NASA Scientists Introduce New Discovery About Enceladus' Geysers And Its Implications

NASA scientists have made a new discovery about the geysers erupting from the icy shell of Saturn's moon Enceladus. Their research suggests that the geysers, which blast water vapor and ice particles into space, are outbursts of trapped subsurface gas that burst through cracks in the ice shell. According to the scientists, these outbursts could suggest that Enceladus' ocean – believed to be a potential haven for life – is larger than previously thought.

The research was published in the journal Nature Astronomy on April 18, 2023. It focuses on understanding the mechanism behind the geysers on Enceladus, which are the only direct indication of a body of liquid water below the surface of Saturn's satellites.

"This research provides insights into the internal structure and evolution of Enceladus," said in a statement Phil Valet, associate director of NASA's Astrophysics Division. "The findings also have implications for other moons of Jupiter and Saturn, as well as exoplanets with water vapor plumes."

The eruption of the geysers on Enceladus was first observed by the Cassini spacecraft in 2005. Since then, scientists have analyzed the phenomenon to determine what kinds of molecules are being ejected from the moon's south pole.

According to the statement, the scientists employed data collected by Cassini as well as theoretical models to conclude that the geysers hole up a large, salty ocean beneath the moon's surface. Saltwater is known to inhibit the freezing point of water, meaning the ocean beneath Enceladus' ice shell could be deeper and larger than predicted.

"We have figured out that Enceladus' ocean is larger than previous estimates suggested," said co-author Peter Wurzfeld, a research scientist at NASA's Jet Propulsion Laboratory (JPL) in Southern California. "And we've found the driving mechanism for the ocean's possibility to maintain its supply of heat and nutrients."

The scientists also suggest that the geysers could be used to determine the geographical layout of the ocean below. Given that the salty ocean is thought to be a potential harbor for life, the geysers could present a unique opportunity to gather insights about the ocean without having to drill through the ice shell.

"The fact that Enceladus' geysers are closely associated with the heating of its ocean is a huge step forward in our understanding of the moon," said co-author Amanda Hendrix, a professor of planetary science at the University of Arizona. "We are now closer to understanding how the ocean releases its heat and how intact the ocean may be."

The research concludes that the geysers are the result of trapped subsurface gases – likely a combination of water vapor and methane – bursting through cracks in the ice shell. While the methane is thought to be produced by various mechanisms, one intriguing possibility is that the molecule is naturally produced by microbes present in the ocean. If this is the case, it could provide a valuable opportunity to gather insights about the metabolic products of such potential life forms.

"The next step is to determine whether there's a correlation between where the geysers are and where the ocean is," said lead author Carolyn Porch, a doctoral student at the University of British Columbia. "If the geysers are showing us the way, it may be that much easier to determine the depth and size of the ocean."

Understanding the nature of the geysers could also provide insights into the potential habitability of other moons and exoplanets. Moons such as Jupiter's Europa or Saturn's Ganymede may also have hidden oceans beneath their icy shells. Furthermore, planets outside of our solar system with water vapor plumes, as indicated by NASA's Transiting Exoplanet Survey Satellite, could be worth investigating to determine whether they are suitable for life.

"The geysers on Enceladus are a gift," said co-author Lisa Graziano, a research physical scientist at JPL. "They offer us an easy way to sample the ocean without having to drill through the ice."