Like Earth, the upper atmospheres of gaseous planets such as Saturn, Jupiter, Uranus and Neptune are very hot. But unlike Earth, the sun is too far away to be the main source of heat for these planets. Its source of heat is one of the great puzzles in planetary science.
Using data collected by NASA’s Cassini probe in the final stages of its mission, scientists have found a viable explanation: the aurora on the planet’s north and south poles.
The current generated by the correlation between the solar wind and charged particles from Saturn’s moons stimulates the aurora and heats up the upper atmosphere. The temperature data collected by Cassini show that the peak temperature is close to the aurora, showing that the aurora current heats the upper atmosphere.
Scientists say Cassini gives them a more detailed picture of Saturn’s upper atmosphere. The study was published in the journal Nature Astronomy.