Zhang Yuan quickly built a mathematical model: "Think of the Milky Way as a plane, that is, R^2." Consider one of the ships doing a standard Brownian motion, or two ships doing a standard Brownian motion independently.

"When the distance between two spacecraft is less than some small constant, such as 0.01, it is considered to have met."

"Since two-dimensional Brownian motion is a frequent return in the neighborhood, as long as the time is long enough, the two spacecraft will definitely meet."

"Consider two independent criteria for Brownian motion A(t), B(t). A(1)+B(1) and A(2) are co-distributed, because B(2) = B(1)+[B(2)-B(1)], which is also the sum of two independent standard normals. This means that the sum of two independent standard Brownian motions at time t is equal to the distribution of one standard Brownian motion at time 2t. ”

Zhang Yuan frowned and said, "Considering this simple model, the probability of observing an alien civilization in a moving spaceship is twice that of a stationary spaceship. In other words, assuming that we can observe a civilization capable of interstellar voyages in an average of 1,300 years, it will take 2,600 years for the earth's civilization to observe once. ”

Lin Xuanxuan's small mouth opened slightly, this is simply some information generated out of nothing!

She was a little proud in her heart, and secretly sighed that her vision was good.

Soon, Zhang Yuan shook his head, this is just a simple model, plus the sample is too small, the real situation must be very different from the estimate.

"If interstellar civilizations are not so rare, then this universe may be more exciting than we imagined!"

Of course, Zhang Yuan is not the only smart person in the spaceship, and with such a simple encounter, all kinds of ideas have emerged one after another.

The first question: how big is this alien spaceship and where is it going?

According to astronomical observations, it is at least the size of Mercury! And it is moving at 40% of the speed of light, and the faint light is produced because the hull of the ship moving at ultra-high speed collides with trace particles in the universe.

Because of the extremely high sailing speed, the observed image is like a noodle, stretched a little.

The direction of its motion, approximately at an angle of 123 degrees to the direction of movement of the Earth Age, and its destination is unknown, and it is certainly not the Earth or the Gliese 581 anyway.

Seeing this, Zhang Yuan relaxed slightly, anyway, it has nothing to do with their destination.

The second question, the alien spacecraft, has the Earth Age been discovered?

Probably not, the Earth Age is still too small, in the bleak universe, it can be said that you can't see five fingers, and if there is no external electromagnetic radiation, it is difficult to find an object 0.12 light years away.

But the other party once sent a series of short signals, and I don't know whether they were sent in a directional direction or in groups in all directions.

Zhang Yuan clicked on this series of signals, which were about more than 600 bytes, and there were many peaks and troughs that were repeated, indicating that it was an electromagnetic signal of logical significance.

Unfortunately, because the amount of data is so small, it is impossible for people to decipher these alien scripts.

And then there is no then, even if the other party reports good intentions, humans do not dare to make bold observations, let alone write back letters, or scan them with radar. Besides, Earthage's radar can't scan anything 0.12 light-years away.

Zhang Yuan felt a little regretful, there is never a shortage of matter in the universe, and the most precious thing is information. Humans, who have never communicated with interstellar civilizations, missed this time, and they don't know if they will be in the Year of the Monkey next time......

There are many of the same points in the following post.

[The technology of this civilization must be much stronger than ours. 】

[Surely, didn't you see that it was a planetary-level spaceship?] There shouldn't be a way to accelerate this planet to 40% of the speed of light using nuclear fusion......]

[I think it's vacuum zero-point energy, or black hole energy.] Or maybe it's an anti-gravity propulsion device, and we don't seem to see the plasma flame at the ejection. 】

[It would be nice to have a little more observational data......]

After all, I haven't felt the fear of the unknown, in these recent posts, people's minds are really more optimistic and open, and Zhang Yuan is a little itchy in his heart when he sees all kinds of discussions, and he also wants to express some of his own opinions.

"Look at it, confiscate!" Lin Xuanxuan snatched his mobile phone, "That's it for today, the patient has to look like a patient." I don't care what happens to you when you are discharged from the hospital. ”

A week later, Zhang Yuan was officially discharged from the hospital and began his normal work.

He is already a high-level administrator, and as the ship ages, he no longer has a lot of time for himself as he used to.

His work became even busier, and basically once a week, he would organize a manpower to maintain the entire ship.

Moreover, in addition to the alien spaceship that he met by chance, Zhang Yuan also learned about some other stories that have happened in the past few hundred years......

None of them are good.

First of all, the old captain left the ship he loved three years after hibernation.

He was succeeded by Captain Hayashi of the Council of Sciences.

Even if you have experienced this feeling many times, even if you are mentally prepared, it is still not so comfortable.

As soon as you open your eyes and close your eyes, some people have disappeared......

The second thing, unfortunately, since the death of Mr. Aydin on Earth, the spaceship has completely lost contact with Earth.

There is no more great man of the same era.

What happened to the civilization of the earth is already a complete unknown.

Zhang Yuan let out a long sigh and immersed himself in his work......

……

A year passed quickly, sending off one colleague after another, and then it was time to eat a casual meal, and it was time to hibernate again.

The only one who can really accompany him for a long time is Lin Xuanxuan, a life partner.

While eating, Zhang Yuan suddenly felt that it was really good to have someone who had been with him...... Life could have been a little worse without this life partner.

“…… How old are you? Lin Xuanxuan asked.

"Me? Uncle who is over 1,300 years old, what? Zhang Yuan just buried his head in eating.

"Real age!"

“…… 30？ Zhang Yuan calculated carefully, and suddenly found that he was already thirty years old. And it just so happens that today is my birthday. In this environment, it was really a bit difficult to tell the passage of time, and he never had a habit of having a birthday.

"Happy birthday to 30-year-old uncle!" Lin Xuanxuan took out a red apple and handed it to him.

"Thank you for this beautiful young lady...... And your body temperature! Zhang Yuan joked. When you get used to playing and making trouble, you will always have an instinctive sense of randomness, just like a real relative.

(Why are there so many people in the book review area who say that I am water, and one person still posts several articles?) There are simply no words...... ）

(What else is there to ask for a fast-paced, relaxed spirit?) This is not a novice in the first place, and the object of my reading has never been whether it is a novice or not. ）