Chu Tianle was quite surprised when he learned the news, but the matter had come to this point, and it was useless to say more. He sighed and reluctantly agreed. Ji Renrui also notified another "half of the party" Cao'er. After hearing this, Cao'er shook her head and said:

"This Jewish woman...... I don't have an opinion, and I believe my mom won't have an opinion. Make her wish come true. ”

This was a few days ago. When the "Tianma" learned the news, Yu Leshui was silent for a while, and said:

"It's supposed to be my husband's company, but it's just ...... Thank you Professor Elaina for me, and thank her for accompanying Tianle through life. ”

For the next few days, Yule Shui has been a little sullen. She was silent alone, and the past flowed back like a tide. At the age of twenty-five, she decided to stay in the mountains to accompany a disabled person who had recently died, a decision that was made mostly out of the passion of youth, on impulse, but she never regretted it. She and Tianle have a proud life, and both of them have given all their love to each other and the world. It's just that Tianle (and her platonic lover Ji Renrui) are advancing too aggressively and quickly on the path of reason, and she can't catch up. In any case, she would not agree to turn people into heads that absorb nutrients through a few pipes, or into ghosts that wander away from their bodies in electronic networks. Tianle said that the separation of mind and body is an inevitable step in human progress, and Yu Leshui did not want to argue with her husband on this point, but she did not allow this prospect to be realized in herself.

Therefore, she is reluctant to go to the spaceship to accompany her husband in a skull state, let alone abandon her body to accompany him like Ms. Elaina. However, thinking about becoming a passerby with her husband from now on, my heart still hurts like a knife. After all, the husband's "alienation" is to be a sober goose whistle, based on respectable motives......

At this time, Ji Jichang came over and said that the "little bee" had been connected to the mother ship, and asked her to take the "little bee" to the "goose whistle" to see off her husband.

"No, put on a spacesuit for me, I'd like to go to the hollow ball first." Yu Leshui said.

Emma dressed her in an extravehicular spacesuit with propulsion, and "Little Bee" carried her to the end of the crossbar of the "Goose Whistle". She flew out and towards the orb. Below, the vast Pacific Ocean is a pleasant blue; Above is a dark starry sky, and bright stars are as dense as grains of sand. The black sphere hangs from a long, cream-white crossbar, making it look very fragile. At this time, she saw the airtight door of the "Goose Whistle" open, and another spacewalker flew out, it was Ji Renrui. The intercom of the two has been connected, and Yu Leshui said worriedly:

"Brother Ji, your body ......"

"Don't worry, I'm almost recovered. Either way, I have to say goodbye 'face to face' with Tianle. ”

The two flew over with each other, and when they approached the sphere, Ji Renrui stopped first, so that Yu and Chu had a secret space to talk (the actual intercom was connected). Yu Leshui leaned in and touched the sphere through the gloves of the space suit. To protect the brain inside the ball, the ball is completely sealed. The sphere is equipped with a camera, and the external field of vision is converted into an electronic signal and then sent to Chu Tianle's field of vision, which is sent to the observation screen of the "Wild Goose Whistle". The same goes for sound conversion systems. Chu Tianle's semi-synthetic voice sounded in the intercom, and the quality of the voice was very high, very similar to Tianle's voice when he was young:

"Leshui, my love, I have seen your charming face and felt your affectionate touch—through electronic receptors, of course." Tianle smiled and said, "Let me tell you, although I was imprisoned in the heavy ball, I feel much more free since I abandoned that inferior body." I felt like I could travel through the nebula, travel through time. So don't be upset. I will always be watching you from heaven. ”

Yu Leshui sighed bitterly, "It is said that I should accompany you." ”

Chu Tianle said solemnly: "Don't think like this. Everyone has the right to live as they wish, and that is happiness. I've found my happiness, so you don't have to feel guilty at all. ”

"You don't have to persuade me, I'm not sad."

"I'm going to entrust you with one thing. Remember? I once said that I wanted to live to be 100 years old, and then I started to write a memoir called "A Hundred Years of Collecting Shellfish". It's no longer a problem to live for a hundred years now - now that I've abandoned my sick body, and sub-light motion will have a time delay effect - it's just a little inconvenient to 'get your hands dirty', haha. You can write it for me, and every time you finish writing a chapter, you will send it to me and Cao'er on the radio waves. ”

"Okay."

"Now you get in, the UN representative is waiting for you."

"I'll go and say goodbye to Miss Elaine."

As soon as she started the thruster and left, Ji Renrui leaned over, "Tianle, my good brother." ”

"Ren Rui, my good big brother."

"Tianle, I just want to say one sentence: I don't regret resigning from the government forty-two years ago and knowing you and your wife."

Tianle said: "Brother Renrui, although the responsibility is not mine, I always feel that I should apologize to you." You have begun a glorious era, but I have forcibly stopped it. ”

"That's fate. The article is hateful, and the charm is gratifying. When the moon is full, it is lost, and when the water is full, it overflows. God was not pleased with the building of the Tower of Babel by his people. However, the hardware and software of the new era are still there, and if the intellectual collapse does not occur - no, this may be basically zero, that is, if human intelligence can recover, it will still be easy to re-enter the space age. ”

"I hope so. In your words: walk up and find your way! ”

"Yes, let's walk up and find the way!"

"And, no matter what, - live!"

"Yes, alive!"

The two laughed "opposite each other", and their hearts danced with desolate passion. Ji Renrui said:

"Tianle, I have a plan for you. You are gone, our juniors are gone, leaving only Leshui, me, and Miao Qi. We want to move to the He family in the mountains, and it is convenient for them to gossip. ”

"That's good, you two have to worry about it, take care of Leshui for me."

"Take care of each other. Maybe Leshui will take care of us a little more. ”

The two reluctantly said goodbye.

As she spoke, Yu Leshui had already floated along the crossbar to the other end two kilometers away, and now, she was facing another woman across the two-meter-thick ball wall. Elaina Says:

"Hello, President Fish. Can I call you sister? ”

"Of course. Hello, Sister Elaina. ”

"I'll give you a little bit of information. Mr. Chu's body has been cremated, and he was cremated at the crematorium in the mountains, and he said that he didn't want you to see the injuries. My body was also cremated together, and I didn't want to put my head back in order to completely cut off my retreat. What you may not know is that the ex vivo surgery of the head that I developed can already be performed in both directions. ”

"Thank you for being with him, please take the trouble to take care of him."

"Of course. However, now I can only take care of him mentally, but when it comes to spiritual care, he should take care of me more. You know, in the spiritual realm, I've always looked up to him. ”

Yu Leshui was a little worried in her heart, she always felt that Elaina's decision was impulsive from a Westerner. Her actions are admirable, but will she be able to persevere to the end of her long and lonely life of captivity? Of course, Yu Leshui didn't let this worry be exposed, but just said goodbye to Elaine cordially.

Ji Renrui had already entered the spaceship, and Yu Leshui then flew into the airtight door of the "Yan Whistle" and took off his space suit. In the spacecraft hall, several heavyweight officials were waiting for her, they were: UN Secretary-General Croswell, UN Security Council Rotating President Huesh, UN SCAC Representative General Debirov, China's ** representative, Lin Bingzhang, the previous director of He Guoji's office, and ** representatives of other countries. Also present were: Ji Renrui, former president of the Friends of Music Engineering Institute, and Ms. Liu Su, the current president of the Friends of Music Foundation, Lowell, and Cheng Cheng, the current president of the Friends of Music Academy of Sciences. They were accompanied by Xi Mingzhe, captain of the "Yan Whistle," and Chu Cao, a navigator. Everyone shook hands and hugged her in turn, and Secretary-General Croswell said:

"Let's start now."

Huysh began to speak. The speech was broadcast live to the world:

My fellow human beings,

"After years of discussion, the current session of the United Nations General Assembly has unanimously adopted a resolution on the implementation of the 'Sleeping Beauty Project'. The full text of the resolution will be released to the world at a later date, and I will only touch on the main points of the Sleeping Beauty Project. The Goose Whistle spacecraft is about to begin a 174-year wormhole flight until the isolated wave of devastation that has reduced human intelligence is over and the universe returns to its primitive state of gentle expansion. During this period, Mr. Chu Tianle, as the human goose whistle, will stay at the junction of the wormhole and the mother universe, observing the changes of the earth at all times. At the same time, the countries of the earth have made careful preparations and set up self-destruction procedures for all facilities that may affect human security during the period of intellectual collapse, such as virus laboratories, genetic laboratories, nuclear power plants, reservoirs and dams, airplanes, rockets, chemical plants, and so on. Once the Goose Sentry confirms that human intelligence has fallen below a critical point, a command from him will initiate the process of self-destruction of said facilities throughout the world. At that time, human civilization will sleep for a while until the end of the vacuum and the recovery of human intelligence. As for the weapons of States, it has been decided that they will be destroyed in advance. ”

"The 'Sleeping Beauty' program has thorough security measures. In order to prevent Yan Whistle from going insane during his long-term solitary life, his self-destruction order will be countersigned by Mr. Xi Mingzhe, the captain of the spacecraft, and executed by Ms. Chu Cao, who each has independent veto power over Mr. Chu's orders. The psychological states of Xi Mingzhe and Chu Cao have undergone the strictest appraisal and are the best candidates to carry out this order. In addition, the self-destruct command contained a simple key, which would have been enough to solve the key if the human scientist had the intelligence of the average college student at that time, thus reversely aborting the command. ”

"As we all know, after mankind learned of the catastrophe 42 years ago, Mr. Chu Tianle made the most outstanding contribution in the process of human self-rescue. Now he voluntarily abandoned his body and imprisoned his head in a sphere to serve as a goose whistle for humans. In this regard, on behalf of the United Nations and on behalf of all humankind, I would like to express my most sincere gratitude to him. In view of Ms. Elaina's voluntary renunciation of her body to accompany Mr. Chu, we also extend our sincerest gratitude to this righteous lady. ”

"Now, on behalf of the United Nations General Assembly, I will hand over the self-destruction of human civilization, that is, the fate of mankind, to our Mr. Yan Whistle Chu."

"May the gods of mankind bless mankind."

As soon as the words fell, the two staff members brought up a gold plate with a mobile hard disk on it, and the self-destruct instructions contained in it could be copied directly into Chu Tianle's brain. Huesh turned to Yu Leshui and Ji Renrui and said:

"Now I invite the other two heroes of the catastrophic era, Ms. Yu Leshui and Mr. Ji Renrui of the 'Friends of Music' organization, to insert the disk into the computer with their own hands."

The two staff members handed the gold plate to Yu and Ji, and the two took off the disk, plugged it into the computer, and handed another key to the captain. Chu Tianle accepted the self-destruct order and said calmly:

"Thank you for believing in me, I will do my best. Now I'm going to verify the instructions. ”

He whispered the self-destruct command in his head. As he recited, a red switch appeared on the computer screen, covering it with two switch locks. At the end of the recitation, the first switch lock opened. The captain typed another key on the computer, and the second switch was turned on. Huysh Says:

"The order passed. Now, as long as the executor Chu Cao presses the fingerprint switch with his index finger, the self-destruct command will be sent to Earth. ”

Cao'er pressed the fingerprint switch with her index finger, and the screen displayed:

"The self-destruct procedure will be launched in thirty minutes. To abort, press the switch three times within thirty minutes. ”

Cao'er pressed the switch three times and exited the program.

At the end of the verification, the guests said goodbye to the crew members who were about to depart, said goodbye to Chu Tianle and Elaina, and finally said goodbye to Chu Cao and his mother. Twenty-four-year-old grass hugged her mother, and hot tears fell on her mother's shoulder. She said emotionally:

"Goodbye Mom! I'll take care of Daddy, don't worry. ”

Yu Leshui endured the sadness, patted her daughter's back, and comforted: "This is not the final farewell, I have to send you a mile." ”

The "Goose Whistle" set sail. The other guests returned to Earth in the "Little Bee", and only the Pegasus remained. Ji Renrui's body has basically recovered, and he and Miao Qi have stayed on the "Tianma" to send another ride for their old friend of forty years. The structure of the "Goose Whistle" is a completely new design, but in order to rush the time, it did not go through an industrial test flight, but took the first part of the journey as the test flight stage. To be on the safe side, the Pegasus was to follow it for a while until it was confirmed. In this wave of development and development, in order to rush to the greatest extent, all stages (including test flights) are arranged interlocking.

After the whimsical experience of the previous paragraph, Yu Leshui now painfully feels that the "Goose Whistle" is too pitiful, and its flight is like a dance with chains. Because, in order to keep pace with the two heavy balls (which are in non-native space and must obey Newtonian mechanics and relativity), the "Goose Whistle" can only accelerate slowly in a "uniform acceleration state", and the acceleration is set at 10 g, which is to make the two people in the heavy ball (the two heads) as comfortable as possible (the members in the wormhole have no acceleration). However, this "uniform acceleration" is only an intuitive metaphor, in principle, the "Goose Whistle" is a gradually accelerating intermittent vertical jump to drive the continuous uniform acceleration motion of two heavy balls, and the difference between the two movements is absorbed by the flexible member.

Although the acceleration is only 10 g, it is not the same as the chemically powered spacecraft of the past. Twelve days later, the "Wild Goose Whistle" had reached a speed of 100,000 kilometers per second and a flight mileage of 53 billion kilometers. It will accelerate to half the speed of light and then fly at a constant speed. Due to the planetary aspect, there was only close contact with Saturn during this flight, and the huge oblate spherical planet, covered in golden horizontal stripes, with its beautiful rings and a dozen moons, walked calmly past the porthole of the Pegasus. The rest of the time, outside the porthole, there was just an empty and lonely space, and the sky was embedded with an unchanging star map.

The "Wild Goose Whistle" is specially designed for low-speed working conditions, and at a low speed of 100,000 kilometers per hour, it can barely achieve continuous excitation, so that it is closed by a wormhole, and what is displayed in the field of vision of the "Tianma" is a "chaotic fish" that does not emit light or reflect. However, unlike the previous "Noah", this "Chaos Fish" is not completely invisible, and the two spheres and part of the crossbar are still exposed outside the wormhole. Sometimes, the "Tianma" still uses the method of "picking up the train" to enter the local space of the "Wild Goose", and at this time, the two crossbars can be seen bending backwards, forming a huge arc, as if the rushing vacuum has caused resistance to the movement of the heavy ball. The crossbar is truncated by chaos in the middle, and the outer sphere is not visible. Of course, this bend is not due to "wind resistance", but from the inertia of the heavy ball (which only exists during acceleration). The elasticity of the crossbar and the cable is excellent, when the acceleration reaches 10g, the crossbar is completely folded into the wormhole, only exposing the two spheres to the outside, and after that, even if the acceleration is increased, the bending of the crossbar will not increase, so this is a "constant resistance" design.

The speed of the "Goose Whistle" will reach more than half the speed of light, and this speed, combined with the "constant resistance" design, can ensure that the two heavy balls can withstand enough "vacuum compression" and stay outside the wormhole at all times. In this way, even though human civilization has fallen asleep, there are still two waking goose whistles near the earth.

During the flight, if the Pegasus is outside the wormhole, they can directly communicate wirelessly with the two people in the sphere; If the Pegasus is in a wormhole, it can only be mediated by the Goose Whistle. Ji Renrui carefully inquired about the condition of the two, and the two replied that everything was normal. They are now sharp-minded, energetic, and in the absence of other physiological factors (thirst, hunger, tiredness, sexual urges, etc.), they are better able to think rationally. After hearing these news, Yu Leshui is very relieved, but there is a limit to the relief, because being in good shape at the moment does not mean that it will always be good. As time passes, loneliness and irritability will be inevitable, and that's when the real test will be.

In the initial stages of flight, the ship had its back to the sun, then made a slow turn, and now it has changed to a circular direction. In order to monitor the state of the Earth at all times, the "Goose Sentinel" should revolve around the Earth, and the closer the better. However, the speed of the spacecraft cannot be lower than half the speed of light, so as to form a high-quality continuous wormhole, so as to maintain a dense vacuum inside the wormhole and cause enough space compression outside the wormhole. At the lowest velocity of half light, if the radius is too small, it will produce too large centripetal acceleration, which is more than the capacity of two human brains [Note 2]. Fortunately, today's passengers only have two brains, and the value of the blood supply system can be adjusted by the computer at will, which will not cause brain congestion during acceleration, so the tolerable acceleration can be greatly improved, up to 100g, but it is still limited. In order to keep centripetal acceleration below this value, the radius of the aircraft must not be less than 22 billion kilometers, which is quite far from the Earth, far beyond the Kuiper belt, and even beyond the range of the solar wind. But there is no way, this is the result of a balance of multiple factors, and there is not much room for choice.

Therefore, the "Wild Goose Whistle" can only stay outside the desolate solar system, keep its eyes open, prick up its ears, and always pay attention to the movements on the earth. In the right window, it will change its trajectory and go deep into the interior of the solar system in an elliptical orbit with large eccentricity, passing next to the Earth, which is for the convenience of communication between the two sides.

"On behalf of the Tianma, I would like to inform you of the Captain Xi of the Wild Goose Whistle that our observations have proved that your ship's flight is completely normal. We decided to stop our observation and return to Earth. ”

"Thank you, thank you, President Yu. It's a pity that we can't see off the Pegasus on its circumstance. On behalf of the entire crew, I wish the Tenma every success in its circum-orbital voyage and an early return to Earth – from the opposite direction, of course. ”

"Okay, all the crew of the Pegasus thank you for your blessings. Now I want to say a few words to my husband and Elaina. ”

The intercom was replaced by Chu Tianle's semi-synthetic voice: "Leshui, please speak, let's listen." ”

"Tianle, this breakup is likely to be goodbye. I will keep an eye on you on Earth. I will start writing "A Hundred Years of Collecting Shells" as soon as possible, and pick up every shell in our lives. This book not only deals with the two of us, but also reflects the storms of the times. ”

"Good. After writing a chapter, send it to me on the radio waves, I'm looking forward to it. ”

"Tianle, Elaine, as I leave, I want to be frank about my concerns."

"Please, we'll think hard about what you're saying."

"You and Elaine are acting as human goose whistles in the form of detached heads, which is an extraordinary action taken in extraordinary times, and I fully understand and support it. But lately, I've been feeling more and more that this is a bit sloppy, because ex vivo brain surgery has not been fully proven. How long does it survive? Can you keep a clear mind all the time? Is it true that you can maintain your original personality? Will you suffer from 'phantom limb' like other people who have had amputation – no, it should be 'phantom limb'? Will you become insane due to prolonged imprisonment or phantom disorder? In particular, you have such a great mission on your shoulders. ”

"Thank you for your frank warning. Elaina and I will always be on the lookout. ”

Yu Leshui smiled bitterly: "But this is also where my worries lie. Just as paradoxes in logic always arise from self-referentiality, can one make an objective evaluation of one's mental and intellectual state? It's hard, I'm afraid. Therefore, Tianle, Elaina, please try to maintain your own personality in future electronic communication, so that you can make as accurate judgments as possible in the form of 'mutual proofreading'. ”

Elaine said, "Okay. I sincerely thank Sister Yu for her warning and trust. I will remember it for the rest of my life. ”

"There are also Captain Xi and Chu Cao, you must also adhere to your own judgment when signing and implementing the execution. In particular, there is also the interference of father-daughter affection for you. You must put aside the emotional factor and make judgments on your own. ”

"Mom, I'll do it."

"President Yu, I will definitely do it."

Yu Leshui smiled and said, "Then let's talk about something light." Mingzhe, you call me President Fish, but I prefer another name. ”

Xi Mingzhe immediately said: "Mom, please rest assured, Cao'er and I will take care of Dad, and I will also take care of Cao'er." ”

"Okay, it's time for us to say goodbye, hopefully not forever. Tianle, live well, remember me! Cao'er, live well, take care of Dad for me! Goodbye! Goodbye Elaina! Goodbye to all the crew! ”

"Leshui, farewell!"

"Goodbye Mom!"

Ji Renrui also gave a farewell speech, and the farewell speech was very brief: "I just exchanged goodbyes with Mr. Chu Tianle, so I will give you the farewell speech just now: walk up first and then find the way!" Alive! ”

The crews of the two ships said goodbye to each other, and the "Pegasus" quickly withdrew from the "Wild Goose Whistle" in its native space. Now, what they see is a "Chaos Fish" and the two orbs it drags. The Chaos Fish swam by and disappeared into the depths of space, and the two orbs it was carrying quickly disappeared, but the radiolocation signal it emitted (through the spheres) was always clear.

4

On the way back, Yu Leshui was silent, quietly looking at the starry sky outside the porthole. Ji Jichang understood her mood and let the spacecraft fly at a low speed, maintaining a view of the outside world. Ji Renrui and Miao Qi sat in relative silence with her. Little Doudou on one side whispered to Emma:

"Mom, I found Grandma Yu very sad and didn't talk all the time."

"Hmm."

"I'll go and persuade Grandma Fish."

Emma smiled, "Can you convince her?" She suddenly had an idea, "Well, Grandma Yu said that she couldn't figure out how to determine the direction during the Huanyu voyage." I know you're very good at it, so tell her about it. ”

"No problem!" Xiao Doudou happily agreed. He walked over and gently took his grandmother's hand, "Grandma Yu, I heard my mother say that you want to know the principle of determining the direction in the circumstantial voyage, let me tell you, okay?" ”

Yu Leshui thanked Emma for her intentions and said with a smile: "Of course it's good, thank you to my little teacher." ”

Miao Ji also said: "Doudou said it, grandparents are also listening." ”

"Actually, this question is very profound and involves the nature of the universe. If the universe is flat, like a three-dimensional space in our intuitive senses, and it is very large, even infinite, on a very large scale, even infinite, then no matter which direction it keeps 'flying outward', it will not be able to return to its original place. But Einstein said that our universe is a hypercircle, which is self-curling and completely closed due to mass (gravity). But the three-dimensional hypercircle is intuitively difficult to understand, let's take the two-dimensional universe as an analogy, okay? ”

"Yes, of course."

"A sphere is the equivalent of a two-dimensional hypercircle, which is closed by curling, finite, but borderless. There is equality everywhere on the sphere, and there is no special center of the universe. If a two-dimensional person living on the sphere wants to sail around the universe, no matter which direction he goes, as long as he keeps moving forward, he will follow a great circle and return to the original place from the opposite direction. ”

"You're right, but you didn't say how to orient yourself." The fish is happy to tease him.

"Don't worry, I'm going to get to that in a moment. Now make a few assumptions: 1. Suppose that the circumference of the great circle of this sphere is 27.4 billion light years, and the half circumference is 13.7 billion light years. 2. Suppose that galaxies in the sphere are evenly distributed. 3. Suppose that the early part of all galaxies is a highly active galactic nucleus, that is, the earlier the galaxy, the brighter it is. And because it takes time for light to propagate, the farther away the galaxy is, the greater its absolute brightness. Galaxies are generally anisotropic, and when viewed from different directions, they will behave as different things, such as quasars, starburst galaxies, scorpion BL objects, Seifert galaxies, etc. It's hard to remember the names of these categories, but remember that the earlier the galaxy, the greater its absolute brightness, but the same galaxy will behave differently when viewed from different directions. These three assumptions are greatly simplified, but generally fit the characteristics of our universe. ”

"Okay, I remember."

"Now, suppose there's a two-dimensional person at the North Pole on the sphere looking at her two-dimensional universe – notice that in this two-dimensional hypercircle world, her gaze is going to bend along the sphere. The farther she looked, the larger the circle of latitude and thus the more galaxies she could see. When she looks beyond a quarter of her circumference and sees the equator of the sphere, which is the largest circle of latitude, she should see the most galaxies. Therefore, it is said that in her catalog, the stars with a distance of 68.5 billion light years are the most. ”

"Yes, your analogy is easy to understand."

"Further back, at a distance of half a circumference, or 13.7 billion light-years later, her gaze should converge on the South Pole on the far side of the sphere, where there should be only one galaxy. So in her catalog, there is only one galaxy at a distance of 13.7 billion light-years. ”

"It seems like it should be like this."

"But the observer doesn't know! She didn't know that her gaze had bent along the sphere to a point, and her intuitive impression would subconsciously tear and flatten the sphere, so that she could still see many galaxies at 13.7 billion light-years in all directions, and because of the different directions, the galaxy behaved as something different. ”

"Ahh

"If it's too complicated, I'll simplify it as much as possible. That is: if we find several pairs of quasars that are furthest from us in several pairs of relative directions, then they are probably the same thing. Further down there is a simple list: just look for this galaxy, use it as a beacon, and fly towards it all the time. When you reach this galaxy, you just have to keep your back to it. ”

"Has such a quasar lighthouse been found?"

"I found a pair, and the shape of both of them is basically a mirror image, with a redshift of more than 5, and the distance from the Earth is roughly 13.7 billion light-years."

"Really? That's great, it's simple for the ship to confirm the direction of flight. ”

"It's not easy. What we see is what they looked like 13.7 billion years ago. The Pegasus is a Mach 100 million spacecraft, and it only took 137 years to get there. But during this trip, the quasar will age rapidly, covering 13.7 billion years plus 137 years of life in 137 years. And it will quickly unfold in the field of view of the spacecraft observer, turning from a point into a huge galaxy. We must learn to recognize it. ”

"It doesn't matter. One hundred and thirty-seven years later, our little Doudou must still be alive and has become an experienced navigator. You're going to hold on to it, even if it's seventy-two variations. Okay, I get it, I get it completely. Thank you to my little teacher. ”

"Grandparents, do you understand?"

"Understood, understood, how can we not understand if you explain it so clearly?"

Xiao Doudou walked up to Emma with satisfaction and whispered, "Mom, Grandma Yu is not sad anymore, and besides, she completely understands that question, and her grandparents also understand." ”

"Well, you're such a competent little teacher. Go play. ”

Little Doudou left the command module happily. Ji Jichang quipped: "Aunt Yu, Xiao Doudou said that he explained the principle of orientation to you clearly. ”

Yu Leshui smiled, "That's right." He was very intuitive indeed, and generally correct. Perhaps the little ones are best suited to study cosmology, because the ultimate secret of the universe must be the most concise. Like Copernicus, he replaced Ptolemy's cumbersome current and average chakras with a concise and intuitive theory of the center of the sun. I believe that when you return, the university textbooks on cosmology will be greatly compressed. ”

Ji Jichang looked at her, and suddenly said, "Aunt Yu, I invite you again, please go with us to explore the world." My mom is determined not to go, and of course my dad can't go, but you are free. Don't say you're old, it's a burden to get on a spaceship. No, you will be the spiritual core of the ship, like a galactic nucleus with a huge gravitational pull. This circumnavigating the world is sure to solve many unsolved mysteries, such as quasars, dark energy, dark matter, the critical density of the universe, and you will witness these solutions. It's sure to be an exciting trip. ”

"Yes, I totally believe it."

She smiled and looked at the Ji couple opposite, "But unfortunately, I, like your mother, still have to stay on Earth." I am a very family-loving housewife, and I want to guard my home in the mountains, waiting for my husband, who only has a head left. Still, I appreciate the invitation. ”

Ji Renrui and his wife both smiled and said, "Changchang, don't persuade you, you can't break up." ”

Ji Jichang sighed and said no more. The roots of these three old trees were too deep to be transplanted onto the ship.

Pegasus made a stop at Jupiter on the way to replenish its inventory of liquid hydrogen before returning to Earth. Ji Jichang gave the crew seven days off to reunite with their loved ones for the last time. Seven days later, the three fleets of "Heaven", "Earth" and "People" set off at the same time, the "Heaven" team officially began the journey around the world, and the other two teams began the "Wisdom Preservation Journey" with the earth as the center. This time, many heavyweights came to the Halmahera Cosmodrome to see them off, such as the UN Secretary-General, the rotating president of the UN Security Council, SCAC representatives, representatives of the first session and the two chambers of the "Friends of Music", representatives of various countries, and the director of the office of He Guoji of China in the "Friends of Music". The Vatican did not send a representative, but it had been preceded by a prayer ceremony in Rome presided over by the head of the Pontifical Bible Commission, Bishop Lomac, praying for the success of the three fleets and praising the circumstance. After the ceremony, a reporter asked:

"Bishop Lomack, if this circum-universe journey proves conclusively that there is no Garden of Eden in the universe and that God has become a homeless man – which is very possible with the scientific community's understanding of the universe – will this affect God's standing in the minds of believers?"

Bishop Lomack smiled and gave a proper answer: "God does not need a concrete dwelling, he is in our hearts. ”

This witty answer became a famous quote of the times.

The farewell party was filled with a cheerful atmosphere – although there was still a faint sense of sadness in the tone. Since the discovery and announcement of Chuma Green 42 years ago, human beings have struggled to jump in the disaster of boiling water and vigorously implemented the awning plan, the human egg plan, the Noah plan, the wisdom preservation plan, the goose whistle plan, etc., which have become unprecedented great plans. A whole new era has begun for humanity. But all of the above plans are defensive and, to put it mildly, just an instinct to escape when disaster is at the top. Only circumnavigation is offensive, at least offensive and defensive, and it is the sublimation of instinct to ideals. Humanity's stride into the depths of the universe has been a breakthrough that would have taken thousands of years or more. But there is also desolation in the cheerfulness. After all, the success or failure of this expedition is uncertain, and it is difficult to predict whether the spacecraft will return to Earth in hundreds of years; And even if it returns, it is uncertain whether the civilization of the earth and even the wisdom of mankind have collapsed.

The current President of the Security Council, Hughesh, delivered a speech, which was broadcast live to the world:

“…… Before the invention of airplanes, although human beings had long had a yearning and imagination for the sky, their physical bodies were bound to the ground, and in essence they only belonged to two-dimensional creatures. Since then, the invention of airplanes has allowed human beings to leave the ground and have the eyes of the earth for the first time, and the spiritual realm is completely different, and human beings have also changed from two-dimensional creatures to three-dimensional creatures. But at that time, human beings were confined to the cramped near-Earth space, and could only use their eyes and imagination to tentatively outline the universe, and were essentially just caged creatures. Now, for the first time, the Mach 100 million spacecraft has given us the ability to look down on the macrocosm and the microscopic vacuum, and humanity will once again emerge as super-three-dimensional beings. Our spirit will encompass the universe of tens of billions of light-years, including the four-dimensional space and the fifth-dimensional ...... of time."

At the end, Hughish asked Yu Leshui to say a few words, and Yu thanked him and handed over the microphone to Ji Renrui. Ji also wanted to say goodbye, thought about it, and said: "I only want to say to my little grandson, do a good job, go home early, it's best to bring back an alien daughter-in-law to the Ji family!" ”

Everyone laughed, and the overly solemn atmosphere of the scene suddenly became lively. Miao Qi and Emma's mother held hands, both crying silently, and Yu Leshui hugged them in her arms. Kang Ping's wife and children also came to see him off, and the son held the portrait of the old man Kang Buming in his hand, and they wanted the old man to see the steps of mankind towards space.

Ji Jichang, who was far away in synchronous orbit, said goodbye to the earth on behalf of the 18,000 crew members of the three fleets: "...... Goodbye Earth, goodbye fellow human beings! We will never forget the roots of the earth and the roots of the mother race, and may the tree of humanity always be evergreen! He also said goodbye to the other two fleets: "The partners of the 'earth' team and the 'people' team, the old brothers of the Ji fleet back then, and the new brothers, let's set off at the same time but go our separate ways, I hope that at the end of the world, there will be a time to meet again!" Tian Mi and Ma Ming said goodbye on behalf of the other two fleets.

The bow of the main ships of the three fleets each burst into a cloud of white light, and the nine ships disappeared.

[Note 1] An instrument specially designed to observe the sun.

[Note 2] The spaceship inside the wormhole does not have centripetal acceleration, but objects outside the wormhole do.