Europa, one of Jupiter’s moons, may not be the prime candidate for alien life that many once thought. Recent research indicates that the underwater world of this icy moon might lack the tectonic activity needed to support life as we know it.
The study suggests that without the movement of tectonic plates, there wouldn’t be enough interaction between rocks and water to create the chemical reactions necessary for microbial life. Paul Byrne, a planetary scientist at Washington University in St. Louis, explains, “Without fracturing and faulting, it’s unclear how energy sources would emerge.”
Europa has a thick icy shell, under which lies a deep ocean. For any potential life to survive there, it would need a way to access energy. Here on Earth, the seafloor’s tectonic movements enable water to dive deep into rocks, creating nutrients through hydrothermal vents. These vents are crucial for supporting oceanic ecosystems.
Byrne’s team used a new model to assess whether tectonic activity occurs on Europa’s seafloor. They considered factors like gravitational tides from Jupiter, the moon’s gradual cooling, and heat convection. Surprisingly, they found that these forces aren’t sufficient to trigger tectonic shifts like those on Earth.
One key finding is about Europa’s orbit. Although it has gravitational influences due to its eccentric path around Jupiter, the required strength to cause tectonic activity is significantly lacking. Interestingly, Europa’s orbital eccentricity is only 0.009—far less than the 0.441 needed to create strong tectonic activity.
In contrast, studies of other celestial bodies, like Mars, show more tectonic activity due to greater contraction—a factor Europa lacks. The rocky core of Europa would need to shrink several kilometers to create fractures in the bedrock, something that isn’t anticipated to happen based on current models.
The absence of major tectonic activity poses challenges for the possibility of life. Hydrothermal vents, often depicted as energetic sources of life-sustaining nutrients on Earth, are unlikely to exist in the same form on Europa. Byrne mentions, “There are alternatives, though,” like cooler hydrothermal systems that may be present, but they’re less energetic and their longevity remains uncertain.
Despite these findings, there could still be alternative sources of nutrients. Radioactive decay is one possibility, albeit one that remains poorly understood on Europa. Another idea is that meteorites could introduce nutrients from the surface ice into the ocean, but it’s unclear if pathways exist through the thick icy shell.
The upcoming NASA Europa Clipper mission aims to uncover these mysteries. This mission will explore whether the ocean beneath Europa’s ice could support any form of life, despite the limitations.”
The insights from Byrne’s study have implications beyond Europa. Similar challenges might exist on other ocean moons. Byrne notes that their findings likely apply to many moons, except for Saturn’s Enceladus, which has demonstrated significant tectonic activity and vent systems.
However, Byrne remains optimistic about the possibility of life. “While our results suggest it’s more complicated, we can’t rule it out entirely,” he insists. The quest to discover life in these hidden oceans continues, underscoring our ongoing fascination with the universe’s potential for life.
The study was published on January 6 in the journal Nature Communications. As we explore further, who knows what secrets Europa yet holds?
