A group of astronomers led by planetary scientist Carver Bierson from the University of Arizona (USA) presented remarkable findings about Jupiter’s four “Galilean moons.”
These four unique worlds – Io, Europa, Ganymede, and Callisto – are considered “moons of life” and have been the focus of numerous space agencies worldwide, such as NASA and ESA, in the search for extraterrestrial life. Currently, they still possess many potential factors for life. According to Dr. Bierson and colleagues, they were even more conducive to life when they first formed, possibly even hosting liquid water.
The four “moons of life” of Jupiter – Image: NASA
Based on the known data about Jupiter and these giant moons (Ganymede being larger than Mercury), the research team developed a model of their evolution from the early stages of the Solar System.
At that time, the Galilean moons, arranged in a row along Jupiter’s equator, resembled a miniaturized planetary system, slowly forming from the primordial disk of material surrounding Jupiter, just like a new planetary system in the making.
As with other evolving star systems, Jupiter matured, and the four main moons were born, while the disk disappeared. The now energetically rich planet has been shining brightly, though not as brightly as a star, about 10,000 times brighter than it is today.
Unfortunately, the four “moons of life” are situated too close to Jupiter, subjecting them to much more intense radiation than they receive from the Sun. At least the two closest moons, Io and Europa, have had to endure this radiation onslaught.
During its youthful phase, Jupiter became a “killer,” blasting away volatile substances from these “moon worlds,” causing water to evaporate.
Could the volcanic moon Io have once been a “moon planet” born for life? – Image: NASA
As a result, these celestial bodies, once potential habitable planets, underwent drastic transformations, becoming some of the most peculiar celestial objects. For example, Callisto is scarred, with the most heavily cratered surface in the Solar System, appearing to have a composition of half rock and half ice, while Io has the least amount of ice among Solar System moons. Io also holds special interest for the research team, known for its volcanic activity and being the only place outside of Earth where confirmed geological activity exists within the Solar System. However, its geological activity is too violent, turning it into a hellish place.
But the past may have been different. Io might have had a significant amount of icy water after its formation but was “slaughtered” by Jupiter.
If this hadn’t happened, Io could have been a “worthy competitor” to Earth, especially considering previous studies that indicated Io was close enough to Jupiter to experience tidal interactions significant enough to sustain internal processes.
The research was presented at the 54th Lunar and Planetary Science Conference held in Texas, USA.