Despite the Juno spacecraft orbiting Jupiter and its moons for four years, it continues to discover new details about these incredible celestial bodies. This time, the spacecraft managed to “observe” the north pole of one of the strangest objects in our Solar System, the moon of Jupiter Ganymede.
The celestial body is the largest and most massive moon in our galactic neighborhood. With 5,268 kilometers wide. The satellite is made up of water and silicate ice, with an icy shell wrapped around a liquid ocean, with a liquid iron core inside. This nucleus is thought to give Ganymede another primacy: it is the only moon in the Solar System with a magnetospheregenerated by convection in the nucleus.
In the north pole of the celestial body there is a constant rain of plasma caused by the magnetosphere of Jupiter. Ganymede has a negligible atmosphere, therefore much of the plasma is discharged directly to the surface of the moon. Thanks to the newly released infrared images taken by the JIRAM (Jovian Infrared Auroral Mapper) instrument, the effect of the constant plasma rain is clear.
“The ice in and around the north pole of Ganymede was modified by the precipitation of the plasma“, says Alessandro Mura of the National Institute of Astrophysics of our beautiful country.”It is a phenomenon that we got to know for the first time with Juno because we are able to see the north pole in its entirety“.
The ice on the surface of Ganymede, especially at the poles, is very different from what we have on Earth. Is called “amorphous ice“, is distinguished by a lack of long-range order in its atomic arrangement and is mainly produced by the rapid cooling of liquid water.