The geysers of Enceladus are one of the most interesting discoveries of the Cassini spacecraft and now there are more indications that they have been going on for a few decades at least.
The latest piece of evidence is actually historical and comes from philosophy professor and planetary exploration enthusiast Ted Stryk, who’s been busy looking at the images taken by Voyager in 1980. He processed some of these images and spotted plumes erupting from the southern pole of the Saturnine moon.
“I added up and averaged the images and did my best to remove instrument noise in order to bring the most I could out of an image that is only a few pixels across. This allowed me to get a result of which I am reasonably confident,” Stryk told IFLScience.
The discovery, reported in a blog post for the Planetary Society, is important because it shows that the geysers have been there for over three decades and extends our certainty of activity by the icy moon beyond the 12 years of analysis by the Cassini Mission.
It is interesting to note that the first suggestion of potential eruption from Enceladus comes from a study that used the Voyager data. The researchers suggested Enceladus as the culprit for the E ring of Saturn based on several indirect pieces of evidence. This was then proved in 2005, by Cassini. And yet, the proof of Enceladus' geysers was already there, they just didn’t have the tech to see it.
“There are thousands and thousands of images, and the original work on them was done with tools that would seem laughable to anyone today with a smartphone,” Stryk continued. “We can pull far more out of early datasets than was possible at the time. Also, as we make new discoveries with newer instruments, we discover new phenomena that people in the past may have never thought to look for.”
Stryk has been wondering about historical documentation for Enceladus’ geysers since they have been announced so he looked at both the Pioneer and Voyager probes. The former were no good but there was a good chance that the latter might have caught something. His first search, though, didn’t bear any fruit.
In 2015, he was inspired by a talk on the moons of Pluto serendipitously showing up in New Horizons images of the dwarf planet to check for potential guest appearances of Enceladus. When he started looking for it again last fall, he found what he was looking for.
Who knows what other interesting discoveries might be hiding inside archived data just waiting for somebody to put in the work to find them.
Zoomed in version of the main picture. NASA / JPL-Caltech / Ted Stryk
[H/T: Planetary Society]