Mars rover meteorite find

Opportunity has found a second big iron meteorite:
http://spaceflightnow.com/news/n0910/11meteorite/
What's odd about this story?
Mars is supposed to have all this subsurface ice, right?
If you put a block of iron onto ice, it will slowly start to sink into
it over a period of time, as anyone who has had a snow shovel frozen to
the ground in winter knows.
In three billion years, you would have thought the meteorite would have
sunk into that hypothetical ice.
I also think that that dating came right out of (forgive the pun) thin
air, as they have no way of knowing how old it is without some pretty
involved lab tests involving isotopic content.
Besides which, on Earth iron meteorites corrode away over time when
exposed to liquid water.
If their age statement is correct, then Mars has been free from rain for
three billion years, which blows the whole ancient "Wet Mars" theory
completely apart.

Pat

"Pat Flannery" wrote in message
lephone...
Opportunity has found a second big iron meteorite:
http://spaceflightnow.com/news/n0910/11meteorite/
What's odd about this story?
Mars is supposed to have all this subsurface ice, right?
If you put a block of iron onto ice, it will slowly start to sink into it over
a period of time, as anyone who has had a snow shovel frozen to the ground in
winter knows.


Meridiani is a huge sheet of sedimentary rock, covered by a foot or
two of soil and dust. It shouldn't sink past the layer of sedimentary
rock., which Btu is highly cracked from freeze and thawing.
Allowing an excellent geology for holding near surface underground
ice. And if you look at the horizon, it obvious such a perfectly flat
surface must be the result of a body of water or ice. Meridian
has probably spent much of it's history covered in an ice sheet
which waxes and wanes with the Martian ice ages.

Imagine searching for meteorites in the Antarctic without the ice.
Should be a great place to look for them.
http://areo.info/mer/opportunity/118...L2L5L5L6L6.jpg
http://areo.info/mer/opportunity/117...5L6L6.jpg.html


"More than 10,000 meteorite specimens have been recovered in Antarctica since
annual meteorite expeditions began in 1976. According to the NSF, the region
is one of the best places on Earth to search for meteorites for two reasons.
Firstly, while meteorites fall all over the globe they are much easier to spot
if the background material is light-colored and plain - like ice. Secondly,
there are few terrestrial rocks along the Antarctica plain to complicate the
search."
http://antarctica.computerworld.com....10&fp=4&fpid=2


Meridiani has virtually no rocks at all, of any size. Another huge clue to it's
wet past. Just a field of spheres as far as the eye can see, and handfuls of
cobbles.
http://areo.info/mer/opportunity/060...5L6L6.jpg.html





In three billion years, you would have thought the meteorite would have sunk
into that hypothetical ice.
I also think that that dating came right out of (forgive the pun) thin air, as
they have no way of knowing how old it is without some pretty involved lab
tests involving isotopic content.
Besides which, on Earth iron meteorites corrode away over time when exposed to
liquid water.
If their age statement is correct, then Mars has been free from rain for three
billion years, which blows the whole ancient "Wet Mars" theory completely
apart.


There's plenty of evidence of underground water ice.

40th Lunar and Planetary Science Conference (2009)
March 24, 2009
POSTER SESSION I: MARS NEAR-SURFACE ICE
http://www.lpi.usra.edu/meetings/lps...df/sess319.pdf


Thursday, March 26, 2009
MARS: AQUEOUS PROCESSES
http://www.lpi.usra.edu/meetings/lps...df/sess501.pdf



Program
40th LUNAR AND PLANETARY SCIENCE CONFERENCE
March 23-27, 2009
http://www.lpi.usra.edu/meetings/lps...df/program.pdf


Pat

Pat Flannery wrote:

Besides which, on Earth iron meteorites corrode away over time when
exposed to liquid water.

In the presence of Oxygen.

Sylvia.

Sylvia Else wrote:
Pat Flannery wrote:

Besides which, on Earth iron meteorites corrode away over time when
exposed to liquid water.

In the presence of Oxygen.


I hate to tell you this, but water is partially made of oxygen.
That's why sunken ships rust away, even at great depths where there is
very little oxygen content in the water.
Now, you could make a argument that the nickel content of the meteorite
turned it into what was effectively stainless steel, but the ones found
buried here on Earth have a lot of rust surrounding them.
And aqueous corrosion does indeed occur on Mars:
http://gsa.confex.com/gsa/2009NC/fin...act_156196.htm

Pat

Pat Flannery wrote:
Sylvia Else wrote:
Pat Flannery wrote:

Besides which, on Earth iron meteorites corrode away over time when
exposed to liquid water.

In the presence of Oxygen.


I hate to tell you this, but water is partially made of oxygen.

Well it's not that simple. It takes more than just water, despite its
oxygen content. However I note that carbon dioxide in the presence of
water will allow iron to rust, and there's certainly carbon dioxide there.

That's why sunken ships rust away, even at great depths where there is
very little oxygen content in the water.

They rust rather slowly. There is also a biological involvement.

Now, you could make a argument that the nickel content of the meteorite
turned it into what was effectively stainless steel, but the ones found
buried here on Earth have a lot of rust surrounding them.
And aqueous corrosion does indeed occur on Mars:
http://gsa.confex.com/gsa/2009NC/fin...act_156196.htm

Doesn't appear to say anything relevant. No mention of rust. Indeed, it
rather seems to be discussing the solvent effects of water.

Sylvia.

Pat Flannery wrote:
Opportunity has found a second big iron meteorite:
http://spaceflightnow.com/news/n0910/11meteorite/
What's odd about this story?
Mars is supposed to have all this subsurface ice, right?
If you put a block of iron onto ice, it will slowly start to sink into
it over a period of time, as anyone who has had a snow shovel frozen to
the ground in winter knows.
In three billion years, you would have thought the meteorite would have
sunk into that hypothetical ice.
I also think that that dating came right out of (forgive the pun) thin
air, as they have no way of knowing how old it is without some pretty
involved lab tests involving isotopic content.
Besides which, on Earth iron meteorites corrode away over time when
exposed to liquid water.
If their age statement is correct, then Mars has been free from rain for
three billion years, which blows the whole ancient "Wet Mars" theory
completely apart.

Pat

From the article it appears the dating is based on the fact that the
meteorites managed to land intact, and without creating large craters.
The implication is that they landed when Mars had a thicker atmosphere
than it does now. While the 3 billion number may look overly precise,
the event could hardly be geologically recent unless you can find a
mechanism that would have recently thinned Mars's atmosphere.

Sylvia.

"Sylvia Else" wrote in message
...
Pat Flannery wrote:
Opportunity has found a second big iron meteorite:
http://spaceflightnow.com/news/n0910/11meteorite/
What's odd about this story?
Mars is supposed to have all this subsurface ice, right?
If you put a block of iron onto ice, it will slowly start to sink into it
over a period of time, as anyone who has had a snow shovel frozen to the
ground in winter knows.
In three billion years, you would have thought the meteorite would have sunk
into that hypothetical ice.
I also think that that dating came right out of (forgive the pun) thin air,
as they have no way of knowing how old it is without some pretty involved lab
tests involving isotopic content.
Besides which, on Earth iron meteorites corrode away over time when exposed
to liquid water.
If their age statement is correct, then Mars has been free from rain for
three billion years, which blows the whole ancient "Wet Mars" theory
completely apart.

Pat




From the article it appears the dating is based on the fact that the
meteorites managed to land intact, and without creating large craters.

Take a good look at the horizon at Meridiani, only a body of water or
ice sheet can create a ...perfectly flat...horizon in all directions.
The assumptions concerning cratering are erroneous.
There's a reason the Rover team named the features on
Meridiani's Endurance 'Crater' ...bays and capes.
Because it's not an impact crater, it was a lake.



The implication is that they landed when Mars had a thicker atmosphere than it
does now. While the 3 billion number may look overly precise, the event could
hardly be geologically recent unless you can find a mechanism that would have
recently thinned Mars's atmosphere.


Mars has ice-ages. To think the planet died 3 billion years ago doesn't
agree with observation. And btw much of the entire surface, especially
all of Meridiani is coated with a thin sheet of iron deposits. The spheres
are some half iron. Why is all that iron still sitting there, nice and pretty
right on the surface? It's the reason the planet is red. Either the climate
doesn't reduce iron very well or there's a mechanism that constantly
replenishes the iron.

On Earth, anomalous concentrations of iron are almost ...always..the
result of microbial activity.




Sylvia.

I forgot to provide the links in the post above.


Take a good look at the horizon at Meridiani, only a body of water or
ice sheet can create a ...perfectly flat...horizon in all directions.
The assumptions concerning cratering are erroneous.
There's a reason the Rover team named the features on
Meridiani's Endurance 'Crater' ...bays and capes.
Because it's not an impact crater, it was a lake.
It may have started out as a small crater, but greately
expanded due to water erosion. Look at how the surface
of Meridiani...drapes...the crater wall. Showing it subsided.


http://areo.info/mer/opportunity/118...L2L5L5L6L6.jpg
http://areo.info/mer/opportunity/117...5L6L6.jpg.html

Sylvia Else wrote:

From the article it appears the dating is based on the fact that the
meteorites managed to land intact, and without creating large craters.
The implication is that they landed when Mars had a thicker atmosphere
than it does now. While the 3 billion number may look overly precise,
the event could hardly be geologically recent unless you can find a
mechanism that would have recently thinned Mars's atmosphere.

One person commenting on it had a interesting theory that neatly
explained both why it survived entry and why it's just sitting around
intact on the surface, rather than having made a crater; they suggested
that the meteorite had landed on either water or CO2 ice which had later
sublimated into the Martian atmosphere, in a process similar to the way
Antarctic meteorites are found sitting on the ground at the base of
melting glaciers.
Given that the Martian axis of rotation has apparently wandered all over
the place in its past due to the lack of a large moon to keep its poles
stable in relation to the planet's surface in the way Earth's moon does,
the meteorite may have fallen onto one of the polar caps, only to have
the pole migrate away from under it as time passed, leaving it sitting
on bare ground. Snow and ice (water or CO2) could have cushioned the
impact enough to prevent it from breaking up on impact even at low
atmospheric pressures.
Another interesting thought is that instead of falling in from deep
space, the meteorite may have decayed out of Martian orbit, as several
ovoid craters on the Martian surface are thought to be the impact points
of small decaying Martian moonlets (impactors have to hit at a very
shallow angle to create anything other than a circular crater) and it is
suspected that in another 50 million years Phobos is going to come
flying out of the Martian sky also.

Pat