Distance Audible from Cosmic Ray Sound

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    Cosmic rays Rays Sound
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Discussion Overview

The discussion revolves around the audibility of sound generated by a cosmic ray proton striking the atmosphere. Participants explore the theoretical implications of energy conversion from cosmic rays to sound, including calculations of intensity and distance of audibility, while considering various physical principles and assumptions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant seeks to calculate the distance sound from a cosmic ray impact would be audible, considering energy distribution and intensity calculations.
  • Another participant references the concept of air showers and provides calculations related to energy and pressure, suggesting an area of impact on Earth.
  • A participant questions the audibility of sound at a distance of 5.5 km, expressing skepticism about the efficiency of energy conversion to sound.
  • Sound intensity calculations are presented, with one participant noting the intensity in decibels and its implications for audibility.
  • Another participant corrects a mathematical expression related to sound intensity calculations.
  • A participant raises the idea that particles may travel faster than sound, potentially creating sonic booms, and expresses difficulty in finding a relevant equation.
  • One participant offers a speculative guess about energy dissipation in the upper atmosphere due to density gradients.

Areas of Agreement / Disagreement

Participants express differing views on the audibility of sound generated by cosmic rays, with some calculations suggesting it may be audible while others question the assumptions and efficiency involved. The discussion remains unresolved regarding the exact conditions under which the sound would be audible.

Contextual Notes

Participants rely on various assumptions about energy conversion efficiency, atmospheric conditions, and sound propagation, which are not fully resolved. The calculations depend on specific definitions and parameters that may influence outcomes.

SpitfireAce
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this isn't HW, it is more for myself, I don't want answers or links to arvix papers... I am stuck and I just need something to help me proceed... a 10^20 ev proton strikes the atmosphere a km up and creates a vertical down to the ground, the energy is evenly distributed along this vertical, assume all the energy is converted to sound, up to what distance will this sound be audible... here's where I am... I think I want to find the intensity and see what it is at some distance away from the vertical... Intensity=Power/Area... for area I use (2r)(pi)(h)+(2pi)(r^2)... is this right? now I don't know how to get the power, do I just do Energy over time where the time is the time it takes the particle to travel a km, or do I use some other equation for power (I looked through some... I found it in terms of sound pressure, and then the sound pressure is in terms of particle velocity, angular momentum, or displacement, I am assuming this refers to the air particles, and I am not sure how to get any of these from energy) Any help would be greatly appreciated, it doesn't have to be eloquent, anything that I can use! I wanted to do this by myself but searching for reliable explanations of formulas on the internet is so frustrating =(
 
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http://en.wikipedia.org/wiki/Air_shower_(physics)

An air shower caused by one cosmic ray, can be "many kilometers wide."

The cosmic ray of energy E=1020 eV equates to 1.6 x 108 ergs. Take the area impinging on Earth to be A=100 km2, i.e., 1012 cm2. The pressure on Earth, having been mediated through interactions in an atmospheric cone (V=Ah/3, where V is its volume and h is its effective height, ~10 km=106 cm), is much less even than the the following consideration, which assumes an efficiency of 100% for energy cascading:

p=3E/Ah=5 x 10-10 dyne/cm2
 
Thanks a lot Loren =)
according to you're calculations, the sound should still be audible (by ear) to someone about 5.5 km away from the vertical... which sounds too good, even with the 100% energy to sound transfer... is there some way to make this more exact?
 
At f=1000 Hz, defining zero decibels as z=10-12 W/m2 and with p=5 x 10-10 dyne/cm2, I figure the sound intensity in decibels to be:

log10(pf/z)=27 dB

barely audible, even at 100% efficiency and in the most audible range.
 
Just one correction, the last equation should read

10log10(pf/z)=27 dB
 
wouldn't the particles be going faster than sound and emitting sonic booms and such... I can't find one equation that describes this
 
A guess.

The slight density gradient of the upper atmosphere would dissipate particles' energy gradually since their equivalent phonon wavelength is negligible to intermolecular distances there.
 

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