第５４７堀：世界の全貌をほんの僅か知る (Part1)
### Chapter 547: Knowing a Mere Fraction of the World's Full Picture
**Side: Yuki**
"Why would you say something like that..."
For some reason, Seraria was looking at me with a teary-eyed, sorrowful expression. Honestly, this is the first time I’ve seen Seraria, who is usually so strong-willed, look like this. I suppose this is the result of her trying to devise countermeasures ever since I was summoned, and while I can understand her feelings, that doesn't mean the impossible suddenly becomes possible.
"I know you’re saying this because you’re worried about me, Seraria, but even so, what’s impossible is impossible."
"It’s not impossible, is it? As I said before, if we use DP to procure the necessary materials and knowledge..."
"That’s exactly where the problem lies."
"What do you mean?"
"...That’s why it won't work. Your basic knowledge of Earth, Seraria, is roughly at the level of a Japanese middle or high schooler, and you only know the bare minimum about space, right?"
"...Well, I suppose so."
"Military airports are fine. Considering future national defense, I do want high-mobility units capable of immediate response. But space is a no-go. There are too many uncertain variables."
"Uncertain variables? Are you talking about stimulating dragons or unidentified monsters that might exist in the sky? Surely we could handle that with air power, couldn't we?"
"I’ve said it before, and I’ll say it again: that’s why it won't work."
"So, that’s not the only problem?"
Since it’s rare for me to shoot down Seraria’s ideas so repeatedly, she seems to have realized that there is something fundamentally wrong with the plan.
"Listen, Seraria. First of all, the problem is that space development, much like territory management or business, involves a vast array of tasks. You understand that having the knowledge alone isn't enough, right?"
"Yes. That’s why I said we should use DP to acquire that knowledge..."
"You guys complained of headaches just from learning Japanese. I have no idea what would happen if you tried to cram the mountain of space-related knowledge accumulated on Earth into your heads."
"..."
That is the first problem. You can't just say, "If you don't have bread, eat cake," or in this case, "If you don't have knowledge, just download it with DP." Knowledge of space is incredibly diverse and multifaceted. From the positioning of stars to mathematical verification, geological knowledge, and of course, aerodynamics and construction engineering—a vast amount of expertise is required.
Seraria keeps saying, "Just leave it to Zargis and Comet." To call this an unreasonable demand would be an understatement. Their specialties are magic and magical arts. While they certainly have vast knowledge and creative thinking compared to others, it’s fundamentally impossible. If they could do it, they would have already absorbed all of Earth's knowledge by now.
"You understand this, right?"
"...I do. Then, does that mean we need to gather more people?"
"It’s not just that. Gathering the right people is a struggle in itself, but the biggest problem is that this isn't Earth. In other words, there’s no guarantee that Earth-based knowledge will apply here."
"Eh? But didn't Taizo, Comet, and Zargis conclude that airplanes could fly? Right?"
When she turned to them, the two of them answered with wry smiles.
"Well, paper airplanes fly just fine here, so..."
Comet folded a piece of A4 paper from her desk into a paper airplane and threw it. It proved that the aerodynamics here are equivalent to Earth's, but...
"However, that only applies to the range we can call 'the sky'."
As Zargis said, that only goes as far as what we call the sky.
"What do you mean?"
"We don't assume that the atmosphere, the outer atmosphere, or space itself are the same as they are on Earth. If we’re unlucky, even if we launch an Earth-made spacecraft into the sky, there’s a possibility it won't reach space. Or rather, I consider that possibility to be quite high."
"Why do you think that? You said airplanes can fly, so why not spacecraft?"
"As you know, Seraria, the continent where the Findar Empire is currently visiting Weed has an eight-hour time difference from the Rogari Continent, right?"
"Yes. After the meeting over there, it became night, but when I came here, it was just past noon. That time difference makes things quite difficult, actually."
"Exactly. But, as you know from the satellite photos Luna showed us, doesn't it strike you as strange that there is almost no time difference with the If Continent, which is quite a distance away across the sea to the west of the Rogari Continent?"
"Oh? Now that you mention it, that is true. Why is that?"
I had been wondering about the lack of a time difference between the If and Rogari continents for a while, but with the time difference between the continents where Haiden and the Findar Empire exist, I’ve finally managed to form a vague hypothesis. No, I’m sure I could figure it out easily if I performed proper observations, but knowing that wouldn't change anything immediately, and I had other things to do.
"I haven't grasped it completely, but there is a time difference with the New Continent, while Rogari and If have almost none. The conclusion drawn from this is that the distance between Rogari and If falls within the range hit by sunlight at the same time. In other words, it leads to the conclusion that Aulorito is larger than Earth."
"???"
Seraria was experiencing a massive overflow of question marks. As I was wondering how to explain this, Comet stepped in to help.
"Err, let's see. Zargis, could you grab that globe? I'll bring out a baseball."
"Ah, I see. That’s a good idea."
They placed the globe and the baseball in front of Seraria.
"Right. Seraria, first of all, what Yuki-kun is trying to say is this: let's mark two points on both of these spheres—the globe and the baseball—at the same distance. Let's say... five centimeters should do. Think of these as the Rogari Continent and the If Continent."
Comet used a marker to put two black dots five centimeters apart on both the globe and the baseball. Zargis then shone a light from one side.
"Now, think of the side hit by this light as the part illuminated by the sun. If we rotate these at the same speed, what happens? Which one will have the black dots fall into shadow first?"
"That would obviously be the smaller baseball... Ah, I see what you mean!! Even if the distance is enough to cause a time difference on Earth, that same distance isn't enough to create a clear time difference on Aulorito. Wait, but if that's the case, doesn't that mean a day isn't 24 hours?"
"No, the previous condition was just to explain the time difference regarding which one enters the night first at the same speed. It’s almost certain that both Earth and Aulorito rotate once every 24 hours. It’s just that because the sizes are so different, Aulorito’s rotation speed is likely much faster. We know there’s only about a 15-minute difference in sunrise and sunset between Rogari and If. It’s not that there’s *no* time difference."
"I see, I see."
"Well, I don't know why the gravity is still 1G like Earth even though the planet is larger and rotates faster, but because of this, I don't have the naive assumption that the escape velocity or the second cosmic velocity would be the same as Earth's. After all, this world has this mysterious thing called magic."
"I don't really understand that 'velocity' thing, but I see. That’s why you think launching a spacecraft would end in failure."
That is the second reason. Because the environment is so different from Earth, I believe that even if we ordered Earth-made equipment, it would fail. As for gravity, one could hypothesize that the sun, which attracts this planet, might be mitigating the gravity of this massive Aulorito to keep it at 1G, but that’s not my field of expertise, and I don't know the details.
"And, the biggest reason of all..."
"What is it?"
"We don't have the budget. Space development costs an astronomical amount of money. Even if we used Weed's entire annual budget, it wouldn't be enough. It would take at least one trillion DP."
"Hah!?"
Seraria’s eyes widened in shock. I would do it if I could afford it easily, but space development is expensive. It seems that doesn't change even here.