Breathing with the Earth
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the spark experiments—yield a roughly equal mixture of D and L mole-
cules. However, all living things consist of either D or L forms, depend-
ing on the species, but never both.
We must conceive of the first living things as something unexpected,
not just simpler versions of what we see around us. They couldn't have
been cells; they couldn't have had a DNA-RNA-protein system, a living
membrane, or a nerve impulse network.
We can try to define the bare minimum, the processes that must be
available before an entity can be called living. There must be a way to
receive information about external conditions, process it, and store it so
that the data change the being's response to the same stimulus in the
future. In other words, a sort of crude consciousness and memory must
be present from the first. A life-form must also be able to sense damage
and repair itself. Third, we can expect that it would show some sort of
cyclic activity, perhaps tuned primarily to the circadian rhythm of the
lunar day. Self-replication, one of the main requirements in the DNA-
based theory, can be dispensed with. An organism that can fully heal its
injuries is theoretically immortal. The criteria for life can be summarized
as organization, information processing, regeneration, and rhythm.
The funny thing is that all of these criteria are met by the activities of
semiconducting crystals. Semiconductivity occurs naturally in several in-
organic crystals, including silicon, one of the most common elements,
and the rare earth germanium. Moreover, extremely small amounts of
contaminants will change the crystal's electrical properties dramatically
in doping. The earth's volcanic mixing would have produced minerals
with a wide variety of current-handling abilities to start from. Most
important, the piezoelectric, pyroelectric, photoelectric, and other re-
sponses of semiconducting crystals could have served as an analog
method of processing and storing information about pressure, heat, and
light. Moreover, repeated passage of current through some semiconduc-
tors permanently changes the materials' characteristics so as to make the
same electrical responses easier in the future. Movement of electrons
along the crystal lattices inevitably would have been shaped by geo-
celestial cycles in the earth's electromagnetic field, as well as by the
fields around other such crystalline organisms nearby—providing a sense
of time and information about the neighbors. The currents also would
have instantly refllected any loss of material and guided the deposition of
replacement atoms to restore the original structure.
The idea of certain rocks, in the course of a billion years or so, gradu-
ally becoming responsive to their surroundings, growing, learning to
"hurt" when a lava flow or sulfuric rain ate away part of a vertex, slowly