The search for extraterrestrial life on Titan has recently been reinvigorated by the discovery of a chemical trail suggesting the possible presence of life forms on the largest moon orbiting Saturn. This new discovery is the latest evidence for living beings, in whatever form they may be found, on the giant satellite.
Water is an essential component for life on Earth, and many people searching for life on other planets search for the universal solvent, in order to judge the chances of finding life on the body. However, new research suggests water may not be as vital to the hunt for alien life as previously believed. It is possible chemicals produced on Titan could reduce, or eliminate, the need for water in the formation of life.
"Titan is the only other body in the solar system, aside from Earth, that has flowing liquids on its surface. Moreover, hydrogen cyanide, a key prebiotic molecule, exists there in ample amounts, as it likely did on the early Earth," Martin Rahm, a quantum chemist working at Cornell University, said.
This is not the first time astronomers have seen enticing evidence for the possibility of life on the alien surface of Saturn's largest moon.
Astronomers have known for a long time that Titan contains in vast quantities hydrocarbons, far exceeding the total petroleum reserves here on Earth, hundreds of times over. This amount is especially striking considering the fact that Titan is only about the size of the planet Mercury, or around 50 percent greater than the diameter of our own moon.
Hydrocarbons evaporate from the surface of Titan, and precipitate back down, forming vast oceans of ethane and methane. This process suggested, early on, to astronomers that complex reactions of organic materials could be taking place on the moon, perhaps even forming life. Dunes of solid carbon-based materials, called tholins, are seen near the equator of Titan. Some astrobiologists suggest these deposits could be essential in the development of life on the frigid satellite.
"We are carbon-based life, and understanding how far along the chain of complexity towards life that chemistry can go in an environment like Titan will be important in understanding the origins of life throughout the universe," said Ralph Lorenz of Johns Hopkins University.
Titan's atmosphere, like that on Earth, is mostly nitrogen. However, unlike the air we breathe, the atmosphere of Titan is also rich in methane.
Despite the possibility of complex organic reactions on the massive satellite, this moon is extremely cold, reaching temperatures as low as 300 degrees below zero Fahrenheit. Liquid water on Earth also plays an important role in the formation of DNA and proteins, in part due to the molecular structure of the liquid.
The Cassini spacecraft has been in orbit around Saturn since 2004, gathering data on the massive planetary family. That mission is scheduled to end in 2017, limiting the time astronomers have to find definitive evidence of life on Titan while utilizing the observatory currently in place.
NASA has recently announced a new contract aimed at developing an aerobot, capable of exploring the atmosphere, oceans and landforms of Titan.
