From nasa Juno Jupiter probe It has captured unprecedented views of the largest moon in the solar system.
During a flyby close to Jupiter on December 26, 2019, Juno mapped the regions of the north pole of the icy satellite Ganymede in infrared light, something no other spacecraft had ever done before.
The data, which Juno collected using his Jovian Infrared Auroral Mapper (JIRAM) instrument, shows that the northern reaches of Ganymede are very different from the places closest to the moon’s equator, which is larger than the planet Mercury.
Related: In photos: the incredible views of Jupiter from Juno
“The JIRAM data shows that the ice in and around the north pole of Ganymede has been modified by plasma precipitation,” Alessandro Mura, a Juno co-researcher at the National Institute of Astrophysics in Rome, he said in a statement. “It is a phenomenon that we have been able to learn for the first time with Juno because we can see the North Pole in its entirety.”
This plasma consists of charged particles from the sun, which have been trapped by Jupiter’s powerful magnetic field. Unlike any other moon, the 5,274-mile-wide (5,269-kilometer) Ganymede has its own magnetic field, which channels plasma to its poles.
A similar phenomenon occurs here on Earth, which explains why the auroras occur at high latitudes on our planet. But Ganymede has no atmosphere to obstruct and be illuminated by these particles, so they crash into ice on and around both poles.
As a result, the Ganymede polar ice has been hit in an amorphous state on a structural level. This battered ice has a different infrared signature than highly ordered crystalline ice at lower latitudes, mission team members said.
The $ 1.1 billion Juno probe launched in August 2011 and arrived at Jupiter in July 2016, on a mission to help scientists better understand the composition, structure, formation, and evolution of the giant planet.
Juno circles Jupiter in a highly elliptical orbit, gathering a variety of data during close passes that occur every 53.5 Earth days. During the meeting in December 2019, the north pole of Ganymede was in sight of Juno. The mission team then reoriented the probe, allowing it to study the mysterious region with JIRAM and other instruments.
Juno collected about 300 infrared images, from a distance of approximately 62,000 miles (100,000 km). The images have a resolution of about 14 miles (23 km) per pixel, mission team members said.
“These data are another example of the great science that Juno is able to observe when observing Jupiter’s moons,” Giuseppe Sindoni, program manager of the JIRAM instrument for the Italian Space Agency, said in the same statement.
Mike Wall is the author of “Out There” (Grand Central Publishing, 2018; illustrated by Karl Tate), a book on the search for extraterrestrial life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.
