Saturn's moon Enceladus has key ingredient for life

• "Phosphorus, the least abundant of the bio-essential elements, has not yet been detected in an ocean beyond Earth," the researchers write this week in the journal Nature.
• Phosphate, an ion of phosphorus, forms the backbone of DNA and helps organisms make the energy-carrying molecule adenosine triphosphate (ATP).

Details: Enceladus has an ocean beneath its ice-covered surface that ejects water from geysers that then supply icy bits to an outer ring of Saturn.

• Earlier analysis of those salt-rich ice grains by the Cassini spacecraft indicated Enceladus' ocean contained sodium, potassium, chlorine and other organic compounds.
• In the new study, researchers used data collected from Cassini's Cosmic Dust Analyzer. They found sodium phosphate molecules in 9 of 345 ice grains Cassini analyzed as it passed through Saturn's outer E ring.
• In laboratory studies, the team then demonstrated phosphate could exist on Enceladus in much higher concentrations — several hundredfold — than on Earth and possibly in the icy oceans of other planets where alkaline water can interact with rocks.