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Re: (meteorobs) flaming meteors
Title: Re: (meteorobs) flaming meteors
As I see it, a meteorite which strikes / enters the ground at an angle has not had a period of 'dark flight' as it still has residual initial velocity. 'Dark flight' presumes movement only under influence of gravity and wind resistance, therefore must be essentially vertical.
By way of example, the Guyra (Australia) meteor last year as well as the Peekskill meteor both struck the ground at quite an angle. I didn't see any photos of the Guyra ground impact, but from the photo of the car struck by the Peekskill meteor I would estimate the angle of impact at less than 30° to the ground.
If the meteorite still has significant residual velocity it can then be of any temperature. Further, had the peekskills meteor hit the atmosphere perpendicularly, its trajectory would have been greatly shortened which would further reduce the cooling effect, and would enhance the heating effect. From the video it appears that that meteor hits the atmosphere at around 5°; a 90° entry would have a trajectory shortened by a factor of eleven, in a 'flat' atmosphere. The curvature of the earth / atmosphere would work to make the shallow trajectory even longer; the vertical entry even 'relatively' shorter.
What do others think? Would appreciate any others comments, except 'appeals to faith' ;-).
Stuart.
Tom said;
It might be best to respond the the inquiring public by saying that meteors are only flaming at impact when Hollywood makes a movie.... Much more dramatic that way and that is what the general public expects to see.
It does still raise a point that has yet to be answered satisfactorily at this site (to my knowledge). At what point (range of masses) does a meteor (let's say a stony iron) have sufficient mass to retain most of its hypersonic velocity and heat to the earth's surface. Obviously the dinosaur killers did it but there is a lower limit. Any discussion?
I'm thinking the damage zone wouldnt be a burning corn field or an acre of scrub - but rather a sizable crater with a surrounding region burned by superheated air -
Would it be railroad car size at impact -- passenger car size -- Hayden museum specimen size??
Some suggested the grazer over the Tetons in 1972 might have been sufficient for that.
Tom
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