I’ve talked about Ganymede quite a bit recently, especially if you watched our Minecraft Monday show back in December. We added a few features onto Ganymede in our Minecraft solar system based on the research of the past few years, including an atmosphere with aurorae and a subsurface ocean.

Yes, Ganymede is another icy world, and new research published in the Journal of Geophysical Research: Planets uses data collected from NASA’s Juno Mission to evaluate some of that ice. The team involved used the Jovian Infrared Auroral Mapper (JIRAM) to take images and spectra of Ganymede. In particular, they looked at the north polar region. Juno was about 100,000 kilometers away, so JIRAM was able to map at an impressive resolution of 23 kilometers per pixel. From a collection of images taken at various angles, researchers compared the different brightness levels and the illumination geometry and developed a model for the surface reflectance. They also extended the current map of global water ice to these polar regions.

The biggest result from this paper is the discovery that there are likely larger ice grains in relatively fresh craters, a result that needs further explanation. Lucky for us, we told you last week that NASA extended the Juno mission, and Ganymede is going to be on the receiving end of more flybys that will be even closer. We’re excited to see where this research leads.

More Information

Eos article

“Infrared Observations of Ganymede From the Jovian InfraRed Auroral Mapper on Juno,” A. Mura et al., 2020 November 4, Journal of Geophysical Research: Planets