"sean" skrev i en meddelelse
om...

snip

I am an interested amateur only, so some of your terminology terms
elude me here. But your post is interesting an informative
thanks.

What conserns Mars, I'm a newbe too

Regarding your last idea of raindrops maybe from a severe and
infrequent storm rather than persistent earth like rainfall ? Although
one problem I thought was if it was rainfall it would have to be a
warm environment and the current climate is way to cold for a liquid
water to fall as rain. Anyways ifthe climate was warm enough and if
the nodules are composed of a material that fuses like a fast drying
cement one could possibly recreate soemthing similar here in a lab. Is
there a gas that liquifies at the present mars temp that could fall as
rain to replace the water part of this precipitate theory?

No, CO2 does not have a liquid fase in the surface temperature/pressure
range. So any application of the idea would take a climatic anomaly away
from the present cold situation.

Otherwise in a dry scenario If the nodules are on the surface maybe
they were created more recently rather than be sediments from wind
action that have since been disturbed.

It's not advisable to do what I did - refere to an instance without a linked
picture. Because the spheres are widespread and have what what seem like
multiple modes or origins - and it confuses the discussion.

http://marsrovers.jpl.nasa.gov/galle...209a/1M1295156
92EFF0312P2939M2M1_mi_RobtE_full-B016R1_br.jpg

This is a detail of the outcrop I refer to

Going back to the explosion
idea I suggested before,..
I dont know if there are enough craters to allow the statistical
chance of finding these all over Mars and at the lander site but I was
thinking a bit more on maybe how they were created, if by an impact
crater event.

I'm a little blank on that

If lets say at impact either water or another gas either present as
liquid or solid in the projectile or in the sediment ,were to be
instantly heated to extreme high tempratures. The material that the
nodules is made of could also mix in that instance with that breif
extremely hot gas cloud above the explosion site sort of like a soupy
particulate mix of gas and liquid droplets mixed with the nodule
element.

I figure that to be the general expectations

As it is forced out and away from the site at great speeds by
the explosion the mixture is cooled rapidly as it spreads out into
the presumabley extreme cold of the martian atmosphere. This would
cause the cloud to precipitate out in a sense into droplets , all
small , and very rapidly `freeze` into shape in seconds as they are
speeding through the extreme sub zero martian atmosphere and then
presumably are hard all consistently sized small frozen droplets when
they land around the impact site. They then over time `freeze dry`
out the liquid water (or whatever liquid it is) in the sun and climate
to the present state of a nodule consisting of just the original
material which could have initialy pre impact have been a powder or
granular material like glass once was sand?

Some seems fragile (atleas to me) others seems to be melted rock - it would
be tempting to unite such a diversity in an impact-event.

One idea would be to look for similar phenomena at old nuclear test
sites as in essense I am suggesting they a sandy or powdery medium
mixed in with a liquid and as baked `nodules in extreme rapid heating
, cooling and speeding `event` through a cold atmosphere to get the
small sized droplet shape. Maybe the thinner matian atmospher would
aerodynamically produce a rounder projectile rather than the heavier
earth atmosphere which would have elongated the droplets .As I
mentioned this phenomena may also occur similarly at nuclear test
sites.

They then erode by wind into the observed sandy mixture

They are observed in diverse places and seems to me to have been produced in
a widespread process and incooperated by different sedimentary processes.
There is a lot of parameters on Mars that differs from Earth - and I think
that most find it surprisingly confusing to puzzle the consequences together
when the desert-surface from a distance afterall looks very Earth-like. I
have in another post tried to let meteorological phenomena be responsible,
but most of the spheres seems too large (to mention one thing) to give such
an idea much credit.
Geochemical considerations may very well hide clues - pressure, temperature,
constituents and complexity should be sufficient to keep everyone at a
distance from even speculating or predicting.

It' a challenging problem.

Carsten