"General Relativity ......"

His Excellency Braggs softly pronounced the name of the theory, feeling that there was some kind of appealing power in it.

"In addition to some of the conclusions of special relativity, general relativity also extends two principles."

Reiner added.

"The first is the principle of equivalence, that is, the kinetic effects of the inertial force field and the gravitational field are locally indistinguishable, because under the framework of general relativity, gravity is not a force in the traditional sense, but an interaction caused by the distortion of space-time caused by mass, and the equivalence principle is to drag gravity back to the original scope of discussion, and under certain conditions, gravity can still be discussed as a fundamental force."

The principle of equivalence is actually a bridge between classical magic and the system of magic under the framework of relativity, just as Albertonian mechanics is similar to quantum mechanics in the case of macroscopic low velocities, this principle codizes the law of gravitation proposed by Lord Alberton in the general case, and discusses the special case separately.

"The second is the principle of general relativity, that is, all laws of physics take the same form in any frame of reference, compared to the previous principle of narrow relativity, which extends from the frame of inertia to all frames of reference, which is also an indispensable cornerstone of the pursuit of truth by the masters."

After the redefinition of gravity, the principle of special relativity can naturally be extended to the principle of general relativity, which represents the meaning of the formula deduced by the mages, and the form of the determined theorem is unified in any frame of reference, in other words, there is truth in this world, and there will be no different theories because of different reference frames.

After talking about these two basic principles of general relativity, Reiner glanced at the Nethergate not far away.

"The phenomenon of gravity and space-time distortion reminds me of goldfish in a fish tank, if goldfish also have the wisdom of human beings, they will see distorted scenes when they observe the outside world through the spherical fish tank, but for goldfish who have grown up in a fish tank since childhood, this is normal."

He paused, then spoke.

"If a goldfish is lucky enough to leave the fish tank and not die, it will see the 'normal' world, which is contrary to its original cognition, but this is the real world, and the reason why its previous cognition is biased is because of the existence of the fish tank."

Reiner's words caused the mages to fall into deep thought, and it was obvious that the fish tank was now a gravitational field, a space-time distortion caused by a massive object.

In space-time distortion, the path of light changes, and the measured speed of light is also different, and the speed of light, within the framework of relativity, is a constant in this universe.

In other words, even the constants of the universe may not be fixed, and no one knows if there is a black hole in the galaxy where the planet is located, and the distortion of space-time caused by it changes the speed of light.

When people laugh at the goldfish in the fish tank, can they think that they may be in a bigger fish tank?

But general relativity tells the mages that the laws of physics are the same in any frame of reference, even if the constants are different, and at least the laws that the mages grasp are universal.

This makes a lot of sense.

This means that although the mages are physically confined to the fishbowl, their minds have touched the complex and chaotic world outside, which is the triumph of the mind.

The two legendary mages were a little emotional, they had been pursuing such a truth all their lives, but at this moment, it was proposed by a young mage, which made them feel relieved and a little regretful.

Reiner also had mixed feelings after summarizing the general theory of relativity.

It was only after he mastered the powerful magic and reached the pinnacle of this world that his personal strength reached the pinnacle of the world, and only after he actually observed the phenomenon of light bending and even came into contact with the netherworld gate like a black hole, did he deduce the general relativity of this world.

But in another world, a young man was able to sit at his desk and gain insight into the truth of the universe just by calculating with pen and paper.

What wisdom this is.

After a moment of contemplation, Reiner continued.

"According to the phenomena we have observed so far, the original theory of relativity did not take into account the problem of gravity and was flawed, so it was revised, and in the general theory of relativity, we can predict that when the mass of an object is concentrated at a certain point, the space-time distortion around it will become so strong that even light cannot escape, this point I call singularity, and this area, I call it a black hole."

Reiner's summary is based on reasonable inferences supported by general relativity, and is an extreme case and a prophecy.

"Black Hole ......"

Lord Alberton also thought of the Nether Gate not far from the Abyss Diver, but compared to the dark black hole from Reiner's mouth, even light could not escape, the distortion in front of him did not seem to have such a great gravitational pull.

"Wait, Reiner, if even light can't escape from a black hole, then we can't observe this object at all."

Field thought that people's observation of celestial objects is essentially the observation of the light emitted by them, even those stars that do not emit light can be found through spectral analysis, but black holes cannot escape by any light, and in the framework of relativity, that is, no information can be transmitted from black holes, and people have no way to explore this special celestial body.

"It is true that with conventional means, we have no way to observe black holes, but under the huge gravitational force, the surrounding celestial bodies will inevitably have different movements, just like potholed roads will inevitably affect the operation of horse-drawn carriages, and we can measure the existence and location of black holes through similar situations."

Reiner nodded, and continued.

"For example, since a massive object can generate a strong gravitational field that causes light to bend, we can see through this massive object other celestial bodies that are obscured by it."

He had a projection of light in his hand, which was a system composed of several celestial bodies, and he could see that although the light emitted from the distant stars would be obscured by the middle celestial bodies according to common sense, due to the strong gravitational field, the light was bent, and the light of the distant stars could be seen instead, so that this massive celestial body was like a lens, reflecting the things behind it.

"That's the gravitational lensing effect."

Reiner said that the moment he said the phenomenon, everyone present immediately thought of an object and had a similar feeling.

That's the Nethergate.