While the actual data
were not presented, it was stated that the spectrum showed "weak bands in
the 2850-3000 cm-1 characteristic of the C-H stretch of
methylene groups (-CH2-). Consistent with this, (the) C2 (fraction) gave
hydrocarbon fragments on pyrolysis and showed aliphatic (sp3)
carbon in its 13C CP-MAS NMR spectrum." Thus, organic compounds
surviving this rugged digestion were detected in the soil. They were
attributed to kerogen and coal refractory to the GCMS pyrolysis.
Biological possibilities were discounted although viable microorganisms
have been reported23 within anthracite coal taken from deep
underground. The purpose of the intensive digestion of the Antarctic #726
was not stated. One must wonder what variety of labile organic compounds
were present prior to the digestion.
When asked how the report of organic matter in
ALH84001 could be reconciled with the negative results of the Viking GCMS,
a NASA spokesman24 said that the GCMS had been sent to Mars
long ago and may not have been sensitive enough to detect the amounts of
organic matter in the low microorganism population in the meteorite. The
Viking GCMS was reported25 to require organic content
equivalent to 106 bacterial cells to obtain a response in its
100 mg soil sample. This is in sharp contrast to the 50-cell sensitivity
of the LR. The difference in sensitivities can readily explain the
disparate results reported by the two instruments.
A fresh examination of the Viking Pyrolytic Release
Experiment (PR) data26 supplies direct support for the
formation and persistence of organic matter on Mars. In the experiment, a
sample of soil is taken into a chamber containing simulated martian
atmosphere with its CO and CO2 labeled with 14C. The sample is
then exposed to simulated martian sunlight to permit any phototrophic
microorganisms to photosynthesize and incorporate the label. After an
incubation period, the non-incorporated gases are exhausted from the
chamber, and the sample is pyrolyzed to release any labeled gas that had
been fixed by the microorganisms. The detection of the gas released by the
pyrolysis step is evidence for life.
During the development of the PR instrument, the
formation and accumulation of organic matter from CO and CO2
split by the UV of the simulated sunlight posed the serious threat of
obtaining a false positive on Mars. The experimenters reported, "About 14
nmoles of 14C organics per gram of volcanic ash shale are
formed within 70 hours of irradiation under a realistic simulation of
martian conditions."27 This formation of organic matter from
simulated martian atmosphere under simulated sunlight was independently
confirmed28. The "solution" to the PR false positive problem
was to incorporate an optical filter to screen out the UV below 320
nm.
In its first experiment on Mars, the PR produced a net
response of 81 cpm upon pyrolysis of the sample29. Extensive
counting rendered a statistical significance exceeding 3 sigma above
background and noise for this response. The response, nonetheless, was far
short of the pre-mission criteria for life. The PR Experimenter concluded
that the signal was of chemical origin.
Seeking phototrophs, the PR was the most Mars-like
experiment (no water was added). This made it difficult to get a response
from terrestrial soils. Cultured microorganisms were frequently added to
test soils to get a response. The PR operated on the presumption that
martian organisms, under their native environment, would produce a
response.
Overlooked until now is the obvious fact that the low,
but significant, PR response was from pyrolysis of the organic matter that
had been created within the instrument on Mars. The UV filter did
not completely eliminate the formation of organic matter. Pre-mission
tests30,31 of the PR had shown that, even with the optical
filter, organic matter accumulated on sterile test soils. The PR results
on Mars indicate that the formation of organic matter is
proceeding.
2. H2O2: The atmosphere
of Mars produces H2O232,33. It was
theorized34,35 that the H2O2 precipitates
onto the Mars soil. The H2O2 and other oxidants
produced from it were assumed to be in the soil sample and to have
oxidized the LR organic substrates to release radioactive gas. It was
proposed36 that the oxidant(s) also released the oxygen
detected in the Viking GEx experiment. This oxidative chemistry also was
credited with having cleansed the surface of Mars of any organic material,
including microorganisms.
The most telling evidence against the
H2O2 theory is in a just-published
report37 of very sensitive Earthbased IR telescopic
measurements made through the entire column of the martian atmosphere. No
spectrographic feature for H2O2 was found. The
sensitivity of the instrument reduces the upper limit for
H2O2 in the atmosphere of Mars to 30 ppb.
Table
2 presents the amounts of martian H2O2 predicted
by current leading H2O2 theorists. Sensitive to, or
near, these projected amounts, the new experiment seriously weakens the
H2O2 theories.
Other unresolved difficulties have been
reported38 for all theories attributing the LR Mars results to
H2O2 under martian conditions.