Chapter 4-2 The Power of Sound Waves
The transmission of energy and the effects of resonance cannot occur without a medium. Therefore, we will now dedicate some space to introduce the ubiquitous sound waves and light waves. Unlike our physical bodies, sound and light possess extraordinary transmission and penetration abilities, capable of carrying information and energy. They serve as important links between humans and higher dimensions. Similarly, if higher dimensions wish to influence humans, they must do so through these mediums.
We perceive sound and light through sound waves and light waves.
All sound waves are mechanical waves, which must rely on a medium to propagate and cannot exist in a vacuum (such as outer space). The frequency range of sound waves is wide, and the vocal and auditory frequency ranges of humans and animals differ. The normal human ear can hear frequencies ranging from 20Hz to 20,000Hz, and the vocal frequency ranges from 85Hz to 1,100Hz (although significant variations exist among individuals of different genders, ages, and genetic backgrounds). Scientists refer to sound waves with frequencies below 20Hz as infrasound and those with frequencies above 20,000Hz as ultrasound (Figure 4.3).
Figure 4.3: Infrasound and Ultrasound
We call the distance a wave travels in one oscillation period its wavelength. The basic unit of measurement for wavelength is meters (m). According to the wavelength formula: λ = v/f (λ - wavelength, v - wave speed, f - frequency), where v for sound waves is 340 meters per second. Therefore, λ > 17m is the wavelength of infrasound, and λ < 0.017m is the wavelength of ultrasound. The lower the frequency, the longer the wavelength; the higher the frequency, the shorter the wavelength. All objects have a "natural frequency". Generally speaking, the greater the mass of the unit, the lower its natural frequency and resonant frequency. For example: rock < bone < muscle < blood.
- Infrasound
Infrasound has very low frequencies. Despite vibrating fewer than 20 times per second, its wavelength is long enough to propagate over great distances with minimal attenuation. Infrasound is highly penetrating due to minimal absorption by the atmosphere, making it capable of traveling thousands of kilometers virtually undisturbed, with negligible energy loss. Frequencies below 10 Hz can traverse mountains and oceans, penetrating materials such as reinforced concrete over several meters with ease.
Natural phenomena such as earthquakes, tsunamis, volcanic eruptions, storms, lightning, whirlpools, magnetic storms, auroras, and tornadoes can all generate powerful infrasound waves. Human activities such as rocket launches, missile flights, nuclear explosions, ship navigation, speeding cars, and the shaking of tall buildings and bridges can also produce infrasound. Even devices like blowers, mixers, loudspeakers, and certain sharp friction noises can generate infrasound.
In 1883, the eruption of Indonesia's Krakatoa volcano produced massive infrasound waves that circled the earth three times, with the infrasound being detected thousands of kilometers away from the volcano. This was the first recorded infrasound by humans. In 1986, the explosion of the American space shuttle Challenger generated infrasound waves that lasted 12 hours and 53 minutes.
Although the human ear cannot hear infrasound, it significantly impacts the human body. Human organs have subtle and rhythmic pulsations, typically in the range of 2-16Hz, with larger masses having lower natural frequencies; for example, the brain pulsates at 8-12Hz, internal organs at 6-9Hz, and the skeleton possibly at even lower frequencies. When infrasound falls within the natural frequency range of human organs, it can cause these organs to resonate, leading to functional disorders, elevated blood pressure, and other physical discomforts. High-intensity infrasound can cause strong resonance in the human body, leading to irreversible harm such as persistent vomiting, difficulty breathing, muscle spasms, nervous breakdowns, loss of consciousness, deformation of internal organs, and ruptured blood vessels.
Infrasound is known as the "silent killer" in military applications. Whether the enemy is hiding behind several meters of reinforced concrete, sitting in a tank, or concealed in a submarine deep underwater, infrasound weapons can easily be "lethal with one strike." In the mid-1960s, the French Ministry of Defense secretly commissioned the development of this new "weapon of mass destruction" by Vladimir Gavreau, who later became known as the "father of sonic weapons". The existence of this research came to light due to a 1986 infrasound weapon test experiment. Due to a technical oversight, the infrasound waves escaped the laboratory, causing the mysterious deaths of 30 residents 16 kilometers away ("they turned into bloody corpses within seconds"). In 2001, Gavreau's military robot "Infrasound Smart Warrior" was unveiled. It can "instantly kill all enemies within a ten-kilometer radius", making it a threat to sea, land, and air targets. Currently, infrasound weapons have evolved into "organ-type" infrasound weapons and "nerve-type" infrasound weapons, which respectively match the resonance frequencies of human internal organs and the brain's alpha rhythms. Both types can cause severe discomfort and even death. According to online sources, there are suspected cases of the United Kingdom and Israel using sonic weapons to quell regional disturbances (the authenticity of these cases cannot be verified).
Due to unresolved issues with directional propagation and intensity regulation of infrasound, it has not been publicly deployed in actual combat. We hope that it never becomes practical because its widespread use in warfare would bring a disaster more terrifying than nuclear strikes.
Understanding that objects with higher hardness (mass) have lower natural frequencies and are more prone to resonance explains why sometimes muscle damage is not apparent, yet fractures or bone cracks occur after an injury. Similarly, bridge collapses due to resonance are not uncommon. It's not the weight of the objects that exceeds the bridge's load capacity, but the infrasound generated by vehicles crossing in a convoy that resonates with the bridge structure, causing "fatal damage" to the reinforced concrete.
Infrasound might explain many "unsolved mysteries" featured in books for young readers, such as the enigmatic world's top ten forbidden places like the "Bermuda Triangle" and the "Dragon's Triangle" near Japan. Here are a few real-life cases.
In 1890, a sailing ship named the "Marlborough" mysteriously disappeared while sailing from New Zealand to England. 20 years later, it was found on the coast of Tierra del Fuego, with everything on board remarkably preserved, including crew members in their "original positions" (their bodies and skeletons were intact, though internal organs likely suffered initial damage).
In 1948, a Dutch cargo ship named the "Ulangemeach" encountered a sudden sea storm while passing through the Strait of Malacca. When rescuers arrived, they found all the crew members dead under mysterious circumstances. Investigators attributed the maritime disaster to infrasound waves generated by the storm and the turbulent sea.
Similarly, during World War I, a German warship mysteriously lost contact. When rescuers arrived, they found the sailors' bodies with no visible injuries, but autopsies revealed that all the sailors' internal organs had ruptured. It was discovered that a powerful earthquake had occurred underwater at the time of the incident. Although the sailors could not hear the infrasound waves generated by the earthquake, the waves were powerful enough to instantly shatter human internal organs.
Do you remember the terrorist attack on New York's Twin Towers on September 11, 2001, 20 years ago? The planes hijacked by terrorists hit the Twin Towers at a speed of 790 km/h. Rather than exploding immediately upon impact, the buildings burned for 20 minutes before collapsing within seconds. Many researchers have examined this as a highly precise "targeted strike": the North Tower was struck between floors 94 and 98, while the South Tower was hit between floors 78 and 84, separated by 18 minutes. However, it is hard to imagine how the impact and subsequent fires could cause both towers to turn into "ashes". It is possible that regardless of which specific floor the planes hit, the intense infrasound waves generated by the impact resonated strongly with the steel framework of the buildings (78,000 tons of dense steel columns, with walls made of aluminum panels and glass). This resonance could have been rapidly transmitted and sustained within the steel structure, eventually leading to the collapse of the two skyscrapers beyond their load-bearing limits, turning them into "dust".
Along these lines, Biologists widely believe that 65 million years ago, a "Asteroid impact on Earth" likely caused the sudden extinction of dinosaurs. Dinosaurs were large animals, and an impact, volcanic eruptions, or rising sea levels would have given them some reaction time to survive. However, fossil evidence shows that many dinosaurs died suddenly, maintaining their feeding and walking postures, indicating they did not have time to swallow or realize the danger before experiencing a catastrophic event. Could it be that the Asteroid impact generated powerful infrasound waves that enveloped the earth and instantly "pierced" the dinosaurs' internal organs? Due to the high hardness and low natural frequency of some dinosaur bones, they were "preserved" in place.
Following this reasoning, if there were "ancient human civilizations" or similar life forms, their "flesh and blood" would not have been spared. Apart from their stone sculptures or buildings, bronze or gold and silver utensils, all "existences", including their bones (which are softer than dinosaur bones), would have disappeared without a trace, leading future generations to view them as "mysteriously vanished", as if they had never existed.
Similarly, contemporary species that survived alongside dinosaurs—such as lizards, horseshoe crabs, trilobites, bees, lungfish, sea turtles, platypuses, and certain marine life—don't necessarily possess greater vitality or higher heat resistance than dinosaurs. It's plausible that these animals survived the prehistoric cataclysm simply because their visceral resonance frequencies were lower than those produced by the disaster's infrasound waves, allowing them to effortlessly evade a "catastrophic and irreversible" event.
- Ultrasonic Waves
The prefix "ultra" in ultrasound comes from its frequency range exceeding that of human hearing. The mechanical waves that human ears can detect have wavelengths between 2 centimeters and 20 meters. Therefore, scientists refer to mechanical waves with wavelengths shorter than 2 centimeters (or 1.7 centimeters, corresponding to a frequency of 20,000 Hz) as "Ultrasound". Ultrasound travels farther in water than in air due to its short wavelength. However, in air, it is easily absorbed and scattered, making it less effective over long distances compared to audible sound and infrasound. In practical applications, mechanical waves with wavelengths shorter than 3.4 centimeters (corresponding to 10,000 Hz) can be considered ultrasound. Ultrasound is widely used in medicine and industry for cleaning, fragmentation, sterilization, cutting, welding, and drilling, and more.
Ultrasound waves are very short, only a few centimeters or even thousandths of a millimeter. Compared to other waves, ultrasound has many characteristics, such as severe scattering and poor penetration. However, when acting on a liquid medium, it can alter the medium's original density, creating small cavities. These cavities quickly expand and collapse, causing intense collisions between liquid particles, resulting in effective "stirring". This phenomenon allows two incompatible liquids (such as water and oil) to emulsify, accelerating solute dissolution. This principle is used in ultrasonic cleaning, which can clean jewelry, glasses, and watch parts.
In dry winter months, if ultrasound is passed into a water-filled container, the mechanical waves will break the water into small droplets, which a fan can then disperse into the room to increase humidity—this is the principle behind a humidifier. In medical treatment, diseases like pharyngitis and bronchitis are hard to treat with intravenous medications alone. Using the humidifier principle, the medication can be nebulized for the patient to inhale, improving treatment efficacy—this is the "medical nebulizer".
The effects produced by ultrasound traveling through a medium can trigger various human responses. The mechanical action of ultrasound can soften tissue, enhance permeability, boost metabolism, promote blood circulation, stimulate the nervous system, relieve inflammation, and activate cells, thus having unique therapeutic significance. Certain substances within tissue cells, through the micro-massage of ultrasound, can cause cells to rotate and rub, promoting metabolism, accelerating blood and lymph circulation, and softening hard connective tissue.
Ultrasound treatment in hospitals began in the 1940s and has since been widely used for cosmetic purposes, such as removing blemishes and wrinkles and improving skin texture. Ultrasound surgery, which can be performed without incisions or scars, enables external operations on internal tissues. This is the famous "focused ultrasound surgery". It works by passing low-energy ultrasound waves through the body and focusing them on the affected area. When the ultrasound waves converge at a point, the targeted tissue undergoes coagulative necrosis or direct ablation, effectively destroying tumor cells and treating cancer.
In our routine physical examinations, B-mode Ultrasound is a typical example of an ultrasound examination. Other similar ultrasound examinations include Color Doppler Ultrasound, M-mode Ultrasound, and Contrast-enhanced Ultrasound. These ultrasound examinations can obtain multiple cross-sectional images of the examined organs, allowing doctors to visually observe their morphology.
For many years, ultrasound surgery has been widely used in the treatment of stone diseases. Ultrasound can not only accurately detect internal organ stones but also "shatter" the stones non-invasively using "Ultrasonic Lithotripsy", reducing the patient's surgical pain.
In nature, many animals are naturally adept at using ultrasound to locate prey and obstacles. For instance, bats have very poor eyesight and are mostly active at night. They can produce ultrasound using their mouth, nose, and even by flapping their wings. If these ultrasound signals encounter objects along their flight path, they immediately reflect back. Upon receiving the returned signals, bats can efficiently and swiftly hear, see, calculate, and navigate around obstacles. Bats can also detect water ripples caused by fish underwater and fly close to the water surface when hunting. Even more astonishing is their ability to detect stationary moths and sleeping dragonflies using ultrasound, making bats some of nature's most efficient predators (Figure 4.4).
Figure 4.4: Vocalization and auditory frequencies in humans and animals
Dolphins, marine mammals known as "ultrasound hunters", are highly intelligent and adorable. Each dolphin has its unique language and uses ultrasound with different frequencies to communicate with one another. Baby dolphins stay with their mothers until they are six years old. Studies have shown that an adult dolphin's intelligence is comparable to that of a 6-year-old human child, which is why dolphins often interact amicably with humans in marine parks. Dolphins can emit ultrasound pulses as high as 150,000 Hz using their jawbones. These pulses travel hundreds of meters in water and then reflect back to the dolphins' ears. By analyzing the echoes, dolphins can determine the location and shape of objects and "perceive" the material of different items, such as distinguishing between rocks and starfish. This method of ultrasound sensing is called echolocation, or "sonar". This "sonar" can also detect the skeletal structure of humans, and there are records of dolphins fighting sharks to save drowning humans. Dolphin leaders can organize their groups for coordinated activities and even collaborative hunting.
