The last human in the universe

Chapter 155 Secondary Radiation
Zhuang Yunwei's method is actually very simple and can be summed up in just one sentence.

By observing whether there are subatomic particles such as "muons", it is determined whether there are macroscopic substances other than the Yuanhang spacecraft around the Yuanhang spacecraft.Afterwards, through the direction of the muon, determine the approximate orientation of those macroscopic substances, and then use human power to carry out a further careful search for that orientation.

The so-called muon is a basic subatomic particle.Its half-life is only a few microseconds, which means it is extremely unstable.After being produced, it rapidly decays into an electron, an antielectron neutrino, and a muon neutrino.

This characteristic of it determines that it cannot spread too far in the universe.

The energy level required to produce muons is extremely high, neither nuclear fission nor fusion can produce it.Generally speaking, muons can only be produced in equipment in high-energy physics laboratories, such as high-speed particle colliders.

But on the other hand, there are many particles with extremely high energy in the universe itself.Once these particles collide with other particles, they can reach or even exceed the energy level of the particle collider, so that muons will be produced.

Most of the muons observed on the earth are produced by the collision of high-energy cosmic particles into the earth's atmosphere.

This kind of high-energy cosmic particles also widely exists in the interstellar space where the Yuanhang spacecraft is located at the moment.

They either come from a supernova explosion, or from a neutron star merger, collision, or from the jet of black hole devouring matter...

They are everywhere in the universe.

Then in this way, a very interesting thing will happen.

After excluding the muons produced by the cosmic high-energy particles hitting the Yuanhang spacecraft itself, if the remaining muons can still be observed, what does it mean?
Because the muon half-life is too short to travel in the universe for a long time, it can only show that a cosmic high-energy particle collided with the rest of the macroscopic matter not far from the Yuanhang spacecraft, and the newly formed Muons, or called secondary radiation, were observed by people.

——Through the research on the previously obtained materials from that at least four-level super civilization, people have confirmed that muons will also be produced when high-energy particles of the universe collide with it.

The knowledge that Zhao Changxing has mastered let him know that this is the reason why Professor Zhuang Yunwei said before that "if the shell materials of those gravity bombs are similar to those of their spaceships", this method is useful.

Quite simply, if the materials are not similar, it means that cosmic high-energy particles will not necessarily produce muons when they collide with them, so this method is naturally useless.

But that also means another conundrum.

It is still the observation accuracy.

"Can we achieve the accuracy?"

Zhuang Yunwei was silent for a moment, and said: "Theoretically, it can be achieved. But... we need to pay a price. We need to expand the existing neutrino telescopes, and build at least four new neutrino telescopes of this level, Only in this way can there be an acceptable observation probability."

When they were on the earth, in order to observe neutrinos with such strong penetrating power that even the whole sun is like a vacuum for them, people will build as large a neutrino as possible made of ultra-pure water, heavy water and other media. Occupying the container, in order to increase the probability of reacting with neutrinos, and then using Cherenkov radiation, the signal they produce is captured by photomultiplier tubes.

Neutrino telescopes are usually built in extremely deep places underground, mainly to prevent interference from other types of particles.And to measure whether a place is suitable for building a neutrino telescope, there is an indicator called "muon flux".

Because muons also have extremely strong penetrating power, neutrino telescopes built in extremely deep underground will also be disturbed by muons.This makes people very annoying, in order to shield the interference, they have to try to build the neutrino telescope deeper.

This means that the neutrino telescope can also be used to detect muons.The only difference is that in the past, it was necessary to shield the interference of muons as much as possible, but now the center of gravity has been changed, so it is no longer necessary.

Facing Zhuang Yunwei's words, Zhao Changxing once again entered into thinking.

At this moment, the Yuanhang spacecraft is located in the vast interstellar space.The nearest star, Lakai 9352, is also 2.9 light-years away.

It is impossible to get any supplies here.However, the material reserves of the Yuanhang spacecraft are not sufficient.

Especially now, under the premise that almost all previous kinetic energy has been lost.

Whether to expand the existing neutrino telescope and build four new neutrino telescopes of the same level is also a difficult choice for Zhao Changxing.

He knew that this was already the limit of what the scientific and technological strength of human civilization could do at the current stage.It's almost impossible to do it better than this.

On the one hand are gravity bombs that may have extremely high strategic significance for civilization.On the other hand, there are insufficient material reserves and the cruel reality that may cause people to starve.

how to choose?

Except for Zhao Changxing, all civilization leaders asked themselves that they were incapable of making a judgment on the issue of "whether it is really necessary to take the risk of starving people to gamble a probability".

Yes, it's just a probability.

Even if this is done, there is also the possibility of not getting any gravity bombs.Moreover, the energy and materials that have been consumed cannot be recovered.

Except for Zhao Changxing, no one has this kind of vision, no one has such a long-term vision.

Zhao Changxing was not in a hurry to make a decision now.He just asked for all the detailed information about the expansion and renovation plan, and also asked for the material reserve database of the Yuanhang spacecraft, and then began to think carefully.

All are waiting.

Zhao Changxing knew that he couldn't delay for too long.Within five days, at most five days, a decision must be made.

But on the third day, another incident reported by the astronomers broke the calm of the current stage.

Among the pictures observed by the astronomical telescope, Zhao Changxing saw a shocking scene.

It was originally a huge, red hot star.It has about half the mass of the sun, and around it, several planets revolve around it.

It was a self-contained star world, just like the original solar system.

The astronomical telescope captured its image clearly.Even if the distance is several light-years away, its light still makes people feel a little dazzling in the picture.

It's so huge, so powerful.

but……

The next moment, Zhao Changxing saw a shadow sweeping from the lower left corner of the screen, like a solar eclipse, beginning to obscure the light of the star.

Zhao Changxing watched helplessly as it was covered in half like the moon, and then slowly turned into a "crescent moon", before finally disappearing completely.

After a solar eclipse, stars will also appear.But this time, the massive star never appeared again.

The results of astronomical observations tell people that in that direction, the star can no longer be seen.It, it seemed to be swallowed up by that piece of "black mist".

"It's black mist again!"

At this moment, people couldn't help but think of the scene they saw from the projector screen in the wreckage.

The boundless black mist swept in, and many battleships that were so powerful that one could destroy the entire human civilization, even the Moyun Litar civilization, turned into wrecks without even the power to fight back.I don't know how long he drifted in the universe before being met by people by coincidence.

People don't know if these two "black mist" are the same thing, but at least, they look alike.

Now, it devours a star.

This star is known as Lalande 21185.Yes, it is the star where the main body of the Moyun Litar civilization was located.

At this moment, Viragash and other original Moyunlitars trembled all over, their faces, tentacles, and feet were covered with large patches of dark yellow.

They have been terrified to the extreme.

Because everyone can see that this is not a natural phenomenon.In other words, the probability of being a natural phenomenon is extremely low and can be ignored.

If it is not a natural phenomenon, then nature is man-made.A reasonable explanation is that a certain super civilization arrived there and devoured the star through an unknown way of "black fog".

So... what about the Moyun Litar civilization?
"Is the Moyun Litar civilization destroyed just like this, quietly?"

A civilization leader murmured, with a very complicated expression on his face.

It's lucky, but it doesn't look like it.Although people started this interstellar voyage just to avoid the pursuit of the Moyun Litar civilization.

It's not like it's fear.Although this kind of god-like power is indeed worthy of people's fear.

His expression was more like bewildered.

The universe is so vast.The super civilization is so powerful, but the human civilization is so weak.

What is the next step?
Zhao Changxing said in a low voice: "Based on the time, the Moyun Litar civilization should have not left the Laland 21185 galaxy at this moment. They have been destroyed with a high probability at this moment. All the arrangements we left in the solar system have been done. It's useless."

The progress of the black hole swallowing the sun has accelerated.But at the same time, without the arrival of the Moyun Litar civilization, without their resource exploitation, it is not certain which is better.

"The solar system is too close to that unknown existence, we can't go back, we still have to escape." Zhao Changxing's voice was still calm and firm: "The original plan remains the same. But at this moment, I think, there should be no objection Are there any plans to improve our strength?

So, build new neutrino telescopes. "

(End of this chapter)