According to a new study published in the journal Astrobiology, the crust of Jupiter’s ice moon Europa, may have been partially formed by a fluffy buildup of ice crystals known as “frazil ice.”
Europa’s icy crystals suggest that the shell of Jupiter’s famous ice moon was formed in part by pure underwater snow that floats up rather than falls down.
This frazil ice, which also forms beneath Earth’s ice sheets, has a fraction of the salt found in ice that forms on the ice shelf itself, implying that Europa’s ice sheets may be less salty than previously thought.
According to Natalie Wolfenbarger, a graduate student researcher at the University of Texas Institute for Geophysics and the lead author in the study of exploring Europa, the salinity and composition of the ocean are the epitome of the study.
“When we’re exploring Europa, we’re interested in the salinity and composition of the ocean, because that’s one of the things that will govern its potential habitability or even the type of life that might live there,” she said.
According to NASA, astrobiologists identify Europa as one of the most intriguing objects in the solar system. The moon is covered by an ocean forty to one hundred miles (60 to 150 kilometers) deep, capped off by an ice crust ten to fifteen miles (15 to 25 km) thick.
NASA also claims, Europa’s surface-wide ocean may hold about twice the water as all of Earth’s oceans although it is a quarter of the size of Earth. This makes Jupiter’s moon an intriguing place to search for extraterrestrial life.
New Nasa Orbiter ‘Europa Clipper’ to be launched to aid study
Scientists at the University of Texas at Austin are leading the development of a new NASA orbiter, the Europa Clipper, set to launch in October 2024.
The ice-penetrating radar instrument will fly by the ice moon to see if it might be a suitable habitat for life by peering into the ice sheet and the ocean just beneath it.
The efforts of this research are aimed at understanding how the ice sheet might be structured.
They used Earth as an analogy, looking at the two primary ways that ice originates beneath the ice sheets of Antarctica. Congelation ice is one type that develops from the ice shelf’s surface. The second type of ice, known as frazil ice, develops in frigid seawater and drifts upward as flakes like reverse snow before getting stuck beneath the ice sheet.
Europa likely to have a low-temperature gradient
Like Antarctica, Europa is likely to have a low-temperature gradient, meaning the temperature changes little with depth.
Analyzing the observed conditions, Wolfenbarger found, that frazil ice is quite common, particularly in spots where the ice thins in rifts or fractures. This is also common on Europa, and it could make a big difference in the composition of the moon’s ice shell.
Whereas congelation ice might contain ten percent of the salt of the surrounding seawater, frazil ice is far purer, containing only 0.1 percent of the salt in the seawater from which it forms.
Not only could this low-salt ice affect the structure and strength of Europa’s ice crust, but it could also impact the efficiency by which Clipper’s radar can penetrate the ice.
In a statement, Steve Vance, a research scientist at NASA’s Jet Propulsion Laboratory (JPL) said that “this paper is opening up a whole new batch of possibilities for thinking about ocean worlds and how they work.”
“It sets the stage for how we might prepare for Europa Clipper’s analysis of the ice,” he added—although he was not involved in the study.