And Yun Xi rashly summoned Cao Zheng to the palace for an audience, and there were also problems. If he was just an ordinary hundred, the minister would not care even if he didn't understand; But he is the son of Cao Xing, and Yun Xi's unprovoked summons is likely to cause a lot of speculation among the ministers and lead to political struggles. Even if Cao Zheng went back and told others that the emperor had summoned him to chat with others, others would not believe it.

As a result, Yoon-hee had planned to visit his guard one day, and at the same time, seemingly unintentionally, asked him about astronomy to determine if he was really studying astronomy.

But just now, Yun Xi had already determined that Cao Zheng was indeed really studying astronomy. It is of philosophical significance to care why the sun, moon and stars do not fall and to study the laws of their motion, but it is of no philosophical significance to study why they move the way they do.

What's more, Yun Xi also found another person who was also keen on astronomy. Since Zhou Wei was able to meet Cao Zheng at first sight, it means that Zhou Wei could not study astronomy for philosophical purposes.

So Yun Xi suddenly found two people who could become astronomers, or even more so the founders of modern Chinese science, how could he be unhappy?

After a long time, Song Qingshu, the guard standing beside Yun Xi, had to lean down and whisper: "Your Majesty, even if Your Majesty wants to punish Cao Zheng and Zhou Wei, you don't have to let them kneel for so long. ”

"Ahh Yun Xi Muran, who was immersed in his own thoughts, was awakened, and reacted and said, "You two get up." ”

Cao Zheng and Zhou Wei stood up uneasily. Just now, the emperor made the two of them kneel for such a long time, and he didn't know how to punish them. 'Isn't it not only to dismiss me from my position as a hundred households, but also to go to prison? Cao Zheng thought.

But Yunxi's next words were beyond their expectations. "I will not punish you both."

Cao Zheng and Zhou Wei couldn't help but glance at each other. Why is the emperor so tolerant of them?

"I won't punish you for this, and I'm not giving preferential treatment to the two of you," Yun Xi, who saw what the two of them were thinking, said: "Since ancient times, the reason why all dynasties and dynasties have forbidden people to study astronomy is because they think that they can judge good fortune and bad fortune with astrology and know the general trend of the world. But I couldn't be more wrong with that. ”

"If you can avoid disasters and know good fortune by studying astronomy, then how can Meng Yuan perish? He could have known where someone was about to rebel through Qin Tianjian watching the stars at night, so he could kill that person in advance, wouldn't it be fine? ”

"In the same way, it can be seen that if you can really know the general trend of the world by watching the stars at night, then in the Song Dynasty, after Yan Agu raised the army, he should know that it should be a big trouble in the future, and he will not join forces with him to destroy Liao and ruin the country."

"From this, we can know that astronomy is astronomy, and astronomy is astronomy, and we can formulate a calendar according to it, and know what season there will be a southeast wind and what season will have a northwest wind, but we can't know the good fortune and misfortune and the general trend of the world."

Yun Xi must break the rule that prohibits the study of astronomy among the people. As the origin of modern science, how can astronomy be developed if it cannot be dismantled? If astronomy could not develop, geology, mechanics, and geometry would not be able to develop, and the science of the Ming Dynasty would always lag behind until it was knocked on by outsiders.

"Secretary Qing, after I return to the palace, I will announce that from tomorrow onwards, the system of strictly prohibiting the practice of astronomy and astronomy set by the emperor in the "Da Ming Law" will be abolished." Yun Xi instructed Song Qingshu again.

Cao Zheng and Zhou Wei suddenly became excited. The two of them because Zhu Yuanzhang strictly forbade the study of astronomy and astronomy, and killed a lot of people because of this, so they can only study secretly, but if they are found by their families, it is a good fight, and now the emperor actually wants to abolish the regulations prohibiting the study of astronomy, and they finally don't have to hide in the future.

"Ministers (students) thank you for Your Majesty Longen." The two of them knelt down again and said.

"Flat." Yun Xi said.

After they stood up, Yun Xi sat the two of them down and asked, "I am also interested in astronomy, I wonder how you are studying now?" Maybe we can talk to me. ”

"Your Majesty, the minister has carefully studied astronomy and astronomy, and there is something incomprehensible. Gai Tian said that there are many omissions that can be falsified, so don't care about it; But there are also many problems with Hun Tianshuo. ”

Cao Zheng said: "If the sun and moon are attached to the celestial sphere, then why is there a solar eclipse? A solar eclipse is caused by the occultation of the moon, and the occultation of the moon means that the moon is under the sun. If the moon is under the sun, the moon will not be attached to the celestial sphere, which is contrary to the theory of the heavens. ”

But if there is no celestial sphere as the clouds say in the sky, how can the sun, moon and stars rise in the east and set in the west in unison? This is the first minister who can't understand. ”

'Huh? Hasn't Chinese astronomy put forward a multi-celestial theory? Yun Xi was a little surprised. He had not previously communicated with anyone else about astronomy, so he did not know how astronomical theory was developing at this time.

Yun Xi opened his mouth to mention his multi-heavenly layer theory, but opened his mouth and swallowed back the words. If Qin Tianjian already had a multi-heavenly layer theory at this time, then it would not be good for him to say it as an original. "It would be nice if there was an official from Qin Tianjian at this time." He muttered under his breath.

But at this moment, Li Bo suddenly whispered in Yun Xi's ear: "Your Majesty, the minister just saw that Si Chengtang, the deputy superintendent of Qintian, was walking on the street outside the inn. Li Bo happened to be standing next to the window just now, and with a glance of his eyes, he saw Si Chengtang walking on the street. It happened that he heard Yun Xi muttering softly again, so he leaned into his ear and said this,

"Sichengtang?" Yun Xi was overjoyed, this was really a pillow when he was sleepy: "Bring him up quickly." ”

Li Bo took the order. After a while, he pulled a middle-aged man in his forties to come up, and when the man saw Yun Xi, he immediately knelt down and said, "Chenqin Heavenly Prison Deputy Sicheng Tang has seen Your Majesty. ”

Si Chengtang knelt on the ground with some trepidation. This year, he has a nephew who was admitted to the Jinshi, although he is only a third-class Jinshi, and it makes their family happy, so he went home to celebrate today, but he didn't want to be discovered by the emperor on the way. "The emperor didn't call me because of this." He thought.

Yun Xi didn't expect him to appear here at this time, it should be reflected before the time comes. He didn't pay attention to him, and said to Cao Zheng without turning his head: "You will repeat what you just said to Deputy Si Jian again." ”

Cao Zheng immediately repeated it. Yun Xi turned his head to Si Chengtang and said, "Can you hear clearly?" This question may be answered? ”

"Your Majesty, there is no explanation for this matter. However, in the former Yuan Dynasty, there was a man from Persia named Zamaruddin, who came to the Central Plains during the reign of Meng Ge, and Yuan Shizu was called the emperor and joined Si Tiantai. ”

"This man once said that hundreds of years ago, there were celestial people who deduced that the heavens were divided into eleven layers, namely the lunar sky, the Mercury sky, the Venus sky, the solar day, the Martian sky, the Jupiter sky, the Saturn sky, the sidereal sky, the crystal sky, the highest heaven and the pure fire day, as the name suggests, each layer of heaven is wrapped with a sun, moon or star."

As to why the rotation of the sun, moon and stars around the earth is not circular, he thought that all the sun, moon and stars were constantly moving around a smaller circle, the center of which and the center of each circle moved around the circle centered on the earth. The circle that this person circles around the earth is called the Uniform Wheel, and the Minor Circle is called the Present Wheel. And it is said that the earth is not in the middle of the chakra, but slightly deviated. The five stars of the sun and the moon move upwards as they do, and they also revolve around the earth once a day together with the stars. ”

"In the pre-Yuan period, there were people from Han and Mongolia who thought about this, so it was difficult to confirm whether it was true or not, so Qin Tianjian didn't care about it."

Si Chengtang answered in great detail about the theory of multi-heavenly layers.

Yun Xi heard this and said to Cao Zheng: "Do you understand? ”

"I understand." This point of view was clearer than all the opinions he had known before, and it was like a long drought and a rain in a long drought to him, so Cao Zheng scratched his ears and cheeks with joy, and wanted to record these words immediately. Not only him, but also Zhou Wei.

Yun Xi didn't feel good in his heart. Obviously, there were theories to explain the phenomenon of solar eclipses before, but only the people of Qin Tianjian knew about it, and no one else knew that even if there were one or two people like Cao Zheng who liked astronomy and were not afraid of being arrested and killed, it was impossible to deduce astronomical theories from scratch, and many of Qin Tianjian's theories were not studied, resulting in the stagnation of Chinese astronomy. 'It is necessary to change the system of the Qin Heavenly Prison. He thought to himself.

After a while, Yun Xi came back to his senses, and when he saw Cao Zheng behaving like this, he smiled and instructed Song Qingshu, "Do you bring pen and paper?" If you bring it, take it out to Cao Aiqing and Zhou Jinshi. ”

Of course, Song Qingshu brought pen and paper with him. Yun Xi often has some unusual ideas to write down, so there will always be people who follow Yun Xi with pen and paper. There were no eunuchs coming out today, so Song Qingshu took it. At this time, he took out the blank paper and pencil and handed them to Cao Zheng and Zhou Wei.

The two of them took the pencil and were not surprised, and wrote on the white paper. It has been two years since the invention of the pencil, and although it is still difficult to see it locally, it has been widely used in Beijing because of the convenience of writing, and it is sold in many places.

When the two of them stopped writing, Yun Xi asked again, "Do you two have any other doubts?" ”

"Your Majesty," Zhou Wei said, "the students still have doubts. ”

"The student just heard the multi-heavenly theory, which is indeed better than the Hun Tian theory, but the student has another doubt."

"If, according to the theory of the heavens, all the sun, moon and stars are set on the same celestial sphere, then it is very clear that all the stars go around the earth in one day. But if there are multiple heavenly layers or celestial spheres, then how can these many suns, moons, and stars go around the earth exactly once in one day? ”

Although Zhou Wei had just heard this theory, he immediately grasped the core question of the multi-celestial theory: why can the sun, moon and many stars circle the earth in the same amount of time?

Of course, the ancient Greek scholars who first proposed the theory of multi-celestial layers also wondered about this problem, and later proposed the theory of the small wheel, that is, there is a small wheel that revolves around the wheel, and the motion of the planets is affected by the small wheel. However, this led to the complexity of this astronomical system, and some planets had as many as 80 auxiliary wheels, which could not be calculated at all, and finally Copernicus proposed the only correct answer: the earth rotates in one day, not the sun, moon and stars revolving around the earth.

However, Yun Xi looked at Si Cheng Tang. He wondered if China had any ideas that could be reasonably explained at this time.

However, as expected, Si Chengtang thought for a long time and said to Yun Xi: "Your Majesty, the minister has never heard of a statement that can explain this issue. "Although Si Chengtang has no pressure to work in the Qin Tianjian, he is still more conscientious, and he has read all the books on astronomical and astronomical theories kept in the Qin Tianjian, but he does not remember seeing any statements that can explain this problem. If so, he should be impressed, even if he can't remember everything.

Yun Xi turned his head to look at Cao Zheng in front of him, and then turned to look at the floor, silent. He was wondering whether to talk about the concept of the Earth's rotation.

It is very simple to put forward a concept or theory, but Yun Xi wants more than just a theory, a single very correct and world-leading theory does not mean much to him or the Ming Dynasty, what he wants is a scientific method. In short, it is necessary to be able to support the proposed theory with mathematical models and corroborate them with actual observed astronomical phenomena. And that's not something Yoon-hee can propose.

The reason why the ancients denied the rotation of the earth was because they could not explain why the arrows shot at the sky directly above would end up in the same place on the ground. This point of view is well explained because of inertia. Even if Yunxi can't answer the inertia question perfectly, at least he can fool the past.

But the doctrine of rotation has a premise, which is that the earth is a sphere by default. And this is something that Yunxi can't explain.

In ancient China, no one had ever put forward the theory of the circle of the earth. But the people who came up with the Earth Circle theory face a huge problem: why don't people living on the other side of the planet fall? Even if there is no one on the other side, the Earth Circle Theory also means that except for a very few people, the rest of the people are not directly above the enemy and should stand crookedly, but in fact, everyone will not stand like this when they stand, so in the end, the Earth Circle Theory is denied.

The ancient Greeks around the time of the Common Era, after putting forward the theory of the circle of the earth, put forward a point of view on why people who thought that it was very common and did not need to explain why people stood on the ground: gravity or gravity (not gravitational force), the reason why people can stand on the ground is because of gravity, and pointed out that the direction of gravity is not vertical downward, but pointing to the center of the earth, which solves the biggest problem of the theory of the circle of the earth, makes the theory of the circle of the earth become the mainstream theory under the condition that it cannot be confirmed at all, and lays the foundation of the theory of the center of the earth.

Yunxi knows the theory of gravity, but he doesn't know how the theory of gravity is proposed, let alone prove the correctness of the theory of gravity. This is a complex mathematical problem, and no one who specializes in this knows about it, so even if he says the gravity theory to the few people in front of him, it doesn't make much sense.