The assumption of old age concerning Titan and the predictions that proceeded from it, here are the facts, they were wrong about a global ocean; they were wrong about huge lakes of liquid ethane; they were enormously surprised to discover sand dunes on Titan but what about geology?
They are still gathering data from this amazing moon, and once again it doesn’t look good for old age assumptions. Scientists hoped to find volcanoes but a new paper concludes that Titan gets its geology from the outside, instead from the inside. If this is found to be true then its implication consists of the surface features being created by wind, impacts and weather rather than active geology.
The hopeful cryovolcano announced last year was challenged by Moore and Pappalardo, authors of the new paper. Could the evidence be pointing to a geologically dead world on Titan? Planetary scientists previously have had an age conundrum with Titan. They know that the methane in the atmosphere is destroyed and converted to other compounds in a one-way process. This puts limits on the age of the atmosphere which indicates a far less 4.5-billion-year age assumed for the solar system. This is why they hoped to find a reservoir of methane under the surface which would erupt in cryovolcanoes to replenish the atmosphere.
In another paper from the same source, it analyzed Titan’s equatorial sand dunes. These dunes, covering about 12.5% of the surface, were a surprise when discovered, because scientists were expecting large lakes or even a global ocean. Scientists also doubted that the winds were strong enough at the surface to move particles around. Dunes also exist on Mars, Venus, and of course, Earth, but on Titan, the average 300-foot-high dunes are nearly1.9 miles apart, and getting farther apart at higher latitudes.
Unlike the silica sands on Earth, the particles in Titan’s dunes are thought to be composed of hydrocarbon dust and ice precipitated out of the atmosphere. All together, they constitute the largest known reservoir of organics on Titan, because the combined area of dunes is about as large as the United States. The dunes infringe upon the theories of Titan’s age. Because for one, they are among Titan’s most youthful features; for another, they indicate a lack of persistent liquid on Titan’s equator, even though liquid ethane should have been raining onto the surface throughout Titan’s history!
The presence of dunes implies that much of Titan is extremely dry. If spread out evenly over the globe, the particles in this largest reservoir of organics (larger than all the observed lakes combined) would fail to cover Titan with the predicted accumulation of hydrocarbons that must have been produced in the assumed 4.5-billion-year age of the moon.