On Titan, the largest of Saturn's 62 known moons, there are numerous lakes and oceans. Although it is less extensive than Earth, it bears similarities to our planet due to the existence of liquids, wind and rain, which have created landscapes that are familiar to us.
Under its thick, hazy atmosphere of nitrogen and methane, astronomers have discovered mountains, dunes, and lakes. Instead of water, liquid methane and ethane flow through riverbed-like channels into seas the size of North America's Great Lakes.
But there are also methane lakes on Earth. In cold areas of our planet there are lakes whose water stores large amounts of this gas in the form of thousands of frozen bubbles that look like pearls.
The highly flammable compound comes from methanogenic bacteria that inhabit these environments. They expel it by breaking down the organic matter they take from the bottom to obtain nutrients, in a process called methanogenesis , the same one used by organisms that live in the digestive tract of ruminants.
They are extremophilic microorganisms of the group of archaebacteria, capable of withstanding extreme cold, dark and oxygen deprived conditions. The difference in density forces the gas blisters to rise to the surface, but since the lake is frozen, they are trapped along the way. In spring, the bubbles rise and are finally expelled into the atmosphere.
