"They were recorded in the megahertz as well as gigahertz range [of the radio spectrum], which is what you can find with terrestrial lightning emissions", Brown added.
"Also, 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".
Since then, NASA's Galileo and Cassini, which whizzed near Jupiter on its way to Saturn, validated the initial theories that lightning on Jupiter occurs.
"Jupiter lightning distribution is inside out relative to Earth", said said Shannon Brown, lead author of the paper and a Juno scientist.
"Lightning on Jupiter can be as frequent as on Earth", stated Ivana Kolmasova from the Czech Academy of Sciences and the leading author of one of the recent studies.
Ever since the space agency's Voyager spacecraft whizzed past the gas giant, scientists have noted evidence of lightning on Jupiter. This, in spite of Jupiter's equator playing host to the solar system's largest, most ferocious storm. Many theories tried to explain the phenomenon, but none of them could ever visualize traction as the answer.
An artist's impression of lightning bolts in the atmosphere if Jupiter.
Just like in the famous GIF, Juno uncovered that lightning on Jupiter is very much the same as on Earth, while also being completely different.
That's a lot to digest, so let's break it down a bit: All the tools on previous spacecraft that tried to listen in to Jupiter's lightning didn't hear the kinds of radio signals that are produced by lightning on Earth. The spacecraft came nearly 50 times closer to the planet than Voyager 1 ever did, flying "closer to Jupiter than any other spacecraft in history", states Juno's principal investigator Scott Bolton from the Southwest Research Institute in San Antonio, who was involved in both studies.
Above all these, the most surprising discovery was that the Jupiter lightning storms are pretty much the same with the thunderstorms we can observe on Earth. Because our equator bears the brunt of this sunshine, warm moist air rises (through convection) more freely there, which fuels towering thunderstorms that produce lightning. The gas giant is much farther from the Sun and its poles aren't getting warmed, therefore having a less stable atmosphere. Nasa has put in one of its highly sensitive instruments called Microwave Radiometer Instrument (MWR), which records gas emissions from Juno, spanning a wide range of frequencies. Heat rising from the planet creates roiling convection currents that lead to storms and lightning.
Brown said these findings could help scientists' understand how energy flows on Jupiter. This rate and amount is six times more lightning than Voyager observed. After two years of orbit, Juno remained operationally healthy, extending its mission to another three years.
Juno will make the 13th flyby out of 37 planned orbits over Jupiter's mysterous cloud tops on 16 July.
"These updated plans for Juno will allow it to complete its primary science goals", said Juno principal investigator Scott Bolton.