Jupiter Europa’s moon surface shaken by small impacts

Jupiter Europa’s moon and its world ocean may currently have conditions suitable for life. Scientists are studying the processes on the icy surface as they prepare to explore.

It’s easy to see the impact of space debris on our Moon, where the ancient battered surface is covered in craters and scars. Jupiter’s icy moon, Europa, withstands a similar shock, as well as a punch of super intense radiation. As the top surface of the icy moon flips over, matter brought to the surface is zapped by high-energy electron radiation accelerated by Jupiter.

NASA-funded scientists are studying the cumulative effects of small impacts on Europe’s surface as they prepare to explore the distant moon with the Europa Clipper mission and investigate the possibilities of a future lander mission. Europa is of particular scientific interest because its salty ocean, which lies beneath a thick layer of ice, may currently have conditions suitable for existing life. This water could even make its way through the icy crust and onto the moon’s surface.

New research and modeling estimate how far this surface is disturbed by the process called “impact gardening”. The work, published on July 12 in Nature astronomy, estimates that the surface of Europe has been agitated by small impacts to an average depth of about 12 inches (30 centimeters) over tens of millions of years. And any molecules that can be categorized as potential biosignatures, which include chemical signs of life, could be affected at that depth.

This is because the impacts would cause some material to rise to the surface, where the radiation would likely break the bonds of any potential large and delicate molecules generated by biology. During this time, some material on the surface would be pushed down, where it could mix with the basement.

“If we’re hoping to find pristine chemical biosignatures, we’ll have to look below the area where the impacts have been gardened,” said lead author Emily Costello, planetary researcher at the University of Hawaii at Manoa. “Chemical biosignatures in areas shallower than this area may have been exposed to destructive radiation.”

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While impact gardening has long been seen as likely taking place on Europe and other airless bodies in the solar system, the new modeling provides the most complete picture of the process to date. In fact, it is the first to take into account the secondary impacts caused by the debris falling on the surface of Europe after being lifted by a first impact. Research shows that mid to high latitudes in Europe would be less affected by the double whammy of impact gardening and radiation.

“This work expands our understanding of fundamental processes on the surfaces of the solar system,” said Cynthia Phillips, Europa scientist at NASA’s Jet Propulsion Laboratory in Southern California and co-author of the study. “If we are to understand the physical characteristics and how planets evolve in general, we have to understand the role that gardening has in reshaping them. “

Managed by JPL for NASA, Europa Clipper will help develop this understanding. The spacecraft, targeting a launch in 2024, will perform a series of close flights of Europe in orbit around Jupiter. It will carry instruments to study the moon in depth, as well as to sample dust and gases that are projected above the surface.