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Re: (meteorobs) New Member Peter Stinson & Request for Info...
Hello again Peter,
Lew's post reminded me that The federal government maintains a web site, with access by permission, which forcasts time and location information for reentering major artificial bodies-- aka space debis.. This may be another resource ultimately in your decision making trees you eventually develop.
Regards,
Elton Jones
Lew Gramer wrote:
>
> Hello, Peter, and a warm welcome to the list!
>
> Your team faces a very difficult problem - the same problem that "fireball
> chasers" face when trying to glean useful data from public sightings. In your
> case though, lives may depend on making the right call from the data!
>
> I know some of our Olde Meteor Salts will have more to say in response to your
> question, but I'll just try to give my $0.02: first, if the event is observed to
> deviate in any significant way from a straight (Great Arc) path across the sky,
> then it is not a meteor: celestial meteors enter the atmosphere at *minimum*
> velocity 11 km/s, and any force which could conceivably shift their visible path
> would very likely destroy the object in the process.
>
> (Note the persistent trains or "afterimages" sometimes left behind by meteors
> HAVE been known to appear "split" or "kinked", particularly after a few minutes
> in the high winds of the upper atmosphere. But I'm talking here just about the
> visible light path of the event itself, lasting seconds or less.)
>
> Second, if the event is seen to "hang in the sky" - i.e., travelling with an
> angular velocity below a couple of degrees per second, but still lasting more
> than a second or two - it is very likely not a meteor or an artificial reentry.
> It is POSSIBLE that an extremely foreshortened meteor path - particularly one
> which leaves a persistent train - will appear this way. But very rarely.
>
> Finally, there are other things making an event LESS likely to be a meteor,
> while not eliminating that possibility altogether: for example, an event which
> is seen with a high angular speed in the early evening is unlikely to be a
> meteor or an artificial reentry (space junk enters the earth's atmosphere
> travelling far slower than meteoroids do!) By the same token, an event with a
> very LOW angular speed more than a couple of hours after midnight is less likely
> to be a meteor - although again, foreshortening can invalidate this "rule".
>
> Well, you can count on the more experienced readers to correct me where I stray,
> Peter. :) But in the mean time, I hope this helps some!
>
> Clear skies and quick rescues!
> Lew Gramer
> Medford MA
>
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