[meteorite-list] Tektites and Meteorites of Terrestrial Origin

From: MexicoDoug_at_aol.com <MexicoDoug_at_meteoritecentral.com>
Date: Sun Jun 4 19:40:54 2006
Message-ID: <316.59b7ad4.31b46968_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
Received on Sun 04 Jun 2006 12:50:48 PM PDT