[meteorite-list] Huge Daylight Fireball Video?

From: Chris Peterson <clp_at_meteoritecentral.com>
Date: Mon, 18 May 2009 09:52:30 -0600
Message-ID: <C3EDD6F241104C29981199F5C6F63732_at_bellatrix>

In fairly still air, contrails persist until they evaporate. How long that
takes depends on the humidity and water content of the air. I use contrail
patterns during the day as a tool to assess probable astronomical seeing
conditions that night. I'm looking for still, dry air. I know that's what
we've got when airplanes leave no contrails, or leave contrails that only
persist for a very short distance behind the plane- like what the video
shows. Here over the central Rockies, such short contrails are very common.

Contrails normally form off the trailing surface of the wings, and spread
out with distance. In still air, they may spread very little, and appear to
taper away again at the far end. But what you usually see then is a small
start, some broadening, and then the taper begins. This thing in the video
seems too large at the start, which is why I speculated that something was
being vented.

That said, it's also possible the problem is optical. The camera optics
don't seem very good, and the image doesn't seem well focused. So the
apparent blob of material at the head might just be an optical aberration of
some sort.

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message -----
From: "Meteorites USA" <eric at meteoritesusa.com>
To: "Chris Peterson" <clp at alumni.caltech.edu>;
<meteorite-list at meteoritecentral.com>
Sent: Monday, May 18, 2009 9:38 AM
Subject: Re: [meteorite-list] Huge Daylight Fireball Video?


> Yeah, I though it odd.... Hence the ? mark.
>
> I did notice the sun setting (or rising) and thought this could possibly
> explain the orange glow of the "fireball" if it is contrails reflecting
> the orange glow from beyond the horizon.
>
> Still though, if it were a contrail from an airplane wouldn't it persist
> in the air longer than it does? The "tail" of this fireball seems to stay
> the same length through out the video and not stretch out across all the
> way across the sky like a contrail would. Why is that?
>
> Don't contrails from planes tend to get larger further from the aircraft
> as the trail expands and dissipates in the air? This video shows a
> tapering of the short "contrail" seemingly getting smaller the further
> away from the object. What would cause that?
>
> Or is it only seeming to taper off because of the haze in the air
> explaining why the longer "contrail" is not visible as well?
>
> Regards,
> Eric
Received on Mon 18 May 2009 11:52:30 AM PDT