Scientists solve decades-long mystery about why Saturn appears to change its spin

Link to the science paper in the Journal of Geophysical

Scientists have finally solved a long-standing puzzle about why Saturn seems to spin at different speeds. Earlier measurements suggested the planet’s rotation was changing, which is physically impossible. Research led by Professor Tom Stallard at Northumbria University revealed that the apparent variation is not due to Saturn’s rotation but is caused by winds in its upper atmosphere. These winds create electrical currents that affect the planet’s aurora, producing misleading signals.

The new study, using the James Webb Space Telescope, observed Saturn’s northern aurora continuously for a full Saturn day. By measuring the infrared glow of trihydrogen cations—molecules in the upper atmosphere—the team produced highly detailed maps of temperature and particle density, far more precise than previous observations. These maps confirmed that the aurora itself heats the atmosphere in a specific region, generating winds. These winds then produce currents that feed back into the aurora, creating a self-sustaining cycle, like a planetary heat pump.

Video Credit: NASA/ESA/CSA, Tom Stallard (Northumbria University), Melina Thévenot, Macarena Garcia Marin (STScI/ESA).