Chapter 300: Unable to escape autism (one/three)

Accompanied by this classmate, Xu Mang came to a classroom in the Physics Department building, and he found a problem. This guy didn't bring books. There were more than 60 people in the classroom, and a dozen of them had no books.
What's the situation?
Does this major accept students?
"brothers?"
"Why didn't these people bring books?" Xu Mang asked curiously.
"Audit." The little brother said calmly: "Similar to you."
"..."
"What about you?" Xu Mang asked with a black line on his face.
"I?"
"Of course I'm also in attendance." The little brother smiled: "But I am better than those of them, including you, in astrophysics."
Damn it!
Encountered a pretender!
Good guy... dare to act in front of me Xu Mang?
Xu Mang’s anger has always been his own routines, but today he was given routines by others. The problem is being routinely given by a graduate student. This is the biggest stain in the history of his routines.
"Ugh!"
"Does your family know that you are so awesome?" Xu Mang asked helplessly: "Good fellow...you are obviously an observer like me, how do you pretend that you are a major in astrophysics?"
"..."
"You can't say that." The brother smiled bitterly: "I may be a little better than you, of course... I mean it's possible."
"Dare to ask my brother what is sacred?" Xu Mang asked.
"Du Yuan."
"Oh..." Xu Mang nodded and said silently: "Do you know who I am?"
Du Yuan froze for a moment, and said calmly, "Who are you? It has nothing to do with me. You are just meeting together. Maybe tomorrow, we won’t have any intersection, so if you don’t know the name, it’s better to be less concerned and more persistent. Read."
Xu Mang: (°ー°〃)
Damn it!
Encountered a well-matched opponent.
It feels like he is crazy.
soon,
A very dignified professor walked in and started the class directly without any name.
"Today we mainly explain the physical properties of neutron stars." Although this professor is impatient, he has a wealth of knowledge and can be inferred from his hairstyle and hair volume. After all, he is extremely smart.
"When a massive star evolves to an advanced stage, it will accumulate a huge iron nucleus through nuclear combustion. When this iron nucleus reaches a certain mass, it collapses due to excessive pressure, resulting in violent gamma-ray bursts and supernova explosions. A neutron star was born."
"In fact, a neutron star is a super-density star composed of neutron matter. How high is the density of a neutron star? Give you five minutes to estimate the density of a neutron star. First of all, the mass of the neutron star is about the same as the sun, and the radius is ten kilometers."
"The radius of the sun is 700,000 kilometers, and the density is (1.4g/cm^3)."
Words fall,
The professor said solemnly: "Let's start the calculation, the time is five minutes."
Soon everyone began to calculate. Of course, there were a dozen or so students who were in vain, sitting in their seats silently, waiting for the announcement of the answer.
Xu Mang watched the students who were present were making tense calculations, and couldn't help but feel a little confused, and asked curiously, "Hey...Is this a freshman?"
"How do you know?" Du Yuan said in surprise: "It is indeed a freshman."
"..."
"I don't even know the fast conversion of two stars of the same mass. What do you say is a new birth?" Xu Mang said helplessly: "When two stars of the same mass, their density is inversely proportional to the cube of the radius. ."
Du Yuan was taken aback for a moment, and said with a skeptical look: "Are you sure?"
"..."
"Are you doing research in the astrophysics group?" Xu Mang asked, "Don't tell me, you are solely responsible for calculations?"
Du Yuan nodded awkwardly: "Then do you know this density?"
"Any pen and paper?"
"Have!"
I don't know where Du Yuan took out the pen and paper and handed it to Xu Mang.
Less than ten seconds,
Xu Mang has completed the calculation of the neutron star density, Pns=(R/Rns)^3xP≈(700000/10)^3x1.4≈10^14(gcm^-3)
"give!"
After Du Yuan got the answer, he looked at Xu Mang with horror and asked cautiously: "Brother... right?"
"Try it." Xu Mang shrugged and said calmly.
The reason why Xu Mang gave in to the answer was that he didn't want to bear the title of autistic maker anymore. He wanted to give this title to Du Yuan.
Du Yuan thought about it, raised his hand hurriedly, and shouted to the professor: "Professor, I'm done!"
As soon as the voice fell,
Caused an uproar.
"you are..."
"Auditor?" The professor saw Du Yuan and saw that there were no textbooks on his desk, and he understood that this person was here to listen.
"Yeah!" Du Yuan nodded.
immediately,
The professor came to Du Yuan's side, glanced at his answer, couldn't help but praised: "Which department are you from?"
"Department of Mathematics..."
"I am in graduate school, and I happen to be in the astrophysics research group, responsible for calculation procedures." Du Yuan said seriously: "In order to strengthen business ability, so come to listen to the class, I have been listening to your class, some of your knowledge points, I Remember it all in my heart."
Xu Mang: (￣△￣;)
Talent!
Do not,
This is a wolf extinction.
"Not bad!"
"It's good to be self-motivated, keep working hard." The professor of astrophysics nodded repeatedly.
Immediately after,
The professor returned to the podium and continued to lecture.
"..."
"..."
Xu Mang looked at Du Yuan, Du Yuan looked at Xu Mang, neither of them spoke.
"brothers!"
"You are so awesome!" Du Yuan said at Xu Mang with a look of admiration: "Don't say anything, I will treat you at noon."
Xu Mang smiled bitterly: "You...how did you get admitted to Nanda?"
"I'm pretty good at math, but I don't understand astronomy at all." Du Yuan sighed: "If it weren't for mixing up a paper, ghosts would learn astrophysics."
"..."
"Thank you."
at this time,
The professor threw another problem.
"Pulsars are high-speed rotating neutron stars. Pulsars rotate very fast, and some can even reach more than a thousand revolutions per second. Such fast rotation, coupled with magnetic fields and extreme conditions, will cause the pulsar's poles to collimate. Electromagnetic radiation."
"Here is a question for you. Who can use numerical calculations to prove that pulsars are neutron stars?" the professor asked: "Think about it."
Xu Mang sat in the last row, witnessing everyone's dumbfounded look, like when he was in the past.
in fact,
Astrophysics is a brand-new major, which can only be accessed at university, and it is only available at top universities. These students are also unlucky... High schools have not taught these things at all.
It means that everyone starts from scratch. In addition to the professor's teaching, another channel is needed to acquire knowledge, otherwise they will definitely be eliminated.
"Paper and pen!" Xu Mang said.
"Oh..."
Du Yuan hurriedly handed it to Xu Mang.
quickly,
Xu Mang used the simple Newtonian law of universal gravitation and centrifugal force formula to prove that a pulsar is a neutron star. In fact, only one concept needs to be grasped. The centrifugal force of the pulsar is less than gravity, otherwise the pulsar will collapse.
According to this concept, very detailed calculations can be made through the law of universal gravitation and the formula of centrifugal force.
The relationship between the pulsar density (p) and period (P) is 3π/P^2xG, and G is the gravitational constant.
Calculating with the pulsar period in the Crab Nebula as 33 milliseconds, the density obtained is 10^11g/cm^3, which is greater than the density of the white dwarf; then, the current fastest rotating pulsar period is calculated as one millisecond, then the density It is 10^13g/cm^3.
Close to the estimated density of a neutron star.
"give!"
"It's done." Xu Mang handed the answer to Du Yuan.
Du Yuan: Σ(っ°Д°;)っ
God!
Is he really Einstein reincarnated?
"Ahem!"
"Professor!" Taking Xu Mang's answer, Du Yuan shouted to the professor: "I have proved it."
"???"
"???"
"???"
Damn it!
Who is this guy?
Are you really an auditor?
Everyone stared at Du Yuan, only Xu Mang looked at the incandescent lamp on the ceiling with a dull expression.
The professor hurriedly came to Du Yuan, looked at the answer in his hand, carefully watched for more than 30 seconds, and said seriously: "Classmate... are you sure you are in the mathematics department? Will you have amnesia? Actually you Is it from the Department of Physics?"
"..."
"Professor, I really came here to listen." Du Yuan said helplessly: "Is the proof right?"
"perfect!"
The professor smiled and said, "I can't imagine that there is a genius among the auditors."
With emotion,
The professor returned to the podium and continued to lecture.
"Neutron stars are not only dense, but also very strong magnetic fields. Let's take the sun as an example to compress the sun into a neutron star. Of course... under natural conditions, this may not be true, because after the sun collapses, only white dwarfs can be formed."
"If the sun compresses the neutron star, then its magnetic field strength will be..."
When the professor said this, he suddenly remembered that there was a genius in his class, and smiled: "The genius student sitting in the last row, please go to the blackboard to calculate the magnetic field transition between the sun and the neutron star."
Du Yuan was stunned. He didn't even know the strength of the sun's surface magnetic field. How could he calculate the magnetic field conversion between the sun and the neutron star.
The previous two pretends were completely dependent on the answers provided by Xu Mang.
just now...
It is necessary to calculate in front of everyone, this is not forcing people to hang themselves!
Sure enough, pretending to be risky!
"I..."
"This..." Du Yuan, a fake astrophysics genius, no longer knew what to do.
"Classmates!"
"Everyone is waiting for you, please hurry up and don't waste everyone's time." The professor said with a smile, "It's not difficult for you."
Xu Mang glanced at the poor man who was forced to hang himself, and said helplessly: "Remember... Conservation of magnetic flux means that the magnetic field lines on the surface of the star will be compressed. Calculations are carried out according to this concept."
Hearing Xu Mang's words,
Du Yuan was even more desperate.
Brother!
I don't understand!
"Classmates!"
"Don't dawdle, come up soon!" the professor urged.
No way~EbookFREE.me~ Du Yuan could only stand up in silence, but his heart was suffering.
Just as he was about to take this difficult step, Du Yuan suddenly awakened. Instead of being exposed on the spot, the truth now became clear. He then pointed at Xu Mang and said with shame: "Professor...I confessed... the previous two times. The answer was given to me by this person, but I don’t know anything."
_(°Д°)/Professor, I reported it, he did it!
Σ(｀д′ノ)ノ Fuck, are you two or five? !
Words fall,
There was another uproar in the classroom.
what's the situation?
The twists and turns!
The plot is confusing...you can't understand it.
......