"Black holes are formed due to the collapse of the gravity of rotating celestial bodies, and we assume that in the vicinity of a rotating black hole, light is emitted in all directions, so that when the light is pulled inward due to gravity, it will also be pulled in the direction of the black hole's rotation because the black hole pulls the surrounding space-time, so even if the light itself intends to fly straight into the center of the black hole, it will still move away from the center at some point......"

In a lecture hall of the School of Physical Sciences of the Graduate School of the Chinese Academy of Sciences, at this time, Zhou Chen was defending his master's thesis, and sitting below him were the judges of the defense committee and some graduate students who participated in the defense like him. Pen @ fun @ pavilion wWw. ｂｉｑUｇE。 ｉｎｆｏ

As a graduate student in the direction of astrophysics, Zhou Chen has loved astronomy since he was a child, and chose to major in physics in college, and when he was about to graduate, he worked hard to study the radiation mechanism and measured astrophysics related knowledge in "Classical Electrodynamics" and "Astrophysics", and resolutely applied for the academic master's degree under the Graduate School of the Chinese Academy of Sciences and was successfully shortlisted.

Astrophysics is an obscure discipline in China, although there is no shortage of experts and scholars in China who have made achievements in this field, but due to the narrow work area after graduation and the strong requirements for professional knowledge of the discipline itself, even in the Graduate School of the Chinese Academy of Sciences, the number of students recruited each year can be counted with a slap.

On the podium, Zhou Chen showed PPT while skillfully introducing his graduation research according to the prepared draft, and the whole process was neither humble nor arrogant, reasonable, and extremely confident.

Many of the teachers and students below seemed to be moved by the young man on the stage, and they all listened attentively, taking notes on the key parts from time to time.

In the blink of an eye, the PPT display of more than 20 minutes was over, and Zhou Chen began to make a closing speech and thanks step by step, and when he finished his statement, the whole lecture hall sounded a whispered discussion, and the judges of the defense committee were communicating with him about his defense.

According to the fixed process, the next step was the question session, but it was clear that the exchange between the judges was not over yet.

At this moment, an old man with gray hair looked up and smiled at him, indicating that he had a question to ask.

This is a veteran professor in the Graduate School of the Chinese Academy of Sciences, as well as the vice dean of the School of Physical Sciences and an authority on astrophysics.

Don't look at Professor Liang Zhiyuan's smiling appearance, everyone present knows that Professor Liang Zhiyuan will not ask questions in the course of the graduates' defense, and once interested, the questions asked are definitely a disaster for the respondents.

Therefore, when they saw Professor Liang's smiling appearance at this time, everyone stopped communicating and turned their eyes to Zhou Chen on the stage, looking forward to what kind of questions Professor Liang would ask, and at the same time, they couldn't help but sweat for Zhou Chen.

Professor Liang said: "After listening to your report on black holes, I have a feeling in my heart that a new generation of people will replace the old, and in general, your report is of great quality, but I have a doubt now, I hope you can answer it for me." ”

Here it comes!

Everyone was focused.

According to Penrose's inference, particles with lower energy will gain energy from the energy layer after passing through the energy layer, so that they have high energy when they pass through the energy layer, so that the energy layer will be thinner, and so that the energy layer will be thinner, because these energies are the kinetic energy of the black hole, so the kinetic energy of the black hole will also decrease after the energy layer is thinned. When the energy layer disappears, the Kerr black hole degenerates into a non-rotating Schwarzschild black hole, at which point the particles can no longer extract energy from the black hole. ”

"So let's think the other way around, if the black hole is spinning faster and faster, then its inner and outer horizons may merge into one, and then the black hole becomes an extreme Kerr black hole, and if the speed is a little faster, the event horizon will disappear, and the odd rings of the Kerr black hole will be exposed, which is contradictory to Penrose's cosmic oversight hypothesis. So how do you explain the problem, is the assumption of extreme Kerr black holes wrong, or is Penrose's assumption of cosmic supervision wrong? ”

After listening to Professor Liang's question, everyone present fell into deep thought, this question can already be called tricky, is the extreme Kerr black hole assumption wrong? Or is Penrose's cosmic oversight assumption wrong? No matter which one it is, it is not something that Zhou Chen, who is now just a "master's student to graduate", can put a beak.

Astrophysics, especially in areas that provoke thought, such as black holes and the origin of the universe, is not only covered by the word "science", it belongs to the category of philosophy, and since it is philosophy, no one can prove the other wrong, because there is no means of proof.

Professor Liang's questions are a bit big and deliberately embarrassing, but at the same time, everyone knows that no matter what the answer Zhou Chen gave, he can successfully pass this graduation defense, just because the quality of Zhou Chen's thesis has reached the level of asking questions from Professor Liang.

Moreover, Professor Liang's question itself did not have the right answer, he only examined Zhou Chen's reaction.

I saw Zhou Chen think carefully for a while, and soon his slightly frowning brows relaxed, as if he had found the answer.

"Just now Professor Liang asked me whether the extreme Kerr black hole assumption is wrong, or Penrose's cosmic supervision hypothesis is wrong, and my answer is - in fact, the extreme Kerr black hole hypothesis and the cosmological supervision hypothesis are correct, because I think that the rotation speed of the extreme Kerr black hole cannot be increased endlessly, it has a premise, when the rotation speed increases to a certain extent, it will not increase again, so the event horizon will not disappear, and the odd ring will not be exposed to the outside......"

He took a deep breath and replied with the same smile.

After speaking, he glanced down and found that many of the people below showed a contemplative expression.

Such an answer may seem like sophistry, but when you study the unknown, it is not whether your answer is correct or not, but whether you can come up with a hypothesis and then test it bit by bit.

Zhou Chen threw out his opinion very bluntly, such an answer had met Professor Liang's requirements, so he nodded.

Next, the other expert tutors of the defense committee also asked their own questions, and their questions were much simpler than those of Professor Liang, and the podium seemed more comfortable last morning, and answered them one by one.

Finally, in the applause, Zhou Chen ended his master's degree graduation defense and successfully obtained the graduation qualification.

――――――――――――

"Zhou Chen, you kid can do it, you can still face Professor Liang's questions without changing your face, brother respects you as a man!"

Out of the lecture hall, Li Kaiyan, who was defending with Zhou Chen, couldn't wait to speak.

Zhou Chen smiled, this Li Kaiyan is mostly admiring his ability to "open his mouth", an extreme Kerr black hole hypothesis, a cosmic supervision hypothesis, he put an iron hoop on the extreme Kerr black hole in one sentence, or made this feat in front of a bunch of experts, he really has a bit of the courage of Mount Tai to collapse in front of him without changing his face.

Li Kaiyan is also a graduate student in astrophysics, majoring in radio astronomy, so he is naturally afraid of questions from industry bigwigs such as Professor Liang, at this time he does not think that what Zhou Chen said on the stage just now is the truth, and in his heart he only thinks that it is Zhou Chen's wording to deal with the judges.

"But how does he know that what I'm talking about isn't true!"

Zhou Chen sighed in his heart, and walked towards the dormitory under the increasingly hot sun in early summer.

"By the way, now that you've graduated, do you have any plans? Do you want to work directly, or do you want to continue to take the exam? ”

Li Kaiyan is also lucky, his job has been settled before graduation, after the recommendation of his mentor, Li Kaiyan will work in the radio telescope monitoring department of the Shanghai Astronomical Observatory, and will report in a few days. Therefore, when speaking, there is no confusion and pressure to enter the society.

"It's not clear." Zhou Chen shook his head and replied.

"How can I not know, this is a major event related to the trajectory of my future life!"

When Li Kaiyan heard that Zhou Chen had not made a plan for his future, he was more surprised than even more puzzled.

It is said that with Zhou Chen's ability, whether he works directly or continues to take the doctoral exam, he has good conditions, and he himself is not an indecisive character, how can he not make a decision when he is about to leave school?

"Xiao Kai, you said that if there are aliens attacking the earth in 45 years, do you think we humans have any hope of winning?"

Just when Li Kaiyan was confused, Zhou Chen suddenly asked without a head.

"What? Aliens attack Earth? You're not kidding. Li Kaiyan glanced at Zhou Chen in amazement, laughed and said: "Let's not talk about whether there are aliens in the universe, even if there are, how do you know that aliens are here to invade us, not to be good neighbors and friendly with us?" ”

"Aliens come all the way to be good neighbors with us? I think you're the one making the joke. ”

Zhou Chen felt a little amused at Li Kaiyan's innocence, as if he was mocking Li Kaiyan for not having a sense of distress.

Li Kaiyan couldn't hold back his face, and said with a smile: "Okay, even if aliens are not good neighbors and friendly to us, but then again, it is not certain whether there are alien civilizations in the universe!" ”

"Do you really think so?" Zhou Chen asked rhetorically.

The origin of life requires countless accidents and harsh conditions, but the universe is so vast that there are more than 200 billion stars in the Milky Way galaxy in which we live alone, and about 100 billion galaxies have been observed by humans so far. How many accidents can be bred by such a huge number? If it is said that there are no aliens, Li Kaiyan himself does not believe it.

The closest star to the solar system is Proxima Centauri, which is 4.22 light-years away, but life may not be born there, and the search for a planet suitable for life is at least a dozen light-years away.

In other words, if an alien civilization does come to Earth, then the level of technology must be far higher than that of Earth.

"Again, what would you do if there were extraterrestrial civilizations and those aliens would arrive on Earth in 45 years?"

Zhou Chen looked at Li Kaiyan with a rare seriousness on his face.

"I think you're on the same page with that."

Li Kaiyan saw Zhou Chen's serious face, so he put away the cynical smile on his face, "If there is really an alien civilization coming to Earth and planning to invade us, then we will definitely not be able to fight, but if we can't fight us, can't we hide?" ”

Li Kaiyan suddenly said in high spirits: "Isn't there still 45 years left?" If I am given the opportunity, I will definitely lead all human beings on the earth to do their best to develop science and technology in the short time left, and then rush out of the earth and flee to the depths of the vast universe! ”

At this moment, Zhou Chen was finally amused, Li Kaiyan, this kid said domineeringly, but in the end, it was just such a way to escape in embarrassment.

But when that time comes, escaping the earth is probably the last chance.

"Maybe the planet fleeing is a way out."

Zhou Chen muttered in a low voice.