Deep beneath its frozen bark, Enceladus’ dark waters may pass through.
According to a new study of the amount of ice covering the global oceans of the Saturnian moon, very similar streams to the Earth appear to be flowing there. If so, this means that Enceladus’s oceans may not be homogenous after all.
Enceladus will not give up his mysteries easily. Our first good look at it came in 1981, when Voyager 2 went through on its way to the Outdoor Solar System. Images of the probe showed a small ball of highly reflective ice, just 500 kilometers (310 miles) across, pushed by craters and separated by long fissures and mountain ranges, showing geological activity.
Then, in 2010, a big surprise: Saturn probe Cassini found geysers of melting water spraying from fractures in the frozen shell of Enceladus – evidence that the moon there was no ice all the way, but the harbor of a salt sea.
The combination of melting water and cracks in the ice helped scientists understand how Enceladus works. As Enceladus makes the 1.37-day elliptical orbit around Saturn, the variable gravitational forces pull and stretch at the moon. This pressure generates internal heating and georegulatory activity, and creates cracks in the surface ice.
The internal heating keeps the ocean fluid inside, and it sprays out through the cracks like geysers, which fall to the surface and come down. That internal heating would also generate direct convection currents – similar to those seen on Earth – sending warmer water up, where it would cool before circulating back down.
However, since Enceladus is so different from Earth, it is not clear whether its oceans are similar in other ways as well. Earth’s oceans are, on average, 3.7 kilometers (2.3 miles) deep. Enceladus’s is at least 30 kilometers deep, and covered by 20 kilometers of ice.
Of course we can’t see what’s going on in that ocean, but there are signs in the ice. We know that the poles have thinner ice than the equator, and much more at the south pole, where the moonexploding geysers. This, according to a team of researchers led by Caltech-based geologist Ana Lobo, reveals that something more complex than just convection is just going on in the ocean below.
Thinner ice – perhaps unsurprisingly – seems to be associated with greater melting, and thicker ice with more frost. This means that where the ice is thicker, the ocean is saltier, as only the water freezes, and most of the salt is released back into the water. . This makes the water under the ice mound, so it sinks to the bottom of the ocean.
In smelting regions, the opposite occurs. The water is fresher and denser, so it stays on top. Here on Earth, this leads to a kind of conventional “conveyor belt”. Water freezes at the poles, and the thicker, saltier water sinks to the bottom and flows in a stream towards the equator, while waters are warmer. from the equator flows to the poles where they are frozen, and as a result denser cold saline water sinks, and so on.
The team developed a computer model of Enceladus, based in part on our understanding of these conveyor belt currents, and the team found that a current similar to the observed thicknesses could be represented in the moonAnd ice.
Now, it is not clear whether Enceladus has life. It is very far from the Sun, but, due to the geothermal interior heating, chemosynthetic food figs may be similar to those found around hydrothermal traces in the Earth’s dark, dark oceans. If life hides deep in the oceans of Enceladus, the team’s decisions may help us figure out where to find it.
We know that the waters of Enceladus are salty; the water surveyed by Cassini from the geysers appeared so abundant. If the team is right, the salt levels in these geysers may be on the lower side, as they are evacuated from the melting area, and the surrounding waters may be submerged. ‘belt much saltier.
We also know that ocean currents on Earth play a role in nutrient circulation. A deeper knowledge of salinity levels and nutrient circulation would help to clarify the areas of Enceladus that are likely to survive as we know it.
At the time of writing, there are no specific messages to Enceladus in the pipes. However, Dragonfly’s mission to Saturn’s Titan Titan, the Europa Clipper could be sent to explore Jupiter’s frozen moon and (possibly) Europa’s geyser-spouting, and the JUpiter ICy moons Explorer (JUICE) all shed more light on round an ocean of these strange oceans. , world gelid.
The team ‘s research was published in Geology of nature.