Today’s Jupiter, the largest planet in our solar system, is predictably unusual: Mushballs with a side of shallow lightning.
In a paper published last week in the journal Nature, and two more in the Journal of Geophysical Research: Planets, scientists share new insights into Jupiter’s weather phenomenon based on observations made by NASA’s Juno spacecraft currently orbiting the planet. The analyzes suggest a forecast that is markedly alienated by Earth standards, as powerful lightning strikes and other global slugs regularly fur the gas giant.
The scientists hope that by understanding the atmospheric dynamics of Jupiter and its meteorology, they can better understand the atmospheric dynamics of other planets in our solar system, such as ecopoplanets at a distance. (Some exotic exoplanets are thought to have even warmer weather, including one where it may rain sunny weather.)
“Juno’s narrow flybys of the cloud tops showed us something surprising – smaller, shallow flashes – emerging at much higher altitudes in Jupiter’s atmosphere than previously thought possible,” said Heidi Becker of NASA’s Jet Propulsion Laboratory and lead author. of the Nature paper, said in a statement.
In 1979, NASA’s Voyager mission first discovered that there was lightning on Jupiter, prompting speculation that conditions in Jupiter’s atmosphere may be similar to Earth. Specifically, clouds made of water could make Jovian thunderbolts, just as they do here.
However, the pressures and temperatures that would create water ice (meaning ice made from normal H2O) and clouds may only occur on Jupiter about 28 to 40 miles below the visible clouds. This does not go with the evidence: observations of the dark side of Jupiter by Juno found that there were electric storms at much higher altitudes than that.
So what was the making of the lightning, if not clouds with water ice?
Based on the new observations, Becker and her team say that thunderstorms on Jupiter “throw” ice crystals “about 16 miles above the water clouds. In this higher, colder region of Jupiter’s atmosphere, these water-ice crystals collide with ammonia vapor, which melts the ice. This provides a new solution of ammonia-water, which generates these high-altitude electric storms that Juno observed.
“At these altitudes, the ammonia acts as an antifreeze, lowering the melting point of water ice and allowing the formation of a cloud with ammonia-water liquid,” Becker said. “In this new state, falling droplets of ammonia-water liquid can collide with the rising crystals of water-ice and electrify the clouds.”
In other words, a collision between rising water ice crystals and falling ammonia water levels causes the shallow lightning scientists to observe.
According to the NASA release, the shallow lightning solves another puzzle regarding the amount of ammonia in the gas giant’s atmosphere. In Juno’s observations, ammonia was not observed in most of Jupiter’s atmosphere. It turns out it was there – but just not at the edge of the atmosphere where Juno’s instruments could look good.
“Earlier, scientists realized that there were small pockets of missing ammonia, but no one realized how deep these pockets went or that they covered most of Jupiter,” said Scott Bolton, Juno’s lead researcher at the Southwest Research Institute in San Antonio, in ‘ a NASA statement. “We have difficulty explaining only the ammonia depletion with ammonia-water rain, but the rain could not go deep enough to match the observations.”
Bolton said the shallow lightning discovery gave scientists the evidence they needed to know that the ammonia “mixes with water high in the atmosphere, and thus the lightning was a key piece of the puzzle.”
NASA posted a video visualization on YouTube (complete with a dramatic soundtrack by Greek composer Vangelis).
The mouse balls are a very different ball game on Jupiter, but they are also made of ammonia. According to the paper in the Journal of Geophysical Research: Planets, a combination of two-thirds water and one-third ammonia gas is perfect for Jovian hailstones, also known as “mushrooms.” These mushrooms are basically water-ammonia slush, and they are made in a similar way that is hail on Earth. As they move the atmosphere up and down, they become larger.
“Eventually the mushrooms become so large, even the updrafts can not hold them, and they fall deeper into the atmosphere, encountering even warmer temperatures, where they eventually completely evaporate,” said Tristan Guillot, a co-researcher of Juno’s. the Université Côte d’Azur in Nice, France, and lead author of the second paper, said in the release. “Their action drags ammonia and water to deep levels in the planet’s atmosphere.”
In other words, the ammonia is deeper in the atmosphere, beyond what could be seen by Juno’s microwave radiometer. That explains the “lack” of ammonia.
“This was a big surprise because ammonia-water clouds do not exist on Earth,” Guillot said.
