We already know that Saturn’s moon Enceladus could be hiding some pretty interesting characteristics below its apparently dead, frozen exterior namely a subsurface ocean that might be warm enough to support life.
New findings reveal more details about the composition of that sea and that its waters are erupting into space in broad, “tiger stripe” sheets rather than narrow jets as it previously appeared.
Two separate teams published papers in academic journals this week about the water observed at Enceladus, both using data from the Cassini spacecraft that has been wandering around spying on Saturn and its moons for a few years now.
The researchers of the first paper, from the journal Geochimica et Cosmochimica Acta, used mass spectrometry data of ice grains and gases in one of the plumes shooting out of the satellite.
Spectrometry is a fancy and fascinating way of looking at the elements of light the human eye can’t detect to determine the composition of a sample.
Looking at this data, the team was able to determine the content of the plumes — and by extension the subsurface ocean — to be highly salty with an alkaline pH of around 11 or 12.
The salt is the same familiar sodium chloride found in our oceans and on our french fries here on Earth, but there’s also a healthy dose of sodium carbonate, also known as “soda ash,” which we use here in detergents as a water softener and sometimes in cooking.
This makes Enceladus’ ocean more similar to one of the “soda lakes” here on Earth, like California’s Mono Lake. You may know that Mono Lake isn’t renowned for its fishing, but that doesn’t mean this kind of water can’t support life. In fact, there are certain types of fish that can thrive in soda lakes, and sea monkeys love it, too.
The high pH in the water on Enceladus could be caused by a process called serpentinization that is a result of the ocean interacting with the rocky core on its sea floor, and a pretty big deal when considering the moon’s potential as a distant-future scuba-diving destination.
“Why is serpentinization of such great interest? Because the reaction between the metallic rocks and the ocean water also produces molecular hydrogen (H2), which provides a source of chemical energy that is essential for supporting a deep biosphere in the absence of sunlight inside moons and planets,” lead author Christopher Glein, of the Carnegie Institution for Science, said in a release. “The discovery of serpentinization makes Enceladus an even more promising candidate for a separate genesis of life.”
A second scientific publication this week finds that the pressure of that surprising subsurface soda sea on Enceladus is creating another stunning phenomenon — namely that salty soda water is not emerging from the moon in the form of pinpoint discrete jets as previously thought, but actually as broad, curtainlike eruptions along “tiger stripe” fractures in the surface.
“Some prominent jets likely are what they appear to be, but most of the activity seen in the images can be explained without discrete jets,” said Joseph Spitale, lead author of the study published in the journal Nature, in a statement from NASA.
Basically, that explanation is that you have water, ice and gases erupting along these long cracks in the surface — something we sometimes see with lava in Hawaii and Iceland. (For pictures of my recent trip to Iceland’s “Game of Thrones” scenery, see here.) Along much of the length of these cracks, the eruptions weren’t big enough for Cassini to see, except in places where the “tiger stripes” folded over on themselves — like the folds in a curtain. Those folds could also explain the discrete jets Cassini observed earlier.