Redefining Reality - The Intellectual Implications of Modern Science

What environment on Earth could produce temperatures in the
range needed for life and free hydrocarbons that could be used
to develop simple pre-photosynthetic life forms? The answer, of
course, is the deep ocean system of geothermal vents. Given the
genetic similarities of the deep, shallow, and land-based life forms,
we know they are of a single origin. Because photosynthesis is
more complex than chemosynthesis, there is some reason to think it
developed later as an adaptation.
Further, the Sun’s energy can be stored by living things, but
it is ionizing energy and can damage life, as well. As we saw in
an earlier lecture, the Sun’s rays are used by our skin to produce
vitamin D, but these same rays also destroy vitamin B 9
, folate. Life
forms would have to develop a defense against the Sun. It would be
easier for life to start elsewhere, away from the Sun.
The deep oceans would also provide a more stable environment.
The young Earth was hot, and it took a while before its properties
would be suitable to sustain life, much less give rise to it. The
of energy. This stability would make the deep ocean a more likely
spot for simpler life forms to begin. For all of these reasons, Gold
argues that there is good reason to believe that life on Earth began
in the deep, hot biosphere.
Gold’s hot, deep biosphere theory allows for the possibility of life
forming in places we had thought were inhospitable to life. Life
could begin without a surface temperature like that of Earth, which
means that life similar to what we see on Earth could exist in places
other than Earth. A competing hypothesis, called panspermia, is
that basic life is spread throughout the universe and arrived here
from cosmic dust carried by comets or asteroids, leading us to ask:
Is life purely an earthly phenomenon?
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