Saturday, May 3, 2008

How to Colonize the Solar System, Part II

In the last article, we looked at the moon as a potential colonization spot. This location would make an ideal staging point for further solar system (and eventual possible galactic) colonization due to the low escape velocity (i.e., ships could attain higher velocities more quickly when embarking on interplanetary missions). This time we will look at our nearest neighbor (discounting the moon, of course), Venus. (See also the Wikipedia article on Venus.)

Some will wonder if there's any possibility of colonizing a planet whose surface temperature is over 460 degrees Celsius (860 degrees Fahrenheit); which has a surface air pressure equivalent to being about a kilometer (over 1/2 mile, about 3300 feet) below the earth's ocean; which has an atmospheric density so thick that a human could actually swim through the atmosphere at the surface; whose atmosphere consists primarily of Carbon Dioxide with the remainder being mainly Nitrogen; and which has large amounts of sulfur dioxide clouds which create sulfuric acid rain. While initially daunting, there exist several possibilities for the potential colonization of this seemingly uninhabitable world. Several ideas have been proposed for the terraforming of Venus (see generic terraforming article at Wikipedia). We will eventually look at these concepts and ideas, but there is another possibility that provides a more immediate chance for colonization of this environmentally hostile world. That is a "floating colony."

The atmosphere of Venus varies in its temperature and pressure over its distance from the surface. Of particular interest is the area approximately 50 kilometers (31 miles) above its surface, as at this location the atmospheric pressure is approximately 1 bar (i.e., the same as the earth's surface air pressure). In addition, the temperature at this height varies between 0 and 50 Celsius (32 and 122 Fahrenheit). These conditions are near identical to earth's temperature and atmospheric pressure. Also, a breathable-air mixture (79-21% Nitrogen-Oxygen mixture) would be a lifting gas in the Venusian atmosphere (similar to Helium in the earth's atmosphere), so a large "balloon" of human-breathable gas would simply float at that height in the Venusian atmosphere. Since the atmospheric pressure would be the same both inside and outside the vessel, any damage to the vessel could be repaired before losing a large amount of the interior breathable gas (there would be no great rush either into or out of the vessel). This type of "floating colony" would likely consist of several to many of these vessels, each being a localized "city" within the Venusian floating colony.

These floating colonies would provide the opportunity to perform additional research on Venus, as well as providing the opportunity to research and attempt terraforming of the Venusian environment. However, it also provides the opportunity to experiment on a world where global warming has gone to the extreme, where runaway greenhouse warming is the highest in the solar system. It is believed that Venus used to be earth-like in its atmosphere and temperature, but that prior inhabitants failed to take action against the Venusian-induced global warming until it was too late, and the planet was unable to cope with the effects that its inhabitants wreaked on it. Thus the pleasant Venus turned into what we have today. And it happened in only a couple of years, which should be a warning to us here on earth. However, what was unfortunate for the previous inhabitants of Venus turns out to be a blessing for us on earth, since we now have the opportunity to test various theories and methods for dealing with the potential runaway greenhouse effect here on earth.

There are additional benefits of floating Venusian colonies as well, including marketable enterprises. For instance, the high carbon dioxide content of the atmosphere would make creation of carbonated beverages a very easy task. Instead of having to force the carbon dioxide into the water, as is done on earth, water could simply be lowered into the higher-pressure, lower atmosphere on Venus, uncovered (which would cause the water to absorb the carbon dioxide), covered, and retrieved. This carbonated water could then be made into various carbonated beverages to be used on the floating colonies and exported back to earth. While initially this would seem to be a cost-prohibitive effort (the cost of transportation of water from earth to Venus and carbonated water from Venus to earth would seem to outweigh the cost savings of the carbonization process on earth), this effort could be sidelined onto the regular transport of supplies (and possibly personnel) between Venus and earth and could help offset the base cost of the scientific mission and resupply efforts. In addition, this would help the terraforming efforts by reducing the amount of carbon dioxide in the Venusian atmosphere, since the atmosphere will need to be reduced in amount (due to its high surface pressure) as well as changed in composition.

Once the floating colonies are in place, terraforming efforts could be undertaken. One of the greatest challenges would be the day/night periods. Venus rotates slowly relative to its orbital period, causing "day" on Venus to last for about 117 earth days. While humans are incredibly adaptive creatures, most people would be unable to stay awake for 156 days and then sleep for 78 days (that's an equivalent 16/8 split of the typical 24-hour day on earth applied to a 234-day day on Venus). There are several methods to attacking this daylight problem, for instance:
  • Setting up "sunshades" that orbit the planet, creating artificial 24-hour day/night periods by casting large shadows on the planet; these would unfortunately likely be cost-, material-, and construction-prohibitive.
  • Setting up "sunshades" that float in the atmosphere, again creating artificial 24-hour day/night periods; these would be simpler, smaller, and cheaper, but would likely not create a full "night" period due to inefficiencies and atmospheric reflection of sunlight.
  • Changing the orbital period of the planet; while this might seem like a daunting task, it could be accomplished by causing asteroids to be slung in paths near the planet which would alter the rotational frequency. (This is somewhat like the proposal to use asteroid fly-bys to alter the earth's orbit in about a billion years to avoid having the earth engulfed by the expanding sun.)
  • Ignore it; people near the poles of the earth experience long periods of light and darkness and simply adapt by following regular patterns of awake and asleep times.
Other challenges involve altering the composition and volume of the atmosphere such that humans could survive on the surface. Presumably the temperature would fall in line once the atmosphere was "corrected" to earth-like properties. At this point, we would have a "second earth" which would be available for the next 7 billion humans (the approximate current world population). We would also been able to figure out how to combat the global warming problem on earth (which, as you know, will end all life on earth within the next three years; in other words, we need to get working on this Venusian colony before it's too late).

The next installation of this colonization series will look at one of the most talked about worlds in our solar system, Mars, which has long been supposed to be already occupied by little green men. In addition to the potential of colonization, we will discuss the possibility that the planet is already populated and the impact this would have to our human colonization efforts. Stay tuned!

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