The NASA Juno mission, initially aimed at studying Jupiter, has recently captured stunning infrared images of Io, Jupiter’s most volcanically active moon. These images reveal the presence of numerous lava lakes, characterized by hot rings surrounding cooler crusts. This discovery sheds new light on the volcanic processes that dominate Io’s surface, providing scientists with invaluable data on the moon’s geologic activity.
Infrared Imagery Sheds Light on Io’s Volcanic Activity
Juno’s Jovian Infrared Auroral Mapper (JIRAM) instrument, initially designed to peer beneath Jupiter’s thick clouds, has captured detailed infrared images of Io. These images show bright white rings of lava with thermal signatures ranging between 450 and 1,350 degrees Fahrenheit (232 and 732 degrees Celsius). The rest of the lake’s surface remains significantly cooler, measuring around minus 45 degrees Fahrenheit (minus 43 degrees Celsius). This stark contrast highlights the dynamic nature of Io’s volcanic activity.
Read More: NASA astronauts stranded in Space due to Boeing’s Starliner malfunctions
Alessandro Mura, a Juno co-investigator from the National Institute for Astrophysics in Rome, stated, “We now have an idea of what is the most frequent type of volcanism on Io: enormous lakes of lava where magma goes up and down.” He added that the lava crust breaks against the walls of the lake, forming the typical lava ring patterns also observed in Hawaiian lava lakes.
Theories Behind Io’s Lava Lakes
Two primary hypotheses have emerged to explain the formation of these lava rings on Io. The leading hypothesis suggests that magma undergoes upwelling in these lava lakes, causing the lakes to rise and fall. When the crust touches the lake’s walls, which can be hundreds of meters tall, the friction causes it to break, exposing the lava along the edge.
A secondary hypothesis posits that magma wells up in the middle of the lake, pushing the crust outward until it sinks along the edge. This process again exposes the lava and forms the characteristic lava rings. Both hypotheses highlight the dynamic and cyclical nature of Io’s volcanic activity, which continues to intrigue scientists.
Juno’s Close Flybys of Io
In May and October 2023, Juno flew by Io, coming within approximately 21,700 miles (35,000 kilometers) and 8,100 miles (13,000 kilometers), respectively. These close flybys allowed JIRAM to capture high-resolution infrared images of Io’s surface. The favorable positions of Juno during these flybys revealed that Io is covered by lava lakes contained in caldera-like features, with about 3% of the observed region being covered by molten lava lakes.
The detailed imagery provided by JIRAM is proving to be one of the most valuable tools in understanding Io’s volcanic landscape. Scott Bolton, principal investigator for Juno at the Southwest Research Institute in San Antonio, emphasized the importance of these findings. “We are just starting to wade into the JIRAM results from the close flybys of Io in December 2023 and February 2024,” he said. Combining these new results with Juno’s longer-term campaign to monitor and map the volcanoes on Io’s never-before-seen north and south poles, JIRAM is offering unprecedented insights into the workings of this tortured world.
Read More: NASA to launch artificial star into orbit by 2029
Io, slightly larger than Earth’s moon, has captivated astronomers since its discovery by Galileo Galilei in 1610. It is the most volcanically active body in the solar system, a result of the intense gravitational pull and tidal forces exerted by Jupiter and neighboring moons. This constant stretching and squeezing create immense heat, driving the volcanic activity observed on Io’s surface.