They say the unmanned Cassini dove through geysers erupting from the surface of one of the planet's moons this month and found organic matter, one of many ingredients that make an environment hospitable to extraterrestrial life.
The scientists say it's a marker for further research into whether the icy satellite Enceladus has such an environment.
The principal investigator for one of Cassini's instruments says that while the jet plumes were mostly water vapor, the probe found traces of methane and simple organic compounds.
Scientists generally agree the presence of water, organic compounds and a stable heat source are needed to support primitive life.
