A San Antonio scientist will lead a team that will use the James Webb Space Telescope to better study the potential habitability of one of Saturn’s ocean-world moons, Enceladus.
Southwest Research Institute’s Christopher Glein, a planetary scientist and geochemist at the San Antonio-based institute, has been studying the tiny moon for 15 years. Glein has already been part of a team that used the Webb telescope in the first round of research projects given coveted access to the instrument. The largest and most powerful space telescope developed, the Webb telescope was launched into space in December 2021.
During his previous viewing of Enceladus, Glein and the team observed a towering jet of water shooting off of the icy moon’s surface. The 6,000-mile-long plume indicates the presence of frozen volcanoes where ice flows like lava. Because of the time it takes to move the Webb telescope and get it into a favorable position, the team was able to view Enceladus only for four minutes.
But it was a tantalizing glimpse that led Glein to seek more telescope time to expand what is known about the icy moon.
“It would be really exciting” if there is life on Enceladus, Glein said. “If we found it was inhabited, it would be a huge discovery.”
During the next study, the team will study Enceladus’ surface and the geyser to better understand the chemical compounds of the moon and to learn more about the habitability of its environment.
Saturn has 146 moons, 62 of which were discovered just this year. The moons range in size from larger than the planet Mercury — the massive Titan — to as small as a sports arena. Enceladus is just 314 miles across — small enough to fit within the length of the United Kingdom. Saturn’s moons differ greatly in their composition, from icy giants with subsurface oceans to small, heavily cratered rocky worlds.
Titan and Enceladus are the only two moons viewed as having the chemistry to possibly host life, with Enceladus being more favorable.
Enceladus’ water plume holds an intriguing chemical clue.
“We call it Cold Faithful — like Old Faithful,” the famous geyser in Yellowstone Park, Glein said. “This plume is basically giving us free samples of Enceladus’ ocean, which can allow us to study its chemistry.”
Understanding the ocean’s chemistry will allow scientists to better understand if the moon has the favorable building blocks that could support life, Glein explained.
Within the next year, the team will get one hour to observe the moon, said Geronimo Villanueva of NASA’s Goddard Space Flight Center. Villanueva led the previous study and was the lead author of a paper resulting from the team’s observations. The Argentina native is well-known in the astronomy field for his work mapping water on Mars. He will be working with Glein and others on the subsequent study.
Submitting proposals is “an extremely competitive process,” Villanueva said about the group’s efforts to secure more telescope time to view Enceladus. “Only small fractions of time are given out, so the fact it got so much time is a sign of the significance of this study.”
What is known today about Enceladus is mostly from NASA’s Cassini mission, Glein said. The Cassini spacecraft, launched in 1997, spent 20 years in space — 13 of them exploring Saturn. When Cassini’s fuel supply was spent, it was directed to plunge into Saturn’s atmosphere on Sept. 15, 2017. It continued sending data until it vaporized, according to NASA.
Cassini first started collecting data on Enceladus and its largest south pole geyser — Cold Faithful — in 2005, Glein said. The spacecraft proved that Enceladus is an extremely active moon that hides a global ocean of salty liquid water beneath its crust. The jets of icy particles it spews into space from cracks in that crust are laced with simple organic chemicals. Some of that water falls back to Enceladus, while some of it escapes, forming one of Saturn’s vast rings.
In addition to learning more about Enceladus’ habitability, Glein’s study will help scientists learn more about other icy moons and planets within the solar system, said Silvia Protopapa, another SwRI scientist and an expert in the compositional analysis of icy bodies. Protopapa, who participated in the previous study, is one of the 100-plus SwRI scientists in the institute’s Solar System Science and Exploration Division in Boulder, Colorado.
The upcoming study “will set a reference point in what to look for when studying icy bodies in the solar system,” she said. “This serves as a stunning testament to Webb’s extraordinary abilities.”
