NASA’s Juno Shows Jupiter’s Environment More Extreme Than Expected

For the past couple of years, NASA’s Juno spacecraft has been diligently gathering data on Jupiter to help scientists better understand the planet’s origins. Juno’s multiple flybys have finally allowed it to peer through Jupiter’s swirling and mysterious clouds. Recently collected data from Juno has revealed Jupiter’s environment is more extreme than NASA scientists previously thought.

New data gathered by Juno has fuelled four research papers that will help improve scientists’ understanding of Jupiter’s core mass, internal structure and its origin. Three of these studies have delved into Jupiter’s gravitational field to help reveal how dynamic the planet's environment is and how far it extends. The papers also probe what lies within the planet’s interior — at the end of its extensive atmosphere. The research on Jupiter's interior can be accessed here.

“These astonishing science results are yet another example of Jupiter’s curve balls, and a testimony to the value of exploring the unknown from a new perspective with next-generation instruments. Juno’s unique orbit and evolutionary high-precision radio science and infrared technologies enabled these paradigm-shifting discoveries,” Scott Bolton, Juno’s principal investigator, said in a statement. “Juno is only about one third the way through its primary mission, and already we are seeing the beginnings of a new Jupiter.”

“Prior to Juno we did not know what the weather was like near Jupiter’s poles. Now, we have been able to observe the polar weather up-close every two months,” said Alberto Adriani, Juno co-investigator from the Institute for Space Astrophysics and Planetology, Rome, and lead author of one of the research papers on Jupiter’s poles. “Each one of the northern cyclones is almost as wide as the distance between Naples, Italy and New York City — and the southern ones are even larger than that. They have very violent winds, reaching, in some cases, speeds as great as 220 mph (350 kph). Finally, and perhaps most remarkably, they are very close together and enduring. There is nothing else like it that we know of in the solar system.”

Until now, the depth of Jupiter’s famous belts and zones were a mystery to us. However, Juno’s flybys allowed the spacecraft to collect gravity measurements, which has provided scientists with the ability to answer questions about its zones and belts.

“Juno’s measurement of Jupiter’s gravity field indicates a north-south asymmetry, similar to the asymmetry observed in its zones and belts,” said Luciano Iess, Juno co-investigator from Sapienza University of Rome, and lead author on a paper on Jupiter’s gravity field in the journal Nature.

As part of the multiple new research, Jupiter’s asymmetrical gravitational field was studied by scientists. ScienceAlert reported Juno’s polar orbit allowed it to study both the gas giant’s poles separately. This led to the discovery that a part of Jupiter’s gravitational field does not have the expected north-south symmetry.

The research paper on Jupiter’s asymmetric gravity field is available here.

“Galileo viewed the stripes on Jupiter more than 400 years ago,” said Yohai Kaspi, Juno co-investigator from the Weizmann Institute of Science, Israel, and lead author of a Nature paper on Jupiter’s deep weather layer. “Until now, we only had a superficial understanding of them and have been able to relate these stripes to cloud features along Jupiter’s jets. Now, following the Juno gravity measurements, we know how deep the jets extend and what their structure is beneath the visible clouds. It’s like going from a 2-D picture to a 3-D version in high definition.”

The study on the gas giant's atmospheric jet-streams can be found here.

Scientists were surprised by the findings of the research because it indicated Jupiter’s weather layer was “more massive, extending much deeper than previously expected.” It was also found Jupiter’s weather layer, which extends 1,900 miles (3,000 kilometers), contains about one percent of the planet’s mass.

“By contrast, Earth’s atmosphere is less than one millionth of the total mass of Earth,” said Kaspi “The fact that Jupiter has such a massive region rotating in separate east-west bands is definitely a surprise.”

Another paper based on Juno’s data suggests underneath Jupiter’s weather layer, the gas giant rotates almost as a rigid body.

“This is really an amazing result, and future measurements by Juno will help us understand how the transition works between the weather layer and the rigid body below,” said Tristan Guillot, a Juno co-investigator from the Université Côte d’Azur, France, and lead author of the paper on Jupiter’s deep interior. “Juno’s discovery has implications for other worlds in our solar system and beyond. Our results imply that the outer differentially-rotating region should be at least three times deeper in Saturn and shallower in massive giant planets and brown dwarf stars.”

Researchers also discovered despite Jupiter’s eight polar cyclones being so densely packed together that their spiral arms bump into each other, they still remain independent.

“The question is, why do they not merge? We know with Cassini data that Saturn has a single cyclonic vortex at each pole,” said Adriani. “We are beginning to realize that not all gas giants are created equal.”

The study on Jupiter's polar cluster of cyclones is available here.