Before mastering the elemental decay technology, whether it was the nuclear fusion that Xiao Yu mainly uses now, or the nuclear fission that Xiao Yu eliminated, there are quite strict requirements for fuel, such as nuclear fusion, which requires that the fuel must be hydrogen, and nuclear fission requires that the fuel must be uranium, plutonium and other heavy elements.

But elemental decay has no requirement for this. Any element can be used as fuel, that is, even the lightest element, hydrogen, can be used as fuel for elemental decay, but it is less efficient.

This means that during the long space voyage, when Xiao Yu is short of fuel, Xiao Yu can even directly dismantle the spacecraft and use its materials as fuel. The best part is that because of this property of elemental decay, its fuel can be recycled. For example, a kilogram of iron is decayed into 500 grams of hydrogen, and these 500 grams of hydrogen can still be used as fuel, so that Xiao Yu can even convert the entire mass of the substance into energy for his own use.

In this way, the total efficiency of elemental decay is not much different from the efficiency of positive and antimatter annihilation. It's just that the energy release process of positive and antimatter annihilation is more violent, and the elemental decay is relatively gentle. In Xiao Yu's planning, the positive and antimatter annihilation technology developed in the future will coexist with the elemental decay technology, the positive and antimatter annihilation will be mainly used for weapon manufacturing and some instruments that require more energy per unit of time, and the elemental decay technology will be mainly used for conventional power.

These two different ways of obtaining energy will coexist on top of Xiao Yu's spaceship, each with different tasks.

At this stage, Xiao Yu's development of elemental decay jishu is still in the laboratory stage, but its jishu content is lower than that of antimatter manufacturing, and it is expected to achieve large-scale application within a few hundred years.

At that time, the problem of insufficient power for faster-than-light navigation will be solved. On the basis of the elemental decay jishu, Xiao Yu is expected to achieve the long-awaited faster-than-light voyage jishu.

In the silence of the universe, Xiao Yu's fleet was speeding towards the aging star in the distance.

The star has fallen into the aging stage, and its mass is about 1.9 times that of the sun, which is not enough to support a supernova explosion, and it will end its life in a relatively gentle way.

It has turned into a red giant. Because of the diffusion of the outer substance, its surface temperature begins to decrease, hence its red color. It has a lot of volume. The radius even reaches 60 million kilometers, which is dozens of times that of the sun. If placed in the position of the Sun, it will directly swallow Mercury, approach Venus, and turn the Earth's surface into purgatory.

Xiao Yu knows. Billions of years from now, the sun will be the end of this chill.

In advance observations. Xiao Yu did not find any signs of planets around this star. But Xiao Yu wasn't too worried. Because not being able to see does not mean that there is no planet, there is a high probability that the luminosity of the star is too strong, obscuring the trace of the planet's existence. Besides, it doesn't matter if the planet doesn't exist, as long as there is an asteroid belt. Or a slightly decent asteroid, which is enough for Xiao Yu to use.

Any asteroid with a diameter of more than 10 kilometers has a mass of up to hundreds of billions of tons.

During the long journey, Xiao Yu was conducting intense research at the same time. Close observation of the surrounding stars is still underway. Xiao Yu believed that the war between Taihao and the Sweeper civilization would at least be a stellar-level cataclysm, which would affect all beings around the battlefield. At that time, there will inevitably be some unusual signs, such as the sudden explosion of stars, a sudden increase in brightness, X-rays from unknown sources, gamma-ray bursts, etc., that is to say, above Xiao Yu's current position, Xiao Yu can also detect a little clue of this war.

This bit of information has no effect on the current Xiao Yu, but after Xiao Yu's technology develops to a certain extent, Xiao Yu will be able to use this information to analyze the true combat power of the Sweeper civilization.

Time, in the boundless silence, slowly slipped away.

After one hundred and fifty years of sailing, more than three hundred years of real time, Xiao Yu arrived next to this red giant star.

The current distance is nearly 30 billion kilometers.

Because the star is aging, growing in size, and stellar activity is becoming more intense, its stellar circle is much larger than that of the Sun. Above this distance, it has entered its heliopause.

This is the world of this aging star.

What caught Xiao Yu's eyes was a star as bright as the full moon on the earth. If you look at the Sun from this distance, the brightness of the Sun will be thousands of times dimmer than it, about the level of a bright star.

Xiao Yu has already launched thousands of satellites, intending to explore the shili range of this star. But the results of the investigation disappointed Xiao Yu.

"It'...... It doesn't have any planets, not even the asteroid belt? How many asteroids are there? Faced with this result, Xiao Yu felt a little incredible.

Under the exploration of thousands of satellites, the shili range of this star was unobstructed in front of Xiao Yu. After some searching, Xiao Yu not only did not find a big planet, but also a few small asteroids. Not to mention comets and the like, you can't see the shadows.

Only a few asteroids with a diameter of not even more than 10 meters have been discovered, slowly orbiting this star.

"It's incredible, it's basically impossible for such a scenario to happen on top of the stars in the inner river system. Maybe...... Is it because the material around the river system is already thin? ”

Xiao Yu thought slowly, slowly shrinking the distance from the star.

If it was possible, Xiao Yu really didn't want to get too close to this aging and crazy star. But there is no way, outside of this star, the nearest star is more than two hundred light years away, and Xiao Yu's fuel at this moment is really not enough to support him to start such a long voyage.

Then, entrenching around this star becomes the only option. After all, there is always some residual material around the stars, and at worst, there is still solar energy to use. Without this star, there is really nothing.

After thinking about it like this, Xiao Yu made up his mind to stay around this star for a while. Once you've mastered elemental decay technology and faster-than-light travel technology, it's not too late to leave.

At that time, Xiao Yu will be able to obtain sufficient fuel by dismantling the spacecraft, and the voyage of hundreds of light years will no longer be an insurmountable long distance for Xiao Yu.

"Matter, it's really too thin. However, since stars can be formed, it proves that there was once enough material here, and there are no large planets to explain, and there are not even asteroids, which is really unreasonable. Xiao Yu thought slowly.

"It was supposed to have formed within the river system, and then it was thrown to where it is now during a long gravitational engagement. It may be that during the long journey, its planets, or interstellar matter, were captured by the rest of the stars. But that's still not enough to explain why its interstellar space material is so thin. ”

Xiao Yu was thinking as he approached the star at a speed of about 100 kilometers per second.

At this speed, invisible interstellar dust continued to hit Xiao Yu's spaceship, and a trace amount of X-rays were emitted, and at the same time, Xiao Yu detected that his fleet was being slowed down.

After seeing this phenomenon, Xiao Yu suddenly realized.

"I see...... The star's stellar material is ejected, causing the entire galaxy to be filled with dense interstellar matter, and under the constant impact, the orbital speed of the planets orbiting around it, or asteroids, will gradually slow down, lose momentum, and then slowly approach the star, and finally be swallowed by it......"

"It turned out that the stars orbiting around it were not captured by the rest of the stars, but eaten by himself......"

"It's so unfortunate that you've eaten all the material and left me nothing." Xiao Yu sighed in his heart.

In this star system, the concentration of interstellar dust is very high, but this is only compared with interstellar space, in fact, the space here is not an exaggeration to say that it is a vacuum. It is basically impossible to rely on collecting interstellar dust to obtain enough material.

In other words, in the next period of time, except for stellar energy, Xiao Yu basically could not get the rest of the material supplement.

"It's better to have than nothing, and a little bit counts." Xiao Yu pondered, slowly slowing down his speed, until about ten kilometers per second, adjusted his orbit to orbit around the star.

It's about two billion kilometers away, and here, it's much brighter than the sun, and it's like a huge fireball hanging in the darkness of space.

After entering the stable orbit, Xiao Yu began his work.

Xiao Yu first built a batch of stellar energy collection instruments to save his own fuel as much as possible, and then took out the various parts of the large particle collider and rearranged them around the star for his own research.

"This time, we must study the elemental decay jishu and the faster-than-light travel jishu." Xiao Yu secretly made up his mind.

At this moment, Xiao Yu suddenly received a message.

This message is still sent in the form of space broadcasting. It entered Xiao Yu's mind and was immediately automatically translated into a language that Xiao Yu could understand.

From this information, Xiao Yu sensed a little familiarity.

"Guardian Civilization! I am a Taihao civilization from the Big Magellanic system, and I am fighting your old enemy, come to the galaxy Orion Cantilevertail to help me! (To be continued......)

PS: The second update is coming, I'm going to hurry up and write the third update...... Hey, ask for a monthly pass weakly...... The ones behind are catching up......