NASA's Cassini has discovered that a massive sea on Saturn's moon, Titan, is made up of genuine liquid methane, confirming previous similar investigation results.
The spacecraft was able to specifically explore the sea called Ligeia Mare, which seabed is believed to be covered in a goo of materials that contain high levels of nitrogen and carbon. Experts also think that the shores may be covered in wetlands.
Titan is the only moon in the solar system with a dense atmosphere and large areas of liquid on the surface. Such characteristics make experts compare it to a terrestrial planet.
With its very cold temperatures due to Saturn's distal space from the sun, experts believe that methane and ethane can be present on the moon's surface in liquid state.
With this, scientists have long assumed that hydrocarbon bodies of water exist on Titan. Data from NASA's Cassini spacecraft confirmed this as it has shown that more than 620,000 square miles or nearly 2 percent of Titan's total surface is topped with liquid.
Focus On Ligeia Mare
Titan has three big seas, which are all situated near the north pole, while one lake is located in the south.
Ligeia Mare is the second largest sea on Titan and is the first big liquid reservoir explored by Cassini in 2014. Data from the spacecraft suggest that the said sea is filled with methane and in a newly released study, this hypothesis was finally confirmed.
"It's a marvelous feat of exploration that we're doing extraterrestrial oceanography on an alien moon," says Cassini's Steve Wall.
Prior to the research, the team believed that Ligeia Mare is comprised of ethane, which is generated immensely in the atmosphere when the sunlight disintegrates methane molecules apart, says Alice Le Gall, the lead author of the new study. However, the new study revealed that the sea was composed of pure methane.
There are numerous reasons that can be attributed to the methane composition of Ligeia Mare, says Le Gall. One potential explanation is that fresh methane rainfall may replenish the sea. Another possibility is that something might be removing ethane and ends up in the crust beneath the sea or flows into the nearby Kraken Mare - something that needs additional investigation.
The study used data obtained during Cassini flybys to Titan from 2007 to 2015. The team also used information about the heat emitted by Ligeia Mare during a 2013 experiment, which has identified echoes from the floor of the sea.
The study was published in the Journal of Geophysical Research.