The discovery of a “heat wave” on a planetary scale in Gope

Image: Panoramic view of Jupiter’s upper atmospheric temperatures, 1,000 km above the cloud tops. Jupiter appears above the visible image of the context. In this shot, the auroral region (near the North Pole, in yellow/white) appears to have cast a massive planetary-scale heating wave toward the equator. This feature is more than 130,000 kilometers long, or 10 diameters from Earth, and is hundreds of degrees warmer than the background. For the video see:
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Credit: Hubble/NASA/ESA/A. Simon (NASA GSFC)/J. Schmidt. Credit: James O’Donoghue

An unexpected “heat wave” of 700 ° C, stretching 130,000 km (10 Earth diameters) was detected in the atmosphere of Jupiter. James O’Donoghue, of the Japan Aerospace Exploration Agency (JAXA), presented the findings this week at the Europlanet Science Conference (EPSC) 2022 in Granada.

Jupiter’s atmosphere, famous for its distinctive multicolored swirls, is also unexpectedly hot: in fact, it’s hundreds of degrees warmer than models predict. Due to its orbital distance of millions of kilometers from the Sun, the giant planet receives less than 4% of the amount of sunlight compared to Earth, and its upper atmosphere should theoretically be as cold as -70 degrees Celsius. Instead, its cloud tops are everywhere measured at more than 400 degrees Celsius.

“Last year we produced – and presented at EPSC2021 – the first maps of Jupiter’s upper atmosphere capable of identifying prevalent heat sources,” said Dr. O’Donoghue. “Thanks to these maps, we showed that Jupiter’s aurora borealis was a potential mechanism that could explain these temperatures.”

Just like Earth, Jupiter experiences auroras around its poles as an effect of the solar wind. However, while the auroras on Earth are transient and only occur when solar activity is intense, the auroras on Jupiter are permanent and with variable intensity. Strong auroras can heat the region around the poles to more than 700 degrees Celsius, and global winds can redistribute heat globally around Jupiter.

Looking more deeply into their data, Dr. O’Donoghue and his team detected the incredible “heat wave” just below the Northern Lights, and found that it was moving toward the equator at thousands of kilometers per hour.

The heat wave was likely caused by a pulse of enhanced solar wind plasma affecting Jupiter’s magnetic field, which enhanced auroral heating and forced hot gases to expand and spill toward the equator.

“While the aurora borealis constantly transmits heat to the rest of the planet, these heat wave events represent an important additional source of energy,” added Dr. O’Donoghue. “These findings add to our knowledge of Jupiter’s upper atmosphere weather and climate, and are a huge help in trying to solve the ‘energy crisis’ problem that has plagued research on giant planets.”

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