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Anomalous Meteor
By Pierre Martin
Here are my feelings to some anomalous meteors according to the observing
experience I have (although some of these observations are controversial).
Wavering meteors
These are perhaps real (but under debate). I am not talking about curved
meteors or those completely changing directions. Curved meteors are a
different story. A wavering meteor will still follow a straight trajectory,
but will appear to zigzag or ripple *slightly* as it travels. The problem
with this is that a meteoroid cannot survive the slightest change in
directions, due to the extreme velocity it travels as it burns in the
atmosphere. For some unexplained reason, I have observed this effect subtly
on a small number of meteors, but only one was very obvious. It is still
fresh in my mind. In July 1994, while observing in the late evening from my
backyard, a magnitude -2 slow speed sporadic in the northeast caught my eye.
It was a long persistent 30 degrees path, lasting a few seconds. I had time
for a good long look at it, so optical illusion or atmospheric effect is out
of question. The meteor traveled about parallel to the horizon, and
"wavered" back and forth quite obviously at least 3 times before fading out.
Could this effect be caused by the meteoroid spinning as it plunges into the
atmosphere? I always believed this was the cause, but I have trouble
understanding the exact process? Photographic evidence is available. A good
example is a wavering Perseid shot in Capricornus on page 90 of the August
1997 Sky&Tel. It looks quite convincing to me. The caption beside the photo
claims that at least 1 out of every 200 meteors follow a slightly wavering
path. Wonder where that data came from? Has there ever been any research
into this topic?
Curved meteors
I have noticed on several of my older reports going back years ago, I often
mentioned as remarks that I have seen a curved meteor. Years later, there
were seen less often, and now I never see this effect anymore. I believe
somehow my eyes were tricked into seeing curved paths when I would turn my
head quickly to see a meteor already moving...a well known optical illusion.
Another factor are birds and insects. For instance, on August 4/5 1992, I
observed an amazing "S" shaped path from a meteor of magnitude 3 that lasted
at least a few seconds. It even originated from near the Perseids radiant. A
number of nights later, I saw a similar meteor but soon realized to my
disappointment that it was only a bird flying around, under lit from street
lights. I still have my 1992 Perseids plotting chart with all meteors
linear, except for that strange bird plot going all over the constellations.
I might still see curved meteors on occasion, but never note them anymore as
I know they are not real and immediately dismiss them.
Double meteors
These are quite rare and breathtaking. There is a difference between
"double" meteors and simultaneous ones, often seen during major showers such
as the Perseids or Leonids. The difference with double meteors is having at
least two of them travelling very close together on similar paths, and both
meteors with very similar magnitudes, trains, ect...
Only twice I observe these double meteors. One of the most visually
breathtaking event of my years of meteor observing so far came on the
evening of May 4 1991. At 22:45 EDT, the Eta Aquarids radiant still some 20
degrees below horizon. Suddenly at that time, I noticed two bright meteors
appear at the same time low in the east. They were strikingly similar. Both
brightened to yellow-white magnitude -3 or -4 as they travelled together
quickly straight up to the zenith, separated by 5 degrees. They kept racing
and I had to turn my head to keep following them! The first one extinguished
after about 80 degrees. The second one went further going well over 100
degrees path. Both left brief but brightly glowing trains behind.
On August 20, 1988, evening 23:00 EDT, I observed another long path "double"
meteor. This time, these were only magnitudes +3, but still impressive. Both
meteors began instantaneously near Cygnus, separated by a few degrees only,
and plunged together into the eastern horizon. They seemed to converge
together as they got further away near the horizon. They quickly disappeared
behind the neighbour's house. Their visible path went at least 80 degrees.
Earth grazers
These are actually quite common, especially during the peak of a major
shower when the radiant is at or just below the horizon by a few degrees.
During that time, meteors are usually more scarce but some spectacular long
paths can appear. Some paths can travel more than half the length of the sky
or perhaps more. A few more nice earthgrazers I have seen... On May 4/5
1992, shortly after midnight, a high velocity grazer of magnitude +2,
possibly from the Eta Aquarids, shot over 100 degrees in the sky. While
observing on October 4/5 of that same year, I got a medium speed +2
magnitude sporadic covering almost 130 degrees of sky, from Orion to the
northern horizon! It just kept going and going! On April 19/20 1996, there
was a very nice sporadic of +1 magnitude on a 90 degrees path. More recently
last year, during the night of April 30/May 1st 1998, at 7:38 UT (3:38 EST)
were 2 similar ETAs only 10 seconds apart. The first one, close to the
zenith, split the sky with 60 degrees or more in no time. The second one
followed in almost the same location and shot some 35 degrees.
Meteors "slowing down"
I suppose these are simply the effect of foreshortening from meteors close
to a radiant, or from long meteors travelling further away, and appearing to
slow done. Usually they also get fainter as they become more distant. One
interesting and different one I saw deserves mention. It was during the
Geminids on Dec 13/14 1988. I was observing around 21:30 local EST, when
this bright meteor shot fairly fast from near Gemini and descended on a long
path beyond Orion. Oddly, as it descended and slowed down toward the
horizon, it actually got gradually brighter. This yellow-white "ball" seemed
to come to a near stop, with a magnitude reaching -4 or more, then it
suddenly blinked out. There were no hint of any train. It looked just like a
Roman candle firework.
Electrophonic sounds
Only once. It was a July 1985 evening observation (boy, that was looong
ago). After a quiet evening of watching for satellites and learning
constellations, I was about to quit for the night, when suddenly it
happened. A large fireball in the south, brighter than Venus was immediately
accompanied by a loud, clear "whooossh". A sound much comparable to the
propane burner of a hot air balloon. The fireball had a "thick" appearance.
It was yellow-white and with a bright 20 second train following. It left no
doubt in my young mind that the sound was associated with the meteor. Things
were quiet around at the time, and there were no indications that something
else would have produced the sound. The neighborhood where I observed at
that time had several electrical lines on poles passing over my backyard.
For that reason, I still don't rule out the possibility of a real
electrophonic event.
"Skipping" meteors
As I observed the Ursids on December 22 1988, in the early evening after
sunset, I saw what looked like a strange faint Ursid meteor appearing in and
out quickly at least 5 times, much like a rock skipping on a pond. It left
me wondering if it could be really a meteor. I then went to sleep, and woke
up to observe the last hour of darkness before dawn. Despite observing
through a bedroom window, with a full moon (!) and awful limiting magnitude,
it appeared the Ursids were putting on a show. I was surprised by a few nice
meteors. Perhaps the most interesting was another "skipping" meteor at 6:40
local EDT; this time a -2 magnitude yellow-white Ursid that flashed about 5
times. I suppose meteors don't really skip. This feature is probably caused
by faint meteors suddenly flaring to visibility as they move.
Nebulous meteors
I sometimes see a meteor surrounded with a faint "halo", especially some
bright ones. I believe most of the time, this is a result of atmospheric
haze. Or perhaps a glare into my glasses. Ever since I began wearing contact
lenses while observing, I noticed much less problems with reflections. I
also find that everything looks sharper and more pinpoint with contact
lenses compared to glasses, despite identical prescriptions with both.
Vivid colored meteors
I nearly always see color in meteors with magnitudes of +2 or brighter. I
also consider white as a color. Magnitudes +3 are more rarely colored and
for anything fainter, I barely, if ever see any color. Most of the time, the
color observed is subtle, usually comparable to naked eye star color. More
unusual, but not rare are the really vivid colored meteors. I seem to have
observed the most vivid green meteors in December for some reason. During
the Geminids peak night of 1988, I had 2 strongly colored green meteors of
magnitude -3. Even the trains they left had a slight greenish tone. For the
early morning hours of December 22 1988, I saw 2 Ursids of magnitudes -2 and
-3, also with vivid green colors. Much more recently last year, I was
heading out to Casselman to observe on Dec 12/13. It was shortly before
local midnight and as I drove on, a Geminid fireball of magnitude -8 to -10
went by with a brilliant deep green color! |