A Second Earth?
A Second Earth? - A Human’s Dream
The dream of humanity colonising another planet and building a new home has been portrayed through various mediums. In 2014, director Christopher Nolan's film "Interstellar" depicted humankind's journey beyond Earth in search of a new home in outer space. Additionally, humans have created games like "Surviving Mars" to simulate colonisation on other planets, providing people with a taste of life beyond Earth. However, this dream is not confined to the realms of video games and movies; in reality, people have been actively working toward this vision for a considerable period of time.
The history of mankind's space exploration dates back to the 20th century. In 1957, the Soviet Union launched the first artificial satellite into space, marking the inception of the space age. Humankind’s journey for space exploration arrived at a significant milestone in 1969 when NASA's Apollo 11 mission confirmed the success of humans landing on extraterrestrial terrain. In recent years, proposals for colonising other planets, particularly Mars, have gained momentum. For instance, SpaceX, a company founded.
founded by Elon Musk, has emerged as a key player in advocating for Mars colonisation. SpaceX has shown continuous dedication in the development and manufacturing of Starship, a commercial spacecraft designed to transport people to Mars.
Disturbingly, in 2018, humans were depleting natural resources 1.7 times faster than the Earth could renew them. This unsustainable trend poses a significant threat, potentially rendering Earth uninhabitable in the near future. The historical extinction of dinosaurs serves as a stark reminder that catastrophic natural disasters leading to the eradication of entire species can occur unexpectedly. Given the unpredictability of such events, the need to find a new habitat becomes paramount to guarantee the continuous survival of humanity.
Mars has become the preferred candidate for human colonisation due to its similarities to Earth. Scientists have discovered evidence indicating the presence of water on Mars, a crucial element for human survival. Despite the cold temperatures ranging from -153°C to 20°C, Mars remains the most suitable planet for colonisation when compared to other celestial bodies. Although definitive signs of life on Mars have not yet been identified, it holds the distinction of being the closest and most viable option for colonisation.
Two astronauts on the surface of Mars
So… should all mankind start working on building our new home on Mars now?
A Second Earth, on Earth – Biosphere 2
In fact, there was once a similar project in Oracle, Arizona, to assess whether humans were capable of living in a self-sustaining closed ecosystem in outer space. In the 1980s, American engineer John P. Allen conceived the terrarium design for Biosphere 2. Construction began in 1986 and was completed in 1989. The name for this terrarium, “Biosphere 2”, derived from the idea that it is modelled on Earth, “Biosphere 1”. The size of Biosphere 2 is 3.14 acres (approximately 13,000 m2), which contains five major biomes: ocean, mangrove wetlands, tropical rainforest, savanna grassland, and fog desert. Additionally, there were agricultural and human habitat areas in Biosphere 2.
Biosphere 2
rainforest, savanna grassland, and fog desert. Additionally, there were agricultural and human habitat areas in Biosphere 2.
On September 26, 1991, four men and four women, popularly referred to as “Biospherians,” were sent and sealed inside the terrarium for the first mission. Despite being designed to ensure the continual survival of the Biospherians without relying on supplies from external environments, their lives were still placed in jeopardy. The first challenge they faced was a decline in oxygen content. The oxygen inside the facility dropped steadily from 21% (by volume) to 14% in 16 months.
The Biospherians in Biosphere 2
This oxygen content is equivalent to the oxygen at an elevation of 4,360 m! Some Biospherians faced difficulties in performing daily tasks and started experiencing symptoms like sleep apnea and fatigue. For the safety of the Biospherians, oxygen was pumped into Biosphere 2. Scientists investigated the cause and found that microbes added to the soils to promote plant growth were using oxygen to metabolise the excess organic matter.
Nevertheless, food production in Biosphere 2 was low, as the rate of respiration of plants was greater than the rate of photosynthesis. It was predicted that the cause was that El Niño produced more clouds, reducing the sunlight that penetrated Biosphere 2. Another cause was the low oxygen content in the facility.
Due to the high respiratory rate, it was predicted that the CO2 level would reach 4% (which is 100 times more than the CO2 presence in the atmosphere!). Yet, scientists discovered that the CO2 level in Biosphere 2 was only 0.4%. After investigating the leak and the reaction of CO2 with compounds in soils and water, it was found that the concrete in Biosphere 2 was consuming a large amount of CO2. Calcium hydroxide from the concrete would react with CO2 to form calcium carbonate. Under normal conditions, the reaction would take place at a slow pace. However, due to the excessive amount of CO2, the reaction was accelerated. In just over two years of the first mission, calcium carbonate had accumulated to a depth of more than 2 cm in Biosphere 2’s concrete.
The Biosphere 2 mission turned out to be a failure, as it could not support human survival in a closed ecosystem. In June 2011, the University of Arizona took over the ownership of Biosphere 2. It is now used as a laboratory for large-scale projects such as the Landscape Evolution Observatory (LEO) and is open for the public to visit.
Shatter of Dreams?
The dream of human colonisation in outer space is attainable; however, with current technological advancements, there remain numerous challenges for us to overcome. Extensive research and studies must be undertaken to comprehend the necessary measures for constructing a safe habitat for humans beyond our planet. From a financial standpoint, the construction of Biosphere 2 alone demanded an investment surpassing 200 million USD. Given this substantial cost, one cannot help but ponder: what additional financial resources will humanity need to allocate for the establishment of a new home in outer space?
Therefore, it is crucial to prioritise the habitability of our current home, Earth. Every individual plays a vital role in ensuring that we have sufficient resources essential for our survival, such as energy and food. It is incumbent upon each of us to contribute to the protection of our planet and the conservation of resources, thereby promoting sustainability.
After all, why build a second home when you are already home?
