(meteorobs) Definition of a meteor (was Re: Fifth grade sciencebook)
GeoZay at aol.com
GeoZay at aol.com
Thu Apr 28 13:54:15 EDT 2005
>> What about the meteoroid that skipped out of the
Earth's atmosphere in 1972? Is it no longer a meteoroid, as it spent some
time in our upper atmosphere as a fireball/meteor? What would you call it
now?<<
I'd still call it a meteoroid. This object never entered the dark phase of
flight. The discussion was about those objects that have and entered free fall
flight. Since it was incandescent all the while in the atmosphere and left
the earths influence, it still has an orbit of its own. The earth doesn't own
it....it was just saying "Hello". :O)
>> The definition of what is a meteoroid or asteroid is still a gray area.
Was 60 tonne Hoba an asteroid or a meteorite. <<
At this size, the object always had a considerable amount of cosmic velocity
all the way to the ground. It probably never left the light phase. It never
was just a falling object. Since the 60 ton Hoba meteorite is less than 10
meters in size, I'd still call it a meteorite. In the IAU glossary of
definitions, they define a meteoroid to being larger than an atom or molectule, but
smaller than 10 meters. If larger, it's refered to as an asteroid. From the
pictures I've seen of it, it appears to be less than 10 meters.
>> As far as we know, all recovered meteorites are asteroid
fragments unlike Cometary meteors. Should there be a separate definition
for either type of phenomenon?<<
Yes...if there is something different about them that would permit a
distinction. Meteorites are already catergorized by their types and sub types. If a
Cometary meteor had a look that was remarkably different from that of an
asteroidal meteor....then yes, a nomenclature should be made to show the
distinction.
George Zay
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