- Humanity dreams of becoming an interplanetary species, but currently no other planet in our solar system can support a complex life.
- To make a planet like Mars hospitable to us, we must embark on a massive, decades-long terraforming effort.
- Much of what makes the earth habitable, such as breathing air, tolerable temperatures, etc., is the result of microbial activity from Earth's early history. Can we use the microbial life to make the same changes on Mars?
Three billion years ago, Earth would not have been very comfortable for humans. It was covered with active volcanoes and spewed out carbon dioxide and water vapor. Single-celled life that was scraped off on a diet with sulfur. Most of the atmosphere was carbon dioxide, methane, and other greenhouse gases, which made the air toxic to us and most other modern life on Earth.
Then something happened 2.5 years ago. With what's a snapping of the fingers in geological timescales, the atmosphere in what we call the Great Oxygenation Event was filled with oxygen. The abundance of oxygen meant that new, more diverse types of life could conquer the young planet, such as eukaryotes. A few billion years forward and a complicated, multicellular life as we go around the planet.
Where does all this oxygen come from? Today, we believe that almost all the Earth's oxygen came from Cyanobacteria a tiny, blue-green, single-celled life that had the innovative idea of using sunlight to convert water and carbon dioxide into sugar – that is Photosynthesis. Unfortunately for cyanobacteria, photosynthesis accounts for the unsightly byproduct of oxygen that they throw into their environment.
Every breath we take owes us to cyanobacteria, and this influx of oxygen into our environment is ultimately responsible for why modern earth is so accommodating to life. But what the earth gives also takes the earth with it. Whether due to climate change, a nuclear war, a global pandemic or an unknown disaster – we finally want a new home. But our closest and best hope for a new home – Mars – has no oxygen.
It really does not have much atmosphere.
Scientists hope to restore the Great Oxygenation Event on Mars in the same way as on Earth. through the use of microbial life to build the environment for us.
Terraforming Mars with microbes
The illustration of a Mars through a terraforming effort.
While Mars may be different from the early Earth In many ways, it has some key features that could make a microbial terraforming project work. Mars has an atmosphere that consists of 95 percent carbon dioxide. This is half of the ingredients that cyanobacteria need to produce oxygen. The other ingredient, water, is scarce on the Red Planet, but there is evidence that it exists. We know that ice is so abundant in the poles that, if we melted it, Mars would be covered in an ocean 18 feet deep.
On Mars there is already some liquid water to be sure – only in very small quantities. On Mars, we have seen features called recurring gradients. These are dark lines that move along the slopes during the Martian summer and fade away in the winter. It is believed that these dark lines are streams of water that come and go with the seasons.
This image of the side of a Martian crater shows recurring gradients. The dark lines that descend from the crater's slope come and go with the seasons that might point to running water.
To form Terra Mars we would start with areas where liquid water is present there draining many cyanobacteria. Granted, it would be a bit more complicated than hearing that, but that's the essence of the idea. We also want to include microbes that produce greenhouse gases.
Mars has the opposite problem as the earth; We want to make Mars hotter and thicken its atmosphere so the polar ice can melt. More water means more opportunities for microbial life to do its job. Not to mention that the current climate on Mars is too cold even for the toughest people – it's on average minus 81 degrees Fahrenheit, though temperatures can vary widely.
The idea of using microbes to launch a terraforming project on Mars is so promising that NASA has already begun preliminary trials. The Mars Ecopoiesis Test Bed is a proposal for a device to be included in future robot missions to Mars. It would look like a drill with a Hallow chamber in it. The drill would bury itself in the Martian soil, preferably somewhere with liquid water. A container full of cyanobacteria would enter the chamber and sensors would detect if the microbial life produced oxygen or other by-products.
The first phase of this project was conducted in a simulated Mars environment on Earth and the results were positive. Nevertheless, there are some big challenges that we have to face if we want to use microbially terraformed Mars on a large scale.
The Mars Ecopoiesis Test Bed. 19659005] Mars lacks something that is very necessary for life-giving planets: a magnetosphere. Mars used to have a magnetic field that protected the planet. We found magnetized stones on the surface, suggesting that this was the case, but eventually the magnetic field disappeared and we do not know exactly what happened. Without a magnetosphere, the surface of the planet is bombarded with solar radiation, making life difficult for a larger, more complex life.
This "solar wind" blows off the Martian atmosphere as well. Even if we induce microbial life to produce oxygen and other gases, much of it will simply slip into space.
These images show various elements that elude the Martian atmosphere. From left to right, the images show how carbon, oxygen and hydrogen float into space.
Fortunately, these challenges are not insurmountable. In the short term, we will probably build dome-like habitats to protect ourselves, our cyanobacteria, and our new atmosphere from the solar wind. In the long run, NASA scientists have proposed placing a strong magnet in a fixed orbit between Mars and the Sun. This magnet redirects the solar wind and shields the Martian atmosphere. As microbial life continues to release oxygen and greenhouse gases into the Martian atmosphere, the planet will warm, the ice caps will melt into oceans, and Mars may become our second home.
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