Comparison Essay

Humans have always thought about the possibility of extra-terrestrial life forms. Titan is the largest moon of Saturn, and was first discovered in 1655 by Christiaan Huygens. It is slightly smaller than Mars and only receives only 1 percent the sunlight that Earth does (Space 2009). However, it is the only moon in the solar system that has a fully developed atmosphere and has many similarities to Earth, but also many differences. Titan’s thick atmosphere has led people to believe it may be able to support life. In this essay the similarities and differences between Earth and Titan are researched, and the reasons that Titan is believed to be able to support life are discussed.

Titan is the only object in the solar system apart from Earth that

Due to this, Earth has rivers, lakes, rain and oceans of water, and this molecule is believed to be necessary for life to exist. Titan has water on the surface, however due to the extremely cold temperatures it only exists as solid ice. These extreme temperatures allow for methane to exist in a triple point instead. This results in methane rain and lakes all over the surface of the moon (Astronomy 2009). Beside from Earth, Titan is the only place in the solar system that has a stable liquid on its surface (Jet Propulsion Laboratory 2013). The hydrocarbon lakes have an extreme longevity, which leads scientists to believe the lakes are liquid ethane as it evaporates much slower than methane (Jet Propulsion Laboratory 2013). The lower atmosphere has two distinct layers and is known as the boundary layer (Anderson 2012). This layer is the most influential on climate and weather (Anderson 2012). Ice on Titan is the equivalent of rock on Earth, and winds break down this ice into particles that are similar to sand (Carroll 2006). Dunes are formed and spread across regions up to 1500 kilometres long and are similar to the dunes found on Earth (Carroll 2006). Scientists did not expect to see winds strong enough to form these dunes, due to the low solar heating caused by the distance Titan is from the sun (Carroll 2006). However, the circulation of Titan’s atmosphere is

These are a suitable temperature range to allow chemical bonding, and an energy source such as the sun or radioactive decay (SpaceRef 2004). Professor Benner also states that hydrocarbon solvents are better for managing complex organic chemical reactivity than water (SpaceRef 2004). Astrobiologist William Bains suggests that all life requires a liquid (Astronomy 2010). As water on Titan is frozen solid, Baines says that “…if life were to exist on Titan, it must have blood based on liquid methane, not water," (Astronomy 2010). According to Bains, a lot of energy is required for rapid movement or growth, and so only slow growing organisms are possible in theory (Astronomy 2010). An international team of scientists simulated Titan’s atmosphere and observed the creation of amino acids and the five nucleotide bases which are required for life on Earth (Andrews 2011). The moon’s surface may not be able to support these reactions due to the cold temperatures; however, the upper atmosphere’s radiation, sunlight and other energy are likely able to create the environment needed for the compounds to be created (Andrew 2011). Scientists suggest that the organic haze in the atmosphere of Titan is similar to the haze in early Earth’s air (Astronomy 2006). This haze may have aided life form on Earth (Astronomy