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New evidence that Europa is covered by a deep ocean beneath a shifting icy shell

Many of Jupiter’s moons have long captivated our imagination. Nestled in the shadow of the gas giant, Europa is believed to harbor a massive, hidden ocean beneath its icy shell, a tantalizing prospect for life beyond Earth.

Now, thanks to NASA‘s Juno spacecraft, we have a fresh, high-definition look at this enigmatic world, and it’s revealing more than we ever imagined.

Europa’s deep ocean and icy shell

Europa, one of Jupiter’s largest moons, has fascinated scientists for decades. Its icy surface, unique geological features, and potential for harboring life make it a prime target for exploration.

Europa’s surface is covered by a thick layer of ice, estimated to be about 10-15 miles (15-25 kilometers) thick. Beneath this ice, scientists believe there is a vast ocean of liquid water, possibly containing twice as much water as all of Earth’s oceans combined.

Geological activity and surface features

Europa’s icy shell displays a variety of geological features, including:

  • Ridges and bands: Long, linear cracks and ridges crisscross the surface, some stretching for thousands of miles.
  • Chaos terrain: Regions where the surface ice appears to be broken and re-frozen in a chaotic jumble.
  • Impact craters: Few in number, suggesting a relatively young and dynamic surface that is frequently resurfaced.

Europa’s wandering poles above liquid ocean

Europa is not a static, frozen ball. Juno’s images support the theory of “true polar wander,” a phenomenon where the moon’s icy shell shifts and slides over the liquid ocean below. This is like a giant jigsaw puzzle slowly rearranging itself, with new cracks and ridges forming over time.

“True polar wander occurs if Europa’s icy shell is decoupled from its rocky interior, resulting in high stress levels on the shell, which lead to predictable fracture patterns,” explains Candy Hansen, a Juno co-investigator who leads planning for the JunoCam.

These shifting plates could have implications for the potential habitability of Europa. The movement of the ice could bring nutrients and energy from the ocean to the surface, creating conditions that might support life.

“The Platypus” region

One of the most intriguing features captured by Juno is a chaotic region nicknamed “the Platypus.”

This area has a jumbled landscape with ridges, hummocks, and dark stains. These characteristics hint at recent surface activity and the potential presence of subsurface water.

The Platypus isn’t the only sign of activity on Europa. Juno also captured images that appear to show plume deposits.

These deposits might indicate that water vapor is erupting from the ocean below the ice. These plumes could provide a direct way to sample the moon’s subsurface and search for signs of life.

Future of Juno’s research on Europa

Juno’s flyby of Europa was brief, but it provided a wealth of information to ponder. It’s also a tantalizing preview of what’s to come.

“These features hint at present-day surface activity and the presence of subsurface liquid water on Europa,” said Heidi Becker, lead co-investigator for the Stellar Reference Unit on Juno. 

“The SRU’s image is a high-quality baseline for specific places NASA’s Europa Clipper mission and European Space Agency’s (ESA’s) Juice missions can target to search for signs of change and brine,” Becker concluded.

These missions will carry a suite of instruments designed to study Europa’s composition, surface features, and potential for life. They will map the moon’s surface in unprecedented detail, search for plumes of water vapor, and even attempt to sample the subsurface ocean.

Eternal fascination of Europa

Europa has always been a source of wonder and speculation. It’s a world that challenges our understanding of where life can exist.

The images from Juno have only deepened this fascination. They reveal a dynamic and active moon. Europa has a hidden ocean that could hold the keys to some of the biggest questions in science.

The journey to Europa is just beginning, and it promises to be a thrilling one. As we continue to explore this distant world, we may find that we’re not alone in the universe, that life can thrive in the most unexpected places.

Europa, once a mysterious moon, is now a beacon of hope in our quest to understand the cosmos and our place within it.


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