(ORDO NEWS) — One of the unique features of Enceladus is the geysers of water vapor erupting from under the snow-white ice surface in its southern region.
A team of American researchers have developed a detailed analytical model of the satellite’s subsurface currents to finally explain the presence of silicon nanoparticles in water ejecta that form the basis of one of Saturn’s outer rings.
Enceladus is the sixth largest of the 83 moons of Saturn and one of the most mysterious and interesting bodies to study in the solar system.
Its entire surface is covered with a multi-kilometer layer of ice, which is why it reflects more than 80% of the radiation falling on it.
Beneath the surface of the satellite is a global ocean of salty liquid water bursting through cracks in the ice crust of the south polar region in the form of powerful geysers.
The Cassini spacecraft , which studied Saturn and its moons from 2004 to 2017, conducted a chemical analysis of the south polar plumes that form the basis of the outer E ring of the sixth planet from the Sun.
In addition to water vapor, nitrogen, carbon dioxide and methane, nanometer-sized particles of silicon dioxide (silica) were found in the emissions of Enceladus.
The presence of these nanoparticles meant that the water, before it was thrown out from under the surface of the satellite, was in contact with the silicate rock and was exposed to high temperatures.
And if in general terms the process of the appearance of silica in the emissions of Enceladus is clear, then what specific mechanisms are behind the formation of such geysers was not completely clear.
In a new paper, a group of American researchers, led by scientists from the University of California, has developed an analytical model that describes how thermal convective flows are formed due to tidal deformation in the silicate core of Enceladus, leading to observed ejections.
It has long been known that Enceladus’ active geology is fueled by tidal forces generated as it orbits Saturn.
The gravity of the gas giant stretches and compresses the satellite, deforming and creating friction in both the icy shell and the porous silicate core.
Because of these processes, the surface of Enceladus is covered with cracks, and the core, as shown by a new study, heats up enough to form hot and narrow turbulent upwelling zones.
These zones, represented in the model as the so-called Taylor convection columns, are cylindrical in shape and lift deep ocean waters along with silica particles to the surface, where they are then ejected into space.
“Our study shows that these currents are strong enough to pick up materials from the bottom and deliver them to the icy shell that separates the ocean from the vacuum of space.
Cracks, known as tiger stripes, that cut through the entire thickness of the ice shell all the way to the subsurface ocean, could serve as direct conduits for trapped materials to be ejected into space.
Enceladus is giving us free samples of what lies deep within its interior,” said study lead author Ashley Schoenfeld, a PhD student in planetary science at the University of California.
In addition to silica nanoparticles, Cassini detected a significant amount of hydrogen gas in the plumes generated by Enceladus.
Together, these two facts provide strong evidence for hydrothermal activity on the ocean floor.
On Earth, in similar deep-sea hydrothermal vents, many living organisms find refuge for themselves, which feed on the minerals released there.
Future space missions will need to collect more data on the hydrothermal activity of Enceladus, allowing scientists to further study the physical and chemical properties of the core-ocean system and answer the question of the existence of any life there.
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