NASA's Cassini spacecraft in orbit around Saturn recently spotted a surprising amount of methane in the geysers. The simple hydrocarbon compound was expected to exist on Enceladus, but to mostly stay trapped in the moon's underground ocean by the high pressure there.
The abundance of methane in Enceladus' plumes, however, means that the moon might actively produce more methane than had been thought. One explanation for the methane levels is that the compound forms through geological processes at the boundary where Enceladus' core meets the water. The same thing happens in Earth's hydrothermal vents—a hotspot for life. Another explanation is that methane locked in primordial ice gets released as the ice melts into the underground ocean. Either way, Enceladus keeps getting more interesting. And, just maybe, its deep water is home to our extraterrestrial cousins.