[stephth]

Please forgive my ignorance. What makes Europa more likely to contain life than other moons thought to contain oceans like Callisto, Ganymede, Titan, Enceladus ... ? [1]

[1] http://img.gawkerassets.com/img/18lqil4sqeremjpg/original.jp... [2]

[2] http://io9.com/5827649/a-map-of-all-the-water-in-the-solar-s...

[InclinedPlane]

Titan is known to contain oceans, but of nearly cryogenically cold hydrocarbons. It's unlikely to support life merely due to the temperatures there.

Many planetary bodies are thought to have sub-surface water oceans of some variety, though Europa's is the most intriguing for several reasons. Given that Europa's surface is entirely water ice and geologically quite young that is a strong indication that Europa's sub-surface ocean is vast, warm, and consistently liquid over geological time periods. If, for example, Ganymede's ocean were as large and as warm then why has it not risen to the surface and formed an ice layer? This is backed up by the fact that Europa experiences an intense amount of tidal heating from it's galilean moon neighbors.

Because of this high amount of tidal heating, which on the neighboring moon Io is sufficient to cause widespread vulcanism, there is a reasonably good chance of significant hydrothermal vent systems within the Europan ocean. We've found on Earth that such vents can support chemotrophic life (through sulphides and serpentinization) which can support complex ecosystems which include animals such as shrimp and clams.

That isn't to say that other bodies may not harbor substantial sub-surface oceans or support extra-terrestrial life, but the case for Europa is that much stronger and so that much more a compelling target for investigation.

[maaku]

Enormous oceans of liquid water, with internal tidal heat and protection from harsh surface environment?

[ep103]

And lets not forget the large black monolith.

[trekky1700]

And this is why NASA's Planetary Sciences division should not suffer huge budget cuts.

[dmead]

read the 2010 novel by authur clarke. he goes into some detail about how it might work

[rsynnott]

I believe there's more evidence for an ocean in Europa than the other Galilean moons, and the ice sheet on top is thought to be substantially thinner. As for the moons of Saturn, I suspect Enceladus gets less interest simply because it's far less accessible, and if Titan has life it won't be remotely like any sort of life we're used to, and may be quite difficult to detect.

[vacri]

Because modern science is Eurocentric? :p