Once We Lived in Nanjing

The programming issues continued until this Friday, and Ban Xia really couldn't figure it out, so Wang Ning asked a friend to bring in a communication expert from Huawei.

Seeing the code written by Bai Zhen, the expert's face scrunched up.

"In my memory, when I was very young, I saw it once, as dusk was approaching and the distance was too far, only a blurry shadow was visible," the voice of a girl came from the headphones, "It was crawling on the upper floors, with long legs, just like a big black spider, the teacher said they came from the moon."

"Black Moon? OVER."

"Yes, it's the Black Moon," the girl said, "They only appeared after the Black Moon descended."

"What is the cause of the Black Moon's descent?" Bai Yang sat on the chair, holding a pen between his fingers, furrowing his brow, "It can't just appear out of nowhere, right?"

Although figuring out the cause of the apocalypse is crucial, it's uncertain whether the cause is something humans can influence or change.

What if the Black Moon discovered the Pioneer or the Voyager probe?

Do humans have the ability to retrieve the Voyager now?

Furthermore, what if it's the existence of humanity itself that the Black Moon discovered?

Do humans even have the capability to conceal an entire Earth?

Questions are questions, but there might not be answers. If a natural disaster is beyond human redemption, then even if it can be foreseen, all people can do is try to minimize the losses. Be it earthquakes or tsunamis, although they are unstoppable by mere human effort, at least people can be alerted to evacuate— but where can people run if a moon were to fall down?

Run to outer space?

That would definitely not be enough in three years, maybe three hundred years.

"Let's find a way to hide the Earth," Bai Yang said, "Miss, do you have any good ideas? OVER."

"Eh?" The other side paused, "What do you mean?"

"Just hiding the entire Earth, so the Black Moon can't find us," Bai Yang casually said, "If it can't find us, we'd be safe, right? OVER."

"Then... how about covering the Earth with black cloth?"

"Where would we find so much black cloth?" Bai Yang laughed, "The Earth's surface area is 500 million square kilometers, you would need 500 million square kilometers of black cloth, that's even more ridiculous than covering the Pacific Ocean, OVER."

Although he said this, the concept of "hiding the Earth" sparked an idea in Bai Yang—what if, and I mean what if, people could find out the real reason for the Black Moon's descent, could find out how the Black Moon found Earth, maybe this really is a method? If it's known how the Black Moon collected Earth's specific information, then people could work on erasing this information, cutting off the channels of its transmission, hiding Earth's location—

This sounds incredible.

Just like during World War II when the British used lights at night to create fake cities, misleading German bombers, using the same concept, humanity could conduct a strategic deception and misdirection on an unprecedented scale!

Hiding the entire Earth.

If the Black Moon observes Earth using visible light, then people could hide in the visible light spectrum.

If the Black Moon observes Earth using infrared light, then humanity could hide in the infrared spectrum.

Treat the symptoms with targeted solutions.

That's what Bai Yang thought.

Although it's hard to imagine what the actual operation would look like, hiding a massive sphere with a radius of 6,370 kilometers, making it disappear from the Black Moon's sight, playing a life-and-death game of cosmic-scale hide and seek—but it remains a possible solution. The future has already proven that a head-on confrontation with the Black Moon will surely be a losing battle for humanity. Since we can't beat it, can't we still hide?

Bai Yang decided to send this idea to Zhao Bowen to consider.

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Meanwhile.

A wall apart.

Wang Ning and Bai Zhen were still struggling with coding. This afternoon, a communication expert from Huawei took time out of his busy schedule to help, who was an old classmate of Wang Ning's old classmate, and happened to be on a business trip in Nanjing recently. Upon hearing their request, he came to help them out.

After looking at Bai Zhen's code, he delicately commented that no matter how much runny stuff there is, it can't pile up into a mountain of shit.

So, the professional personally took the stage, with a vigorous aura, putting in place the very first solid foundation of constipation-grade hard stool for that mountain of shit.

Once the expert was done, he left without charging, light as a feather. With a wave of his hands, he said that they were all friends here, helping out was just a small favor, a mere gesture, no need for money. He had other matters to attend to and took his leave, promising future meetings.

Bai Zhen watched his back, sighing with admiration, "If I had gone to university back then, I'd be working at Huawei today, just as carefree as him."

Wang Ning said, "With your grades of repeating grades, attending university?"

Next, the two rolled up their sleeves and worked all night, continuing to build a complete image transmission link on a second-hand 725. The expert sorted out the basics, the integrated development environment, and the compiler. Bai Zhen marveled that it was indeed the work of an industry expert – his code writing was like Marquez's "One Hundred Years of Solitude".

Wang Ning asked, "You mean his level is as high as 'One Hundred Years of Solitude'?"

Bai Zhen replied, "As incomprehensible as 'One Hundred Years of Solitude'."

The next big challenge facing them was the transmission rate.

"How fast can this thing go?" Wang Ning patted the black casing of the radio.

"We're using AFSK; I fear the speed can't be very high," Bai Zhen said, estimating it to be around 800 to 1000bps.

"How did you calculate that?"

"Based on the frequency of sound. We're turning all data, be it images or code, into sound for transmission. But there's a limit to sound frequency—the highest frequency the human ear can normally detect is 20,000 hertz, so the working range of the sound card is also this range," Bai Zhen explained. "The theoretical maximum transmission rate of a digital signal can't exceed its carrier frequency, which is 10,000 hertz, i.e., 10kbps."

"10kbps, ten thousand bits per second..." Wang Ning did a quick calculation, "Converted to kB, how much is that? Divided by 8?"

"Divide by 10," Bai Zhen corrected. "10kbps, converted into the internet speed we often talk about, is 1kB/s, one kilobyte per second. But this is a theoretical value, the highest possible speed."

"1kB per second is still just a theoretical maximum?"

"Yes, 1kB per second is an unreachable theoretical value. In real-world engineering practice, achieving a speed of 1000bps is considered quite good," Bai Zhen nodded.

"Speed of 1000bps..." Wang Ning calculated, "0.1kB/s? Every second 100 bytes? 100B?"

"Yes, a hundred B per second," Bai Zhen said. "That's the speed of data transmission."

Wang Ning realized video transmission was impossible with this speed. Not to mention viewing images, even reading novels could be problematic—it was like a throwback to the era of dial-up internet.

"AFSK is like this," Bai Zhen said. "Later, if conditions permit, we could switch to PSK modulation method which is much faster than the current one, but for now, let's just make do."

Faced with the super low internet speed of less than 1kB per second, their only choice to quickly transmit images was compression.

Extreme compression.

Compress a 10MB image down to 1MB, then further down to 10KB. In the process of compression, the image would lose 99.9999% of its information.

And a 10KB sized image would take 100 seconds to transmit using this 725 radio.

Wang Ning and Bai Zhen decided to do an experiment to see what effect the image compression and transmission would have.

Wang Ning took a photo of Bai Zhen, a head-and-shoulders portrait, 1.5MB in size.

Next, they imported it into Photoshop, first resizing it proportionally to a quarter of its original size, which halved its size. Then they performed chroma subsampling, turning a color photograph into a black-and-white one, which halved the size again. Finally, they compressed the quality; Rushing through the operations fiercer than a tiger, they found out the compression ratio was one to five.

Finally, Wang Ning displayed the photo—

His mother passed by the living room, and casually glanced from a distance.

"What is this, a Ugandan chimpanzee?"