I Don’t Want to Win Lying Down

Accompanied by this classmate, Xu Mang came to a certain classroom in the physics department building, but he found a problem. This guy didn't bring any books. There were about sixty people in the classroom, and a dozen of them didn't have any books.

What's the situation?

Does this major accept scumbags?

brother?

Why didn't these people bring books? Xu Mang asked curiously.

An observer. The little brother said indifferently, It's about the same as you.

...

What about you? Xu Mang asked with a dark face.

I?

Of course I am also an observer. The little brother smiled: But I am better than them, including you, in astrophysics.

Fuck!

Met a poser!

Good guy... How dare you pretend to be aggressive in front of me, Xu Mang?

Xu Mang was so angry, he always used his routine to trick others, but today he was given a trick by someone else. The problem was that he was given a trick by a graduate student. This was the biggest stain in the history of his routine.

well!

Does your family know that you are so awesome? Xu Mang asked helplessly, Good guy... You are obviously an auditor like me, how did you pretend that you are an astrophysics major?

...

You can't say that. The brother smiled wryly, I might be a little better than you, of course...I mean possible.

Dare you ask where the brother is sacred? Xu Mang asked.

Du Yuan.

Oh... Xu Mang nodded, and said silently, Do you know who I am?

Du Yuan was stunned for a moment, and said calmly: It doesn't matter who you are to me, you just met by chance, maybe after tomorrow, we won't have any intersection, so it's okay if you don't know the name,

Less concern, more obsession.

Xu Mang: (°ー°〃)

hell!

Meet a well-matched opponent.

I feel like he's mentally ill.

soon,

A rather dignified professor walked in, without calling names or anything, and started the class directly.

Today we will mainly explain the physical properties of neutron stars. Although this professor is short-tempered, he has a wealth of knowledge, which can be inferred from his hairstyle and volume. After all, he is extremely smart.

When a massive star evolves to a late stage, it will accumulate a huge iron core through nuclear combustion. When the iron core reaches a certain mass, it will collapse due to excessive pressure, resulting in violent gamma-ray bursts and supernova explosions. And a neutron star was born.

In fact, a neutron star is an ultra-dense star composed of neutron matter. How high is the density of a neutron star? I will give you five minutes to estimate the density of a neutron star. First, the mass of a neutron star is about the same as that of the sun, and its 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 seriously: Start to count, the time is five minutes.

Soon everyone began to count. Of course, there were a dozen or so auditors who were paid for nothing, silently sitting in their seats, waiting for the announcement of the answer.

Xu Mang looked at the tense calculations of the students present, and couldn't help feeling a little confused, and asked curiously, Oh...is this a freshman?

How do you know? Du Yuan said in surprise, It's indeed a freshman.

...

I don't even know the quick conversion between two stars with the same mass. What do you mean if it's not a newborn? Xu Mang said helplessly: When two stars have the same mass, their density is inversely proportional to the cube of the radius. .”

Du Yuan froze for a moment, then said suspiciously: Are you sure?

...

Are you doing research in the astrophysics group? Xu Mang asked, Don't tell me, you are only in charge of calculations?

Du Yuan nodded awkwardly: Then do you know the density?

Do you have a pen and paper?

have!

I don't know where Du Yuan took out the pen and paper and handed them to Xu Mang.

less than ten seconds,

Xu Mang 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 in horror, and asked cautiously, Brother... right?

Try it. Xu Mang shrugged and said calmly.

The reason why Xu Mang gave up the answer was because he didn't want to bear the title of autism maker anymore, and he wanted to give this title to Du Yuan.

Du Yuan thought about it, raised his hand hastily, and shouted at the professor: Professor, I'm done!

As soon as the voice fell,

It caused an uproar.

Who are you...

An auditor? The professor saw Du Yuan and saw that there were no textbooks on his desk, so he knew that this person was here to audit.

En! Du Yuan nodded.

immediately,

The professor came to Du Yuan's side, glanced at his answer, and couldn't help but praise: Which department are you from?

Department of Mathematics...

I'm a graduate student, and I happen to be in the astrophysics research group, responsible for the calculation program. Du Yuan said seriously: In order to strengthen my business ability, I came here to listen to your lectures. I have been listening to your lectures. Keep it all in mind.

Xu Mang: (￣△￣;)

talent!

No,

This is a wolf off.

good!

It's good to be self-motivated, keep working hard. The astrophysics professor nodded repeatedly.

Immediately afterwards,

The professor returned to the podium and continued his lecture.

...

...

Xu Mang looked at Du Yuan, Du Yuan looked at Xu Mang, neither of them spoke.

brother!

You're so fucking awesome! Du Yuan said to Xu Mang with admiration, Don't say anything, I'll treat you at noon.

Xu Mang smiled wryly, You...how did you get into Nantah University?

I'm pretty good at mathematics, but I don't know anything about astronomy. Du Yuan sighed: If it wasn't for the purpose of messing with a thesis, why would I study astrophysics?

...

Thanks for your hard work.

at this time,

The professor posed another problem.

A pulsar is a neutron star that rotates at a high speed. The pulsar rotates very fast, and some can even reach more than a thousand revolutions per second. Such a fast rotation, coupled with the magnetic field and extreme conditions, will cause the two poles of the pulsar to be aligned. Sexual electromagnetic radiation.

Here is a question for you. Who can use digital calculations to prove that a pulsar is a neutron star? the professor asked, Think about it.

Xu Mang sat in the last row, watching everyone's bewildered expressions, just like when he was in the past.

actually,

Astrophysics is a brand new major that can only be accessed in colleges, and only in top universities. These students are also unlucky... High school doesn't teach these things at all.

It means that everyone starts from scratch. In addition to the professor's teaching, they also need other channels to acquire knowledge, otherwise they will definitely be eliminated.

Paper and pen! Xu Mang said.

oh...

Du Yuan hurriedly handed it to Xu Mang.

soon,

Xu Mang used simple Newton's law of universal gravitation and centrifugal force formula to give a calculation proof that a pulsar is a neutron star. In fact, he only needs to master one concept. The centrifugal force of the pulsar is less than the gravitational force, otherwise the pulsar will disintegrate.

According to this concept, very detailed calculations can be carried out through the law of universal gravitation and the formula of centrifugal force.

The relationship between its pulsar density (p) and period (P) is p\u003e3π/P^2xG, G is the gravitational constant.

Calculated by taking the period of the pulsar in the Crab Nebula as 33 milliseconds, the obtained density is 10^11g/cm^3, which is greater than the density of white dwarfs; and then calculated by taking the period of the fastest rotating pulsar as one millisecond, then the density It is 10^13g/cm^3.

close to density estimates for neutron stars.

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! Du Yuan took Xu Mang's answer and shouted at the professor, I've proved it.

???

???

???

Fuck!

Who is this guy?

Are you really an auditor?

Everyone stared at Du Yuan, only Xu Mang stared at the incandescent lamp on the ceiling with a dazed expression.

The professor hurried to Du Yuan's side, looked at the answer in his hand, looked at it carefully for more than 30 seconds, and said seriously: Student... Are you sure you are from the Department of Mathematics? Could it be that you lost your memory? In fact, you From the physics department?

...

Professor, I really came here to listen. Du Yuan said helplessly: Is the proof result correct?

Perfect!

The professor smiled and said, Unexpectedly, there is a genius among the auditors.

In addition to emotion,

The professor returned to the podium and continued lecturing.

Neutron stars are not only dense, but also have a very strong magnetic field. Let's take the sun as an example and compress the sun into a neutron star. Of course...under natural circumstances, this may not be true, because after the sun collapses, it can only form a white dwarf.

If the sun compresses the neutron star, its magnetic field strength will be...

When the professor said this, he suddenly remembered a genius in his class, and said with a smile: The genius student sitting in the last row, go to the blackboard and calculate the magnetic field conversion 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 acts of coercion were all based on the answers provided by Xu Mang.

Now...

To calculate in front of everyone, isn't it forcing people to hang themselves!

Sure enough, pretense is risky!

I...

This... Du Yuan, a fake astrophysics genius, no longer knew what to do.

classmate!

Everyone is waiting for you, please hurry up and don't waste everyone's time. The professor said with a smile: This is not difficult for you.

Xu Mang glanced at the poor man who was forced to hang himself, and said helplessly, Remember... the conservation of magnetic flux means that the magnetic field lines on the surface of a star will be compressed, and the calculation is based on this concept.

Hearing Xu Mang's words,

Du Yuan was even more desperate.

Brother!

I don't understand!

classmate!

Stop dawdling, come up quickly! the professor urged.

no way,

Du Yuan could only get up silently, but his heart was tormented.

Just about to take this difficult step, Du Yuan suddenly woke up. Rather than being exposed on the spot, the truth is better now. Then he pointed at Xu Mang and said with shame on his face, Professor...I confess...the two times before... The answer was given to me by this person, but in fact I don’t know anything.”

_(°Д°)/Professor, I reported it, he did it all!

Σ(｀д′*ノ)ノ What the hell, are you a jerk? !

words fall,

There was another uproar in the classroom.

what's the situation?

There are twists and turns!

This plot is complicated and confusing... I can't even understand it.

 …