British scientists have published the most detailed images of the icy surfaces of Jupiter’s two largest moons, Europa and Ganymede.
The team of planetary scientists from the University of Leicester’s School of Physics and Astronomy, led by doctoral student Oliver King, used the European Southern Observatory’s Very Large Telescope (VLT) in Chile to observe and map the moons’ surfaces.
The latest images from the observatory provide new insights into the processes that affect the chemical composition of the massive moons, as well as the geological features of the moons, such as the long, fault-like lines that cross the surface of Europa.
The images show the mixture of chemicals that form the icy surfaces on Jupiter’s largest moons, Europa and Ganymede, two future destinations for new missions to the giant planet system.
It is noteworthy that Ganymede and Europa are two of the four largest moons orbiting Jupiter, known as the Galilean moons.
Europa and Ganymede belong to the group of 79 natural satellites orbiting Jupiter
Europa is similar in size to Earth’s moon, while Ganymede is the largest moon in the entire solar system.
During the observations, sunlight reflected from the surfaces of Europa and Ganymede was recorded at different infrared wavelengths, producing reflectance spectra. The scientists then analyzed the results using a computer model that compares each observed spectrum with the spectra of different substances measured in laboratories.
In addition, they mapped the distributions of different materials on the surface, King said. As a result, the experiment revealed that Europa’s crust consists mainly of frozen water ice, while other non-ice materials have been recorded polluting the surface.
Ganymede’s observations, published in JGR: Planets, show how the surface is made up of two main types of terrain.
It is noteworthy that the small areas have large amounts of water ice, and the old areas are composed of unknown dark gray matter.
The ice areas, shown in blue in the images, include the polar ice cap and craters, and an impact event revealed fresh clean ice of the Ganymede crust.
The team mapped how the ice grains in Ganymede vary across the surface and the potential distributions of a variety of different salts, some of which may originate from within the moon itself.
“The powerful telescope has enabled detailed mapping of Europa and Ganymede, observing features less than 150 km in diameter, all at distances exceeding 600 million km from Earth,” King said. Until now, mapping at this precise scale was only possible by sending a spacecraft to Jupiter to closely monitor satellites.
