Last year, scientists confirmed the enigmatic Saturnian moon Enceladus possesses a sub-surface ocean of liquid water. This groundbreaking discovery was made by NASA’s Cassini spacecraft currently in orbit around Saturn.
Today, mission scientists have further analyzed Cassini data from various Enceladus flybys to find that it’s not only a liquid water ocean; it could be salty too.
Cassini’s cosmic dust analyzer detected particles that were of relatively low salt content during distant passes over the Enceladean “tiger stripes” — a complex series of fissures cutting grooves through the moon’s icy crust, allowing prominent plumes of vapor and dust vent into space (pictured top). However, during closer flybys, the dust grains venting from the tiger stripes appear to have a very “ocean-like” composition, says NASA.
This indicates that most, if not all, the ice and water vapor ejected into space originate from a salty sub-surface liquid water ocean.
“There currently is no plausible way to produce a steady outflow of salt-rich grains from solid ice across all the tiger stripes other than salt water under Enceladus’s icy surface,” said Frank Postberg, a Cassini team scientist at the University of Heidelberg, Germany.
When salt water freezes, the salt content leaches out, leaving pure water ice behind. An example of this would be icebergs on Earth; the ice is pure frozen water, the salt is squeezed back into the ocean during the freezing process. If these particles originated from the surface ice on Enceladus, it wouldn’t contain salt. Therefore, these results indicate a liquid saltwater origin.
The particles detected in the Enceladus plumes over the tiger stripes are relatively large and rich in sodium and potassium.
It is thought there is a large reserve of liquid water approximately 80 km (50 miles) beneath the frozen surface of Enceladus. The water is theorized to be maintained in a liquid state through heating caused by tidal stresses exerted by Saturn and radioactive core processes.
The salt is thought to come from the liquid water sloshing around, dissolving salt compounds from the moon’s rocky interior. As the liquid ocean is under immense pressure, there is a huge pressure release as the tiger stripe fissures open, allowing the saltwater to rush to the surface and eject into space as salty water vapor.
This is the latest piece of evidence that Enceladus may play host to the most basic forms of life.
“This finding is a crucial new piece of evidence showing that environmental conditions favorable to the emergence of life can be sustained on icy bodies orbiting gas giant planets,” said Nicolas Altobelli, the European Space Agency’s project scientist for Cassini.
Enceladus has a salty, sub-surface liquid water ocean, organic compounds (hydrocarons) have been detected and a steady energy source keeps the whole system in cozy state. Although the moon isn’t exactly what we’d call home, to the basic lifeforms that emerged on our planet a couple of billion years ago, Enceladus may look like the perfect holiday destination.