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September 1961 Popular Science
 [Table
of Contents]
Wax nostalgic about and learn from the history of early
electronics. See articles from
Popular
Science, published 1872-2021. All copyrights hereby acknowledged.
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 Raise your hand if you watched the original
1980 Nova "Cosmos:
A Personal Journey" TV series, hosted by überastronomer Carl Sagan. My
hand is up. In fact, that might be what piqued my life-long interest in
astronomy. I was in the
U.S. Air Force at the time, stationed at Robins AFB, Georgia, as an
Air Traffic Control Radar
Repairman. The show motivated me to buy my first "real" telescope, a
Criterion RV-6 Dynascope, a Newtonian model on an equatorial mount. I was surprised
to run across this 1961 Popular Science magazine article entitled, "How
to Colonize Venus." This might have been Sagan's initial foray into the public domain.
Hard as it is to believe, at the time astronomers did not know that
Venus' atmosphere,
composed largely of carbon dioxide (CO2), supports clouds of sulphuric
acid (battery acid) raining down, and the planet's surface has a temperature of
more than 800° F and a pressure of more than 1300 psi. Sagan posited
that the plant's surface was likely arid, dusty plains driven by strong winds, and
than any manned mission must be prepared for such hostilities. In the 1960s and
1970s, both the U.S. and U.S.S.R. sent unmanned probes to Venus, whereupon the true
nature of the planet's atmosphere was discovered. Only the Russian
Venera series
actually landed on the surface. The couple craft which managed to reach the surface
lasted only minutes. It's a good bet there won't be any manned missions to the surface
of Venus anytime soon.
How to Colonize Venus
 By Carl Sagan
The planet closest to Earth is Venus (it swings in to 25,000,000 miles). It is
also one of the most mysterious. That's because you can't see the planet, only the
pale, lemon-yellow clouds that cover it all the time. The mystery may be cleared
up fairly soon: The Russians have sent a fly-by rocket probing past Venus (not very
close, though), and we're planning to launch a Venus probe of our own next year.
Meanwhile, Carl Sagan, researcher at the University of California, has compared
bits and pieces of astronomical evidence to deduce the nature of our old Evening
Star (most inhospitable, he says), and to propose a weird scheme for making it comfortable
for human space settlers ("microbiological planetary engineering," he calls it).
Since no one can see the surface of Venus, scientists have felt free to let their
imaginations run, and they sure did. There are four theories, all seriously proposed
by recognized experts, and all wildly different:
1. It's dripping wet, covered with swamps. (The clouds were assumed to be water
vapor, like our clouds.)
2. It's sunk in a global ocean of Seltzer water. (Much carbon dioxide was detected;
this would carbonate the ocean.)
3. It's covered by a huge pool of oil. (If there were originally a lot of hydrogen-carbon
compounds, they would react with water to make all that carbon dioxide - and leave
the planet coated with leftover hydrocarbons.)
4. It's an arid, windswept desert blanketed by dust clouds. (Until recently,
not a trace of water could be detected.)
Venus Photographed in Blue Light at Mt. Wilson
Commented Sagan in his report in the journal Science, "Those planning manned
expeditions to Venus must be exceedingly perplexed over whether to send along a
paleobotanist, a mineralogist, a petroleum geologist, or a deep-sea diver."
New evidence, Sagan thinks, blasts all these theories except No.4, and this is
not entirely right. The principal" clue is temperature. Venus is apparently heated
by a powerful greenhouse effect - incoming sun heat is trapped by the heavy carbon
dioxide atmosphere and the cloud layer. The surface runs around 600 degrees F.,
more than enough to dry out a swamp, evaporate a Seltzer ocean, or destroy an oil
slick.
There can't be any liquid water. The clouds are ice crystals, but they are 30
miles up, where it's cold. It never rains. The surface is a dead, dry wasteland,
eroded by the wind. The winds should be mild breezes, since the sun's heat goes
mainly into warming up the heavy atmosphere, instead of moving the atmosphere around
the way it does on earth.
No living thing we know about could exist under such conditions. Some life might
carryon in the cool upper atmosphere, just under the clouds. There's not much chance
that it does now, because it is unlikely that life ever got started on Venus - life
brews slowly in a warm thin soup, and that Venus never seems to have had.
This dismal geography does not discourage Sagan. To make Venus resemble home
sweet home, all you have to do is lower the temperature and set some oxygen free
in the atmosphere. That's all. Sagan thinks blue-green algae will turn the trick.
(It looks as if well-trained algae are as essential to space explorers as the compass
was to Columbus.) Here's how:
The algae-microscopic plants that will float in the air- are squirted into Venus'
clouds. There, using carbon dioxide from the atmosphere, water from the clouds'
ice crystals, and sunlight, they manufacture carbohydrate and release free oxygen.
This uses up some water, which is scarce on Venus. You have to get it back. Very
conveniently, the carbohydrate-fattened algae float down to lower, hotter regions
of the atmosphere. The heat there roasts the carbohydrate, releasing carbon and
water.
These two reactions build up the oxygen supply at the expense of carbon dioxide.
As the carbon dioxide goes, the greenhouse effect becomes less efficient and the
temperature drops. As the temperature drops, carbohydrate roasts more slowly, releasing
less water. The loss of water vapor cuts the greenhouse effect and the temperature
still more.
When the surface cools - below the boiling point of water, you have it made.
Pools of liquid water form. Then it rains. The rain brings on the "Urey equilibrium"
- back-and-forth reactions between carbon dioxide and common types of rocks that
stabilize the amount of carbon dioxide gas in the atmosphere. (These reactions won't
go without rain, which triggers the chemical processes and stirs things up.) After
a while, the Urey equilibrium will establish a carbon dioxide level much like that
on Earth, the greenhouse effect will slack off more, and Venus will begin to feel
like Florida.
Posted June 22, 2024
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