The first geomorphological map of Titan’s surface has been made with infrared and radar data from the Cassini probe. Thus, thanks to the information acquired by NASA’s Cassini mission, we come across a more complete look at the mysterious moon. The new map, which has been published in the journal Nature Astronomy , offers new insights into how its methane cycle has shaped the surface.
How did they do it?
From 2004 to 2017, the Cassini spacecraft made more than 100 flybys of Titan before disintegrating at Saturn in 2017. Its incredibly thick atmosphere has always obscured most attempts to directly observe its surface. Instead, the map relies heavily on data collected by Cassini’s radar instrument, which could penetrate through the moon’s orange haze and glimpse the surface.
The report highlights six key different environments and how the methane cycle shapes them.
Just as water shapes Earth, below Titan’s frozen surface, methane that rains in, creates rivers and lakes, and then evaporates into the atmosphere. The combination of this cycle with winds, chemical reactions, and temperature differences creates complex environments across Titan.
” Our results show that Titan’s surface is dominated by sedimentary processes with clear latitudinal variation, with dunes at the equator, plains at mid-latitudes, and labyrinth terrain and lakes at the poles,” the authors explain.
There is a clear latitudinal variation between the different scenarios of Saturn’s moon : the dunes are near the equator, the organic plains are in the middle latitudes, and the poles are home to the famous methane lakes and peculiar labyrinthine terrains. The other two terrains are ancient hills and mountains called hummocky .
What does the map show?
The new map shows that most of the methane lakes, which make up about 1.5% of Titan’s surface, are located at the poles. Most of the lakes are at the north pole, and astronomers believe this could be an effect of Saturn’s elliptical orbit around the Sun, which lengthens the summer in the northern hemisphere and prolongs the rainy season for longer. creating more lakes.
In general, we could summarize the map in these data: plains, dunes, humid terrain, lakes, labyrinthine terrain and craters:
Methane lakes: 1.5% of the area
Flat plains in the middle latitudes and dry, sandy dune fields at the equator: 65% of the area
Very old hills and mountains : about 14% of the area
Valleys shaped by rain and erosion at the hands of the methane cycle: 1.5% of the surface.
Questions remain to be answered
Titan is like a strange Earth, which raises some really tantalizing prospects: could it harbor life? And how different would that life be, thanks to the moon’s unusual methane cycle? Could life thrive on Titan? Those are just a few of the questions NASA hopes to answer in the future.
The US space agency plans to return to Titan in 2034 for the Dragonfly mission, which will launch a drone on the surface of the moon. It will be NASA’s first flying vehicle to conduct a science mission to another world during an initial nearly 3-year study.
“The Cassini mission revealed that Titan is a geologically active world, where hydrocarbons such as methane and ethane play the role of water on Earth,” said David Williams, a co-author of the study. “These hydrocarbons rain on the surface, flow in streams and rivers, accumulate in lakes and seas, and evaporate into the atmosphere. It’s an amazing world! “
We will have to wait for Dragonfly to search the surface of Titan for possible signs of life.
Referencia: R. M. C. Lopes, M. J. Malaska, A. M. Schoenfeld, A. Solomonidou, S. P. D. Birch, M. Florence, A. G. Hayes, D. A. Williams, J. Radebaugh, T. Verlander, E. P. Turtle, A. Le Gall and S. D. Wall. “A global geomorphologic map of Saturn’s moon Titan”. Nature Astronomy , 18 de noviembre de 2019.
