(meteorobs) "Corkscrew Meteor" on Space.com Image of the Day 7thJan

[R Kramer]

On Sun, 9 Jan 2005, Jim Pettit wrote:

> Seems to me that, if the appearance of the corskcrew is simply due to the
> oscillation of the drive motor, it would have to be a pretty erratic
> mechanism to display such a wide variation in that oscillation over such a
> small period of time (a tiny fraction of a second). The left end of the
> trail shows very little 'corkscrewing'; there are just a few waves and
> crests just left of middle; the line is fairly flat to the right of the
> middle; and, obviously, the right 30% of the trail is very 'corkscrewed'. In
> my many years of observation, I've seen several meteors which displayed
> aerodynamic inflight changes to their ballistic trajectories; while I've
> never seen a meteor corkscrew, I have no trouble believing that such a thing
> could certainly happen, given the correct meteor composition, shape, and
> angle of entry.

The apparent blurring of the star images which appears to be coangular
with the corkscrew axis would seem to support the suggestion that periodic
camera displacement (i.e. vibration) is a likely explanation. Further,
there is no reason that any such displacement need manifest as a single
frequency, sinusoidal displacement. If more than one resonance were active
(not unlikely) net camera displacement, and the resulting corkscrew, could
easily appear to be "irregular" in amplitude or period or both.

Even granting the assumption that a source of lateral acceleration
sufficient to produce a corkscrew trajectory could exist, it would take a
truly bizarre set of coincidences to produce a trajectory consitent with
the image, i.e. a corkscrew with a fairly constant radius but inconstant
period.

Richard