A heat wave is sweeping through Jupiter’s northern hemisphere , with temperatures up to 700°C and about 130,000 kilometers across, more than 10 times the diameter of Earth. This wave, however, has nothing to do with the heat waves that we live on Earth , which have left us one of the hottest summers in memory this 2022 and that will be enhanced by global warming that we suffer This heat wave that has been observed on Jupiter and that has been presented during the Europlanet Science Congress held in Granada, comes from the North Pole and heads towards the planet’s equator at thousands of kilometers per hour.
Heat waves on Earth usually move in the opposite direction. The hot air from the equator or the tropical regions is directed towards colder latitudes , bringing unusual temperatures for the region it affects. But this does not happen on Jupiter, because the atmosphere of the gas giant has a different dynamic. Jupiter is hotter than it should be , at least considering its distance from the Sun and the fact that it receives 4% of the solar radiation that our planet receives. This extra heat does not come from the star, but from the interior of the planet and residual heat lingering from the creation of Jupiter during the first few million years of the solar system’s life. As so much mass builds up on a planet, first collisions and then tremendous pressures have caused Jupiter’s core to reach temperatures of tens of thousands of degrees . This heat has tried to dissipate and reach the surface in the form of infrared radiation, but the slowness of this process has meant that most of this heat is still preserved today. This means that Jupiter is several degrees above its predicted temperature and temperatures of up to 400 ºC are sometimes recorded in the upper layers of its atmosphere.
This heat wave has been generated at the north pole of the gas giant after a particularly intense aurora borealis. The Earth is not the only planet that shows this type of phenomenon and in fact auroras of some kind have been observed on all the planets of the solar system except Mercury and even on the moons Io, Europa and Ganymede. of Jupiter. But not all auroras are the same, of course. While on Earth they are an occasional phenomenon and depend largely on solar activity, on Jupiter auroras are permanent , although they do suffer some variation in intensity. This is for two reasons, the first is that Jupiter’s magnetic field is much larger and more intense than Earth’s, so that although it receives fewer charged particles from the solar wind, it can collect them from a volume hundreds of times greater and accelerate them at higher energies.
In fact, Jupiter’s magnetosphere is one of the largest structures in the solar system , its tail stretching as far as the orbit of Saturn, hundreds of millions of miles away. On the other hand, Jupiter’s auroras are not only caused by the solar wind, but also by particles ejected by its moon Io . This moon is constantly being squeezed and stretched by the gravity of both the planet and the other major satellites that orbit close to Io, so that its interior is constantly being deformed.
All this activity causes a lot of friction, which heats the interior of the moon, giving Io very intense volcanic activity. This activity is responsible for large amounts of gases and particles being emitted into Jupiter’s environment, which end up being captured and accelerated by its magnetic field , taking them to the poles and creating these permanent and intense auroras.
The intensity is such that it has been repeatedly observed how the auroras heat the air of the polar regions up to 700 ºC . It is also believed that this contributes to the fact that we discussed earlier that Jupiter is hotter than it should be. Heat generated by auroras keeps the gas giant’s upper atmosphere warm, adding to the effect of residual heat generated during its formation. What had never been observed before was that a large mass of this hot air from the polar regions headed towards the equator , traveling at thousands of kilometers per hour, forming a heat wave. This is believed to have been caused by an episode of particularly intense solar activity . The tongue of hot air that descends from the north pole to the equator has a length of about 130,000 kilometers and a variable thickness of several thousand kilometers, covering a size equivalent to ten times the planet Earth.
References:
O’Donoghue, J. et al, 2022, A planetary-scale heat wave in Jupiter’s mid-latitude upper atmosphere, Europlanet Science Congress 2022 , EPSC2022-373, https://doi.org/10.5194/epsc2022-373, 2022
