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NewsHour
Backgrounders
June 10, 1997:
A Gergen dialogue
with William Broad about his book "The Universe Below."
April 10, 1997:
NASA scientists explain the
findings from Europa.
Browse the NewsHour's science
coverage.
Outside
Links
Browse stories from the New York Times by William J. Broad and others on Europa. (note:
free, but registration is required.)
Browse Simon & Schusters' page on "The Universe Below: Discovering the Secrets of the Deep Sea."
|
 Blair
Gustafson of Sheridan, WY, asks:
I'm not sure I fully understand how these creatures can exist deep
in the oceans under such tremendous pressures. They consist mostly
of noncompressible water, but, then, so do humans, yet we cannot withstand
the deep sea pressures. It seems as though any non-water parts of these
delicate creatures would be destroyed instantly. You mention in the
dialogue with Mr. Gergen that the pressure on an organism at these depths
would be similar to that of an Empire State Building bearing
down; mostly water or not,it seems as though a tube worm would
be destroyed if the Empire State Building was resting on it. Can
you help educate me?
William Broad responds:
And myself. After all, I'm still learning. Two
things. Humans, though mainly made out of water, do possess big cavities
that easily collapse -- the
lungs. As the pressure goes up, lungs quickly
get crushed. (Don't ask me how toothed whales can swim so deep without
lung collapse. I don't know, and I don't think scientists do either.) As
for the non-water parts of sea creatures, they are saved from collapse
by the same phenomenon that we
encounter here at the Earth's surface -- uniformity
of pressure. The earth's atmosphere creates a pressure that surrounds us,
keeping us from feeling flattened  by
it. So too in the deep sea. The Empire-State-building metaphor is perhaps
a poor choice since it implies that the pressure is all downward. It's
not. The styrofoam cups I took down to the bottom of the Pacific a mile-and-a-half
down were uniformly compressed to the size of a thimble, not crushed
flat.
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