bacchusnovels Chapter 294 The Boundary of the Solar System
Chapter 294 The Boundary of the Solar System
Pioneer flew for another two months after leaving the Kuiper Belt. On the instrument panel in front of Ji Beihang was a data point he had never seen in his forty years of flying: the solar wind particle flux had dropped to zero. Not close to zero. It was zero.
The particle environment outside the spacecraft is changing in a way that is invisible to the naked eye but perceptible to instruments. The solar wind speed continues to decrease, while the density of the interstellar medium increases. Pioneer has crossed the solar system's termination shock and entered the transition zone between the solar wind and the interstellar medium.
The heliopause. Humans call it the boundary of the solar system.
Shen Yiming instructed Ji Beihang to adjust the spacecraft's attitude so that the observation window faced the sun. He stood by the window for a long time. The logbook read: "Looking at the sun from here, it's no longer the star we see from Earth. It's just an ordinary star. It blends in with the other stars outside the window, indistinguishable without close inspection. The brightest object in our solar system becomes just a star thirty astronomical units away. This is the meaning of leaving. To let you know that what you thought was the center of the universe is nothing more than an ordinary light on the edge of the Milky Way."
Lu Yunfei monitored the status of the web-weaving link at the communications station. He discovered that from the moment it passed the termination shock wave, the synchronization pulses of the nine nodes of the web exhibited an unprecedented change. The pulses were not propagating between nodes, but oscillating in the vacuum surrounding the entire spacecraft. The frequency was exactly the same as the node pulses, but the amplitude continued to increase as the spacecraft approached the boundary.
He packaged the data and sent it back to Earth. He added a note: "The web seems to know we've reached the door."
All six crew members gathered in the observation cabin. Ji Beihang retrieved a flag from the storage compartment and unfurled it in front of the porthole. It had a dark blue background and two lines of text written on it, one in the founder's code and the other in Chinese: "We come from the Solar System. We are on our way."
It's not a national flag. It's the first interstellar civilization flag made by humankind.
Huo Zheng stood beside the flag for a long time, then said, "This flag was made from spare thermal insulation fabric from the Pioneer's maintenance bay. I cut it myself. I never imagined it would fly to the edge of the solar system. And I never imagined thermal insulation fabric would look more presentable on the interstellar boundary than in the engine room."
Wenya quietly observed everyone's expressions from the corner. She said, "I've performed two thousand surgeries on the ground and seen two thousand people wake up. But today, six people are standing in front of an invisible door, and no one needs to be woken up. Everyone is more awake than ever before. In all my years as a doctor, this is the first time I've felt that being awake itself is a miracle."
In his diary, Tan Yue wrote: "Today is a day without scientific data. No nodes to activate, no signals to decode. Today's only discovery is ourselves. Six people stand in an iron shell at the very edge of the known universe, watching the star from which we set off become a star. This is not science. This is history."
The telemetry, tracking, and command center simultaneously received all the boundary data transmitted back by Pioneer. Yu Ying discovered a key characteristic while analyzing the pulse oscillation data sent by Lu Yunfei: the electromagnetic oscillations detected by Pioneer in the transition zone had frequencies completely identical to the synchronization pulse frequencies of all nine nodes of the solar network. Charged particles in the solar wind generated synchronous oscillations as they passed through the electromagnetic framework formed by the network nodes.
Yu Ying presented the conclusion to Zuo Cheng.
The boundaries of the solar system's web are not physical boundaries. The web transforms the entire heliosphere into a resonant cavity. The entire solar system is like an instrument tuned by the web. Everything humanity does in the solar system—the ignition of every spacecraft's engine, the orbital correction of every satellite—leaves echoes within this resonant cavity that can be perceived by the web.
Zuo Cheng remained silent for a long time after hearing this conclusion. Then he said something.
"So the founders waited for forty years on the outskirts of the solar system, not because they were waiting for humans to build spaceships. It was because they were waiting for a sufficiently large echo within this resonant cavity—large enough to be heard by the Centaurus node."
Yu Ying looked at him. Zuo Cheng continued, "The Pioneer's engines have been vibrating in this resonant cavity for four years. There hasn't been such a strong echo in four billion years. Now, Centaurus is hearing it. Their heartbeat signals have been getting stronger for seven months. It's not a coincidence."
A note popped up on the system panel: "Web Boundary Sensing Capability Activated. The Solar System Web can now detect any object entering its heliosphere, from a spaceship to a speck of interstellar dust. This is the first step in making the Web a civilization's defense system. When the founders initially designed the Web, its primary purpose was not communication, but early warning."
Yu Ying looked at the note and said softly.
"The founders didn't build the web to make phone calls. They built it to hear if anyone was knocking on the door."
Zuo Cheng nodded. Humanity spent four billion years learning to knock. Now it's time to open the door.
Shen Yiming wrote the last log of the Pioneer Expedition on the border. No. 783.
We set out from Earth, passed Mars, paused on the icy shell of Triton, and traversed the debris of the Kuiper Belt. Now we stand at the edge of the solar system. Before us lies interstellar space. Behind us, the star is our home. All mission objectives have been achieved. Humanity has reached every corner of the solar system. Requesting permission to return.
The signal travels from the top of the heliosphere back to Earth, passing through a full-topology link of nine nodes in a network, with a delay of less than one femtosecond.
Zuo Cheng's reply consisted of only four words.
Welcome home.
When Chen Hao heard those four words at the control center, he put down his coffee cup. He glanced at the 27-meter timeline on the wall. At the very end, a new card had appeared. It bore Shen Yiming's log number 783 and Zuo Cheng's reply. The two cards were side by side, separated by four billion kilometers and four billion years. Chen Hao said to Han Lu beside him, "From the incubator to the edge of the solar system, eleven years." Han Lu replied, "From two people to ninety-two neighboring civilizations, also eleven years."
Pioneer changed direction. The plasma engines reignited, directing thrust towards the interior of the solar system. The acceleration phase lasted six hours.
After shutting down the engine, Ji Beihang glanced back out the rear window. Outside lay the direction of interstellar space from that point onward. He saluted in that direction. Then he stuck a note in the corner of the cockpit.
I will be back. Next time, not in a spaceship. Next time, I'll be piloting a spaceship I designed.
Shen Yiming saw the note and added a line below it.
Next time, I won't be alone. Next time, I'll be with all of humanity.
Pioneer began its return journey. Behind it lay the edge of the solar system. Ahead lay a star 4.5 billion kilometers away, growing brighter. It was still just a star. But with each passing day, it would become a little brighter than the day before.