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(meteorobs) Fw: [MIAC-L] re simultaneous meteor sounds.

    With Dr. Jeremy Tatum's kind permission I am forwarding a message he
sent to the MIAC list regarding the paper, "Instrumental Recording of
Electrophonic Sounds from Leonid Fireballs", by Zgrablic et al.  I thought
that the readers of meteorobs would find his comments interesting.  I will
forward any serious comments to him.

Ed Majden


----- Original Message -----
From: * JEREMY TATUM Subject: [MIAC-L]


 Hello, All:

       I have read the paper "Instrumental Recording of Electrophonic
 Sounds from Leonid Fireballs" by Zgrablic et al.

       Since I am perhaps Unbeliever-in-Chief in the alleged phenomenon,
 maybe I should comment.

       It may surprise those who have heard me discuss this topic
 before that my impressions of this paper are remarkably positive.
 I would have to say that is the ONLY paper I have seen that comes close
 to being a convincing demonstration of the reality of electrophonic
 sound.  Most evidence to date, copious though it may be, has been
 anecdotal and nowhere close to meeting normal scientific criteria.
 I have long insisted that, however many anecdotal stories we hear,
 there has not to date been convincing instrumental detection of
 undoubted electrophonic sound, and this is indeed recognized by the
 authors.  Their paper does supply convincing evidence of the
 reality of simultaneous sound and its instrumental detection under
 carefully-controlled and designed scientific experiment.

     The observations used human observers, acoustic detectors, and EM
 detectors simultaneously, all under controlled conditions, and stringent
 conditions were placed on what was accepted as a successful detection.
 Two successful detections of meteors seen and heard and recorded
 simultaneously by acoustic detectors were achieved;  simultaneous
 electromagnetic detection was not obtained - either because the detectors
 were insensitive at audio frequencies or because the Keay mechanism is
 incorrect.

     Members will have to read the paper in full to get all the details,
  but I would have to say, as Unbeliever-in-Chief, that this has come
  far closer to convincing me than anything to date.   I would not go so far
  as to say that this establishes the phenomenon once and for all beyond
 all possible doubt in the sense that no one ever need to repeat similar
 observations.  Indeed the paper has established that further experiments
 of this nature are highly desirable and a worthwhile scientific pursuit.

     I would venture a few small comments.  Offhand, I would have thought
 that shower meteors of cometary origin were rather less likely to produce
 electrophonic sound than a genuine asteroidal fireball, and therefore that
 claims of electrophonic sound from shower meteors need a particularly
 high standard of proof.  Also, since Leonid meteors were occurring
 almost continuously at the peak of activity, coincidence between
 visual, aural and instrumental detections were likely - although the
 authors placed stringent constraints on temporal coincidenceand took
 into account the different qualititative natures of simultaneous and
 delayed sound.

     I would criticize the claim that "the phenomenon has been firmly
 accepted as physically real".  This is not the case.  It may have been
 firmly accepted by some, but there are still scientists who are not
 fully convinced and some who are downright disbelievers.  Further work
 in the area is undoubtedly necessary before the reality of electrophonic
 sound can be placed on as firm a footing as the Third Law of
 Thermodynamics.

     I also INSIST - and it is all the more important now - that
 simultaneous sound must not be described as "electrophonic sound"
 unless it has been unequivocally shown to have been electrophonic,
 nor must it be dismissed as "psychological" unless it has been
 unequivocally shown to be psychological.  In nearly all cases, all
 that has been established is that a witness has reported SIMULTANEOUS
 SOUND, and that is the phrase that must be used to describe it unless
 there is proof that it is either electrophonic or psychological.  If
 anyone claims that ALL instances of reported simultaneous sound are
 electrophonic and none are due to faulty observation or imagination,
 then I'm sorry - my response is that I don't believe it for a moment.
 (Martin, you may recall that I mildly mentioned this to you with
 respect to your and Luigi's paper on 900-odd instances of
 "electrophonic" sound!)

 I also feel that the word "fireball" should not be used (notwithstanding
 the IAU definition) for shower meteors of cometary origin.  Meteors
 brighter than -4 can be seen any night, and in any case no one can
 possibly estimate their magnitude  (The Croatian observations MEASURED
 their magnitudes.)  The word fireball should be restricted to
 genuine fireballs of asteroidal origin and are of meteorite-dropping
 potential.

 In any case, while I do not believe the book is closed on this topic,
I believe the Croatian observers are to be congratulated on their excellent
and thorough experiment; a few more like that, and few doubters will remain.

                                 Jeremy


> PS I see that dejan is requesting reports of reported simultaneous
> sound.  I am a Web-hater, so I am not strongly motivated to contribute
> to the web form, but I did record, in Pub. Astron. Soc. Pacific 112,
> 1487 (2000) the circumstances of the seven reports of simultaneous
> sound described for the 1998 April 15 Vancouver Island fireball.

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