Data gather by NASA's Cassini spacecraft suggests Saturn's icy Enceladus moon may contain sub-surface liquid water.
The data collected by Cassini's Ion and Neutral Mass Spectrometer during Enceladus flybys in July and Oct. 2008, were released in the July 23 issue of the journal Nature. "When Cassini flew through the plume erupting from Enceladus on October 8 of last year, our spectrometer was able to sniff out many complex chemicals, including organic ones, in the vapor and icy particles," said Hunter Waite, the Cassini Ion and Neutral Mass Spectrometer Lead Scientist from the Southwest Research Institute in San Antonio, Texas. "One of the chemicals definitively identified was ammonia."
On Earth, the presence of ammonia means the potential for sparkling clean floors and counter tops. In space, the presence of ammonia provides strong evidence for the existence of at least some liquid water.
How could ammonia equate to liquid water inside an ice-covered moon in one of the chillier neighborhoods of our solar system? As many a homeowner interested in keeping their abodes spick and span know, ammonia promptly dissolves in water. But what many people do not realize is that ammonia acts as antifreeze, keeping water liquid at lower temperatures than would otherwise be possible. With the presence of ammonia, water can exist in a liquid state to temperatures as low as 176 degrees Kelvin (-143 degrees Fahrenheit).
"Given that temperatures in excess of 180 Kelvin (-136 degrees Fahrenheit) have been measured near the fractures on Enceladus where the jets emanate, we think we have an excellent argument for a liquid water interior," said Waite.