The stars, but they become the gray wind

"Uh...could it be that we have reached a bottleneck?" Luoying asked curiously.

“It’s not a bottleneck…it’s a technological singularity.”

"Equal Cluster Tumor Research (V) VIII Phosphorus Division Phosphorus Five, etc...Technological Singularity?"

"I think your development speed is quite fast... I remember your civilization was born 120,000 years ago, right? 117,975 years ago... So, at this time, it's only been a little over 2000 years since your civilization was born?"

"yes……"

"And the key point is... as an intelligent species created by the Tree of Life, you have already formed civilization when you were just born..." Thinking of this, Luo Ying suddenly realized that he seemed to have overlooked a certain point before.

"It took the human species I originally belonged to at least millions of years to evolve intelligence and form the most basic civilization structure, but your development process... uh..."

"Just over 2000 years have passed since the birth of our species, and you've already become a bona fide Type 1 civilization? It took humanity millions of years to cover 73% of this distance, and you've compressed it into just over 2000 years. Isn't this considered a technological singularity?"

"Actually, from our perspective, the technological development during that period was a bit slow. Given our talents at the time, it could have been much faster. The current view is... that these 2000 years could be compressed by about a quarter. At the rate of development back then, the Sky Alien civilization could have become a Type I civilization in around 1500 to 1600 years."

"After all, the Sky People have possessed a strong sense of purpose since their birth. They leverage their ability to explore and understand the laws of nature and the universe to form a symbiotic, positive feedback loop with the Tree of Life."

"Since the birth of the Sky Star civilization, all individuals within it have enjoyed material and spiritual supplies far exceeding their actual needs. Therefore, the people of Sky Star are more accustomed to relatively less hasty planning and scheduling. This is why this journey, which originally only took about 1500 years, took the Sky Star civilization an additional 500 years to complete."

"Even after acquiring the ability to venture into space, the Sky Star civilization didn't rush into large-scale development of the entire galaxy. Instead, they chose to first experiment with building orbital rings and perfecting their own artificial ecosystem technology."

"However, after the orbital ring was completed and the attempt to create an artificial ecosystem in the ring was successful, the extra 500 years of accumulation, nearly a quarter of the time spent by Sky Star over the past 2000 years, finally ushered in the peak of its development. Sky Star's civilization development began to enter the stage of technological singularity. After the arrival of this technological singularity, all preparations for Sky Star's entry into deep space have been basically completed, and Sky Star civilization will enter the stage of interstellar civilization development."

"Remember that biological spaceship from earlier? After the Tree of Life's secondary improvements, this early spacecraft's exhaust velocity reached over 300 km/s. While maintaining this specific impulse, it could also maintain a long-term acceleration of 1g. The engine's performance was already sufficient for Sky Star to develop the entire galaxy. However, it was still too slow for the Sky Star civilization at the time. Therefore, a series of more advanced propulsion engines were proposed."

"For example, the nuclear saltwater propulsion engine was a very common engine at the time. Spacecraft using this engine accounted for over 40% of the total number of spacecraft at the time. Its exhaust velocity reached 4500 km/s, and it could sustain accelerations exceeding 1g. As a rare type of torch engine with both high specific impulse and high acceleration, it was the most common choice for the Sky Star people when choosing their spacecraft..." (Note 1)

"Wait, wait...you said a nuclear salt water engine...and the exhaust speed is 4500km/s?! That's 1.5% of the speed of light?" At this time, Luoying suddenly raised her hand to interrupt Elena.

"Yeah, what's wrong?"

"You guys use the saltwater version of the nuclear engine that uses 90% weapons-grade enriched uranium?"

"After all... if the concentration of enriched uranium is reduced, the specific impulse and acceleration will become ugly, right?" Elena said calmly.

"Hiss... wait a minute... Even in my understanding, when people talk about nuclear saltwater engines, they're basically referring to the one that uses 20% enriched uranium at the nuclear power plant level, with a specific impulse of 6600 seconds and an exhaust velocity of 66 kilometers per second. Not that black-tech version of the nuclear saltwater engine that's based on my Greenskin idea and has an exhaust velocity of 1.5% of the speed of light. And you guys are using that thing right off the bat? Aren't you afraid... you might get killed by using it?"

"It's okay... Initially, we did consider using a low-enriched uranium version of the nuclear salt water propulsion system, but the specific impulse and exhaust velocity of the low-enriched salt water propulsion system were a bit disappointing. In addition, the materials technology at the time also allowed us to directly manufacture materials that could withstand the 90% enriched uranium nuclear salt water propulsion system. The fuel tank, reaction chamber, nozzle and other related materials and manufacturing processes were not a problem. We were already able to produce heat-resistant materials that could withstand temperatures of nearly one million K. As far as we were concerned, the neutron radiation from the nuclear salt water was not a big problem. After all, as long as we were not directly exposed to the high temperature of the reactor, even huge amounts of neutrons or ionizing radiation would be basically the same as sunbathing to us. Although absorbing too much radiation does tend to overactivate the nanomachinery in our bodies, resulting in blue lines with radiation on our bodies and causing our body temperature to rise too quickly, it is indeed a negative effect, but at the time, it was not a big problem."

"No, that's not what I mean... The nuclear salt water thruster... you know... The tail flame of the torch thruster has always been ridiculously long, and it's normal for the plasma tail flame produced by a 90% concentration nuclear salt water engine to reach hundreds of kilometers in length... This thing... doesn't seem to be something that can be started within the low-Earth orbit of a planet, right?" Because of the personal hobbies of Carlisle, who was called the leader by everyone, and the information about aerospace engineering that she sent when chatting in the group in the past, Luo Ying unexpectedly gained a lot of understanding in this area, of course, including the crazy idea of ​​Dr. Zubrin who proposed this engine type.

"You're asking about that... Regarding this, the main docking ports and launch locations for these types of spacecraft at the time were at the 100,000-kilometer-high terminal area of ​​the equatorial space elevator. That location was also far away from the main body of the planet and the main part of the orbital ring. Several orbital elevator terminals at an altitude of 100,000 kilometers had spaceports specifically responsible for docking nuclear salt water torch spacecraft. At that time, nuclear salt water engine spacecraft generally used their own additional chemical propulsion or tugboats to start their nuclear salt water engines after leaving the port at a sufficient distance."

"However, from the perspective of that time and later generations, the radiation and high temperature carried by the salt water engine ejection are not a big problem for the planetary environment of Sky Star itself. Most plants and animals in the biosphere of Sky Star have the ability to survive after absorbing large doses of neutron radiation from radioactive substances or ionizing radiation from various rays. The Tree of Life itself also relies on absorbing ionizing radiation from the sun for survival. Even if the nuclear salt water engine is turned on in low-Earth orbit, the radiation-carrying high-temperature plasma tail directly enters the atmosphere, and it will hardly cause any harmful effects on the ecosystem of Sky Star. The radiation entering the atmosphere will quickly be absorbed by the planetary life form of the Tree of Life. As long as the nuclear salt water engine's tail flame, which is hundreds of kilometers long, does not burn directly at the ground, it will basically have no negative impact on the ecological environment of Sky Star."

"Uh... the torch engine firing at the planet's surface... that scene... I don't dare to imagine it anymore..." Hearing this, Luo Ying muttered in shame.

"And the ability of the creatures on your planet to adapt to and utilize strong radiation is indeed a bit abnormal."

"But... I have another question. Where do you get so much enriched uranium? This heavy element should account for a very small proportion of the entire planet's composition, but given the production and scale of your nuclear saltwater spacecraft, your weapons-grade enriched uranium production must be over 10 million to 100 million tons per year. That's simply not sustainable, right?"

"Well... you know that the naturally occurring nanomachines on our planet allow us to utilize any material and mineral on it with extremely high efficiency. Another, and most crucial, point is... the composition of our planet. Our research into the composition of the planet has made us even more convinced that the trajectory of our galaxy may have been interfered with by some entity..."

"In short... the content of heavy elements in our planet is a bit... scary." After careful consideration, Elena finally used this word to describe it.

"Scary? How scary?"

"You should know this, right? Uranium, element 92 on the periodic table, is the heaviest element found naturally. Radioactive heavy elements like uranium make up nearly 18% of our planet's composition. Therefore, our entire planet is overflowing with radioactive heavy element minerals."

“…………Fuck” After hearing Elena’s answer, Luo Ying was silent for a long time, and then used one word to express his countless thoughts.

"Nearly 20% of the planet is made up of radioactive heavy elements? Isn't the composition of the main elements on your planet a bit too strange?"

"In fact, for a long time, we have always regarded this state as normal. After all, our civilization has lived in this environment since its birth. Without comparison, we didn't feel anything was wrong. It was not until the advent of the era of space exploration that we realized the various anomalies in the composition of celestial bodies and the gravitational structure within our galaxy through comparison with the composition of other celestial bodies..."

"And what's more... the abnormalities in the composition of our home planet and the surrounding celestial bodies are far more than just this..."

"Uh...aside from such a high proportion of heavy elements, is there anything more outrageous?"

"In that regard... there's also the strange phenomenon of tritium isotope content. The natural tritium isotope content in the Sky Star strata is also abnormally high. As an isotope of hydrogen that only accounts for less than 1% of the total material content of the strata, under normal circumstances, the tritium content in the strata should be negligible. Moreover, tritium's extremely short half-life makes it almost impossible for it to be preserved in the strata for a long time. However, the composition of the planets on Sky Star is quite counterintuitive. The tritium content accounts for nearly 5% of the total crustal material, and all of this tritium is located very close to the surface. This strange phenomenon, which violates the common sense of planetary formation theory, has puzzled us for a long time. For this reason, we even specifically asked the Tree of Life itself to confirm whether the strange composition of the planets on Sky Star was caused by its influence."

"And what was the result?" Luo Ying asked.

"The answer the Sky Star civilization received from the Tree of Life was negative. According to the Tree of Life's memories, the strange composition of the planet Sky Star existed when it first began to grow on the planet, billions of years ago. At that time, the Tree of Life was still far from controlling the planet. The internal elemental composition of Sky Star was already in this state. It also noted the abnormally high content of radioactive heavy elements on Sky Star, as well as tritium isotopes that had been stored for far longer than their theoretical maximum half-life."

"Just like the original nanomachines that formed the basic cells of the Tree of Life, we ultimately did not understand the fundamental reason for the high proportion of radioactive elements on Sky Star. Perhaps the 'Creator' who created the Tree of Life and Sky Star civilization did it intentionally. For Sky Star, such a huge amount of radioactive elements is indeed a huge gift."

"At least for ships equipped with nuclear saltwater engines, which require massive amounts of enriched uranium for each voyage, Sky Star's abundant radioactive mineral resources are truly a treasure trove. It's precisely because of Sky Star's naturally abundant radioactive heavy element minerals that the widespread adoption of nuclear saltwater engines using 90% enriched uranium has become inevitable. Otherwise, if we were in the same civilization as you, we probably wouldn't be able to afford nuclear saltwater propulsion at all."

"Indeed... Compared to you guys who were able to produce hundreds of millions of tons of weapons-grade enriched uranium annually over a hundred thousand years ago, our Type 0.73 civilization is really a bit lacking... I remember my friend named Kalisi sent me some information about the enriched uranium reserves before the collapse of the Soviet Union?"

"I remember the data in that document Kalisi sent me. It seems like before the collapse of the Soviet Union, they had stored 1200 tons of weapons-grade enriched uranium with a concentration of over 90%?"

"Compared to your annual production of hundreds of millions of tons, and this is your production capacity from 100,000 years ago, this reserve is so low that it can be ignored. It's like an ant encountering an elephant."

"Actually... the reason our production of enriched uranium and other types of radioactive heavy elements is so high is simply because of the planet's unique advantages, right?"

"But this isn't just some minor advantage, is it? This alone has created a chasm-sized gap between you and other civilizations. After all, what civilization could easily mass-produce and popularize Torch Ships the moment they ascend to space? Furthermore, these aren't just ordinary Torch Ships with relatively low specific impulse and exhaust velocity; they're monstrous-class Torch Ships with an exhaust velocity of 1.5% the speed of light. This isn't just a technological advantage; it's a crushing advantage over other civilizations."

"While other civilizations are still slowly honing the efficiency of their torch engines, which only have a specific impulse of around 20,000 seconds, you have already achieved interstellar travel with torch engines that have an exhaust velocity of 1.5% of the speed of light."

"What happened next? Now that we have a Torch Engine of this level, it should be easy to develop every celestial body in the entire star system, right?"

"After the development and production of the nuclear saltwater engine was completed and widely used, the Sky Star civilization began to spread its footprints across the entire Sky Galaxy at a rapid pace, and within the next short period of less than half a century, they established colonies on every celestial body in the Sky Galaxy."

"Over the past half century, Planet One's crust has been stripped of an entire outer crust and has become part of the Dyson Cloud of stars. The massive amount of energy provided by this Dyson Cloud has further caused the technology and energy output of the Sky Star civilization to explode exponentially. At this time, the history of the Sky Star civilization has only been less than 2500 years old. Compared to the hundreds of thousands of years that followed, this period is not even a fraction of it." Elena calmly narrated the somewhat shocking development process of the Sky Star civilization.

Note 1: A less recognized standard for flare vessels is a specific impulse greater than 20000 seconds and an acceleration greater than 0.01G.

As for the torch engine in general, it refers to those engines that work miracles with great power, have extremely high output power density, and can simultaneously achieve high thrust and high specific impulse (low fuel consumption).

Generally speaking, for a given thermal power, high specific impulse and high thrust are mutually exclusive. Given a given thermal power, the higher the specific impulse, the greater the V (for the same fuel), and the lower the thrust. For example, in real-world electric propulsion, the specific impulse is high, but the thrust is extremely low, at most a few Newtons.

In near-future science fiction, the engine's specific impulse must be high, otherwise V will be insufficient. However, we also want to design spacecraft with good maneuverability, which requires sufficient thrust to achieve a high thrust-to-weight ratio and reduce acceleration and deceleration times.

This combination of high specific impulse and high thrust, while also complying with the laws of physics, ultimately results in an ultra-high-power engine. When operating, this engine produces a long and extremely bright tail flame, resembling a giant torch, hence the name torch engine, and spacecraft using this engine are called torch ships.

The specific principle of the torch engine is not fixed, it can be nuclear fission/nuclear fusion/matter-antimatter annihilation. This name is used to refer to all types of high specific impulse, high thrust, ultra-high power engines, and those that can travel a nearly straight route between the starting point and the destination.

Chapter 121 Civilization Classification and Antimatter Spacecraft (5000 words)

Dark blue and dark green patterns dot the outer surface of the orbital ring surrounding Sky Star. Heavy fusion reactors, cold fusion generators, and solar arrays as big as mountains are distributed in a very regular pattern on the outer surface of the ring. In addition to these conventional energy supply facilities, the huge ring framework itself also utilizes the planet's own gravity and relies on its own huge body to continuously cut the planet's magnetic field lines to obtain additional energy. The ring, built on Sky Star's synchronous orbit, has accompanied Sky Star for more than 100,000 years since its completion. During these 100,000 years, the main structure and infrastructure of the ring have also undergone countless iterative upgrades and renovations. The number of space elevators connecting the ring to Sky Star's surface has also increased from the original 6 to 87 today.

On the sea surface in the equatorial region of Sky Star, a small cabin is slowly rising from the space elevator ground base station on the sea surface, heading towards the orbital star ring above the clouds.

"Elena... I thought of an interesting philosophical debate..." In the luxuriously decorated and comfortable elevator car, Luo Ying, who was sitting by the window, looked at the endless ocean below and said to the ground base station which was gradually getting smaller as the elevator car rose higher.

"Oh, a philosophical debate? How about you tell me about it?"

"This topic was discussed with my friend Carlisle..."

"The philosophical topic we were discussing at the time was: As a living being, could cyanobacteria be more advanced than industrial-age human civilization?"

"Cyanobacteria were among the earliest life forms on Earth. In the early days of life on Earth, more than 30 billion years ago, vast quantities of cyanobacteria almost covered the entire Earth's oceans. The total energy power of these cyanobacteria, harnessing sunlight, was far greater than that of Type 0.73 pre-space-age human civilization billions of years later."

"Humanity has developed civilization for thousands of years, but the total energy output it has created is even less than that of cyanobacteria billions of years ago."

"As both living organisms, cyanobacteria have a much higher Kardashev energy output level than humans."

"Does the cyanobacteria know that their total energy output is higher than that of humans, intelligent beings? Obviously not."

Because the Kardashev civilization classification system presupposes that the object of evaluation must first be a civilization. If it is a bunch of unintelligent organisms like cyanobacteria, then no matter how high the total energy output it creates, it cannot be judged using the same standards for civilizations."

As a reference and standard for grading and judging civilizations, the Card-type civilization grading system may not be a very good standard, and grading based solely on energy output is obviously inaccurate."

"The three elements that measure the level and scale of a civilization's development should be the total amount of matter, information, and energy."

"These three elements are like a three-legged stool; none of them can be missing."

If we simply classify based on energy output, we will end up with some very inaccurate judgments.”

"For example, a civilization that simply replicates a low-tech civilization on a large scale might have a higher Kardashev scale than a truly high-tech civilization. Similarly, a Type 0.8 Kardashev civilization born from coal burning and a Type 0.8 civilization born from controlled deuterium-tritium nuclear fusion technology clearly cannot be lumped together."

"So, classifying a civilization solely based on energy may not be comprehensive or accurate."

"I agree with this. Judging a civilization's level of development solely by its energy output is too simplistic. It doesn't fully reflect its actual state and scale."

"If we judge the current Sky Star civilization in this way, we can only come to the simple conclusion that the energy output power of Sky Star civilization is around Type 2.7."

"For a civilization on Sky Star that has already mastered 5000 star systems within 300 light-years, what we clearly need is a more precise standard for judging our own civilization."

"Suppose a Type II civilization in a main-sequence star system and a Type II civilization in a neutron pulsar system both harness the energy of a single star, but their energy output power differs dramatically. Neutron stars radiate over a million times more energy than a normal main-sequence star. The actual power output and technological level of a civilization that can fully utilize all the energy of a main-sequence star and one that can utilize all the energy of a neutron star could be incredibly different."

"Similarly, the technical and engineering difficulties of establishing stellar-scale astronomical engineering on a gentle and stable main-sequence star are incomparable to those of establishing stellar-scale engineering on a violent neutron pulsar."

"Another way to categorize a civilization's level of development is through a civilization grading index based on the scale of matter they control and master. A higher degree of mastery and manipulation of the underlying laws of matter means repeated technological explosions and singularities. Materials science is the most basic and crucial key and foundation for the development of all new technologies. For example, the human civilization you once lived in had already achieved elementary manipulation and editing capabilities for matter down to the nanoscale, or molecular level."

"As for the Sky Star civilization, its energy output has reached Type 2.7, and its material power has reached the atmite level. By constructing a macroscopic structure of elementary particle materials with integrated printed arrangements from elementary particles like quarks and gluons, we have built a superluminal communication network centered on Sky Star and radiating outward for 300 light-years. This network is based on a giant photon entanglement array. Although the speed of macroscopic material transportation between galaxies makes it almost impossible to conduct any form of logistics, we can communicate with the other 5000 galaxies relatively without delay. Although the bandwidth of this information communication is often limited and can only transmit simple text messages such as 0s and 1s, in order to transmit more complex information such as images, we can only perform a series of complex transcoding, converting a large string of 0s and 1s into images or videos in a fairly complex way through computers and artificial intelligence."

"Although this method of communication is subject to considerable limitations, we have still created a truly intergalactic instantaneous communication network."

"And the advanced materials science technology brought about by our ability to deeply manipulate matter allows us to develop various extreme celestial bodies in the universe..."

"We've utilized the powerful magnetic fields naturally present in dozens of neutron stars around our home galaxy to create a series of giant power generation facilities. The most famous of these is the neutron pulsar we call the Dawn Star. Historically, this pulsar, located less than ten light-years from our home galaxy, is the brightest object in the night sky. On a clear night, you can see this brilliant neutron pulsar almost with the naked eye, without any additional observation equipment."

Surrounding this neutron pulsar are 15 neutron-simple material shells, each 1000 kilometers in diameter and comparable in size to a dwarf planet. These 15 artificial celestial bodies are arranged in an equilateral ring around the neutron pulsar. As the neutron pulsar spins at a high speed of up to 1000 revolutions per second, its magnetic flux lines constantly cut through the 15 surrounding artificial celestial bodies. As these 15 artificial celestial bodies cut through the neutron pulsar's strong magnetic field, they act like a giant celestial-sized generator, generating a constant supply of energy by cutting through the magnetic field of the rapidly spinning neutron star.

"This power generation facility built on a neutron star can collect hundreds of thousands of times more energy per second than a normal main-sequence Dyson Cloud. Even the energy output of a giant Dyson Cloud in the galaxy above, obtained by dismantling an entire planet, pales in comparison to this neutron star power plant."

"You have to know... the Dyson Cloud in the Sky Galaxy was originally the product of dismantling Planet One, the closest and lowest orbiting star. For hundreds of thousands of years, the Dyson Cloud facility in the Sky Galaxy has been operating at an extremely close distance to the star, continuously absorbing stellar prominence material and jets to replicate itself. After nearly a thousand years of long-term proliferation and self-replication, the Dyson Cloud in the Sky Galaxy has achieved a collection and utilization rate of over 65% of the star's total energy. In order to avoid blocking the stellar radiation and light received by the planet Sky Star and the colonies on this celestial body, the Dyson Cloud's orbit must be frequently adjusted. As a G-type main-sequence star, the Dyson Cloud receives over 60% of the total energy every day, which is not even as much as the energy output per second from the neutron star power generation facility."

"In addition to a series of neutron star energy giants including the early morning stars, black hole celestial bodies around the parent galaxy are also important sources of energy and matter for us, as well as important acceleration tools."

"The first objects we exploited were naturally the two Kerr black holes located less than 0.5 light-years away in the galaxy in the sky. The properties of these two Kerr black holes spinning around each other at high speeds were used to accelerate spacecraft for quite some time."

"Perhaps it's a coincidence of nature, or perhaps it's the work of that mysterious 'Creator,' but these two Kerr black holes are axisymmetric black holes that rotate around their axes without changing with time, and surprisingly, neither of them has an accretion disk. This gives us considerable convenience. In the early stages of interstellar expansion, we only need to launch probes at these two black holes and have the unmanned probes continuously perform gravitational slingshots around them. After a sufficiently long acceleration period, we can accelerate the probes to speeds infinitely close to relativistic speeds, that is, the speed of light. Through this method, our unmanned probes have conducted advance close-range surveys of the large number of galaxies along the way they arrived today, and confirmed the environment within the local galaxies. Although we didn't find any traces of intelligent life within the surrounding 300 light-years at that time, we are still developing towards the interstellar civilization stage according to plan."

"Come to think of it, if I'm not mistaken, the farthest unmanned probe has flown nearly 20,000 light years so far, right?"

"The last time we received information from this probe, now 20,000 light-years away from the galaxy in the sky, was tens of thousands of years ago. We even thought it had long been lost in deep space, out of power or damaged. But then, tens of thousands of years ago, we unexpectedly received a message from this probe, nearly 20,000 light-years away, before it slowed down behind a star."

"To this day, this probe still holds the record for the farthest-flying man-made spacecraft in the history of the Sky Star civilization."

"I still remember... when we launched this probe, the Sky Star civilization's spaceflight speed was far from reaching the speed of light. Even the fastest matter-antimatter annihilation propulsion engine at the time could only accelerate the spacecraft to around 0.7 to 0.8 times the speed of light. To accelerate the probe to a higher speed, we borrowed the twin Kerr black hole system, allowing the probe to be accelerated to an incredible speed close to the speed of light as it orbited the black hole's gravitational slingshot. Ultimately, with a small change in angular velocity, it was flung into the depths of the universe at a speed close to relativistic speed."

"The entire process took nearly seven years. The first year was spent transporting the probe to the vicinity of the twin Kerr black hole system and launching it toward the black hole after it was filled with antimatter fuel for propulsion. The subsequent acceleration process lasted seven years, or seven years on the external time scale. Perhaps for the probe, in the region extremely close to the black hole's gravitational influence, only a few minutes or even seconds may have passed in the probe's own time reference frame."

"I understand... Is it the strong gravity of the black hole that causes time to slow down?" Luo Ying said to herself as she looked at the beautiful scenery outside the window.

"But this short acceleration process, from the outside, seems to have taken seven years? From what I know about your style and efficiency, this is indeed a very radical plan."

"You think it's radical? No... I don't think so. Ever since the birth of the Sky Star people, we've had this inexplicable and abnormal love for space. Therefore, in the early stages of our economic expansion, relying on those two black holes, we launched a large number of probes. Under the blessing of the gravitational slingshot of the binary black hole system, after being accelerated to a high enough speed, they each rushed towards their target galaxy, becoming the pioneers of Sky Star's interstellar exploration."

"Once the probe confirms that no other forms of life exist locally, we will launch a payload of tissue containing a portion of the Tree of Life and a large number of nanomachines, or even seeds separated from the Tree of Life, to that galaxy. This cargo will arrive at the target galaxy first, along with a second batch of unmanned spacecraft, similarly accelerated to near-light speed by the gravitational slingshot of the binary black holes. We will then deploy nanomachines, Tree of Life tissues, and seeds on the planets in the target galaxy. The Tree of Life tissues and seeds released onto the planet's surface will grow rapidly with the help of the nanomachines."

"By that time, our von Neumann self-replicating machine technology was already quite advanced. We had fully understood the composition and microstructure of the natural nanomachines on Sky Star, and used this to create our own version—called micro-building block antimatter energy self-replicating nanomachines."

"This most microscopic nanounit is only the size of a single proton or neutron. With a built-in antimatter energy source, the von Neumann nanomachine can continuously replicate itself through the trace amount of antimatter stored inside. It can also modify its own atomic nucleus-scale structure at will when needed, forming almost any material we desire."

"Even with electron- or neutron-degenerate materials, antimatter nanomachines can still be mimicked and fabricated as tiny building blocks,"

"The antimatter energy built into these tiny building block nanomachines and their significantly smaller size compared to their predecessors allow us to appreciate this new generation of von Neumann self-replicators far beyond those using heavy or cold fusion technologies."

"There's no doubt that the widespread adoption of nanomachines is another huge leap forward for Sky Star, representing a further advancement in Sky Star civilization's ability to control microscopic matter."

"The Sky Galaxy houses a giant circumstellar particle collider that is the oldest and largest in the entire civilization."

"This solar accelerator has a circumference of over 9.4 million kilometers, which is almost as long as your planet orbits in one year. The entire accelerator uses a fully enclosed casing, equipped with technology sufficient to withstand the stresses of a star's gravity."

"The driving energy for the massive circumstellar particle accelerator comes from a portion of the Dyson Cloud. The Dyson Cloud, which utilizes over 60% of the star's energy, uses some of that energy to power the circumstellar particle accelerator. Besides studying the microscopic structure of particles, the circumstellar accelerator also has a crucial mission: to produce and store sufficient amounts of antimatter deuterium and positrons."

Every minute and every second, the Dyson cloud orbiting the sun in a low orbit is constantly absorbing the radiation, light and heat emitted by the star, and occasionally absorbs some prominence matter as a supplement to accelerate its own replication speed.

As a G-type main-sequence star, the CNO cycle nuclear fusion of the Sky Galaxy star consumes nearly 500 million tons of matter every second, releasing a huge amount of energy into the surrounding space, and 65% of it will be intercepted by the Dyson Cloud and transmitted to the Circumsolar Accelerator in the form of a wireless long-distance energy broadcasting device within the star system, providing the Circumsolar Accelerator with a steady supply of energy for the production of antimatter. The huge Circumsolar particle accelerator will produce about 50000 tons of antideuterium per second, and about 15768 billion tons of antimatter fuel per year. The antimatter fuel produced by the accelerator is sent to a vacuum magnetic field container for storage, and provides fuel for all spacecraft in the Sky Star star system that are powered by matter-antimatter annihilation.

For interstellar travel, the speeds achieved by fusion-based torch engines, with exhaust velocities limited to only 9% to 12% of the speed of light, are far too slow, and the energy generated is too small. The fuel mass required to achieve subluminal or near-luminal speeds is far heavier than the spacecraft itself, resulting in an unacceptably high payload ratio. Using gamma-ray jets, generated by the annihilation of matter and antimatter, with exhaust velocities approaching the speed of light, as spacecraft propulsion is the best option. However, because the thrust generated by gamma-ray jets is too weak, sky-based civilizations often choose to reduce the exhaust velocity at the expense of adding additional propellant and increasing the mass flow rate during the antimatter annihilation process. For example, by mixing in large amounts of metastable metallic hydrogen, the exhaust velocity is reduced to around 0.7 to 0.8 times the speed of light, enabling the spacecraft to achieve high accelerations exceeding 3g, enabling it to accelerate to a maximum speed of 240000 km/s, or 0.8 times the speed of light, over the shortest distance.

The interstellar antimatter-driven spacecraft built by the Sky Star civilization during this period are often very large in size. These stellar-class spacecraft often have a long axis of more than 100 kilometers, an energy output of tens of Yowatts, and a total mass of more than tens of billions of tons. The gamma-ray jets generated during the high-power propulsion of the spacecraft's engine can often reach hundreds of thousands of kilometers. The violent gamma-ray jets are even enough to completely incinerate any planet within the impact range. For safety reasons, these spacecraft have been programmed with instructions that they must never start their own matter-antimatter annihilation gamma-ray jet engines near any habitable planet.

The upper limit of any propulsion method based on the principle of fusion is the speed of light in vacuum, but the upper limit feasible in engineering is less than 30% of the speed of light in vacuum, and the upper limit feasible in military is basically less than 10% of the speed of light in vacuum.

Using controlled or uncontrolled nuclear fusion to propel spacecraft to sub-light speeds requires a lot of nuclear fuel.

代达罗斯计划设想的核聚变推进器的尾气喷出速度可以达到真空光速的7%，将代达罗斯飞船加速到真空光速的0.2%需要的燃料载荷比是0.029。如果飞船满载的燃料量要求能从静止加速到真空光速的0.2%再减速到静止、至少反复10次，则最终燃料载荷比约为0.77，即燃料以外的部分质量为10万吨的飞船要能携带7.7万吨核燃料。

If this thruster is used to reach 15% of the speed of light in a vacuum, the fuel-to-load ratio is approximately 8.664. This fuel quantity significantly exceeds the payload, which is acceptable for an unmanned scientific research vehicle that does not require deceleration, but extremely inefficient for a manned spacecraft or warship.

If this thruster is to be used to reach 90% of the speed of light in a vacuum, the fuel load ratio will exceed 1.3 billion, which is directly declared impossible in engineering terms.

Therefore, if you want to exceed the threshold of 15% of the speed of light, you should just use the antimatter propulsion engine. At present, the theoretical speed of the antimatter engine is about 0.7 times the speed of light. At this speed, the relativistic effect will cause the time flow of the spacecraft reference frame to slow down compared to the starting point, but it will not be particularly obvious. A more representative example is that Avatar's Venture Star spacecraft flew for five years in the time reference frame of the Earth to Pandora, but from the perspective of the Earth and Pandora, the Venture Star flew in space for six years. At 0.7 times the speed of light, due to the relativistic effect, the time flow of the spacecraft slowed down.

Chapter 122: A Utopia of Per Capita Material and Energy Surplus? (6000 words)

"It seems... a little different from what I thought..." Luo Ying murmured softly as she stroked the silver-white shell of the spaceship in front of her. At this moment, Luo Ying and Elena were standing next to a huge dome-shaped building. This dome-shaped building was the Sky Star Aerospace History Museum located above the orbital star ring. This museum houses a very comprehensive series of exhibits, ranging from early spacecraft used in space exploration on Sky Star to today's most advanced spacecraft models.

"Oh, what exactly is the difference?" Elena asked curiously as she looked at Luo Ying who was looking up and down at the spaceship on the booth in front of her.