Titan – A moon of Saturn: What is so special about Titan and it's composition
Titan itself is a moon of Saturn and it Orbits at a mean distance of 1,221,870km. It is about 0.4 times the size of the Earth at just over 2570km, however it only has a density of 0.0225 times that of Earth at about 1.3452x1023 kg. This tells us that it's bulk composition is much less dense than that of the Earth.
A very interesting fact is that it is the only other body in the Solar system with stable liquid bodies at the surface and this is what is so fascinating, what does it mean, what is the liquid, how did they form, could they support life?
One of the theories of the internal structure of Titan
Composition of the moon of Saturn
For those of you that don't know, satellite is another word for moon. So what is special about Titan and how is it composed. As we have already said it is the only other body in the solar system with stable liquid at the surface, it is also the only Satellite to have a fully developed atmosphere consisting of complex compounds. It's composition is approximately 98.4% Nitrogen, 1.4% Methane and 0.2% Hydrogen as well as traces of more complex hydrocarbons.
Titan itself has four layers:
A Rocky core composed of mainly silicate rocks. NB// Recent interpretations of gravitational measurements of Titan lead us to believe that the core may actually be a slushy mix of ice and rock. This would most likely have occurred because the planet never got warm enough to fully differentiate.
A high pressure ice section, very little at the present time is known about this layer.
A liquid layer which most likely has a composition of ammonia and water, with the ammonia allowing the water to stay liquid to temperatures as low as-97 centigrade.
The surface layer of Ice, this has features similar tot that of Earth; with bodies of stable liquid, dune like structures, volcanic features (cryovolconism). Titan has some varied geology including surface features which seem to wander across the face of the planet, which as you can probably imagine is slightly unusual, this leads us to the fact that the surface must be completely isolated from the core by the fluid layer giving rise to a free floating crust. As this would allow free rotation of the surface.
Great Books on Saturn and Titan
Atmosphere on Titan
The atmosphere has fully developed which is fascinating in itself. Methane condenses out of the atmosphere above the Tropopause which is at about 35km. This leads to a rise in concentration of methane from here down to about 8km where it settles to about 4.9% which allows clouds to form. If you look at pictures of Titan you will see that it has an orange Haze and this cannot be explained by its composition. So what can explain it? Well the answer is that small quantities of complex chemicals called Tholins are present, these are created when methane reacts with ultraviolet light. Another strange aspect of the atmosphere is that this reaction should have meant that all the methane in the atmosphere should have been converted. However this has not occurred, why. Well it is clear that there must be a source of replenishment on Titan and it is likely that the process responsible for this is cryovolconism.
Huygens Descending through Titan's atmosphere
Titan is a geologically active planet and one with many exciting features some of which are explained in the following hubs.