One of the important reasons why humans choose black holes as new settlements is to deeply study the structure of the universe.
This decision is not made on a whim, but is based on the profound accumulation of human beings' unremitting exploration of cosmology for thousands of years.
Black Hole City is an artificial star ring that orbits a rotating black hole. This black hole is not stationary; its spin generates powerful jets that, in conjunction with the complex dynamics of the accretion disk, create a unique oscillation pattern. Each oscillation is perceived by the residents of Black Hole City as the passage of one year.
Despite humanity undergoing countless evolutions, the deep-seated memory of seasonal changes remains ingrained within us. This memory is not only a nostalgia for our past lives on Earth but also an instinctual respect for the laws of nature.
In Black Hole City, the change of seasons no longer depends on the proximity of the sun or the tilt of Earth's rotation. Instead, it is intricately tied to the oscillations of the black hole's spinning jets. However, in the quiet and desolate cosmos, the black hole lacks any visible light source; the oscillations of the jets are merely numerical changes that are then displayed in the city's media.
The hum of anticipation filled the air as we settled into our seats in the classroom of Black Hole City. The teacher, Mr. Kincaid, stood at the front, a silhouette against the backdrop of flickering holographic images depicting swirling galaxies and radiant black holes. He adjusted his glasses and smiled at us, the enthusiasm in his voice palpable.
"Today, we'll delve deeper into why humanity has chosen black holes as new settlements," he began, pacing the front of the room. "This decision isn't just a spontaneous whim. It's rooted in thousands of years of relentless exploration and discovery in cosmology."
A hand shot up from the back of the room. It was Lyra, my newfound friend. "Mr. Kincaid, can you explain how ancient civilizations contributed to our understanding of the universe?"
Mr. Kincaid replied, nodding. "Let's start with ancient Babylon, one of the four great ancient civilizations. They were pioneers in astronomical observation. Unlike other civilizations, they didn't just build monuments; they meticulously recorded their observations."
Lyra leaned forward, intrigued. "How did they do that?"
Mr. Kincaid gestured to a holographic display that materialized beside him, showcasing ancient cuneiform tablets. "Their unique cuneiform writing system allowed them to document not only daily life but also celestial phenomena. They tracked the movements of stars and planets, laying the groundwork for future generations."
I found myself fascinated by the concept of those ancient astronomers gazing up at the night sky, much like I had done back on Earth. "So, their observations helped us develop modern cosmology?" I asked, wanting to connect the past to our current explorations.
"Absolutely, Johnson," he affirmed, his eyes glinting with excitement. "Those early observations provided us with invaluable data. Over centuries, our understanding of the universe has deepened—from simple star charts to the complex cosmological physics we study today."
Mr. Kincaid shifted the focus of the hologram to a swirling black hole. "Now, let's discuss black holes—one of the universe's most enigmatic entities. They offer us a unique laboratory to study space and time."
"What makes black holes so special?" I asked, my curiosity piqued.
He responded. "Their immense gravity distorts time and space. According to general relativity, if you approach a black hole, you experience a phenomenon known as time dilation. To an outside observer, it seems like time slows down for you. Within the event horizon, where gravity is strongest, the laws of physics as we know them may cease to apply."
"Does that mean we could travel to different universes?" Lyra chimed in.
"Exactly!" Mr. Kincaid exclaimed, his eyes sparkling with enthusiasm. "Some theories suggest that black holes could act as portals to other universes. If we could stabilize a wormhole—a hypothetical bridge between points in space and time—we might explore realms beyond our own."
The idea sent shivers down my spine. "But how would we stabilize such a thing?" I wondered aloud.
"That's one of the biggest challenges we face," Mr. Kincaid replied, his tone growing serious. "Even if wormholes exist, we have no experimental confirmation of them yet. Our understanding is still largely theoretical."
The conversation shifted back to the practical aspects of our life in Black Hole City. Mr. Kincaid leaned against the desk, his expression contemplative. "Living and researching here is both exhilarating and challenging."
I felt the heat rise to my cheeks, but I appreciated his honesty. I do have trouble keeping up with the calculations.
"Physics requires rigor," he said gently. "Remember, every number and every symbol has specific significance. Let's take the example of a small artificial black hole with a rest mass of around 10 micrograms. The calculations for it can be tricky."
"How can we create such a small black hole?" Mr. Kincaid said, brightening, "In Black Hole City, we utilize miniaturized black hole technology. We can generate black holes weighing between 0.001 grams to about 1 kilogram, and it will have a very high Hawking temperature. The evaporation process is very rapid, converting mass into light energy. In contrast, the Hawking temperature of a black hole with a mass equivalent to the sun is very low and almost undetectable."
The hologram changed to illustrate the process of black hole evaporation. "Through Hawking radiation, we can observe these small black holes evaporate. In this state, they emit energy in the form of gamma rays."
I raised my hand again. "What happens during that process?"
"When a black hole evaporates, it releases a massive amount of energy. Researchers in our city have designed experiments to capture and analyze these gamma rays using high-precision detectors. This data helps us understand the energy release patterns and, crucially, allows us to test our hypotheses."
That day, Mr. Kincaid shared a pivotal discovery that had been a hot topic in Black Hole City. "When a black hole's mass decreases to a certain threshold, it enters a state where it exchanges almost no information with the outside world. It's as if it vanishes from our reality."
"That sounds frightening!" Lyra exclaimed.
"It does sound ominous," Mr. Kincaid replied thoughtfully. "But it's also a fascinating area of study. Researchers devised a series of precise experiments to investigate this phenomenon. For example, they focused on gamma rays released during the evaporation process."
I leaned in closer, eager to absorb every detail. "And did they find something significant?"
"Yes," he continued. "They discovered that at this critical point, black holes do not simply disappear. Instead, they can split into smaller units when influenced by external forces - like a flow of neutrons."
"So, they don't just vanish," I mused, my mind racing. "They break apart instead?"
"Precisely!" Mr. Kincaid affirmed. "For example, when a charged black hole is affected by a neutron flow, it can split into two micro black holes - one retains its charge, and the other does not. Despite their differences, there's a connection between them that remains an enigma."
"But what about the interaction?" Lyra asked. "How can two black holes that are different still be connected?"
"That's where gravity comes into play," Mr. Kincaid explained, his voice filled with awe. "Gravity is one of the most fundamental and mysterious forces in the universe. It transcends time and space, weaving connections in ways we are still striving to understand.
As the lesson wrapped up, a sense of urgency washed over the room. "Before we conclude today," Mr. Kincaid said, his expression serious, "I must remind you of the inherent risks in our research. Exploration pushes boundaries, but it can also lead to unforeseen consequences."
After that, a small research ship was sent to the black hole to continue in-depth experiments. The ship was equipped with the most advanced scientific research equipment, aiming to better observe the characteristics of micro black holes through the time difference caused by the pendulum effect of the black hole. Mr. Kincaid also boarded the ship.
As the spacecraft slowly approached the black hole, the distortion of space-time around it became more and more obvious, and the power of the strong magnetic field and jet was shocking.
The teacher showed us these images remotely. At that time, his time was half as slow as ours. We watched him slowly move his equipment and photograph the beautiful high-speed streams of particles of the black hole in the X-ray band.
Just then, a notification beeped on Mr. Kincaid's communication device. He glanced at it, and a shadow crossed his face. "I have to go. There's been a situation with a research ship near the black hole."
I watched as he hurried out, an ominous feeling settling in my stomach. The classroom buzzed with whispers as we processed the news.
Days passed, and the absence of Mr. Kincaid left an unsettling void. Rumors swirled about the incident, but no one had concrete information. Then, one afternoon, a message appeared on the main screen in our classroom. It was from Mr. Kincaid, sent from the research ship.
"Universe exploration knows no boundaries," he wrote, his words echoing with hope and determination. "Even in the face of the unknown, we must pursue our quest for knowledge."
Tears pricked my eyes as I read his message. "He was always pushing us to seek the truth, no matter the cost," I whispered to Lyra.
"He believed in us," she replied softly. "Now, it's up to us to honor his legacy and continue the exploration of the cosmos."