Sapce.com on Titan Mountain Range

They think it was formed by plate tectonics. Titan is looking more and more like some kind of bizarro Earth and I am a lot less skeptical about finding some bizzare form of life there. Life exists on Earth wherever there is energy available suitable for use by organic catalysts. There are reasons to believe low feezing ammonia water solutions are present on Titan to form the basis for a soup of life and while the surface is very cold it is much warmer deeper down. Titan is showing a lot of characteristics rare in the solar system in common with Earth.

1) Abundant organic chemicals for use by life.

2) Dense atmosphere capable of protecting surface from impacts and radiation.

3) Dynamic atmosphere capable of supporting energy and mass transport cycles.

4) An atmosphere that is not in chemical equilibrium that can be used by life as a source of energy or might even be an indicator of life.

5) Plate tectonics providing long term sources of energy by replenishing materials that might be consumed on the surface.

6) Quite possibly a liquisphere at some depth

Yet another reason to spit on the parochial Earth centric definition of planet adopted by the IAU. Europa, Ganymede, Io, Titan, Triton and now even little Enceladus are as interesting as most of the planets. They are all probably more dynamic than Mercury and on a par with Venus or more active. Io is certainly the most dynamic terrestrial class world in the solar system. I think Bouie's general planet definition suggestion allowing large moons as secondary planets makes more and more sense.

If size alone matters Earth shouldn't be a planet from a gas giant standpoint. Planets much more massive than Jupiter have a similar size due to gravitational compresion of the planets' gas. It's only when you get to pathetic terrestrial planet masses that sizes start droping rapidly with mass. That's a significant phase change similar to deuterium fusion, hydrogen fusion, and enough mass to become round. There is no such significant change between Earth and Pluto. Pluto is bigger compared to Earth than Earth is to Jupiter.

Planets that aren't planets despite no significant change in mass until they clear their area is just a nonsensical excuse to make size matter in the case of Pluto. There is no way we are going to say extrasolar planets aren't planets in young systems because "they haven't cleared their local area' yet. Avoiding a definition consistent with extrasolar planets was a ridiculous and obvious crutch to find a desired outcome rather than a sound technical definition.

In the final analysis Titan, Europa, and Enceladus may be as critical to understanding life in the universe as the planet Mars and it's hard for me to consider such worlds insignificant compared to a lump of dead rock like Mercury.