Many believed that the core of Jupiter's ocean moon Europa had been formed billions of years ago, just like the rest of its parts. However, a new study suggests it's not the case.
Jupiter's Ocean Moon Europa Has No Fully Formed Core
Jupiter's fourth-largest moon Europa is covered with an icy shell. However, scientists believe that under its ice-covered surface, Europa is home to a saltwater ocean roiling over its rocky mantle.
Kevin Trinh, the new study's lead author and a planetary scientist at Arizona State University in Tempe, said it might have "more liquid water than Earth." Previous studies have suggested that Europa may be livable, Space.com reported.
For instance, undersea volcanoes and hydrothermal vents may help supply heat that supports life and compounds beneficial to biological processes into the ocean. Scientists must comprehend the nature of the Jupiter moon's interior and how it might have changed through time to determine whether such potentially life-supporting activities exist on Europa.
NASA's Galileo spacecraft entered the Jovian system in 1995, and its investigation of Europa's gravity field led to the hypothesis that, like Earth, Europa has a metallic core and a rocky mantle in its interior. Later studies frequently concluded that these layers were generated as, or shortly after, the formation of the Jovian moon.
However, to the researchers' astonishment, they discovered that Europa may have lived much of its life without a completely developed metallic core, assuming it even exists, according to Trinh.
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.
Europa probably developed at far colder temperatures than Earth due to the icy moon's greater distance from the sun, which is one reason it might not have a completely formed core. It 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, Trinh and his colleagues used the comparatively low beginning temperatures of minus 99 degrees Fahrenheit (minus 73 degrees Celsius) to 80 degrees F (26 degrees C) 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," Trinh claimed, it would help make Europa more livable.
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, according to Trinh.
The study was published in the journal Science Advances.
What Is Europa?
Europa is Jupiter's ocean moon. The majority of Europa's surface is water ice, as observed by ground-based observatories, and researchers have discovered compelling evidence that an ocean of liquid water or slushy ice lies beneath the ice crust, NASA reported.
In 1979, two Voyager spacecraft passed through the Jovian system and gave indications that Europa might have liquid water. Then, Earth's ground-based observatories, the Galileo spacecraft, and space telescopes have raised scientists' confidence in the existence of an ocean on Europa.
According to scientists, the ice shell of Europa is between 10 and 15 miles (25 and 60 kilometers) thick and floats atop an ocean between 40 and 100 miles (60 and 150 kilometers) deep; therefore, even though Europa has a diameter of only one-fourth that of Earth, its ocean may hold twice as much water as Earth's seas do.
The immense and unfathomably deep ocean of Europa is considered the best area to look for life outside Earth. Europa's ocean may even be seeping into space, allowing a passing spacecraft to sample it without touching the moon's surface.
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