Is There a Subsurface Water Ocean On Titan?

Stirling Newberry writes "Luciano Iess and team have hypothesized that Titan joins Earth, Europa, and Ganymede as ocean worlds. They measured the size of the tidal bulges and found that the moon is likely not solid (abstract). Team member Jonathan Lunine points out that Titan's methane atmosphere is not stable, so it needs some source, perhaps from outgassing. On Earth, water means life, and in the future, ice covered ocean worlds are targets for human colonization. As the late Arthur C. Clarke observed, water is the most precious substance in the universe to humans."

Re:Betteridge's Law of Headlines

[docmordin]

It most likely is an exception.

The idea of a subsurface ocean on Titan is nothing new and surfaces in the geophysics/geoscience literature every so often. For example, when Voyager I passed by the moon, it detected an abundance of only 3% (mole fraction) of CH4, which is sufficiently low to preclude the stable coexistence of liquid CH4 on the surface. Lunine, et al. ("Ethane ocean on Titan", Science, 222, 1229-1230, 1983) suggested that Titan's atmospheric CH4 may have broken down by a catalyzed photochemical reaction to C2H6, with the C2H6 stemming from a subsurface ocean; the resulting deep ocean would consist of a 3:1 mixture of C2H6 and CH4. (To explain, the dissociation steps of C2H6 involve loss of hydrogen by escape, with the postulated set reactions: 2CH4 -> C2H6 + H2 and 2CH4 -> C2H6 + 2H. The intermediate molecule C2H2 plays the role of catalysis and shielding of C2H6 from photolysis. Furthermore, CH4 would break down at a rate of 1.5*10^10cm^-2/s and H/H2 would leave the atmosphere at 5.5*10^9 and 7*10^9cm^-2/s, which is consistent with Hanel, et al.'s analysis ("Infrared observations of the Saturnian system from Voyager I", Science, 212, 192-200, 1981). As such, it is reasonable to conclude that the result is a production of an CH4-rich ocean of 1km depth and a 100-200km thick layer of solid C2H2 on Titan's ocean floor).

For additional analyses, see: F. M. Flasar, "Oceans on Titan?", Science, 221, 55-57, 1983; O. B. Toon, et al., "Methane rain on Titan", Icarus, 75, 255-284, 1988; N. Dubouloz, et al., "Titan's hypothesized ocean properties: The influence of surface temperature and atmospheric composition uncertanties", Icarus, 82, 81-96, 1989; W. R. Thompson, et al., "Vapor-liquid equilibrium thermodynamics of N2 + CH4: Model and Titan applications", Icarus, 97, 187-199, 1992.

FYI:Betteridge's Law of Headlines

[camperdave]

Betteridge's Law of Headlines is an adage that states, "Any headline which ends in a question mark can be answered by the word 'no'".