Waves have been detected on Titan's surface

Researchers believe they have detected the first liquid waves on the surface of another world. Cameras have shown isolated ripples in a sea called "Pugna Mare" on the surface of Saturn's moon, Titan.

However these seas aren't filled with water but with various hydrocarbons like methane and ethane. On Titan they exist in their liquid state, where the surface temperature averages about -180C

Scientists view Titan as kind of like a looking-glass version of Earth with a substantial atmosphere and a seasonal cycle. Wind and rain shape the surface to form river channels, seas, dunes and shorelines. You could say that it's like our moon combined with some features from Earth.

The vast majority of Titan's lakes and seas are concentrated around the north polar region. Just one of these bodies of liquid - Ligeia Mare - is estimated to contain about 9,000 cubic km of mostly liquid methane, equating to about 40 times the proven reserves of oil and gas on Earth.

• It is the only moon in the Solar System with clouds and a substantial atmosphere
• Titan is Saturn's largest moon and the second biggest in the Solar System
• Wind and rain create similar features to those found on Earth, such as dunes, lakes and rivers
• But on Titan it rains liquid methane, filling the rivers, lakes and seas with hydrocarbons (molecules made up of just hydrogen and oxygen)