Antonio Manaytay – Fourth Estate Contributor
Ithaca, NY, United States (4E) – The new global map of Titan has offered a glimpse on the terrain how the liquid flows in Saturn’s Largest Moon. At the same time, it has raised more questions on how its polar basins evolved.
In papers published in Geophysical Review Letters, the Cornell astronomers created the map for almost a year from the complete data of the Cassini mission combining all the topographic data of Titan from multiple sources.
Doctoral student Paul Corlies, first author on “Titan’s Topography and Shape at the End of the Cassini Mission,” said the map was created primarily for the use of the scientific community.
After the map was made available online, Corlies said he received several inquiries how to use it.
Several features of the new map include new mountains no taller than 700 meters. The high and low views of Titan’s topography have confirmed that the two regions along the equator are depressions which could be seas that dried up or cryovolcanic flows.
The map shows Titan is more oblong in shape than previously thought.
Another paper entitled “Topographic Constraints on the Evolution and Connectivity of Titan’s Lacustrine Basins” suggests that Titan’s seas formed a sea level just like what Earth’s oceans do due to the existence of sub-surface flow between the seas.
“We’re measuring the elevation of a liquid surface on another body 10 astronomical units away from the sun to an accuracy of roughly 40 centimeters,” Alex Hayes said.
“Because we have such amazing accuracy we were able to see that between these two seas the elevation varied smoothly about 11 meters, relative to the center of mass of Titan, consistent with the expected change in the gravitational potential,” Hayes said.
Titan’s lakes are connected with each other, a confirmation of Hayes’ graduate paper. These liquid-filled lakes are located above the sea level and dried up lakes are situated higher than the liquid-filled lakes nearby.
“We don’t see any empty lakes that are below the local filled lakes because, if they did go below that level, they would be filled themselves,” Hayes said, adding that this indicates that “there’s a flow in the subsurface and that they are communicating with each other.”
“It’s also telling us that there is a liquid hydrocarbon stored in the subsurface of Titan,” he added.
Hayes’ team had also revealed new mystery as the new map indicates that most of the lakes are on top of sharp-edged depressions looking “like you took a cookie cutter and cut out holes in Titan’s surface.”
These lakes, Hayes said, have rims about hundreds of meters high in other places which could indicate that the borders of these lakes keep on expanding, a process known as uniform scarp retreat.
“But if these things do grow outward, does that mean you’re destroying and recreating the rims all the time and that the rims are moving outward with it,” Hayes asked.
He believed understanding how these rims are created or formed is “the lynchpin to understanding the evolution of the polar basins on Titan.”
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