When the rope ladder is set up, climbing is a great problem. Naturally, Hao Zhisong Xiaojia is nothing to say, and the two geologists are OK.

The rest of the group are scientists sitting in the laboratory. They usually don't work hard and lack exercise. He Gang, the only soldier, hasn't recovered from the injury on his left shoulder. It's really a big challenge to climb over a distance of 50 meters with only two ropes in such a deep underground.

Fortunately, there was a pulley in the climbing equipment carried by the team. Hao Zhi hung the pulley safety lock on the rope above, made a sitting pocket with the rest of the rope and let people sit on it. Song Xiaojia, who passed first, dragged them over, half climbing and half dragging, and sent them to the other bank one by one.

All the people stepped on the solid ground with fear, and a hanging heart fell to the ground.

"Comrade Hao!" Professor Lynch finally asked, "how did you bolt these two safety rope ladders?"

"Ah... This... This is a trade secret!" Hao Zhi laughed and laughed, but buried eternal curiosity in the hearts of everyone.

The team continued to move forward and fumbled towards the depths of the cave. The previously mottled and abrupt reefs have been gradually replaced by smooth rocks. After crossing the canyon, the landforms on both sides are obviously different.

Geological experts explained to everyone as they walked that the early cave was caused by the impact of sea tide. The sandstone and limestone under the cliff were light and soluble, so they were gradually washed out of the cave under the impact of tens of thousands of years, and the trench obviously prevented the sea water from eroding the cave wall when the sea tide rose, so the landform has changed greatly.

Most of the rocks that make up the cave here are shale, which is like the section of a book. They are pressed together very carefully, with edges and corners. The edges are as neat as knives and axes. With rich and colorful colors and strange shapes, a group of people have opened their eyes and enjoyed it while walking.

The whole route is high and low, but the overall terrain is more and more inclined downward, as if to explore into the boundless underground. Behind us, the cave exit has long been thrown out of the sky, and there is no time to return.

Hao Zhishun slowly slid down a huge slope to the bottom of the cave. He walked forward with the people. He suddenly looked up and saw a thick triangular rock protruding from the top of the cave. In front of the top of the triangle, a naturally formed waterfall was flying down, with a drop of more than ten meters and a width of two or three meters.

"Oh, my God! How could this be possible?" Lynch, who was walking in front, exclaimed.

"It's just an underground waterfall. I haven't seen the world!" Hao Zhi muttered. He followed the team to climb up to the triangle rock. When he looked back, he found that all the people stayed in place and couldn't close their mouths.

Hao Zhi realized that the key to the problem was that in such a closed underground cave, a drop of water falling on the ground would have a huge echo, not to mention the waterfall with a drop of more than ten meters high?

Just climbed up all the way, the cave was always very quiet. The waterfall didn't seem to fall from the sky. Where was the impact?

Until we came up around the rocks below, a magical scene appeared in front of everyone. It was half a waterfall!

Yes, half! Hao Zhi watched the waterfall fall from the sky like a magic show. Thousands of tons of water suddenly disappeared on a cross-section hanging in the air!

It's like there's a huge bowl mouth followed by the water, and the bowl is invisible!

The waterfall is less than two meters away from the ground, and then magically disappeared!

Like a silk that hangs down but is cut off with scissors, it flutters with water flowers and disappears in front of everyone playfully.

Everyone gathered around in disbelief, but no one dared to rush forward. Only by observing from a distance, many professors trembled with excitement. He tried his best to wipe the mirror, and then awkwardly climbed onto a half man high stone and looked down.

"A natural four-dimensional entrance!" exclaimed professor nado.

"What?" Professor Lynch, who was also a physicist, quickly stood up and looked at it for a long time. He looked at the professor. They both saw the excitement in each other's eyes.

Hao Zhi and Jia Jia also hurriedly found a high place. Looking down from above, they saw a strange scene in front of them. Under the impact of the water, there was a translucent ball floating!

The ball doesn't seem to be an entity and has no texture. It's just the shape surrounded by water. It's four or five meters in diameter. You can't see the inside. Every drop of water hits it. It doesn't splash like it's generally understood. Instead, it seems to be firmly absorbed and directly enters the inside of the ball!

"This, this is incredible! A four-dimensional hole that casts a shadow in the three-dimensional world! Naturally formed!" Professor nado said excitedly.

"Where did the water go?" Hao Zhi asked, "there must be a place to go?"

"They still exist, but they are not perceived by the three-dimensional world!" Professor Naduo stretched out his palm and gestured with a finger, "It's like when three-dimensional passes through two-dimensional, suppose you pierce a piece of paper with a pencil, which is a model of three-dimensional passing through two-dimensional. For the little people who live on paper and draw lines, what they see in their world is a small black spot, which is the tip of the pen. Then, with the progress of the crossing process, the black spot they see will gradually become larger, That is the section of the pencil tip. Finally, there is a wooden section, even a circle of paint, but they can never see a whole pencil, nor can they understand the part of the pencil that has not entered the two-dimensional and pierced through the past. "

"But what we see is a ball. How can you say it's a hole?" Hao zhinao scratched his head and asked.

"Do you think the projection of three-dimensional on two-dimensional can only be a hole without thickness? The visible part of high-dimensional on low-dimensional can only abide by the physical rules of this dimension, so what four-dimensional presents in the three-dimensional world can only be a three-dimensional, three-dimensional ball, but in fact, it is a hole."

"Does this thing have any practical significance?" Hao Zhi said and looked at the four-dimensional hole again.

"For the same example, when a pencil pierces a piece of paper, there are actually two holes in the upper and lower directions of the paper. One is the entrance and the other is the exit. Right? In our opinion, the two holes can actually be understood as the same. The four-dimensional dimension is not the same. It has an entrance and there must be an exit. Theoretically, if we go in from the hole, we will go out from the hole in an instant The exit appears... It can not abide by the space distance law of the three-dimensional world. "

"I said..." Jia Jia whispered in Hao Zhi's ear, "it's not very similar to your ability. You are also an ant crawling in and out of such a hole every day!"

"Well, I'll try it in?" Hao Zhi stroked his sleeve and said.