Chapter 319: Its really a big deal (Part 1) (9.4K)
"...."
In the activity room.
Seeing someone raising their hand to speak, Xu Yun smiled slightly and prepared to ask the other person to express his opinion.
In this situation, regardless of whether the words are right or wrong, the attitude should be encouraged.
But after seeing clearly the faces of the members who raised their hands this time.
He was stunned for a moment, the words he was about to say stopped at the corner of his mouth, and he subconsciously glanced at Lao Tang from the corner of his eye.
This member is a well-proportioned young man with shoulder-length blond hair, a high nose, and regular facial features.
Even in terms of Eastern aesthetics, this man can be called handsome.
Xu Yun also remembered the other party's name very clearly, it was Ralph Ashley.
However, Xu Yun was able to remember this name, not because the other party had any amazing achievements later, nor because the name had the same pronunciation as that of a later young film actor named Ashley.
It's because this person's 'identity' is so special.
Mentioned it before.
There is only one direct reason why Frederick Agar Ellis ran against Lao Tang for President of the Federation of Students:
Ellis's favorite roommate in the dormitory, someone who was always ranked second in the mathematics department, was pursuing Lao Tang, which led to a feud between the two.
That's right.
That person is...
Ralph Ashley. (True story, the reference is "Age the Earth: Lord Kelvin's Model", author Joe D. Burchfield, the original picture of the quoted letter is on page 47 of the 93rd edition of Oxford Press, but it is not in Lao Tang's history
Ran for president)
A love triangle between three men...
Of course.
Among the three, Lao Tang's orientation was normal. He later married a girl named Margaret. He was an unlucky guy who was targeted by male ketone.
On Pluto Night three months ago, Ralph Ashley was naturally there to cheer.
And I submitted my application for membership early.
In fact, at the beginning, Xu Yun did not want to call Ralph Ashley into the Gewu Society.
However, the other party had contributed a lot in the previous preparation process of the calculation team, and many subsequent matters were quickly resolved through his connections.
In addition, Xu Yun had chatted with this person several times and felt that he did not display any strange attributes in normal times, so he discussed with Lao Tang and included him in the Gewu Society.
Ralph Ashley's performance is still pretty good these days, but when he speaks, Xu Yun will more or less reflexively think of Lao Tang...
Then he took a deep breath and adjusted his emotions to normal.
Turning his head, he said to Ralph Ashley:
"Senior Ashley, what do you think?"
Ralph Ashley stood up after hearing this. With a solemn expression and handsome appearance, there was no hint that this person was a Chen Yuanyuan type of 'disaster':
"Classmate Luo Feng, I do have some ideas that I'm not sure are correct, and I hope you can give me some advice."
"In my opinion, since we want to verify the speed of light in the direction of ether movement and the speed of light measured in the direction perpendicular to the movement, the first thing we need to determine is the choice of light source."
"This light source must not be too large, and its various properties must be known and controllable, so I recommend using a sodium light source."
Xu Yun nodded and expressed his affirmation.
In fact, in the experiment he designed...or carried, the most suitable one was the vacuum tube light source.
But at the moment, Ralph Ashley doesn't know that Faraday has already tinkered with this thing. He can think of the sodium light source as already very good.
Students who often hang out in the laboratory in future generations should all know this.
Sodium light source is a basic optical instrument and experimental light source in measurement.
It has double lines with two wavelengths, 589.0 and 589.6, and the color is relatively bright.
when the level of technology is low.
Sodium light source is the most readily available monochromatic light source.
It is clear.
This handsome guy, who doesn’t know whether he is 0 or 1, has a passable knowledge reserve in natural sciences.
So Xu Yun paused and asked again:
"Senior Ashley, besides the sodium light source, do you have anything else to add?"
Ralph Ashley smiled slightly, glanced at Lao Tang sitting beside him calmly, and said:
"The second point is..."
"If the ether exists...I mean it exists, and the propagation of the speed of light in the ether obeys the Galilean speed superposition principle."
"Then the instrument we designed must have two optical path directions in the experimental coordinate system."
This time, not only Xu Yun, but also other members in the audience nodded together.
Galilean velocity superposition is one of the core principles of classical physics.
Assuming that the ether is stationary relative to the sun, then the instrument is moving - and its speed is the revolution speed of the earth.
Having said this.
Ralph Ashley also frowned slightly, spread his hands neatly, and said to Xu Yun:
"Classmate Luo Feng, this is all I can think of. As for the other steps... I have no idea."
Seeing this, Xu Yun applauded and praised:
"It's okay, Senior Ashley, you have done a very, very good job."
Xu Yun's words were indeed not polite. If he could think of the first two points, Ralph Ashley's ability was worthy of his second place in the mathematics department.
Xu Yun then turned around and drew a small dot on the original location of the earth.
The English word "sodium" is marked to indicate that this is a sodium light source.
Then an arrow is drawn from the light source, representing the light path, which is divided into two directions in a certain area.
fantuan.
Finish drawing these.
He put down the chalk again, looked at the people in the audience, and asked:
"Dear students, in addition to the above two points, do you have any other ideas?"
"This is not a classroom, everyone can speak freely."
Hearing Xu Yun's words.
Buzz buzz——
In the activity room of more than thirty people, discussions like a vibrating egg soon sounded.
"I think it's possible to add a lens to the left light path?"
This chapter is not finished yet, please click on the next page to continue reading the exciting content! "....Isn't it appropriate? Do you want to spread the color?"
"How about adding a switch like a small door here?"
A few minutes passed.
Hubert Airy raised his hand. The son of the director of the Greenwich Observatory had an expression on his face that was eager to try, as if he had thought of some feasible method:
"Classmate Luo Feng, here!"
"Please tell me, Airi-san."
Hubert Ally stood up from the audience and said quickly:
"Spectroscope, classmate Luo Feng, I think there must be a spectroscope!"
As he spoke, he stretched his left index finger horizontally to indicate the light path.
The palm of his right hand was bent outward at 45 degrees, indicating:
"You see, the light moves from left to right. Since it is a point light source, there is no bifurcation."
"So we can place a beam splitter on the right side of the light path to split the light path into two beams of light that are perpendicular to each other."
"In this way, two beams that meet the experimental requirements are formed!"
Hear about his designs.
Before Xu Yun could say anything, another boy asked first:
"So, Mr. Airy, what happens after the light is divided? How do we observe or calculate the difference between the two beams of light?"
Hubert Ally was stunned when he heard this, opened his mouth, and couldn't help but hesitate:
"This...there should be some kind of phenomenon, right?"
The questioner did not let him go, but asked further:
"Then what do you mean?"
Hubert Airey.
You can see it.
This young man also raised his hand when his mind was hot. Although his idea was fine, he obviously only considered the first half and was eager to show off.
But after all, Hubert Airy had a good relationship with Xu Yun, and his father, George Bedell Airy, also helped crucially during Pluto's Night.
Therefore, Xu Yun took the initiative to help Hubert Airy out of trouble:
"Ahem...let me say a few words."
"Although Airy did not come up with a complete idea, the idea of the spectroscope is very good."
Then he picked up the pen and prepared to draw a diagram on the blackboard:
"Actually, we only need to add two reflectors at the end of the two bifurcated light paths."
"Then place an observation screen on the other side of the vertical light path, and you can see on it..."
"Okay, I get it now!"
As a result, before Xu Yun finished writing, a figure appeared on his left side and said excitedly:
"It's interference, it's interference stripes! Am I right, Mr. Luo Feng?"
Although he could not clearly see the appearance of the interrupter, Xu Yun was already so familiar with the voice that he could no longer be familiar with it.
At the same time, looking at the more than thirty people in the classroom, there is only one person who would call him "Mr. Luo Feng":
The protagonist of this dungeon is the future Fu Qing Wuwei Xubo Taishang Cihuang Daojun, classmate Xiaomai.
Seeing that Xiaomai seemed to have an idea and was more confident than Hubert Airy, Xu Yun suddenly had another thought in his mind:
or......
To what extent can you consider trying wheat?
After all, he realized that although Xiaomai kicked history forward a few times with a few "Ah Lielie", Xu Yun had never seen Xiaomai actually design a complete experiment.
This is indeed a pity for Xu Yun, who likes to get achievement points when playing games.
Now that you have the opportunity, how can you let it go?
So he turned around, waved to Xiaomai, and motioned him to come to the podium:
"Come on, come on, I'll give you the pen and you can write."
Xiaomai walked to the stage naively, took the chalk, and confirmed to Xu Yun:
"Mr. Luo Feng, do you really want me to write it?"
Xu Yun stepped aside and made a gesture of invitation:
"Start your show."
Seeing this, Xiaomai no longer hesitated, took a step toward the middle, and started writing on the blackboard:
"As you can see, the light emitted by the point light source will be split into two beams of light after passing through the beam splitter."
"Well... for the convenience of description, let's call it beam 1 that travels horizontally to the right, and call it beam 2 that refracts toward the top of the blackboard."
"Here's what I think."
"We can place a reflector at the end of each of the two light beams. In this way, just like Mr. Luo Feng did when he measured the speed of light, the two lights will be reflected after hitting the reflector and return to the spectroscope in the direction in which they came from."
"Then place another observation screen on the other side of the vertical light path...that is, under the blackboard."
"Then light beam 1 will first be reflected by the reflector M1, and then projected to the observation screen through the beam splitter."
"The same applies to beam 2. It is reflected by the reflector M2 and then projected to the observation screen through the beam splitter, causing interference with beam 1..."
Wheat's ideas were obviously much more complete than Hubert Airy's. From the moment he started writing, the chalk he held never stopped.
Everyone in the audience, whether they were freshmen, seniors or third-year graduate students, watched Xiaomai’s demonstration attentively.
Da da da--
The entire activity room was silent, with only the sound of the contact of chalk and blackboard and the sound of Xiaomai's explanation. Even Xu Yun stepped aside:
"... Then we rotate the entire experimental instrument 90 degrees, so that the time when beam 1 and beam 2 arrive at the observation screen are interchanged, causing the interference fringes that have been formed to move."
"When the whole instrument is slowly rotating and taking continuous readings, if our equipment is very accurate, it should be easy to measure the movement of the stripes..."
"...If the interference fringes move, and the distance of movement of the fringes is measured from the experiment, the speed of movement of the earth relative to the ether can be found, thereby confirming the existence of the ether."
Mentioned earlier.
Except for Bruch, most of the members on site were lovers of natural science.
Although the purity and depth of knowledge they mastered cannot be compared with that of their peers in later generations, they still possess basic scientific literacy.
Therefore, as Xiaomai's writings gradually filled up the blackboard, some members in the audience gradually showed astonished expressions on their faces.
Many people even took out their notes, recorded the plan, and calculated the numerical values.
This chapter is not finished yet, please click on the next page to continue reading the exciting content! That’s right.
Presumably some students who are not ashamed have also noticed it.
The experiment designed by Xu Yun under the guidance of Gewu Society was one of the two famous dark clouds of physics in the 20th century...
Michelson-Morley experiment!
This is a famous experiment conducted by Michelson and Morey on the Eagles in 1887. Its idea is actually very simple, which is what Xu Yun said before:
If there is ether, then when the earth passes through the ether and revolves around the sun, the speed of light measured in the direction of the movement of the earth through the ether should be greater than the speed of light measured in the direction perpendicular to the motion.
So,
Michelson and Morey came up with such an experimental device.
The instruments used in this experiment are not complicated. From the top view, they are divided into four modules:
The light source is located on the far left side of the top view, and the light path is emitted from left to right - in actual operation, this direction must be consistent with the direction of the earth's revolution.
There is a spectroscope placed on the right side of the light source.
As the name suggests, a spectroscope is a mirror that can separate light, also called a beam splitter.
It is classified from the nature of the material as a kind of coated glass, which is coated with one or more thin films on the surface of optical glass.
When a beam of light is projected onto the coated glass, the beam is divided into two or more beams through reflection and refraction.
The spectroscope used in Michelson-Morley's experiment requires very high precision. It can divide the light into beam 1 that continues to the right, and beam 2 that goes vertically upward - also from a top view.
Then two more reflectors are placed at the ends of beam 1 and beam 2. After the light arrives, it will return to the original path.
Said it earlier.
When the earth revolves, there will be an "ether wind" blowing in the face, and this speed is 30 kilometers per second.
Therefore, the propagation speed of beam 1 along the revolution direction when arriving at M1 and returning from M1 is different.
Assume that the speed of the earth is v, and the distance from the beam splitter to the reflector is d.
Then the past and return speeds are c-v and c v respectively, which is equivalent to headwind and SF Express.
The round trip time between the two is:
d/(c-v) d/(c v).
Since Beam 2 is perpendicular to the direction of the Earth's rotation, it will encounter the ether wind whether it comes or returns.
Then the time is fixed:
2d/√(c2-v2).
This way.
The optical path difference between beam 2 and beam 1 reaching the observation screen is:
c(d/(c-v) d/(c v)-2d/√(c2-v2)).
If there is an optical path difference, they will definitely produce interference fringes.
Then, as long as the experimental instrument is rotated 90 degrees as a whole, the time when beam 1 and beam 2 arrive at the observation screen will be interchanged, causing the interference fringes that have been formed to move.
The amount of this change is also easy to calculate. I learned it in high school physics, and it is △l=2dv2/c2.
This way.
The number of moving fringes is △l/λ.
The length of the light arm of the interferometer designed by Michelson at that time was 12 meters, and the final fringe that should theoretically move was 0.37.
As for the result...
Put it this way.
The purpose of Michelson-Morley's experiment was to prove the existence of ether. Michelson and Morley were also firm supporters of ether theory.
In the history of physics, this experiment is also called the small Poisson experiment...
Seeing the word Poisson, everyone must have guessed the final result.
That's right.
Let alone 0.37, the stripe didn't move at all.
The experiment that was supposed to prove the ether actually killed the ether.
Therefore, this experiment is one of the major nodes in the history of physics, and it is also another experiment that will be mentioned by those who deny the theory of relativity in later generations:
However, compared with Fizeau's running water experiment, which serves as the "theoretical fulcrum" of civil science, the Michelson-Morley experiment often acts as a clown in the eyes of civil science.
Standard terminology generally looks like this:
[The reason why the Michelson-Morley experiment has 0 results is because this experiment is completely wrong and it has no meaning...].
This kind of treatment is a bit like Yuan Shu, the Skeleton King in the Three Kingdoms. Basically, when mentioning this person, one cannot escape from the phrase "withered bones in the grave..."
But actually.
A lot of people have dissed these things that civilian scientists have questioned in the history of physics.
For example, after the results of the Michelson-Morley experiment were announced, many people believed that the experiment was not conclusive.
For example, the famous Lorentz once still had doubts about the negative results of the experiment.
In a paper published in 1892, Rayleigh believed that "whether the ether on the surface of the earth is absolutely stationary or relatively stationary" is still an open question.
He felt that the negative results of the Michelson-Morley experiment were "a really disappointing thing."
Oh, by the way, there is also Lao Tang who was targeted by male ketone at the scene today.
This Lord Kelvin did not believe this result, just like Liu Bei who learned that Guan Yu was dead, he shouted, "Impossible, I am invincible in the world".
At the International Physics Conference in Paris in 1900, he even directly urged Morey and another physicist named Miller to redo the experiment, otherwise they would be sued...
During the period from the announcement of the results of the Michelson-Morley experiment to the publication of the theory of relativity by Lao Ai.
Scientists have repeated the Michelson-Morley experiment countless times in different places and at different times.
Various means are used to verify the experimental results, and the accuracy is continuously improved.
However, the result remains unchanged.
The interference fringes seemed to be suppressed by the roots of my ears, and I remained motionless.
After discovering that the experimental results were unchanged, physicists began to look for the shortcomings of the experiment, but still to no avail.
It can be said like this.
Looking at the history of physics, you can't find a few experiments like the Michelson-Morley experiment, in which the entire physics community spent 20 years trying to find bugs.
in this case.
If future generations were to find fault with some unknown substance or from a microscopic perspective, it would be easier to explain.
This chapter is not finished yet, please click on the next page to continue reading the exciting content! But those civil sciences directly deduct it from the words, such as why it takes one-fifth of the light path less, and there is no relative origin, etc. - these are actually
It has been studied by the physics community countless times. (To complain about Douyin’s algorithm, I recently read a few civil science bloggers, and now their homepages are all about civil science. It really makes people have high blood pressure...
..)
There is only one thing that Min Ke really said right, that is, the constant speed of light proposed by Lao Ai is indeed just a hypothesis and not a principle.
But the problem is that although this hypothesis has no real experimental proof that can be conclusive, it has not failed in debates with other theories.
At least in Xu Yun's opinion.
After a hypothesis is generally accepted, when it is applied, it is actually no different from a principle.
In many situations, picking out words is a very boring behavior.
Just like purified water and mineral water are two different concepts, but when you ask your friend to buy a bottle of mineral water and he buys a bottle of purified water, you tell him that you bought the wrong water and try it?
If you really say this, your friends will leave you sooner or later.
His eyes returned to reality.
Looking at the dense writing on the blackboard, Xu Yun glanced at Xiaomai with a silly smile on his face.
I couldn't help but feel a surge of emotion in my heart.
As expected of a wall hanging who can derive Maxwell's equations, his mathematical sensitivity is really too strong.
To know.
Although the equipment of the Michelson-Morley experiment is simple, it is not easy to figure out the changes in interference fringes.
It can only be said that during this period, under the training of Xu Yun and Gauss, Wheat's growth rate reached an extremely terrifying level.
Otherwise, based on Xu Yun’s understanding of wheat.
At least in the original history, Maimai during this period should not have been so stupid - after all, he had only entered Cambridge for less than half a year, and he was just a stupid youth version.
But on the other hand.
Wheat's writing on the blackboard actually saved Xu Yun some things, and many processes were even simpler than Xu Yun expected.
So he patted Wheat on the shoulder, motioned the tool man to return to his seat, and picked the peach himself.
Then he looked at the people in the audience and said:
"Dear students, as you can see, Maxwell's demonstration is perfect - yes, this is the experimental plan I originally prepared."
"If I have to add anything, it is that the spectroscope must be placed on a smooth marble plate, with the bottom filled with mercury, so that it can be controlled and turned smoothly."
"Other than that, even if Mr. Fat Fish is reincarnated, there is nothing to add."
There was a sudden silence in the audience.
A few seconds later.
Bang bang bang——
The activity room suddenly burst into warm applause, and many people even had a look of pride on their faces.
In this timeline, a fat fish descendant like Xu Yun can make such an evaluation, which is basically no less than later generations Pele and Manadona simultaneously saying that a certain player has the appearance of a ball king.
After the applause subsides.
Max Christian Friedrich Bruch, who was not too embarrassed to watch the excitement, raised his hand again and asked impatiently:
"Classmate Luo Feng, when can we start this experiment?"
Xu Yun smiled when he heard this, made a calm gesture toward him, and said:
"Student Bruch, don't be too anxious. Although this experiment is simple, the equipment required is very demanding."
"For example, a convex lens used to spread the light spot to form an interference pattern, with a length of at least 12 meters, an interferometer cantilever that can detect 0.01 times the wavelength change, etc..."
"The above equipment can be prepared within half a year, which is considered fast."
"Not to mention that debugging also takes a certain amount of time, so my initial experimental time is probably around October this year."
As Xu Yun said.
Historically, the reason why Michelson found Morey to cooperate was because the equipment required for this experiment was somewhat out of scope.
The Morey's full name was Edward Morey. He was an expert in building experimental equipment, and his skills were second to none at the end of the 19th century.
But even if Morey took action himself, it took them four years to get many instruments.
At present, due to the influence of Xu Yun, the industrial productivity of optical equipment is close to 1900, which is higher than that of Michelson and others.
At the same time, with Aveline as an ATM girl spreading money, it shouldn’t be difficult to complete the preparations within half a year.
Of course.
The set of instruments prepared by Xu Yun was aimed at those authorities, but the Gewu Society could build a simple interferometer for the members to try out first.
Although it is easy to find some 'loopholes' in the simple interferometer, it can shake the confidence of these club members in the 'ether' to some extent - otherwise, if they wait for half a year, some links within the club may encounter resistance.
So Xu Yun thought for a while and added:
"Dear students, although a sophisticated large-scale interferometer takes several months, it will be difficult to see the finished product for a while."
"But if everyone is interested, the association can provide you with a set of simple experimental equipment."
"This equipment may have some loopholes in theory. The optical arm is only about one meter. It can be completed in about a week. I don't know if you are willing..."
Before the last word "meaning" was finished, the audience began to murmur:
"Of course I do!"
"I want it, I want it, it doesn't matter if it's shorter, the light path is the same thickness anyway..."
"Let's fix it!"
Three minutes later.
Xu Yun's proposals were all approved.
After all, for students of this age, it would be great if the club can provide opportunities for experimentation.
As for the concept of accuracy, at least before the experiment begins, they will never care.
As for after the test...
I would probably pull up my pants and look like a normal person.
After appeasing everyone's emotions.
Xu Yun looked around the audience for another week and looked at Hubert Airy:
"Classmate Airy, I wonder if you still remember what I said to you earlier?"
Hubert Airy winked:
"Ten points from Gryffindor?"
"...."
Xu Yun glanced at this guy speechlessly, shook his head and said:
"When you mentioned the attributes of light before, I told you that the second half of your sentence was actually wrong."
"That half of your sentence also includes another concept besides ether."
"That is to say, although light seems to have wave-particle duality, it will only show one property under a fixed situation."
"For example, Newton's bright spots, and the photoelectric effect."
Hearing what Xu Yun said, Hubert Airy also remembered this:
"Oh...I remembered, yes, you said this."
After saying that, he suddenly realized something, looked at Xu Yun in surprise, and said uncertainly:
"Classmate Luo Feng, could it be..."
"Besides interfering with the experiment, do you have other arrangements?"
Xu Yun nodded towards him, a playful smile suddenly appeared at the corner of his mouth, and said to everyone in the audience:
"Dear students, I wonder how your craft work is going?"
