Vital Ingredient for Life Found on Enceladus
A vital building block of life, Phosphorus, is used to construct DNA and RNA. Now, an analysis of data from NASA’s Cassini spacecraft reveals that Enceladus' undergorund ocean contains the crucial nutrient. Not only that, its concentrations there may be thousands of times greater than in Earth’s ocean, planetary scientist Yasuhito Sekine reported December 14 at the American Geophysical Union’s fall meeting.
Sekine of the Tokyo Institute of Technology said: "the essential element may abound on many other icy worlds too, holding promise for the search for alien life". Enceladus is a world encased in ice, with an ocean of salty water tucked beneath its cold surface. Planets icy shell is filled with geysers blasting vapor and ice grains. It was in that space - faring spray that the scientists have detected organic molecules, which is the main reason why many researchers consider Enceladus to be among the most likely places to house extraterrestrial life.
Morgan Cable, an astrobiologist at the Jet Propulsion Laboratory in Pasadena, California had this to say: “We knew that Enceladus had most of the elements that are essential for life as we know it — carbon, hydrogen, nitrogen, oxygen and sulfur. Now that phosphorus has been confirmed, Enceladus now appears to meet all of the criteria for a habitable ocean.”
But until recently, researchers weren’t sure if phosphorus even existed on Enceladus. On Earth’s surface, phosphorus is not easy to find, the element is rather scarce. Much of the phosphorus is locked away in minerals, and its availability often controls the pace at which life can proliferate. So Sekine and colleagues analyzed chemical data, collected by the now-defunct Cassini, of particles in Saturn’s E ring, a halo of material ejected from Enceladus’ jets that wraps around Saturn.
The researchers have found that some ice grains in the E ring are enriched in a phosphorus compound called sodium phosphate. It is estimated that a kilogram of water from Enceladus’ ocean contains roughly 1 to 20 millimoles of phosphate, a concentration thousands of times greater than in Earth’s big blue ocean. Furthermore, Sekine explains: "at the floor of Enceladus’ subsurface ocean, phosphate may arise from reactions between seawater and a phosphate-bearing mineral called apatite, before being ejected through geysers into space. Apatite is often found in carbonaceous chondrites, a primitive, planet-building material. Many other icy ocean worlds may contain apatite as well, Sekine said. Similarly, they too could also carry high levels of phosphate in their oceans. That richness could be a boon for any potential alien organisms".