Sounds Produced By Meteors
There are three main types of sounds associated with meteors:
- Sonic Boom – the accumulation of sound waves emitted from any object travelling at greater than the speed of sound (~343 m/s), which arrive to the observer as a loud “boom”. Meteoroids enter the atmosphere at speeds ranging from 10 to 50 km/s and often maintain supersonic flight to an altitude of less than 20 kilometers above the ground. The sonic boom produced at these lower altitudes often reach the ground, and people within the immediate area of the fireball often report hearing a loud boom or booms, a few minutes after a fireball is witnessed.
- Terminal Sounds – The arrival of meteorite fragments, (travelling at subsonic speeds) is often accompanied by a unique sound, which is described by witnesses, in the few seconds before they hit the ground. This sound occurs after the boom and can only be heard within a short distance of where the meteorites land (typically within 100 meters). Sometimes the thud of the meteorite impacting the ground is also heard at the end of the terminal sound. We have compiled here a colorful list of descriptions of terminal sounds, from Frank Cressy’s book, “From Weston To Creston, A Compendium of Witnessed US Meteorite Falls 1807 to 2016”:
- “hissing sound, compared to that of a of an engine blowing off steam” – 32kg mass, Allegan, Michigan, USA (1899)
- “loud noise resembling that of a buzz saw” – 3.2kg mass, Andover, Maine, USA (1898)
- “peculiar humming or singing noise, like an airplane flying high. … It changed to a whizzing noise and ended in a swish and a thud.” – 265g mass Athens, Alabama, USA (1933)
- “whizzing like a steam-saw going through a plank” – 5.9kg mass, Bath Furnace, Kentucky, USA (1902)
- “strange whistling sound” – 960g mass, Berthoud, Colorado, USA (2004)
- “the chopping sound made by a helicopter, but changing pitch as it approached” – 1.5kg mass, Burnwell, Kentucky, USA (1990)
- “whistling noise reminding him of an incoming mortar round” – 1.4kg mass, Claxton, Georgia, USA (1984)
- “whisting of bullets” – 200g mass, Deal, New Jersey, USA (1829)
- “there were shattering fragments, with a loud sound, prrrr! …it fell from the sky and we were over there, the sound was just on this side only and it was continuous like a passing airplane woooo” – Kombuini, Kenya (2020)
- Photoacoustic sounds – Another type of sound is sometimes described by witnesses, as a popping, swishing, or sizzling sound, concurrent with the observation of the meteor (at the same time as the visible meteor). The effect is not fully understood, but scientists have theorized that the sound comes from high frequency light pulsations, which induce vibrations in the environment surrounding the observer (Spurny, 2015).