Deep Space Wandering Fleet
Chapter 420 - 418 A New Era (End of Volume Seven)

Chapter 420: Chapter 418 A New Era (End of Volume Seven)

Lin Xuanyuan listened to Zhang Yuan’s narration and was silent for a while before suddenly saying, "The friendships among you guys always seem more pure. If I were you, I’d have cried my eyes out by now..."

A star drifted over from the light cluster behind, tracing a complex curve as it moved toward the front light cluster. This was due to the spaceship traveling at high speed.

"In our dorm, relationships weren’t very harmonious, you know, there’s always this or that kind of friction among the girls. If one girl’s personal life is a mess, it can make the whole dormitory environment toxic. Everyone forms their little cliques; you have no idea how complicated it can get."

"I haven’t heard you mention that before."

Lin Xuanyuan said, "Actually, it’s not a big deal, it’s all in the past... In the end, near graduation, everyone had a farewell meal and then dispersed, with all the new grudges and old resentments dissolving. There was never another chance to get together."

Zhang Yuan said, "There’s nothing to regret. In fact, the connections between people are not as tight as one might imagine. Sometimes, even when you’re invited to a gathering, you don’t feel like going. In a lifetime, having one or two friends is enough."

After pondering for a while, Lin Xuanyuan said, "Hey, yeah, what were their names? I can’t even remember anymore! What’s even sadder is that I can’t even remember what my mother looked like."

"I’m starting to forget what my father looked like as well... I can only remember when I see photographs," Zhang Yuan sighed.

The two of them fell silent for a moment.

Lin Xuanyuan then asked, "...If I suddenly died, would you cry?"

"Cry for what?" Zhang Yuan said with a smile, "Death is but a new beginning. One lifecycle ends, and a new life will begin anew. Dwelling on the past doesn’t serve much purpose."

"All I can wish for you is happiness in the new world, to live your next life well!"

Lin Xuanyuan was first taken aback, then smiled, "I also wish for you to have a future filled with success!"

...

In the last few years, Zhang Yuan stayed working at the Observatory, mainly teaching elementary and middle school students how to use astronomical telescopes and how to identify planets in the universe, including the direction of the Sun and of Gliese 581—places where humans were born or developed.

"If one day you become a Captain, it would be a disaster if you couldn’t find your way home!"

This job was very relaxing, not much workload, and each day was fulfilling and happy.

A bright little girl asked, "Grandpa Zhang, how should we navigate in the Universe? The Milky Way is in motion, everything is in motion, how should we determine the position of our spaceship?"

"Even airplanes on planets need navigation, so how should a spaceship navigate? Long-distance flights must be precise!"

Faced with this question, Zhang Yuan thought for a moment and took a sip of water. "It’s quite simple, there are three good methods."

"First, use accelerometers and gyroscopes, also known as the inertial navigation system. By measuring the acceleration and angular velocity at each moment, you can use integration to calculate the spacecraft’s velocity and displacement. The disadvantage of inertial navigation is clear: the longer the time, the larger the error, so it’s only suitable for short distances and auxiliary positioning."

"The second method is to locate by using the relative positions of known celestial bodies, observing the surrounding stars, setting up a system of equations. But as you said, everything is in motion, and distances measured by spectroscopy are constantly changing, and it’s quite difficult to measure with high accuracy."

"The third method is to navigate using fixed radio sources, which is the method we use now. In the Universe, there are a large number of pulsars that naturally emit periodic electromagnetic pulses. By observing multiple pulsars and forming a pulsar timing array, you have a natural deep-space network, also known as the ’Milky Way positioning system’."

"If you think that pulsars within the Milky Way are moving, causing a certain degree of error, you can even observe pulsars outside the Milky Way, over a hundred million light-years away!"

"For such distant stars, we can assume they are stationary."

Zhang Yuan then played several images of pulsars on the screen, which were like a series of man-made satellites continuously sending out signals.

These students, faced with truly complex knowledge, were all dumbfounded.

This one girl asked again, "If we venture out of the Milky Way and embark on intergalactic travel, how should we position ourselves?"

Zhang Yuan answered, "There is a phenomenon known as Fast Radio Bursts. These high-energy millisecond flashes are hypothesized to have very enormous sources, possibly from outside the Milky Way. Maybe, one day in the future, they could become beacons for humanity’s intergalactic voyages. These high-energy millisecond flashes are hypothesized to have very enormous sources, possibly from outside the Milky Way. Maybe, one day in the future, they could become beacons for humanity’s intergalactic travel."

"Cross galaxies?!"

The thought of so many natural beacons in the universe filled all the students with yearning, and they couldn’t help but look out the window, one by one.

Crossing galaxies seems so incredibly distant!

"Grandpa Zhang, I have another question, why are there just as many integers as there are even numbers?"

After a while, a plump little boy who had just started junior high asked another question.

His name was Wang Tiantian, and he had somehow heard about this topic; whether it be astronomy or geography, mathematics or chemistry, he asked about almost everything.

Children all admire power, and knowledge is power; in their eyes, Zhang Yuan was considered to be the most knowledgeable person around, and he was also a former captain with a very gentle temperament, basically able to answer all content. Here, the kids could even play on computers, so there were always a lot of children gathered around the Observatory.

"This question is too complicated!" Zhang Yuan laughed heartily—it was still too difficult to discuss the concept of "infinity" with kids of this age.

After pondering for a moment, he said, "Do you think there are more points on a 1-centimeter line segment or a 2-centimeter line segment?"

"Of course, there are more points on a 2-centimeter line segment! 2 centimeters are longer than 1 centimeter, shouldn’t there be more points on it?" The little chubby boy looked worried; this was a very simple question, wasn’t it...

It would be embarrassing if he got it wrong.

The students around him seemed to agree, and a few of the sharper ones cocked their heads without speaking.

Zhang Yuan smiled and said, "You’ve learned about functions, haven’t you?"

"Of course, I have."

"Then, you can draw the graph of y=√3x, right?"

This graph is simple; it’s a straight line that makes a 60-degree angle with the x-axis.

Zhang Yuan took a 1-centimeter cut on the x-axis, and the corresponding diagonal section was exactly 2 centimeters. He said with a smile, "According to this function’s graph, isn’t there a one-to-one correspondence between the points on the x-axis and those on the diagonal line, from (0,0) to (1,√3), which is exactly 2 centimeters? Every coordinate on the x-axis can be paired up one-to-one."

"Where, then, are the extra points that you say are on the 2-centimeter line segment?"

"If you can’t find them, we can only conclude that there are as many points on a 1-centimeter line segment as there are on a 2-centimeter segment, right?"

The little chubby boy, defiant, went off in search of the missing points, but he wouldn’t be able to find them no matter what...

In the end, he even launched a group assault, coming up with all kinds of crooked logic, like whether "0.9 recurring equals 1" and so on, only to be defeated very unwillingly in the end.

"Can’t find them, huh? Haha!"

Zhang Yuan said gloatingly, "Actually, according to our theory, bijection is a very important concept. There are as many points on a 1-centimeter line segment as there are on a 2-centimeter one; by some method, the points on a 1-centimeter segment and on a sheet of paper, or in other words, on a plane, are also the same in number.

"Even the points on a 1-centimeter segment and on a surface as large as Kunlun Mountain Spaceship, or even the points in the entire space of the universe... even any points in high-dimensional space, are all equally numerous, and can be matched up one-to-one using certain methods."

"That is, the number of points on a one-centimeter line segment is the same as the number of points in the entire universe!"

"Ah?" Not only was this chubby little kid surprised, but a whole bunch of students behind him exclaimed as well.

They could never imagine that such a small segment could compare with the entire universe – how is that even conceivable?

Allowing these children to exhibit expressions of shock and amazement, marveling at the mysteries of the universe, had become a great pleasure for Zhang Yuan.

Zhang Yuan smiled and said, "But infinity also comes in sizes. The set of natural numbers, in mathematical terms, is called Aleph 0, which is the smallest infinity."

"The smallest infinity?"

"The number of points on a line segment – that is, the infinity formed by real numbers – is known as Aleph 1."

"...All possible mathematical functions: the number of continuous and discontinuous functions is called Aleph 2."

"I get it, there’s also Aleph 3, Aleph 4, Aleph 5!" The little chubby kid shouted, as if he had discovered something powerful.

Students of this age are always so melodramatic, gaining a little bit of knowledge that they can show off to their peers.

Zhang Yuan laughed and said, "Yes, it can extend infinitely upwards... But it’s very hard to find a specific meaning for higher dimensions of infinity in reality. It can only become a string of symbols on paper. Moreover, a difficult mathematical problem is whether there exists an infinity greater than Aleph 0 but smaller than Aleph 1. This question is known as the Continuum Hypothesis."

"The Continuum Hypothesis may be a hypothesis, but it can never be proven or denied. So it just sits there all alone, it has existed for nearly four thousand years and remains unsolved to this day."

"Why?" Wang Tiantian asked again, this world was too strange.

A problem that hasn’t been solved for four thousand years. He was getting excited inside.

Zhang Yuan laughed loudly again: "That’s... a different story altogether, called Gödel’s Incompleteness Theorem! The history of mathematics is yet another magnificent journey. There are so many problems in the world that cannot be solved!"

...

Days passed by one after another, and as aging continued, the body became weaker every day.

Even the journey to the Observatory felt exhausting, yet he still insisted on working, answering the children’s questions – which could be said to be his greatest pleasure after all his friends had withered away.

On that day, the doctor who came to examine him showed a very regrettable expression, she said very gingerly, "Old Captain, your physical condition has reached the standard for entering the Virtual World."

"I will file a report for you. Your wife has also reached the standard. By the end of this month, if you’re willing..."

"Is that so... I’ve truly lived long enough." Zhang Yuan nodded and sighed, "I have no objections, it’s time for me to say goodbye to this era."

On August 29, 5812, Zhang Yuan, the first Captain of the Kunlun Mountain Fleet, was about to leave this world.

Cannons fired momentarily in the starry sky before fading away without a sound.

Currently, 90% of the population was in hibernation, without a specific need to be awakened. The remaining 10% of the conscious population spontaneously participated in this farewell ceremony.

Many activities in Kunlun Mountain ceased, and the schools had a day off, an honor Zhang Yuan truly deserved.

"Do you have any last words?" the doctor asked.

Countless younger generations were watching him, expecting him to say something, be it encouraging or something else. Some of the older people were wiping tears incessantly, this time, he was not the last to go.

"No more. Everyone is doing well, keep moving forward," Zhang Yuan said with a smile: "The future is up to you."

Several staff members helped him up from his wheelchair and laid him down.

The Hibernation Chamber felt like a soft mattress, very comfortable to lie on. Zhang Yuan turned his head, looking around.

One by one, former friends and colleagues were bidding him farewell.

It seemed there weren’t many left.

The feeling was subtle; Zhang Yuan was not a man who feared death, but at that moment, he still felt as if he couldn’t catch his breath.

He suddenly remembered—

When he was very small, the instant he understood what death meant, he squatted in the corner and sobbed uncontrollably.

"Can I... not die?" Zhang Yuan asked with tears in his eyes.

"What does immortality mean?" his father, Zhang Qiming, replied.

"Just... to live forever."

"Oh, you mean... you want to live forever." Zhang Qiming pondered for a long time, saying seriously, "I think it’s better to die. Man cannot achieve immortality."

Young Zhang Yuan couldn’t accept this answer at the moment, although many of his father’s responses were very baffling.

Zhang Qiming said, "I think you might imagine the duration of immortality to be too short. Immortality means infinite, a hundred years, ten thousand years, a hundred million years, even a hundred quintillion years, compared with infinity, are no different from zero."

"In the eyes of true Immortals, the universe might reach heat death in a second, that is, all the happiness you feel on Earth only exists for a very short time. What follows is a long existence in the vast empty universe alone. Without any matter, without any company."

"Until waiting for that faint chance of a cosmic big bang in the quantum sea, to start anew. But how much time will that take?"

"This kind of solitude might be unbearable for humans, or their way of thinking may evolve into another species, or they may stop thinking altogether... I think, it’s better to stop thinking, to choose death," Zhang Qiming looked up at the azure sky, stroked Zhang Yuan’s head, and said earnestly.

Even so, young Zhang Yuan didn’t understand at all what his father was saying...

For some reason, just before Zhang Yuan left this world, he remembered this conversation.

Perhaps, the dead hero is the good hero.

Just... how lonely...

Amidst the tears, Zhang Yuan faintly heard sobbing. He didn’t know who was crying.

He lost consciousness quickly in his drowsiness.

...

One era had ended, and another had immediately begun.

Humans would not stop their strides because of this; this grand journey was still continuing...