A NASA spacecraft sees a volcanic explosion on Io, Jupiter’s third-largest moon. NASA

Waves of Lava Caught Sweeping Across Jupiter Moon Io's Massive Volcanic Crater

Swells of lava spreading across the surface of the molten lake at Loki Patera could help explain the periodic changes in brightness seen by astronomers.

May 11, 2017
5:30 PM EDT
This maps chart the the temperature and lava crust age within Loki Patera, a huge volcanic crater on Jupiter's moon Io. The higher temperatures in the southeast (location 3) indicate that new magma was exposed most recently in this location. | Large Binocular Telescope Observatory