Saturn’s moon Enceladus has an even better chance of supporting extraterrestrial life than previously thought: Researchers have discovered its oceans are more complex than first believed.
The moon’s oceans shoot plumes of carbon dioxide into space, researchers have found, using data from NASA’s Cassini spacecraft. The findings, published in Geophysical Research Letters, point to reactions between the water and the core of the celestial satellite as the source of the complexity, discovered thanks to a new technique the researchers used.
“By understanding the composition of the plume, we can learn about what the ocean is like, how it got to be this way and whether it provides environments where life as we know it could survive,” said Southwest Research Institute (SwRI) researcher Christopher Glein in a statement. “We came up with a new technique for analyzing the plume composition to estimate the concentration of dissolved CO2 in the ocean. This enabled modeling to probe deeper interior processes.”
The Cassini spacecraft intentionally plunged itself into Saturn’s atmosphere in September 2017 after it was launched in 1997 at a total cost of $3.9 billion ($2.5 billion in pre-launch costs and $1.4 billion in post-launch). It spent 13 years circling, studying and taking data of Saturn and its moons.
Combined with previous discoveries of molecular hydrogen and silica, the “abundance” of carbon dioxide reacting with the core of the moon and the water in the moon’s subsurface oceans add credence to the idea there are energy sources on Enceladus that could support life.
“The dynamic interface of a complex core and seawater could potentially create energy sources that might support life,” said SwRI’s Hunter Waite in the statement. “While we have not found evidence of the presence of microbial life in the ocean of Enceladus, the growing evidence for chemical disequilibrium offers a tantalizing hint that habitable conditions could exist beneath the moon’s icy crust.”
“The implications for possible life enabled by a heterogeneous core structure are intriguing,” Glein added. “This model could explain how planetary differentiation and alteration processes create chemical (energy) gradients needed by subsurface life.”
Prior to the flybys by Voyager 1 and Voyager 2 in the early 1980s, not much was known about the “ocean-world” moon, despite it being discovered in 1789.
In 2017, NASA found the presence of hydrogen in its atmosphere, something Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory, said at the time could be meaningful as a “potential source for energy from any microbes.”
One year later, scientists made a startling announcement when they said they had found complex organic molecules, the “building blocks” for life, on the moon. Separately that year, researchers determined Enceladus’ ocean is likely 1 billion years old, placing it in the sweet spot for supporting life.
Enceladus is not the only celestial satellite of Saturn to intrigue scientists. In June, NASA announced the latest mission in its New Frontiers program. Known as Dragonfly, the mission will explore Saturn’s largest moon, Titan, which could potentially host extraterrestrial life.