NOTE: This post was originally published on our parent site, futurestica.com (http://futurestica.com/blog/2017/04/01/titan-habitablezone/)
Titan is undoubtedly one of the most interesting places in our solar system. It is the only moon in the solar system to have an atmosphere.
Discovered by the Dutch astronomer Christiaan Huygens in the 17th century and further studies by pioneers of astronomy like Josep Comas i Sola and Gerard Kuiper, this moon is a hydrocarbon mega-factory, producing millions of tones of methane, ethane, acetylene and other wide range of compounds from sources that are still unknown to us.
While the Cassini spacecraft approached this mysterious moon on 2 December 2004, it relayed back data showing that Titan was in fact a world so similar to Earth. It was found to have oceans, seas, lakes and rivers of liquid hydrocarbons and even clouds, which hinted that it often rained on Titan.
Right from then, many speculations about methane super-bugs swimming in the liquid lakes of Titan came from scientists and science fiction writers alike.
In 2005 astrobiologist, Chris McKay of NASA’s Ames Research Center published a paper along with Heather Smith of the International Space University in Strasbourg in which they describe how methane-based life forms on Titan (‘methanogens’) could consume hydrogen, acetylene and ethane and exhale methane instead of carbon dioxide. They also mentioned that if such a life form ever existed, it could reveal itself through a depletion of hydrogen acetylene and ethane on the surface. Amazingly, this depletion was observed on Titan but scientists including McKay himself are dubious that some other unknown physical process on the moon might be causing it.
Nevertheless, the most important realization is not whether or not methane super-bugs exist or not but that life does not always need the conventional environmental conditions and compounds (Oxygen and Water) for its existence. Organisms that do not need oxygen are quiet familiar to us. These include yeast and the bacteria used in the process of fermentation.
However, we still have no evidence of any organisms that does not require water for their survival. This is because water is a universal solvent and has immense importance in the multiplication of DNA molecules and life as we know it always contains DNA or some other similar genetic material at the molecular level.
But what happens in temperatures below or above the freezing and boiling points of water? We previously taught that life would be impossible in such subfreezing and ultra-boiling temperatures. However, new findings have shown that at these conventionally inhospitable conditions some compound other than water could act as a solvent, thereby enabling life to thrive in a much wider range of environmental conditions than previously taught.
|A graph showing the habitability of different stars.|
If we ever find life on Titan, it would exponentially increase the chances for finding alien life beyond the solar system as it will point out that life can also exist beyond the liquid water habitable zone (i.e. the conventional Goldilock zone that we presently use for the classification of habitable exoplanets.) around other stars.
It would rather create a mess in exobiological records because we won’t be having a clear definition for a habitable zone, life could in fact exist everywhere, on any planetary surface and sometimes it might not even need a surface for survival. Sometimes organisms would be floating on the upper atmosphere of gas giants by carrying with them sacks of hydrogen of helium gases that would enable them to float in the air, sucking in nutrients from the gas giant’s diverse atmosphere. Sometimes, they may even prey on other organisms for their helium reserves or even for food.
|An artist speculation of life in a Jupiter like gas giant planet.|
Nevertheless, these are all speculations that could only be proven by the exploration of this mysterious alien world, Titan. This frigid moon holds the secrets that could sometimes make scientists rewrite the principles of astrobiology. We don’t know until we conduct another close up exploration.
Read more about the deep unsolved mysteries of Titan in our new book, ‘The Worlds Unknown’ (Click here to get the book).