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Posted by baalke on July 31, 2006, 7:41 pm
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http://www.berkeley.edu/news/media/releases/2006/07/31_peroxide.shtml
Mars' dust storms may produce peroxide snow
Robert Sanders
UC Berkeley Press Release
31 July 2006
BERKELEY - The planet-wide dust storms that periodically cloak Mars in
a
mantle of red may be generating a snow of corrosive chemicals,
including
hydrogen peroxide, that would be toxic to life, according to two new
studies published in the most recent issue of the journal Astrobiology.
Based on field studies on Earth, laboratory experiments and theoretical
modeling, the researchers argue that oxidizing chemicals could be
produced by the static electricity generated in the swirling dust
clouds
that often obscure the surface for months, said University of
California, Berkeley, physicist Gregory T. Delory, first author of one
of the papers. If these chemicals have been produced regularly over the
last 3 billion years, when Mars has presumably been dry and dusty, the
accumulated peroxide in the surface soil could have built to levels
that
would kill "life as we know it," he said.
"If true, this very much affects the interpretation of soil
measurements
made by the Viking landers in the 1970s," said Delory, a senior fellow
at UC Berkeley's Space Sciences Laboratory. A major goal of the Viking
mission, comprised of two spacecraft launched by NASA in 1975, was
testing Mars' red soil for signs of life. In 1976, the two landers
aboard the spacecraft settled on the Martian surface and conducted four
separate tests, including some that involved adding nutrients and water
to the dirt and sniffing for gas production, which could be a telltale
sign of living microorganisms.
The tests were inconclusive because gases were produced only briefly,
and other instruments found no traces of organic materials that would
be
expected if life were present. These results are more indicative of a
chemical reaction than the presence of life, Delory said.
"The jury is still out on whether there is life on Mars, but it's clear
that Mars has very chemically reactive conditions in the soil," he
said.
"It is possible there could be long-term corrosive effects that would
impact crews and equipment due to oxidants in the Martian soil and
dust."
All in all, he said, "the intense ultraviolet exposure, the low
temperatures, the lack of water and the oxidants in the soil would make
it difficult for any microbe to survive on Mars."
The article by Delory and his colleagues appearing in the June issue of
Astrobiology demonstrates that the electrical fields generated in
storms
and smaller tornadoes, called dust devils, could split carbon dioxide
and water molecules apart, allowing them to recombine as hydrogen
peroxide or more complicated superoxides. All of these oxidants react
readily with and destroy other molecules, including organic molecules
that are associated with life.
A second paper, coauthored by Delory, demonstrates that these oxidants
could form and reach such concentrations near the ground during a storm
that they would condense into falling snow, contaminating the top
layers
of soil. According to lead author Sushil K. Atreya of the Department of
Atmospheric, Oceanic, and Space Sciences at the University of Michigan,
the superoxidants not only could destroy organic material on Mars, but
accelerate the loss of methane from the atmosphere.
Coauthors of the two papers are from NASA Goddard Space Flight Center;
the University of Michigan; Duke University; the University of Alaska,
Fairbanks; the SETI Institute; Southwest Research Institute; the
University of Washington, Seattle; and the University of Bristol in
England.
Delory and his colleagues have been studying dust devils in the
American
Southwest to understand how electricity is produced in such storms and
how the electric fields would affect molecules in the air - in
particular, molecules like those in the thin Martian atmosphere.
"We are trying to look at the features that make a planet habitable or
uninhabitable, whether for life that developed there or for life we
bring there," he said.
Based on these studies, he and his colleagues used plasma physics
models
to understand how dust particles rubbing against one other during a
storm become positively and negatively charged, much the way static
electricity builds up when we walk across a carpet, or electricity
builds in thunderclouds. Though there's no evidence for lightning
discharges on Mars, the electric field generated when charged particles
separate in a dust storm could accelerate electrons to speeds
sufficient
to knock molecules apart, Delory and his colleagues found.
"From our field work, we know that strong electric fields are generated
by dust storms on Earth. Also, laboratory experiments and theoretical
studies indicate that conditions in the Martian atmosphere should
produce strong electric fields during dust storms there as well," said
co-author Dr. William Farrell of NASA's Goddard Space Flight Center in
Greenbelt, Md.
Since water vapor and carbon dioxide are the most prevalent molecules
in
the Martian atmosphere, the most likely ions to form are hydrogen,
hydroxyl (OH) and carbon monoxide (CO). One product of their
recombination, according to the second study, would be hydrogen
peroxide
(H2O2). At high enough concentrations, the peroxide would condense into
a solid and fall out of the air.
If this scenario has played out on Mars for much of its history, the
accumulated peroxide in the soil could have fooled the Viking
experiments looking for life. While the Labeled Release and the Gas
Exchange experiments on the landers detected gas when water and
nutrients were added to Martian soil, the landers' Mass Spectrometer
experiment found no organic matter.
At the time, researchers suggested that very reactive compounds in the
soil, perhaps hydrogen peroxide or ozone, could have produced the
measurements, imitating the response of living organisms. Others
suggested a possible source for these oxidants: chemical reactions in
the atmosphere catalyzed by ultraviolet light from the sun, which is
more intense because of Mars' thin atmosphere. The predicted levels
were
far lower than needed to produce the Viking results, however.
Production of oxidants by dust storms and dust devils, which seem to be
common on Mars, would be sufficient to cause the Viking observations,
Delory said. Thirty years ago, some researchers considered the
possibility that dust storms might be electrically active, like Earth's
thunderstorms, and that these storms might be a source of the new
reactive chemistry. But this had been untestable until now.
"The presence of peroxide may explain the quandary we have had with
Mars, but there is still a lot we don't understand about the chemistry
of the atmosphere and soils of the planet," he said.
The theory could be tested further by an electric field sensor working
in tandem with an atmospheric chemistry system on a future Mars rover
or
lander, according to the team members.
The team includes Delory, Atreya, Farrell, and Nilton Renno & Ah-San
Wong of the University of Michigan; Steven Cummer of Duke University,
Durham, N.C.; Davis Sentman of the University of Alaska; John Marshall
of the SETI Institute in Mountain View, Calif.; Scot Rafkin of the
Southwest Research Institute in San Antonio, Texas; and David Catling
of
the University of Washington.
The research was funded by NASA's Mars Fundamental Research Program and
by NASA Goddard internal institutional funds.
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Posted by Thomas Lee Elifritz on July 31, 2006, 7:46 pm
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baalke@earthlink.net wrote:
> http://www.berkeley.edu/news/media/releases/2006/07/31_peroxide.shtml
>
> Mars' dust storms may produce peroxide snow
> Robert Sanders
> UC Berkeley Press Release
> 31 July 2006
>
> BERKELEY - The planet-wide dust storms that periodically cloak Mars in
> a
> mantle of red may be generating a snow of corrosive chemicals,
> including
> hydrogen peroxide, that would be toxic to life, according to two new
> studies published in the most recent issue of the journal Astrobiology.
So the whole Mars Landing thing is off then.
Bush and Griffin are gonna be crushed when they find that out.
Oh well ... lets return to the moon! At least we know how to do that.
Er ... don't we?
http://cosmic.lifeform.org
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Posted by Jan Panteltje on August 1, 2006, 7:17 am
Please log in for more thread options On a sunny day (Mon, 31 Jul 2006 18:46:12 -0500) it happened Thomas Lee
>baalke@earthlink.net wrote:
>
>> http://www.berkeley.edu/news/media/releases/2006/07/31_peroxide.shtml
>>
>> Mars' dust storms may produce peroxide snow
>> Robert Sanders
>> UC Berkeley Press Release
>> 31 July 2006
>>
>> BERKELEY - The planet-wide dust storms that periodically cloak Mars in
>> a
>> mantle of red may be generating a snow of corrosive chemicals,
>> including
>> hydrogen peroxide, that would be toxic to life, according to two new
>> studies published in the most recent issue of the journal Astrobiology.
>
>So the whole Mars Landing thing is off then.
There idea makes no sense, spectra taken do not reveal any of that stuff.
The Viking experiments were 'short lived; because heating the soil killed
the life.
>Bush and Griffin are gonna be crushed when they find that out.
>
>Oh well ... lets return to the moon! At least we know how to do that.
>
>Er ... don't we?
The biggest disaster for the US would be if the next 3 moonlandings failed...
>http://cosmic.lifeform.org
I expect Chinese restaurants, Japanese Sony shops, and Italian pizza stands
to awat to refresh the first yankee martionauts.
They should bring enough Russian currency.
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Posted by George on August 1, 2006, 3:00 pm
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> On a sunny day (Mon, 31 Jul 2006 18:46:12 -0500) it happened Thomas Lee
>
>>baalke@earthlink.net wrote:
>>
>>> http://www.berkeley.edu/news/media/releases/2006/07/31_peroxide.shtml
>>>
>>> Mars' dust storms may produce peroxide snow
>>> Robert Sanders
>>> UC Berkeley Press Release
>>> 31 July 2006
>>>
>>> BERKELEY - The planet-wide dust storms that periodically cloak Mars in
>>> a
>>> mantle of red may be generating a snow of corrosive chemicals,
>>> including
>>> hydrogen peroxide, that would be toxic to life, according to two new
>>> studies published in the most recent issue of the journal Astrobiology.
>>
>>So the whole Mars Landing thing is off then.
>
> There idea makes no sense, spectra taken do not reveal any of that stuff.
>
> The Viking experiments were 'short lived; because heating the soil killed
> the life.
Umm, heating killed off life that wasn't known to be their prior to the
heating? If it wasn't known prior to the heating, why do you now claim
that it was killed by the heating. And you do realize that even a steak
cooked on a grill leaves evidence for its prior existence, right? Jeez.
Where do these people come from?
George
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Posted by Aidan Karley on August 1, 2006, 9:02 pm
Please log in for more thread options > The Viking experiments were 'short lived; because heating the soil killed
> the life.
>
The Viking experiments were designed to *distinguish* between chemical
reactions in the soil samples and biological reactions in the soil. Since two
scoops of soil may not contain exactly the same chemistry and grain sizes,
then they achieved this by incubating the soil samples, then baking the soil
to kill of any LJBAWKI ("life, Jim, but not(not) as we know it") and
re-incubating to see if there was a differential response.
Unfortunately, such a methodology would be susceptible to
thermo-labile reactivity as the original authors suggest.
The comparable situation in joke-universe would be the man who works
as a tester in the RedNeck Match Company - "This match works ... this one
works ... this one works."
> I expect Chinese restaurants, Japanese Sony shops, and Italian pizza stands
> to awat to refresh the first yankee martionauts.
> They should bring enough Russian currency.
>
Arenauts?
In the more civilised parts of Russia, Euros are as easily accepted as
USD, and pretty much as often seen. Still not particularly common, but that's
changing, and the change is accelerating.
--
Aidan Karley, FGS
Aberdeen, Scotland
Written at Tue, 01 Aug 2006 23:26 +0100, but posted later.
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