Planetary-scale ‘heat wave’ discovered in Jupiter’s atmosphere

Jupiter’s atmosphere contains an unexpected “heat wave” that is 700 degrees Celsius and spans 130,000 kilometres (10 Earth diameters). The findings were presented this week at the Europlanet Science Congress (EPSC) 2022 in Granada by James O’Donoghue of the Japanese Aerospace Exploration Agency (JAXA).

The atmosphere of Jupiter, known for its distinctive multicoloured vortices, is also surprisingly warm; in fact, it is hundreds of degrees warmer than expected. The giant planet receives only 4% as much sunlight as Earth does due to its orbital distance of millions of kilometres, and its upper atmosphere should be a chilly -70 degrees Celsius. Instead, everywhere it is measured, its cloud tops are over 400 degrees Celsius. The first maps of Jupiter’s upper atmosphere that could pinpoint the main sources of heat were created and presented at EPSC2021 last year, according to Dr O’Donoghue. We were able to show that Jupiter’s auroras could potentially account for these temperatures using these maps.

Jupiter experiences auroras around its poles as a result of the solar wind, just like the Earth does. However, Jupiter’s auroras are permanent and vary in intensity, in contrast to Earth’s auroras, which are transient and only manifest when solar activity is high. Strong auroras have been known to heat the area around the poles to over 700 degrees Celsius, and global winds have been known to redistribute heat across the entire area around Jupiter. Dr O’Donoghue and his team discovered the stunning “heat wave” just beneath the northern aurora by digging deeper into their data, and they discovered that it was moving towards the equator at a speed of thousands of kilometres per hour.

The enhanced solar wind plasma pulse that struck Jupiter’s magnetic field and increased auroral heating likely caused the heat wave by forcing hot gases to expand and spill out towards the equator. Dr O’Donoghue continued, “These heat wave ‘events’ represent an additional, significant energy source, while the auroras continuously deliver heat to the rest of the planet. These discoveries advance our understanding of Jupiter’s upper-atmosphere weather and climate and greatly aid efforts to address the “energy crisis” that impedes the study of the giant planets. 1000 km above the cloud tops, a panning view of Jupiter’s upper atmospheric temperatures. For context, Jupiter is displayed on top of a visible picture. An enormous, planetary-scale wave of heating appears to have been shed by the auroral region (near the northern pole, in yellow/white) toward the equator in this image. The feature is ten Earth diameters long and over 130,000 kilometres wide. It is also hundreds of degrees warmer than the surrounding area. The image of the visible Jupiter was taken by Hubble, NASA, ESA, A. Simon (NASA GSFC), and J. Schmidt. James O’Donoghue is to blame.