The History of the Mysterious "Island" on Titan, Saturn's Largest Moon (5 photos)

Here are three radar images of the same coastal region of Ligeia Mare, a hydrocarbon sea on Titan, Saturn's largest moon. The images were acquired by NASA's Cassini spacecraft in 2007, 2012, and 2014.





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The first image, taken in April 2007, was a control image. Nothing unusual. But in the second image (July 2012), a bright spot suddenly appears—as if a piece of land had been exposed from beneath a liquid. By August 2014, its appearance had changed: the object had become much dimmer, but it had also doubled in size, expanding from 75 to 160 square kilometers.

What is it?

In an attempt to explain this "something," scientists have put forward three hypotheses:

We are likely dealing with sea level fluctuations (tides). The drop in the level of these "reservoirs" leads to the partial exposure of material that is usually hidden under a layer of liquid hydrocarbons.

Could these be local waves? This hypothesis failed, as subsequent observations showed that the wave height on Titan does not exceed a centimeter.

NASA linked the anomaly to the formation and destruction of unusual icebergs. The Ligeia Sea consists of liquid hydrocarbons—primarily methane. Titan's surface temperature is approximately -179 degrees Celsius, allowing methane and ethane to exist in liquid form. However, during seasonal cooling or pressure changes, these organic compounds freeze, forming floating blocks—analogs of icebergs on Earth. The process can begin around crystallization centers—solid particles trapped in liquid: dust grains from the atmosphere or rock fragments from the shore. Ice grows around these "seeds," forming massive structures. But as temperatures rise, this natural formation begins to collapse, as we see in the third image (the bright peak has disappeared, and the massive base has "moored" to the shore).

My Explanation

Titan is a layer cake. The surface rock and "reservoirs" rest on a thick layer of ice, beneath which lies an ocean of liquid water.

This entire complex and rather mobile structure orbits the giant planet Saturn, whose gravitational pull generates tidal forces that distort the moon's shape. During these "tides," Titan's surface can rise and fall by a significant 10 meters.

A closer look at the images from 2007 and 2014 reveals changes across the entire coastal region. I've highlighted the most noticeable transformations in yellow:





Titan's seas and lakes are relatively shallow bodies of water, with a maximum depth of about 300 meters. Naturally, this depth is much shallower near the coast, so during high tide, when the ice layer rises, it becomes visible from orbit. These uplifts fragment the ice at its weakest points, causing its layers to interact with each other like lithospheric plates on Earth. Each such tidal action reshapes the moon's surface, as we see in Cassini images.

Further Research

In July 2028, NASA's Dragonfly mission, a drone-helicopter, will launch to Titan to explore the moon's surface from a bird's-eye view. One of its main objectives is to study Titan's seas and lakes.

So, in the foreseeable future, we will likely learn precisely what caused the anomalous changes in Ligeia Mare.

Read also:

10 Interesting Facts About Titan.

Life may exist on Titan, but it is likely very limited.

A molecule that forms the basis of DNA and RNA has been discovered in Titan's atmosphere.