Back to Search
Start Over
Photoacoustic Sounds from Meteors
- Source :
- Scientific Reports
- Publication Year :
- 2017
- Publisher :
- Springer Science and Business Media LLC, 2017.
-
Abstract
- Concurrent sound associated with very bright meteors manifests as popping, hissing, and faint rustling sounds occurring simultaneously with the arrival of light from meteors. Numerous instances have been documented with −11 to −13 brightness. These sounds cannot be attributed to direct acoustic propagation from the upper atmosphere for which travel time would be several minutes. Concurrent sounds must be associated with some form of electromagnetic energy generated by the meteor, propagated to the vicinity of the observer, and transduced into acoustic waves. Previously, energy propagated from meteors was assumed to be RF emissions. This has not been well validated experimentally. Herein we describe experimental results and numerical models in support of photoacoustic coupling as the mechanism. Recent photometric measurements of fireballs reveal strong millisecond flares and significant brightness oscillations at frequencies ≥40 Hz. Strongly modulated light at these frequencies with sufficient intensity can create concurrent sounds through radiative heating of common dielectric materials like hair, clothing, and leaves. This heating produces small pressure oscillations in the air contacting the absorbers. Calculations show that −12 brightness meteors can generate audible sound at ~25 dB SPL. The photoacoustic hypothesis provides an alternative explanation for this longstanding mystery about generation of concurrent sounds by fireballs.
- Subjects :
- Physics
Sound (medical instrument)
Millisecond
Brightness
Multidisciplinary
010504 meteorology & atmospheric sciences
Meteoroid
Acoustics
Acoustic wave
01 natural sciences
Electromagnetic radiation
Article
Atmosphere
0103 physical sciences
010303 astronomy & astrophysics
Energy (signal processing)
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 20452322
- Volume :
- 7
- Database :
- OpenAIRE
- Journal :
- Scientific Reports
- Accession number :
- edsair.doi.dedup.....f9215762acc728fad27f62f3188c8ac8