“This is the closest a spacecraft has come to this gigantic moon in a generation,” Juno principal investigator Scott Bolton of the Southwest Research Institute in San Antonio said in a statement. “We are going to take our time before drawing scientific conclusions, but until then we can just be amazed at this celestial wonder: the only moon in our solar system larger than the planet Mercury.”
A color portrait of Ganymede
NASA experts too will soon create color images from Juno data using red and blue filters, which will provide a color portrait of the moon.
Since Ganymede has no atmosphere, the surface of its poles is constantly being bombarded by plasma from Jupiter’s magnetosphere, which has a dramatic effect on the moon’s ice. The ice sheet on the outside is very thick, perhaps 500 miles thick.
The Juno images will also be compared with those taken by the Galileo probe between 2005 and 2004, and by the Voyager probe in 1979, to see if there have been any changes during this time.