no57va@shaw.ca wrote:Innitial mass and speed and friction are a factor in determining final velocity. By the time it got here it traveled through the atmosphere at a minimum 30,000 miles an hour like, most space objects that are not in an initial orbit. Nickle iron is heavy enough that the object could have weighed very little, a gram or so, but initailly was a few kilos of very heavy iron meteor. This is speculation of course without proof. The calculations for this hypothesis can't be too hard. The object might have had a higher initial velocity upon entrance to the atmosphere. The combination of material could have been alot of things.
OK, it's your right to be sceptical, but I think perhaps you should ask yourself what
would disuade you from this hypothesis.
As you suggest, the calculations are not hard. If you go to
http://www.lpl.arizona.edu/impacteffects/ you will find a meteroite impact simulator that lets you play around with initial conditions like density, initial speed and angle etc.
People can go there and try to set up initial condition where only a tiny fragment hits the Earth at a decent speed and produces anything like the results you predict.
You are postulating a condition where the objects starts with high mass and velocity (and hence kinetic energy and momentum), then almost completely burns up in the atmosphere hence reducing its mass to a near zero amount, yet retains sufficient speed to produce effects upon impact that are easily visible from 500m away, but show no lasting effects 15 seconds later and no visible damage upon inspection.
The problem you face is that when an object of uniform density vaporises due to friction, its mass will go down with the cube of its radius while its cross sectional area will go down with the square of its radius. In other words, as the object vaporises during its descent, the mass decreases proportionally faster than the cross sectional area which helps determines drag. At the same time the atmosphere is getting denser as you approach ground level. The ratio of drag to mass will increase rapidly. Drag will slow the object much faster than it can shed mass. The more mass it sheds, the faster it will slow down anyway.
If you are successful then come back here with those initial conditions and the result and we'll have a look at them and see if they match what we see in the photo.
The only way you can get around this is to propose an object with a near airfoil shape, suitably stabilised with fins or something, possibly with some sort of stratified density distribution, possibly saboted in some manner (with the dense, high mass sabot discarded moments before impact, yet leaving no trace anywhere). Sort of like an armour piercing anti-tank round (see
http://www.fas.org/man/dod-101/sys/land/m829a1.htm).
But smaller, lighter and much MUCH faster.
Doesn't seem likely to me, but that's just an opinion.