"Sir Charles W. Shults III" skrev i en
meddelelse ...
I've just looked at the Sol 27 panoramics for Opportunity, and it is
very clear to me that these are indeed sedimentary rocks.
A simple
explanation would be that the spheres are the fossils of some simple
organism, that upon dying, would drop to the bottom and be buried in the
same manner that fossils here on Earth can be trapped in layers of
sediment.
You can clearly see that the spheres are trapped in the layers, and
that
they are eroding out. The least hypothesis is that the spheres were
deposited in the layers as the layers were forming. They are more durable
than the layers themselves, which is easy to see in the weathering images
from the microscope.
Furthermore, the spheres themselves show some characteristics that are
otherwise extremely difficult to explain using standard geological
processes. As a long time amateur rockhound, I have seen and collected
many
specimens, both abiotic and fossils. I could easily understand a sphere
with consistent layering throughout, but not many spheres with similar
markings such as parallel grooves or chevrons.
I have compiled the microscopic images and performed some contrast and
image processing to extract features that are otherwise faint or difficult
to discern, and there are definitely common features on many of the
spheres.
In my (perhaps flawed but experienced) opinion, we are seeing fossils.
There, it's been said.
I have a good reason to take this position- in 1992, I wrote an
article
about the possibility of life on Mars (which was published in Astrolog
magazine), and used some of the reasoning of Thomas Gold about petroleum
formation and organisms that metabolize petroleum.
In it, I predicted that organisms could still be extant in the rock of
Mars if it consumed petroleum as many such organisms here on Earth do.

I think that you have forgot that petroleum is a product of decaying organic
material and that such material - though abundant on Earth - for good
reasons has not (to my knowledge) been found on Mars.

Also, I predicted that in that case, we should look for fine grained
magnetite, which is a metabolic byproduct of the digestion process of
those
sorts of organisms.

Metane-metabolizing organisms 'breath' in a oxygen-deficient environment and
makes it even more so. To expect an oxidized ironcompound in such an
environment does not make sense to me.

This was four years before the flap about ALH84001 (1996) so in a
sense
I beat them to press with at least two good predictions that matched what
they found.
At this point, I am very encouraged by what we are seeing that life
did
indeed exist on Mars, and that if we were to bore deeply into the rocks
where petroleum might exist,

It would be a really big surprise to find oil

we would discover that deep inside the planet,
there are still organisms that are alive and well.
After all, a loss of atmosphere here on Earth would not destroy those
organisms that live within the rock.

I'm not a biologist, but I'm under the impression that we talk bacteria with
cells. That is something that most Earth-organisms share and is believed to
origin in a sea. A wet past on Mars is not obvious (though present) and life
there would in my (not very skilled) opinion have had every chance to evolve
in a profoundly different path than on Earth. So basically I do not
preclude Mars 'life' but that it should be on a sub-bacterial level with a
sphere as a 'random' shape not expressing a cluster of symbiotic organisms
that produces a uniform shape with grooves etc. There is in my opinion a lot
of untested possibilities for a mineralogical origin - but chemistry too is
very different from Earth-conditions, and complex enough make plenty of room
for ideas that is not biological. Thinking chemistry in terms of
bio-chemistry is natural on Earth becaurse every little creture is involved
in chemistry and that a majority of geological processes in Earth
sedimentation involvs their work.

I intend to post these processed images on my website shortly, as this
is a very interesting development and it is good, reasonable support for
this idea.
Once again, I am not a geologist, but I am a scientist and have been a
rock collector for about 40 years. My opinions could be completely wrong,
but I believe that Opportunity has succeeded in finding remnants of
extinct
Martian organisms.

You would probably have to look further back in time to find suitable
Earth-derived 'organisms' to compare to Mars conditions - and there is not
much to look at so far back.

Carsten