The rotation of the celestial sphere is a very complicated process.

Generally speaking, it spins around a certain "center" at a regular speed, but the position of the center is constantly changing. In addition, the speed of rotation is too fast, so it is difficult to calculate in advance to determine the direction, and you can only find it along the direction of rotation.

Immortal Chisong, Sect Leader Ziwei and Qiu Changtian flew up into the sky on their swords.

As the altitude gradually increased, the strong wind became more and more violent and difficult to control, and the demonic sound became gradually clearer.

The headmaster Ziwei and the immortal Chisong were both very powerful, so they were naturally not afraid. Qiu Changtian, on the other hand, had a clear mind and simply ignored the harassment of the demon's phantom sound, only thinking it was very noisy.

He had just arrived in the Ninth Heaven and did not have much experience, so the strong winds initially made his sword shake. However, he soon mastered the laws of the wind and the sword gradually stabilized.

Continuing to ascend in altitude, as the sea of ​​clouds moved farther and farther away beneath his feet, Qiu Changtian gradually saw that the sky above his head was changing from the azure blue of the ocean to a multi-colored hue like a glass cover.

This is the sky, a world barrier that protects the world of cultivation from the chaotic Milky Way, the many stars, and the demons from outer space.

After approaching the sky, Qiu Changtian discovered that the sky was not colorful, but colorless.

But there are countless densely packed tadpole characters on it, moving rapidly and uniformly in a certain direction - different angles bring about changes in the refraction of light, and the corresponding runes in different positions have different colors, emitting dazzling and brilliant light as the sky rotates at a high speed.

They moved so fast that it was impossible to make out the specific patterns of each tadpole pattern. All one could see were countless torrents of ever-changing colors, rushing straight and neatly in a certain direction.

"All immortal seals will rotate around the center of the vortex." The Red Pine Immortal stroked his beard and said, "Therefore, we only need to go perpendicular to the direction of the movement of the immortal seal and go south to find the center of the vortex."

The three continued to fly south, and finally arrived at the center of the vortex somewhere over the South China Sea.

The closer it got to the center of the vortex, the slower the tadpole runes moved, until it approached the three layers of runes surrounding the center of the vortex, and the speed was slow enough to be clearly discernible.

As for the center of the vortex...there was nothing strange about it. It was just surrounded by a circle of the slowest rotating tadpole patterns and moved rapidly to the west.

"In spring and summer, the center of the swirl moves from north to south; in autumn and winter, the center of the swirl moves from south to north." The Red Pine Immortal continued, "Around noon, the center of the swirl moves from east to west; around midnight, the center of the swirl moves from west to east."

"So the center of rotation performs simple harmonic motion with a long period in the north-south direction." Qiu Changtian thought to himself.

"Even the vortex of the sky itself moves as fast as lightning." Immortal Chisong concluded, "If the entrance to the secret realm of the Seven Treasures Mysterious Garden is really attached to a certain position on the celestial sphere, then its movement speed must be beyond imagination."

"There must be some other way to locate Qibao Xuanyuan." Master Ziwei tried to smooth things over, "Chang Geng, just think and guess. The immortal and I will help you verify it."

Let me just think and guess, so your brains have all degenerated?

Qiu Changtian complained for a moment and had to continue thinking.

In his opinion, the Seven Treasures Mysterious Garden should be in the sky. The reason is very simple: the Baiyujing Secret Realm is in the deep mountains, and the Huangjinque Secret Realm is in the sky. If the altitude is increased, the Seven Treasures Mysterious Garden will be at the barrier of the sky. From a regular point of view, there is a trace to follow.

Continuing the analysis from the entrance of the secret realm, the entrance to the Baiyujing secret realm is in Tianmu Mountain, and the entrance to the Huangjinque secret realm is in Xihua Mountain, so the entrance to the Qibao Xuanyuan should also be in a mountain.

However, this conclusion obviously conflicts with the previous one. Where are the mountains at the height of the Sky Barrier?

Hey, wait...

Qiu Changtian suddenly realized something and asked:

"I heard that there was a so-called pillar of heaven in ancient times. Is it true?"

The "pillar of heaven" here, of course, does not refer to the Kunlun Pillar of Heaven, but to the three large pillars that are said to connect China and the sky.

Since the sky is a big sphere and Shenzhou is a flat plate inside the sphere, it is entirely through the connection of these three pillars that the Shenzhou continent is completely fixed in the celestial sphere - or more accurately, it is suspended below the sky.

Later, a pillar in the east broke, causing Shenzhou to sink eastward as a whole. Therefore, all the rivers in Shenzhou flow roughly from west to east.

"Yes." The Red Pine Immortal replied, "There are two remaining pillars, one in the far west and one in the far north."

"Can you take me to see the Pillar of Heaven in the Far North?" Qiu Changtian asked.

Immortal Chisong had no objection, so the three of them quickly turned north.

Crossing layers of ice fields and across the vast North Sea, just when Qiu Changtian was complaining in his heart that no matter in the cultivation world or the Eastern Emperor Realm, the North Sea was too cold, he suddenly saw a huge outline vaguely emerging in the white ice fog in front of him.

That is the Heavenly Pillar located at the extreme north. Unlike the "exaggeratedly named mountain" such as Kunlun Heavenly Pillar, this Northern Heavenly Pillar is actually a large pillar - the diameter of the pillar is extremely exaggerated, and it is impossible to tell what material it is made of. The color is dark gray, and it stands upright between heaven and earth.

Qiu Changtian followed Master Ziwei and Immortal Chisong and arrived at the edge where the Sky Pillar and the sky dome were connected.

I saw the tadpole patterns flowing on the celestial sphere, which began to diverge from both sides at the junction of the celestial pillar and the dome, bypassing the celestial pillar itself.

Near the connection, there is another kind of strange text - they look like the same style as tadpole script, but they neither flow nor glow. They are engraved near the top of the pillar, and no one knows what they mean or what role they play in connecting the pillar to the sky.

"A Jing." Qiu Changtian asked in a low voice, "Can you understand the meaning of these tadpole characters?"

"I don't know." Kunlun Jing said bluntly, "I can't do anything about things like this that involve the origin of the world."

"This is the Far North Sky Pillar." Immortal Chisong said, "Chang Geng, do you have any ideas?"

Qiu Changtian stared at the Tianzhu and suddenly said:

"There are three pillars in the sky: one in the north, one in the southwest, and one in the southeast... The southeast pillar has collapsed, so only the north and southwest pillars remain."

"And the center of the celestial vault roughly moves back and forth from north to south. In other words, the center of the celestial vault may coincide with the northern celestial pillar, but not with the southwestern celestial pillar. Is that right?"

"It's roughly the same," said the Immortal Chisong. "Although the center of the vortex will move back and forth every day, the distance it moves is not that great. It will not reach as far as the southwest pillar of heaven."

"If the Seven Treasures Mysterious Garden Secret Realm is really attached somewhere on the sky barrier and moves rapidly with the rotation of the celestial sphere." Qiu Changtian said slowly, "and the secret realm itself has to design a method for cultivators to enter, then it must be when the secret realm is closest to the center of the rotation."

"Looking at other secret realms in the past, the Baiyujing secret realm was opened in Tianmu Mountain, and the Huangjinque secret realm was opened in Xihua Mountain. Then, will the Qibao Xuanyuan secret realm be opened on this Extreme North Sky Pillar? If the Extreme North Sky Pillar is regarded as a kind of 'mountain', it is reasonable."

"When the center of the sky reaches the location of the northernmost pillar, perhaps we can find some clues from it... There is too little evidence to infer now, and I can only make random guesses. Master and the immortal will laugh at me."

"That's fine." Immortal Chisong waved his hand and said, "When the Sky's Rotating Heart reaches the extreme north, we have to wait until the winter solstice."

"There are no other clues, so I'll wait until the winter solstice to come here and do some investigation."