But still, defiantly, these alien oceans remain liquid.
sea wrapped in mirrors
Scientists believe that the small number of moons orbiting Jupiter and Saturn, and even those rotating around Uranus and Neptune, may also be in the ocean. Callisto, with its giant Ganymede and crater tracks, produces a weak magnetic signal similar to Europa’s. Saturn’s foggy Titan also probably has an ocean of liquid water underground. These are “the five that most scientists in the community are pretty confident in,” he said. mike soria planetary scientist at Purdue University.
So far, Enceladus is the only planet with absolute certainty about the oceans. “That’s easy,” he said. carly howetta planetary scientist at the University of Oxford.
In the 1980s, some scientists suspected that Enceladus had a plume. Saturn’s E ring was so clean and shiny that something must be leaking out into space, probably from one of its moons, constantly updating it. After Cassini finally witnessed the planet-adorning magic in action, scientists briefly speculated that the moon’s south pole plume could be the result of sunlight evaporating ice inside the moon’s shell. questioned. It’s probably similar to dry ice, which boils and evaporates when heated by sunlight.
“For a while there was a debate about whether we even needed the ocean at all,” Nimmo said. “That’s when it really clicked.” [Cassini] They flew through the plume and found salt, or sodium chloride. That is the sea. ” There was still a possibility that these plumes would erupt from smaller, more isolated oceans. But further Cassini observations revealed that Enceladus’ shell is rocking back and forth so violently that it must be separated from the moon’s deeper interior by a global ocean.
The plume also emitted hydrogen and quartz, a sign of deep-sea hydrothermal vent activity. Frank Postberg, a planetary scientist at the Free University of Berlin. On Earth, such vents are used to power ecosystems that exist outside the reach of sunlight, communities that scientists once thought could not exist in a world dependent on photosynthesis. Generates the necessary heat and chemicals.
But what is powering a ventilation system powerful enough to heat the entire ocean? Another moon, this one of the fiery kind, gives us clues about They will provide it to you.
Eternal hell tide
In June 1979, a month before Voyager 2 approached Europa, scientists said: announced Voyager 1 caught a glimpse of a giant umbrella-shaped plume swirling above Io, the remains of several volcanic eruptions.
This observation should have been puzzling. Volcanic activity requires an internal heat source, and Io, like other icy moons, was supposed to be just an ember. But a few months ago, an independent team of scientists conducted an accurate analysis. predicted Io may be a highly active volcanic world.
