Lightning storms on Jupiter follow a pattern similar to those on Earth

Data from the Juno probe show that Jupiter’s lightning is staggered in the same pattern as terrestrial thunderstorms, despite the difference between the two planets.

Data from the Juno probe show that Jupiter’s lightning is staggered in the same pattern as terrestrial thunderstorms, despite the difference between the two planets.

As different as the other worlds are, if there is water vapor and convection processes, their electrical storms will resemble ours. This is one of the conclusions that can be drawn from the work published this Tuesday by Ivana Kolmašová and her team, from the Institute of Atmospheric Sciences in Prague, in the journal Nature Communications.

The Czech researcher, who had already found similarities between the storms on Jupiter and those on Earth in a 2018 study, has analyzed high-resolution data obtained over five years by the radio receiver of the Juno space probe, located in a polar orbit around the giant planet. And what you’ve seen this time is that the radio pulses produced by lightning discharges on Jupiter occur with time separations of about a millisecond, suggesting staggered lightning initiation characteristics similar to those observed in thunderstorms on Earth.

In other words, the way lightning strikes on Jupiter may be comparable to the way lightning strikes within clouds in Earth’s atmosphere. “We have analyzed the properties of the electromagnetic pulses recorded over five years and have compared them with the characteristics of the repetitive signals emitted by terrestrial lightning”, explains Kolmašová to “And we have found strong evidence that the process of discharge evolution could be very similar in the atmospheres of both planets.”

Specifically, the authors highlight the similarity of the intervals of the repetitive radio wave signals of Jovian rays with those of Earth. “Submillisecond-resolution measurements allow us to suggest that passages of similar lengths occur in Jovian thunderclouds after lightning initiation, as is routinely observed during intercloud lightning initiation processes on Earth,” Kolmašová say.

Francisco Gordillo, an IAA-CSIC researcher specializing in electrical activity in planetary atmospheres, believes that this is a very interesting result because it provides evidence that Jupiter’s rays propagate through paths, as is the case here. To understand it, he proposes to imagine the ionization process of the atmosphere as if the plasma filaments were drops of water on a glass. “Many times it happens that a trickle of water falls from above because several come together,” he says. “When one drop meets another, it takes a ‘step’ and from there a random path is produced”, which would be the final discharge.

“Most importantly, the article provides new information about the mechanisms that can generate lightning on Jupiter, showing that it is similar to that on Earth,” adds Peio Inurrigarro, a member of the Imperial College of Space and Atmospheric Physics research team. London who has studied Jupiter’s atmosphere in detail. For Alejandro Luque, a researcher from the IAA’s Plasmas in Planetary Atmospheres (TRAPPA) group, one of the most relevant conclusions is “that the processes are not exclusive to the gaseous composition of the Earth, and that not only oxygen and nitrogen are needed” to produce them.

In Luque’s opinion, this similarity was to some extent to be expected because storms occur at similar pressures, even though Jupiter is completely gaseous and has such a different composition. “In the area where these storms occur, water clouds form, just like those on Earth, so you would expect there to be quite a few similarities,” he says.

Many of the space missions that have visited Jupiter have detected the presence of lightning on the planet, Inurrigarro stresses, referring to the lesser definition data previously collected by the Voyager 1 and 2, Galileo and Cassini probes. “Even so, little is known about the possible mechanisms that generate them and traditionally it has always been assumed that the mechanism that operates on Jupiter may be similar to that on Earth, requiring the presence of water in solid and liquid states.”

For Gordillo, the key is that the physics of clouds is the same throughout the universe and similar conditions are met, even if it is in an atmosphere rich in hydrogen and helium. “It is true that the atmosphere of Jupiter is very different from the one we have in our world; what happens is that on Jupiter we have clouds of water vapor and crystals form, so the clouds are electrically charged just like here.” The difference, in addition to the size of the rays, which in Jupiter are kilometers long, is that in the gas giant there is no ground, although the area where the pressure of 1 bar (one atmosphere) is taken as a reference, so that the rays only They occur between clouds.

As for the origin of storms, in both cases it is heat, although on our planet it is due to the influence of the sun and on Jupiter due to internal heat. “That is why most of the storms on Earth occur in tropical areas and Jupiter in polar areas,” says the specialist. This is part of what had already been seen in a first analysis of the Juno data, in which low-frequency radio emissions (so-called rapid whistlers) generated by lightning were also studied. on Jupiter that showed a similar rate of ‘firing’ to those seen in thunderstorms on Earth.

“En nuestro estudio anterior vimos señales relacionadas con rayos que no se conocían antes y que diferían sustancialmente de los registrados en 1979 por la nave espacial Voyager 1”, detalla Kolmašová. “Encontramos que las tasas de rayos en Júpiter son muy parecidas a las observadas en la Tierra, pero la distribución de los relámpagos en Júpiter difieren, porque la mayoría de los relámpagos jovianos ocurren en latitudes medias y también en regiones polares”. 

This meant that the conditions for a thundercloud formation on Jupiter and Earth were probably very different, but this new result shows us again the points where they are similar, which partly explains why when we see the flash sequences on Jupiter’s atmosphere reminds us so much of the storms that astronauts see when they fly over the Earth. “Its luminosity has been photographed many times from the outside,” says Gordillo. “They are small luminous dots in the night of Jupiter; it was seen that they are more powerful, and of the order of 100 times more energetic”.