Alke was slightly puzzled: "Hmm, didn't Enrica tell you, the Holy Tower is a place to seek truth, the most sacred place of my Yago tribe, and it is also a place for Taoism. ”

He raised his hand and pointed upward, then continued: "The sixth floor of the Tower of Truth contains countless books, only the Great Wise or the Great Sages of our clan can step into it, and from the first to the fifth floor, you will meet five Gatekeepers in turn, as long as your answers can satisfy the Gatekeepers, you are eligible to enter the next level. ”

"Wait, we are Wenbi?" Nian Yubai still couldn't react.

Alker smiled and said directly: "My question is, why can't everything in the world be free from the shackles of the earth?

Nian Yubai and Late Winter stared wide-eyed, completely confused.

He coughed twice, barely squeezed out a smile and said, "Can we discuss, can we change the problem?"

Alker still maintained an impeccable smile: "If you choose to give up, please bring it with you when you leave, thank you." ”

Nian Yubai smiled bitterly: "Isn't this a normal thing, what's there to ask? Can't you ask something meaningful?"

Alker smiled, "This is the truth we seek, and it has no meaning. Or, what is the meaningful thing you are doing for it?"

Nian Yubai has a head and three big, and he only feels completely unable to communicate.

Yuling breathed a sigh of relief, fortunately, the other party's question is quite routine, at least any junior high school student from the earth can talk about it with confidence, even if he doesn't study well, he can easily say the answer.

Thanks to Newton.

"Because the world has a gravitational pull, nothing can stay in the air for a long time, and even if it is forcibly thrown up, it will fall on its own. ”

"Gravity? Interesting, can you explain it to me?" Alker nodded.

Yu Ling searched his stomach and recalled some distant knowledge, and continued: "There is an interaction between any object, they attract each other by the force in the direction of the concentric line, the greater the mass of these two objects, the greater this mutual attraction, and the farther away they are, the smaller the attraction will become. And we live on this land, and the mass is negligible compared to the mass of the planet under our feet, so most of the objects on the planet cannot be separated from the attraction of the planet. ”

Nian Yubai and the others had no idea what he was talking about.

Only the opposite Alke showed an excited expression, patted his head and said: "Ah, your statement is very similar to the Great Sage of Mo Ling, at that time, several Great Sages were arguing over this issue, although I always felt that the Sage of Mo Ling was right, but I couldn't find evidence to prove it, hmm...... Your idea is clear, and even if there is no evidence, it is very convincing. ”

"However, I have a few more questions I would like to discuss with you. If everything has a tendency to attract each other, why don't we affect each other?" Alker continued.

"Of course, there is a gravitational force between any of us, but until the mass reaches a certain level, this gravitational force is very small and the effect is negligible. The mass is as large as the planet, and the gravitational attraction between them is subject to distance, if they are close to each other, they will form orbits around the stars, and the satellites will rotate around the planets, one step at a time, but if the distance is far, the two sides still do not interfere with each other, which is the rule of the universe. Of course, I may be simplifying this, and there are factors such as centrifugal force and centripetal force, and gravity is only one of the countless basic rules. ”

Alker said embarrassedly: "I was so excited just now that I forgot that you said a long time ago that gravity is proportional to mass." ”

"To be precise, it is proportional to the product of the masses of the two objects. ”

"Hmm, then why do you Terran cultivators be able to break free from gravity when they reach a certain level of cultivation?"

"I haven't looked into this issue in depth...... But gravitational attraction is also a force that always points to the center of the sphere, so if we give objects an opposite force, they can briefly leave the earth and fly into the air. What the cultivators do is to prolong this process as much as possible, during the marrow washing period, the martial artists cut the scriptures and wash the marrow, so that the body is transparent inside and outside, and the impurities are exhausted, so as to achieve the state of unity between heaven and man, they change their physique, and resist the shroud of gravity with the mysterious power of the body. But if they don't cultivate at this level, their strength will not be enough to free them from the shackles of gravity, which is a problem of quantitative change causing qualitative change. ”

Alker nodded thoughtfully, "Last question, what is it that produces what you call gravity? What is its nature?"

Yu Ling couldn't help but be slightly stunned, although he was able to pick up a bargain with the crystallization of the wisdom of the earth scientists, but it turned out that the Yago people were not so stupid and easy to fool, and they were just a young man in front of them, and they would draw inferences from each other and go deeper into the problem of the essence of power step by step.

Forgive him for only having a pitiful amount of knowledge, this problem is obviously beyond his ability, and it may be similar if he were replaced by a science tyrant.

"I don't know about this, the cause of gravity should be related to the magnetic field force and the spin motion of charged particles, its essence may be a depression in space, I haven't understood what is going on. Yuling said honestly.

Alke's eyes lit up when he heard two new terms, but he opened his mouth, and finally said with some regret: "I've asked too many questions, I can't delay your time any longer, you can often come to me to discuss when you have time in the future, and now I'll send you to the second layer." ”

The light in front of them shone like an ocean, and when the three of them subconsciously closed their eyes and opened them again, they had already arrived in another silent space. There are also a lot of scattered points of light here, but compared to the infinite expanse of the first layer, it seems much sparse in front of you.

A blue point of light fell from the sky and turned into a middle-aged man, who was sitting at the table with a smile on his face: "Hello, I'm Kurlan Weide, and it's a pleasure to meet the distinguished guests of the Terrans. ”

"Hello, Mr. Weed. Yuling also returned the salute.

Nian Yubai came to his senses and whispered, "Ah Ling, what were you talking about just now, why do I know the meaning of every word of yours, but I don't understand it when it comes together?"

At the end of the winter, he also raised his head and said with a look of adoration: "Brother Yu is so powerful, although I don't understand what you're talking about, I just feel that you are very powerful." ”

...... Is it really necessary to be proud of the kind of common sense that middle school students know?

Yuling could only be speechless.

Courland smiled and groaned, "My question is, do you think the future can be predicted?"

"There's no set answer to this, is there?" Yu Ling looked at him.

"That's right, it's not so much a question as a discussion, six of the nine great sages of our Yago clan are trying to predict the future, and the last one is a sixteen-character proverb: Absolute Yin and Spirit, Ice and Snow Melt, Dark Yuan Reappear, Snow Realm Unified, until now we don't know if it will come true. Sometimes I can't help but wonder if we should predict the future, and if we know a predetermined outcome and can't change it, then maybe it's better not to know it from the beginning. Courland said with some sadness.