Page 83
Everyone's eyes naturally focused together, and Lin En's figure soon appeared in front of everyone, with a faint smile on his face. "Ladies and gentlemen, welcome to take the time to attend today's magic seminar."
The seminar hall, which had been a bit noisy to begin with, immediately became as boisterous as a festival celebration, with all kinds of discussions and some people even shouting loudly.
"Mr. Lin En, I still don't understand a few things about the method you proposed to measure the angle between the earth's center and the center of the earth. In addition, what do cube, square and square root mean?"
"What is the radius and volume of the planet beneath our feet? Is it 860 billion cubic kilometers or 1.23 billion cubic kilometers?"
"Mr. Lin En, when you mentioned weighing a planet, did you use some special magic? Or is it the same division method as measuring the circumference?"
Various questions came one after another. In addition to those wizards who were curious about the weighing method, there were also some wizards who wanted to confirm whether the values they calculated were correct.
Although math is not difficult for wizards with good brains, the degree of mastery varies from wizard to wizard. In addition, the data of a planet is too large. If there is even the slightest mistake in the calculation process, the final result will be very different.
So after two days of fermentation, thousands of wizards calculated several different answers and almost fought on the spot to argue about who was right and who was wrong.
"Silence... Silence! Now is not the time for questions!" A great wizard who was hosting the seminar slammed the table angrily, which temporarily stopped the increasingly loud discussions.
Lin En spoke at this time. "I will answer your questions one by one."
"First of all, the radius of the planet beneath our feet is about 6,875 kilometers, and the volume is 1,361.4 billion cubic kilometers. We can use the circumference formula to reverse the radius. The radius is equal to the circumference divided by twice the value of pi, and the volume can be directly calculated by substituting the radius into the formula..."
Lin En patiently explained the radius, volume, and the corresponding Olympiad mathematical formulas and derivation processes. After all, these are the data that must be used in subsequent experiments.
Those wizards who calculated the data accurately were naturally very proud, while those who calculated incorrectly looked embarrassed. Some wizards who were unwilling to accept the result even checked the calculation on the spot.
However, there were also many wizards like Roll who had average counting skills and secretly memorized these data in their minds.
You should know that recently, planets and star orbits have been the hottest topics in Greenrill. Any gathering of wizards will inevitably talk about them, and it has become a trend.
"As for the weight of the planet beneath our feet and how to measure it? I think there is still an important problem that needs to be solved before we can truly decipher it!" Lin En straightened his face, looked at the wizards in the seminar hall, and suddenly asked.
"What do you think is the nature of gravity? Or what factors determine how much an object weighs when it is weighed?"
Lynn's question instantly stumped the wizards on the field. It looked simple yet very tricky, even a little inexplicable, as if asking them to explain why water is called water instead of soil!
The weight of an object is of course measured using a balance scale and weights. The wizards of the Alchemy Association have even created a magic scale that can weigh an object very accurately.
"What you want to say is that the gravity we feel is the gravity of the planet itself, right? So, it is because of the influence of gravity that we can weigh an object?" After pondering for a while, a great wizard in front of the platform responded.
"Yes, but no!" Lin En nodded, then shook his head. "Gravity is a component of universal gravitation. It is not always a constant value. Even on the same planet, the gravity felt in different places will be different..."
"Generally speaking, the closer you are to the planet, the greater the influence of gravity, and the farther you are, the smaller the influence of gravity. Once you enter the boundless starry sky, the concept of weight no longer exists!" Lin En explained.
"That is to say, in a place without gravity, everything is weightless?" The witch sitting in the front row couldn't help but stand up. "This... is incredible!"
Although the concept of gravity has been proposed long ago, and after the baptism of free fall experiments, the relationship between gravity and gravity is almost equal, but the fact that the weight of an object will change or even disappear with the change of the strength of gravity is still far beyond everyone's imagination.
This is simply challenging their three views!
After a while, another wizard stood up and refuted. "Mr. Lin En, please forgive me for not agreeing with this concept. Doesn't it mean that no matter whether it is soil or gold, silver, copper or iron, once they are free from the influence of gravity, they will become lighter than a feather?"
"Of course they are different, because their masses are different! And the weight we feel is actually the product of the mass of the object and the acceleration of gravity!" Lin En said freely.
"Mass, what is that?" The witch who had just stood up had a puzzled look on her face.
"You can think of it as the total amount of elements contained in an object!" Lin En said as succinctly as possible. "It is the most basic property inherent in matter itself, and it does not change with the temperature, pressure, or speed of the outside world... Whether it is placed on a planet or in the universe, this value is the same!"
The discussion in the hall became heated again, and the topic of discussion was the new concept proposed by Lynn, using mass instead of weight.
Everything in the world is made up of elements. This is common sense in the wizarding land, so Lin En’s words are not too difficult to understand.
However, the other party's next words shocked everyone present.
"In addition, in my opinion, gravity may not exist!" Lin En didn't care whether these wizards could accept it or not, and he started to make explosive arguments as soon as he opened his mouth!
The scene of the seminar suddenly exploded. Thousands of wizards stood up and looked at Lin En in disbelief - he actually denied the existence of gravity!
How dare he? !
Chapter 158 Matter tells space-time how to curve, and space-time tells matter how to move
Lin En's words instantly ignited the entire audience, and even Raphael and others who were responsible for maintaining order at the seminar became a little restless.
If Lin En's previous remarks were undermining the foundation of the magic world, then now he is trying to knock down the entire magic building with one foot!
"Mr. Lin, this is not the time to joke!" Raphael looked at Lin with a serious expression. "Don't the free fall law and the theory of stellar orbits you proposed earlier prove the influence of gravity?"
Raphael really didn't understand why the other party suddenly said such outrageous words. Isn't this just slapping himself in the face?
There were many people who had the same idea as Raphael. Some even thought that Lin En was crazy or was deliberately saying some weird things to attract their attention.
Amidst the doubts, Lin En spoke again. "In my opinion, the so-called gravity is essentially a phenomenon of space-time curvature!"
The current mainstream theory in the Wizarding Land is that gravity affects and distorts space, but Lin En reversed the cause and effect. It is because of the changes in space that the gravitational phenomenon occurs!
So someone immediately stood up and asked, "If it's not gravity, then what kind of force caused the space to deform?"
"Of course it's mass!" Lin En said firmly. "The reason why we feel the influence of gravity or gravitational force is because the huge mass of the planet under our feet distorts time and space, forcing us to fall towards the center of the earth..."
Harrov and a few great wizards who specialized in force field magic had thoughtful expressions on their faces.
And those official wizards felt that their brain power was no longer enough. Every word Lin En said was constantly challenging the limits of their imagination and thinking ability!
Gravity does not actually exist, or it is just a phenomenon. In fact, it is the space that is pulling them in a certain direction.
This invisible and intangible change in space is difficult for many wizards to understand, especially they cannot imagine how the distortion of space can achieve this.
Lin En did not give a long explanation, but moved sideways. On the platform behind him was a round piece of cloth made of feathered serpent skin and had very good elasticity.
It was placed on an iron frame and was tightened tightly.
Everyone present looked over curiously, and Lin En picked up a ten-kilogram ball and placed it in the center of the round cloth.
The next moment, the originally flat round cloth suddenly sank, forming a curved surface with the sphere as the center. The degree of curvature became weaker as it went outward.
"As for the so-called gravity, it's like this!"
Lynn took out a one-kilogram ball from his pocket, casually pressed it on a corner of the curved surface, and then let go.
Everyone in the seminar stared with their eyes wide open. The wizards in the back row stood up, and some even used farsighted magic to see more clearly.
Without Lynn applying any additional force, the ball automatically rolled towards the center along the curvature of the surface.
"So that's it, gravity... this is gravity!" A great wizard was so excited that he could hardly contain himself. He imagined a three-dimensional cloth, and then all directions collapsed towards the center, attracting objects.
Without waiting for everyone to recover, Lin En picked up another small ball, changed the angle and applied a little force, giving it an initial speed. The small ball then changed its way of movement and no longer rolled straight down, but followed the curved surface, continuously rotating around the large sphere in the center.
"Star orbit, this is the star orbit!" another person shouted excitedly.
The eyes of all wizards were focused on the white round cloth with a diameter of only one meter. They vaguely felt that they were not staring at a few spheres, but the great picture of the stars in the universe!
Lynn very intuitively used a piece of elastic leather to display the distortion and collapse of three-dimensional space in the form of a two-dimensional surface!
However, the distortion of time cannot be presented in such an intuitive way.
Fortunately, this is enough. This little experiment is just to help these wizards better understand the phenomenon that space curvature produces attraction.
Lynn looked at the wizards in the seminar who were either excited, absent-minded, excited, or fanatical, and summarized again.
"So I think gravity is a geometric effect caused by the curvature of space-time. Matter tells space-time how to bend, and space-time tells matter how to move!"
Matter tells space-time how to bend, and space-time tells matter how to move... The wizards in the hall who have some understanding of force field magic are constantly chewing on these words.
Exquisite, so exquisite!
This is the secret of the magic of time and space!
"Mr. Lin, your speech today alone is enough to earn you a nomination for the Corona Medal!" A great wizard in charge of maintaining order in the venue sighed as he looked at Lin's slightly childish face.
At the last seminar, the legendary wizard Harof threatened to award Lin En with the Corona Medal. He was a little indignant. The other party did propose a set of star pictures that went against mainstream theories, but it was not to the extent of issuing a Corona Medal. A Silver Moon Medal would be enough!
But now it seems that although Lin En is just a formal wizard, his understanding of gravity and space is far beyond his reach.
Every word spoken today can serve as the founding theory of space magic. Some fanatics even recorded Lin's description of matter and time and space verbatim. Even if they didn't understand it, they could always use it when talking and bragging to others in the future.
"I have another question... Why doesn't the planet under our feet rush towards the sun under the influence of gravity? Just like that little ball." Raphael asked in confusion.
The second small ball that Lin En dropped continued to rotate around the curved surface as it fell, but the amplitude was getting smaller and smaller, and it would eventually be sucked into the side of the big sphere.
"That's because there is no air resistance in a vacuum. The speed of the stars will not slow down, forming a balance with gravity, and of course they will not fall into the sun." Lin En explained.
Raphael thought about it and noticed that the small ball was moving closer to the center because its speed was gradually slowing down. Its track became shorter and shorter, and finally it fell into the center of the curved surface.
It turns out to be like this!
Raphael suddenly understood, and many of his previous doubts about the orbits of stars were instantly resolved.
Chapter 159: Calculating the gravitational constant by mirror reflection
After Raphael sat down contentedly, another great wizard who was proficient in force field magic asked curiously.
"Mr. Lin, since you said that it is mass that causes the distortion of space and thus the phenomenon of gravity, does that mean that only massive stars have this characteristic?"
"I think Lord Harof's theory of gravity has explained this very clearly. This phenomenon exists widely in all things." Lin En replied calmly.
"What about a grain of sand or a stone?" Lydia raised her hand high and asked a question that puzzled most people present.
"Of course!" Lin En nodded and explained. "It's like putting an object into water. Even if it's a grain of sand, it will inevitably displace the water!"
"Then why have we never felt the attraction brought by this so-called... space distortion?" Luo Er couldn't help but stand up. This was also the question that confused him the most.
If gravity exists in any object, then it should exist in them as well. That's why when they walk on the road, the sand and stones on the ground are not sucked over.
"That's because compared to our mass, its impact on space and time is too small. Even in front of a towering mountain, its disturbance to space and time can be almost ignored. Its attraction to you is probably far less than that of a gorgeous lady who happens to pass by!" Lynn said jokingly.
Among the four fundamental forces, although the range of gravity is theoretically infinite, it is the weakest force.
This wonderful analogy made Rolle laugh and cry, but he still asked another important question: "Since the influence of gravity is so weak, how can we be sure that it exists in everything?"
Only great wizards can barely feel the subtle changes in the curvature of space. For formal wizards, if they want to understand time and space, they can only rely entirely on imagination.
"Sir Rawl, in fact, this is exactly the topic we need to discuss today!" Lynn clapped his hands as he spoke. Johnny, Alok and others immediately stepped forward and pushed up a very sophisticated experimental device.
It looked like a beam balance for weighing heavy objects, but a two-meter-long steel wire was tied to the top, making it suspended in the air, with a small ball weighing one kilogram placed at each end of the swing arm.
Are they preparing for a weigh-in? The wizards at the meeting were confused, but they quickly rejected this guess because Lin En asked Johnny and others to move two 50-kilogram iron balls next to the small ball.
Lin En then explained. "As I said before, gravity exists in all objects. They always attract each other. Although it is very weak, it does exist. It just requires some special means to see this disturbance."
"I think you have not forgotten the previous pendulum experiment. It only takes a thin steel wire rope to amplify a slight disturbance. This torsion balance device also uses a similar method. I call it the micro-deformation amplification method!"