As space exploration brings us closer to the distant planets of our solar system and beyond, the case for habitation or colonization new worlds becomes clearer and clearer. Having long been a dream of many, extending humanity to a new planet might soon be possible. Born in the realm of science fiction, terraforming, literally meaning "Earth-shaping," is a hypothetical process of modifying a candidate planet's atmosphere, temperature, and ecology to be similar to that of the Earth. The fields of both science and science fiction have been entertained by the idea terraforming since the early 1900s. Interestingly, methods and hypotheses oven converge to the point where it's unclear which discipline inspired which. However, threats to our home planet are becoming more imminent, and terraforming might actually be a plausible solution.
The first picture of Earth was beamed back from the moon in 1968. Named Earthrise, the photograph below provides a perspective of our home planet that we never saw before. And for the first time, we recognized the fragility and isolation of Earth. "The most influential environmental photograph ever taken" ignited the environmental movement of the 1970s. Our efforts to protect our home from carbon dioxide, ozone depletion, greenhouse gasses, CFCs, etc., proved not to be enough. The year 2012 has already been named the hottest year in recorded history. Without serious intervention, global warming will continue to threaten human habitation on Earth.
Humans aren't the only dangers to Earth. In fact, in July 1994 we watched from the Galileo orbiter a comet named Shoemaker-Levy 9 impact the planet Jupiter. This was the first direct observation of collision in our solar system. The most poignant fact we learned was that the impact was roughly 3,700 miles across - or one Earth radius. (Compare the sizes below) Jupiter shrugged off the collision, whereas Earth wouldn't fare quite as well. In a cosmic sense, we are sitting ducks, and it's only a matter of time.
Carl Sagan was the first to write on the possibility of transforming Venus into an Earth-like habitable planet in a 1961 issue of the journal "Science." Sagan hypothesized that "seeding the atmosphere of Venus with algae would convert water, nitrogen, and carbon dioxide into organic compounds," and the building blocks of life. The process would remove carbon dioxide from the atmosphere and reduce the greenhouse effect, which would in turn bring the temperature of Venus down to a "comfortably habitable" temperature. However, as technology progressed, we discovered Venus's atmosphere contains highly concentrated sulfuric acid, which would kill any known forms of algae. In fact, in 1979, Michael Hart's paper on "Atmospheric Evolution, the Drake Equation and DNA: Spare Life in an Infinite Universe" describes the "Goldilocks phenomenon", or the habitable zone. Hart describes how the planet Mars would be better suited for terraforming. Earth lies in the middle of Venus and Mars. Venus's closer proximity to the sun and dense, carbon dioxide laden atmosphere accelerates the Greenhouse Effect to where the surface temperature averages 863.6°F. On the other hand, Mars is the fourth planet from the sun, greatly diminishing its effect. Compared to Earth, Mars has an extremely thin atmosphere and is cooler. Scientists believe that warming up and thickening Mars's atmosphere would be much easier than cooling down (we already have difficulty with that here on Earth) and thinning Venus's atmosphere.
Interestingly, scientists weren't the first to determine Mars was the most suitable candidate for terraforming in our solar system. Since the 1950s, science fiction writers have explored ways of making a habitable Mars. Arthur C. Clarke, author of The Sands of Mars, was the first in 1951. The story is set on Mars, where humans have settled to further research the planet. "Project Dawn" is an initiative to ignite the largest and closest of Mars's two moons, Phobos. The resulting heat would last 1,000 years and would act as a second sun, increasing the temperature, and thereby terraforming the planet to become more earth-like. It's particularly intriguing how Clarke understood that to make Mars habitable, the planet needed to be warmer. This is the first step of a modern terraforming plan, and the fact that Clark described this in the 1950s blurs the distinction between science and science fiction.
|Further blurring the lines between science and science fiction, Charles Darwin unknowingly performed the first terraforming experiment almost two centuries ago. Darwin, known for the theory of evolution, and Joseph Hooker transformed a barren, volcanic island in the middle of the Atlantic Ocean into a lush, diverse ecosystem. On his voyage around the world with the Royal Navy, Darwin stopped at Ascension Island. The Navy was interested in establishing a base in a strategic location between South America, Africa, and St. Helena (to keep an eye on the exiled Napoleon). However, the island was the remnants of an ancient volcanic eruption - and completely devoid of life and fresh water. Darwin convinced the Royal Navy to carry out an elaborate plan. In 1850, they began by shipping trees and soil to Ascension. Darwin hypothesized that trees would capture the rain, reduce evaporation and create more fertile soil. By the 1870s, other trees like eucalyptus, bamboo, and banana covered the island. Dr. Dave Wilkinson, an ecologist at Liverpool John Moores University, first visited Ascension in 2003. He was baffled by the out-of-place species on the Island. Upon learning of Darwin's involvement in creating an artificial island, Wilkinson explained, "they created a self-sustaining and self-reproducing ecosystem in order to make Ascension Island more habitable." Wilkinson believes similar principles can be applied to terraforming Mars. He explains, "rather than trying to improve an environment by force, the best approach might be to work with life to help it find its own way." Today, scientists unfortunately overlook the story of Ascension Island and Darwin's terraforming experiment.|
Darwin's successful application of terraforming might have inspired H. G. Wells to write the science fiction novel The War of the Worlds. Written 1895-97, it is one of the first examples of conflict between humans and extraterrestrial intelligence. In the novel, Martians land on Earth in order to exterminate the population and claim the planet for themselves. They bring with them the "red weed" which grows and reproduces explosively, overpowering plant life on Earth. Today, we might call this xeno-terraforming, or literally, "foreign Earth shaping," because the Martians make the Earth more suitable for Martian life.
The concept of terraforming is over 100 years old, though the term wasn't coined until the 1950s. From The War of the Worlds, there have been countless of novels, comic books, films, television shows, and even video games based on the premise of terraforming alien planets. It's a go-to science fiction technique to establish the human race beyond the confines of Earth. In reality, overpopulation, nuclear proliferation, disease, global warming, etc., are all very real, manmade threats which may force us to leave our home. However, we shouldn't driven by our survival instincts. The manmade problems should be solved on Earth. If we are to leave our planet, it should be our inner pioneer should drive us; the mentality that built civilizations, crossed oceans, and walked on the moon. Walking on another planet is the next logical step in our advancement as a species, it proves to our explorer ancestors that we haven't settled, becoming self-absorbed and only looking within ourselves.