New Findings Show Constantly Collapsing Atmosphere On Jupiter's Moon Io

We'd expect most new discoveries about Jupiter to be coming from the Juno spacecraft, which entered orbit around the planet early last month, but today we're hearing about a fascinating new find that Juno had nothing to do with. Scientists at the Southwest Research Institute have discovered that the atmosphere around Jupiter's moon Io is in a constant state of flux, collapsing and rebuilding once every day.

Obviously, a day on Io is going to be a bit different than one here on our humble space rock, with an Io day clocking in at 1.7 Earth days. However, during each day on Io, it's eclipsed by Jupiter for about two hours, moving into the massive planet's shadow and out of the sun's rays. It's then that Io's atmosphere, which is mostly comprised of sulfur dioxide, cools and settles on the moon's surface.

Once Io is hit by sunlight, the sulfur dioxide warms up and begins to rise again, reforming the atmosphere around the moon once more. Scientists have suspected something like this was happening on Io, but up until now, they weren't able to observe it. The team from Southwest Research Institute, which was lead by Constantine Tsang, were able to confirm this is happening by observing Io as it entered and exited eclipse using the Gemini North telescope in Hawaii and the Texas Echelon Cross Echelle Spectrograph (TEXES).

With those tools, they didn't require Io to be in sunlight to observe the changes, which was previously a roadblock to confirming this suspicion. Instead, they performed their study by using TEXES to measure Io's atmosphere through heat radiation and Gemini North to detect the atmosphere's changing heat signature. Tsang and John Spencer, who also worked on the study, say these new findings should give scientists a better idea of how the emissions from Io's heavy volcanic activity affect the Jupiter system.

The study was published in the Journal of Geophysical Research under the title "The collapse of Io's primary atmosphere in Jupiter eclipse."

SOURCE: Southwest Research Institute