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incredibly hot and inhospitable that
no one seriously believes physical life
could exist there.
Most recently, the Voyager mis–
sions to J upiter, Saturn and beyond
have revealed sorne startling and
amazing views of these distant plan–
ets and their satellites. J upiter, the
center of a miniature solar system of
its own, was once thought to possibly
harbor life, and its moons were also
considered life-carrying candidates.
Now, with the detailed photos
returned by the Voyager probes, the
prospects for life seem near zero in
the Jovian system. J upiter is a seeth–
ing hall of gas, possibly covering an
icy core of frozen hydrogen. Its satel–
lites are also desolate, forbidding
worlds. The same can be said for
Saturn, its rings and moons. And the
remote planets beyond Saturn offer
virtually no hope for life either.
Abundant Llfe In Galaxy?
But man's exploration of the solar
system constitutes such an infinitesi–
mal part of the entire Milky Way
galaxy that even such negative find–
ings have not significantly altered the
opinion of many who would like to
believe that other stars may have
planets with intelligent life.
After all, space enthusiasts point
out that there are sorne two hundred
billion stars in our Milky Way gal–
axy, and sorne of these stars "surely"
have planets with environments suit–
able for life. A Rand Corporation
study concluded there should be 600
million planets
suit~ble
for life in just
our galaxy.
Such arguments have seemed co–
gent to laymen and "experts" alike.
But now there are a number of
scientists that are reconsidering the
credibility of the belief that physical
life abounds in the universe. Such
reevaluations are based on severa!
factors . First, it is true that the more
man explores the solar system, the
less likely it appears that life exists
anywhere beyond the earth. lndeed,
most scientists a re now ready to
admit that the probability of life in
the solar system (outside the earth) is
near zero.
But more importantly, astrono–
mers have been trying for nearly two
decades to detect telltale radio sig–
nals from space that would betray
the existence of another civilization.
24
Yet their mighty radio antennas have
failed to record any signa! that has
the mark of an extraterrestrial civili–
zation.
Other Factors
Other factors bave also caused a
rethinking of man's place in the uní–
verse. Dr. Micbael H. Hart of Trinity
University in San Antonio, Texas, has
recently challenged the belief that
extraterrestrial intelligence must be
common in the cosmos.
According to Hart, it is quite
possible that our earthly civilization
is the only one of its kind. Hart
reasons that, far from being com–
mon, civilized life must be exceeding–
ly rare, and the life we have on earth
may even be unique.
Using computer analyses, Hart has
found that the conditions necessary for
life are far more restrictive than has
been commonly thought. "The conclu–
sion ofthe study," says Hart, "was that
existing estimates of the number of
planets that could produce advanced
civilizations would have to be reduced
by a factor ofbetween 100and 1000. In
fact, 1 think ours is the only advanced
civilization in the universe and almost
certainly the only one in our galaxy."
Hart's computer studies showed
that our earth just barely makes it as
a suitable abode for living things. At
a distance of 93 million miles from
the sun, earthly temperatures have
supported life. But if our earth had
been placed into an orbit only five
percent closer to the sun, a runaway
greenhouse effect would have turned
the planet into something like Ve–
nus- with its surface temperatures
close to 900 degrees Fahrenheit.
By contrast, if we were only one
percent farther from the sun, then
runaway glaciation would have en–
veloped the earth and the planet
would have become a barren desert
similar to Mars.
In addition, while a few meteorites
from outer space have contained
amino acids in exceedingly small
amounts, the jump from such simple
organic (carbon-based) molecules to
life is incredibly remote. "Science
has still failed to fathom this process,
and we cannot assume life would
easily or automatically evolve frorrt
simple nucleotides," contends Hart.
The narrowness of the "habitable
window," concludes Hart, greatly
limits the number of planets that
could sustain (or "evolve") advanced
civilizations.
Man Unique in the Universe?
Hart is not alone in such reconsidera–
tions of the evidence. Dr. Carl Sagan,
Cornell University astronomer who
has popularized the notion of life on
other worlds, now believes that more
recent astrophysical discoveries have
significantly reduced the probabili–
ties of tbe occurrence of intelligent
life elsewhere in the universe. Sagan
coauthored the book
l ntel/igent Lije
in the Universe
with Soviet astrono–
mer Iosif S. Shklovsky.
But even Shklovsky appears to
have become more conservative in his
estímate of the chances for detecting
extraterrestrial intelligence, contend–
ing that intelligent life in the cosmos
must be very rare. " I t looks as
though our sun, that strange and
solitary star surrounded by a family
of planets, is most likely a rare
exception in the stellar world,"
Shklovsky recently wrote in a Soviet
science journal.
Dr. Paul Davies, mathematician at
Kings College, London, thinks that
the universe
could
be considered to
be a lucky accident. Davies contends
that a chance occurrence seems out
of the question, and he believes sorne
other explanation must be found.
"The universe we live in seems to be
a very unlikely place," says Davies.
"Random processes and statistical
fluctuations on cosmological time
scales could easily have made the
universe quite inhospitable to life.
Are we just lucky? Or is there sorne
deep significance to the fact that we
live in a universe just right for us?"
Davies contends that the expan–
sion of the universe is remarkably
uniform in all directions, implying
cooperation between widely sepa–
rated regions of the cosmos to expand
to the same rate everywhere. Such
"cooperation" and higlily organized
behavior seems so improbable that
the universe seems almost planned.
"So from the gravitational point of
view," adds Davies, "it seems tbat
the world is a very special place
indeed."
" Big Bang" Finely Orchestrated
Science, of course, currently con–
tends that the universe began with a
The
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