You science fiction gurus out there will love this.
Back in 1997 when the Cassini space probe was launched, one of it’s major objectives was to study Titan — the largest moon of Saturn which is bigger then the planet Mercury and the only known satellite to have a substantial atmosphere. To better study the moon, Cassini carried along with it the Huygens Probe.
Scienetist were never exactly sure what they would find on Titan — sure it has a thick atmosphere rich in organic compounds, but could life take hold on Titan making use of some kind of chemistry that uses liquid methane as opposed to water? Scientists wanted to know. They known life, in the traditional sense, cannot survive on Titan, for one thing it’s too cold, liquid water cannot exist, but liquid methane can and an alien biology using liquid methane could serve the same function as water does on Earth.
Enter Christ McKay who devised a theory of what she be looked for in a methane rich environment that would be an indicator to alien life.
- Lower level of methane and acetylene, which would indicate some kind of alien metabolism, much like the waxing and waning level of CO2 in the summer and winter.
- A suspicious lack of hydrogen down on the surface, where such accumulations could be used as food.
Scientists already knew there wasn’t as much ethane in Titan’s atmosphere as they’d expected. If there had been, the moon would have been covered with an ocean of the stuff several meters deep and Cassini saw nothing of the kind.
So why the cause of all the excitement? Because now the Cassini space craft has satisfied the other two condition for a good indication of life on Titan: lack of acetylene in the atmosphere and a lack of hydrogen down on the surface.
The article referenced above and the scientists are quick to mention that this in no way proves the existence of life on Titan — that cannot be possible without direct observation. None the less, the possibility exists, and furthermore, this gives NASA and advocate of space exploration more ammunition to push for the exploration of the solar system and universe.
Further reading here.