The Hum

Introduction

Since the early seventies many people have reported hearing an irritating, low frequency noise for which no source can be found[1]. It is variously described as sounding like an idling diesel engine, a distant twin-engined aircraft or a large fan or pump. Without exception the people affected by it complain it disturbs their sleep. They have difficulty getting to sleep, they get woken up during the night or wake up feeling exhausted. Others find difficulty concentrating, some have felt physically sick or felt vibrations throughout their body. Virtually everybody this noise affects has been through the same process; they go round the house turning appliances off, when everything is off and it is still there they turn everything off at the mains, when no cause can be found in the house they take to the street in the early hours wandering to and fro trying to get closer to the source; it's direction impossible to tell. Once this sound has entered your consciousness it is impossible to ignore and will plague the rest of your days. Although these occurrences have been investigated by the authorities and scientists no definitive explanation has ever been found[19].

Initial reports seemed to appear in clusters: Bristol, UK[2] being one of the first; Taos, New Mexico[3] another and Auckland, New Zealand[4] also. These clusters still happen, complaints in Woodland, Co. Durham[5], Swanage, Hants.[6] and Beaufort, Co. Kerry[10] have made the news recently in the the British Isles. In Canada people from Windsor, Ontario have formed a Facebook group[64]. However if you visit the forums devoted to the hum[61][62][63] you get the impression that the existence of this noise is much more widespread; that it is everywhere and that the clusters of interest are just the result of a critical number of people being affected in a certain area - then word gets around. There would seem to be countless other individuals out there suffering on their own. If your partner cannot hear it and your friends cannot hear it you might come to believe it is in your own head. Telling people you can hear a sound that nobody else can hear can have unpredictable consequences.

There would seem to be a fairly even, if sparse, distribution of people all over the world who are able to hear this sound. Of the people I have spoken to a few have heard it but it is not a constant feature in their life. It resides at the the very bottom of human hearing response, possibly below 20Hz which is regarded as a 'cut-off' for human hearing[33]. It is erroneous, however, to assume a noise below 20Hz cannot be be heard. Hearing response is measured as a curve which represents an arbitrary threshold of perception for a range of frequencies. Turn up the volume and frequencies outside this curve start to become audible. In any population you will find a range of characteristics with a bell curve distribution. Some people are just more receptive to these frequencies. It is estimated that between 1% and 10% of people can hear it.

For those who do not hear it, or are not that sensitive, it is hard to understand how it can be so unpleasant; It is a deep rumbling sound without any particular rhythm, it surges and wanes, grinding, pulsing, droning, seldom constant and it always seems loudest when you want some peace and quiet. It is not the sort of noise you can ignore, its rhythm is anything but regular; like the timpani section has been at the vodka during the interval! It's frequency is so low and ominous it puts one in mind of something massive but distant, in nature these sorts of sounds are generally the harbinger of doom such as earth-quakes or floods and I think at some level we are programmed to be alert to these frequencies. For me it ranks above any of the other commonly annoying sounds; snoring, barking dogs, roadworks or alarms, even crying babies stop sometime.

It does not even need to be heard to have unpleasant effects[36]. If you do not perceive it as sound it still affects the eardrum and can cause dizziness and feelings akin to sea-sickness. There is research to suggest that very low frequencies can have an even more pernicious effect. Experiments have shown that states of conciousness can be manipulated using magnetic or audio frequencies which match the brain's natural rhythms[31]. Beta rhythms lie in the 13-30Hz range (as, I'm sure, does The Hum) and are associated with an alert, waking state. Besides the general noise nuisance it may be entraining the brain to the waking state making sound sleep an impossibility[32]. What of the inability to concentrate reported by some? Although Beta corresponds to a waking state, when people have difficult decisions to make or problems to solve the brain likes to shift to a more meditative state which is Alpha, again it would make this unattainable. If this is reducing peoples decision-making ability it could explain an awful lot about the state of the world.

As time goes by this noise is getting louder and more and more people are being affected. It is no exaggeration to say that it ruins lives and has been the cause of at least one suicide[39]. Even those who do not realise they are affected can suffer; poor sleep being the most common effects and not one to be underestimated. Lack of sleep has been linked to behavioural problems[35] and diabetes[34] and my own experience tells me it destroys my ability to concentrate. There is potentially a huge public health concern in this and an associated sociological problem. It is time the powers that be accepted there is an issue and stop sweeping it under the carpet. It is not tinnitus, it is not 'microwave hearing', it is not psychosis or over-sensitive hearing. It is not gas pipes, aircraft, mining or the Earth's magnetic poles about to switch.

The internet is littered with theories, some more plausible than others. For the sufferer an explanation is an imperative (you have to know where it is coming from) and it would seem some would rather believe the impossible rather than have nothing to pin it on. Myself, I have no time for conspiracies but I can not believe there is no real knowledge available on the subject. Everything you read on the internet turns out to be false, misleading, not verifiable or downright fantastical. On the forums there are people pushing the same stories, time and again, of vaguely plausible explanations. A lot of effort seems to be going into keeping us guessing and it's hard to believe there isn't a cover-up. Classified or not it is time to address this issue. Lives are being ruined and there is the possibility it is having a subliminal but significant effect on society in general.

My Personal Experience

I first heard the hum in 1999. I had been driven to distraction by the neighbour's kids' horrid hardcore house music being played at unacceptable levels throughout the day. As I lay down in bed one night I could hear a soft bassy beat and assumed they were playing it quietly in their room at night. Weird, but my brother used to do it so not that unusual perhaps. However this continued when the family was away and there was no neighbour to the other side so where was it coming from? Whatever was causing it, I wanted it to stop, it was getting really irritating. I unplugged the alarm clock, I switched off the fridge, it was still there so I switched everything of at the mains. Still there! I went out walking at times when I was unable sleep trying to track it down but you have to be very lucky to get conditions still enough to have a chance of hearing it outside. So with tensions increasing with the neighbour and this extra annoyance I sold the house.

My heart sank when I started hearing it at the new place. Again I went walking in the night and eventually concluded it was the nearby school's swimming pool pumps that were causing it. It seemed to go away during the holidays. My work started to suffer, I was a systems analyst and the grey matter was desperate for a good night's sleep. I lost my job. I sold the house and rented a maisonette. Having three other neighbours around me was a distraction from the hum but ultimately just as much of a nuisance. I moved to a ground floor flat. The noise was still there. I unscrewed the electric meter from a wooden partition and padded it with cloth. It seemed to help.

I got a job as a technician and decided I could afford somewhere better. I found the most ideal place, close for transport, shops and countryside. Almost immediately I moved in I was struck with an horrendous hum. Natural sleep became impossible, I would drink myself to sleep every single night. The bathroom and kitchen became no-go areas; I think the lack of soft furnishing and reflective walls made them particularly bad. The bedroom had fitted wardrobes which seemed to amplify the noise. I took to sleeping on the couch and living off take-aways. I was lucky that I was pretty much my own boss in that job. When I regularly didn't turn in until 10:30am and fell asleep with my head on the desk at midday my employers just assumed I was burning the candle at both ends, as were they. This outfit was doomed by the credit crunch. It was doomed anyway.

From August 2009 I was unemployed. I was confined to the house all day, every day. Any motivation drained away from me. I had nothing to look forward to in this world any more; Every moment of my life, awake and asleep had become disrupted by this disgusting noise. Eventually anger started to condense from my depression and I resolved to get to the bottom of the problem. It was unacceptable to me that this should continue and decided I had to do everything I could to get it stopped.

The Quest

I had been keeping a log, on and off, ever since I moved to this house. I thought I might be able to find patterns in it which would provide clues. The only thing I could say for definite after two years was that it was louder at night and sometimes when the weather was really bad. It really was louder. Some people will try to tell you this is because there is less background noise at night but I lived on a very quiet street and I had taken to sleeping on the couch, the other rooms in the house being unbearable. I had spent day and night in exactly the same position and so I was able to judge the relative volume well.

I had been trawling the internet for six months trying to find something which made sense. I had read all the reports from Taos, Kokomo, Bristol, Largs, Auckland, Bondi, Hawaii and the rest. I had read about how notoriously difficult it is to record; that it might not be a sound at all, but heard recordings all the same[71][72][73][74]. I had read about microwave hearing[51], gas pipes, power lines, mining, gravity, and orks! Nothing really made sense, then I happened across a forum called Mast Victims[61] because they had a thread on microwave hearing. There were quite a few people who told exactly the same story as myself about turning off appliances and wandering the streets at night. On here the suggestion was that microwave transmissions were causing the hum.

The log was telling me it got louder at night. I would hear it 'switch on' at similar times, although the times would shift every few days. I was not prepared to accept that the hum had anything to do with mobile phones but then I wondered if this night-time activity might have something to do with them using the network at night for other purposes. Perhaps they also increased the power at these times? Perhaps it was the parabolic back-haul antenna that caused it? I know they have a more focussed beam. Is it somehow heating the air as it passes through? From the Mast Victims camp comes information about the high photon density of mobile signals[14]. It would appear photons can impart mechanical force at this density. The principle is used in optical tweezers for manipulating single cells[13]. Could this be a possibility?

I had exhausted the internet; I wasn't finding any new or useful information. I had a look at frequency analysis software hoping I could record it for myself, though I knew the necessary equipment was prohibitively expensive. While fiddling one day I switched the input to something other than the microphone and a band of noise appeared on the screen. I played with the settings to bring as much detail as I could out of this noise. It seemed like there might be a connection to the hum (really clutching at straws here). A portion of the time it was indistinct but where there was a definite peak followed by a trough it seemed to coincide with a loud pulse in the hum. The frequency was 4.3kHz. I swept the internet for 4.3kHz and 4300Hz. The three most interesting results were: The Internet, no kidding! This is the frequency separation of the channels on ADSL. Superimpose two signals with a certain frequency difference and there will be a resulting signal who's frequency is the difference. Don't say that, I'd have to move to the town to get fibre; Next - smart meters, I have one in my house. This one uses long-wave radio frequency for communication, 4.3kHz is in the long-wave band; The next one of interest was Cloudsat[41], a climate-change research satellite. It turns out that 4.3kHz is the optimum frequency for radar for satellites in a low-earth orbit. Since radar is microwave transmission as well I decide to give it some consideration.

I have a friend who is an amateur astronomer so I ask him does he know how to track satellites. "Piece of cake" is the reply "Stellarium"[81]. I install the software. Watching and listening for a while starts to show some coincidences. I've got a close eye on Cloudsat, it forms part of a constellation known as the "A-train". They fly in formation so as to cover the same ground as the one in front. They always seem to be in the frame when the hum is at it worst. I look back over my log and wind back time in the software. Another major culprit appears to be the International Space Station. I assume my idea that a microwave beam can produce an acoustic wave to be correct and that it is the radar instruments they are using which is the cause. I imagine the beam as a huge string stretching through the atmosphere with the signal acting as the finger which plucks it.

There is a definite correlation, for the first time I feel like I am on to something. This would explain all the secrecy, given the military involvement, and it could explain why nobody has pinned down a source. I realise I don't have enough proof for this to be considered significant. The log is a start, as it was done blind, I had no idea what the cause was until lately and I know I could demonstrate these events repeatedly to another.

Just as it seemed as if it couldn't get any worse, it did. The ISS has got a new toy, I thought, some super-powerful new radar. I hear it twice in the pub on a Wednesday night but can not verify the times. I go for dinner at a friend's the following Saturday night. During our meal, amid music and conversation, the noise cuts through. I ask my host the time, it is 10:30pm. Shortly before departure I hear it again, again I ask the time, it is midnight. The following day I check with the software and sure enough the Space Station was around. However the times of the passes were fifteen minutes early. I decide to try and spot the Space Station to verify the software. The perfect opportunity arises. I am sat at the bedroom window as night falls. I hear the hum step up. The first stars have just appeared high in the sky and attract my attention. At that moment, as I look up, a glistening fireball enters the frame. It flickers steadily across to centre and eventually disappears into the misty horizon. The sound fades. Less than a minute later Envisat was due to appear so I stuck around. I watched it rise from the east where the ISS had just gone down. I hear a crescendo in the hum. It tracks across towards the north and out of view.

Now I'm confused! The software is dead accurate but I have just heard these things as I saw them. I shouldn't have been able to hear the ISS at the same time I saw it because it was 200 km away, or at least its ground track was? Quick calculation - time taken for sound to travel 200 km is about 10 minutes. Envisat was exactly 10 minutes behind the ISS. I was actually hearing the ISS when I watched Envisat. I check the software to discover another satellite passed directly overhead just before the ISS, that's what I heard first. I go back to Saturday night to find the Space Station's closest approach, it was 300 km away, that's 15 minutes. That's it, I've got you, you bastards! This was the eureka moment. Not only have I pinned the noise on a satellite, the timing of the events indicates quite clearly that we are dealing with an acoustic wave and so any more exotic explanations (i.e. microwave hearing) can be consigned to the bin. I write a little program to give me the time for a sound wave to travel from the closest ground-track distance. I look back at my log. Some of the times I have logged are within seconds of an approach.

I felt a sense of achievement and relief at having finally cracked this puzzle but that was soon tempered as the realisation of what the future held took shape. Even if am able to get people to see the sense of what I'm saying and it is generally accepted, what is it going to take to clean up this scrapyard? My despair is condensed into the blackest of holes. I will never enjoy peace and quiet again and I will never again benefit from a good night's sleep. Furthermore, If I am not careful about this, I might just disappear before I can release this information.

I sketch a diagram of the satellite approaching and departing, imagining the radar beam creating a wave as it passes and I realise a couple of things. Since these hunks of space junk are travelling in excess of 20 times the speed of sound, the sound can not reach you before the time of its closest approach plus the time it takes to travel that distance. This ties in with hearing it suddenly switch on. Also there will also be portions of the wave emitted before it arrived and after it passed which will reach you at the same time. Perhaps this interference is the cause of the pulsing nature of the noise?

I refine my set of satellites to just the ones I can be sure are carrying radar instruments. It is a good fit for a lot of the worst peaks but it seems like there are still some missing. I add more groups of satellites. It seems the lesser groups need to be closer to cause the noise. I take the biggest set I can find. I remove all the geostationary satellites as they will never pass by and GPS which are very high altitude with a minuscule signal. I am left with about 900 in my set. It appears that almost any satellite, even the smallest are able to contribute to the hum if they are close enough. I can only explain this if they are all using a radar altimeter.

I start using a another program called Orbitron[82]. This gives a ground-track view as opposed to a view of the sky above. It is more useful for my observations and can deal with a lot more satellites. In addition it has a prediction function who's usefulness did not dawn on me for a while. I was still keeping logs and then winding back the software to find out what the causes were. Then I realised the time of maximum elevation that the prediction yielded was exactly the time of closest approach. I set to work programming. I re-process the output from Orbitron to give me all that come within a certain distance. I build in an arbitrary decay for the sound level and before long I am looking at a graph which is my forecast for the hum. I refine the software and refine the set of satellites and I spend what seems like æons just listening to the hum and watching the screen. The peaks are there but they are not a perfect fit, the troughs are really obvious though.

It is now clear that the frequency of satellites passing by is pretty much the same at any given time. So why then are some times worse than others? I have a forecast for the hum, but not the atmospheric conditions. I read up on transmission of sound in the atmosphere[21]. It depends heavily on the temperature and moisture of the air. Very low frequencies encounter very little resistance and can actually travel thousands of kilometres. I am already aware they can carry over 300km. Variation in wind speed with altitude creates layers and causes a ducting effect, which helps transmission. Probably most significant of all is the occurrence of a night-time inversion[22]. At night the cooling ground cools the air from below creating a temperature gradient which causes sound to be directed back down to the ground. In the day-time it curves up and away from the surface. This would account for it generally being much louder at night.

Going back to my pencil and paper I eventually manage to work out how to calculate the phase difference of a wave from the approaching satellite and a wave from the departing satellite. This only makes sense if you know the wavelength of the sound, I do not. As I am thinking about this problem it occurs to me that this must be how sonic booms work as well. I had never really thought about it before but a sonic boom is not a momentary event as the sound barrier is broken but a continuous pressure wave which follows the super-sonic object. A visit to Wikipedia confirms this for me and puts a name to it - the boom carpet[15].

Just out of interest I plot the timing of would-be booms onto the same graph using a simple formula for the speed of sound. This is it!. Time after time where a boom is plotted I get a sudden increase in hum. With some I actually hear a classic double "ba-boom". So that's it! I don't need the problematic explanation of photon density. I've just been able to cancel all the infinities out of the equation. It would seem the reason the hum is so annoying is because there is so much of this junk up there and it is the boom carpets interacting which create this infernal din. A lot of it literally is junk as well, some of the biggest objects whizzing around are rocket bodies, discarded after delivering their payload. There is a load of defunct cold-war era stuff. There is one still up there that was launched in 1958. Add to that the debris from a collision in 2009 and a Chinese satellite used as target practice in 2007 and you are looking at over 60,000 objects (of track-able size).

Everything you read will tell you that there is no transmission of sound above 160km[53]. I have heard astronauts tell of not being able to hear a hammer blow while working on the outside of the ISS. The explanation for this is that the molecules are so far apart they rarely meet[53]. They are, however, numerous enough to cause drag on satellites, so there must be some sort of interaction going on and I would expect it to be significant for an object travelling 22 times the speed of sound, weighing several tonnes and having a non-aerodynamic shape. The description of the anacoustic zone does say, though, that low frequency propagates for longer and furthermore a sonic boom is a shock wave which is somewhat different in nature to a normal acoustic wave. Supersonic flight was severely restricted by many countries, following tests in the USA. The annoyance factor was given less consideration than the damage to property but laws were passed. Concorde was never allowed to go super-sonic over land. The US military now needs special permission for test flights and the British military are banned from causing one over land or near shipping lanes. The Space Shuttle (STS 134) woke everybody in Florida up on it's way home at 2:30am EDT[54]. Now I know why this was covered up!

Now my understanding has changed I decide to rewrite the software. I start from scratch optimising everything as I go. This time I properly model the layers of the atmosphere and the average speed of sound in each. The speed of sound is mostly dependent on the temperature of the air. The temperature of the thermosphere is highly variable with day and night, the seasons and solar activity so I include a slider to adjust for this in the interface. I am even able include size data for most, deriving it from radar cross-section and magnitude data. I am under threat of eviction but that does not feature in my thoughts; I know I'm on to something and apply myself obsessively to the task. This time I use QuickSat to automate the satellite prediction it's buggy and awkward to parse the results but infinitely quicker than Orbitron. I estimate it will take me a week. It takes me a week.

It's done! I run the prediction and load the data into the chart. I sit back and listen. There are roadworks and landscaping going on in the vicinity making for intense concentration to discern the hum. But it's there all right. "Ba-boom, boom, boom, ba-boom, boom, ba-boom". Close approaches are very obvious indeed and very accurately plotted on the graph. I play with the slider to bring the plots of more distant satellites into line. The average speed of sound in the thermosphere is coming out around 512-515 metres per second. I sit and watch and listen for hours on end. I have bouts of tinnitus from concentrating on the sound for so long.

It's not perfect but it seems to be pretty close to what I'm hearing. Data for some satellites is classified and is estimated from amateur observations. No doubt there are some that "nobody" knows about but there are easily enough to prove the point. This is what I hoped for all along. I know I can prove this to anyone now. I could sit behind the screen while somebody else watches and indicate to them all the significant events to within a matter of seconds. It is literally that accurate; it's better than I hoped for. I sit and watch and listen. I begin to notice something else; Some have their own particular sound, the rocket bodies kind of go 'whump' and the Iridiums, which are oriented vertically giving them a very short length relative to their path, have a very crisp and accented 'da-da'. The rest of the noise seems like an echo of these booms; a delay as the sound reaches you by different paths.

The Software[download]

There are three parts to the application: Humdata is used to produce the data set for the forecast, Humcast is used to visualise the prediction of sonic boom times and intensity and Humhear is used to record what a hearer experiences and creates a data set that can be fed back to Humcast to compare the experience to the prediction.

Humdata uses Mike McCants' Quicksat[83] program to predict satellite passes. This requires up-to-date Keplarian element sets (TLE's) as input. Since satellites experience atmospheric drag and other perturbations due to gravity and solar wind they need to be constantly updated. Within the element set is a value that represents the error and this will increase the older the set is. This is represented in humcast by an error value in seconds. Events with an error greater than 10 seconds will be shown in green. When the graph starts to show a lot of green it is time to update the elements. This is a simple matter of clicking the <On Your Marks> button which will fetch an updated set of elements from the internet. The <Get Set> button needs to be clicked each time the program is run. It creates the initial set of satellites and filters it by removing geostationary and anything smaller than a certain size (defined in humdata.ini). Size information is gleaned from radar cross-section and magnitude information, those for which it can not be determined will be shown in red and orange. The element sets need to be updated approximately once a week. The <Go> button will run the prediction through Quicksat and format the data for Humcast. There are four essential parameters that need to be set for Quicksat: Your location, defined as degrees North (latitude) and West (longitude), note that longitude is conventionally defined as degrees East; Your time zone relative to GMT, remembering to adjust for daylight saving; Lastly the date of the prediction, which will default to the current date. Note that should you require data for the past accuracy will depend on having the TLE files contemporary with that date (this will require keeping a copy of each downloaded set).

Humcast shows you a graphical representation of predicted times of sonic booms from the satellites passes calculated with Humdata. The value of each datum is based on the size and range of each satellite, both of which will affect the volume. The timing of the event is dependent on the range and the speed of sound through the various layers of the atmosphere. It is, in fact, far from perfect. There are many unknowns involved and I have had to make some gross approximations. The slider adjusts for the speed of sound in the thermosphere only (this is the most significant variation), obviously the temperature of the other atmospheric layers changes depend on many factors and also affects the speed of sound. Because the temperature of the thermosphere swings wildly day and night it means that in the morning sound from the east will arrive sooner and in the evening later. The software could compensate for this, though I'm not sure how to calculate it, it will take lots of observation and a fudge factor. However, if you are able to spot some of the more significant events then it should be possible to adjust the value so that these events can be aligned to the predicted values. Once settled upon you should then be able to discern some more detail in the data. You may zoom in to reveal more resolution by dragging the mouse over a section, right-clicking and selecting <Zoom In> from the menu. <Zoom Out> will take you back to the view of the entire day. As each event is reached the list will automatically scroll and highlight that event. You may click the graph at any point to highlight the list item for the nearest point in time or search the list for any particular text string by entering it in the box beside the <Search> button and clicking the button. Either of these actions will stop the automatic scroll of the list, right-click the button (which will have changed to <Next>) to resume automatic scrolling.

In order to collect truly impartial data I decided I needed another program to simply record what I was hearing and see if it matched the prediction. This is the purpose of Humhear. To have any chance of matching experience to prediction at least an hours worth of data is required. This is easier said than done. It requires a building with a propensity for hum (all do, but some are worse which is better in this case), a quiet location or time of day and a minimum of interruption. Moreover, the listener, besides having a good ear requires incredible amounts of patience and concentration. When you couple that to the hum's ability to wreck concentration, you have quite a battle on your hands. On the occasions I have tried this I have found myself drifting off, thinking about something else, then missing the events I was supposed to be recording. There are two inputs to Humhear, peak and background. Peak values represent when a boom is heard. This takes practice listening because there are booms all the time which are echoes of the original. You have to study the nature of the sound; besides the slight exaggeration of the initial boom over its echoes you will need to recognise the slight change in the quality of the sound as each new source is introduced. I suspect very few people will be capable of this, I hope I am wrong. I have found background somewhat easier to record. It is very good at showing up quiet spells. You may record one or both together.

There are still some essential improvements needed to improve accuracy (always assuming TLE's will continue be available and accurate). The speed of sound in the lower atmosphere needs to be taken into account (this can be tweaked in humcast.ini) as does the daily shift in temperature and the direction of the approaching satellite. I think mid-winter and mid-summer are possibly out of range with default values. Although it will be nice to get the icing on the cake I don't think it is absolutely necessary to have Humhear feedback to appreciate the validity of this theory. There are times when, no matter how you are distracting yourself from the constant background grind, it will come rumbling through - Run Humcast, if you see a large peak right about that time, or perhaps a tight conglomeration of events, then you will come to realise that this is, in fact, what is causing "The Hum".

The Rest

This is not about having a rest after completing my quest, rest has become something of an impossibility these days anyway. No, this is about the rest of the picture and the rest of the people who are not yet convinced. As for those who try to discredit me; they will only be doing so because they have been paid to by a vested interest, the rest of that particular story will have to wait for another day.

For some this will already make sense. It explains why it's global, why it started when it did and why it is becoming more prevalent (on average there is one satellite a week being added to the mix). It explains the nature of the noise, its incredibly low frequency and why it is louder at certain times. It can explain why the information was classified and why there is no public knowledge on the subject. When I found a graph of the altitude variation of the ISS[44] it explained why it had stood out so prominently at that time and possibly why the Windsor Hum group got started in April 2011. This is also the time residents of Beaufort, Co. Kerry became aware of it.

If the annoyance of this noise is only related to the level at which a person hears it then fair enough; All I have achieved is to stop a million people from wondering what it is and then being duped when they search for answers. At the same time I hope the medical profession will accept that this an environmental problem, that it is having a serious and debilitating effect on some people and that it may constitute a wider health risk. At the moment all symptoms related to this pollution are being classed as tinnitus or non-specific depression and sufferers get labelled malingerers or, worse still, psychotic. This is absolutely ridiculous, unacceptable and demeaning. This is my main reason for writing this paper.

Sleep problems have risen steeply in recent years and seem to be a consequence of the modern world in some way. Technology and lifestyle are being blamed for this but can not account for it. Surely if you work hard you should sleep well. When did sleep start to become such of a problem, it should be the easiest thing in the world. 'How to sleep' came sixth in Google's most popular how-to searches or 2011[38]. Something is seriously wrong. (There is something wrong with the people who searched for 'how to kiss' as well, perhaps it is related?) If you are unable to sleep many things pass through your mind. In trying to find a reason for your insomnia you may be blaming the things which cross your mind during these times unaware that it is the physical environment that it is making you uneasy and fearful and it is your emotional state initiating those thoughts.

I urge someone to find out if infrasonic noise disturbs sleep patterns and physiology and also if the waking state is affected, the trouble is there is no silence to compare it against any more. The effects of infrasound have never been properly researched or if they have the results were never published. In general it is considered a nuisance, then again it can be therapeutic, at worst the effects are horrifying[36]. If these things turn out to be true (there is no polite way of saying it) we are all in deep sh1t and have been for some time without even realising it. If you are still having trouble accepting that there are subconcious effects from infrasound just look at all the reports of people trying to track down the source. You literally can not stop yourself from wanting to know where it is coming from and everybody that hears it is driven to do the same things.

Low-earth orbit is not what I call space. You could comfortably drive to the space station and back in a day if your car could travel vertically. Rockets are big but they are not clever, orbital mechanics is simply an extension of ballistics. Putting a satellite into orbit is rocket science but it is not, except for a few exceptions, doing anything to advance science in general. NASA defines the edge of space as 100km, this is known as the Kármán Line[18], it is the limit of aerodynamic flight, not the edge of the atmosphere. The atmosphere does not even have an edge, you can find helium and hydrogen anywhere in the space between the planets. It does not matter what you decide to call the edge of space there is still nitrogen and oxygen in the thermosphere, where these things orbit, and the atmosphere is dense enough to cause drag.

There may be no transmission of audible acoustic waves in the upper atmosphere but a sonic boom is a shock wave, it has a huge amplitude and very low frequency. Initially a shock wave can travel faster than the speed of sound until it decays into an ordinary sound wave. Incredibly there are pressure waves that can even cross interstellar space. So to say that sound just ceases to transmit at a certain altitude is an oversimplification to say the least[16]. A sonic boom is sometimes known as the N wave; a sudden compression followed by a rapid decompression and it is over. However since there are several (many) different layers of atmosphere for it to travel through a multitude of echoes are created as the sound is bounced around, even in the thermosphere[17][43]. The Hum is the result of these booms and echoes from well over a hundred satellites an hour which come within earshot (roughly a hemisphere of 2000km radius over your head).

The transmission of sound in the atmosphere is dependent on many variables and this accounts for the difference in the level of noise on a daily and seasonal basis. It is not just the weather since "weather" only occurs in the troposphere, it is also the conditions in the upper atmosphere which need to be taken into account as well. Differences in the temperature of these layers and the wind speed in each will all affect the transmission of sound. Weather patterns can be linked to variations in the hum. Usually high pressure will reduce the effect. It brings stable conditions which allow the air to be warmed by the sun creating an acoustic shadow. In winter, though, high pressure can cause frosty nights; this cools the air near the ground and can create an inversion which will last all day if conditions are right. The summer months (if you can call them that any more) never seem quite as bad. Thick layers of cloud and high humidity will probably make matters worse, though.

Certain people will insist you must have a recording or measurement of the noise; some material scientific proof of its existence. There are a number of problems with this: Almost all audio equipment has a frequency response that has been designed around the accepted human hearing response curve, it would be expensive and pointless to do otherwise. Even if you are privileged enough to use a noise level meter with sufficiently expensive electronics you will then be presented with a Fast Fourier Transform (FFT) view of the data. The Hum does not really have a fundamental frequency as such, it is a discontinuous noise made up of irregular pulses, I'd call it brown infrasound, Wikipedia calls it iso-sumthinorother[ref. req.]. I'm no expert but I thought FFT's needed to find fundamentals? Furthermore it doesn't matter how good your recording equipment is, if you do manage to record it, because you are pushing the envelope, there will be a lot of noise and that noise will worsen when you reproduce it, if you filter it at any point you will lose quality - the non-hearers won't know what they are listening for, even the hummers will have trouble making it out. The best way to demonstrate to a non-hearer is to synthesize the sound, but try not to break your speakers!

The ear and the brain's ability to detect and filter sounds still surpasses any electronics that exist. It does not do any good to go chasing after this noise with a microphone. You might have more luck with a seismometer, though seismology is concerned mainly with under 10Hz so, again, would it work? At the end of the day, even if you do get a good recording or measurement it will still not convey to another the full unpleasantness of this sound. Its annoyance factor lies in the nature of the sound and in its persistence. Worse still is its global presence, there is no escape, absolutely none. You can only really understand its effect from the testimony of a sufferer.

Einstein once said "It is easier to split an atom than it is to break a prejudice". How true this is. There are two deeply ingrained prejudices which are preventing people accepting the propositions I am presenting here. Firstly that satellites orbit in the vacuum of space and secondly that people who believe that satellites affect their lives in some way are completely nuts. Compounding this is the tendancy for peoples egos to reject any suggestion that you are able to perceive something they are not. These prejudices have been proliferated by NASA with their assertion that the edge of space is at 100km altitude and "other government organisations" with their derision of the Bristol Hum sufferers by suggesting it was an electro-magnetic effect and perhaps they should try wearing a tin-foil hat. There are many other ways that this information is being kept from the public and, since it concerns the very tools of their trade, military intelligence are keen to keep it that way. They have been manufacturing myths, controlling information, and influencing opinion for over 40 years, initially as cover for their (illegal) surveillance operations but also now to support a burgeoning economy. The sad truth is that they are doing so in the full knowledge that a section of society is suffering and when sufferers try to get help they are mocked in the most denigrating way.

References:

Reports

[1] Wikipedia

[Web] The Hum.

[2] The Bristol Hum

[Web] BBC News - Have you heard the 'Hum'?

[Web] BBC Bristol - The Bristol Hum: your viewpoints.

[3] The Taos Hum

Web Taos Hum Homepage.

[Web] Ellie Crystal - The Taos Hum.

[4] The Auckland Hum

[Web] Sydney Morning Herald - Mystery humming sound captured.

[Web] Dr. Tom Moir's personal website.

[5] The Woodland Hum

[Web] The Telegraph - Tiny village is latest victim of the 'The Hum'.

[Web] Teesdale Mercury - 'The Hum' puts small village in the national spotlight.

[6] The Swanage Hum

[Web] Bournemouth Echo - Hum-thing in the air?

[7] The Bondi Hum

[Web] The Daily Telegraph (Australia) - Bondi's mystery noise maker.

[8] The Largs Hum

[Wb] The Guardian - What's that noise?

[9] The Kokomo Hum

[Web] New York Times - Hum Haunts Indiana City.

[10] The Beaufort Hum

Irish Examiner - The Hum Leaves Villiage Ears Ringing

Physics

[13] Optical Tweezers

[Web] Wikipedia - Optical Tweezers.

[14] Photon Density

[Web] Bill Bruno - What does photon energy tell us about cellphone safety.

[15] Sonic Boom.

Wikipedia - Sonic Boom.

[16] Sound in Space

Yoo Chul Chung - Sound in Space.

Cornell University - Curious About Astronomy.

[17] Sonic Booms in the Thermosphere

Acoustical Society of America - Propagation of sonic booms in the thermosphere.

[18] The Kármán Line

Wikipedia - The Kármán Line

[19] Dr Chris Barnes, PhD

Collection of Works and Comments on The Hum.

Weather

[21] Transmission of Sound in the Atmosphere

[Web] Engineering Acoustics - Outdoor Sound Propagation.

[Web] CSGNetwork - Sound Absorption Calculator.

Wikipedia - Sound Speed Gradient.

[22] Temperature Inversion

[Web] Wikipedia - Inversion (Meteorology).

[Web] Answers.com - Atmospheric Acoustics.

Biology

[31] Brainwaves

[Web] Wikipedia - Electroencephalography.

[32] Entrainment

[Web] Wikipedia - Brainwave Entrainment.

[33] Sense of Hearing

[Web] Wikipedia - Sense of Hearing.

[Web] Wikipedia - Threshold of Hearing.

[34] Diabetes

[Web] The Cleveland Clinic Foundation - Does lack of sleep cause diabetes?

[Web] The Daily Mail - Diabetes risk 'soars with lack of sleep'.

[35] Behavioural Problems

[Web] NHS - The Link Between Poor Sleep and ADHD.

[Web] NYTimes - School Bullies Prone to Sleep Problems.

[36] Physiological and Psychological Effects

[Web] Sonic Weapons.

[Web] Possible Effects of Infrasound.

[Web] Sick Building Syndrome.

[37] Infrasound

[Web] Answers.com - Infrasound.

[Web] Wikipedia - Infrasound.

[38] Sleep Problems

Google Zeitgeist 2011 - How to ...

[39] Suicide

John Dawes - Extracts from British Newspapers.

Satellites

[41] Cloudsat

[Web] R. Keith Raney - Space Based Radar.

[42] Sonic Boom

[Web] Orlando Sentinel - Space Shuttle (STS-134) Returns.

[43] Columbia Disaster

[Web] SMU - Infrasound Analysis of Columbia Disaster.

[44] Altitude of ISS

[Web] Heavens Above - Altitude of ISS.

[45] Space Junk

Fox News - Catastrophic Satellite Collision.

Space Mart - Destroyed Chinese Satellite Threatens ISS.

Secrecy

[51] Microwave Hearing

[Web] Clyde E. Ingalls - Sensation of Hearing in Electromagnetic Fields.

[Web] Wikipedia - Microwave Auditory Effect.

[52] Speed of Sound

[Web] Aerospaceweb - Mach vs. Altitude.

[53] The Anacoustic Zone

[Web] David Darling - The Anacoustic Zone.

Forums and Message Boards

[Web] [61] Mast Victims - Evidence for Microwave Hearing.

[Web] [62] Yahoo Hum Forum.

[Web] [63] Google Groups - Hum Sufferers.

[Web] [64] Facebook - Windsor/Essex Hum.

Sounds (Good quality audio equipment and/or headphones essential)

[Web] [71] Moir - Auckland Hum.

[Web] [72] Moorhouse - Salford Hum.

[Web] [73] Beaty - Taos Hum.

[Web] [74] Theroux - California.

Software

[81] Stellarium

[82] Orbitron