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Re: When it's a rock! (was,"RE: When Does a Meteorite become a Meteorite?")

In a message dated 99-09-11 16:40:46 EDT, you write:

Ginger<<  When it's a piece of space
 junk coming through the atmosphere making the light what do we call it?  
(Assuming
 you could tell the difference between space junk and a real rock from space, 
in
 flight.) <<

Ginger, I refer to these objects as "pieces of re entering space junk". The 
difference of reentering orbiting space junk and a slow meteor is quite 
distinct really. Below are some of the differences to look for:

1)Re-entries are rarely if ever brighter than -8 magnitude and typically last 
for many tens of seconds, going from horizon to horizon usually with dozens 
of fragements trailing.

2) While some meteoric fireballs may be of long duration with numerous 
fragments, they would typically be very much brighter than Venus.

3) A fireball lasting a few seconds is unlikely to ever be a satellite re 
entry.

4) Is the path consistent with a predicted satellite re-entry? It would be 
rare for a reentry to follow an east to west path.

5) If the velocity can be calculated, a satellite renentry will be below 8 
km/sec, whereas a meteoric fireball will be above 11 km/ec, and often well 
above. Visually, a satellite with a re-entering velocity of less than 8 
km/sec is very noticeable when compared to a meteor velocity over about 18 
km/sec. They pretty much look like the velocity you normally see for 
satellites in the evening or mornings.

ginger>> Most of us amateur astronomer types call all of the smaller ones
 *shooters* out in the field - the big ones are *fireballs*.  Sometimes you 
hear
 *bolide* from the more academic folks.<<

I don't have a "pet" name for non fireball meteors other than perhaps a short 
nickname for it's shower membership or simply "sporadic". For example, I 
might refer to a Quadrantid as simply as a "Quad", or an Eta Aquarid as 
simply as an "ETA".
GeoZay

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