phonosphere

The phonosphere is a hypothetical layer of Earth's atmosphere where sound waves can propagate over extremely long distances. It is conceptualized as being located in the upper atmosphere, above the region where most weather phenomena occur. The existence of the phonosphere is theorized to be a result of specific atmospheric conditions, such as temperature and pressure gradients, that can refract sound waves and prevent them from dissipating quickly.

While not a formally recognized atmospheric layer like the troposphere or stratosphere, the concept of the phonosphere has been explored in the context of acoustic phenomena. Historically, observations of unusually far-reaching sounds, such as volcanic eruptions or large explosions, have led to speculation about such a layer. These sounds might have been ducted or channeled by atmospheric conditions, allowing them to travel much further than typically expected.

The exact altitude and characteristics of the phonosphere are subjects of theoretical discussion rather than empirical measurement, as directly detecting and mapping such a region for sound propagation is challenging. Factors like atmospheric density, wind patterns, and temperature inversions at high altitudes are believed to play a crucial role in its potential formation and effectiveness. The phonosphere remains a concept primarily of interest in atmospheric acoustics and the study of long-range sound propagation.