January 29, 2025: Experimental Heating Of Complex Organics Demonstrates That Internal Activity Plays A Role In The Stability Of The Atmosphere Of Titan
A new study entitled "Experimental heating of complex organic matter at Titan's interior conditions supports contributions to atmospheric N2 and CH4", published in Geochimica et Cosmochimica Acta in the volume 390 of February 1, 2025 and proposed by a team of researchers involving Doctor Kelly Miller of the Southwest Research Institute reveals the potential role of the internal chemistry of Titan in the stability of its atmosphere. The largest moon of the Gas Giant Saturn is clearly a unique world in the Solar System due to its remarkable atmosphere that is deep and thick and that may resemble the atmosphere of the Early Earth. The atmosphere of Titan is in fact dominated by molecular nitrogen like the atmosphere of the Blue Planet. Nitrogen represents about 95 percent of the composition of the atmosphere of the giant moon which represents a higher fraction than that of nitrogen in our own atmosphere (around 78 percent). Oxygen that is widespread in our own atmosphere, representing about 21 percent of the composition, is absent or almost absent in the atmosphere of Titan. The atmosphere of that exotic world unveils a relatively high concentration of methane (around 5 percent of the composition at sea level).
How can we explain that Titan contains a significant atmosphere whereas most of the other moons in the Solar System are devoid of any atmosphere ? The largest moon in the Solar System that is to say Ganymede is devoid of any significant atmosphere for instance. Yet, that moon is relatively big and it evolves in a relatively cold environment around the Gas Giant Jupiter. A world like Mercury is also devoid of any significant atmosphere. Yet, Mercury is bigger than our moon, The Moon, but it evolves in a very warm environment around the Sun so that volatiles can more easily escape from the gravity of the planet. The presence of any atmosphere is in fact closely related to the factor of gravity and to the factor of environmental temperature. In principle, there must be the right combination of gravity and environmental temperature for the presence and the stability of any atmosphere. Worlds like Triton and Pluto contain a thin atmosphere. That configuration is probably related to the right combination of gravity and environmental temperature. Their gravity is particularly weak compared to that of the Earth but they evolve in an extremely harsh environment where the ambient temperature is much lower than that of the Earth.