Cassini Data Reveals New Insights Into Titan’s Seas

Eddie Gonzales Jr. – MessageToEagle.com – A recent analysis of Cassini-Huygens mission data reveals new information about the composition and behavior of Titan’s liquid hydrocarbon seas near its north pole. Titan is Saturn’s largest moon.

Credit: Pixabay/CC0 Public Domain

A Cornell University-led team used bistatic radar data to analyze the composition and roughness of Titan’s sea surfaces separately, improving upon previous monostatic radar analyses. This advancement will aid future studies of Titan’s seas using Cassini data.

A bistatic radar experiment involves a radio beam from the spacecraft at Titan, which then reflects it toward Earth’s receiving antenna.

This surface reflection is polarized—meaning that it provides information collected from two independent perspectives, as opposed to the one provided by monostatic radar data, where the reflected signal returns to the spacecraft.

“The main difference, is that the bistatic information is a more complete dataset and is sensitive to both the composition of the reflecting surface and to its roughness.” said Valerio Poggiali, research associate at Cornell University, and lead author of the study, in a press release.

The current work used four bistatic radar observations, collected by Cassini during four flybys in 2014—on May 17, June 18, Oct. 24 and in 2016—on Nov. 14. For each, surface reflections were observed as the spacecraft neared its closest approach to Titan (ingress), and again as it moved away (egress).

The team analyzed data from the egress observations of Titan’s three large polar seas: Kraken Mare, Ligeia Mare and Punga Mare.

Their analysis revealed varying compositions in the hydrocarbon seas’ surface layers, based on latitude and proximity to rivers and estuaries.

The southernmost part of Kraken Mare has the highest dielectric constant, indicating its reflectivity to radio signals. While water on Earth has a dielectric constant of about 80, Titan’s ethane and methane seas measure around 1. 7.

The researchers found the seas were generally calm during flybys, with waves under 3. 3 mm. Slightly rougher conditions up to 5. 2 mm were observed near coasts, estuaries, and straits, potentially indicating tidal currents.

“We also have indications that the rivers feeding the seas are pure methane,” Poggiali said, “until they flow into the open liquid seas, which are more ethane-rich. It’s like on Earth, when fresh-water rivers flow into and mix with the salty water of the oceans.”

Poggiali also said that ongoing analysis of Cassini’s 13-year Titan data continues.

“Much of this data remains to be fully explored, likely leading to more discoveries,” he added. “This is just the beginning.”

Paper: Surface Properties of the Seas of Titan as Revealed by Cassini Mission Bistatic Radar Experiments, Nature Communications (2024). DOI: 10.1038/s41467-024-49837-2

Written by Eddie Gonzales  Jr. – MessageToEagle.com Staff Writer