Saturn’s moon Enceladus has buried ‘churning’ ocean currents beneath its 12 ice miles, according to new study.
Enceladus – one of Saturn’s 82 moons – is already known to hide water beneath its shiny, frozen surface.
But experts at the California Institute of Technology (Caltech) believe that ocean currents flowing on Enceladus are somewhat similar to those near Antarctica, driven by salt water.
They based their estimates on computer modeling using data collected by the Cassini spacecraft that was no longer working at NASA.
Enceladus is one of the few places in the Solar System with meltwater, along with the Earth and moon Jupiter Europa, making it a target of interest for astrobiologists.
The new research could tell scientists where to find one day signs of life on Enceladus at future satellite missions, according to Caltech.
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Enceladus (pictured in an image from NASA’s Cassini satellite) is the sixth largest of Saturn’s branches, with a diameter of about 310 miles. The moon is covered in a moving layer of pure ice, making it one of the most reflective bodies in the Solar System.
ENCELADUS: QUICK QUESTION
Found: 28 Aug 1789
sort of: Ice moon
Diameter: 313 miles (504km)
Orbital time: 32.9 hours
All day: 32.9 hours
Mass: About 680 times smaller than Earth’s moon
‘Understanding which regions of the underground ocean could be so hospitable to life because we know it could one day inform efforts to find signs of life,’ said study author Andrew Thompson, professor of environmental science and engineering at Caltech.
Enceladus – Saturn’s sixth largest moon out of a total of 82 – is a frozen area of just 313 miles in diameter (about one-seventh the diameter of Earth’s moon).
Enceladus is covered in a mobile layer of pure ice, making it one of the most reflective bodies in the Solar System.
Despite its small size, Enceladus caught the attention of scientists in 2014 thanks to data from Cassini.
At the time, the plucky spacecraft found evidence of its subterranean ocean and sampled water from geyser-like explosions that occur through cracks in the ice at the south pole.
Jets of water and some hard grains like ice crystal spouts from roots in the frozen surface called ‘tiger stripes’.
Despite the Earth’s harbor water and Enceladus, the ocean on Enceladus is almost completely unlike Earth’s water.
The Earth’s ocean is relatively thin, averaging 2.2 miles (3.6 km), and covers three-quarters of the planet’s surface.
Our ocean is also warmer at the top thanks to the sun’s rays and colder in the depths near the seabed, and there are wind-swept currents.
Enceladus appears to have an underground ocean, at least 18.6 miles (30 km) deep, that will run the length of the moon.
An interior photograph of Saturn’s moon Enceladus showing an ocean of melting water glistening between its rocky heart and frozen crust. The layers shown here are not thick to scale
The ocean of Enceladus is cooled at the top near the ice shell and warmed at the bottom by heat from the heart of the moon.
Despite their differences, the oceans of Enceladus and Earth have one important feature – they are salty.
Changes in salinity could be drivers of ocean circulation on Enceladus, just as they are in the South Earth Ocean, which surrounds Antarctica.
Gravity measurements and heat calculations from Cassini had already revealed that the Enceladus ice shell is thinner at the poles than at the equator.
Unsurprisingly, the poles appear to have regions of thin ice associated with melting, while the equator has sections of thick ice associated with freezing, Thompson said.
But this affects the 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 thin ice at the poles associated with melting.
Cassini is pictured here in a NASA photo. Cassini was launched from Cape Canaveral, Florida in October 1997
A computer model, based on Thompson’s studies on Antarctica, suggests that the regions of freezing and thawing, identified by the ice structure, would be connected by ocean currents.
This would create a pole-to-equator belt, almost like a conveyor belt, which affects the circulation of heat and nutrients.
The theory challenges conventional thinking that the ocean ocean of Enceladus is homogeneous with the exception of some direct mixture guided by the warmth of its heart.
‘Experiencing ice circulation allows us to place restrictions on circulation patterns,’ said Ana Lobo, a Caltech graduate student.
A very appropriate computer model, based on Thompson’s studies on Antarctica, suggests that the regions of freezing and thawing, identified by the ice structure, would be connected by ocean currents.
‘This would create a pole-to-equator circulation that will affect the circulation of heat and nutrients.’
Scientists are still benefiting from the rich data obtained by the robotic spacecraft Cassini, which was operational for nearly 20 years after its launch in October 1997.
Cassini’s mission ended in September 2017 when it was deliberately moved into Saturn’s high atmosphere before running out of fuel.
In 2019, Cassini data revealed that Saturn’s largest moon lake, Titan, is full of methane and 300 feet deep.
Another 20 new moons were confirmed orbiting the planet in 2019, leaving it as the ‘king of the moon’ of the solar system, defeating 79 at Jupiter.
The new study was published in Nature Geoscience.
WHAT DOES IT HAVE TO DO WITH MY 20-YEARS TO SATURDAY?
Cassini was launched from Cape Canaveral, Florida in 1997, then spent seven years in orbit and then 13 years in orbit Saturn.
An artist’s impression of the Cassini spacecraft studying Saturn
In 2000 he spent six months studying Jupiter before reaching Saturn in 2004.
In that time, he discovered six more branches around Saturn, three-dimensional structures rising above Saturn’s rings, and a major storm that swept across the planet for nearly a year.
On December 13, 2004 he made his first flyby of Saturn Titan and Dione branches.
On December 24 they released the Huygens probe built by the European Space Agency on Saturn’s Titan Titan to study the atmosphere and surface.
There he discovered eerie hydrocarbon lakes made of ethane and methane.
In 2008, Cassini completed its main mission to study the Saturn system and began its mission expansion (Mission Cassini Equinox).
In 2010 he embarked on his second mission (the Cassini Solstice Mission) which lasted until it exploded into the atmosphere of Saturn.
In December 2011, Cassini received the highest resolution images of Saturn Enceladus’ moon.
In December of the following year they discovered the motion of Venus to test the ability to observe planets outside our solar system.
In March 2013 Cassini made the last flyby of Saturn’s moon Rhea and measured its internal structure and attraction.
Cassini not only studied Saturn – he also got amazing views of its many moons. In the image above, Saturn’s moon Enceladus can be seen moving before the rings and Pandora’s little moon. It was captured on November 1, 2009, with the entire view surrounded by the Sun.
In July of that year Cassini captured Saturn with a black light to closely examine the rings and also captured an image of the Earth.
In April this year they completed the flyby closest to Titan and began the Grande Finale orbit which ended on September 15th.
‘The mission has changed the way we think about where life might have developed outside of our Earth,’ said Andrew Coates, head of the Planning Science Group at the Mullard Space Science Laboratory at University College London.
‘Apart from Mars, extraterrestrial branches such as Enceladus, Europa and even Titan are now major conquests for life elsewhere,’ he said. ‘We have completely rewritten the textbooks about Saturn.’