By Alex Stuckey
By Alex Stuckey
Oceanographers may need to study alien worlds sooner than you think.
Observations by NASA‘s Cassini spacecraft indicate Saturn’s moon Titan is more Earth-like with its dense atmosphere, lake-filled surface and possible wetlands.
Other than our home planet Titan is the only known world in the solar system with stable liquid on its surface, according to NASA.
Since 2004, Cassini has found more than 620,000 square miles of Titan’s surface covered in liquid, about two percent of its globe. Planetary scientists have theorized about what elements fill Titan’s liquid bodies, but thanks to Cassini they now have answers
A new study using Cassini’s radar instrument to study Titan’s second largest sea, known as Ligeia Mare, between 2007 and 2015 reveals it’s a filled with methane.
The study published in the Journal of Geophysical Research: Planets confirms what planetary scientists have thought about Titan’s seas for some time.
Using Cassini’s radar instrument to detect echoes from the seafloor of Ligeia Mare scientists used the depth-sounding information to observe temperatures, which helped give clues to their composition, according to the news release.
“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,” said Alice Le Gall, a Cassini radar team member and lead author of the new study.
Ligeia Mare is the about the size of Lake Huron and Lake Michigan together, according to NASA and from Cassini’s flybys scientists were able to determine the sea is 525 feet deep in some areas.
All of Titan’s seas are named for mythical sea creatures. The largest sea, Kraken Mare is about 680 miles long.
Another similarity between our home planet and Titan is they both have nitrogen atmospheres, but Titan is lacking much oxygen. Titan’s atmosphere is mostly methane with trace amounts of ethane and because of the distance from the sun, meaning cold temperatures, the methane and ethane remain in liquid form instead of escaping, according to NASA.
Le Gall offered a few possibilities of how Ligeria Mare became mostly methane filled, instead of ethane as Cassini’s team originally thought.
“Either Ligeia Mare is replenished by fresh methane rainfall, or something is removing ethane from it,” said Le Gall. “It is possible that the ethane ends up in the undersea crust, or that it somehow flows into the adjacent sea, Kraken Mare, but that will require further investigation.”
The study also found Ligeia Mare’s shoreline may warm quicker than in the sea, similar to a beach on Earth.
“It’s a marvelous feat of exploration that we’re doing extraterrestrial oceanography on an alien moon,” said Steve Wall, deputy lead of the Cassini radar team. “Titan just won’t stop surprising us.”