NASA’s Juno Peers Beneath Io’s Surface

NASA’s Juno spacecraft has captured a new look beneath the surface of Io, Jupiter’s volcanic moon, using data from its Microwave Radiometer, or MWR. According to a monitored public feed from NASA Breaking News, the map shows heat rising from just below Io’s surface, offering another view of the moon’s active interior.

The observation relies on the MWR instrument aboard Juno, which is designed to detect microwave emissions rather than visible light. NASA notes that while infrared instruments can measure temperatures at the moon’s surface, the MWR’s lowest-frequency microwave channels, at 0.6 and 1.25 gigahertz, can probe deeper below the surface, reaching between about 6 and 30 miles, or roughly 10 to 50 kilometers. That capability allows scientists to examine heat sources that are hidden from standard surface imagery.

Io is known as the most volcanically active body in the solar system, and Juno’s measurements help reveal how heat moves through its crust. The NASA image described in the feed presents the radiometer data as a map, with the warmer signals indicating energy from beneath the surface rather than only from the moon’s outer layer. The result adds to the spacecraft’s continuing investigation of Jupiter and its moons.

Juno has been studying the Jovian system for years, and its instrument suite gives researchers multiple ways to examine the environment around the giant planet. In this case, the Microwave Radiometer is providing information that complements infrared observations, creating a more complete picture of Io’s thermal behavior. By comparing different wavelengths, scientists can better distinguish between surface temperature and subsurface heat.

The NASA Breaking News post highlighted the MWR’s ability to see below the surface using the lowest-frequency channels, underscoring why the instrument is valuable for studying worlds with complex geology. On Io, those readings can help scientists track where heat is escaping and how deep the warm regions extend beneath the crust.

The image and description were distributed through a monitored public feed from NASA, which continues to share findings from Juno as the mission examines the Jupiter system. The new Io map is part of that stream of updates, showing how spacecraft instruments can reveal hidden features on distant worlds without direct drilling or landing.

Source: NASA Breaking News - https://science.nasa.gov/photojournal/nasas-juno-peers-beneath-ios-surface/