Cassini Explores Methane Sea on Titan

Infrared image composite of Saturn’s moon, Titan. It has just been confirmed that this enigmatic moon is host to a vast sea of liquid methane

False-color image of Ligeia Mare, the second largest known body of liquid on Saturn’s moon Titan. The sea is filled with liquid hydrocarbons, such as ethane and methane with its seabed possibly covered with a sludge of hydrocarbons.

A new study released on 26 April, using data and images from the spectacularly successful Cassini mission to Saturn and Titan, has concluded that Saturn’s enigmatic moon Titan is host to a vast sea of pure, liquid methane, confirming wide-spread belief that such seas exist on Titan. It is also believed that this sea bed could be covered in a thick sludge of pure hydrocarbons and other carbon-and-nitrogen-rich compounds; as well, its shores may be surrounded by hydrocarbon wetlands.

Titan is thought to be similar to earth in its early nascent development phases where the right conditions for life to emerge and flourish were established. Of the hundreds of moons in our solar system, Titan is the only one with a dense atmosphere and large liquid reservoirs on its surface, making it in some ways more like a terrestrial planet.

An excerpt from the study describes how the radar imager aboard Cassini provided confirmation of what was widely believed to be true, the existence of vast seas of methane and ethane

The exact composition of these liquid reservoirs remained elusive until 2014, when the Cassini radar instrument was first used to show that Ligeia Mare, the second largest sea on Titan and similar in size to Lake Huron and Lake Michigan combined, is methane-rich. A new study published in the Journal of Geophysical Research: Planets, which used the radar instrument in a different mode, independently confirms this result.

Commenting further, Alice Le Gall, a Cassini radar team associate at the French research laboratory LATMOS, Paris, and lead author of the new study, describes the finding

“Before Cassini, we expected to find that Ligeia Mare would be mostly made up of ethane, which is produced in abundance in the atmosphere when sunlight breaks methane molecules apart. Instead, this sea is predominantly made of pure methane”

Launched in 1997 and arriving at Saturn seven years later, Cassini/Huygens has been one of the most visibly successful NASA/ESA missions. The Huygens probe, designed and built by the European Space Agency, was named in honor Christiaan Huygens, a prominent 17th century Dutch astronomer, physicist and mathematician who first observed Titan. Titan and the ethereal beauty of Saturn and its ring system can be observed first hand even in a modest amateur telescope.

In this now iconic image of Titan’s surface, one can see water-ice boulders the size of footballs along with the red, ruddy terrain of the moon’s surface.
This composite, composed of images acquired as the Huygens probe descended through Titan’s thick atmosphere, gradually reveals the emerging surface of the alien moon’s surface

The probe descended to Titan’s surface following the arrival of the Cassini/Huygens spacecraft to the Saturnian system at the end of June, 2004. The Huygens probe was dispatched to Titan while Cassini followed, eventually going into orbit around Titan. While in orbit, Cassini received and relayed the data, images and telemetry from the lander back to earth, having parachuted to the surface hours earlier. As the intrepid lander’s batteries ran down, it eventually fell silent with the mother ship Cassini in orbit overhead, eventually departing to begin its now brilliant mission at Saturn.

For the first time, humanity lands on the surface of an alien moon! Using the raw image data from the Huygens probe as it descended to the surface, an alien landscape unfolds before us. Additional images, composites and renderings from the original Huygens data can be found. One source is the German website Beugungsbild.

Continental lithosphere platform and small coastal zone of dry rivers on Titan. Icy crust, hills, and coastal zone of sub-glacial sea, islands and folding structures.

It’s a marvelous feat of exploration that we’re doing extraterrestrial oceanography on an alien moon

– Steve Wall, Cassini radar team deputy lead.

Imagination is more important than knowledge 585px-Albert_Einstein_signature_1934(invert)
An index of all articles in this blog can be found here.


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