Chapter 149: Whale Song

Chapter 149 -62: Whale Song

“If that’s the case… then our Rabbit Hole is even more important.” Wen Xiao, who had been silent, suddenly spoke up.

“If the real world is really going to be submerged by a flood, if all signals will be cut off, then at the very least, we have to ensure we can still contact each other when the disaster strikes.”

“That’s true, but… have you considered that if the flood really comes, our Rabbit Hole might not even work?”

“Huh?” Shi Zuozhou, lost in his sorrow, was taken aback. He raised his wrist and shook the bracelet on it.

“As long as this thing has power, we can communicate, right? What could possibly stop it from working?”

Yu Xian’s fingers tapped lightly on the sofa. He mulled it over for a moment before asking:

“All of our current technical solutions are essentially based on near-field communication using Bluetooth and WiFi signals, right?”

“Right.” Wen Xiao nodded.

“We mainly utilize radio waves in the 2.4 GHz band.”

“And that’s the problem.” Yu Xian gestured to the heavy rain outside.

“If it’s really a great flood, like Yiyi’s trigram predicted, that means the air will become saturated with moisture. Even worse… our devices might have to operate in shallow water or in extremely humid environments.”

He paused, then brought up the fatal piece of basic physics he was worried about:

“Water has a very high absorption rate for microwave and radio-frequency signals.”

Shi Zuozhou slapped his forehead, his expression changing in an instant.

“Holy shit! How could I have forgotten about that!”

He looked at the microwave on a table in the lounge.

“2.4 GHz… Isn’t that the same frequency as a microwave oven? We were just saying it! The reason microwaves can heat food is that electromagnetic waves at this frequency are perfect for making water molecules resonate. All the energy gets absorbed by the water!”

“Exactly. Water’s absorption rate for electromagnetic waves in the 2.4 GHz band is… extremely high.” Yu Xian nodded, his expression grim.

“In other words, water is the kryptonite of microwaves.”

He looked at Wen Xiao.

“Under normal circumstances, the effect of air humidity on Bluetooth’s transmission range is almost negligible. But in a great flood… the density of water molecules in the air would reach terrifying levels. In communications engineering, this phenomenon is called ‘rain fade.'”

“Rain fade?” Shao Yiyi blinked.

“Simply put, if the day of ‘Land Sinking into the Sea’ truly arrives, our Bluetooth, WiFi, and even cell signals won’t be able to penetrate that thick curtain of rain.”

The group fell silent, their minds racing to find a possible solution.

“But the entire field of wireless data transmission, from cell phones to satellites, relies on radio-frequency signals. Does that mean… all our work was for nothing?” Wen Xiao bit her lip, her eyes welling up.

Yu Xian frowned, his fingers drumming unconsciously on the sofa. His mind raced, pulling up knowledge from his university physics courses.

‘If we can’t use electromagnetic waves, what else is there?’

‘Light? No, visibility is terrible in a downpour. The signal would attenuate too much.’

‘Cables? Impossible. The floodwaters would cause too much impact damage, Corrosion, and breakage. Not to mention, base stations would be flooded and lose power everywhere.’

‘What else… what medium travels through water, maybe even better than it travels through air?’

Yu Xian’s gaze drifted unconsciously to Wen Xiao’s water glass on the table.

The vibration from the air conditioner vent sent tiny ripples across the surface of the water.

Vibration.

Mechanical waves.

Sound waves.

“Sound waves!”

Yu Xian snapped his head up and looked at Wen Xiao.

“Is there a way to communicate with sound waves? Water might absorb electromagnetic waves, but it’s an excellent conductor for sound. The speed of sound in water is over four times faster than in air, and the attenuation is extremely low.”

“Near-ultrasound!” Wen Xiao was suddenly on the same wavelength as Yu Xian, her eyes shining.

“I get it! It’s just like how submarines and whales can only communicate in the deep sea using sonar and Whale Song!”

“Sound?” Shi Zuozhou still looked completely clueless.

“You mean we’re supposed to grab a megaphone and start shouting? Like, ‘HEEEEY—MA-A-A-RY-Y-Y—’?”

“No, no!” Wen Xiao quickly waved her hands.

“I was thinking we could migrate Rabbit Hole to a data transmission protocol based on ‘near-ultrasound.’ It uses sound waves with a frequency between 19 kHz and 20 kHz.”

She pulled up related information on her laptop and explained to the others:

“Most adults can’t hear sound in this frequency range, but our phone microphones can pick it up easily. We can encode data into this sound wave, just like an old dial-up modem or Morse code!”

“The moment Rabbit Hole detects that the Bluetooth signal strength has dropped below a certain threshold, or if the connection fails due to environmental factors, it will automatically switch to ‘Near-Ultrasound Mode.'” Wen Xiao explained, making gestures with her hands.

“At that point, the phones and bracelets will use their speakers to send out a burst of encoded, high-frequency sound waves. Nearby devices will ‘hear’ this sound, decode it back into data, and then relay it forward using the same method.”

As Yu Xian listened to Wen Xiao’s description, a scene formed in his mind.

He pictured an apocalyptic world submerged by torrential rain. In the dark floodwaters, countless people were trapped on isolated ‘islands,’ hiding in cramped shelters while the world roared outside.

But beneath the murky surface, countless phones and bracelets, like whales in the deep sea, were emitting calls inaudible to human ears, piercing the silence to transmit coordinates and information to one another.

These sounds would pierce the rain and cut through the currents, connecting one desperate face to another, one lonely soul to the next.