Preventing sound from being heard by anyone on Earth completely is a challenging task, given the nature of sound waves and the vastness of our planet. Sound waves propagate through mediums such as air, water, or solids, and they can travel long distances. However, here are a few methods that can help minimize sound transmission:
Soundproofing: Soundproofing techniques can be employed to reduce the transmission of sound waves. This involves creating barriers or using materials that absorb, dampen, or block sound. For example, constructing double walls with insulation, using acoustic panels, sealing gaps and cracks, and using materials with sound-absorbing properties can help reduce sound transmission.
Distance and physical obstacles: Sound waves become less audible as they travel over long distances. Placing physical obstacles like hills, buildings, or walls between the source of sound and the intended recipient can help reduce the sound reaching them.
Underwater or underground transmission: Sound travels differently underwater or underground compared to in the air. Utilizing these mediums can help restrict sound transmission. For instance, if sound is transmitted underwater, it may not reach the surface or be heard by people on land.
Active noise cancellation: Active noise cancellation technology uses destructive interference to cancel out unwanted sounds. By emitting sound waves with the same amplitude but opposite phase to the incoming sound waves, they can effectively cancel each other out, reducing the overall sound level. However, this method is generally effective in localized areas rather than preventing sound from being heard across the entire planet.
It is important to note that completely preventing sound from being heard by anyone on Earth, regardless of technology, seems highly unlikely. Sound waves can travel long distances and can be reflected, refracted, or diffracted by various objects and mediums. Moreover, even if sound could be controlled locally, it would be practically impossible to prevent all sound from reaching every corner of the planet simultaneously.
While technological advancements may improve soundproofing and noise cancellation techniques, achieving a complete absence of sound transmission on a global scale remains highly improbable based on our current understanding of sound and its behavior.