Titan is the only other body in the solar system other than Earth with liquid on its surface (artist’s impression) (Picture: Getty/Stocktrek Images)
A decade after discovering mysterious floating ‘magic islands’ on Saturn’s moon Titan, we may finally know exactly what they are.
Saturn’s main moon is the only one in the solar system that has a significant atmosphere, and is the only place other than Earth that has liquid on its surface – in the form of seas, lakes and rivers.
However, they are not filled with water, but liquids like ethane and methane.
In 2014, Nasa’s Cassini spacecraft first spotted the islands as bright, transient dots, which baffled scientists by how they could move and disappear.
Now, a new study may have solved the mystery of how they appear and what they are.
Dr Xinting Yu, an assistant professor at the University of Texas San Antonio, said these magic islands could be floating chunks of glacier-like snow shaped like a honeycomb or Swiss cheese.
She believes they are formed by organic solid that fall as snow through the haze of Titan’s orange sky.
Saturn’s moon Titan (Picture: Nasa/ Getty)
‘I wanted to investigate whether the magic islands could actually be organics floating on the surface, like pumice that can float on water here on Earth before finally sinking,’ said Dr Yu.
‘For us to see the magic islands, they can’t just float for a second and then sink. They have to float for some time, but not for forever either.’
For the past 10 years, scientists have come up with a range of theories to rationalise the magic islands, saying they are either phantom islands or real.
It was suggested that the islands could be caused by waves in the Titan’s methane or ethane lakes.
By Dr Yu and her team found that in the upper atmosphere of the moon, molecules could clump together, and freeze to produce snow that lands on the surface.
The mystery islands could sink, rather than dissolving (Picture: Nasa/JPL)
The team also wanted to discover whether, if the ‘snow’ was to land on the surface, would it dissolve? They found that since the liquid bodies are already packed with organic molecules, this dissolution couldn’t happen.
Individual snow clumps would be too small to form ‘islands’ on their own, but if they clumped together, then the larger pieces could break off and float on the methane lakes.
The process is similar to how sheets of ice break away from glaciers on Earth and float into the seas – also known as ‘calving.’
And because the islands are full of holes, like Swiss cheese, instead of dissolving, the islands slowly sink as the liquid ethane or methane filters through its network of holes.
Wild.