anacoustic zone

The zone of silence in space, starting at about 100 miles (160 kilometers) altitude, where the distance between air molecules is greater than the wavelength of sound, and sound waves can no longer be propagated.

Related terms:

• hyperacoustic zone
• Zone of Aeration
• Benioff zone
• plastic zone
• Zone of Saturation
• Low-Velocity Zone
• shadow zone
• aerothermodynamic border
• frostless zone
• standard artillery zone