Can Auroras Produce Audible Sounds?

[Ivan Seeking]

Auroral sounds
A controversial question concerning auroras is whether or not they can be heard by an observer on the ground. It has been debated for several centuries, but no instrumental, objective measurements of audible sound created from auroral displays have ever been made, despite several attempts with highly sensitive microphones. Still, many people claim to have heard auroras [continued]

http://www.northern-lights.no/english/what/sounds.shtml

 

[Azael]

If auroras made sounds I am pretty sure it should have been picked up by the space phycis research center in kiruna sweden.
I have seen hundrads of auroras myself and never once did I hear any sound. But I think it would be easy to imagine hearing a faint sound when watching a aurora because they look like they should make cracking and sparkling sounds.

 

[Ivan Seeking]

There have been reports, reports that I have never confirmed or debunked, which claimed that humans, or at least some humans are sensitive to one or a range of microwave frequencies; that this can be used to produce the sense of audible clicks in a targeted individual if directed properly. The story was that the KGB was trying to use this to develop a form of secret communication. But, as I said, I have never seen this confirmed in any sense by a reliable source. Still, as I understand things, the aurora are very active in this range and it came to mind - not to be taken too seriously, it's just a thought.

 

[zoobyshoe]

I saw an aurora once when I lived in Minnesota and it made a rare excursion that far south. Didn't hear a thing, though.

 

[Azael]

if I still lived in northern sweden I would snop around to se if there is any sami myths about sound from northern lights. To bad I don't :(

 

[matthyaouw]

It'd have to be pretty damn loud to propagate from the thermosphere eh?

 

[Ivan Seeking]

I wonder if this could be a subtle manifestion of synethesia.

 

[zoobyshoe]

I wonder if this could be a subtle manifestion of synethesia.

Not exactly synaesthesia, but some people's auditory processing centers might be sensitive to something put out by the auroras such that it manifests as sound to them. Something like a direct EM stimulation of the auditory circuits of their brains.

 

[DavidK]

I grew up in a small town north of the polar circle, and have seen many auroras. I have never heard them making any sounds. My grand father, however, swears he has heard sounds which were fully correlated to the movement of the aurora. According to him, the sounds are very faint and can not be heard if there is to much surrounding noise.

Here is a link to the Swedish Institute of Space Physics where this phenomenon is discussed.

http://www.irf.se/norrsken/Norrsken_noise.html

 

[Ivan Seeking]

Not exactly synaesthesia, but some people's auditory processing centers might be sensitive to something put out by the auroras such that it manifests as sound to them. Something like a direct EM stimulation of the auditory circuits of their brains.

Well, that's the sort of thing that I was alluding to with the KGB story, but I don't know if this is really possible.

 

[Ivan Seeking]

I grew up in a small town north of the polar circle, and have seen many auroras. I have never heard them making any sounds. My grand father, however, swears he has heard sounds which were fully correlated to the movement of the aurora. According to him, the sounds are very faint and can not be heard if there is to much surrounding noise.

Here is a link to the Swedish Institute of Space Physics where this phenomenon is discussed.

http://www.irf.se/norrsken/Norrsken_noise.html

Thanks DavidK.

Something else that keeps bugging me is the idea that since people can't be hearing what they see where they see it, could the aurora be affecting the local atmosphere in some other way? With Sprites, Jets, Starters, ELVES, Tigers,

http://thunder.nsstc.nasa.gov/bookshelf/pubs/sprites.html
http://www.eurekalert.org/pub_releases/2005-01/agu-ccc011705.php

and now Black Auroras,
https://www.physicsforums.com/showthread.php?t=109501

it seems to me that if people think they are hearing something that they can't be, then perhaps other related but secondary phenomena might be involved. For example, the dark leader stroke in lightning comes to mind - you can't see it but you can sometimes hear it. Being that the aurora are a highly energetic and complex phenonena, it seems to me that it could be that other processes are creating sound that can be heard by the observer. And this could explain the apparent paradox of propagation speeds. Also, if the effect is highly directed and relatively rare, it might be sheer luck to be at the right place and time.

 

[zoobyshoe]

Well, that's the sort of thing that I was alluding to the KGB story, but I don't know if this is really possible.

Well, someone linked to a story here a few months ago about an inventor who came up with a way to project audible voices into people's heads with ultrasound. I read the link, and googled some other places the story had been printed, and it looked legit. You have to be standing in exactly the right spot to hear it, and someone right next to you won't hear it. But all they said was that ultrasound was the medium, and beyond that described nothing of how it worked.

No one much paid attention to the thread, as I recall, not too many comments.

 

[Ivan Seeking]

I was talking about microwaves as per your reference to EM inducing electifical activity in the brain. Do you know of any verified examples of EM causing a false sense of sound?

 

[zoobyshoe]

I was talking about microwaves as per your reference to EM inducing electifical activity in the brain.

I understood that. I was just improvising on the notion of it being possible by any means at all. Which it seems it might be.

Do you know of any verified examples of EM causing a false sense of sound?

Only thing I've heard of is the Neurophone, but that seems to require direct contact with the skin. I don't know if it's been confirmed to work, but I've never run across a debunking of it either. Apparently it was demonstrated on TV in the 60's.

 

[Ivan Seeking]

I understood that. I was just improvising on the notion of it being possible by any means at all. Which it seems it might be.

...ah, I see...

 

[Ivan Seeking]

Only thing I've heard of is the Neurophone, but that seems to require direct contact with the skin. I don't know if it's been confirmed to work, but I've never run across a debunking of it either. Apparently it was demonstrated on TV in the 60's.

Hmmm, well, if it could be done at all, and assuming that they were really using EM, then it is possible that a transmitted signal of sufficient intesity could as well. But that does sound a bit fake, esp since we don't see anything using the effect, and the KGB stuff is of course all highly suspect.

 

[zoobyshoe]

Hmmm, well, if it could be done at all, and assuming that they were really using EM, then it is possible that a transmitted signal of sufficient intesity could as well. But that does sound a bit fake, esp since we don't see anything using the effect, and the KGB stuff is of course all highly suspect.

There's no reason I can think of that some particular frequency couldn't directly affect the brain if all we're talking about is a rudimentary noises. It could be we all are affected by this frequency briefly once in a while and don't even know it since the noise effect is soft and can be mistaken for anyone of a number of background noises. The aurora may be the only sustained natural source of this range and many people could be insensitive to it altogether.

Your notion about secondary effects is also a possibility. Were the aurora somehow leading to ultrasonic phenomena these could be "heard" as some kind of audible noise by the right person in the right place by the same mechanism, whatever it is, that ultrasound becomes audible in that guy's invention.

 

[Ivan Seeking]

Oh, I know what you are talking about with the ultrasound. I think he used beat frequencies to bring the combination of tranmistted sound waves to an audible level - the beat frequency is the difference between the frequencies of two different waves that combine.

 

[Ivan Seeking]

There's no reason I can think of that some particular frequency couldn't directly affect the brain if all we're talking about is a rudimentary noises.

It becomes more a matter of showing why it could be true. But human hearing is incredibly sensitive, and the electrical signal evenually generated and finally perceived as sound must be extremely small. It seems easy to imagine that some EM signals of sufficient amplitude might affect this.

 

[zoobyshoe]

It becomes more a matter of showing why it could be true. But human hearing is incredibly sensitive, and the electrical signal evenually generated and finally perceived as sound must be extremely small. It seems easy to imagine that some EM signals of sufficient amplitude might affect this.

I'm thinking more on the lines of the EM frequency affecting one of the various parts of the brain that process hearing and producing a false, but authentic sounding, noise. The biggest block in the way of this is the skull which scatters EM. However, if, like the neurophone, the route to the brain were through skin nerves into the brain, the skull would be bypassed.

Someone posted an interesting article in Mind and Brain a few weeks back about how when a sound accompanies touch, as when you produce a sound by rubbing your finger on the rim of a wine glass, both the sound and touch are processed in the same part of the brain (one that is normally only used to process either sound or touch, I forget which). So, if an EM signal somehow directly affected touch nerves in the skin at a special and specific frequency it might produce a synesthetic kind of sound as well.

 

[zoobyshoe]

Oh, I know what you are talking about with the ultrasound. I think he used beat frequencies to bring the combination of tranmistted sound waves to an audible level - the beat frequency is the difference between the frequencies of two different waves that combine.

This makes sense because you could produce any frequency you wanted with the beats from two separately inaudible ultrasound frequencies. Beats are always of a lower frequency than the two contributing frequencies.