The black Audi drove into the gate of Peking University and slowly stopped in the open space in front of the office building.

The rear door opened, and two wooden-faced 'security' personnel took the lead in coming out, and after quickly inspecting the surrounding situation, they gave way and let Zhou Xing get out of the car.

Zhou Xing walked out of the car door, and immediately saw three or four people surrounding Director Zheng, smiling towards him.

"Haha, long time no see, Zhou Xing!" Director Zheng excitedly reached out to shake Zhou Xing's hand.

"Don't come closer!" a nearby security guard stepped forward, stopped him, and shouted a warning.

Hearing this, Director Zheng's face froze,

"It's okay, it's safe, you get out of the way. Zhou Xing commanded with a smile.

Hearing the order, the security personnel turned sideways and moved out of the way, but his emotionless eyes were still on Director Zheng's body, and as long as there was something wrong with him, he would stop it.

"I'm going to bother you again, Director Zheng!" Zhou Xing smiled embarrassedly and held Director Zheng's hand.

"Haha, you're polite, you're so polite! Aren't you still a student of Peking University, although the situation is a little special, but Professor Li is still quite happy to teach and solve doubts, especially after hearing that it is you, they are very happy. Director Zheng smiled and waved his hand.

"Yes, it's trouble!" Zhou Xing smiled and nodded.

"Well, I've got a classroom for you. Director Zheng made an inviting gesture and led the way for Zhou Xing.

Zhou Xing nodded and followed Director Zheng's footsteps to the classroom that Director Zheng said.

"Xiaoxing! This time you are going to develop that direction, is it a physics problem this time?" Director Zheng led Zhou Xing to the classroom and curiously explored.

"Hehe, I'm not going to develop anything, so I'll ask a few professors about my learning problems. Zhou Xing explained with a smile.

"Xiaoxing, I know you may be mindful of the matter of the nano medical cabin, I never thought that things would turn out like that, the school only needs a little reputation, and I never thought of monopolizing the entire project. Director Zheng explained to Zhou Xing anxiously.

"I know, it's all in the past, if I still mind, I won't go back to school!" Zhou Xing shook his head with a smile.

Hearing this, Director Zheng immediately breathed a sigh of relief.

Director Zheng's eyes showed a determined gaze, and he looked at Zhou Xing and swore and promised: "En'en, then I won't get to the bottom of it! Xiaoxing! The door of the school will always be open for you, and you can come over if you encounter any problems." ”

Zhou Xing nodded, showed a happy smile, and said with a smile: "Thank you, director, just like you just said, I am still a member of the school, and I will definitely continue to win glory for the school if I have the opportunity." ”

Director Zheng's eyes lit up and he was very happy, Zhou Xing's sentence was equivalent to admitting the 'deal' between them, no matter what Zhou Xing wanted to do, Peking University would be able to get a little light.

Soon, Director Zheng took Zhou Xing to a lecture hall.

The door of the classroom was open, and when footsteps were heard, the four old professors of different heights and temperaments stopped their discussion and turned their heads one after another.

This is Professor Li Jing, graduated from Columbia University: first-level discipline teaching: physics, second-level discipline teaching: agglutination state physics, main research directions and characteristics: magnetic nanostructures and low-dimensional physics, magnetoelectronics, magnetoelectronics and magnetic materials. Director Zheng pointed to a middle-aged man in his fifties, with a bun-shaped face and a tall figure.

"This is Professor Xu Wen, graduated from the University of Bielefeld, and teaches first-level teaching: computational physics, and second-level teaching subject: grid QCD,...... , the main research direction: lattice quantum field theory. ”

"This is Professor Zhang Hua,......。 ”

"This is Professor Chen Yuxin,......。 ”

Director Zheng introduced the four professors to Zhou Xing one after another, then looked at the four professors, and introduced Zhou Xing beside him with a smile and said, "Professors, you must all know this one around me!"

"I know, of course I know! I've only heard his name, but I haven't seen anyone, but now I finally see me!"

"I didn't expect the super genius to step into the field of physics! ”

"Haha, I've been looking forward to it day and night, and I'm finally looking forward to you!"

"Yes, yes! Classmate Zhou, there is a way in heaven that you don't take, but you have to break through the physics door, this level is not easy!"

Hearing this, the four professors looked at Zhou Xing with bright eyes, and nodded their heads one after another.

"Professors, student Zhou Xing greets you and asks for a lot of advice. Zhou Xing greeted the four professors with a smile.

"Don't be polite about what to teach! If there are any problems, we will discuss them. Professor Xu Wen said with a smile.

"Yes, yes, Lao Yan, they have not publicized your deeds, don't pretend to be a big-tailed wolf!" Professor Li Jing said with a smile.

"Haha! That's right, that's right! Don't mention what to teach, otherwise you won't be able to get off the stage if you ask, it will be too embarrassing!" Professor Chen Yuxin nodded again and again with laughter.

There is no vanity under the fame, Zhou Xing's name is famous all over the world, his intelligence, knowledge, and research ability must be extraordinary, and the professors looked at Zhou Xing with a smile on their faces, and they all did not dare to accept his greetings.

"Professor, you're overrated. Zhou Xing smiled, unwilling to be polite, and changed the topic: "Professor, I encountered a special problem when I was studying physics, and I want to ask you for advice. ”

"Huh?"

"Just ask!"

"What's the problem?"

"What's the problem?

The four professors looked at Zhou Xing with solemn expressions, and responded in unison:

"Evolutionary mechanics: Velocity in physics is relative, and each velocity value must be relative to a particular reference. For example, if the speed of a ship going down the river is 3 m/s, and the speed of the ship is 4 m/s, then the speed of the ship relative to the bank is 7 m/s. Zhou Xing said lightly.

"Yes, that's the basic idea of physics. Professor Li Jing nodded.

"The speed of light is about 300,000 km/s, why does physics consider this velocity value to be relative to "any inertial frame"?" Zhou Xing asked, puzzled.

This is a basic assumption of special relativity. Professor Xu Wen said with a frown.

"This basic assumption contradicts the concept of velocity in physics, why do you accept such an assumption?" Zhou Xing asked even more puzzled as he looked at the four professors.

"There's no way, if you don't accept such a point of view, there will be serious contradictions in physics?" Li Jing sighed and said helplessly.

"What serious contradictions will there be?" Zhou Xing asked.

"In physics before the special theory of relativity, it was necessary to require the existence of an absolutely stationary frame of reference (abbreviated as an absolutely stationary frame, absolute space, or absolutely stationary aether), but a large number of experiments could not prove the existence of this absolutely stationary frame, which is a serious contradiction. Professor Xu Wen introduced.

"The velocities of physics are relative, and the velocities of the same object will have different velocity values relative to different frames of reference. Speed in physics doesn't have to depend on an absolutely stationary system. ”

"Yes. However, "acceleration" in Newtonian mechanics is absolute, as are "certain velocities" in electromagnetism and electrodynamics, which must rely on an "absolute stationary system".

"Let's not discuss electromagnetism and electrodynamics for the time being, let's talk about "acceleration" in Newtonian mechanics, why is "acceleration" in Newtonian mechanics absolute?

“……。 ”

After a while, Zhou Xing and the four professors entered the state of learning to discuss the field of physics, and Director Zheng and the others who followed him were stunned.