40. Cosmic Battleship Agirakana 1

As usual, I lounged in my usual seat in the Embassy’s Office, sipping coffee and watching everyone in the Secretary’s Office busily working at the operations desk. The usual corporate magnate vibe. It was true, I felt a weight had lifted—after all, we’d finally found Zeno’s countermeasure, the so-called “fatal blow.”

On Agirakana, under the new charter, exploration division-led initiatives had gradually begun to address long-neglected experimental facilities and research installations, now freed from the restrictions of the Arsen Charter.

“Captain, a communication has come in from Major Dora of the Exploration Division.”

“Patch her through.”

Major Dora’s face appeared on the monitor atop the desk.

“Commander. Good morning.”

“Good morning. Major Dora, is there something?”

"Your Excellency, I’m pleased to report immediate good news. The jump drive proof-of-concept test has succeeded. Using the Agirakana’s experimental jump drive—still in development—has reactivated a system long thought lost since the drive’s destruction, along with much of the associated technology. Just moments ago, the test prototype confirmed its functionality.

Currently, jump drive capability is limited to low-mass non-hull vessels, but the technical hurdles for hull-ship compatibility have been largely resolved. It’s now only a matter of time. For smaller probe units, we can already dispatch them to any designated coordinates at any time.

Still, the jump in this demonstration experiment is something of a degraded version of the jump drive researched at Arsen. Ideally, the time elapsed in real space from jump-in to jump-out would be nearly zero—but in this test, a delay of 0.1 percent has occurred.”

“A delay?”

“For example, if we jump 1,000 light-years, the spacecraft should instantly reappear 1,000 light-years away, right before your eyes. With our jump drive, however, the ship only appears at its destination one year later.”

“One year for a thousand light-years? Still, that’s not an issue for unmanned craft, is it?”

“This demonstration experiment was designed with the assumption that biological life could survive during the jump. If we disregard that constraint, we can shorten the time delay to one-quarter of the current duration.”

“Surprising, since it’s not what I expected from a jump drive—but if we consider that an unmanned probe equipped with that drive essentially travels at four hundred times the speed of light, that’s the takeaway.”

“Precisely. There are currently about one hundred twenty celestial bodies under consideration as potential sources of Zeno. By dispatching these jump-equipped probes to examine each one systematically, we can identify the specific body from which Zeno originated. If we can destroy that source, then—regardless of how many Zeno instances currently exist—they will all eventually reach the end of their lifespans, one by one, and vanish.”

“When do you expect the jump-drive-equipped probes to be ready?”

“We already have chassis for sixty probes, so within ten days—counting manufacture, installation, and calibration—we can equip the first probe with a jump drive. After that, we’ll proceed with the rest, sequentially.”

“Assuming we’ve identified the celestial body where Zeno originated—it’s either a neutron star or something closely resembling one, correct? Can we actually destroy something like that?”

“Currently, we’re still exploring methods to destroy neutron stars. There must be a way; we’ll find it, eventually.”

“That’s right—during yesterday’s meeting, several proposals were discussed involving multiple gravity thrusters to create a gravity well. Couldn’t we apply this principle to compress a neutron star until it collapses into a black hole? Neutron stars are essentially stars that failed to become black holes in the first place.”

“You’re quite right—there’s certainly room for possibility. If we create a new gravitational well at the core of a neutron star and steadily increase the gravity until collapse, the neutron star would begin to disintegrate from within, forming a black hole, and the surrounding matter would simply be swallowed whole.

However, a spacecraft equipped with a black hole–specific gravitational thruster would need to maintain a safe distance from the neutron star, meaning the gravitational well would have to be generated at quite a distance. The depth of that well would need to be considerable, so we’d likely require a large, high-output gravitational thruster.

Moreover, to counteract the gravitational pull of the well we’re creating, we’d need to generate an equal and opposite gravitational well elsewhere—using another gravitational thruster. So we’d need to pack all these systems into a single vessel, plus design a spacecraft capable of approaching the neutron star without collapsing under its own gravity.”

“Sounds like quite a large-scale operation, doesn’t it?”

"There are parts dependent on the neutron star’s mass, so it’s hard to say for sure, but even in the worst case, we could just install a jump drive and a neutron star collapse device together in Agirakana. I’ll leave the next report to you. That concludes this update. Excuse me."

"Major Dora, thank you for your efforts."

"Senior, what exactly is a jump drive?"

It seemed that Ichijō had quietly taken a seat beside me during our screen-to-screen conversation with Major Dora.

"Ichijō. When did you get there? I didn’t notice."

"Since just now. Am I intruding?"

"No, not at all. Hmm, let’s see—before we get to the jump drive, perhaps I should explain the hyperlane gate first."

A standard Agirakana spacecraft can reach about thirty percent the speed of light, but even at that pace, a one-way trip from Earth to Agirakana takes nearly seven years. That would be quite the inconvenience. Fortunately, we’ve installed a special facility—what we call a hyperlane gate—near Jupiter. Passing through it lets you arrive instantly at the corresponding hyperlane gate near Agirakana. With that, Earth and Agirakana can be reached in a single day, if you’re willing to push it.

And that’s what the jump drive is—something that lets you leap to any location, without needing to rely on hyperlane gates at all.”

“Sounds impressive. That’s about all I understand. I don’t know what it actually does, but I’m guessing it’s something good. That’s nice.”

“Thank you.”

"Is the hyperlane gate near Jupiter big, then? I haven’t heard anything about such a thing from ASUCA."

"Even though you claimed you didn’t understand a thing, you sure remember it well."

"The gate near Jupiter is a disc about three kilometers in diameter. Compared to Jupiter, it’s smaller than a mustard seed—no wonder you wouldn’t notice it. Anyway, your seventh floor seems to have gotten a lot more people lately. About eighty now, right?"

"Exactly eighty-five."

"Try to keep an eye on them, then."

With that, he dismissed the conversation with Ichijō, issuing a dry command to look after his subordinate—then abruptly cutting off any further entanglement.

In the research division that had finally secured a method to pinpoint the neutron star origin of Zeno, as soon as the jump-drive-equipped probe was completed, they dispatched it toward any celestial body suspected of being a Zeno source.

Four months had passed since Major Dora’s report.

“Captain, there’s a transmission from Major Dora of the Survey Division.”

“Patch her through.”

The monitor above the desk flickered to life, showing Major Dora.

“Commander. Good morning.”

“Good morning. Major Dora, is there something new?” The same exchange as before.

“We’ve identified Zeno’s primary star. It’s a neutron star designated 4U 0142+61, located twelve thousand light-years from the Sol system. The probe we sent has transmitted footage of Zeno emerging from the neutron star.”

The monitor above the desk switched from Major Dora’s image to a live feed of the neutron star itself.

At the center of the transmitted image, a pale blue star blazed with a painfully intense light. That was likely the neutron star. Plasma gas swirling around it was drawn inward, gradually condensing into a distinct form—Zeno. The newly born Zeno emitted what appeared to be neutron radiation in the form of white light, slowly drifting away from the neutron star and merging into the group of Zenos awaiting ahead.

Such Zenos were emerging at a rate of one every few seconds, glowing pale blue under the light of the neutron star. Even at a conservative estimate of one every five seconds, that amounted to over six million annually. The previous count—after two and a half years of preparation—had been three million fallen Zenos. Let it continue, and it would be catastrophic. No matter how limited Zeno’s lifespan might be, this rate of emergence was unsustainable. Moreover, within the stellar system, not only was the earlier group of Zenos visible, but multiple other groups could be seen as well.

The footage cut out after about three minutes.

"The probe that sent this transmission appears to have been destroyed by a Zeno. We're currently dispatching multiple probes toward 4U 0142+61."

"What about the method for destroying the neutron star?"

"After reviewing Your Excellency's proposal, we've determined there are no technical obstacles. It is entirely feasible to collapse the neutron star into a black hole. Calculations based on the target 4U 0142+61 indicate that, with current technology, we would need twenty-four gravity thrusters—each roughly one kilometer in diameter—combined with counter-thrusters, all operating in concert. Considering the need to carry auxiliary systems, and the necessity of approaching the neutron star while eliminating surrounding Zeno, no vessel other than the Agirakana would be capable of carrying such a setup."

"So the Agirakana will have to implement its jump drive and travel to 4U 0142+61, then."

"That is correct. Once we jump into hyperspace, twelve years will pass in both our internal space and real space before we jump out, twelve thousand light-years away. Inside hyperspace, there is absolutely no way to receive external information—so from our perspective, hyperspace could just as well be considered a void, a world of nothingness."

Twenty-four years round trip. Farewell, Earth. So that’s how it works.

[Supplementary Explanation]

Jump Drive

Transition into hyperspace, free from the gravitational bottleneck, move at superluminal speeds toward the destination, then re-enter normal space. Subjective time elapsed within hyperspace corresponds to actual time passing in normal space. Theoretically, subjective time during hyperspace transit should be zero—but errors arise proportionally to travel distance. In this experiment, the error was 0.1 percent. This equates to traveling at a thousandfold light speed without time dilation. For unmanned vessels, where biological activity can be disregarded, the effective speed is equivalent to forty thousand times light speed.