Expert: Tom Whiting - 12/12/2008

Question
How long, on avg., is the the light trial emitted by a meteorite (shooting star) as it enters the earth's atmosphere?  

Answer
Hi Serenity,
There are too many variables to determine an 'average' length of
a residual "meteor light trail". Whether an incoming meteor even leaves a visible light trail depends on it's size, composition, entry angle, entry speed, and maybe even more variables I can't
think of. (Another big variable would be how much light pollution
is present...city light glow, bright moon present in the sky...all
these hamper observations of very dimly lit objects, including
meteor light trails).

Most (99.999%) incoming meteors are a grain of sand size or smaller, with the consistancy of 'cigarette ash', and they typically don't leave any visible light trail. Only the larger meteors, grape size, walnut size, baseball size...which only constitute less than 0.0001% of incoming objects, are capable of leaving a visible light trail for us to see naked-eye.
So since there are millions of sand grain size meteors per day,
compared to only a few of the larger sizes, the answer for
the 'average' length of a visible light trail, would be very near zero.  And even the few "big" ones sometimes don't leave a light trail either, because of all the variables mentioned above.
In 50 years of observing, I've only seen two or three that leave a
residual light trail for over 30 seconds. Most of the few dozen or so
that I have seen, the visible light trail lasts only a matter of
a few seconds, but no more than 10 seconds...in naked eye visible light.  So I guess the accurate answer to your question is very near zero.
Oh, just a word on terminology...they are called meteors, not
'shooting or falling stars' as they have nothing to do with stars.
(So we try to avoid the terms shooting or falling stars today).
Call them by their proper name, meteors.
It's simply 'space junk' hitting our atmosphere. And they are not
meteorites....they are called meteoroids before striking the atmosphere, meteors while giving off light and heat, and if perchance they strike the surface of the Earth, only then they are called 'meteorites'.
(So Meteor Crater out in Arizona is a misnomer...it should really
be called Meteorite Crater).
Hope this helps,
Clear Skies,
Tom Whiting
Erie, PA