This chemical will
oxidize the LR compounds to produce CO2. However relatively
strong concentrations (approximately 2%) of H2O2 are
required to emulate the amplitude and kinetics of the LR Mars positive
responses. The most significant fact countering the
H2O2 theory is that H2O2 and
any of its proposed derivatives do not approximate the thermal sensitivity
of the martian agent causing the LR responses. At 50░C, 90%
H2O2 decomposes at only 0.001% per
hour39. Of numerous attempts to simulate those results with
H2O2, none reported has succeeded under conditions
consistent with those on Mars. H2O2, highly
sensitive to destruction by solar UV, has an expected lifetime in the
martian atmosphere of less than one day. Any deposition of
H2O2 from the atmosphere to the soil is likely too
small to account for the LR results40. Based on the UV lability
of H2O2, it is difficult for it to account for the
LR activity. In addition, experiments41,42 reporting the
formation of organic matter from simulated sun-irradiated martian
atmosphere demonstrated that the organic matter accumulated despite the
continuous incidence of the UV light. Evidently, the
H2O2 formed under these simulated martian conditions
was not made in sufficient quantity or did not survive the UV to oxidize
the organic matter as fast as it was synthesized. The lifetime of
H2O2 would be further reduced by the catalytic
effects of y-Fe2O3 reported43 as likely
to be extensive on Mars.
The re-examination of the Mars PR data also has
repercussions for the H2O2 theories. The theories
propose that there is oxidant in the soil. Why did that oxidant not
destroy the organics formed and detected within the PR?
A variant chemical model proposing UV formation of
peroxonitrites44 in the soil has been proposed since the review
cited above. Aside from its failure to explain the result in the sample
taken under the rock, this theory has not demonstrated the thermal
sensitivity of the agent detected by the LR. Also, the formation of
peroxonitrites would require amounts of nitrogen in the Mars soil in
excess of the limit set by the Viking elemental
analysis45.
A general question about attributing the failure to
find organics on Mars to peroxide is the finding46 of
H2O2 in ancient permafrost cores on Earth, where the
oxidant did not eliminate organic matter or life. Being nearer to the sun
and having more water vapor than Mars does in its upper atmosphere, Earth
experiences the formation of H2O2 in amounts greater
than does Mars. Yet, H2O2 was not inimicable to the
development of life and the accretion of organic matter on Earth. Life
developed enzymes to protect against this oxidant, and many species came
to utilize it in their energy-producing metabolic processes.
3. No Liquid Water; Extreme Environment: Next
to the peroxide theories, the most vigorous defense of the chemical nature
of the LR results stems from the beliefs that all life must have access to
water in liquid form and that none is available on the surface of Mars.
Moreover, it has been stated47 that the atmospheric pressure at
the surface of Mars is below the triple point of water and likely has been
so for several billion years. This is not supported by data obtained by
the Infrared Interferometer Spectrometer (IRIS) experiment48
aboard the Mariner 9 Mars orbiter. It reported that "Extensive regions
have been found where the surface pressure exceeds the triple-point
pressure of water" and that "under temperature conditions which frequently
occur on Mars, liquid water can exist in equilibrium with its vapor." A
recent publication49 of Viking data provides a graph, FIG. 2,
showing that, over a full martian year, the surface atmospheric pressures
at both Viking landing sites continuously exceeded the triple point
pressure for water. Further, inspection of the Viking data
shows50 that the temperature of the top several millimeters of
soil beneath the Viking Lander 2 sampling head rose to 273░K (the
temperature at which ice liquifies) where it remained for at least several
minutes. This is evidence for the melting of ice into liquid water. The
thermal absorption of the metallic sampling head may have been
responsible, but its thermal adsorption is likely equaled, or exceeded, by
that of martian rocks. Surface temperatures in the southern latitudes at
the start of summer were seen to exceed 273░K for several hours per day.
Thermal inertias for large areas of Mars range above 6, and above 30 for
bare rocks. Albedos of unfrosted martian ground are as low as
0.095.51 Viking orbital data52 also support the
presence of liquid water in the upper few millimeters of the martian
surface.
