Not long after the expeditionary fleet returned to Earth.

The Supreme Council of Mankind has launched a secret plan.

Some students of the military scientific research class, as well as scientists from scientific research departments such as the Academy of Military Sciences, participated.

Among them, Lang Xiaonian is the leader of the military scientific research team.

"With such an important task as opening a mine, why is Xiao Siyan the person in charge? I'm not convinced! As soon as Niu Dazhi heard that he wanted to listen to Lang Xiaonian's arrangement, he was immediately unconvinced.

"Xiao Nian, let's kick him out of the secret plan team." Eve encouraged.

"Brother Dazhi, this secret plan is related to astronomy, I am the representative of the class, and my father is in charge of the Academy of Military Sciences, so it is more convenient to contact." Lang Xiaonian explained.

When Niu Dazhi heard this, he laughed, patted Lang Xiaonian on the shoulder and said, "Xiaonian, I am absolutely confident in your attainments in astronomy, I am optimistic about you, do a good job." ”

He had just finished speaking when he was suddenly hit by a hand batter flying out and hitting the wall.

"Sit down, the professor is ready to share 10% of the computing power to participate in the discussion of this secret plan." Fang Yuan slapped Fei Niu Dazhi and asked everyone to sit down, officially starting the first meeting of this secret plan.

The meeting begins.

Admiral Rhodes and Fang Zhenguo came to power at the same time.

Admiral Rhodes is a representative of the Supreme Council, and Fang Zhenguo, a representative of the East China Sea Headquarters, announced the plan together: "Bringing everyone together here is to start a project, 'Second Home'.

"According to the report of the Planetary Defense Crisis Prevention and Analysis Group, the Earth has become the focal planet of the Milky Way and may become the main battlefield of advanced civilizations at any time.

"Therefore, we need another terrestrial planet as a second home, to continue the spark of civilization and nurture our children and grandchildren.

"The first thing in the Second Home plan is the choice of terrestrial planets, what kind of planet we want to choose as the second home of human civilization."

This question is indeed a comprehensive problem in astronomy, biology and other aspects.

The most critical issue is actually the choice of star systems.

Next, Chu Xingyun of the Planetary Defense Staff said: "With the current level of human science and technology, we have the ability to go to a very distant place to build a second home.

"As a result, we have a wide range of star systems to choose from, and the key element is the need to avoid the gaze of higher civilizations.

"We need a second home that will not be discovered by higher civilizations, so the astronomers here today need to find the most suitable star for us."

An astronomy professor raised his hand and asked, "I have a question, with the current observation methods of human beings, outside the solar system, only stars can be observed, but not planets. It's hard to find a terrestrial planet. ”

"This has been discussed within the planning group......"

Chu Xingyun replied: "The planets we need don't have to be the same as the Earth's environment. With the current ability of human beings to transform the environment, the requirements for the planetary environment are not strict.

"According to the planetary data collected by the expeditionary fleet, the probability of a human viable planet in a star system is not low. The relevant astronomical data ꓹ Professor Lang will explain it. ”

Lang Tongguang stood up and took a document and said, "Everyone, when I received this task, I had already done some data collection.

"I started doing astronomy research 30 years ago, when the astronomical community thought that there were 100 billion to 400 billion stars in the Milky Way.

"Yes, we don't know how many stars there are in the Milky Way, because we can't observe most of them."

He paused, and then said, "Let's get to the point, and the issue we want to analyze and discuss today is to find a planet that can become a second home for mankind.

"In fact, the question can change from looking for a terrestrial planet to finding a G-type star.

Why?

"In fact, the so-called need for terrestrial planets is actually the need for a sun-like star.

"Because only G-type stars can meet human requirements for the planetary environment and climate.

"We can't observe planets, but we can observe stars.

"According to research data, what is the probability of a terrestrial planet in a G-type sun-like star system?

The answer is 18 percent, and yes, in a G-type star system, there is an 18 percent chance of a terrestrial planet.

"This means that if you look for a terrestrial planet around a G-type star, you can find a terrestrial planet by looking for an average of 5 or 6 stars.

"The search for terrestrial planets, then, has been transformed into the search for sun-like stars.

"As long as a region is delineated with at least six stars, then there is every hope that human beings will find a second home."

After listening to Lang Tongguang's explanation, things have indeed become much simpler.

"We have a star chart, so isn't that much easier?" One of the participants said.

"No, we can't choose a second home on the star map." Chu Xingyun immediately denied this idea.

"Why?"

"First of all, we got the star map, which is from the Carbon Alliance. Accuracy of the star map, unable to determine ......"

Chu Xingyun explained: "Secondly, this star map is actually a star map from 20,000 years ago, and its timeliness is debatable. Of course, 20,000 years is not much change for the universe, so this star map is still of great value.

"However, humanity must use its own power to update the star map, not blindly rely on the old star map.

"Third, there are only 80 million stars on the star map, while the number of stars in the Milky Way should be more than 200 billion.

In other words, the stars marked on the star map account for only 0.04% of the total number of stars, and the Milky Way is far from complete.

"We should look for a second home for humanity in an unexplored galaxy, a second home that will not be discovered by advanced civilizations."

Next.

Astronomers from all walks of life began to discuss in which star field to choose the second home of mankind.

Military scientific research classes also got together to discuss.

"First of all, exceptionally bright O-type, B-type, A-type, F-type stars can be excluded, eh...... Perhaps the F-type star can be preserved, and the F-type star is up to twice the mass of the Sun......"

Lang Xiaocheng began to discuss with everyone: "Then the M-type star with the smallest mass can also be abandoned, and this kind of star is also difficult to observe, so don't worry about it."

"The main target is on G-type sun-like stars, which have a temperature of around 5,000 K.

"In fact, it is easy to find sun-like stars, but how to make advanced civilizations unable to discover them is the most difficult."

"Actually, it's not difficult, as long as it's far away from the star field of the hyperspace channel, the advanced civilization will basically not get close." Fang Yuan shrugged and said.

This is indeed the case.

The main reason why the solar system was discovered by advanced civilizations is that there is a hyperspace node in the solar system that leads to Tianyuan IV.