[meteorite-list] Tektites and Meteorites of Terrestrial Origin

[MexicoDoug at aol.com]

Rob M. wrote:

>How do the orbital  dynamics work. Can something
>achieve escape velocity only to come back  later? I
>think there are enough mechanisms in place to allow  it.

>in the car today (no radio since i put my car in a ditch  
>upside down a few moths back. My car is my think time)

Rob and  friends,

This is a hard question since it is in the Tounelan realm of  mullings: no 
hard scientific evidence to study at the moment.  Thus it is  quite theoretical 
to put it kindly.

First, I would think about how many  meteorites we have seen that retain any 
cosmic velocity upon impacting the  earth's surface.  I would think carefully 
about this as I lamented not  being able to listen to the eeriely classical 
Finnish piece by Sibelius, the  Swan of Tounela, in my missing car stereo 
comparing visions of the Swan  incessently circling to the possibility of myself 
finding contemporary meteorite  fragments, as opposed to Lemminkainen's turning 
sand into pearls as he hunted  down the innocent Swan.

After hunting the sacred and exquisite, dark  tektite-colored Swan, and 
thinking I could have succeeded where the Gods have  failed, I would then be washed 
up motionless upon the shores and wait for my  mother's vitreous celestial 
tears to fall on my forehead to re-enbody my flesh  and spirit.

Earth's atmosphere's stresses are inverted vs. the meteorite,  for the 
tektite's trajectory upon leaving the planet's surface.  We know  that meteorites 
explode at shear frictional forces over 10 kilometers high, so  we should expect 
clearly at ground level a formation of a motley minutiae of  small fragments 
of each and every candidate escape-bolder.  Upon breakup,  that fragment's 
surface area to mass ratio changes drastically, and does it  surprise us that the 
velocity is damped and the energy all converted into a bit  of fracture 
energy and a lot of frictional energy (a favorite physics lab  experiment is to 
shake a jar or sand abd measure the increase in temperature -  now imagine that 
the friction is a stone wall of an atmosphere.  Inverting  the order of the 
trajectory is like trying to catch a person from a very tall  burning building by 
telling them to jump because you have put a bed several  meters under the 
concrete that they will hit first...I wouldn't expect them to  survve that fall...

Later, I'd Google to find what percentage of the  surface of the earth was 
silicated and look at the Nordlinger Ries crater source  rock and see if the 
perceived absense of other minerals made sense given this  source rock.  Then I'd 
look at the other tektites with proven  craters.  It should make sense or 
else how would they have been linked  (source rock to tektite) in the first place?

On top of that, before  considering 'orbital dynamics' I would consider the 
energy required for  achieving the threshold velocity to touch space from 
Earth, even if it is only  to 100 km up, and then fall right back down.  I would do 
it for a full  atmosphere of gas and thus need a handle on friction and 
constrain my  calculations to time during which the glass remains plastic on the 
way up - then  convert this energy for the gamut of tektite sizes and ask, now 
does it make  sense that the temperature has to be so hot as to melt them  
completely?

Then I would consider that the aerodynamic forms exhibited by  tektites 
require it to have been a very fast and continuous event, since they  are found in 
well defined strewn fields, and not randomly or at inconsistent  *large* 
distances on Earth's surface.

I have no doubt the answer would be  yes for all these lame attempts to shed 
some light on this.  Arguments for  plasma formation, reverse jets, while 
founded, don't matter much for your  question, as the collision induced 
temperatures and pressures for those specific  parts of the impact melt clearly wouldn't 
produce contemporary meteoritesof the  type of the omnipresent 1000 on eBay.  
Theoretically speaking, of course. I  haven't done the above calculations so 
we stay on the comfortable level of  mullings.

Saludos, Doug