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RE: 'Double helix' meteors

Hello Bjørn,

I would really like to reply your questions, but I'm reluctant to do so on
this "List".  You really should post this on the Meteorobs List.  Lew Gamer
can have your questions posted on his list without you having to subscribe.
In doing this, Lew will have a provision in his "introduction" of "your
post" that, since you are not a subscriber, all replies will have to include
your email address.
Like myself, many on this List subscribe to Meteorobs, as well.  If sometime
in the future I want to retreive your message, I shouldn't have to resort to
searching both archives.

Bøb V.
"To either SUBSCRIBE or UNSUBSCRIBE from the 'meteorobs' email list, use the
Web form at:
http://www.tiac.net/users/lewkaren/meteorobs/subscribe.html "
  

-----Original Message-----
From: Bjørn Sørheim [mailto:bsoerhei@online.no]
Sent: Thursday, November 04, 1999 1:12 PM
To: meteorite-list@meteoritecentral.com
Subject: 'Double helix' meteors



Hello list,
Please note that this message is posted in the meteorite
list, so don't carry it over to something like the meteor
observer list which I have not and don't intend to 
join - because of all the lists I already get.

The title does not have any thing to do with life in
meteorites, as I might have mislead some to believe.
Rather it's a special type of meteor I observed during
the (early - the bright ones) Leonids of last year.

It was seen at about 3 am MET (= +1 GMT), that is about 
1 hour after the later found time of maximum rate.
What I saw was a very bright meteor, maybe about -5 to -8 mag. 
Definitely one of the many Leonids at that time, coming right 
from the radiant point. But this one was not only a very bright
meteor, it also had split in two. Added to that, each of the 
parts rotated at a fast rate, so as to make a close double 
helix. These were not intertwined (as in DNA), but
travelling in a spiraling but straight line side by side.
The apparent diameter of one helix I judge to be about 1/4-1/2 moon
diameter. Let's asume that they were formed at a height of about
100 km. I have not been thinking about this before lately, but these
figures means that the glowing particles must have been travelling a 
considerable distance - sideways, going in a helix path and considering
the helix was easily visible to me standing 100000 m below! 
Making a quick calculation assuming the helix diameter was ~10', we find
that it was travelling in a circle with a diameter of 291 m (~300 m) 
perpendicular to its forward path.
(I will not try to calculate its rotational speed.)
I will only point to the fact that this observation could only be 
possible if the meteoroide material was volatile - that is cometary.
Why, because a particle going like that would have had to have a 
propulsive force of its own which would have had to be centered clearly
off the center of mass. The only material that fits these characteristica 
is - cometary.. 
(We already knew of course that the Leonids were cometary).
By the way, the sight of this meteor reminds me very much of the paths of
charged subatomic particles travelling along magnetic field lines..

I guess four characteristica would have to be present for such meteors
to be seen.
1) Be of cometary material (very usual)
2) There were many (sometimes)
3) They had to be bright (big particles) (unusual)
4) They had to be rather fast ( sometimes )

I guess it was the combination of the last 3 facts that produced
the special kind of meteor I observed.

I only wonder, how common is a meteor like this, and were many others seen
during the Leonids?

Bjørn Sørheim

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