Possibility of Life on Titan

Two recent studies of chemical data from NASA's Cassini's spacecraft suggest that Titan, one of Saturn's moons, may harbor life.

According to one of the studies, hydrogen in Titan's atmosphere is disappearing at the surface. This could mean that living things are consuming the hydrogen.

Scientists had expected hydrogen molecules, which would be formed when molecules of methane and acetylene in Titan's upper atmosphere were broken apart by ultraviolet rays from the Sun, to be distributed evenly throughout the moon's atmosphere.

Instead, researcher Darrel Strobel, at Johns Hopkins University in Baltimore, found that hydrogen was arriving at the surface at a very fast rate - approximately 10,000 trillion trillion molecules per second.

According to Strobel, hydrogen molecules are very light and do not easily react with other chemicals, so they should rise to the top of the atmosphere.

Another study showed that there is no acetylene on Titan's surface.

Scientist had predicted that interactions between the Sun and chemicals in Titan's atmosphere would produce acetylene, which would fall to the moon's surface.

However, a map of hydrocarbons on the surface showed that there is no acetylene there.

According to Chris McKay, an astrobiologist at NASA's Ames Research Center, acetylene would probably be the best source of energy for life that depends on liquid methane, instead of water, as a liquid medium.

Titan is too cold for water to exist in a liquid form there; life would have to depend on the few substances that are liquid at such low temperatures. These include liquid methane and similar substances, such as ethane.

It is far from certain, however, that these findings mean that life is present on Titan.

According to Mike Allen, the Astrobiology Institute Titan teams' principal investigator, it is very likely that these phenomena are the result of by non-biological processes.

Strobel suggests that the disappearance of hydrogen could be the result of an unknown mineral acting as a catalyst that encourages hydrogen molecules and acetylene to recombine to form methane.

Allen says that cosmic rays or sunlight may be converting the acetylene in the atmosphere into more complex chemicals.