14 DAY TRIAL // Methane is a rather unstable gas when exposed to sunlight, and it is easily broken up into its organic constituents after moderate exposure times, chemists say. Finding it on other planets is an equally difficult task for the same reasons, and that is why astronomers could not believe their eyes when it was clearly established that the moon Titan actually holds the hydrocarbon. How the body got its atmosphere was however another question, and one that researchers scratched their heads over for a long time. Now, they believe they might have come up with an explanation for the event.
While, back on Earth, methane is released in the atmosphere from humans, animal reflexes, volcanoes, hydrothermal vents, and some reactions between rocks and water, this is not the case on either Mars or Saturn's Titan, the only other two places in the solar system where the gas has been discovered. While, in the case of the Red Planet, the origins of the gas have recently been established not to come from any living organisms, Titan remains the grand prize. Its dense, nitrogen atmosphere is laden with methane, Technology Review informs.
The thing that has astronomers and geologists wondering is the origin of the gas. Given that sunlight constantly breaks it apart, and that observations revealed a somewhat constant concentration on the moon, it must be that an ongoing source of methane exists, which emits sufficient gas to replace the amounts broken up by the Sun. Excluding the possibility of microorganisms releasing it, experts are left with only two options – serpentization and methane ice.
The first concept refers to the possibility of the gas coming from ongoing reactions between iron or magnesium silicates, water and carbon dioxide at the surface of the moon, which produce methane. Similar processes have been observed in the Arctic regions of Canada as well, in rocks dating back from the Precambrian Age. Therefore, this is a distinct possibility. In the second theory, Titan's interior formed from methane ice in the early stages of the solar system, and heat now melts that ice, releasing the methane that was trapped inside over the last few billion years.
In a new, groundbreaking study on the ratio of hydrogen to deuterium on Titan, an international group of planetary scientists has determined that serpentization cannot explain the relations between the two chemicals, in the proportions they have on Saturn's moon. The team also reveals an ingenious mechanism of assessing if their idea is true. Given the fact that Enceladus was made of the same material, and that it occasionally spews out its contents outside its atmosphere, the Cassini spacecraft could run a basic test on these emissions and establish the isotopic ratio between hydrogen and deuterium.