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The last update: December 6, 2003
Here is some info on a problem of electrophonic sounds, i.e.
sounds simultaneous with a bright bolide passage.
My letter published in the November, 1998 issue of METEORITE! magazine, and
the follow-up debates with C. Keay in the February 1999 issue;
My letter published in the Feb.3, 2001 issue of NEW SCIENTIST
magazine;
My abstract for METEOROIDS 2001 conference;
Interesting account on probable electrophonic sound associated with a
missile launch;
This fabulous World...;
Electrophonic sounds have been confirmed?!
Sir,
I would like to comment Colin Keay's theory on electrophonic sounds (Meteorite!, August '98). At first, Keay's idea means that a bolide producing electrophonic sounds is to generate in its wake VLF radiation with the power at least about 10^12 W (Wang, D.Y., et al. J. Roy. Astron. Soc. Can. v.78, no.4, p.145 (1984)). As far as I know, no present theory either experiments with turbulent ionized wakes or predicts such superpowerful VLF radiation. Anyway, if it is realized somehow, it leads to spectacular effects, for example, to enormous Joule heating of the wake (due to extremely large electric currents) transforming the wake into object as bright (seen from the ground) as at least the Sun (see: Ol'khovatov, A.Yu. Geomagnetism and Aeronomy. English ed., v.33, no.2, p.264 (1993)). And, of course, this "super-radiation" would produce remarkable global effects - but none of them are known.
Moreover, the "electrophonic" bolides look like "ordinary" bolides - no signs of superpowerful electric currents in their wake (for example, see published in the Keay article the photo of the Peekskill fireball).
By the way, in many electrophonic events the power of aerobraking, i.e. the power deposited by a meteoroid into the atmosphere, which is to be the energy source of the proposed VLF radiation was much less that the power of the latter.
For example, on p.108 of December 1993 Sky & Telescope there is a photo of a "hissing" fireball of April 15, 1993, which became visible at a height of about 98 km and disappeared at 75 km after a flash with magnitude -9.5. Its looked like an "ordinary" bolide - no hints on the "superpowerful radiation" from it (I don't even touch here that it was too high for the existence of a "turbulent wake").
But the best example is the Space Shuttle re-entry, accompanied with electrophonic sounds. At that time the Shuttle was about 60-70 km high with a speed about 5-6 km/s (seen from the ground as an object with magnitude -1 to -2). Its aerobraking power was about 10^10 W. Moreover in its photo fortunately taken about the same time (see Aviation Week & Space Technology v.122, no. 3, p.85 (1985)) again there is no evidence of the "super-radiation".
I'd like also to add that, of course, some weak plasma instabilities in the wake under the action of ionospheric factors etc. can take place, anyway they are negligible compared with the "super-radiation".
Electrophonic phenomena have been observed in cases when it is known reliably that intense VLF radiation from the fireball wake did not occur. And I could add that if it takes place during the Shuttle re-entry, it would produce a devastating effect on its avionics and possibly even the crew and its fuselage!
By the way, Keay's remark that "the reports [on the Space Shuttle electrophonic sounds] ceased", also hints that the physical agent of the sounds was not produced by the Space Shuttle wakes, but more probably just was triggered by the flights in certain geophysical circumstances (see for details: Ol'khovatov A.Yu. Izvestiya [Russ. Acad. Sci.], Physics of the Solid Earth. English edition, v.29, no. 12, p.1043 (1993) and Priroda, no. 5, p.68 (1995) (in Russian)).
Andrei Ol'khovatov
Moscow, Russia
A. Ol'Khovatov (Letters, Meteorite!, November '98) asserts that bolides
must generate "superpowerful radiation" for electrophonic sounds to be
heard by witnesses on the ground. This is not a requirement of my theory
for the production of electrophonic sounds from large bolides.
Ol'Khovatov bases his
claim of terawatt source power on figures published by Wang, et al..
(JRASC, 78, 4, 145-150, 1984) on the basis of electric field strengths
of 160 V/m measured in my laboratory tests of direct human sensitivity
without transduction by external artifacts (JRASC, 74, 5, 253-260,
1980). These fields happen to be in complete accord with earlier work by
Ivanov and Medvedev (Geomag. and Aeronomy, 5, 216-219, 1965) who showed
that comparable induced field variations could result from some bolides
in appropriate trajectories when the Earth's geoelectric field is higher
than usual. On the question of power levels, however, I consider as much
more realistic Vitaly Bronsten's calculation (Solar Sys. Res., 17, 70-4,
1983) of megawatt source power based on my theory for the generation of
the kilohertz radio emissions which give rise to observers hearing
sustained electrophonic sounds.
On the question of energy requirements, it may be worth noting that in
the early days of radio broadcasting, stations with a radiating power of
only a kilowatt at distances of hundreds of kilometers could be received
by unpowered crystal sets! Given an appropriate transducer the human ear
is able to detect extremely low levels of power under quiet conditions.
Returning to the problem of electrophonic sounds from bolides, it is
becoming apparent that there are many mechanisms by which ELF/VLF energy
may be transmitted instantly to an observer, depending on the situation.
Electromagnetic energy may be produced by explosive disruptions of a
bolide (similar to the transient EM pulses from a nuclear air-blast), or
by my mechanism (Science, 210, 11-15, 1980). Also there are purely
electrostatic mechanisms such as that of Ivanov and Medvedev or simply
the action of a zenithal meteor entering on a steep trajectory to
produce a conductive path below the ionosphere which creates a strong
transient in the geoelectric field at the surface of the Earth. This
latter effect could explain the recent aural observations of Leonid
fireballs by K Matsuura in Japan (private communication).
Clearly, much further study is needed to clarify outstanding problems of
geophysical electrophonics.
Colin Keay
Physics Dept.
University of Newcastle
NSW, Australia
Ol'Khovatov replies...
In response to my criticism of C. Keay's theory about the origin of the
electrophonic sounds, C. Keay states that just a megawatt power source
of VLF/ELF radiation from a bolide's wake is enough to produce
electrophonic sounds. But I can't accept his arguments.
The terawatt power source estimation is based on applying well-known
formulas of electromagnetic radiation to Keay's idea. So to go down from
"terawatts" to the "megawatts", C. Keay must find a mistake in Wang D.
et al.'s calculations or change something in his theory. These are not
done.
V. Bronsten was just trying to calculate the magnetic energy that could
be stored in a bolide's wake according to the Keay theory and he got the
energy relaxation rate estimation of "gigawatts". Then he speculated
that about 0.001 of the energy could be transformed into radio waves. In
other words, if his result is correct, it just imposes an upper limit on
the power of the hypothesized radio waves - on the order of megawatts.
As we just saw, it is a million times less than needed to produce the
required 160 V/m electric field strength on the ground.
By the way, if the Keay "megawatt" estimation (which completely
contradicts his 160 V/m value) is correct, that means that residents
dozens of miles away from VLF/ELF radio stations (many of them have
about such power) must hear the electrophonic sounds around the clock!
And what about the radio station's personnel?
In my previous Letter, I also have mentioned several other evidences
against the Keay idea. Even the shift from "terawatts" to "megawatts" is
not able to avoid the majority of them. For example, even "megawatt"
power can produce remarkable effects on Space Shuttle avionics. And, as
I have written, the electrophonic sounds were heard when a rather weak
bolide was too high for the existence of a turbulent wake. I hope that
C. Keay will consider these aspects too, if he insists on his theory.
Andrei Ol'khovatov,
Moscow, Russia
In reply...
Ol'Khovatov still does not realize that detection of electrophonic sounds from fireballs relies on the presence close to the observer of a suitable transducer of adequate efficiency (hence my crystal set analogy). That is why observations of such sounds are rare and quite capricious. Time will tell who is correct. Right now an explanation for the phenomenon better than mine has yet to emerge. My explanation has thus far met most criticisms except those based on misinterpreted data."
Colin Keay
Editor's note: 1 megawatt = 1 million (10^6) watts, 1 gigawatt = 1 billion (10^9) watts, 1 terawatt = 1 trillion watts (10^12) watts. Further research involving the Space Shuttle to resolve this matter is being planned. Stay tuned.
And here is from the Feb.3, 2001 issue of NEW SCIENTIST magazine:
I read with interest Harriet Williams's article on various theories for the "electrophonic" sounds heard while watching auroras or meteors ( 6 January, p 14), the most serious problem with the theories is that the power of very low frequency (VLF) radio waves created by meteors is negligible compared with that needed to create audible sounds.
For example, lab experiments have shown that the sounds are inaudible when the power of the VLF waves drops below 160 volts per metre. This means that a meteor producing electrophonic sounds must, according to D. Y. Wang, generate at least 10^12 watts of VLF radiation (The Journal of the Royal Astronomical Society of Canada, vol 78, p 145). As far as I know, no current theory or experiments with turbulent ionised wakes predict such super-powerful VLF emissions.
If meteors could create this power, it would lead to spectacular effects: the enormous heating of the wake caused by extremely large electric currents would transform it into an object as bright as the Sun (Geomagnetism and Aeronomy, vol 33, p 264). So the nature of electrophonic sounds remains an enigma.
Andrei Ol'khovatov
Radio Instrument Industry Research Institute, Moscow
Below is my abstract accepted by METEOROIDS 2001 conference (unfortunately I was not able able to attend the conference for delivering the report):
During last years an idea that electrophonic sounds are caused by
VLF electromagnetic radiation from a bolide's wake is promoted again.
The source of the radiation is considered to be "magnetic spagetti
relaxation" in a bolide's wake.
The most serious problem with the theory is that level of detected
VLF disturbances, accompanied a bolide is negligibly small, comparing
with needed for hearing VLF radiation. For example, C. Keay experiments
revealed lower limit of hearing in order of 160 V/m. It means that a
bolide producing electrophonic sounds is to generate in its wake VLF
radiation
with the power at least in order of 10^12 W. Nor present theory neither
experiments with turbulent ionized wakes� predicts such superpowerful
VLF radiation. Anyway, if it is realized somehow, it would lead to
spectacular effects, for example, to enormous Joule heating of the wake
(due
to extremely large electric currents) transforming the wake into object
as
bright (seen from the ground) as at least the Sun.
And, of course, this "super-radiation" would produce remarkable global
effects - but none of them are known.
The presence of "transducers" near an observer can't help the situation,
as the needed level to hear their vibrations are even in order of
magnitude larger, and anyway, it can't be lowered down many orders of
magnitude.
A solid confirmation that these estimations are correct is the fact that
otherwise people would hear numerours VLF transmitters hundreds miles
away! Also there were reports of electrophonic sounds during several
Space Shuttle re-entries. The the hypothetical "super-radiation" (if
exists) would produce a very remarkable (devastating) effect on the
spaceplane.
Also, in many electrophonic events the power of aerobraking,
i.e.the power deposited by a meteoroid into the atmosphere, which is to be
the energy source of the proposed VLF super-radiation was much less that the
power of the latter.
Below is VERY IMPORTANT eyewitness's account of electrophonic sounds
associated with a missile launch. It was not published yet, but
I hope it will be published soon.
Below is a text I found in W. Corliss "Incredible Life" book. According to
it, the original text is from NATURE v.64, p.233 (1901). It demonstrates,
how little we know still...
A curious phenomenon occurred to some volunteers while on outpost duty on the Delagoa Bay Railway in the Transvaal.
For me the second and the third possibilities are the most probable.
It seems that electrophonic sounds reality has been confirmed!
Here is from http://abob.libs.uga.edu/bobk/ccc/cc012302.html
And here is my comment on the post above from
http://abob.libs.uga.edu/bobk/ccc/cc012402.html:
Return to the A. Ol'khovatov Web-site directory:
www.geocities.com/olkhov
The electrophonic sounds were associated with Trident D 2 missile
launches. Its another striking feature is that the eyewitness was several
hundreds km away from the launches.
Here is how the launches are described in the American Meteor
Society's Fireball Sightings Log http://www.amsmeteors.org/fireball/fireball_log.html):
June 25, 2001 ~0115 UTC: A -4 to -9 magnitude, very slow, very
long duration, yellow fireball was viewed to the east as seen from
Florida, Georgia, and South Carolina, as reported by three witnesses. This
fireball left a smoke trail which lasted for up to three minutes, and the
descriptions sound suspiciously like a missile launch (we have since
received confirmation that this event was indeed a military missile launch)
(no. 65).
According to the the Orbital Report News Agency three suborbital
missile Trident 2 were launched from somewhere east of Cape Canaveral from
submarine� USS Louisiana http://www.orbireport.com/Logs/Log01/Log2001-06.html ).
One of the eyewitnesses - a 44 years old woman (she asked not to
mention her name, unless it is strongly needed) reported to internet
METEOROBS Mailing List ( http://www.meteorobs.org ) on August 3, 2001, and
then to the author the following:
She was at the latitude approximately 34 degrees 16' 22.5". The
longitude was 80 degrees 37' 00" (the instersection of these coordinates is
just slightly east and south of the pond she was standing beside when she
saw the fireball). She heard rushing sounds at the time of the sighting:
"The sound I heard was a very soft rushing sound. There was no
breeze at the time. Furthermore the sound was not like the wind blowing.
I've compared it to the sound of a sparkler without any popping noises but
softer. The level was barely audible.
The report is remarkable and very important, as it is well-established that
such missile launches don't produce any appreciable level of VLF/ELF
electromagnetic radiation. The report does not conform with theories that the
powerful radiation from a bolide wake is the source of the sounds. On the
other side, it well conforms with my idea that a bolide is just a trigger
in certain geophysical environment of some still poorly understood geophysical
processes which produce the sounds (possibly directly affecting our mind).
I dismissed them figuring they were imagined because I expected there
should be a sound. It wasn't until I read Pierre Martin's website that I
learned what it was.
When I observed the object, now reported as a missile, I was releasing
a fish I had caught. I was kneeling at the edge of a pond in South Carolina
when my three year old daughter called my attention to it. The sun had set
but the sky was not yet completely dark. The trail of the object was slightly
illuminated by the remaining rays. There were some very high clouds to the
east. I can't remember if the moon had risen. The time was approximately
9:15, Eastern Standard Time (21:15 EDT). The report I filed is posted on the
AMS Website Fireball Log at� http://www.amsmeteors.org/fireball/fireball_log.html
(Item 65-3)
It was a still, humid night. The temperature was pleasant not sweltering
hot - perhaps low 80's. There is only one road nearby which crosses the pond
on the dam. No traffic was on it. There was no one else about. The rest of
the family was in the house.
The house is on a large lot and the neighbors are not close. The pond is
probably a couple of acres in size. The closest structure was a 12 foot by
12 foot wooden dock, perhaps 10 ft (about 3 meters) away from me. It was in
front of me as I observed the object. To my left was a pump for the lawn
irrigation - perhaps 4 meters away. On my right, a little farther away
was a metal fishing boat about 3 meters in length. Pipes run under the
ground for the spinklers. I don't know if the pipe is metal or plastic. The
topography of our area is generally flat. In the immediate area it slopes
gently down from the house to the pond.
I did not immediately hear the sounds when I saw the object but they
followed occuring to my best recollection over the last half of the flight
and ending perhaps shortly before it became obvious that the object had
ceased making a smoke trail. By the time I heard the sound I was standing
holding my daughter's hand. I may have been holding her.
Needless to say, it had my full attention and was an awesome sight. I
do not wear glasses. My hair is cut short, long enough to just cover my ears.
I was not wearing a hat. The sounds were extremely subtle, soft enough to
make me doubt that I had heard them as nothing nearby could supply so soft
a sound.
A psychologist would find this following conclusion suspect since I
have read a few theories about the source of electrophonic sounds the week
following the event. That said, it was as if the source of the sound was
unidentifiable but nearby. It was unlike hearing regular sounds. I remember
trying to determine if I had really heard the sounds but since I didn't have
an immediate source, I dismissed them as a function of my imagination.
However, when I think on it, the rushing sound I heard, is not the one I
think I would have fabricated. I think that a sound of a louder more
conventional type is what the imagination would have supplied."
Interestingly that the eyewitness was near a pond, and it seems that
electrophonic sounds, as well as similar, so called "earthquake sounds"
(often preceding earthquakes) gravitate to water reservoirs (or their
borders) indeed.
Also remarkably, that I wrote in my article Izvestiya [Russ. Acad.
Sci.], Physics of the Solid Earth. English edition, v.29, no. 12, p.1043
(1993)) that a large missile's (especially with a solid-propellant engine)
launch sometime could play the same role as a bolide. And it seems to be
confirmed now. By the way, Trident 2 is a solid-propelled missile....
A Curious Phenomenon
Hutt, Stanley B.
I can just add my question to the Mr Hutt's one (I am afraid that he never got an answer to his question...).
A searchlight was fixed up in the station, which was used nightly
in scanning the wide stretches of veldt. We were on solitary outpost duty
about three miles from the station, and on the still silent nights which
are frequently experienced in the clear atmosphere of the high veldt we
distinctly heard a low "purring" sound as the ray of light of the station
passed over us. As the light approached us one could hear the sound
gradually increasing, being loudest as it switched over us and passing
away into the nothingness of the silent night. We were too far off the station to hear any vibrations from the mechanism of the search-light, and
we all came to the conclusion (being a collection of unscientific men) that the high velocity of the light waves created a sound audible to our ears. On other nights when there was only a slight breeze no noise could be detected.
Can any one of Nature's readers tell me if this is a known physiological effect?
Could it be:
- A sound of a weak acoustical disturbance produced by a moving source
of heat through the air? (I doubt that it was used to be a supersonic, as in the latter it could be hardly used for "search").
- A sound of some insects, etc. in the air reacting on the light?
- Something related with electrophonic sounds?
ELECTROPHONIC METEORS AND METEOR-ATMOSPHERE COUPLING
>From Slaven Garaj
ELECTROPHONIC METEORS AND METEOR-ATMOSPHERE COUPLING
>From Andrei Ol'khovatov