NASA’s Juno mission is studying Jupiter like no other has done before, peering through its cloud layers and giving us stunning images of the planet. Now … we have the first image of the north pole of its great moon Ganymede.
Ganymede is the only moon that has its own magnetic field and a subsurface ocean with more water than all the surface waters on Earth combined. And that is a lot to say.
The interaction between its surface ice and its magnetic field was one of the reasons NASA chose to make these observations. Plasma from Jupiter’s huge magnetic field travels to the moon, and the magnetic field lines drive the charged particles toward the poles. On Earth, when those particles collide with the atmosphere, we see the spectacular auroras, but Ganymede does not have a significant atmosphere, so the particles hit the icy surface.
As observed by one of Juno’s instruments, JIRAM, the plasma alters the ice. At the equator, the ice is in a crystalline structure. At the pole, the ice is amorphous and the constant bombardment of plasma alters the behavior of the water molecules in the ice with each other.
” It is a phenomenon that we have been able to learn about for the first time with Juno because we can see the North Pole in its entirety, ” explains Alessandro Mura, Juno co-investigator at the National Institute of Astrophysics in Rome.
The images were collected on December 26, 2019, about 100,000 kilometers from the surface of the large moon.
What is to come?
ESA’s JUICE (JUpiter ICy Moons Explorer) probe will set sail in 2022 with the intention of exploring Ganymede, Europa and Callisto from 2029.
Reference: NASA JET PROPULSION LABORATORY
