Saturn's Moon Enceladus Shows Signs of Ongoing Geyser Activity, Could Hold Microbial Life
Previous studies have already shown that Saturn's moon Enceladus is host to over 100 geysers, making it a plausible candidate for microbial life. Now, a new study shows evidence that Enceladus not only has geysers, but ongoing geyser activity to this day.
The evidence comes from Cassini data taken a decade ago, specifically tiny grains of rock that were found on the moon's surface. The research team found that the grains were mostly made of silica, a mineral found on Earth that is the result of rock interacting with water. Since the grains were remarkably uniform in size, they were alerted to the fact that some sort of unusual process formed these rocks, and were able to work backwards to determine what temperatures were necessary to create them.
Speaking to the LA Times, lead author Sean Hsu compared the process of silica formation to dissolving sugar in coffee: "You put in the sugar and as the coffee gets cold, if you know the relation of the solubility of sugar as a function of temperature, you will know how hot your coffee was. And applying this to Enceladus's ocean, we can derive a minimum [temperature] required to form these particles."
The researchers determined that the silica must have formed under very specific circumstances, including a temperature of approximately 90 degrees Celsius. These incredibly high temperatures, they concluded, were likely the result of hydrothermal vents in Enceladus's underground ocean. Hydrothermal vents can be found on Earth, and are extremely conducive to the advent of microbial life.
"Basically, we think that hot water interacting with rocks leeches out silica," Hsu told The Washington Post, "And as the temperature drops, nanoparticles start to form. Depending on the condition of the silica solution, the particles will form at very particular sizes, like the ones we've detected."
According to Hsu, their research indicates that Enceladus may have all the necessary building blocks for life: "Without sunlight there to provide energy for life, you need something like hydrothermal systems,. They provide energy and warmth, they leech minerals out from rock, and of course they involve liquid water — so the basic building blocks are all there. But of course that's not a guarantee."
It's not a guarantee specifically because we don't know how long the hydrothermal vents have existed on Enceladus, or specifically whether they've been there long enough to support life. "Life needs a really stable environment to evolve in, for a long time," said Hsu. "And we don't know how stable this is, or for how long."
But even so, this is a major breakthrough in the field of astrobiology. If this research is ultimately proven correct, then Enceladus could easily be host to some kind of "primordial soup" within its hydrothermal vents. According to Hsu, this study renders the moon the "second-top object for astrobiology interest" aside from Jupiter's icy moon Europa.