8

As others have stated here, you can hear the sonic boom of planes flying by at a fairly high altitude, ~80 000 ft. At what altitude would the sonic boom no longer be noticable at sea level? To add to that, is there any relatively "simple" method of estimating sound dissipation with altitude?

Blomma
  • 81
  • 1
  • 2
  • Interesting question. We don't hear meteors at all, meteors fly through the mesosphere, above 160,000 ft (49 km). Therefore, the hearing limit is probably somewhere between that and 60,000 ft (18.3 km), Concorde's maximum cruise altitude. – Better not tell Feb 04 '22 at 15:03
  • 1
    The larger the object, the louder the sonic boom. A supersonic bullet produces a "click" when it passes by (not that I recommend trying to experience this personally), and that click wouldn't be audible beyond a few hundred yards; the "click - bang" would become just the "bang" of the weapon firing. Given this dynamic, there won't be a single altitude that "the sonic boom" doesn't reach the surface; the altitude would be affected by the size of the aircraft involved. – Ralph J Feb 04 '22 at 17:52
  • I'm gonna say a .308 makes more than just a click at supersonic speeds. – Jpe61 Feb 04 '22 at 21:58
  • 2
    @Betternottell We don't hear meteors at all ... I beg to differ. In 2013, windows were smashed, buildings were damaged and people were injured as a result of the shockwave of a meteor near Chelyabinsk, Russia. Smaller meteors may be heard too, but the smaller the meteor, the more faint the noise it makes. Note that due to distance the sound has to travel, there is a long delay between the sighting of the meteor and the arrival of the sound. – DeltaLima Feb 07 '22 at 09:25
  • @DeltaLima I meant the usual meteors (falling stars) such as Perseides or Leonides, not exceptional meteoroids surviving the stratosphere. – Better not tell Feb 07 '22 at 11:45

2 Answers2

1

As an observer, you hear the Sound Pressure Level (SPL), which comes from a source emitting sound at a given Sound Power Level (SWL).

According to this source, the SWL of a supersonic plane may exceed 200 dB. In the same source, a formula for computing SPL a given distance is also shown.

You can find an online calculator for that here.

hopper19
  • 111
  • 2
  • 4
    Please include the formula inline. The source link is a good citation, and appropriate for extensive supporting information, but the core piece of information should be directly included in your answer and not require following the link offsite. – Max Power Feb 07 '22 at 20:56
0

Dissipation of sound waves over distance depends almost entirely on variety in both composition and density of the material it travels through. This is why vertical propagation of sound is way more restricted than horizontal. So much so in fact, that a sonic boom generated by an aircraft at high altitude clearly heard at sea level at one location, may be completely unnoticeable as the same aircraft passes over a location a hundred miles further down its flight path. The altitude is more or less insignificant, unless it is clearly way too close or clearly way too far away. It's the stuff in between that matters.