The origin of the geysers found around Saturn's moon Enceladus may have been the quick decay of radioactive elements with the shell of the moon billions of years ago, a new study has said.
Images beamed from NASA's Voyager spacecraft had clearly revealed some mysterious happenings in the snowy white moon. However a clearer picture only emerged when NASA's Cassini orbiter captured stunning images of geysers on Enceladus, which spouted water vapor and ice crystals.
These Cassini images captured in 2005, had posed a challenge to scientists to figure out the origin of the water vapor. Scientists had speculated that decay of radioactive isotopes or tidal heating was the force behind the geysers. Tidal heating is caused when the moon was squeezed and stretched by Saturn's gravity.
But researchers had admitted that these phenomena alone would not explain the powerful geysers. The new study model finds that the moon had a brief period of intense radioactivity causing its icy core to melt. Thereafter rocks fell into this mix forming a molten core.
"Enceladus is a very small body, and it's made almost entirely of ice and rock. The puzzle is how the moon developed a warm core," said lead researcher Dr. Julie Castillo. "The only way to achieve such high temperatures at Enceladus is through the very rapid decay of some radioactive species."
Scientists also said that the radioactivity period may explain how Enceladus is responsible for the chemicals found in the plume. These chemicals were measured by ion and neutral mass spectrometer on Cassini.
Dennis Matson of NASA's Jet Propulsion Laboratory (JPL) and a member of the study team said that the molecular nitrogen observed in the plumes could have come "from the breakdown of ammonia where the moon's core meets the water and ammonia above it. For this reaction to occur, the temperature needs to be at least 300 degrees Celsius. It eventually makes its way to the surface and it escapes to space where we observe it."
