Sea of ​​methane on Saturn’s lunar Titan could be more than 1,000 feet deep

Data collected by NASA’s Cassini probe allowed scientists to estimate the depth of Kraken Mare, the world’s largest methane sea on Saturn’s moon Titan.

New research published in the Journal of Geophysical Research expands our knowledge of the hydrocarbon seas of Titan, in particular Kraken Mare. This sea, about 600 miles (1000 km) long, is larger than the five Great Lakes of North America combined and contains about 80% of the moon’s surface liquids. The seas on Titan contain a lot of methane and ethane and are comparable to liquefied natural gas on Earth.

Titan is the only moon in the solar system known to host an atmosphere. The thick, nitrogen-rich blanket that covers the moon hides a complex hydraulic system on the surface, but instead of liquid water, Titan’s rivers, lakes, and seas are made of oily black methane. Titan also presents other curiosities, such as gigantic dust storms, ice volcanoes, and huge sand dunes.

As the new research shows, the deepest parts of Kraken Mare could be more than 1000 feet (300 meters) deep. TThe team, led by Valerio Poggiali, associate researcher at the Cornell Center for Astrophysics and Planetary Science, I can’t really be sure of this number, because the radar pings used to determine the depth of the sea never reached the seabed.

NASA’s Cassini spacecraft orbored Saturn of 2004 to 2017, and scientists already have studied some of the smaller seas on Titan using Cassini on board altimeter. On August 21, 2014, Cassini flew within 600 miles (970 km) of Titan’s surface and was able to send a radar pings in Kraken Mare. Interestingly, it is the same flyby that resulted in the discovery of Ligeia Mare – a “Magic” missing island on Titan.

Researchers at Cornell and NASA’s Jet Propulsion Laboratory have developed a neat technique for determining the depth of Titan’s seas, which involves measuring the differences between the time it takes for radar to bounce off the sea surface versus at the bottom of the sea. This technique makes it possible to estimate the depth of the sea, but researchers have to make some assumptions about the density of fluids on Titan and the speed at which radio waves pass through them.

Using this technique, the team measured the depth of Moray Sinus, an estuary north of Kraken Mare, which they found at 280 feet. (85 meters) deep. The absorption rate of radar waves suggests that the liquid in this part of the sea consists of 70% methane, 16% nitrogen, and 14% ethane. Scientists expected more methane than this due to the size and location of the sea, but this finding suggests a more even distribution of the chemicals across the moon’s various water bodies.

The altimeter scans carried out on the main part of Kraken Mare were less conclusive. As the authors write in the study, the NASA probe found “no evidence of returning signals from the seabed, suggesting that the liquid is either too deep or too absorbent for the radio waves to reach. Cassini can enter. That said, if the liquid in that part of the sea has a similar composition to the liquid found at Moray Sinus, then it must be deeper than 100 meters (330 feet). and possibly up to 300 meters (1000 feet), according to the study.

Poggiali is hoping that a robotic submarine could one day be sent to Titan to explore Kraken Mare or another body of water. And in fact, he sees the new research as a step in that direction.

“Thanks to our measurements, scientists can now deduce the density of the liquid with greater precision, and therefore better calibrate the sonar on board the [future robotic submarine] and understand the directional flows of the sea, ”explained Poggiali at a Cornell University declaration.

A conceptual plan from 2015 showed what such a mission might look like, but nothing has been approved in this regard. That said, NASA will send an aerial drone, called Dragonfly, to Titan, which is expected to land on the moon at some point in the mid-2030s.