(ORDO NEWS) — Mysterious silica ejected in massive quantities by Saturn’s icy moon Enceladus is new strong evidence of heat sources at the bottom of the global ocean.
According to a new analytical model, the internal heating of the moon’s core creates ocean currents that carry silica particles that are ejected from deep-sea hydrothermal vents, which also release heat into the surrounding waters.
It’s a tantalizing find that hints at the real possibility of life deep beneath an alien ocean on an alien world.
When the Cassini probe spent years in orbit studying Saturn, it made an amazing discovery.
The planet’s E ring – the second outer ring in a vast system of rings – has a composition rich in microscopic grains of silica, as well as ice made from water, ammonia and carbon dioxide.
We also found silica particles. emanating from Enceladus in the form of ice plumes that break out of cracks in the thick ice shell of the Moon; Scientists have determined that the composition of the E ring comes from Enceladus from its rocky core. And the chemical composition and grain size suggest high temperatures.
But how silica gets from the core of Enceladus into the depths of the oceans, to be ejected through the ice in the form of plumes, was something of a mystery. mystery.
Enceladus is a real miracle. The moon is covered in a thick shell of ice that averages 18 to 22 kilometers (11 to 14 miles) thick.
But its orbit around Saturn is not perfectly circular, but elliptical, meaning its distance from the planet varies, as does the strength of gravity between the two.
This variable gravity stretches and compresses Enceladus, heating up its core.
Therefore, under the ice shell there is a global liquid ocean with a depth of more than 10 kilometers, and the heat emanating from the core does not allow the water to freeze.
It also raises the possibility of hydrothermal vents, cracks in the seafloor through which heat escapes from the Moon’s interior.
Previous research has suggested that heat from the interior of Enceladus should create vertical convection currents in the ocean similar to those seen on Earth.
Now, a team of planetary scientists led by Ashley Schoenfeld at UCLA has created a model that includes these flows to try to understand the transport of silica on Enceladus.
“It’s like boiling a pot on. Tidal friction heats up the ocean and causes updrafts of warm water,” Schoenfeld explains.
“Our study shows that these currents are strong enough to lift materials from the sea floor and bring them into the icy shell that separates the ocean from the vacuum of space.
The tiger stripe faults that cut through the icy shell in this 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 below.”
The implications are pretty exciting. Previous studies have shown that the silica and other materials found by Cassini in Enceladus’ plumes are consistent with those found in and near hydrothermal vents.
Here on Earth, hydrothermal vents are teeming with life. even far beyond the reach of sunlight.
Entire ecosystems thrive on the chemosynthetic food web, using the chemical reactions of elements interacting at high temperatures to produce energy, rather than the more common photosynthesis processes that rely on sunlight.
This has led astrobiologists to speculate that the icy moons of Enceladus, for example, could harbor life even though they are far from the Sun, and the ocean floor receives no life-giving sunlight at all.
The new study adds to a growing body of evidence that suggests there are hydrothermal vents on Enceladus, and if there is life, we could detect it without trying to break through the ice. An orbiter or lander, several of which are currently under consideration, could find biomolecules right on the moon’s icy surface.
“Our model,” says planetary scientist Emily Hawkins of Loyola Marymount University, “further supports the idea that convective turbulence in the ocean efficiently transports vital nutrients from the sea floor to the icy shell.”
Isn’t this an intriguing idea? We may have to change its name to Enticingeladus.
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