Voyage of the Stars.

Chapter 714 Reversal of Centrifugal Force
In the history of human scientific development, there have been many studies on black holes, and there have naturally been many studies on the related black hole photon balls. After all, the reason why a black hole is called a black hole is that its gravitational force is so strong that it can even capture light, which is why it is difficult to observe in the starry sky.

The study of black holes is closely related to photons, or in other words, most of the physics research in the universe is related to light.

Black holes exhibit three physical properties: mass, charge, and angular momentum.

The black hole was formed by the merger of ancient stars, and it has swallowed up all the dust nearby, leaving no accretion disk. Such black holes grow larger as they swallow matter, and they also show a neutral charge because the matter is electrically neutral.

Therefore, if we study it through direct observation, we can only study it through two parameters: mass and angular momentum. However, its impact on other objects around it is also one of the ways to study it, such as its photon ball.

The photon ball of a black hole is those photons that are bound by the powerful gravitational force of the black hole and cannot escape temporarily. They are like a layer of light shell attached to the black hole, making the black hole look like a magical light ball whose back can be seen directly from the front at a close distance.

The thickness of this light shell has long been calculated by humans through the principles of general relativity, which is 0.5 times the radius of the black hole. The Schwarzschild radius of a black hole is the radius of the sphere formed by the black hole's event horizon. In other words, the so-called photon sphere thickness is the distance from the black hole's event horizon to 1.5 times the Schwarzschild radius of the black hole.

So, what does it mean that humans discovered through the tachyon detection that the black hole's dark radius suddenly expanded from the original radius to 1.5 times the radius? The distance from the outermost edge of the photon sphere to the black hole singularity is also 1.5 times the black hole radius. Is it a coincidence? Or is there another reason?

On this issue, scientists have made it clear to everyone that this is not a coincidence.

The explanation of this matter has to start with human beings' research on the black hole photon sphere. Scientists have calculated through a certain black hole solution in the general theory of relativity that the gravitational force received by photons on the photon sphere is exactly equal to the centrifugal force generated by them orbiting the black hole, and in opposite directions.

Well, there is nothing unusual about this, it is in line with normal human logical thinking.

The centrifugal force on photons outside the photon sphere is greater than the gravitational force on them from the black hole. The speed of photons is so fast that it has reached the speed of light, so the photons cannot be bound here. The faster the speed, the greater the centrifugal force. This is normal and logical.

But the solution inside the photon sphere is unexpected and does not conform to normal human logic, because the direction of the centrifugal force of the photons in the photon sphere is reversed, and the centrifugal force becomes negative, pointing to the black hole. In other words, the faster the photon is in the photon sphere, the greater the traction it receives from the black hole, which is very counterintuitive.

However, no matter how fast the speed of photons is, it is still the speed of light, because they are light, so the faster the speed of photons, the greater the negative centrifugal force they receive seems to be nonsense.

In fact, this is not the case, because in general relativity, this centrifugal force reversal to negative only applies to particles with zero mass, that is, photons. Once other particles with positive mass enter the photon ball, they will fall directly into the black hole and cannot run stably in the photon ball at all. This is why the photon ball is called the photon ball instead of the accretion disk.

So, since the faster the photons in the photon sphere are, the greater the negative centrifugal force they receive, while the centrifugal force received by the photons on the photon sphere is positive and equal to the gravitational force received by the black hole, does the speed of the photons in the photon sphere slow down or speed up relative to the photons on the photon sphere? Which of them is the speed of light?
In this case, should we change the definition of their speeds to faster light speed and slower light speed? If so, which one is the real speed of light? Can the speed of light be changed?
Or are their speeds still the same?

According to the calculation results that the centrifugal force on massless particles such as photons in the photon sphere is negative, and the faster the speed, the greater the negative centrifugal force, so they should have fallen into the black hole long ago. How can they still run stably in the photon sphere? After all, there is no positive centrifugal force. The negative centrifugal force and the gravity of the black hole on them both point to the black hole singularity. The forces all point in one direction, so they should not have the so-called stable running area, and the photon sphere does not exist.

But the facts of the universe tell us that photon balls do exist, that is, photons can still run counterintuitively and stably under negative centrifugal force. It is impossible that the universe is wrong, so it must be that human beings’ own theories are wrong? Or is it that human beings’ theories are also correct, but they just do not conform to human normal logical thinking?

If it is the latter, then the question is, how can photons run stably? Should the speed of photons be faster or slower as they get closer to the event horizon? The speed of light is the same, but there is a difference between fast and slow. Does the speed of light really change?

Obviously, as long as the calculation results are recognized, the speed of light will not change, because it is the result obtained from the general theory of relativity, and the premise for the validity of the theory of relativity is that the speed of light is constant.

The speed of light in a vacuum remains consistent for all observers, regardless of the observer's speed of movement. This is the famous principle of the constancy of the speed of light.

Therefore, the speed of light observed by humans should remain consistent. There is no such thing as a faster or slower speed of light.

So what physical phenomena happened in the photon sphere that caused such contradictions in the phenomena observed by humans? !

The answer given by human scientists is that the speed of light remains unchanged, only this space-time has changed.

As for why tachyon detection can get such a result, it is because tachyons are also subject to negative centrifugal force here, and because the faster the speed, the greater the negative centrifugal force, so superluminal tachyons cannot get out after entering this range. That's why humans see in the feedback that the radius of the 'dark' black hole representing the black hole becomes larger and is the same as the radius of the photon sphere.

This can explain the phenomenon of black hole enlargement observed in tachyon detection.

If this conclusion is correct, then human scientists can determine that certain physical properties of tachyons under certain special circumstances have the same properties as photons.

What a coincidence! This conclusion is completely consistent with the process by which humans obtained tachyons. After all, humans obtained tachyons from astronomical-level particle collision experiments, and particle collisions are the interaction of the four fundamental forces. Tachyons are the result of their interaction, and now they are somewhat related to photons, which is related to electromagnetic force.

Does that mean that humans can start from this direction to study tachyon technology in the future? This is obviously worth a try. I believe that the scientists who participated in this black hole exploration are already planning their own research direction after the exploration is completed.

Perhaps if we continue researching in this direction, we can find the type of tachyons predicted by tachyon theory that can be used in weapons.

As for the reason why the direction of the centrifugal force of photons is logically reversed within the boundary of the photon sphere, that is another branch of scientific research.

(End of this chapter)