The Astrobiologist’s Salvation: Extremophile Bacteria
The common trope of outer-space aliens has been a key topic in science fiction since the beginning of the genre. But could the imagined be real? What is the possibility of life in the great beyond, and how would it revolutionize biology and the chemistry of life as we know it? This blog post seeks to address the importance of Earth’s early history as a model of predicting how life could develop in space, the role of extremophile bacteria in outer space, and potential implications for humanity if we find organisms capable of surviving detached from the blue marble.
When we begin to look for signs of life in the universe, it helps us to understand the earliest history of life on our own planet. Scientists are generally in agreement that life started on Earth as a result of the gradual development of very simple life forms, microorganisms, from the chemistry resultant from meteor impacts. The dense iron impact created iron oxide which was able to decompose or rip the oxygen from water, leaving only behind hydrogen. Over time, the hydrogen formed a blanket over the Earth, creating a primitive atmosphere where the building blocks of complex life could begin to take form, like RNA and other amino acids.
Then there are three main conditions for life to develop. The first is water, the second is the existence of a suitable atmosphere, and the third is the presence of biological (carbon-based) material. So far, no conclusive evidence has been found to support the existence of the second and arguably most fundamental pillar - the suitable atmosphere. No other planet or space-mass has the capability to resist the vacuum of space, and because of the vacuum, close to no molecules - including water - can exist on the surface or surroundings of other planets.
While water has been confirmed to exist in small quantities on planets like Mars in the form of ice and vapor, the extreme conditions of the terrain and atmosphere render the water useless as a means of sustaining life.
Is the hope of extraterrestrial life dead, then? Well, no. Very recent scientific discoveries have implicated extremophile bacteria as one of the key players likely to support more complex life-forms on other planets. This specific set of bacteria, capable of resisting extreme pH, temperatures, radiation, salinity, and other conditions, are not subject to the same restrictions of environment as other life forms and thus have the capacity to transcend the barriers of water access, atmosphere, and carbon-based material that prevent planets from hosting life. Extremophile bacteria currently exist on Earth in the most remote and extreme places - the depths of the Mariana Trench, the absolute bottom of Antarctic ice plates, and the driest, saltiest parts of the Sahara.
The extreme resistance of extremophile bacteria naturally make them a good candidate for the prospect of introducing life on other planets. New research published by the Uniformed Services University of the Health Sciences in Maryland proves that organisms facing the very low temperatures characteristic of Mars (minus 80 degrees Fahrenheit) and exposure to UV and gamma radiation could survive for extreme lengths of time - up to 280 million years. Furthermore, bacteria could be the only microorganisms that could survive on the extremely sparse water deposits already confirmed to exist on Mars and other planets.
The prospect of growing extremophile bacteria colonies on planets like Mars is naturally appealing for humanity because of their importance in developing a future ecosystem. If the bacteria colonies grow to be self-sufficient and naturally replenishing, the atmosphere of these harsh environments would be stocked with carbon, nitrogen, and sulfur, which are the natural byproducts of bacterial activity. The introduction of extremophile bacteria would create a chain effect where bacterial decomposition would contribute to a stronger, more organic atmosphere, which would in turn promote more bacterial growth. This atmosphere could then become more suitable for terraforming purposes, making limited agriculture and human habitation possible.
Life in outer space certainly has to start somewhere, and the smallest options are also the most promising.
