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(meteorobs) Iridium satellites' re-entry [Electrophonic Observations]
------- Forwarded Message
Date: Mon, 20 Mar 2000 17:36:52 -0500 (EST)
From: Dejan Vinkovic <dejan@ccsdot ukydot edu>
To: chuck@lunarcolony.com
cc: meteorobs@jovian.com, imo-news@egroups.com
Subject: Iridium satellites' re-entry
Dear Mr. Bonner,
The measurement of the VLF radio waves during the Iridium satellites'
re-entry is an interesting idea and my colleagues will try to do that if
the re-entry happens over Europe.
During the 1998 Leonid storm we managed to detect some VLF emission from
the Leonid fireballs over Mongolia. Also, we recorded the
anomalous (electrophonic) sound from two fireballs, but the sounds were not
accompanied by the VLF signal (the receivers were able to detect
frequencies between 500Hz and 10kHz). Both sounds can be described as a
"pop" and they cover frequencies below 200Hz. This is an indication that
the radio waves below 500Hz had probably produced these sounds.
The phenomenon of anomalous meteor sounds really requires (and deserves!)
more study. The existing theory of ELF/VLF emission from meteors can not
explain our measurements. The sounds were created when the fireballs had an
altitude of 100-120km, where the condition of turbulent wake with frozen
magnetic field was not possible.
Also, many witness reports of electrophonic sound suggest that the existing
theory needs a refinement. This was motivation for introducing the Global
Electrophonic Fireball Survey (GEFS) at University of Kentucky:
http://gefs.ccsdot ukydot edu
Since we know so little about the electrophonic sounds, the witness
reports, even the most simple ones, are very valuable. GEFS is one attempt
to collect them.
I agree with you that we should put more attention to the re-entries of the
Iridium satellites. The meteor observers should be aware of a possibility that
these re-entries will produce the electrophonic sound.
> I have read very little about this electroacoustic effect (apparently,
> little information is available), but I have heard a fireball myself once.
You have a very interesting "electrophonic experience". Can you send me
a detailed description of the event, please? At the end of this e-mail, I
have attached the GEFS form, available also at:
http://gefs.ccsdot ukydot edu/GEFS_Form.html
It would be very interesting if you can recall all possible details which
can be, (or you think they are), related to the meteor.
Sincerely,
Dejan Vinkovic
Department of Physics and Astronomy
University of Kentucky
Lexington, KY 40506-0055
dejan@padot ukydot edu
- -----------------------------------------------------------------------------
- -----------------------------------------------------------------------------
- -----------------------------------------------------------------------------
Global Electrophonic Fireball Survey (GEFS)
Data Submission Form
It is not necessary to fill out the form completely. Just provide as much
information as you can remember or have available.
If you are not sure in the exactness of your data, skip it or mention this
as a comment at the end of this form.
If you have any questions related to this form, please send them to
gefs@ccsdot ukydot edu
For additional information see http://gefs.ccsdot ukydot edu
******************** Personal Information ********************************
Name :
(it will be publicly available ONLY with your approval, see the end of
this form)
- --------------------------------------------------------------------------
Address (it will not be publicly available):
- --------------------------------------------------------------------------
Country:
- --------------------------------------------------------------------------
E-mail(it will not be publicly available):
- --------------------------------------------------------------------------
Level of the meteor observation experience: not experienced __
somewhat experienced __
moderately experienced __
highly experienced __
- --------------------------------------------------------------------------
Have you ever heard electrophonic sound before?:
- --------------------------------------------------------------------------
******************** Description of the Observational Site ***************
Location of the observational site (give exact coordinates, if known)
general description:
Longitude: Latitude: Elevation:
- --------------------------------------------------------------------------
Describe in detail the meteorological conditions at your observing site
(temperature, humidity, wind, rain, clouds, etc...):
- --------------------------------------------------------------------------
Describe in detail your observing site (vegetation, buildings, fences and
(especially) any metal objects in your vicinity, etc...) :
- --------------------------------------------------------------------------
Describe in detail your outlook and clothing during observation(especially
important is your haircut, glasses and metal objects) :
- --------------------------------------------------------------------------
Specify all electrical equipment at the observational site and in its
vicinity :
- --------------------------------------------------------------------------
Your additional remarks about the observational site :
- --------------------------------------------------------------------------
******************** Details about the Electrophonic Sound ***************
Specify the date and time of your electrophonic observation :
- --------------------------------------------------------------------------
How would you describe the electrophonic sound you heard?:
- --------------------------------------------------------------------------
How long did the sound last? :
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Which direction did the sound come from (the meteor, the ground, some
object, air, all directions)? :
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How many observers from your vicinity heard the same electrophonic sound,
and how many observers did not hear it? :
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Did you see the meteor that could be connected with the electrophonic
sound?
Yes, simultaneously with the sound __
Yes, a moment before the sound __
Yes, a moment after the sound __
I can not decide which meteor was connected to the sound __
No __
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If YES, what was correlation with the light maximum?
I can not decide __
The sound was SIMULTANEOUS with the light maximum __
The sound appeared BEFORE the light maximum __
The sound appeared AFTER the light maximum __
- --------------------------------------------------------------------------
Did you notice any other unusual phenomena which might be related to the
meteor (electric or magnetic effects, strange odors, unusual animal
behavior, strange air glow, etc...)? :
- --------------------------------------------------------------------------
******************** Details about the Meteor ****************************
************* (if you have seen or detected the meteor) ******************
Meteor shower (or sporadic) :
- --------------------------------------------------------------------------
Meteor magnitude :
- --------------------------------------------------------------------------
Velocity (enter the exact value if it is known):
very slow __ slow __ fast __ very fast __ static __
- --------------------------------------------------------------------------
Color :
- --------------------------------------------------------------------------
Fragmentation :
- --------------------------------------------------------------------------
Trace duration :
- --------------------------------------------------------------------------
Height above horizon (from 0deg to 90deg):
- --------------------------------------------------------------------------
Azimuth (from 0deg to 360deg):
- --------------------------------------------------------------------------
Angle between the meteor and horizon (from 0deg to 90deg):
- --------------------------------------------------------------------------
**************************************************************************
At the end we would like to thank you for your patience and cooperation.
If you have any comments, remarks or suggestions on how to make this
survey better in future, please mention them here.
**************************************************************************
With submitting this form you agree to make your report public.
Do you agree to use your name as a public reference to the data that you
are submitting? (If you mark nothing or both, it will be assumed that you
agree.)
YES __ NO __
Your address and e-mail will not be made public, and we will keep it only
for the case of gathering additional information from you.
**************************************************************************
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