A novel theory proposed by planetary scientists from Caltech and NASA’s Jet Propulsion Laboratory challenges the current idea that the ocean of salt water of Enceladus, Saturn’s sixth largest moon, is one -gender.
Enceladus tiger strips are known to splash ice from the frozen side of the moon into space, creating a cloud of delicate ice grains over the moon’s south pole and creating Saturn’s mysterious E-ring. Evidence for this has come from NASA’s Cassini spacecraft that altered Saturn from 2004 to 2017. This image shows a high-resolution image of Enceladus from a close-up flyby. Tiger stripes are shown in a false blue color. Image credit: NASA / ESA / JPL / SSI / Cassini Image Team.
In 2014, NASA’s Cassini spacecraft found evidence of an underground ocean on Enceladus and sampled water from geyser-like explosions that occur through cracks in the ice at the south pole.
This is one of the few places in the Solar System with melt water, making it a target of interest for astrobiologists looking for signs of life.
The ocean on Enceladus is almost completely unlike Earth.
The Earth’s ocean is relatively shallow, covering three-quarters of the planet’s surface, warmer at the summit from the sun’s rays and colder in the depths near the seabed, and contains windswept currents. prevailing.
Enceladus, meanwhile, appears to be a spherical and completely subterranean ocean at least 30 km deep and cooled at the summit near the ice shell. and warmed at the base by heat from the heart of the moon.
Despite their differences, Caltech graduate student Ana Lobo and colleagues suggest that Enceladus’ ocean currents are similar to those on Earth.
The oceans of Enceladus and the Earth have one important feature: they are salty. And as can be seen by the team, changes in salinity could be drivers of ocean circulation on Enceladus, just as they are in the South Earth Ocean.
This artist ‘s design shows a weak view of the interior of Enceladus. A plug of ice grains, water vapor and organic molecules erupts from fractures in the lunar south pole region. Image credit: NASA / JPL-Caltech.
“Cassini gravity measurements and heat calculations have already shown that the ice shell is thinner at the poles than at the equator,” said Dr Andrew Thomson, a researcher at the Department of Geological and Planning Sciences at Caltech.
“The poles are likely to have sections of thin ice associated with melting and sections of thick ice at the equator by freezing. ”
This affects ocean currents because when salt water freezes, it releases the salts and makes the surrounding water heavier, causing it to sink. The opposite occurs in regions of melting.
“Experiencing ice circulation allows us to place restrictions on circulation patterns,” says Lobo.
The team’s computer model suggests that the regions of freezing and thawing, characterized by the structure of the ice, would be connected by the ocean currents.
This would create a pole-to-equator circulation that will affect the circulation of heat and nutrients.
“By understanding which parts of the subterranean ocean can be so hospitable to life as we know it could one day inform efforts to find signs of life,” said Dr. Thomson.
The study was published in the journal Geology of nature.
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AH Lobo et al. Pole-to-equatorial crossing of Enceladus. Nat. Geosci, published online March 25, 2021; doi: 10.1038 / s41561-021-00706-3