Jason,
Thank you for responding to my questions. I am also trying to gain a
self-meteoriticized education. I was unaware of the attachment rule.
PS - Attachments aren't supposed to be posted to the list, per list
guidelines - you ask people if they want them and then send out privately...
And if that pic's of a 'Venusian meteorite,' you should head out to Ludlow,
CA, because there's a hell of a big area out there covered in beautiful
desert-varnished basalt - I mean Venusian meteorites - just like that, with
some pieces weighing a good few hundred pounds......downflow from Amboy Crater,
a beautiful cindercone
Unfortunately, I can not head out to Ludlow, CA to see the desert-varnish
basalt, but I can assure you that it is not desert varnish.
Wikipedia definintion of desert varnish
Originally scientists thought that desert varnish was made from substances
drawn out of the rocks it coats. Microscopic and microchemical observations,
however, show that a major part of varnish is clay (which could only arrive by
wind). Clay, then, acts as a substrate to catch additional substances that
chemically react together when the rock reaches high temperatures in the desert
sun. Wetting by dew is also important in the process. The varnish is primarily
composed of particles of clay along with iron and manganese oxides.
Another important characteristic of desert varnish is that it has an
unusually high concentration of manganese. Manganese is relatively rare in the
earth's crust, making up only 0.12% of its weight. In desert varnish, however,
manganese is 50 to 60 times more abundant. This significant enrichment is
thought to be caused by biochemical processes (many species of bacteria use
manganese).
I've already had basic mineralogical testing on my samples. (Remember, I have
been working with the geologists at the National University of Peru). The
mineralogical composition of the fusion crust is identical to the composition
of the matrix. The analysis of the matrix, whole rock, and a cut/slice of the
fusion crust show a very low concentration of Fe and Mn. The actual values are:
Fe 4.93%, Mg 1.48%, Mn .23%, and Ni 69 ppm.
The samples I have and the samples on venusmeteorite.com are not desert
varnish. I know what desert varnish looks like. I've spent a great deal of time
in the desert and have seen many rocks with desert varnish. With the
cooperation of the UNSA geologist, it was ruled-out early in the analysis.
Varnish is additive to the underlying matrix.
One volcanologist said that it may be possible that my samples could be
wind-polished basalt. This is a real possibility that I am currently pursuing
beside the fact that the samples came from a prehistoric alluvial plain and
showed evidence that there was an impact.
Is it possible that a basaltic rock "bubbled up" and subsequently polished by
the wind. Yes, it might be possible. I view it as unlikely due to the extreme
hardness of this particular basalt (>8 mohs), but it is a possibility, and I
will not rule out ANY possibility. He has requested a sample which I will be
sending out when I travel to Lima in the next few weeks.
The extreme hardness of my samples has been puzzling to myself and the
geologists at UNSA. My sample exceeds the natural hardness of basalt. In fact,
it exceeds the hardness of quartz, which is considered to be the hardest
naturally occurring mineral. Quartz hardness is 8.0, and my samples exceed 8.0
on the Mohs scale. Currently, the only known method of creating basalt harder
than quartz is to grind it, apply a special heat treatment at 1300°C where it
re-crystallises, giving it extreme Hardness: 8-9 on the Mohs scale. This
process is known as cast-basalt. Where you would normally expect basalt to
streak on quartz I have a picture showing how quartz streaks on my basaltic
sample and I also have a video of the area showing the natural state
(baby-powder fine sand) If you're interested, I'll send them off-topic.
Best Regards,
Randall
Jason Utas <[EMAIL PROTECTED]> wrote:
Hell, here are a few more of some random ones.
Jason
On 2/15/07, Jason Utas <[EMAIL PROTECTED]> wrote: Here's a pair of pics
of my favorite cratered Sikhote.....
Jason
On 2/15/07, Jason Utas <[EMAIL PROTECTED] > wrote: Hello Randall,
With my self-meteoriticized education, I might be able to help with at least
a few of your questions...
On 2/14/07, Randall Gregory <[EMAIL PROTECTED] > wrote:
Mr. Webb,McCafferty and any interested parties on the list.
If you don't mind, coud you please answer a couple of questions?
Could your Martian impact scenario apply to ejecta from Mercury?
http://www.lpi.usra.edu/meetings/lpsc2003/pdf/1933.pdf
"The spatial density (number per unit volume) of meteoroids varies as a
function of distance from the sun, distance from a planet, ecliptic latitude
and longitude" Are there any projections on the total number of spatial
meteoroids related to planetary volume?
Do meteoroids tend to group or stream? Or are streams and groupings a rare
occurrence?
Excluding space dust, my feelings are that streams and groups would be
predominant.
Depends - if gravity is great enough to draw them together, one would
logically assume that, not only would they group, but they'd tend to come back
together to form a single whole. With 'meteoroids,' however, (the definition
of which tends to mean dust-sized, a stream is much more likely simply because
the gravitational forces between particles are negligible, whereas the solar
wind's push on each is comparatively massive.
Due to a lower escape velocity, would a large asteroid impact on Mercury
close to it's aphelion be more likely to produce ejecta reaching the escape
velocities of Mercury/Sun than a similar event on Venus? Any probability
studies?
Hardly matters - the point is that both are possible.
(For probability, I would assume the best/worst possible conditions:
equatorial launch, launch relative to planetary rotation, lowest daily
temperature range, and rock composition/density (basaltic mass).
Do you know of any studies with respect to meteoroids in space arriving to
earth as meteorites, do they have totally random trajectories due to collisions
or would they generally follow a straight course from their home
asteroid/planet? To put it quite simply, depending on rotation, impact time,
solar orientation, and impact angle could ejecta from a the inner planets
travel in a relatively straight line away from the sun. And would this same
scenario apply to planets outside earth's orbit. Could they travel in a similar
fashion towards Earth? And could this relate to the Earth's orientation to the
sun at the time of meteroite impact. In other words, would outer planet
meteroids be more likely to fall at night and inner planet meteorids fall
during the day.
Is fusion crust thickness directly related to the mineral characteristics of
density, hardness, melting point, thermal conductivity, and internal
tempurature of the meteoroid? Am I wrong in assuming that it is? Are there
other factors?
Of course - though no one's actually studied the topic scientifically, at
least to my knowledge.
Would a shock-heated ejecta upon encountering the extreme cold of space
cause any changes in the density of the underlying material? What about ejecta
at melt temperature?
Cause changes in density how? Of course it would become more dense to a
degree, but most ejected meteorites aren't shock-melted anyways, so this would
have no real effect on the meteorite. Most are simply shocked and have thin
veins of melt.
There are exceptions, and, when dealing with Mercury and Venus, this might be
more likely due to the required increase in the energy of the impactor
(necessary to eject material from these target sources specifically), but this
enters into the realm of pure speculation...
What would be the effect on micrometeorite pitting on various meteoroids?
Negligible. This would have an effect on the top few millimeters of surface
at most, all of which burns off upon entry into the earth's atmosphere. Not
sure where you're going with that...
"Interplanetary dust particles (micro-meteoroids) were expected to form
well-defined craters upon impacting exposed material in space. Studying the
frequency and features of these craters will provide data on the mass-flux
distribution of micro-meteoroids and, to a lesser extent, on the velocity,
magnitude and direction" - Study of Meteoroid Impact Craters on Various
Materials, NASA Langley Research Center.
Yes and no...all of our man-made materials that have been exposed have been
relatively next to earth, a large planetary body - who knows how this would
compare with statistics from bodies exposed to deeper space.
Some of my samples show pitting which may be caused by micro-meteoroid
collisions. Due to the extreme hardness of the sample and sub-millimeter
thickness of the fusion crust these pits have been preserved. The ablated
material gathers on the trailing edge of these pits on orientated samples.
This is very uncommon, and I happen to collect such specimens (Sikhote-Alin
only to date, as I've yet to find any craters on any other meteorites). But
you're forgetting that these aren't true micro-meteoroids - they're pieces of
the meteorite itself that broke off and reimpacted larger fragments in their
last few moments of heated flight.
Regarding 'craters on' Franconia irons, it seems much more likely to me that
these are simply pits caused by the sub-surface vaporization of siliceous
material rather than actual impacting bodies...seeing as they were surrounded
and contain small amounts of the stony material, this seems like a very good
possibility.
Do you know of any meteorites currently in collections that exhibit pitting?
What are the characteristics of the ablated material?
I'll send a picture in a minute, but again, they're not 'micro-meteoroid'
impacts, just impacts of a meteorite into itself, within the earth's
atmosphere. What do you mean by 'ablated material?'
Are all meteorites tested for density and most specifically hardness?
No, meteorites are like terrestrial rocks to a great degree in this respect -
they vary greatly depending on type, and within type classifications
themselves.
And could anyone please help me retrieve this article:
author = {{Blanchard}, M.~B.},
title = "{Artificial Meteor Ablation Studies}",
booktitle = {IAU Colloq. 13: Evolutionary and Physical Properties of
Meteoroids},
year = 1973,
editor = {{Hemenway}, C.~L. and {Millman}, P.~M. and {Cook}, A.~F.},
pages = {241-+},
adsurl = {
http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1973eppm.coll..241B&db_key=AST},
adsnote = {Provided by the Smithsonian/NASA Astrophysics Data System
The closest I've gotten so far is this:
http://ntrs.nasa.gov/search.jsp?R=863979&id=2&qs=No%3D20%26Ne%3D35%26N%3D4294967263%26Ns%3DArchiveName%7C0
You might also look for these:
Blanchard M.B., 1969. Preliminary results of artificial meteor ablation.
Meteoritics 4, 261-261.
Blanchard M.B., 1972. Artificial meteor ablation studies: iron oxides. J.
Geophys Research
77, 2442-2455.
Blanchard M.B., 1972. Artificial meteor ablation studies: iron oxides. J.
Geophys Research
77, 2442-2455.
Blanchard M.B., 1972. Artificial meteor ablation studies: iron oxides. J.
Geophys Research
77, 2442-2455.
Blanchard M.B., 1972. Artificial meteor ablation studies : iron oxides. J.
Geophys Research
77, 2442-2455.
Blanchard Maxwell B., Cunningham Gary G., 1973. Preliminary results of
artificial meteor
ablation of an olivine mineral sample. Meteoritics 8, 15-15.
Blanchard M. B., 1973. Artificial meteor ablation studies . In Hemenway C.L.,
Millman P.M.,
Cook A.F. (eds.): Evolutionary and Physical Properties of Meteoroids.,
N.A.S.A., Wash-
ington D.C. SP-319, 241-254.
Blanchard M B . Cunnmgham G.G., 1974. Artificial meteor ablation studies:
olivine. J.
Geophys. Research 79, 3973-3980.
Blanchard M.B., 1972. Artificial meteor ablation studies: iron oxides. J.
Geophys Research
77, 2442-2455.
Blanchard M.B., 1972. Artificial meteor ablation studies: iron oxides. J.
Geophys Research
77, 2442-2455.
Blanchard M.B., 1972. Artificial meteor ablation studies: iron oxides. J.
Geophys Research
77, 2442-2455.
Or simply browse this....
http://72.14.253.104/search?q=cache:_yuQQphzlJcJ:www.isas.ac.jp/publications/reportSP/no15/6.PDF+Artificial+Meteor+Ablation+Studies+blanchard&hl=en&ct=clnk&cd=13&gl=us
Might find that helpful...no idea. I wasn't able to actually find the
article, but it looks as if it's on record at NASA if you want it badly
enough...the first link I sent.
Regards,
Jason
PS - Attachments aren't supposed to be posted to the list, per list
guidelines - you ask people if they want them and then send out privately...
And if that pic's of a 'Venusian meteorite,' you should head out to Ludlow,
CA, because there's a hell of a big area out there covered in beautiful
desert-varnished basalt - I mean Venusian meteorites - just like that, with
some pieces weighing a good few hundred pounds......downflow from Amboy Crater,
a beautiful cindercone.
Blanchard M.B., 1972. Artificial meteor ablation studies: iron oxides. J.
Geophys Research
77, 2442-2455.
Blanchard M.B., 1972. Artificial meteor ablation studies: iron oxides. J.
Geophys Research
77, 2442-2455.
Randall
Rob,
I was wondering if there would there be any ablation at all on the outbound
martian rock, from a planet with:
Surface atmospheric pressure: ~6.1 mb (about 1/150th that of Earth's)
Surface gas density: ~0.020 kg/m3
Surface temperature: ~210 K (-63 degrees Celsius)
Low escape velocity
And is it possible to achieve such a low impact angle or would gravity and
aerodynamic drag increase the angle so that a 1-3 degree trajectory may not be
possible. I believe existing ballistic models could be combined with a Mars
atmosphere model and gravitational model that might help to answer this
question.
Quite possibly a composite mathematical model borrowing code from the many
existing models might add validity to your theory. I believe Mars atmosphere
models, ballistic, compression, heating, and the myriad are all fairly
constant. It might not be such a large undertaking to help determine if a
lightly shocked rock could be back-spinned into space. I'd really like to see a
model like this applied to the other planets such as Mercury.
Would anyone like to start a project on this?
In your estimation, could one determine what the minimum energy values are
needed for this event to occur? And could this model be applied to Mercury? ;)
Randall
Rob McCafferty <[EMAIL PROTECTED]> wrote:
--- "Sterling K. Webb"
wrote:
> [I have a theory, of course, but not room enough
> in this margin to write it down.]
>
I believe Fermat wrote something the same thing and it
took nearly 300 years to prove it. Sterling, make a
mental note to ACTUALLY write the theory down to save
some poor sucker from having to write a 200page thesis
in the future.
Would not Martian ablation on the way out from Mars
simply be destroyed by terrestrial ablation on the way
in to us? You know how much of the meteorites are
removed by the process. I find it difficult to believe
any could survive.
I often thought that rock could escape it's host
planet through the rarefaction zone above the
impactors trajectory. However, how this tallies with
low shock levels I don't know.
As I understand, the low shock would need to be right
at the very edge of the impact site. Not ideal for
launching up into a rarefaction zone. ...
Unless, {and here's a wild guess that's probably WAAAY
off but I'll accept criticism with dignity, only a
little sobbing and wailing}...
Could a low angle impact [1-3degrees] produce
sufficient rarefaction befind it to allow the low
shocked rock at the trailing edge of the impact site
to be 'grazed off' in a backward direction, back up
the initial path of the impactor?
Rob McC
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