Researchers have solved the mystery of lightning on Jupiter

James Marshall
June 9, 2018

Among other things, researchers from the Czech Academy of Sciences also found that lightning on the planet occurs just as frequently on Earth - another similarity.

On Earth, radio waves associated with lightning are in the megahertz range.

If it had achieved its intended 14-day orbit, Juno would have had time to carry out all of its primary science experiments, but the 53-day orbit at a distance of between 3,000 mi (5,000 km) and five million mi (eight million km) of the cloud tops meant that it spends much more time in the outer Jovian system than planned, and subsequently has less time for observations. But this time, according to Shannon Brown, a lead author on the paper, these lightning strikes were able to be recorded in the megahertz range, which is the same we use to measure the radio waves from the lightning experienced on Earth.

"Our microwave and plasma wave instruments are state-of-the-art, allowing us to pick out even weak lightning signals from the cacophony of radio emissions from Jupiter". An analysis of radio signals received by the unmanned deep space probe suggest that Jupiter's lighting storms are very similar to those on Earth, but are inside out compared to ours. The origin of Jupiter's lightning is one such mystery it has focused on, ever since its Voyager 1 spacecraft flew past Jupiter in March 1979. The majority of Jupiter's zaps take place near the poles.

"Many theories were offered up to explain it, but no one theory could ever get traction as the answer", Brown said of the problem. As Choi reports, scientists have speculated many reasons behind the difference, including variations in the atmosphere or even fundamental distinctions between how lightning forms. On Earth, lightning bolts congregate near the equator, but in the Jovian environment, the same happens closer to the poles, more so in the northern hemisphere.

In a pair of studies published on June 6, scientists from the Juno mission describe the radio emissions coming from Jovian lightning - dubbed "whistlers" on account of their descending whistling pitch, which sounds a lot like a falling bomb - as well as the novel frequencies at which they were picked up by the spacecraft still in orbit around the gas giant. The sunlight that does reach Jupiter heats up the equatorial region, leading to an area of atmospheric stability that prevents warm air from rising.

Enter Juno, which has been orbiting Jupiter since July 4, 2016.

Still, we must keep in mind that a significant difference between Earth's lightning and Jupiter's remains.

But there's one more way lightning on Jupiter is similar to Earth lightning.

Heat drives lightning, and the sun's rays cause Earth's equator to heat up more than the poles.

"As we complete the remainder of the orbits in the mission, we'll get a clearer and clearer picture of the distribution of lightning, which maps out moist convective activity on the planet".

"These findings could help to improve our understanding of the composition, circulation and energy flows on Jupiter". NASA just re-enlisted Juno, adding another 41 months to its mission.

Juno has made all of this research possible.

"This is great news for planetary exploration as well as for the Juno team", said Scott Bolton, principal investigator of Juno, from the Southwest Research Institute in San Antonio.

Other reports by Click Lancashire

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