Underwater snow reveals clues about Europa’s oceanic world

Underwater snow reveals clues about Europa's oceanic world
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Underwater snow forms in the global ocean and moves underwater, clinging to sunken valleys and inverted ice peaks, according to new research. The same phenomenon happens under the ice shelves on Earth – and it could be that Europa is building its ice crust this way.

The finding, published Monday in the journal astrobiologysuggested that Europa’s ice crust may not be as salty as scientists first thought. Understanding the salt content of the ice crust is crucial as engineers work on the assembly of NASA’s Europa Clipper spacecraft, which is set to launch to Europa in October 2024.

Europa Clipper will use ice-penetrating radar to look under the crust and determine whether the moon’s ocean is potentially habitable for life. Any salt in the ice crust can affect how deep the radar can penetrate, so estimates about the crust’s composition are key.

Clues to the ice crust could also help scientists determine more about Europa’s ocean, salinity, and potential to host life.

Europa’s ice crust sits atop an ocean estimated to be 10 to 15.5 miles (15 to 25 kilometers) thick and possibly 40 to 90 miles (60 to 150 kilometers) deep.

“As we explore Europa, we are concerned with the salinity and composition of the ocean, because that is one of the things that will govern its potential habitability and even the type of life that can live there,” said lead study author Natalie. Wolfenbarger, a PhD student researcher at the University of Texas Institute of Geophysics at the UT Jackson School of Geosciences, said in a statement.

Wolfenbarger is also a graduate student member of the Europa Clipper science team. Researchers at the University of Texas at Austin are developing the spacecraft’s ice-piercing radar.

Europa’s ocean closest to its crust has a temperature, pressure, and salinity similar to water under Antarctica’s ice shelves. previous research suggested.

Researchers have studied two methods of freezing beneath Earth’s ice shelves: dense ice and brittle ice.

Jupiter's moon Europa may have a habitable ice crust

What is the diffrence? As the frozen ice drifts through the supercooled seawater in flakes before settling under the ice shelf, the frozen ice actually grows from the bottom of the ice shelf.

Both of these species result in ice that is less salty than seawater, and the researchers estimated that when they applied this data to the age and scale of Europa’s ice crust, the seawater was even less salty.

Frazil ice may be the most common type in Europe, making the ice crust much purer than previously believed. Frazil ice retains only a small fraction of the salt found in seawater. The purity of the ice crust can affect its strength, ice tectonics, and how heat flows through the crust.

“We can use Earth to assess the habitability of Europa, measure the exchange of pollution between ice and ocean, and find where the water is in the ice,” said study author Donald Blankenship, a senior research scientist at the University of Texas Geophysics Institute. , in a statement. He is principal investigator of the Europa Clipper’s ice-piercing radar instrument.

The finding may suggest that Earth could be used as a model to better understand Europa’s habitability.

Previous missions had observed clouds of water vapor erupting from the ice crust, as shown in this image.

“This paper opens up a whole new set of possibilities for thinking about ocean worlds and how they work,” said Steve Vance, a research scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California. “This lays the groundwork for how we can prepare for the Europa Clipper’s ice analysis.” Vance was not involved in the study.

Meanwhile, work continues on the Europa Clipper spacecraft’s core at the Spacecraft Assembly Facility at NASA’s Jet Propulsion Laboratory.

Measuring 3 meters high and 1.5 meters wide, the core took center stage in the clean room where NASA teams assembled spacecraft such as Galileo, Cassini and Mars rovers.

The mission team is currently assembling the Europa Clipper in High Bay 1, a clean room at NASA's Jet Propulsion Laboratory.

Flight equipment and scientific instruments will be installed on the spacecraft by the end of the year. Next, engineers will run the spacecraft through a series of pre-launch tests.

Europa Clipper will arrive at the Jovian moon in April 2030. Over the course of about 50 planned flights of Europa, the spacecraft will eventually transition from an altitude of 1,700 miles (2,735 kilometers) above the lunar surface to an altitude of just 16 miles (25 kilometers).

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