(meteorobs) How "large" is that meteor?

[Roberto G.]

From: "Geert Barentsen" <geert.barentsen at pandora.be>
To: "Global Meteor Observing Forum" <meteorobs at meteorobs.org>
Sent: Sunday, March 27, 2005 11:39 PM
Subject: Re: (meteorobs) How "large" is that meteor?


> Hello Jeff,
>
> Interesting question, I have never wondered about this before.
>
> Here's a wild guess. Let's say we have a homogeneous, tangential,
> cylinder-shaped meteor trail. According to a quick sketch and my rusty
> geometry, the diameter d could be written as:
> d = tan(alpha) * ( h / sin(beta) )     with alpha = apparent width at the
> sky (arc degrees), h = meteor height, beta = angle between horizon and
meteor.
>
> For a typical meteor (90km high, 60 degrees above the horizon), an
apparent
> size of 1 arc minute would correspond to a trail diameter of +- 30 meter.
>
> But once again, this is only a wild geometric guess. I find it hard to
> estimate the apparent size of a typical meteor. Also, I have no idea about
> the relation meteroid size/speed <-> trail width.  Surely some people on
> this list will be able to tell us more.
>
> Geert
>
>
>
>
> At 07:56 27-3-2005, you wrote:
> >The various text that I've read (not all by any means) speak of how
> >meteors range in size from a pea to a fist sized rock etc.  What I've
> >never read and maybe someone can tell me is how large is the area in
space
> >that we see illuminated(width wise not length wise) approximately
> >understanding that it is different for each meteor.
> >
> >
> >Jeff W.

Sorry for the bad English.

The trail can to be long 400 Km or more, for the large I read
sometime dimensions of some dozens of meters as wrote Geert, for
the fireballs dimensions too more of 1-2 Km. But we must remember
that this it's the sensibility of human eyes, if we have infrared
eyes we should see meteors more biggest, and perharps more in radio
waves. The same occur with photos, more it's the sensibility of a
film more big it's the dimensions of the meteor in it.
Roberto Gorelli