WASHINGTON, April 15 (IANS) Scientists have provided an explanation for how earthquakes could be the source of the fuzzy, smooth terrain on the moons orbiting Jupiter and Saturn.
Many of the ice-covered moons orbiting the giant planets in the far reaches of our solar system are known to be geologically active.
Jupiter and Saturn have such strong gravity that they stretch and pull on objects orbiting them, causing earthquakes that can break the crusts and surfaces of the moon.
New research shows for the first time how these earthquakes can trigger landslides that result in remarkably smooth terrain.
The study, published in the journal Icarus, identifies the relationship between earthquakes and landslides, and sheds new light on how icy moon surfaces and textures evolve.
On the surfaces of icy moons like Europa, Ganymede and Enceladus, it is common to see steep ridges surrounded by relatively flat, smooth regions.
Scientists have hypothesized that these spots are caused by liquid flowing from glacial volcanoes. But how this process works when surface temperatures are so cold and inhospitable to liquids has remained a mystery.
The simple explanation shown in the study does not involve liquid on the surface. Scientists have measured the dimensions of steep ridges, which are thought to be tectonic faults (like those on Earth)—steep slopes that occur when the surface breaks along a fault line and one side drops.
By applying the measurements to seismic models, they estimated the strength of past earthquakes and found that they can be strong enough to lift debris that then falls downslope, where it spreads, smoothing out the landscape.
We found that the shaking of the surface from earthquakes would be sufficient to cause surface material to rush downhill in landslides. “We estimated the magnitude of moonquakes and the extent of landslides,” said lead author Mackenzie Mills, a graduate student at the University of Arizona in Tucson.
“This helps us understand how landslides can shape the lunar surfaces over time,” added Mills, who conducted the work during a series of summer exercises at NASA’s Jet Propulsion Laboratory in Southern California.
NASA’s upcoming Europa Clipper mission, heading for Jupiter’s moon Europa in 2024, will give the search a big boost, providing images and other science data. After reaching Jupiter in 2030, the spacecraft will orbit the gas giant and make about 50 flybys of Europa.
The European Space Agency’s newly launched JUpiter ICy Moon Explorer, or JUICE, mission aimed at finding alien life on the icy moons of Jupiter’s large ocean-bearing moons — Ganymede, Callisto and Europa — may also add to the search. It will take the spacecraft eight years to reach the largest planet in the solar system in 2031.
– Jans
rvt/pgh
