An unexpected 700 degrees Celsius ‘heat wave’ has been discovered extending 130,000 kilometers (10 Earth diameters) into Jupiter’s atmosphere. James O’Donoghue, of Japan’s Aerospace Exploration Agency (JAXA), presented the results this week at the Europlanet Science Congress (EPSC) 2022 in Granada.
Jupiter’s atmosphere, famous for its characteristic multicolored vortices, is also unexpectedly hot: in fact, it’s hundreds of degrees hotter than models predict. Due to its orbital distance of millions of kilometers from the sun, the giant planet receives less than 4% the amount of sunlight compared to Earth, and its upper atmosphere should theoretically be a frigid -70 degrees Celsius. Instead, cloud tops everywhere are measured at over 400 degrees Celsius.
“Last year we produced the first maps of Jupiter’s upper atmosphere — and presented them at EPSC2021 — capable of identifying the dominant heat sources,” said Dr O’Donoghue. “Thanks to these maps, we showed that Jupiter’s auroras were a possible mechanism that could explain these temperatures.”
Like Earth, Jupiter experiences auroras around its poles as an effect of the solar wind. Although Earth’s auroras are transient and occur only when solar activity is intense, Jupiter’s auroras are permanent and of variable intensity. The powerful auroras could heat the area around the poles to over 700 degrees Celsius, and global winds could redistribute heat around Jupiter worldwide.
dr. Looking deeper into their data, O’Donoghue and his team discovered the spectacular “heat wave” just below the northern aurora and found that it was traveling toward the equator at thousands of miles per hour.
The heat wave was likely caused by a pulse of amplified solar wind plasma hitting Jupiter’s magnetic field, increasing the warming of the aurora and forcing hot gases to expand and flow toward the equator.
“While the auroras continuously provide heat to the rest of the planet, these heat wave ‘events’ provide an additional, significant source of energy,” added Dr O’Donoghue. “These findings add to our knowledge of the weather and climate in Jupiter’s upper atmosphere, and are of great help in solving the ‘energy crisis’ problem that plagues research on the giant planets.”
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