Raphael and the others paused for a moment, and then they felt that all the light in the hall had disappeared, leaving only a little light coming through the skylight on the roof, shining on the platform.

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?"

"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 worldview! After a while, another wizard stood up and refuted. "Mr. Lin, 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! The scene of the seminar immediately exploded, and thousands of wizards stood up and looked at Lin En in disbelief - he actually denied the existence of gravity!

How dare he?!

(End of this chapter)