This, then, was Xiao Yu's plan.
But the plan had a fatal flaw: fuel consumption before reaching Titan.
With Earth's current level of technology, spacecraft relied on rockets for propulsion. Once second cosmic velocity was reached and Earth's gravitational well escaped, a ship would largely coast on inertia. The fuel it carried was used mainly for minor orbital adjustments and necessary acceleration or deceleration. Xiao Yu's ship, however, was an exception.
His vessel had been assembled in geosynchronous orbit, then used its own onboard fuel to break free of Earth's gravity and head into deep space. Even though he had stockpiled as much fuel as possible and optimized efficiency to the extreme, merely escaping Earth's gravitational field had already consumed thirty-five percent of the total supply. After several further acceleration maneuvers, the fuel remaining on board was now no more than sixty percent of its peak amount.
Maintaining a long-term position hidden behind Mars would itself require a substantial expenditure of fuel. And there was more: deceleration upon reaching Mars' orbit, acceleration when leaving its gravitational field, and yet another deceleration when arriving at Titan—all of it added up to an alarming drain.
Originally, Xiao Yu had planned to fly directly to Europa. Among all the bodies in the Solar System, Europa—aside from Earth—was considered the most likely to harbor liquid water. With liquid water, and by exploiting the local environment with certain specialized techniques, Xiao Yu could collect liquid hydrogen and liquid oxygen as fuel. He would then devote himself to researching nuclear fusion technology. Once he had fully mastered fusion propulsion, he could gather sufficient fusion fuel from Jupiter itself, leave the Solar System, and head into interstellar space.
That neat, elegant plan had been utterly ruined by one event: the Moon's collision with Jupiter.
Left with no choice, Xiao Yu adjusted the direction of his engine exhaust, altered his trajectory, and set course for Mars.
Ten days passed.
During that time, the Moon had already crossed Mars' orbit, charging toward Jupiter like a maddened behemoth. Xiao Yu kept his cameras locked tightly onto it.
Another twenty days slipped by in the blink of an eye. Right on schedule, the fiery red disk of Mars appeared in his field of view.
After decelerating, the spacecraft's speed dropped to four thousand meters per second. This single maneuver consumed at least another five percent of the remaining fuel, making Xiao Yu wince in pain.
Yet the expenditure was unavoidable. Without slowing down, the ship would merely skim past Mars. Only at roughly four thousand meters per second could it be captured by Mars' gravity and enter orbit.
At an altitude of three thousand kilometers above the Martian surface, the ship successfully achieved a stable orbit. Xiao Yu drifted leisurely around the planet, quietly waiting for the moment of the apocalyptic collision.
This altitude was the optimal one, calculated with meticulous precision. From here, the ship could be completely hidden behind Mars, shielded from the energy unleashed by the impact, while also minimizing fuel consumption when it came time to escape Mars' gravity.
The spacecraft now traced a near-circular path centered on Mars. At Xiao Yu's current speed, one full orbit took less than two hours.
Before the Moon struck Jupiter, meteorites from Earth had already begun raining down on Mars. Recently, both the frequency and mass of impacts on the red planet had increased dramatically. Watching the flashes of light erupt across the Martian surface, Xiao Yu felt an inexplicable unease creeping into his heart.
The meteorites originating from Earth clearly bore signs of past life. Take one fragment, for example—three hundred meters long and fifty meters wide, with an albedo as high as 0.7. Its surface was unnaturally smooth and reflective. Xiao Yu inferred that it was most likely composed primarily of steel.
He coveted it intensely. In the future, modifying and upgrading his spacecraft would require enormous quantities of materials. But reality quickly crushed that desire. Let alone a meteorite of such colossal size—even a pebble was beyond his ability to collect. At these velocities, a pebble-sized meteor was equivalent to a hand grenade. Xiao Yu could no longer afford such accidents.
This was the largest meteorite he had seen so far. Back on Earth, the Tunguska explosion was believed to have been caused by a meteor roughly thirty meters in diameter that disintegrated in the atmosphere, releasing energy equivalent to over a thousand Hiroshima atomic bombs. This steel meteorite dwarfed it—dozens of times greater in both mass and volume.
Fortunately, when the impact occurred, Xiao Yu's ship happened to be on the opposite side of Mars. Even so, through optical telescopes, he witnessed the immense effect it had on the planet.
The colossal shockwave increased Mars' orbital eccentricity by 0.2 percent. At the impact site and its antipode, a mountain ten thousand meters high rose abruptly from the surface. Countless volcanoes that had long been dormant roared back to life, spewing ash and smoke that nearly blanketed the entire planet. The permafrost at the poles melted, and rains unseen for tens of thousands of years fell upon Mars. Several massive earthquakes all but reshaped the planet's face.
Xiao Yu felt, on a deeper level, the truth of an old saying:
The Solar System is a delicately balanced whole—pull one thread, and everything moves.
Earth's destruction was not Earth's affair alone. Its explosion was destined to affect the entire Solar System, and the consequences were vast beyond neglect.
Watching it all unfold, a strange sadness welled up inside him, a sense of shared doom.
"If there were any life on Mars," he murmured, "it must all be gone now."
Aside from skillfully dodging a few fragments ejected from the Martian impact, the event caused him little direct harm. If anything, it forced him to revise his estimates upward—once again—of just how devastating the Moon's collision with Jupiter would be.
As he thought about it, a faint anticipation crept in.
"An impact on this scale," he mused, "might not be unique in the entire galaxy, but at least within this spiral arm, it's rare. To witness such an event… my life hasn't been lived in vain."
Another twenty days passed. Ten days remained until the estimated moment of impact.
Xiao Yu gradually reduced his speed. Correspondingly, to avoid being pulled down by Mars' gravity, he had to increase the thrust of his engines directed toward the planet. Finally, on the day before the collision, he fixed his ship firmly behind Mars.
At this point, Xiao Yu, Mars' center of mass, and Jupiter's center of mass lay roughly along a straight line—maximizing his protection from Jupiter's influence.
Driven by sheer curiosity, Xiao Yu could not bear to miss witnessing such a once-in-an-epoch collision. He therefore deployed a small satellite in advance, placing it in Martian orbit. That way, even while hiding behind Mars, he could still receive relayed images of the impact.
At their current positions, Mars lay a full five hundred million kilometers from Jupiter. This meant that the images and effects of the collision would not reach him until roughly half an hour after it occurred.
Based on the data from his final observation, Xiao Yu began silently counting down.
In truth, the collision had likely already happened. The images simply had not yet traversed the vast distance of five hundred million kilometers. Imagining the earth-shattering scene, Xiao Yu's heart brimmed with anticipation.
"Ten… nine… eight… two… one!"
Everything unfolded exactly as expected.
Xiao Yu witnessed a sight beyond comprehension.
On the plane of the ecliptic, sunlight was almost entirely blocked by the debris produced by Earth's explosion. The Solar System lay shrouded in darkness.
Then, in that pitch-black void, a colossal light source suddenly ignited on the distant horizon—its intensity surpassing the Sun's by more than an order of magnitude. In an instant, it illuminated the entire Solar System.
The image lasted only a moment before the signal cut off. Xiao Yu knew why: the small satellite had been melted by Jupiter's overwhelming radiation.
Before he could recover from the shock, the effects of the Moon's collision with Jupiter reached him.
Blinding light, searing heat, and torrents of high-energy radiation swept over Mars, turning the planet upside down.
The earlier steel meteorite impact had already filled the Martian atmosphere with immeasurable dust, plunging the planet into darkness. Now, the energy from Jupiter struck. High-energy radiation superheated the already chaotic atmosphere, and the resulting pressure imbalance unleashed super-hurricanes. Winds so powerful they flung rocks nearly into Mars' synchronous orbit.
At the same time, the surface of Mars facing Jupiter began to melt. Rock and sand were heated into dark-red torrents, raging across the ground.
Faced with such overwhelming forces of nature, Xiao Yu did not dare to move. He hid silently behind Mars, watching it all unfold.
He felt profound gratitude for his decision. Without Mars as a massive shield, he would already have been reduced to a puddle of molten metal.
The high-energy radiation did not slow. After sweeping past Mars' orbit, it continued at the speed of light toward Earth's former orbit.
There, a vast swarm of comets had gathered. Under the Sun's radiation pressure, heat, and particle streams, each dragged a long tail behind it. Then Jupiter's energy arrived. Countless comet tails were blown apart in an instant. For a moment, it was as though the Sun had lifted its veil, blazing brighter—only for Jupiter's power to overwhelm it in the next instant, forcing the comet tails to stream toward the Sun instead.
By analyzing the light reflected from the comets, Xiao Yu estimated Jupiter's brightness at that moment.
At that instant, Jupiter's absolute magnitude exceeded the Sun's by more than an order of magnitude.
In other words, if Jupiter and the Sun were placed at the same distance, Jupiter would have shone more than ten times brighter than the Sun itself.
What awe-inspiring power.