If aliens exist in our solar system, Saturn’s icy moon Enceladus is considered one of the most likely worlds to harbor them.
Although the satellite’s surface is frigid, experts know there’s a lot of activity going on beneath the satellite, in part because of the discovery of hydrothermal vents in the vast, subsurface ocean that could provide the heat needed for life to thrive.
What they were less clear about, however, is how icy minerals and “vital nutrients” that could form the building blocks for life travel from the moon’s seafloor to Saturn as part of its “e” ring.
Now planetary scientists at the University of California Los Angeles (UCLA) believe they have solved the mystery of how this process works and how long it takes.
The experts said that as Saturn’s sixth-largest moon orbits the gas giant, the massive gravity of the latest tidal forces creates that flatten and compress Enceladus’ frozen core.
Aliens? If aliens exist in our solar system, Saturn’s icy moon Enceladus is considered one of the most likely worlds to harbor them
Discovery: Planetary scientists at the University of California Los Angeles have modeled how minerals from the moon’s seafloor rise to the surface, before being blasted into space by geysers
This deformation creates friction that heats the ocean floor, creating strong currents that can carry icy particles of silica from the seafloor to the surface through hydrothermal vents.
Here they are then blasted into space, along with massive amounts of water vapor and other organic compounds, by geysers in “tiger stripe” characteristics near the moon’s south pole.
WHY IS ENCELADUS SO EXCITING?
Enceladus is Saturn’s sixth-largest moon, measuring 313 miles (504 kilometers) across.
It’s an icy satellite with hydrothermal activity — a rare combination — with vents spewing water vapor and ice particles from a global ocean buried under the moon’s frozen crust.
A handful of worlds are thought to have oceans of liquid water beneath their frozen shells, but only Enceladus spews its ocean into space, where a spacecraft can sample it.
According to NASA observations, the plume contains organic compounds, volatile gases, carbon dioxide, carbon monoxide, salts and silica.
Microbes on our planet either produce these compounds or use them for growth, leading some to speculate that tiny organisms live in Enceladus’ hidden ocean.
This means that while Enceladus may look “inhospitable” like Saturn’s other moons, it is a prime candidate in our search for extraterrestrial life.
This material eventually forms one of Saturn’s famous rings.
“Our research shows that these currents are strong enough to pick up materials from the seafloor and carry them to the layer of ice that separates the ocean from the vacuum of space,” says UCLA PhD student Ashley Schoenfeld.
“The tiger stripe fractures that cut through the ice cover in this subsurface ocean could act as direct conduits for trapped materials to be flung into space. Enceladus gives us free examples of what is hidden deep below.”
Until now, scientists hadn’t understood the process by which this silica – one of the most abundant minerals in the Earth’s crust – was dragged into the geysers of the sixth largest of Saturn’s 83 known moons.
Previous studies had also disputed the length of time. One said months to years, while another said weeks to months, but the new study believes it’s somewhere in between and takes a matter of months.
The fact that heat emanates from Enceladus’s core keeps the water in the ocean from freezing, while also creating fissures in the seafloor through which heat escapes from the moon’s interior.
Evidence of these hydrothermal vents was discovered by NASA’s Cassini spacecraft during its visit to Saturn between 2004 and 2017.
Previous research has suggested that the heat from Enceladus’s interior should generate vertical convection currents in the ocean similar to those on Earth, so Schoenfeld and her colleagues went deeper.
The researchers analyzed Enceladus’ orbit, ocean and geologic features using data collected by Cassini and created a model using those currents to try and understand how silica was transported from the seafloor to the vacuum of space.
‘It’s like boiling a pan on a stove. Tidal friction adds heat to the ocean and causes upwelling currents of warm water,” Schoenfeld said.
Spectacle: This material eventually forms one of Saturn’s famous rings (pictured)
Process: Deformation of Enceladus’s frozen core causes friction that heats the ocean floor, creating strong currents that can carry icy particles of silica from the seafloor to the surface through hydrothermal vents (pictured)
“Our model provides further support for the idea that convective turbulence in the ocean efficiently transports vital nutrients from the seafloor to the ice sheet,” added study co-author Emily Hawkins, an assistant professor of physics at Loyola Marymount University.
The research is exciting because it offers more clues about how these hydrothermal vents work and what could be hiding in them or near them.
On Earth, they co-operate with life, even beyond the reach of sunlight.
These organisms feed on minerals released by the vents and rely on a chemosynthetic food web rather than the more common photosynthetic processes that use sunlight.
This is why scientists are so excited about the idea that Enceladus might harbor life, even though it is far from the sun and the ocean floor receives no sunlight at all.
Evidence of these hydrothermal vents was discovered by NASA’s Cassini spacecraft during its visit to Saturn between 2004 and 2017
Professor David Rothery from the Open University told MailOnline that microbes can feed on the chemical energy produced by reactions between water and hot stones.
He added: ‘Never mind that sunlight can’t penetrate to those depths — we also have similar “chemosynthetic life” clustered around hydrothermal vents on Earth’s sunless ocean floors.
“If there are microbes, more complex life forms may have evolved and eat the microbes.”
The UCLA researchers hope their findings can help guide future NASA missions that fly by, orbit, and even land on Enceladus.
These, in turn, could collect data that would allow scientists to further examine the moon’s hydrothermal vents to see if there are signs of life around them.
The research has been published in Communication Earth & Environment.
Where could aliens exist in our solar system? Mars, Jupiter’s moon Europa and Saturn’s satellites Enceladus and Titan are among the most likely worlds for extraterrestrial life, experts say
For thousands of years, humanity has struggled with the idea that we may not be alone in our solar system.
Speculation that aliens might exist date back to philosophers in ancient Greece, but it was in the mid-20th century when people’s imaginations really started to run wild — suddenly “little green men” were all over popular culture .
While the use of the phrase is believed to have originated in 1908, it was between the 1920s and 1950s that green Mars characters were plastered all over the covers of science fiction magazines and later on people’s TVs.
The reality is that if extraterrestrial life does exist in our solar system, it will be of a simpler kind, perhaps hidden in the clouds of Venus, beneath the surface of Mars, or in the vast subsurface oceans of one of Saturn’s icy moons.
But where else can you best find it? MailOnline speaks with a number of experts to find out.