A team of scientists has finally found the reason behind the extreme heat, especially in Jupiter's upper atmosphere. After decades of research, scientists have revealed that Jupiter’s version of Earth’s northern and southern lights is the cause of the increased temperature.
According to the scientists, the temperature of Jupiter should be about –73°C as it orbits at an average distance of 778 million kilometres from the Sun. However, an area several hundred kilometres above the planet’s cloud tops has an average temperature of about 426°C.
Interestingly, scientists first noticed this difference in temperature over 40 years ago. Since then, numerous researchers have come up with various ideas about where the upper atmosphere’s thermal boost might originate from, including pressure waves or gravity waves created by turbulence lower in the atmosphere.
The team of scientists led by James O’Donoghue, a planetary scientist at the JAXA Institute of Space and Astronautical Science in Sagamihara, Japan, has provided convincing data that the auroras pump heat throughout the planet’s upper atmosphere.
The team used the 10-metre Keck II telescope atop Hawaii’s dormant Mauna Kea volcano to observe Jupiter on one night each in 2016 and 2017. To calculate more precisely, the team looked for infrared emissions that betray the presence of positively charged hydrogen molecules (H3+). While measuring the intensities of these molecules’ infrared emissions, the team was able to detect how hot it gets high above the cloud tops.
"It was pure luck that we captured this potential heat-shedding event", O’Donoghue said. The team will now be working to understand the underlying mechanisms of heat production and heat transfer in the planet's atmosphere and later incorporate the findings into Jupiter’s atmospheric circulation simulations.