Io — the innermost of the four Galilean moons of Jupiter and the fourth-largest moon in our Solar System — is approximately 2,556 miles (3,630 km) across.

Aside from Earth, it is the only known place in the Solar System with volcanoes erupting hot lava like that on our planet.

This intense geological activity is the result of heat produced by a gravitational tug-of-war between Jupiter’s gravity and the smaller but precisely timed pulls from Europa and Ganymede.

Past NASA missions that have visited the Jovian system (Voyagers 1 and 2, Galileo, Cassini and New Horizons), along with ground-based observations, have located over 150 active volcanoes on Io so far.

Planetary researchers estimate that about another 250 or so are waiting to be discovered.

This image from NASA’s Juno spacecraft highlights the location of the new heat source close to the south pole of Io. The scale to the right of image depicts of the range of temperatures displayed in the infrared image. Higher recorded temperatures are characterized in brighter colors — lower temperatures in darker colors. Image credit: NASA / JPL-Caltech / SwRI / ASI / INAF / JIRAM.

“The new Io hotspot Juno picked up is about 200 miles (300 km) from the nearest previously mapped hotspot,” said Juno co-investigator Dr. Alessandro Mura, of the National Institute for Astrophysics in Rome, Italy.

“We are not ruling out movement or modification of a previously discovered hot spot, but it is difficult to imagine one could travel such a distance and still be considered the same feature.”

The infrared data were collected on December 16, 2017, by Juno’s Jovian Infrared Auroral Mapper (JIRAM) instrument when the spacecraft was about 290,000 miles (470,000 km) from Io.

Dr. Mura and colleagues will continue to evaluate these data as well as JIRAM data that will be collected during future — and even closer — flybys of the Jovian moon.

Source: Sci News