What lies beneath the icy surface of Jupiter’s moon?
In the search for alien life, what clues does the hidden world underneath Europa hold?
Very often when we think about alien life in our solar system, our minds jump to Martians roaming around the Red Planet. But what if alien life in our solar system was not on a planet, but underneath a moon? Europa is extremely intriguing due to its potential for harbouring life and NASA launched the Europa Clipper on October 14th, 2024 to explore the icy world orbiting Jupiter. The Clipper is scheduled to reach Europa in 2030 and it will find a smooth, bright surface crisscrossed by dark streaks and ridges. The presence of these streaks are one of the main reasons we think Europa could have life and it has to do with what is underneath the icy layer.
Europa’s icy surface consists of large continents of ice shells that move over a subsurface ocean, very similar to Earth’s continents over molten lava. These icy shells scraping each other can cause the ocean from underneath Europa’s surface to erupt into the surface. The scraping causes these dark markings to form all over the surface and also causes something called plumes. Similar to volcanoes on Earth flinging material into the atmosphere, plumes on Europa shoot the subsurface ocean into the atmosphere. The way the Clipper is going to study the ocean is by flying through these “plumes” and collecting samples to analyse, samples which will answer whether Europa could harbour life.
Scientists have always thought that ocean worlds could harbour life, but subsurface ocean worlds have very different features. Scientists believe that Europa’s oceans could be twice the volume of all Earth’s oceans combined and could be kept warm by the moon’s internal heat. Europa orbits near the massive magnetic field of Jupiter which induces tidal forces on the moon, heating up the ocean and perhaps creating hydrothermal vents like back on Earth. The vents on Earth harbour very diverse microbial life and scientists hope that Europa could be home to the same kind of life.
As Europa Clipper journeys to this distant world, it holds the tools to unlock some of Europa’s most profound secrets. Set to fly directly through potential plumes that erupt from beneath the moon’s icy surface, the Clipper will collect samples of the ocean spray, analysing them for key ingredients of life, like salts, organic molecules, and perhaps even hints of microbial activity. Its onboard instruments will also scan Europa’s ice shell to measure its thickness, map surface features, and detect thermal anomalies that may indicate warmer waters below. By investigating the complex interactions between Europa’s icy surface, hidden ocean, and Jupiter’s tidal forces, the Europa Clipper mission aims to answer one of humanity’s oldest questions: could life exist beyond Earth?