Lakes of Titan

The lakes of Titan, Saturn's largest moon, are bodies of liquid ethane, methane, and propane that have been detected by the Cassini–Huygens space probe, and had been suspected long before. The large ones are known as maria (seas) and the small ones as lacūs (lakes).

History

The possibility that there were seas on Titan was first suggested based on Voyager 1 and 2 data. The data showed Titan to have a thick atmosphere of approximately the correct temperature and composition to support them. Direct evidence was not obtained until 1995 when data from the Hubble Space Telescope and other observations had already suggested the existence of liquid methane on Titan, either in disconnected pockets or on the scale of satellite-wide oceans, similar to water on Earth.

The Cassini mission affirmed the former hypothesis, although not immediately. When the probe arrived in the Saturnian system in 2004, it was hoped that hydrocarbon lakes or oceans might be detectable by reflected sunlight from the surface of any liquid bodies, but no specular reflections were initially observed.