(meteorobs) Definition of a meteor (was Re: Fifth grade sciencebook)

[Ed Majden]

on 4/28/05 9:52, GeoZay at aol.com at GeoZay at aol.com wrote:

> The definition I found on IMO's website doesn't seem complete. But I  suppose
> this would be to include interstellar objects as well?  Anyways, after the
> light phase and while in the dark stage, the then  falling object is no longer
> in interplanetary space...it's in the earth's  atmosphere dominated by the
> earth's gravity.  At this point, I'm  hard pressed to see how the sun is gonna
> jerk the falling object back into  interplanetary space thru any gravitational
> influence or velocity of the  object? Other definitions I've seen for a
> meteoroid included the small object  to be in solar orbit. Again, objects in
> the dark 
> stage are no more in  independent solar orbit than a sea gull. They both are
> at the mercy of  the earth...not the sun.
> 

George:
    Definitions can be tough!  Even professionals have heated discussions on
this and similar topics, thus the IAU Nomenclature Committee.  I WISH they
would publish their definitions on the web!  This has not even been given
consideration I'm told.  As I see it, any object in orbit around the Sun, be
it in space or sitting on the Earth's surface is influenced by the
gravitational effects of the Sun.  True, it is now not in an independent
solar orbit as you put it.  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?
    The definition of what is a meteoroid or asteroid is still a gray area.
Was 60 tonne Hoba an asteroid or a meteorite.  In publications both terms
are often used.  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?  Very hard to define unless you know the
entry velocity of the object.  Micrometeorites confuses the situation even
more.
Ed