Europa's Mysterious Core: New Study Suggests Lack of Formation

Europa, Jupiter's fourth-largest moon, has been the subject of intense study for years. A new study has shed light on the moon's mysterious core. Scientists have long believed that Europa's core formed billions of years ago, much like the rest of the moon. However, the latest research suggests that Europa may not have a fully formed core. This article explores the details of the new study and what it means for the possibility of life on Europa.

Europa's Composition

Europa is covered by an icy shell, but scientists believe that beneath the surface lies a saltwater ocean that roils over its rocky mantle. The moon's surface is mainly composed of water ice, and researchers have discovered compelling evidence that an ocean of liquid water or slushy ice lies beneath the ice crust. Europa's surface is between 10 and 15 miles thick and floats atop an ocean between 40 and 100 miles deep. This means that Europa's ocean may hold twice as much water as Earth's seas.

A photograph of the surface of the Jovian moon Europa. The image was taken by the Juno probe during its flyby on September 29, 2022, then processed and colorized by a citizen scientist. (Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Thomas Thomopoulos)

Europa's Habitability

Europa is known as a potentially habitable ocean world. Previous studies have suggested that Europa may be livable. For instance, undersea volcanoes and hydrothermal vents may help supply heat that supports life and compounds beneficial to biological processes into the ocean. To determine whether such potentially life-supporting activities exist on Europa, scientists must comprehend the nature of the moon's interior and how it might have changed over time.

The New Study

The new study, published in the journal Science Advances, outlines the analysis of the evolution of Europa. The findings suggest that Europa did not have a core for most of its existence. Previous studies suggested that Europa has a metallic core and a rocky mantle in its interior, much like Earth. Scientists assumed that Europa's layers were clearly defined around the same time that it formed.

However, the new study challenges this assumption. The researchers discovered that Europa may have lived much of its life without a fully formed metallic core, assuming it even exists. The Galileo spacecraft, which entered the Jovian system in 1995, analyzed Europa's gravity field and suggested that the moon's interior is made up of a metallic core and a rocky mantle, much like Earth. Later studies concluded that these layers were generated as, or shortly after, the formation of the Jovian moon.

To the researchers' astonishment, they found that Europa may have spent most of its life without a fully-formed metallic core. A 2021 study that reexamined the Galileo data suggested that Europa may be smaller around its center than previously believed. Whether it has a fully developed core is a question that remains unanswered.

Set to launch in 2024, NASA’s Europa Clipper will travel to Jupiter’s moon Europa to investigate whether the moon has conditions necessary to support life. The data the spacecraft collects will help researchers learn more about the availability and accessibility of the ingredients for life on the moon. (Image Credit: NASA/JPL-Caltech)

Core Formation

Europa probably developed at far colder temperatures than Earth due to the icy moon's greater distance from the sun. This suggests that Europa's constituent parts may not have melted and split into a metallic core and rocky mantle when they came together. In their computer simulations, the researchers used relatively low beginning temperatures to determine how temperatures in Europa's interior altered over 4.5 billion years.

The researchers discovered that water may have progressively ascended from Europa's mantle within the first 500,000 years following its formation, causing the ocean and icy shells to form. If Europa has a metallic core, it presumably began to include at least a billion years after the moon was created. The metallic core may have progressively melted throughout Europa's existence due to tidal churning caused by Jupiter's gravitational pull and heat from radioactive elements.

The researchers speculated that Europa may still be progressively dividing into several layers. Since the emergence of a metallic core "could deliver a heat pulse to the rocky mantle," it would help make Europa more livable.

Europa Clipper Mission

To improve our knowledge of how mass is distributed inside Europa, which is related to the existence of Europa's metallic core, NASA's upcoming Europa Clipper mission may help scan the Jovian moon's gravity. The Europa Clipper mission aims to determine whether Europa is habitable and to investigate the moon's potential for harboring life. The spacecraft is expected to launch in the mid-2020s and arrive at Europa in the late 2020s.

The new study challenges previous assumptions about Europa's metallic core. The researchers found that Europa may have spent most of its life without a fully-formed metallic core, which could impact the moon's habitability. The emergence of a metallic core could deliver a heat pulse to the rocky mantle, making Europa more livable. NASA's upcoming Europa Clipper mission may help improve our understanding of Europa's core and whether the moon is habitable.