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(meteorobs) "Watching" bolides descend from the sky??


Since we're on the subject of meteorites (the List Admin sneakily posted),
I read a fascinating account of the great Portales meteorite fall in one
of the "Big 2" astronomy magazines this month... I enjoyed it, though I'm
not a particular meteorite enthusiast. But there were a few details that
troubled my reasoning faculties a bit.

Those who haven't read the article may want to browse through it before
reading this post any further... I could never summarize all the details
of such a well-written, detail-rich article. Still, maybe some familiar
with public bolide sightings can reply without reference to the article.


Of the several public accounts of the fall, every one described in vivid
detail *watching the fireball streak overhead*, immediately preceding the
actual strike. Reading the article carefully (and assuming the author was
as good at summarizing scientific detail as descriptive detail), I found
that the original meteoroid that caused the Portales was perhaps only one
meter across, and was moving a glacially slow (for a meteoroid) 10 km/s.

(For comparison, remember that most shower meteoroids hit us at more like
25-40 km/s, and the Leonids whip into earth at a belly-burning 71 km/s!)


How on earth (or above it) could such a SMALL object traveling so SLOWLY
manage to maintain sufficient velocity to ionize air all the way to the
ground?? Now let's discount for the moment the very real possibility that
the good, hard-working folks of New Mexico may have simply been letting
their imaginations fill in some of the blanks in what they saw...

[
I know this is a big assumption. Browse over our "Did I see a fireball
land?" item on the "FAQ" page of the 'meteorobs' Web site, and you can
see that untenable tales of fireball "falls" are not new to our list!

    http://www.tiacdot net/users/lewkaren/meteorobs/fireballs.html
]


But discounting that possibility for a minute, I wonder if it's possible
fragments of Portales may in fact have simply been in free fall, and yet
still either GLOWING or maybe just TRAILING SMALL DEBRIS as they fell?
This explanation would not fit with the descriptions of many witnesses,
including two gentlemen who saw the bolide from an airplane, who actually
describe seeing the "smoking trail" pass OVERHEAD. But perhaps with some
trick of perspective - plus just a touch of imagination - a free-falling
debris cloud may actually have SEEMED to move overhead?


I know I'm stretching the bounds with this explanation... But otherwise,
I seem to be left with one of two tough conclusions: more than one group
of people all "filling in the blanks" with very similar imaginings; or
else a small, slow object somehow maintaining celestial velocity through
at least 20 or 30 km of dense atmosphere. I'm willing to accept Door #1,
if I have to - since Door #2 seems physically impossible. But I'd rather
have a third door to choose from in this case. :)

Clear skies and happy discussing!
Lew Gramer

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