Chapter 41: Popular Science Expert, Artificial Rain

"Hehe... Changle, the heaven and earth we are in can be called Earth."

"If we keep walking east, without any deviation in direction, we will eventually return to Furong Garden."

As Su Liang's words fell, Changle had already opened her mouth wide, looking at Su Liang in disbelief.

This... this was too fantastical.

To prove to Changle that the Earth was round, Su Liang immediately gave an example: "Changle, if the ground is flat, why is it that the further a large ship sails at sea, the less you can see the lower part of the ship?"

Although Changle hadn't seen the sea at this time, it had long been recorded in books.

Regarding what Su Liang said, Changle also knew it, and for a moment, she couldn't refute it.

Seeing that Changle couldn't speak at this moment, Su Liang immediately touched her head and said: "Alright, don't overthink it. Could your husband lie to you? If there is a chance in the future, your husband will definitely take you all around the Earth."

Actually, the ancients at this time already had a certain understanding of heaven and earth.

Before the Tang Dynasty, there were already theories of "Gaitian" (Canopy Heaven) and "Huntian" (Celestial Sphere).

According to the "Book of Jin: Treatise on Astronomy," the Gaitian theory states: "It is said that heaven is like a canopy, and earth is like a plate. Both heaven and earth are high in the middle and low on the outside. Below the North Pole is the center of heaven and earth, where the land is highest, and it slopes down in four directions..."

The Gaitian theory appeared as early as the Western Zhou Dynasty. At that time, it was believed that heaven was noble and earth was humble, heaven was round and earth was square, and it was believed that "heaven is round like a canopy, and earth is square like a chessboard," with a dome-shaped heaven covering a square, flat earth.

This was the prototype of the Gaitian theory.

Later, during the development process, there were several different views. Because the round canopy-shaped heaven could not match the edges of the square earth, some people proposed that heaven did not connect with the earth, but hung high above the earth like a large umbrella, with eight pillars supporting the edges of the earth, and the shape of heaven and earth was like a pavilion with a dome-shaped top.

The myths of Gonggong angrily hitting Mount Buzhou and Nüwa patching the sky were based on this.

By the Warring States period, doubts began to arise about the above-mentioned Gaitian theory, so it was modified to "heaven is like a canopy, and earth is like a plate," meaning that heaven is dome-shaped and earth is also dome-shaped, and it was believed that the North Pole was located in the center of the celestial dome, with the sun, moon, and stars rotating around it endlessly.

By the Western Han Dynasty, some people still insisted on this view. The "Zhoubi Suanjing," written at that time, was a representative work of the Gaitian theory.

The Gaitian theory usually explained the appearance and disappearance of the sun, moon, and stars as changes in distance during their operation; when they were far away, they couldn't be seen, and when they were close, they could be seen shining. This explanation was relatively far-fetched, and the Gaitian theory was denied by more and more astronomical observation facts.

Yang Xiong of the Western Han Dynasty proposed the "Eight Difficulties of Gaitian," denying the Gaitian theory.

However, the Gaitian theory still had a certain influence in ancient China. The dome theory proposed by Yu Song of the Jin Dynasty was a continuation and development of the Gaitian theory. During the Northern and Southern Dynasties, the theory of the integration of Huntian and Gaitian also appeared.

The Huntian theory was another cosmic theory in ancient China.

Huntian refers to the fact that heaven is spherical. Some compared it to a large bird egg, some to a large chicken egg, and others to a large pellet. This cosmic theory sprouted during the Warring States period.

In the 4th century BC, the thinker Shen Dao of the Zhao state said: Heaven is not hemispherical, but like a pellet, a complete sphere.

However, he did not mention the shape of the earth.

The first person to guess that the earth was spherical was Hui Shi, a person from the Song state during the Warring States period.

Hui Shi once said: The spherical earth, although limited in volume, can be traveled around endlessly if one keeps walking south. Hui Shi not only believed that the earth was spherical but also that heaven was spherical.

Influenced by this thought, during the reign of Emperor Wu of Han, there was a folk astronomer named Luo Xiahong in Sichuan who made a spherical Huntian instrument to demonstrate celestial phenomena.

Although Luo Xiahong's Huntian instrument was still simple, it was the earliest known Huntian instrument.

It is said that when the Huntian instrument was first made, many people didn't believe it could be of any use. However, when Luo Xiahong demonstrated the Huntian instrument in the basement, people were surprised to find that the constellations marked on the Huntian instrument matched the actual celestial phenomena.

As a result, Luo Xiahong became famous, and the Huntian instrument became widely known.

After Luo Xiahong, Xianyu Wangren, Geng Chengxiang, Zhang Heng, and others developed the theory of the Huntian theory.

Especially Zhang Heng, who made a comprehensive summary of the Huntian theory, making the Huntian theory finally become a very influential cosmic structure system.

In his book "Notes on the Huntian Instrument," Zhang Heng expounded his point of view: "The Huntian is like a chicken egg. The celestial body is round like a pellet, and the earth is like the yolk of a chicken, living alone inside. Heaven is large and earth is small. There is water inside and outside heaven. Heaven wraps the earth, just like a shell wraps the yolk. Heaven and earth each stand on Qi and float on water."

Zhang Heng not only systematically explained the Huntian theory in theory but also made a "Water-Powered Huntian Instrument" on the basis of predecessors' experience to vividly express his Huntian thoughts.

Obviously, this "Huntian theory" cosmic theory represented by Zhang Heng had made great progress compared to the "Gaitian theory" cosmic theory.

It recognized that the Earth was spherical, and based on this theory, it could also explain phenomena such as solar and lunar eclipses, and could predict the dates and times of solar and lunar eclipses.

Precisely because of the progressiveness of the Huntian theory, after it sprouted, it was quickly accepted by astronomers and became the most far-reaching cosmic theory in traditional Chinese culture. For more than a thousand years from the Han Dynasty to the Ming Dynasty, it occupied a dominant position in the astronomical community.

It should be said that the Huntian theory was far closer to the reality of the cosmic structure than the Gaitian theory, but it also had obvious shortcomings.

For example, it regarded the Earth as the center of heaven and earth, which was obviously limited.

In addition, some statements of the Huntian theory could not be explained.

Take the sentence "Heaven and earth each stand on Qi and float on water" for example; when the sun, moon, and stars attached to the inner wall of the celestial sphere and rotating around the earth with the celestial sphere rotate below the horizon, how do they pass through the water?

It must be said that the ancients were quite wise. Comparing the entire Earth to a chicken egg, with heaven as the egg white and earth as the egg yolk, was indeed reasonable.

It was just that regarding the Earth as the center of the entire universe was too limited.

After a night of hard work, Su Liang also made the globe.

The next morning, Su Liang also asked people to invite Li Er and the others over to give them a good popular science lesson.

After everyone arrived at Furong Garden, Su Liang took out the globe.

Not only that, Su Liang also depicted the solar system. Everyone was puzzled upon seeing this. The "Huntian theory" already had corresponding theories. Now that Su Liang depicted the world map on a sphere, it was indisputable, and they also believed in Su Liang.

But facing the "Solar System" drawing Su Liang took out, everyone didn't understand what Su Liang meant.

Su Liang looked at everyone's puzzled gazes and explained: "Hehe... I think everyone also knows the theory of the Huntian theory."

"The Huntian theory is right about one thing: the heaven and earth we are in is indeed a sphere."

"Comparing this entire heaven and earth to a chicken egg, with heaven as the egg white and earth as the egg yolk, is indeed not bad."

Hearing this, everyone nodded one after another. So far, everything Su Liang said was what they knew, just without solid evidence.

They were more concerned about what Su Liang would say next.

"It's just that this heaven and earth... is not the center of the universe," Su Liang said indifferently.

Hearing this, everyone's brows furrowed even tighter. At this moment, they were all staring fixedly at Su Liang, waiting for Su Liang's next words. They had long been accustomed to listening to Su Liang's explanations and firmly believed that Su Liang would definitely give them a reasonable explanation.

"Hehe... does everyone know how day and night come about?" Su Liang asked, looking at everyone.

At this moment, everyone seemed to have remembered something and cast their gazes toward the solar system drawing Su Liang took out.

Everyone then discovered that there were many terms on it, among which terms like Sun, Moon, Earth, etc., were all marked within circles of different sizes.

The one in the very center was clearly the Sun.

Not only that, Su Liang also drew the orbits of the major planets on it, as well as the orbit of the Moon orbiting the Earth.

"Young Master Su, is this Moon marked on your drawing representing the moon?" Fang Xuanling asked.

"Minister Liang is right, it is exactly so!" Su Liang nodded upon hearing this.

He then pointed to the Earth marked on the map and said slowly: "And... the heaven and earth we are in is the Earth."

As Su Liang's words fell, everyone began to observe carefully.

A moment later, Li Er looked at Su Liang and asked: "Son... Son-in-law, do you mean that the Sun is the center of the universe?"

"Uh... you could say that. The Sun is indeed the center of this universe, but it is not the center of the entire universe," Su Liang said lightly.

At this moment, everyone present was dumbfounded and speechless.

What they saw today had overturned their previous understanding. Not only that, what Su Liang meant was that there was an even larger universe; how could they not be shocked?

At this moment, except for Su Liang, only little Sizi was relatively calm; after all, little Sizi was only ten years old now.

Su Liang then asked someone to bring a glass ball, pointing at the solar system map while demonstrating with the glass ball, and said slowly to everyone: "Everyone, the reason why this world has day and night is because the Earth revolves around the Sun."

"At the same time, the Earth itself is also rotating. The Earth rotates once every twelve hours."

"In this way, only half of the Earth can be illuminated by sunlight, so day is formed, and the other half is naturally night."

Everyone understood a little upon hearing this. Although they felt it was incredible, what Su Liang said was indeed more convincing than the "Huntian theory" they had understood before.

At this moment, everyone in the field didn't disturb Su Liang and listened quietly to Su Liang's next words.

"In addition... the reason we can see the moon is because the moon orbits the Earth."

As Su Liang spoke, he demonstrated.

Hearing Su Liang's words, everyone suddenly realized and completely understood why sometimes the moon could be seen during the day.

Afterward, Su Liang also simply explained the reasons for the formation of phenomena such as solar and lunar eclipses.

Everyone listened in a daze, but they had roughly understood the general meaning.

Not only that, Su Liang also simply popularized the reasons for the formation of various weather to everyone, telling them to believe in science instead of just praying for heaven's blessing.

At this moment, everyone was more and more excited as they listened, casting their burning gazes toward Su Liang one after another.

However, just as Su Liang was explaining how rain was formed, Li Er stared fixedly at Su Liang and opened his mouth: "According to what you said, wouldn't it be possible to change the conditions for rain under certain circumstances?"

Su Liang nodded slightly upon hearing this.

He then looked at everyone and continued: "That is indeed the case. Under certain conditions, artificial rain can be implemented."

Getting Su Liang's confirmation, Li Er was overjoyed.

These days, Li Er had also kept what Su Liang said in his heart. Hebei hadn't rained for more than three months; it seemed Su Liang was right. Li Er then fixed his gaze on Su Liang, looking at him with anticipation.

Su Liang also felt Li Er's gaze at this moment and said indifferently: "Hehe... I understand Your Majesty's thoughts, but it is impossible to do artificial rain now."

"Not to mention whether natural conditions allow it, currently, it is impossible to send artificial rain materials to an altitude of 16,000 li."

As Su Liang's words fell, Li Er's face clearly darkened. The greater the hope, the greater the disappointment.

"Then... then how long will it take for you to be able to do it?" Li Er asked unwillingly.

"This... this will probably take a month," Su Liang said indifferently.

Actually, Su Liang could do it himself after a few days of hard work, but Su Liang didn't want to be so tired.

Moreover, the matter in Hebei had already been arranged properly and wouldn't cause any major problems, just a little less grain harvest.

After Su Liang finished speaking, he couldn't help but think of one thing: it would be great if he could connect the Shandongbandao and the Liaodongbandao. In a few years, the Bohai Sea would definitely become the largest freshwater lake in China.

Although the South-to-North Water Diversion Project could alleviate the problem of water shortage in the north, it was far from enough.

The average depth of the Bohai Sea was only 18 meters, and the deepest place was no more than 85 meters. The distance between the Shandongbandao and the Liaodongbandao was only 110 kilometers, and there were some small islands in the middle. In this way, one only needed to build a dam of about 100 kilometers.

Su Liang couldn't help but have this idea in his heart. It seemed that after the road was built, he would have to go out for a walk.

The information transmitted by the Bu Liang Ren (Secret Police) in recent days didn't seem like much on the surface, but Su Liang saw it very clearly.

It was feared that it wouldn't be long before Goguryeo would unite with Baekje to launch a large-scale attack on Silla.

Although this matter was irrelevant to the Great Tang, if these two countries took Silla, the situation would be hard to say. ===== CHAPTER 42 =====