Hervé
17th April 2015, 15:57
A possible and plausible answer to that low, diesel-generator-like humming:
Have you heard 'the hum'? Mystery of Earth's low droning noise could now be solved (http://www.independent.co.uk/environment/nature/have-you-heard-the-hum-mystery-of-earths-low-droning-noise-could-now-be-solved-10182111.html)
http://www.independent.co.uk/incoming/article9775392.ece/alternates/w620/planet-earth-v2.jpg
It was often blamed on phone masts, submarine communications and pipes
Lamiat Sabin (http://www.independent.co.uk/biography/lamiat-sabin-9839061.html) Thursday 16 April 2015
Scientists have confirmed the cause of a strange humming noise (http://www.independent.co.uk/news/uk/this-britain/in-search-of-the-thing-that-goes-hum-in-the-night-2299300.html) that emanates from the Earth and has baffled people for more than forty years – and was even a factor in one reported suicide.
The noise has been talked about worldwide and also made local newspaper headlines in the UK. It is often referred to as a “phenomenon” and “the hum”, usually prefixed with the location of where it is heard.
In Britain, the most famous example was the “Bristol hum” that made the news in the late 1970s. One newspaper asked readers in the city: “Have you heard the Hum?” and at least 800 people said they had – according to the BBC – and some had suffered headaches and nosebleeds from it.
It has been described like “a diesel car idling in the distance” by a BBC interviewee and the maddening sound has driven people stir-crazy in trying to figure it out. Especially when they can only hear it at home and during the night.
People living on the south coast have complained this week of a constant and low-pitched sound for which they have found no cause – as reported by Plymouth Herald (http://www.plymouthherald.co.uk/mystery-hum-Plymouth-residents-complain-strange/story-26343932-detail/story.html).
It has been mistaken for leaking pipes, phone masts, wind farms, low-frequency submarine communications and even mating fish (http://www.independent.co.uk/environment/nature/mysterious-hum-keeping-people-up-all-night-could-be-mating-fish-8900747.html).
“For the first few years I lost sleep, couldn’t concentrate and was unable to do anything. I was constantly in tears, which put a great strain on my husband. It has changed me from an active, creative person to a stifled, angry pessimist,” a woman told The Independent back in 1994 (http://www.independent.co.uk/life-style/whats-that-terrible-noise-all-over-the-country-people-are-plagued-by-a-strange-hum-are-their-ears-playing-up-or-is-it-something-sinister-emma-brooker-investigates-1424317.html).
Doctors blamed patients’ abilities to hear it on tinnitus, until Addenbrooke’s Hospital in Cambridge had confirmed sometime in the 1990s that the cause is external.
http://www.independent.co.uk/incoming/article8906419.ece/alternates/w460/p10submarineGETTY.jpg
Submarines, as well as masts and gas pipes, were blamed for the hum. However, the search for the truth could now be over as researchers claim that microseismic activity from long ocean waves impacting the sea bed is what makes our planet vibrate and produces the droning sound.
The pressure of the waves on the seafloor generates seismic waves that cause the Earth to oscillate, said Fabrice Ardhuin, a senior research scientist at Centre National de la Recherche Scientifique in France.
The continuous waves produce sounds lasting from 13 to 300 seconds. They can be heard by a relatively small proportion of people – who are sensitive to the hums – and also by seismic instruments.
“We have made a big step in explaining this mysterious signal and where it is coming from and what is the mechanism,” Ardhuin said of the study (http://onlinelibrary.wiley.com/doi/10.1002/2014GL062782/abstract?campaign=wlytk-41855.6211458333) published in Geophysical Research Letters, a journal of the American Geophysical Union.
http://www.independent.co.uk/incoming/article9134480.ece/alternates/w460/sea-bed.jpg
Waves impacting the deep sea bed have been found to be the cause. Understanding the ringing could also help researchers gain a better knowledge of the Earth’s structure, he added.
Microseismic waves penetrate through the Earth’s mantle so recording these waves could give scientists a much more detailed picture of what lies beneath.
Discovering fainter seismic signals could also allow scientists to better detect small or faraway earthquakes.
Read more:
In search of the thing that goes hum in the night (http://www.independent.co.uk/news/uk/this-britain/in-search-of-the-thing-that-goes-hum-in-the-night-2299300.html)
Mysterious hum keeping people up all night ‘could be mating fish’ (http://www.independent.co.uk/environment/nature/mysterious-hum-keeping-people-up-all-night-could-be-mating-fish-8900747.html)
What's that terrible noise? (http://www.independent.co.uk/life-style/whats-that-terrible-noise-all-over-the-country-people-are-plagued-by-a-strange-hum-are-their-ears-playing-up-or-is-it-something-sinister-emma-brooker-investigates-1424317.html)
Comments
Ray_of_Light62 (http://www.independent.co.uk/users/SUID_af837138-5fc9-4cba-abcb-354a558661d7) 7 hours ago
Picking up the earth background hum is no easy feat.
Local "normal" earthquakes consists of a vibration in the 1 to 20 Hertz range of frequencies. The vast majority of seismometers are made of a velocity sensor tuned to the above frequency range. An earthquake taking place in a remote region, thousands of kilometers away, is referred to as a "teleseism" and produces a signal well below the 1 Hertz frequency, in the area of 0.1 to 0.01 Hertz. Normally these low frequencies are measured as period, which is the reciprocal of frequency; so 0.1 Hz is equivalent to 10 seconds.
Seismometers should measure the movements of the earth with reference to a point in the space that doesn't move during the earthquake. As such a thing doesn't exist, seismometers of all kind uses the resting inertia of a mass as its reference. In the case of long-period seisms, precise measurements became impossible. The number of tele-seismometers actually active is only an handful, as they are very expensive, bulky and onerous to operate.
Based on this, it is easy to see why the real reason of background hum noise has gone unnoticed until now. The main wave which is the base of the hum noise can be measured with great difficulties, and is well outside the range of human perception and the normal seismic equipment. All we can feel are the "harmonics", which are a secondary set of waves, at higher audible frequency, produced by the ground, the air, and other natural and man-made structures when they are excited by the original, very-low-frequency seismic wave.
------------------------------------------------------
Does that leave ELFs (http://en.wikipedia.org/wiki/Extremely_low_frequency) communications with submarines off the hook? Nope!
Have you heard 'the hum'? Mystery of Earth's low droning noise could now be solved (http://www.independent.co.uk/environment/nature/have-you-heard-the-hum-mystery-of-earths-low-droning-noise-could-now-be-solved-10182111.html)
http://www.independent.co.uk/incoming/article9775392.ece/alternates/w620/planet-earth-v2.jpg
It was often blamed on phone masts, submarine communications and pipes
Lamiat Sabin (http://www.independent.co.uk/biography/lamiat-sabin-9839061.html) Thursday 16 April 2015
Scientists have confirmed the cause of a strange humming noise (http://www.independent.co.uk/news/uk/this-britain/in-search-of-the-thing-that-goes-hum-in-the-night-2299300.html) that emanates from the Earth and has baffled people for more than forty years – and was even a factor in one reported suicide.
The noise has been talked about worldwide and also made local newspaper headlines in the UK. It is often referred to as a “phenomenon” and “the hum”, usually prefixed with the location of where it is heard.
In Britain, the most famous example was the “Bristol hum” that made the news in the late 1970s. One newspaper asked readers in the city: “Have you heard the Hum?” and at least 800 people said they had – according to the BBC – and some had suffered headaches and nosebleeds from it.
It has been described like “a diesel car idling in the distance” by a BBC interviewee and the maddening sound has driven people stir-crazy in trying to figure it out. Especially when they can only hear it at home and during the night.
People living on the south coast have complained this week of a constant and low-pitched sound for which they have found no cause – as reported by Plymouth Herald (http://www.plymouthherald.co.uk/mystery-hum-Plymouth-residents-complain-strange/story-26343932-detail/story.html).
It has been mistaken for leaking pipes, phone masts, wind farms, low-frequency submarine communications and even mating fish (http://www.independent.co.uk/environment/nature/mysterious-hum-keeping-people-up-all-night-could-be-mating-fish-8900747.html).
“For the first few years I lost sleep, couldn’t concentrate and was unable to do anything. I was constantly in tears, which put a great strain on my husband. It has changed me from an active, creative person to a stifled, angry pessimist,” a woman told The Independent back in 1994 (http://www.independent.co.uk/life-style/whats-that-terrible-noise-all-over-the-country-people-are-plagued-by-a-strange-hum-are-their-ears-playing-up-or-is-it-something-sinister-emma-brooker-investigates-1424317.html).
Doctors blamed patients’ abilities to hear it on tinnitus, until Addenbrooke’s Hospital in Cambridge had confirmed sometime in the 1990s that the cause is external.
http://www.independent.co.uk/incoming/article8906419.ece/alternates/w460/p10submarineGETTY.jpg
Submarines, as well as masts and gas pipes, were blamed for the hum. However, the search for the truth could now be over as researchers claim that microseismic activity from long ocean waves impacting the sea bed is what makes our planet vibrate and produces the droning sound.
The pressure of the waves on the seafloor generates seismic waves that cause the Earth to oscillate, said Fabrice Ardhuin, a senior research scientist at Centre National de la Recherche Scientifique in France.
The continuous waves produce sounds lasting from 13 to 300 seconds. They can be heard by a relatively small proportion of people – who are sensitive to the hums – and also by seismic instruments.
“We have made a big step in explaining this mysterious signal and where it is coming from and what is the mechanism,” Ardhuin said of the study (http://onlinelibrary.wiley.com/doi/10.1002/2014GL062782/abstract?campaign=wlytk-41855.6211458333) published in Geophysical Research Letters, a journal of the American Geophysical Union.
http://www.independent.co.uk/incoming/article9134480.ece/alternates/w460/sea-bed.jpg
Waves impacting the deep sea bed have been found to be the cause. Understanding the ringing could also help researchers gain a better knowledge of the Earth’s structure, he added.
Microseismic waves penetrate through the Earth’s mantle so recording these waves could give scientists a much more detailed picture of what lies beneath.
Discovering fainter seismic signals could also allow scientists to better detect small or faraway earthquakes.
Read more:
In search of the thing that goes hum in the night (http://www.independent.co.uk/news/uk/this-britain/in-search-of-the-thing-that-goes-hum-in-the-night-2299300.html)
Mysterious hum keeping people up all night ‘could be mating fish’ (http://www.independent.co.uk/environment/nature/mysterious-hum-keeping-people-up-all-night-could-be-mating-fish-8900747.html)
What's that terrible noise? (http://www.independent.co.uk/life-style/whats-that-terrible-noise-all-over-the-country-people-are-plagued-by-a-strange-hum-are-their-ears-playing-up-or-is-it-something-sinister-emma-brooker-investigates-1424317.html)
Comments
Ray_of_Light62 (http://www.independent.co.uk/users/SUID_af837138-5fc9-4cba-abcb-354a558661d7) 7 hours ago
Picking up the earth background hum is no easy feat.
Local "normal" earthquakes consists of a vibration in the 1 to 20 Hertz range of frequencies. The vast majority of seismometers are made of a velocity sensor tuned to the above frequency range. An earthquake taking place in a remote region, thousands of kilometers away, is referred to as a "teleseism" and produces a signal well below the 1 Hertz frequency, in the area of 0.1 to 0.01 Hertz. Normally these low frequencies are measured as period, which is the reciprocal of frequency; so 0.1 Hz is equivalent to 10 seconds.
Seismometers should measure the movements of the earth with reference to a point in the space that doesn't move during the earthquake. As such a thing doesn't exist, seismometers of all kind uses the resting inertia of a mass as its reference. In the case of long-period seisms, precise measurements became impossible. The number of tele-seismometers actually active is only an handful, as they are very expensive, bulky and onerous to operate.
Based on this, it is easy to see why the real reason of background hum noise has gone unnoticed until now. The main wave which is the base of the hum noise can be measured with great difficulties, and is well outside the range of human perception and the normal seismic equipment. All we can feel are the "harmonics", which are a secondary set of waves, at higher audible frequency, produced by the ground, the air, and other natural and man-made structures when they are excited by the original, very-low-frequency seismic wave.
------------------------------------------------------
Does that leave ELFs (http://en.wikipedia.org/wiki/Extremely_low_frequency) communications with submarines off the hook? Nope!