Cassini Explores a Methane Sea on Titan

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Cassini Explores a Methane Sea on Titan

Post by bystander » Wed Apr 27, 2016 3:25 pm

Cassini Explores a Methane Sea on Titan
NASA | JPL-Caltech | Cassini | 2016 Apr 26
[img3="Sunlight glints off of Titan's northern seas this near-infrared, color mosaic from Cassini. (Credits: NASA/JPL-Caltech/Univ. Arizona/Univ. Idaho)"]http://www.jpl.nasa.gov/spaceimages/ima ... 432_ip.jpg[/img3][hr][/hr]
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.

Both Earth and Titan have nitrogen-dominated atmospheres -- over 95 percent nitrogen in Titan's case. However, unlike Earth, Titan has very little oxygen; the rest of the atmosphere is mostly methane and trace amounts of other gases, including ethane. And at the frigid temperatures found at Saturn's great distance from the sun, the methane and ethane can exist on the surface in liquid form.

For this reason, scientists had long speculated about the possible existence of hydrocarbon lakes and seas on Titan, and data from the NASA/ESA Cassini-Huygens mission does not disappoint. Since arriving in the Saturn system in 2004, the Cassini spacecraft has revealed that more than 620,000 square miles (1.6 million square kilometers) of Titan's surface -- almost two percent of the total -- are covered in liquid.

There are three large seas, all located close to the moon's north pole, surrounded by numerous of smaller lakes in the northern hemisphere. Just one large lake has been found in the southern hemisphere.

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. ...

Profile of a Methane Sea on Titan
ESA Space Science | Cassini-Huygens | 2016 Apr 26

Composition, Seasonal Change, and Bathymetry of Ligeia Mare, Titan,
Derived from Its Microwave Thermal Emission
- A. Le Gall et al The Bathymetry of a Titan Sea - M. Mastrogiuseppe et al http://asterisk.apod.com/viewtopic.php?t=33575
http://asterisk.apod.com/viewtopic.php?t=33755
http://asterisk.apod.com/viewtopic.php?t=33968
http://asterisk.apod.com/viewtopic.php?t=35711
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