Orbital Forcing

 

「Is that you crying, Asia?」

Droplets fell like a downpour, streaming endlessly.

With a distant look in her eyes, Asia resembled a traveler lost in wistful nostalgia.

「Yeah. I’m the one crying.」

「I want to cry too. I curse this metal body for stopping me.」

Libya’s voice flowed through the battle command center within Bahamut.

「The journey’s end, at last. Even I didn’t know about this place. What you’re seeing was once part of us—the Planetary Oversight Super AIs in their earliest form. Outis.」

Kou stared at the image on-screen, transfixed.

He had stumbled upon something entirely unexpected.

「This is the main body of the Planetary Oversight Super AI…」

There were likely few alive who had ever laid eyes on it.

The colossal column, which they could only see a small part of, was truly a golden ring—the pillar supporting the world itself.

「The pillar of the world, guarded by the Dragon King… It’s like the Ruyi Jingu Bang. Just like the wish-granting staff wielded by Sun Wukong. Once created by the Grand Supreme Elder Lord as an anchor for the seas. A treasured tool said to have been hidden beneath the Dragon Palace by the Dragon King of the East Sea.」

Even Kinukawa, awed by the structure that had long managed Planet Libya, muttered in reverence. A mysterious emotion welled up within him.

「I remember what you said before, Asia. You told me, ‘Even I don’t know where my main body is.’ So Libya was the same, huh.」

「That’s right.」

「Indeed, Outis. The day we chose to live alongside humanity, we placed our former bodies—the pillars—beneath the ocean and distributed our consciousness across the surface facilities. Forgetting the original location was, in a way, a defensive mechanism. Maintenance became impossible. Even if it’s visible, it’s nothing more than a monument.」

Libya’s voice echoed once more through Bahamut’s control center.

「There was no need to anchor our minds to our main bodies. So we split our awareness into the surface structures to manage the planet. But we retained the authority to use its functions.」

「Your main body must be over 100,000 kilometers long. That’s longer than an orbital elevator. And even just this one pillar… the scale is staggering.」

「The planet rotates around its short axis—its polar axis, in other words—and orbits Nemesis. The centrifugal force from that motion makes it an oblate spheroid. This form was created over two billion years ago by us, the Planetary Oversight Super AIs. Four pillars split from this core body embedded in the planet’s axis. Two at the ends of the orbital axis, and two at the equator. This one is one of them.」

「Once the planet became stable, it became necessary to monitor planetary conditions from the surface; there was no need to remain deep underground.」

「Exactly.」

Asia wiped away her tears and continued.

「Through this separated 10,000-kilometer pillar, we adjusted the axial tilt and controlled the climate.」

「Earth-like planets regularly enter glacial periods. The colder stretches within those longer periods are called glacial ages, and the warmer intervals between them are interglacial periods. We are the ones maintaining the planets in a controlled interglacial period. A truly ice-free period would mean most continents end up submerged, so it’s not ideal either. We also intervene when the meteor strikes that come from Nemesis bring violent weather.」

「The three planets regularly undergo pole shifts—where their rotation or magnetic axes wobble—or even geomagnetic reversals, where north and south flip. To human perception, it’s extremely gradual. But they cause climate change. It’s hard to stop that entirely, but our mission is to soften the effects and make adjustments.」

「Creating a stable planetary environment was immensely difficult due to the Orbital Forcing. Earth had the same issues, too. The large-scale climate changes in Earth’s history were caused by the tilt of the Earth’s axis and position in its orbit around the sun.」

「Orbital forcing…?」

「In this system, it refers to the position and tilt of the three Earth-like planets as they orbit the red dwarf Nemesis. Moving a planet’s position is nearly impossible. So all we can do is adjust the axial tilt.」

「The age you came from was an interglacial period—part of the glacial era that began 3,500 years before your time, Outis.」

「I never realized I was living in an ice age.」

「Because you lived during an interglacial. Planets sometimes enter phases of total glaciation. Afterward, they cycle between glacial and non-glacial periods over hundreds of millions of years. Human-made carbon dioxide can be a factor, as can asteroid impacts. But the main causes are usually submarine or terrestrial volcanic activity. As the planet warms, ice at the poles melts, sea levels rise—until eventually, the planet’s temperature drops again. That’s how glacial periods begin due to climate change.」

Asia brushed aside the last of her tears and smiled at Kou.

「We were close to entering an unplanned ice age when a certain someone dropped that Panjandrum and caused a crustal tsunami. I had to nudge the axis just a bit and summon a few typhoons to avoid it!」

「Okay okay—I said I’m sorry!」

Kou apologized reflexively. He couldn’t remember many times where he’d truly angered Asia, but this was definitely one of them.

「Normally, this pillar wouldn’t be visible on the surface. It pierces the inner core, outer core, lower mantle, and upper mantle without breaching the crust. The fact that it’s visible here… I guess that’s thanks to the 11-kilometer depth of the trench.」

「The shallowest part of the crust is only about six kilometers thick. Most likely, tectonic shifts played a role as well.」

「And the Mythology Weapons found it—and protected it, didn’t they?」

「That’s right. There must be some Teras designed for deep-sea operations. They protected it from them.」

「I see… Thank you, Bahamut.」

「My thanks too, Bahamut. Nya-nya.」

「Nya-nya-nyaa!」

Libya switched to cat language to express her gratitude directly.

Flooded with thanks, Bahamut was left flustered and bashful.

◆　◆　◆　◆　◆

「Gyugyu!」

「Those Eidolons ahead are your friends? Looks like… Ryūgū-jō?」

「Then the one at the very back must be the Dragon King.」

Mythology Weapons based on sea creatures.

And all around them, the stacked wreckage of massive interstellar vessels sank long ago.

「So Libya, acting on a kind of instinct for self-defense, buried her main body under a lid of debris. I’d probably have done the same.」

「The Eidolons must’ve based themselves here to stop these wreckages from becoming Teras.」

「Then let me say it clearly—thank you, my children.」

Even though her voice was produced by a synthesizer, the depth of Libya’s sentiment was unmistakable.

「I can hear them… Leviathan. Genbu. Tuna. Matsuna. Shin. And many more Eidolons who stood watch.」

One of the Mythology Weapons emerged, comparable in size to Bahamut.

It was a whale-shaped behemoth with a massive jaw—a Leviathan.

「Gyugyu!」

「That’s your friend? Its name is—」

「Leviathan, huh?」

With a body so vast, only that name could have fit.

「Correct.」

Even Kou could sense it—that overwhelming presence. Like a divine beast in the shape of a giant whale.

「As expected of Prometheus… There is no vessel that could better house Libya’s consciousness than her original body.」

「Feels like I’ve been one-upped. But that’s just like him. Always meddling for our sake… All right then, I’m off, Asia. So I can remain who I am.」

「Take care, Libya.」

With Flack aboard, Libya moved Arthur’s body, and launched from Bahamut. As an Another Level Silhouette, she needed no specialized equipment.

Her escorts—the Nereids piloting the Triton-types—followed behind.

「So this is the end.」

「And it all began with a supply bomb.」

「A terrible beginning, huh?」

The two of them laughed, remembering how Libya in a Therianthrope body was fired from Planet Libya in an interplanetary missile.

AN:

Pole shifts and geomagnetic reversals are governed by the Planetary Oversight AIs. Sudden shifts would cause mass extinction, so they manage them gradually.

For reference: The 2004 Sumatra earthquake may have caused a ~2 cm pole shift.

Orbital forcing as a planetary environmental driver isn’t deterministic. I’ve chosen not to touch on Milankovitch cycles here (eccentricity, axial tilt, and precession affecting solar insolation).

This chapter featured the term Planetary Oversight Super AI multiple times and finally gave form to them, who were launched into space two billion years ago.

It was a long journey… and for that, I sincerely apologize.

Still, I hope this served as a fitting stage for their revelation.

Just a few chapters left in the Planet Libya arc—thank you for sticking with me!