TITANTitan is Saturn's largest moon and the second largest observed satellite in the galaxy, just behind Ganymede but larger than Mercury [1]. It is the only satellite in the solar system to have a significant atmosphere that contains more than just trace elements. It is interesting for astronomers to see how an atmosphere can form and how abundances of certain compounds can appear without biological activity. [2] Titan may be suitable for certain types of biology and is analogous to Earth in many ways. When Titan was first observed, it was thought to be the largest satellite in the solar system. Images taken of Titan did not take into account the atmosphere, so it was considered part of the satellites' radius. The atmosphere is denser than the Earth: 1.5 bar at the surface. Combined with the planet's low gravity, this thick atmosphere would make aeronautics very efficient if humans colonized Titan, even allowing us to flap our "wings" and fly. [4]The atmosphere appears as a dark orange haze above the surface. The main constituent, as on Earth, is Nitrogen (92% on Titan and 78.08% on Earth) [5] and contrast Jupiter and Saturn whose atmospheres are mainly made up of Ammonia (NH3). Haze itself is composed of long-chain hydrocarbons that one would not expect to find in the Titans' atmosphere. Titan's atmosphere is very turbulent like those of Jupiter and Saturn, so we can assume that the atmosphere is well mixed. Being well mixed, one would expect the atmosphere to be in chemical equilibrium, and if this is true the only hydrocarbon found should be methane with traces of other hydrocarbons, but this is not true in the mist of Titan. In terms of life, one of the conditions is... middle of paper ...... grow food (like plants), photosynthesis would not be a viable method, so other sources of energy would be required. Other forms of life? If Titan does not appear to be a suitable environment for carbon-based life, can any form of life be supported? One of the most suitable candidates is silicon-based life with methane as a solvent.[1] - http://web.archive.org/web/20051202030828/http://saturn.jpl.nasa.gov/news/features/saturn-story/moons.cfm[2] - Rothery, David A. "Titan" . An introduction to astrobiology. Rev.2011 ed. Cambridge: Cambridge University Press, 2011. 171 - 198. Print.[3] -[4] - http://what-if.xkcd.com/30/[5] - http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html[6 temp] - Darnell, James E., Harvey F. Lodish and David Baltimore. Molecular cell biology. 4th ed. New York: Scientific American Books:, 1990. Print.