Chapter 132: Exploring Hell

It is unclear when it began, but the majority of Hua Feng, Yun Meng, and Bai Feng’s days shifted toward listening to the professors’ nearly endless conversations and the students’ inquiries. They were often lost in the discussions concerning wormholes, time travel, and interstellar exploration. Despite the confusion, they had to patiently endure lecture after lecture. Fortunately, their cultivation progress did not lag behind; through exploration of the techniques within the Flame Emperor’s Canon, Hua Feng was able to resolve many previously perplexing issues on his own.

His strength had also made significant strides. Outside of theoretical studies, they spent most of their time engaged in practical combat training. Through mutual encouragement, Hua Feng and Yun Meng reached the peak of the early-stage Level 65 Origin Emperor realm almost consecutively. Bai Feng also successfully broke through the Origin Sovereign realm to reach Level 62 of the Origin Emperor realm. The vampire bloodline, which she had once found extremely difficult to suppress, had become much easier to manage, and her cravings for blood had diminished significantly.

Witnessing Yun Meng’s rapid progress, Hua Feng could not help but marvel at the miraculous nature of the Snow Lord’s ancestral techniques. In this era, however, the strength of one’s cultivation level was not the sole metric; success relied more on how flexibly a practitioner utilized their internal origin energy or power. Only by pushing every ounce of strength to its limit could one achieve their goals, whether for victory or other aspirations.

For days, a knot had remained in Hua Feng’s heart. Beyond the uniquely gifted teachers, the true identity of Professor Sun—the one who had first lectured them on Journey to the West culture—remained something he was desperate to uncover. Although he had advanced two levels, he still could not gauge the depth of the professor’s power whenever they crossed paths on campus. Fortunately, he could sense that Professor Sun harbored no malice toward him or his students. The professor’s occasional words of guidance were like keys to new worlds, elevating everyone’s cultivation and state of mind. Yet, these gestures could not extinguish the suspicion and curiosity Hua Feng felt toward him.

On the podium, the professor’s voice continued, seemingly tireless and endless.

"So, what kind of wormhole can be considered a traversable wormhole? A primary condition is that it must exist for a sufficient duration; it cannot vanish before the interstellar traveler has a chance to pass through. Therefore, a traversable wormhole must first be sufficiently stable. How can a wormhole exist stably? Thorne and Morris discovered a rather discouraging result through their research: there must be some sort of exotic matter with negative energy within the wormhole! Why such a conclusion? It is because matter converges inward when entering a wormhole and scatters outward when exiting. This transition from convergence to scattering implies the existence of a repulsive force deep within the wormhole. Since the gravity of ordinary matter can only produce convergence, only negative energy matter can generate this repulsion. Thus, to make a wormhole a channel for interstellar travel, negative energy matter is essential. This finding by Thorne and Morris was the starting point for human research into traversable wormholes."

Why was the result of Thorne and Morris’s research discouraging? Because humanity had never observed any negative energy matter in the macroscopic world. In physics, the energy of a vacuum is typically defined as zero. A vacuum is supposed to be "nothing," and negative energy implies something "less" than the nothingness of a vacuum, which in classical physics is a near-contradiction.

However, many things impossible under classical physics became possible with the development of quantum theory in the early twentieth century. The existence of negative energy is, fortunately, one such example. In quantum theory, a vacuum is no longer empty; it possesses an extremely complex structure where vast numbers of virtual particle pairs are created and annihilated every moment.

In 1948, Dutch physicist Hendrik Casimir studied these virtual particle states between two parallel conducting plates in a vacuum and discovered that they possessed less energy than an ordinary vacuum, indicating the appearance of negative energy density between the plates! Based on this, he found that a weak interaction existed between such a pair of parallel plates. His discovery became known as the Casimir effect.

Nearly half a century later, in 1997, physicists experimentally confirmed this weak interaction, thereby indirectly providing evidence for the existence of negative energy. Beyond the Casimir effect, since the 1970s and 1980s, physicists have successively discovered the existence of negative energy in other research fields.

Therefore, various exciting studies indicate that negative energy matter does indeed seem to exist in the universe. Unfortunately, all such negative energy matter known to date is produced by quantum effects and is thus extremely minute in quantity. Taking the Casimir effect as an example, if the distance between parallel plates were one meter, the density of the negative energy produced would be equivalent to having only one (negative-mass) elementary particle in every quintillion cubic meters of volume! Furthermore, the larger the gap, the lower the negative energy density.

The negative energy density produced by other quantum effects is roughly similar. Thus, on any macroscopic scale, negative energy generated by quantum effects is negligible. On the other hand, physicists have estimated the quantity of negative energy matter required to maintain a traversable wormhole, and the results show that the larger the wormhole's radius, the more negative energy matter is needed. Specifically, to maintain a wormhole with a radius of one kilometer, the amount of negative energy matter required would be equivalent to the mass of the entire solar system.

If the existence of negative energy matter brought a glimmer of hope to using wormholes for interstellar travel, these more specific research results poured a bucket of cold water on that hope. On one hand, all known effects that produce negative energy matter are quantum effects, resulting in quantities that are minuscule even by microscopic standards. On the other hand, the amount of negative energy needed to maintain a macroscopic wormhole is an astronomical figure! This vast chasm undoubtedly casts a heavy shadow over the prospects of building a wormhole.

Although the numbers look discouraging, don't forget that when we discuss wormholes, we are discussing a science fiction topic. Since we are discussing sci-fi, let us remain optimistic. Even if we lack the capability to build a wormhole ourselves, perhaps other civilizations in the universe possess the ability, much like the stories in *Stargate*. Even if no one can build one, perhaps natural wormholes exist in some corner of the vast universe. So, let us assume that one day in the future, humanity truly builds or discovers a wormhole with a radius of one kilometer.

Could we then use it for interstellar travel? At first glance, a one-kilometer radius seems sufficient for the requirements of interstellar travel, as such a radius is geometrically large enough for a sizable interstellar spacecraft to pass through. Those who have watched sci-fi movies might have a deep impression of the special effects used to depict spacecraft crossing wormholes. On the screen, the ship is surrounded by an infinitely brilliant visual illusion composed of starlight and radiation from distant skies; it appears as if the ship is traversing a narrow tunnel in spacetime.

But the reality is far more complex than this fantasy. In fact, for a ship and its crew to safely traverse a wormhole, the geometric radius is not the main problem faced by interstellar travelers. According to general relativity, matter passing through regions with highly curved spatial structures, such as a wormhole, encounters a very thorny issue: tension. This is caused by the non-uniform distribution of the gravitational field in space; a familiar manifestation of this is the tides in the ocean. Due to the action of this tension, as an interstellar spacecraft approaches a wormhole, the crew would gradually feel their bodies being stretched along the direction of the wormhole and compressed in the perpendicular direction. This sensation is caused by the non-uniformity of the wormhole's gravitational field. At first, this tension might only cause slight discomfort, but as the ship nears the wormhole, the tension would increase rapidly; for every tenth of the distance reduced, the tension would increase by about a thousand times. When the ship is still a thousand kilometers away from the wormhole, this tension would already exceed the limits of the human body. If the ship did not turn back by this point, all crew members would perish under the lethal tension.

Flying a bit further, the ship itself would disintegrate under the terrifying tension, and ultimately, the crazily increasing tension would tear the debris of the ship and its crew into a long string of subatomic particles. What would emerge from the other end of the wormhole would be this long string of subatomic particles, their origins forever indistinguishable!

This is the fate that interstellar explorers would face if they attempted to cross a wormhole with a radius of one kilometer. A one-kilometer-radius wormhole is not a traveler’s paradise, but an explorer’s hell.

Therefore, for a wormhole to become a traversable one, a further, obvious requirement is that the tension experienced by the ship and crew during transit must be very small. Calculations show that this requirement can only be met if the wormhole’s radius is extremely large. So, just how large must a wormhole be to serve as a channel for interstellar travel?

Calculations indicate that the tension generated by a wormhole with a radius of less than one light-year would be sufficient to destroy the atomic structure of matter. This is something no sturdy spacecraft could withstand, let alone the fragile crew.

Thus, for a wormhole to be traversable, its radius must be far greater than one light-year.