Image: Artist’s impression of Jupiter showing temperature differences in the upper atmosphere. The hottest parts (around the poles) are colored white and yellow, and the coldest parts are dark red. (J.O’Donoghue (JAXA) / Hubble/NASA/ESA/A.Simon/J.Schmidt)
Since you’re five times farther from the sun than Earth, you’d expect Jupiter to not be particularly warm. Depending on the amount of sunlight Jupiter receives, the temperature at the top of its atmosphere should be around -73°C. But instead it is 500 degrees warmer. Researchers now believe they have one for this dilemma, as science struggled for nearly another fifty years.
To investigate, Jupiter was recently observed with NASA’s Juno spacecraft, the Keck Observatory in Hawaii, and the Japanese satellite Hisaki. The data collected, including a detailed heat map of the giant planet’s high atmosphere, shows that Jupiter’s aurora borealis are responsible for the high temperatures.
Arctic light is generated when electrically charged particles are captured by a planet’s magnetic field. These particles then coil along the invisible field lines of the magnetic field to the planet’s poles, bumping into atoms and molecules in the atmosphere along the way – a process that releases light and heat.
On Earth, this results in colorful “light shows” known as the northern and southern lights. On Jupiter, the auroras are more intense. This is caused by Jupiter’s volcanically active moon Io, which emits large numbers of charged particles that eventually end up in Jupiter. This supply of so-called ions is responsible for the strongest auroras in our solar system and for the strong warming of the atmosphere over the polar regions of the planet.
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