianming's brain was separated from his body. That was... 18903729 years plus six centuries ago. Those six centuries are already negligible in this long geological time.But this time, her crying was not just for Yun Tianming, it was a kind of giving up, she finally saw clearly what kind of strong wind it was that made this dust of herself fly around; What a big river it is.She gave up completely, letting the wind blow through her body and the sun through her soul.

They sat on the soft humus leaves and continued to embrace each other silently, letting time go by.Spots of sunlight cast through the gaps in the leaves slipped past them.Sometimes, Cheng Xin asked herself: Has another 1000 million years passed?There is a strange rational body in her consciousness, quietly telling her that it is not impossible, there really is a world that spans thousands of years at will.Think about the dead line, if it spreads a little bit, the speed of light inside will change from zero to an extremely low value, such as the speed of continental drift, one centimeter in 1 years.In such a world, when you get up from your lover's arms and take a few steps, you will be separated from him by tens of thousands of years.

They missed it.

After an unknown amount of time, Guan Yifan asked softly, "What should we do?"

"I want to search again. Is there really no trace?"

"It's really gone. In 800 million years, everything will disappear. Time is the most ruthless thing."

"Carve words on stone."

Guan Yifan raised his head and looked at Cheng Xin in bewilderment.

"Ai AA knows how to carve words on stones." Cheng Xin seemed to be talking to herself.

"I really do not understand……"

Cheng Xin didn't explain further, she hugged Guan Yifan's shoulders and asked, "Can you let the 'Hunter' conduct a deep remote sensing survey here to see what's under the ground?"

"What will it be?"

"Words, see if there are any words."

Guan Yifan shook his head with a smile, "I understand your behavior, but..."

"For long-term preservation, those words should be very large."

Guan Yifan nodded in agreement, obviously just to satisfy Cheng Xin's wish.He and Cheng Xin got up and went back to the shuttle. During such a short journey, they still cuddled tightly, as if they were worried that they would be separated by time if they were separated.Guan Yifan issued an instruction to the "Hunter" spacecraft in orbit to let it conduct in-depth remote sensing detection of the formation in a radius of 3000 meters around this coordinate point. The detection depth is between five meters and ten meters, focusing on identifying characters and other meaningful symbol.

The "Hunter" flew over the sky 15 minutes later, sent back the detection results 10 minutes later, and found nothing.

Guan Yifan once again ordered the spacecraft to detect in the depth range of 20 meters to [-] meters in the stratum.This took more than an hour, most of the time waiting for the spacecraft to fly overhead again, and nothing was found.At this depth there is no soil, only dense rock.

Guan Yifan increased the detection depth to between 30 and 30 meters. He said to Cheng Xin, "This is the last time. The depth of stratum remote sensing detection generally cannot exceed [-] meters."

They waited for the spacecraft to circle the blue star again.At this time, the sun was setting, and the sky was filled with gorgeous sunset glow, which gilded the purple forest.

This time the detection made some discoveries, and the screen in the shuttle displayed the image sent back by the spacecraft.After clear processing, several white writings can be vaguely recognized in the black rock formation: "men", "pass", "one", "sheng", "you", "small", "zai", "face", "pass" and "go". "" and "的", white means that the characters are indented. The size of the characters is one meter square, divided into four lines, and the position is 23 meters to 28 meters below their feet, on a plane inclined at an angle of [-] degrees.

The spacecraft AI explained that remote sensing detection can only achieve such an accuracy, further active detection is required, and the shuttle needs to send detection waves to the corresponding position in the formation.

Cheng Xin and Guan Yifan waited excitedly. As it got dark, the surrounding forest became a circle of silhouettes.In the sky, bright threads of stars began to appear, some of which were longer, like silver hairs scattered on black velvet.

An hour later, the remote sensing image they received showed four lines of writing spanning 890 million years:

we lived a happy life

we give you a little
escape the collapse in

go new
The spacecraft AI invoked the geological expert system to interpret the detection results, from which it can be known that these large characters were originally engraved on a large mountain rock, which is a sedimentary rock, and the area of ​​​​the engraved side is about 130 square meters.During the tens of millions of years of long-term crustal changes, the mountain where this mountain rock is located sank, and this huge rock also sank to its current position in the stratum.There are more than four lines of characters carved on the rock surface, but the bottom of the rock was broken during the sinking process, those characters were lost, and a corner of the existing inscriptions was also broken, resulting in the incompleteness of the last three lines of the existing characters.

Cheng Xin and Guan Yifan embraced together again. They both shed tears of joy for Ai AA and Yun Tianming, happily feeling the happiness of those two people 18 centuries ago. In this happiness, their desperate hearts became It was very peaceful.

"What's their life like here?" Cheng Xin asked with tears in her eyes.

"Everything is possible." Guan Yifan raised his head and said.

"Do they have children?"

"Everything is possible, even, believe it or not, they once established civilization on this planet."

Cheng Xin knew that this was indeed possible, but even if that civilization lasted for 1000 million years, the next 890 million years would be enough to erase all traces of it.

Time is indeed the most ruthless thing.

At this time, a strange thing interrupted their emotion, it was a rectangle drawn by shimmering thin lines, it was as tall as a person, floating in the open space, it seemed to be pulled out in the real picture with a mouse a box of .It moves slowly while floating, but the range of movement is very small, and it turns back before it floats too far.It is likely that this thing has always been there, but its frame is very thin, and the light it emits is not strong, so it cannot be seen in daylight.Regardless of whether it is a field or an entity, this must be an intelligent creation.The bright lines that outline the rectangles seem to have some sort of mystical connection to the linear stars in the sky.

"Could this be the little...little gift they gave us?" Cheng Xin stared at the box and said.

"Improbable, this thing can be stored for more than 800 million years?"

But this time he was wrong, the thing was indeed stored for 890 million years, and could be stored until the end of the universe if need be, because it was outside of time.Originally it was placed next to the inscribed rock, with a solid metal frame, but the metal turned to dust after only 50 years.And this thing is always new, it is not afraid of time, because its own time has not yet begun.It was originally at a depth of 30 meters in the formation, still beside the rock, but it detected the people on the ground, so it rose to the ground, and it did not interact with the formation, just like a phantom.On the ground, it confirmed that the two men were what it had been waiting for.

"I think it looks like a door." Cheng Xin said softly.

Guan Yifan picked up a twig and threw it towards the rectangle. The twig passed through the space surrounded by it and fell to the ground on the other side.They also saw a group of small fluorescent balloons floating over, several of them passed through the inside of the rectangle and floated away unharmed, and one of them even passed through the glowing frame.

Guan Yifan touched the frame line with his hand, and his fingers passed through the frame line, but he didn't feel anything.Inadvertently, his hand reached into the space enclosed by the rectangle.This was indeed an unintentional action, because he felt that there must be nothing in this section of space, but Cheng Xin let out a cry, which was rare for her calm.Guan Yifan hastily withdrew his hand, his hand and arm were intact.

"Just now your hand didn't go through!" Cheng Xin pointed to the other side of the rectangle.

Guan Yifan tried again, and the hand and a section of the forearm disappeared after passing through the plane of the box, and did not appear on the other side.From the other side, Cheng Xin saw the section of his forearm, like a mirror, the bones and tendons were clearly visible.He withdrew his hand and picked up another twig to try, and the twig went through the square.Immediately afterwards, two propeller-shaped flying insects also passed through the box.

"This is indeed a door, a door with intelligent recognition function." Guan Yifan said.

"It lets you in."

"Maybe you can too."

Cheng Xin tried it carefully, and her arm could also enter the "door". When Guan Yifan saw the section of her forearm from the other side, he seemed to know this scene before.

"You wait for me, I'll go over and have a look." Guan Yifan said.

"Let's go together." Cheng Xin said firmly.

"No, you wait for me here."

Cheng Xin pulled Guan Yifan's shoulders to make him face her, looked into his eyes and said, "Do you want us to be separated by 800 million years?!"

Guan Yifan stared at Cheng Xin for a long time, and finally nodded, "Can we bring some things there?"

Ten minutes later, they walked through the door holding hands.

【Beyond Time, Our Universe】

The unopened darkness of chaos.

Cheng Xin and Guan Yifan entered the time vacuum again.This is very similar to when they travel through the low speed of light in the shuttle, where the time flow rate is zero, or there is no time.They lose their sense of time and replace it with a sense of transcendence, of transcending everything beyond everything.

The darkness disappears and time begins.

There is no corresponding vocabulary in human language to express the moment when time begins. It is wrong to say that time begins after they enter. "Later" is a concept of time. There is no time here, so there is no sequence.The time they enter "behind" can be shorter than a billionth of a second or longer than a billionth of a year.

The sun came on, very slowly, at first revealing only the shape of its own disk, before unveiling the veil of the world with sunlight, like a piece of music that gradually flowed from barely audible tones.A blue circle appeared around the sun, and slowly expanded to form a blue sky.Under the blue sky, a field gradually appeared, or it was just a corner of the field, there was a piece of unplanted land with black soil.Beside the land were a few fine white houses, and a few trees, the only thing that gave an exotic color, with broad leaves and strange shapes.Under the gradually brightening sun, this secluded countryside is like an open embrace to them.

"Someone!" Guan Yifan said, pointing to the distance.

On the horizon, there are the backs of two people. It can be seen that they are a man and a woman. The man has just lowered his arms.

"That's us." Cheng Xin said.

Farther in front of the two figures, white houses and trees can also be seen, exactly as here, the ground cannot be seen because of the angle, but it is to be expected that there is also a black field like here.That is to say, at the end of this world, there is another copy of this world, which may also be a reflection.

Replicas and reflections of the world exist around them. When they look to both sides, they both see the same idyllic world. They are also in that world, but they can only see their backs. When they turn their heads, the people in the replica world also Turn your head at the same time.They looked back and were surprised to find that there was the same pastoral world behind them, but they were looking from another direction, and they were far away in that pastoral world.

The entrance to this world is without a trace.

They walked along a path paved with stones, and at the same time they walked in all the replica worlds around them.A creek cut off the path, and there was no bridge over the creek, but they could jump over it with a lift of their legs, and that's when they realized that there was a normal gravity of 1G.They walked past the trees and came to the white house, where they found the door shut and the windows shaded by blue curtains.It's all brand new and spotless.They are also brand new indeed, and time is just beginning to flow here.In front of the house are some simple and primitive agricultural tools, including shovels, rakes, baskets and buckets, etc. Although the shapes are a little different, their uses can be clearly seen.The most eye-catching thing is a row of metal pillars standing next to the agricultural tools. They are all one person tall, and their smooth shells shine in the sun. There are four metal parts on each of them, which can be seen as folded limbs. These metal pillars may be closing robots.

They decided to familiarize themselves with the surrounding environment before entering these houses, so they continued to walk forward, and soon came to the edge of this small world.Now, they are facing the duplicated world in front of them. At first, they thought it was a reflection, although they could not explain its direction, but halfway through, they denied this idea, because the duplicated world was too real, not like in a mirror .Sure enough, they took a step forward and entered the duplication world without hindrance. Looking around, Cheng Xin felt a trace of fear.

Everything returned to the state when they first entered: they were in a pastoral that was exactly the same as before, with duplicate worlds of this pastoral in front and on both sides, and they also existed in these duplicate worlds.Looking back, in the field they just stepped out of, they are looking back at the farthest side of the field.

Cheng Xin let out a long breath when he heard Guan Yifan, "Okay, don't go anymore, you will never finish." He pointed to the sky and the earth, "There are obstacles in these two directions, otherwise you can see the same world."

"You know what this is?"

"Have you ever heard of the man Charles Michner?"

"No."

"He was a physicist in the 1000st century AD. He was the first person to imagine this kind of thing. The world we live in is actually very simple. It is a regular cube, and the side length I estimate is about [-] meters. You can imagine it as A room has four walls, plus a ceiling and a floor. But the strange thing about this room is that the ceiling is the floor, and of the four walls, the opposite two walls are actually one wall, so it really only has two walls. If You walk from one wall to the opposite wall, and when you get to the opposite wall, you're immediately back in front of the wall you started from. The same goes for the ceiling and the floor. So, it's a fully enclosed world , go back to the starting point when we go to the end. As for the images around us, they are also very simple, just because the light that reaches the end of the world returns to the starting point. We are still in the world just now, returning from the end to the starting point , there is only this one world, and the rest are reflections.”

"Then, this seems to be..."

"This is it!" Guan Yifan made an all-encompassing gesture, and said with emotion, "Yun Tianming once gave you a star, and now he gave you another universe. Cheng Xin, this is a universe. Although it is small, it is real. is a universe."

While Cheng Xin was looking at this small universe excitedly, Guan Yifan sat quietly on the ridge of the field, grabbed a handful of black soil, and watched the soil flow down his fingers, feeling a little depressed, "He is the most powerful man, he can treat the stars and the universe as A gift for someone he loves, but, Cheng Xin, I can't give you anything."

Cheng Xin also sat down, leaned on his shoulder and said with a smile, "But you are the only man in the universe, so you don't need to give me anything."

Guan Yifan still felt a little inferior, but what made him feel relieved was that no one in the universe could compete with him.

The feeling that there were only the two of them in this universe was quickly shattered.There was a soft knock at the door, and a white figure came out of a house and came towards them.This is a small world, and a person can be seen clearly from any distance. They saw that the person who came was a woman in a Japanese kimono. The gorgeous kimono dotted with small red flowers looked like moving flower clusters. Brings spring.

"Sophon!" Cheng Xin exclaimed in shock.

"I know her, the robot controlled by Sophon." Guan Yifan said.

They got up and walked to Tomoko, and the two met under a big tree.Cheng Xin was sure again that she was Sophon, her unreally beautiful appearance hadn't changed at all.

Sophon bowed deeply to Cheng Xin and Guan Yifan, stood up and said to Cheng Xin with a smile, "I said before, the universe is big, life is bigger, we really meet again."

"I really didn't expect it. It's so good to meet you, really!" Cheng Xin said with emotion. Sophon brought her back to the past. Now, any memories of the past are from 800 million years ago, but That's not accurate either, since they're already in another time.

Sophon bowed again, "Welcome to universe 647, I am the manager of this universe."

"The manager of the universe?" Guan Yifan looked at Sophon in surprise and said, "This is a great name, especially for a cosmology researcher like me, it sounds like..."

"Hehe, no," Tomoko smiled and waved his hands, "You are the real masters of No. 647, and you have the absolute right to decide everything here. I'm just serving you."

Sophon made an inviting gesture, and Cheng Xin and Guan Yifan followed her along the field ridge until they entered an elegant living room in a white house.The decoration style of the living room is Chinese style, with a few elegant calligraphy and paintings hanging on the wall. Cheng Xin paid special attention to see if there were any cultural relics brought out by the "Halo" from Pluto, but she didn't seem to have seen them.After taking a seat beside an antique wooden desk, Tomoko poured tea for them, this time without the tedious procedures of the tea ceremony.The tea leaves are like Longjing, standing up one by one at the bottom of the cup, forming a small green forest, exuding a burst of fragrance.

All this seemed like a dream to Cheng Xin and Guan Yifan.

Sophon said: "This universe is a gift, it was given to you two by Mr. Yun Tianming."

"I think it's for Cheng Xin." Guan Yifan said.

"No, the recipient must include you. Your authority was added to the later identification system, otherwise it would be impossible for you to enter. Mr. Yun Tianming hopes that you can escape the doomsday of our big universe in this small universe, which is the big collapse , into the new macrocosm after the new big bang. He wants you to see the idyllic age of the new universe. Now, we are in an independent timeline, and the time of the macrocosm is passing fast, and you will definitely be able to wait for it in your lifetime According to more specific estimates, the collapse of the large universe will reach the state of singularity within ten years."

"If a new creation explosion happens, how can we know?" Guan Yifan asked.

"What we can know, we can detect the state of the large universe through the supermembrane."

Sophon's words made Cheng Xin think of the words Yun Tianming and Ai AA carved on the rock, but Guan Yifan thought more, and he noticed a word Sophon mentioned: pastoral era.The use of this word to describe the peaceful times in the universe is the language of the galactic humans.There are two possibilities here: one is a coincidence, Trisolaris also just chose this word; the second possibility is very frightening—Three-solaris has detected the existence of humans in the Milky Way, and Yun Tianming rushed to the Blue Star It can be seen that the world of Trisolaris First Fleet is very close to the world of humans in the Milky Way.Now, the Trisolaran civilization has developed enough to be able to build a small universe, which is a huge threat to the human race in the galaxy.

But he immediately laughed out loud.

"What are you laughing at?" Cheng Xin asked strangely.

"Laugh at me for being ridiculous."

It's really ridiculous, even before entering the small universe, it has been 890 million years since he left the second world of human beings in the Milky Way. Now, the big universe he came from may have passed hundreds of millions of years, and he is worried about the ancients.

"Have you met Yun Tianming?" Cheng Xin asked.

Sophon shook his head lightly, "No, never."

"What about AA?"

"The last time I saw her was on Earth, and I never saw her again."

"Then how did you get here?"

"Universe 647 is a custom-made product. I will be here after it is completed. I am essentially just a data body, which can be copied in many copies."

"But did you know that Yun Tianming brought this universe to Blue Star?"

"I don't know what the blue star is. If it is a planet, he can't bring No. 647 there, because No. 647 itself is an independent universe, not inside the big universe. He can only bring the entrance of No. 647. get there."

"Why don't Yun Tianming and Ai AA come here?" Guan Yifan asked.This was what Cheng Xin wanted to know the most. The reason why she didn't ask was because she was afraid of getting a sad answer.

Sophon shook his head again, "I don't know. The identification system has always had Yun Tianming's authority."

"Anyone else?"

"No, it's just the three of you so far."

After a long silence, Cheng Xin said softly to Guan Yifan: "AA is a person who pays much attention to life in this world, and she will not be interested in the new universe tens of billions of years from now."

"I'm interested." Guan Yifan said, "I really want to see what the new universe looks like, especially when it has not been tampered and distorted by life and civilization, it must embody the highest harmony and beauty."

Cheng Xin said: "I also want to go to the new universe. The singularity and the big bang will erase all memories of this universe. I want to bring part of human memory to the new universe."

Sophon nodded solemnly to Cheng Xin, "This is a great cause, and someone is already doing it, but you are the first human in the solar system to do it."

"Your goals in life are always higher than mine." Guan Yifan whispered in Cheng Xin's ear, and Cheng Xin couldn't tell whether he was joking or serious.

Sophon stood up and said, "Then, your new life in Universe 647 has begun, let's go out and have a look."

As soon as they went out, Cheng Xin and Guan Yifan saw a scene of spring plowing. Those pillar-shaped robots were working in the fields. Sowing seeds in the field.The way they do farm work is very primitive. There is no wide rake that can be pulled, but a small rake that is held in the hand to level the ground a little bit; there is no seeder, the robot holds a bag of seeds in one hand, and bury the seeds in the ground with the other. .The whole scene has a simple color, here, the robot is even closer to nature than the farmer.

Zhizi introduced: "The food stored here is only enough for you to eat for two years, and you will have to live on farming in the future. The seeds sown now are all descendants of the seeds that Cheng Xin brought to Yun Tianming, and of course they have all been improved. .”

Guan Yifan looked at the black field, a little confused, "I think it's more reasonable to use cultivation tanks for soilless cultivation here."

Cheng Xin said: "People who come out of the earth have a kind of obsession with the land. I remember that in "Gone with the Wind", Scarlett's father said to her: Son, there is nothing in this world worth your life and blood. , except land."

Guan Yifan said: "Human beings in the solar system have shed the last drop of blood for their land, or in other words, there are only two drops of you and AA left. But what's the use, why don't they disappear without a trace? Now the big universe may pass away For hundreds of millions of years, do you really think anyone still remembers them? You are obsessed with the land and your homeland, and you are no longer children, but you still dare not travel far. This is the root cause of your demise. I am telling the truth, and I am not afraid of offending you."

Looking at the excited Guan Yifan, Cheng Xin smiled slightly and said, "You didn't offend me. What you said was the truth, and we knew it, but we couldn't do it. You may not be able to do it either. Don't forget, your 'Gravity' Humans become captives before they become galactic humans."

"That's true..." Guan Yifan hesitated, "In space, I never felt that I was a qualified man."

According to the standards of space, there are not many qualified men, and Cheng Xin will not like such a man.She thought of a qualified man, and his voice was still in her ears: Go forward, go forward!Go ahead by any means!

"Don't think about the past, now, everything is a new beginning." Tomoko said in a sweet voice.

A year in Universe 647 has passed.

The wheat in the field had been harvested for two seasons. Cheng Xin and Guan Yifan watched twice as the emerald green wheat seedlings slowly turned into golden waves of wheat, and the vegetable field next to them was always filled with green.

This small manor has a complete set of daily necessities, all of which have no trademarks and are obviously made in the Trisolaran world, but in appearance they are exactly the same as human products, without any exotic features.

Sometimes Cheng Xin and Guan Yifan went to the fields to do farm work with the robots, and sometimes they took a walk in the small universe.When you take a walk, you only need to keep going. As long as you don't pay attention to the footprints you left last time, you will feel like you are passing through an endless small world.

But they spend more time in front of the computer.A terminal window can be activated anywhere in the small universe, but they don't know where the host computer in this world is.There are a large amount of written and image data of the human beings on Earth in the computer, most of which are from before the broadcast era, obviously the information of the human world collected by Trisolaris, covering all fields of science and humanities; but more information is in Trisolarans , the quantity is huge and vast, and this is also the part they are most interested in.

They couldn't find the software to translate the three-body characters into human characters in the computer, so they started to learn the three-body characters, and Sophon became their teacher.But they soon discovered that it was extremely difficult, because the three-body script is a kind of ideographic script, which is different from human phonetic script, has nothing to do with language, and directly expresses meaning.Humans also appeared ideographic characters in ancient times. For example, some pictographs were ideographic, but they disappeared later, and human reading habits have completely become the habit of phonetic representation.However, they found that this difficulty only existed at the beginning, and it became easier as it went on.After two difficult months, their progress gradually picked up.Compared with phonograms, the biggest advantage of ideograms is the reading speed, which is at least ten times faster than phonograms.

Cheng Xin and Guan Yifan began to stumble through the literature on San Ti Wen.Their original purpose was twofold. One was to understand how Trisolaran recorded their history with Earth civilization, and the other was to know how this small universe was built—for the latter, they knew how to truly understand it from a professional perspective. It's unlikely, but at least you should know what's going on from the perspective of popular science.Sophon said that to achieve these two goals, they still need a year to further master the three-body script, and another year to read it.

The basic principle of building a small universe is indeed hard for them to imagine, and even some of the lower-level mysteries have not been understood for a long time.For example, in the space of one cubic kilometer, how is the ecological cycle established?what is the sunWhere does its energy come from?The most puzzling thing is: as a completely closed system, where does the heat in the small universe go?
Of course, what they are most concerned about is: Can the small universe communicate with the big universe?Sophon told them that it is absolutely impossible for the small universe to transmit information to the large universe, but it is possible to receive the information broadcast from the large universe.She said that all the universes are empty bubbles on a supermembrane (this involves the most basic theoretical picture in three-body physics and cosmology, and she cannot further explain this), and the large universe has enough energy to store information in spread on the supermembrane.But this is very difficult and requires an unimaginably huge amount of energy. If the big universe does this, it may need to turn the mass equivalent to a galaxy into pure energy.In fact, the monitoring system in universe 647 often receives information from other large universes on the supermembrane, some of which are naturally generated, and some are undecipherable intelligence information, but they have never received information from the large universe they came from.

Time passed day by day, like the water in that stream, calm and smooth.

Cheng Xin began to write a memoir, describing the history she knew, which she called "The Past Beyond Time".

Sometimes, they also envision life in new universes.Sophon told them that according to the theory of cosmology, the new universe must be higher than four-dimensional macroscopically, and it may even be higher than ten-dimensional.When a new universe is born, universe 647 can automatically establish an exit in it and detect the surrounding environment.If the new universe is higher than the fourth dimension, the exit of the small universe can move across the space until a suitable living environment is found; at the same time, it can also communicate with immigrants from other small universes in the Trisolaran world, and of course, it may also be connected with the immigrants from the Milky Way.In the new universe, the immigrants from the old universe almost belong to the same race, and they should be able to build a world together.Sophon especially emphasized that in the high-dimensional universe, there is a factor that greatly increases the probability of survival: among the many dimensions, there may be more than one dimension that belongs to time.

"Multidimensional time?" Cheng Xin couldn't understand what this concept meant for a moment.

"Even if time is only two-dimensional, it will be flat instead of straight. There are countless directions, which means that we can make countless choices at the same time." Guan Yifan explained.

"One of the choices is always right," Sophon said.

One night after the wheat field ripened for the second time, Cheng Xin woke up and found that Guan Yifan had gone out.She got up and went outside, and saw that the sun had turned into a bright moon, and the small world was immersed in the watery moonlight.She saw Guan Yifan, who was sitting by the stream, and she saw the melancholy in his back under the moonlight.

In this real two-person world, both of them are very sensitive to each other's mental state, and Cheng Xin has already discovered that Guan Yifan has something on his mind.In fact, he had been in a very sunny state most of the time before, until a few days ago he told Cheng Xin that if they could really live peacefully in the new universe, maybe their children could rebuild the human race.But later, he seemed to have discovered something suddenly. He often meditated for a long time alone, and sometimes he was still calculating something in the terminal window.

Cheng Xin sat down beside Guan Yifan, and he gently held her in his arms.The small world in the moonlight is very quiet, only the sound of water in the stream.The moon is shining on a field of ripe wheat, which will be harvested tomorrow.

"The quality is lost." Guan Yifan said.

Cheng Xin didn't say anything, she just looked at the moonlight dancing in the stream, she knew he would explain.

Guan Yifan went on to say: "I have been looking at the cosmology of the three-body system recently, and I just saw a piece of evidence for the beauty of universe mathematics: the design of the universe in terms of mass is extremely delicate, and the three-body people have proved that the total mass of the universe is just equal to Make the universe collapse, no more, no less, as long as the total mass is reduced a little, the universe will change from closed to open, and it will continue to expand forever."

"But the quality is losing." Cheng Xin said, she immediately realized the meaning of his last few words.

"Yes, the mass is losing. There are hundreds of small universes created by Trisolaris alone. How many other civilizations in the universe have created to avoid the big collapse or for other purposes? These small universes are taking away mass in the large universe."

"We should ask Tomoko."

"I asked, and she said that as of the completion of the construction of universe 647, according to the state of the universe observed by Trisolaran, no effect of mass loss has been found. The universe is closed and will definitely collapse."

"What about after No. 647 is completed?"

"Of course she doesn't know anymore. She said that in the cosmic civilization, there is a group of intelligent civilizations, which are very similar to those who return to zero. The big universe... But she doesn't know much about it. Well, stop thinking about it, we are not God."

"But we've long since had to think what God thinks, haven't we?"

They sat by the stream until the moon became the sun.

On the third day after the wheat harvest, the harvested wheat has been threshed and put into the warehouse.Cheng Xin and Guan Yifan stood on the ground, watching the robots plow the land and prepare for the next season's sowing.Now the warehouse is full of grain, and there is no place to put the wheat again.In the past, they would have heatedly discussed what to plant next season, but now, Cheng Xin and Guan Yifan are too preoccupied and don't care about these things anymore.They were in the room throughout the harvest and fight, discussing possible futures.As the two discover that every choice they make in their personal lives ultimately involves the fate of the universe, and sometimes the fate of multiple universes, they feel truly like God.This kind of grandeur made them breathless, so they went outside together.

They saw Tomoko walking quickly along the field ridge.Sophon never interferes with their lives, only showing up when they need it.But this time, her gait was different from before, very hurried, without the usual elegance, and the nervous expression on her face had never appeared before.

"We have received the supermembrane broadcast of the big universe!" Sophon said, and then called up a terminal window and made it very large. In order for them to see the contents of the window, she also dimmed the brightness of the sun.

There are countless lines of symbols scrolling quickly in the window, which are displayed by the dot matrix graphics sent by the super-membrane broadcast. Those symbols are strangely shaped and unrecognizable.Cheng Xin and Guan Yifan also noticed that each line of symbols was not of the same type, and they rolled by, like the surface of a swift river with messy ripples.

"The broadcast has been going on for 5 minutes, and it's still going on!" Tomoko said, pointing to the window, "Actually, the broadcast information is very short, and it lasted so long because of the use of different languages. Now tens of thousands of languages ​​have appeared, oh, to There are a hundred thousand kinds!"

"Is this broadcast to all small universes?" Cheng Xin asked.

"It must be, who else could it be? Using such a large amount of energy should be important information."

"Is there a three-body and earth language?"

"No."

Cheng Xin and Guan Yifan soon understood that this was the life and death book of a cosmic civilization.

Now, tens of billions of years may have passed in the big universe, no matter what the content of the broadcast information is, if the language of a civilization can be listed in the broadcast information, there are only two possibilities: this civilization still exists; or, this civilization has existed before , and survived for quite a long time, its culture left a permanent imprint on the universe.

A great river of symbols flows through the information window, and 20 languages ​​have been broadcast, 30, 40... 100 million languages, and the number is still increasing.

Trisomic language and Earth language still haven't appeared.

"It's nothing, we know we've lived, we've lived." Cheng Xin said, she and Guan Yifan cuddled tightly.

"Three-Body Problem!" Sophon suddenly shouted, pointing to the display window with one finger. At this time, the language types of the broadcast had increased to about 130 million, and there was a message in Three-Body Text in the window. It was impossible for Cheng Xin and Guan Yifan to read it. Clear, but Sophon can see clearly.

"Earth!" Sophon called again just a few seconds later.

When the language types of the broadcast information reached 150 million, the broadcast ended.

The scrolling display in the information window disappeared, and only two messages written in Trisolaran and Earth language were displayed statically.Cheng Xin and Guan Yifan didn't understand the content of the message, tears blurred their eyes.

On the last judgment day of the universe, two people and a robot from the two civilizations of the Earth and the Trisolaran embraced excitedly.

They know that the evolution of language and writing is very fast. If the two civilizations have existed for a long time, or even still exist now, their writing must be completely different from what is displayed now, but for people in the small universe to understand, Can only be displayed in ancient script.Compared with the total number of civilizations that have ever survived in the big universe, 150 million is a rather small number.

In the long night of the Orion spiral arm of the Milky Way, two meteors of civilization passed by, and the universe remembered their light.

After Cheng Xin and Guan Yifan calmed down, they read the content of the message carefully. The content written in the two languages ​​was the same, very short:
Return movement statement: The total mass of our universe is reduced below a critical value, the universe will change from closed to open, the universe will die in eternal expansion, and all life and memory will die.Please return the mass you took and send only the memory to the new universe.

Cheng Xin and Guan Yifan turned their eyes away from the return movement statement and looked at each other.From each other's eyes, they saw the dark prospect of the big universe.In the eternal expansion, all the galaxies will recede away from each other, until they recede beyond their respective line of sight. At that time, from any point in the universe, it will be dark in all directions.The stars will be extinguished one after another, the solid matter will disintegrate into thin nebulae, cold and darkness will rule everything, the universe will become an empty tomb, all civilizations and all memories will be buried forever in this endless tomb , everything dies forever.

In order to avoid this future, the only way is to return a large number of substances in the small universe produced by different civilizations to the big universe, but if this is done, people in the small universe will not be able to survive, and people in the small universe can only return to the big universe. This is the return movement.

The eyes of the two had exchanged everything and made the final decision, but Cheng Xin still said what she wanted to say:

"I want to go back, but if you want to stay here, I will stay with you too." She said to Guan Yifan.

Guan Yifan shook his head slowly, "I study a large universe with a diameter of 160 billion light-years, and I don't want to spend my whole life in this universe with a width of only 1000 meters. Let's go back."

"I don't suggest you do this." Sophon said, "We can't accurately measure the speed of time in the big universe, but we can be sure that at least tens of billions of years have passed in the big universe since you entered here from the blue star. Blue The stars have long since disappeared, and the sun that Yun Tianming gave you has long since gone out, we don't even know what kind of environment the big universe is like, and we don't even know if that universe is still three-dimensional."

"Isn't the door of the small universe able to move at the speed of light? Can it find a living environment?" Guan Yifan asked.

"If you insist, I'll look for it. However, I still think that staying here is the best option. There are two possible futures for staying in the small universe: If the return movement is successful, the large universe collapses into a singularity and dies." When a new big bang occurs, you can go to the new universe; if the return movement fails and the big universe dies, you can still spend your life here, and this small universe is not bad.”

"If everyone in the small universe thinks this way, then the big universe must be dead," Cheng Xin said.

Sophon looked at Cheng Xin speechlessly. Considering the speed of her thinking, this period of time might be as long as several centuries.It's hard to imagine that software algorithms can produce such complex gazes and expressions. Obviously, Sophon's AI software has retrieved all the memory data since he met Cheng Xin. The data has a span of nearly 2000 million years, and all the memories are Condensed in her eyes, sadness, admiration, surprise, blame, regret...all kinds of complex emotions are mixed together.

"You're still living with responsibility," Sophon said to Cheng Xin.

"Once Upon a Time Beyond Time" (excerpt)
ladder of responsibility

My whole life is climbing a ladder of responsibility.

When I was young, my responsibility was to study hard, be a good boy, and not let my parents down.

In middle school and university in the future, my responsibility is still to study hard, make myself a capable and outstanding person, and not let the society down.

Since my Ph.D., my responsibilities have become concrete. I want to make my own contribution to the advancement of launch vehicles. I want to create more powerful and more reliable rockets that can send very few people and materials to Earth orbit. .

After entering PIA, my responsibility became to send a probe into space a light-year away to meet the invading Trisolaran fleet.This distance is tens of billions of times the flight distance of the launch vehicle I participated in the development of before.

Then, I got a star, and in the new era, it brought me a responsibility that was unimaginable before, and I became the sword bearer of the dark forest menace.Looking back now, it is an exaggeration to say that I controlled the fate of mankind at that time, but I did control the historical trends of the two civilizations.

Then the responsibilities became complicated, and I wanted to put humans on the wings of light-speed flight, but I had to do the opposite: stop the wars that resulted.

I don't know how much I had to do with those catastrophes and the final destruction of the solar system, that can never be proven, but it certainly did, with my responsibility.

Now, I will ascend to the pinnacle of responsibility and be responsible for the fate of the universe.Of course, it is not just the two of us who are responsible for this, but we have a share of this responsibility. Such a responsibility was absolutely unimaginable before.

I want to say to those who believe in the existence of God, I am not chosen by him; I also want to say to the materialists, I am not the one who made history.I am just an ordinary person. Unfortunately, I have not been able to walk the life path of an ordinary person. My experience is actually a journey of civilization.

We now know that the course of every civilization is like this: awakening from a small cradle world, staggering out, flying up, faster and faster, farther and farther, and finally merged with the destiny of the universe.

For intelligent civilizations, they always end up being as big as their own minds.

Through the control system of universe 647, Sophon manipulates the gate of the small universe in the large universe, and the gate moves quickly in the large universe, looking for a world suitable for survival.The communication between the gate and the small universe can transmit very limited information. It cannot transmit images, but can only send back the evaluation result of the environment. This is a number between negative ten and ten, indicating the survival level of the environment, and only the level is greater than zero. environment in which human beings can live.

The door made tens of thousands of jumps and moves in the big universe. This process took three months, and only once detected a third-level environment. Sophon had to admit that this was the best result.

"The third-level environment is very harsh and dangerous!" Sophon said to Cheng Xin and Guan Yifan.

"We're not afraid, let's go there." Cheng Xin said firmly, and Guan Yifan nodded to her.

The door appeared in Universe 647. It is the same as what Cheng Xin and Guan Yifan saw on the blue star. It is also a rectangle drawn by glowing straight lines, but it is much larger than the one on the blue star. This may be for matter. Ease of transfer.When the door first appeared, it was not connected to the larger universe, and any matter could pass through it to the other side.When the sophon resets the parameters of the gate, the matter passing through the gate disappears, and they will appear in the grand universe.

Then, universe 647 began to return matter to the big universe.

According to Sophon, the small universe itself has no mass, and its mass comes from the matter brought from the large universe.Among the hundreds of small universes created by Trisolaris, No. 647 belongs to the smallest category. It took away about 50 tons of matter from the large universe, equivalent to the carrying capacity of a large oil tanker in the AD century. It is indeed insignificant on a cosmic scale.

Material handling begins with the soil.Since the second harvest, the field has not been sown again. The robots used the small carts for agricultural work to load the wet soil. After that, the soil disappeared.The soil was moved very quickly. Three days later, there was no grain of soil left in the small universe, and the few trees around the house were also brought into the door.

After the soil disappeared, a piece of metal ground appeared in the small universe.The ground is made up of smooth metal plates, reflecting the sun like a mirror.The robot removed the metal panels from one side of the ground and pushed them through the door piece by piece.

Under the opened ground on one side of the small world, a small spaceship was revealed.This spaceship is more than ten meters long, but it condenses the most advanced technology of the Trisolaran world.It is designed according to the ergonomics of human beings on the earth. It can take three crew members. It is equipped with two power systems of nuclear fusion and curvature drive. It has a mini ecological cycle system and hibernation device suitable for human beings. It can Land and take off directly on planets.Perhaps for the convenience of passing through the door of the small universe, its shape is slender and streamlined.This spacecraft was originally supposed to be used by the people in universe 647 when they entered the new universe. It can last for a long time before finding a suitable living environment in the new universe; now, they will take it back to the big universe.

The metal floor continued to be lifted, revealing the machinery and equipment underneath. This was the first time Cheng Xin and Guan Yifan saw something with the characteristics of the Three-Body Problem in the small universe.Just like what Cheng Xin had seen before, the design concept of these things was completely different from that of human beings. At first glance, they could not be seen as machines at all, like a bunch of grotesque sculptures or some kind of naturally formed geological structures.Robots began dismantling the machines, sending their parts through the door piece by piece.

Cheng Xin and Sophon were busy in the same room, they didn't let Guan Yifan go and watch, saying that they were doing a woman's thing, and they would give him a surprise in the end.

When a certain machine under the ground was turned off, the gravity in the small universe disappeared, and those white houses were suspended in the air.

In zero gravity, the robot dismantles the sky, a large film that reveals the blue sky and white clouds.At this time, the last ground was also removed.

Because the water body lost its restraint and evaporated in large quantities, the small universe was filled with clouds and mist, and the sun shone dimly behind the clouds, creating a brilliant rainbow across the universe.The water in the small world forms large and small liquid balls in weightlessness, refracts and reflects sunlight crystal clear, and floats around the rainbow.

With the dismantling of the machine and the shutdown of the ecological maintenance system, Cheng Xin and Guan Yifan put on space suits.

Sophon modified the passage parameters of the door again, allowing gas to pass through for the first time.There was a low rumbling sound in the small universe, which was made when the air rushed into the door.Below the rainbow, white clouds formed a great whirlpool near the door, like a typhoon on Earth seen from space.Then, the vortex turned into a tornado, and the sound it made also turned into a scream. The floating water balls were sucked into the tornado one after another, torn apart and disappeared through the door.Countless small objects floating in the air were also swallowed by the tornado.Large objects such as the sun, houses, and spaceships floated toward the door, but they were quickly held in the air by robots with thrusters.

As the air gradually thins, the rainbow disappears, the clouds become thinner, and the space becomes more and more transparent. The space of the small universe appears, which is the same as the space of the large universe, dark and deep, but without stars.Only three large objects remained floating in space: the sun, a house and spaceship, and a dozen robots in weightlessness.In Cheng Xin's eyes, this simple world resembled a naive painting she drew when she was a child.Cheng Xin and Guan Yifan activated the propellers on their space suits to fly deep into space in weightlessness. They reached the edge of the universe at the farthest of 1000 meters, and returned to the other side of the universe in an instant.The images of those objects can be seen in space, and there are infinitely many images in each direction, like the scenes in two mirrors placed opposite each other, a long row extending to infinity.

The last house was quickly demolished. This was Tomoko's oriental-style living room. The calligraphy, paintings, tea table and house fragments were sent in by the robot.

The sun finally went out, it was a metal sphere, the luminous half was transparent.Three robots pushed it all the way through the door.From now on, the small universe can only be illuminated by lights, and the space that has become a vacuum cools down quickly, and the remaining water and air are frozen into pieces of ice crystals, shining in the lights.

Under Sophon's command, all the robots lined up and filed into the door.

Now, in the space of the small universe, there is only a slender spaceship and three people floating beside it.

Sophon is holding a metal box, which is what they want to leave in the small universe, a drift bottle to be sent to the new universe.Its main body is a microcomputer, and the quantum memory of the computer stores all the information of the host computer in the small universe, which is almost the entire memory of the Trisolarans and the civilization of the earth.When the new universe is born, the metal box will receive a signal from the door, and then use its own small thruster to pass through the door and enter the new universe.It will float in the high-dimensional space of the new universe, waiting for the day to be picked up and interpreted.At the same time, it will use the neutrino beam to continuously broadcast the information stored by itself, if there are neutrinos in the new universe.

Cheng Xin and Guan Yifan believed that other small universes, those that responded to the appeal of the return movement, were doing the same thing.If a new universe is born, it will contain many bottles from the old universe.It can be believed that a considerable part of the information stored in the memory of the drifting bottle may reach such a level: it records all the memories and consciousness of each individual in that civilization, as well as all the biological details of each individual, so that all the people in the new universe A civilization can restore that civilization based on this information.

"Can I keep another five kilograms?" Cheng Xin asked.She was on the other side of the spaceship, wearing a space suit, holding a glowing transparent sphere in her hand, about half a meter in diameter, with several water spheres floating inside, some with a few small fish swimming inside, and some with growth covered with green algae; and two floating miniature landmasses covered with tender green grass.The light emanated from the top of the sphere, where mounted a small luminary, the sun of the small world.This is a fully enclosed ecological sphere, the result of more than ten days of work by Cheng Xin and Sophon. As long as the little sun inside the sphere can still shine, this small ecological system can survive.As long as it stays here, universe 647 is not a lifeless dark world.

"Of course, the big universe won't stop collapsing just because of the five kilograms." Guan Yifan said, he still has an unspoken idea: Maybe the big universe will really change from closed to open because of the mass difference of one atom.The ingenuity of nature sometimes exceeds imagination. For example, the birth of life requires the precise cooperation of various cosmic parameters with a precision of one billionth of a billionth.But Cheng Xin can still keep her ecological ball, because in the countless small universes created by countless civilizations, there must be a considerable part of them that do not respond to the call for returning to the movement. Therefore, the mass of the big universe that was eventually taken away was at least several hundred million tons. It could even be hundreds of billions of billions of tons.

I hope the big universe can ignore this error.

Cheng Xin and Guan Yifan entered the spaceship, and Sophon finally entered.She has long since stopped wearing that gorgeous kimono. Now she is wearing a camouflage uniform, and she is once again a light and capable warrior. Behind the back of the samurai sword.

"Don't worry, I'm here, and you are here!" Sophon said to the two human friends.

The fusion engine started, the thrusters emitted a faint blue light, and the spacecraft slowly passed through the gate of the universe.

Only the drift bottle and the eco-ball are left in the small universe.The drifting bottle is hidden in the darkness. In the 1000-meter-square universe, only the little sun in the ecosphere emits a little light.In this small world of life, several clear water polo float quietly in a zero-gravity environment. A small fish jumps out of one water polo, jumps into another water polo, and swims lightly through the green between algae.In the grass on a small piece of land, a drop of dew broke away from a blade of grass, swirled and floated up, refracting a ray of crystal sunlight into space.