The materials he had been searching for were in the reference room after all.
The reason Jin and the others had overlooked them was simple: preconceived notions. The documents hadn't been in the form he expected.
"I'm glad I listened to you, Laojun. Thank you."
『No, My Lord.』
The target materials had been filed away in an unremarkable folder alongside several other documents. Jin had glanced at the first few pages earlier and immediately judged that it wasn't what he was looking for.
"I really fell for it..."
Jin reflected on his mistake.
"People see what they want to see."
These words are often attributed to Julius Caesar. They suggest that humans tend to interpret things in whatever way is most convenient for them. For example, it’s the groundless confidence of thinking, "It won't happen to me." Back in his days at the company, one of Jin's senior colleagues had no qualms about publicly declaring things like, "I've never had an accident, even when driving drunk."
But that was a digression.
The reason Jin recalled those words was because he had dismissed the folder after only a cursory glance, deciding it couldn't possibly be the right book. It was a classic example of wasting even more time by rushing a search—a mistake born of impatience.
"Let's see... 'This is a copy. Since the original is precious, it is to be kept under strict storage,' I see."
Even for the Predecessor, these records were precious. They had been written by Adriana Tierra—the beloved wife of her mentor, Shuuki Tsetse—and she had treated them with the respect they deserved.
"If I'd known that, maybe I should have searched the study first."
It was a case of being wise after the event.
"Well, what's done is done."
Jin shifted his mindset and began reading the materials.
"Alright, first is the composition of space."
According to the documents, free ether existed even in the vacuum of space. Furthermore, she theorized that a lower level—a "sub" free ether—must also exist. This aligned perfectly with Jin’s own hypotheses.
"She writes that it would likely be impossible to cross through space without mastering sub-ether..."
Adriana Tierra had noted that both were likely particles or waves that were not defined by traditional laws of physics. Reiko and Laojun listened in silence as Jin read the passages aloud.
"Next is the modeling of space."
The text proposed a model where the universe containing their world was a "microcosm," and clusters of these microcosms gathered to form a "macrocosm." This was remarkably similar to the cosmological models imagined by science fiction writers on modern Earth.
"She compares them to bubbles in water, or droplets of water floating in the air. I see."
"And here is the method."
The focus of the research was how to connect those bubbles or droplets.
"To do that, one must master sub-ether. Because sub-ether is not bound by the laws that govern space... She really was amazing."
Jin was full of praise. He considered Adriana Tierra an absolute genius for developing such deep insights into phenomena she couldn't even satisfactorily verify. Jin himself had previously organized his thoughts on the concept of "under ether"—particles he estimated to be the medium for mana waves—though they remained unconfirmed since he lacked the means to detect them.
"To cross space, one must change their perspective. I see, it's like how the whole landscape becomes visible when you look down from a higher position."
Because she used relatively simple analogies, even Jin, who wasn't a specialist in the field, could grasp the concepts.
"Ultimately, she writes that the first key is whether or not one can manipulate sub-ether."
The hypothesis stated that a staggering amount of energy would be required for such a feat. Adriana Tierra continued her explanation:
Even if one could generate sub-ether waves, there were further technical hurdles to overcome. Due to its nature, sub-ether had high linearity and was thought to penetrate almost any substance. She theorized that a material capable of refracting sub-ether waves would likely need a density of around several hundred thousand to several million times that of ordinary matter.
As a side note, the companion star of Sirius (Sirius B) is made of such ultra-high-density matter; despite being roughly the size of Earth, it has a mass comparable to the Sun. Such stars are called white dwarfs, and their density is roughly one million times that of water—about $1 \times 10^9$ kilograms per cubic meter.
"Could I manage that if I used a barrier to compress it?"
Jin thought of how adamantite was created by compressing matter within a barrier. He wondered if he could push that process even further, though he didn't yet know if that level of extreme compression was possible.
Adriana Tierra concluded that by using those sub-ether waves as a carrier wave, it might be possible to traverse space. The use of the term "carrier wave" was almost certainly an influence from Shuuki Tsetse. Since AM radio worked by using radio waves in the kilohertz range as a carrier to transmit audio, it was likely she had heard the concept from him.
"Now, for the final summary."
According to the notes, manipulating sub-ether would likely be impossible for a human; it would require a magi-brain with processing power dozens or hundreds of times greater than a person's. Furthermore, generating sub-ether would require immense energy, and there were still many technical problems to solve before it could be handled.
Looking at the list of requirements, Jin didn't feel like this was something he could act on immediately.
"Father, was the search in vain?"
Noticing Jin’s troubled expression, Reiko spoke up with concern.
"...No, I don't think it was completely useless. I was just wondering if I could generate sub-ether waves."
He wondered if he could use them to "push back" against spatial anomalies, but then he grumbled to himself that he didn't even know if the law of action and reaction applied to such things.
"More than anything, my goal is to see if I can plug these 'holes' or prevent them from opening in the first place."
Laojun reacted to that statement.
『My Lord, as a possibility, could we collide an anti-phase wave against the space vibrations?』
"Exactly, Laojun. Not only that, I was wondering if we could 'strengthen' space itself."
『Strengthen it?』
"Right. If sub-ether penetrates almost all substances, unlike free ether, then even if we used it to set up a barrier, it shouldn't interfere with anyone's daily life, right?"
Laojun immediately grasped the logic.
『I understand. It is as you say.』
"The only problem is that I don't know the method for generating it or how to handle it yet..."
Jin suspected that even No. 700672 might not have the answers. Still, to avoid being blinded by his own preconceptions, he intended to consult No. 700672, the Supervising Brain Testa on Onogoro Island, and Jack on Uni after this.
It was at that moment that Laojun's voice sharpened.
『My Lord, an eighth space vibration has been detected.』
"What!?"
One before dawn, and now another in the afternoon. Two in a single day—what did that signify?
"Where is it?"
『Yes. It is in almost the same location as the last one, near the old relay base.』
"Alright."
That was the area where they had recently scattered the markers that transmitted ether waves.
"And the reaction from the markers?"
『Yes, regarding that...』
Jin focused all his attention on Laojun's explanation.