Significant Achievements in Space Bioscience 1958-1964United States. National Aeronautics and Space Administration
Science
Significant Achievements in Space Bioscience 1958-1964
United States. National Aeronautics and Space Administration
Biology; Space flight
A comparison between the photographs of the organized elements observed
in the Orgueil and Ivuna meteorites and the synthetic proteinoid
microspheres observed by Fox ([ref.25]) point to similarities between
the two. One inference from this finding is that the organized elements
in carbonaceous chondrites were never alive but, rather, should be
considered as natural experiments in molecular evolution. Also, these
similarities strengthen the belief that the laboratory experiments are
similar to the natural experiments in space.
In cooperation with the Smithsonian Astrophysical Observatory, NASA has
a network to track meteors in the Midwest (South Dakota, Nebraska,
Kansas, Oklahoma, Iowa, Missouri, and Illinois). Photographs of meteor
trails are used for scientific study, and attempts are made to track and
recover meteorites for examination for traces of organic material of
extraterrestrial origin.
Fundamental research in terrestrial organic geochemistry has shown that
ancient sediments and drill core samples subjected to organic analysis
contain certain stable biochemical components of past life. This
preserved record is significant not only in studies of early-life
chemical pathways but also in studies of the interaction of organic
matter with the geological factors. Since life on any planetary body
will interact with the soil, or surface material, it is of interest to
understand the relationship.
CONCEPTS FOR DETECTION OF EXTRATERRESTRIAL LIFE
It is not possible to present completely convincing evidence for the
existence of extraterrestrial life. The problem often reduces to
probabilities and to estimates of observational reliability. In almost
all cases the evidence is optimistically considered strongly suggestive
of—or, at the worst, not inconsistent with—the existence of
extraterrestrial life. Alternatively, there is a pessimistic view that
the evidence advanced for extraterrestrial life is unconvincing,
irrelevant, or has another, nonbiological explanation.
In studies of the laboratory synthesis of life-related compounds and its
significance concerning the origin of life, several results seem to
suggest that organochemical synthesis is a general process, occurring
perhaps on all planets which retain a reducing atmosphere. The
temperature ranges must be such that precursors and reaction products
are not thermally dissociated. The reaction rates for the synthesis of
more complex organic molecules diminish to a negligible value when the
temperature range is below 100° C.
Besides the planetary parameter of temperature, an even more fundamental
necessity for a living state exists—a liquid solvent system. For
terrestrial life forms, water serves this purpose. Water has this and
other properties of biological significance because of hydrogen bonding
between adjacent molecules in the liquid state.
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