The troughs that dominate the surface of the solar system’s largest moon Ganymede may have been caused by a collision with a massive object up to 90 miles/150 kilometers wide.
That’s according to a new paper published on pre-print service arxiv.org by Japanese scientists. If the theory is true then it’s the largest impact structure identified so far in the solar system.
Ganymede is the largest of Jupiter’s estimated 79 moons and bigger than both dwarf planet Pluto and the planet Mercury. Its diameter is 3,273 miles/5,268 kilometers. It’s the only moon we know that has a magnetic field. It also has an atmosphere and is suspected of having an underground saltwater ocean.
Ganymede’s surface is pock-marked, grooved and patterned. The paper argues that the furrows across its surface are part of aa concentric system of tectonic troughs. “If this multi-ring structure is of impact origin, this is the largest impact structure identified so far in the solar system,” reads the paper. “The estimate of the impactor size is difficult, but an 150km-radius impactor is consistent with the observed properties of furrows.”
The scientists used images taken in 1979 by NASA’s Voyager 1 and 2 probes as well as in images taken by NASA’s Galileo spacecraft, which orbited Jupiter between 2001 and 2003.
NASA’s Juno spacecraft photographed Ganymede during a close flyby in June 2021.
The theory could be confirmed by future explorations of Jupiter’s icy moons, most notably by the European Space Agency’s JUICE (Jupiter Icy moon Explorer) mission.
JUICE is scheduled to launch between April 5-25, 2023 on an Ariane 5 rocket from Europe’s Spaceport in French Guiana, South America. It will arrive in 2031 and spend three and a half years examining two of Jupiter’s other moons Europa and Callisto before going into orbit of Ganymede in September 2032. It will become the first spacecraft to orbit a moon other than Earth’s Moon.
Wishing you clear skies and wide eyes.