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/" 12/19/83 Dec 20  1983 SAM/275
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Preface to NASA workshop on
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NASA SP-476 1985   Wood, J A and Chang, Sherwood  eds.
  The cosmic history of the Biogenic Elements and Compounds

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			Joshua Lederberg
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			The Rockefeller University
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	In inviting me to submit these prefatory remarks, the
editors were most generous to recall the speculations (1) that
had inspired my own interest in the biological exploration of
space twenty-five years ago.  These started from nothing more
tangible than staring at the tables of cosmic abundance of the
nuclides, and pondering how condensed matter could have evolved
without the production of macromolecules.
	Most astronomers then did not unify their images of
condensation with the valence theory of chemistry.  The
overabundance of hydrogen is indeed an embarrassment to remind
us that the prevalence of any organic molecules less reduced
than methane is out of equilibrium:  that fact given, we should
be little more surprised to find complex organic molecules in
interstellar space than on Jupiter or in the comets.  From that
perspective, Earth's advantage is in having most of its hydrogen
blown away, though not to the extremes that Mars seems to show.
That is, an earth more reduced than our planet would have
difficulty in sustaining organic molecules beyond methane:  a
model inverted from some other conventional representations.  If
we accept the stability of such molecules on a reduced earth,
why not also in space?  Why look later than the primary
condensation for the abundance of carbonaceous species that we
must postulate as a precondition for the emergence of life?
Indeed, any process that permits the large scale production of
oligomeric carbon could hardly avoid its polymerization, opening
further questions as to the selective factors that would
condition the chemical forms of large scale condensed matter.
Planetary bodies would furnish idiosyncratic local environments;
but most of that matter would be found in the relatively
homogeneous interstellar space.  We could then ask for a
unifying cosmic description of the primary modality of chemical
evolution.  To the biologist, this perspective does not yet
advance our understanding of the origin of life -- the really
difficult enigma remaining still the progression from random to
well-ordered and self-replicating polymers.  A cosmic seat of
early biological evolution does alter the locus of
improbabilities, from the anthropic  curiosity that life could
start on one planet, to an improbable universe which
nevertheless generated life with high probability.  With what a
priori probability we cannot say: does the cosmic condensation
already furnish enormous quantities of matter preadapted to the
requirements of biological macromolecules?  Will we find the raw
material of DNA already present there?
	These were naive and elementary questions, hardly to be
justified even as assertions.  Nevertheless, they have been
greatly bolstered by the experimental and observational work of
the last two decades, as evidenced by the report of this study
group.
	Perhaps the most foolish bit of wishful thinking
expressed in 1958 was the expectation that the surface of the
Moon, presumably unweathered, would show some accumulation of
primitive condensate.  At that time, regolith models with
extensive reworking of planetary surfaces by tectonic and
meteoritic activity were less widely understood.  For the same
reason today we should perhaps be cautious in our expectations
of cometary composition; nevertheless this doubtless provides
the closest approximation to accessible samples of 'interstellar
matter' we are likely to achieve for some time.
	As to Mars, the possibility of life (and certainly of
fossil life) should not be written off as quickly as some
authors might admit.  We have as yet sampled only two (very
similar) habitats; there remain many enigmas of fossil drainage
patterns, as well as the unexplored polar cap zones.
	Altogether, we are at a stage where each new finding
raises many more new questions than it puts to rest; and many of
the most trenchant questions are well stated in the study.  The
greatest value of the intellectual synthesis given in this
volume is its provocation of new experiments and measurements
focussed on very large and important aims -- important for
theoretical understanding of our own origins, and with grave
practical import ranging from earthquakes to energy sources on
our own planet.

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	(1)   Lederberg J. and  Cowie D.B.,  Moondust
		Science 127: 1473-1475. (1958)