While Jupiter’s Great Red Spot is one of the most well-known spectacles in the Solar System, Jupiter’s clouds and stripes, which are responsible for the planet’s weather patterns, are also highly regarded. Though not nearly as visible in an amateur astronomy telescope, Jupiter’s colorful, rotating, and swirling cloud streaks are a sight to behold up close for any astronomy buff. And what makes these stripes unique is that they have been observed to change color from time to time, but the question of what causes this color change has not yet been resolved.
This is the aim of a study recently published in Nature Astronomy. An international team of researchers is studying how Jupiter’s massive magnetic field could be responsible for Jupiter’s changing stripe colors. This study was conducted by Dr. Kumiko Hori from Kobe University and Dr. Chris Jones of the University of Leeds and has the potential to help scientists better understand how a planet’s magnetic field might affect a planet’s weather patterns. In this case, Jupiter’s massive magnetic field affects its massive, swirling clouds.
“If you look at Jupiter through a telescope, you see the streaks that run along the lines of latitude around the equator,” explains Dr. Jones. “There are dark belts and light belts, and if you look a little closer you can see clouds carried by exceptionally strong east and west winds. Near the equator, the wind blows east, but if you change the latitude a bit, either north or south, it turns west. And if you then go a little further away, it goes east again. This alternating pattern of east and west winds is very different from weather on Earth.”
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While previous studies have shown that Jupiter’s appearance is somehow altered by infrared fluctuations about 50 km (31 miles) below the gas cloud surface, this most recent study shows that the infrared fluctuations could be caused by Jupiter’s magnetic field, the source of which, like Earth, lies much deeper inside the planet.
“Every four or five years things change,” said Dr. Jones. “The colors of the belts can change and sometimes global upheaval occurs when the overall weather pattern goes slightly crazy for a while, and it’s been a mystery as to why that’s happening.”
Infrared images of Jupiter taken with a ground-based telescope showing changes in the color of Jupiter’s clouds between 2001 and 2011 (dashed blue lines). (Source: Arrate Antuñano/NASA/IRTF/NSFCam/SpeX)
For the study, the researchers analyzed data collected over several years by NASA’s Juno spacecraft to both observe and measure variations in Jupiter’s magnetic field, better known as oscillations. Despite Jupiter’s massive radiation belt, capable of inflicting tremendous damage on any spacecraft, Juno has been orbiting the solar system’s largest planet since 2016, and is widely praised for remaining active despite the constant bombardment of radiation.
Using the data, the team was able to monitor the waves and oscillations of the magnetic field. They focused on a specific area of the magnetic field, called the Great Blue Spot, invisible to the naked eye and located near Jupiter’s equator. Although this point on Jupiter has been observed moving eastward, the data in this study suggests the point is slowing down, which the team interprets as the beginning of an oscillation within the magnetic field, meaning the point will eventually move slow enough to get where he is, reverse direction and start traveling west.
Still from a video animation showing Jupiter’s massive magnetic field at one point in time, specifically its Great Blue Spot near Jupiter’s equator, which is invisible to the naked eye and was a focus of this study. (Source: NASA/JPL-Caltech/Harvard/Moore et al.)
The study’s results suggest that these oscillations could explain the changes in Jupiter’s stripes and bands over time, but the study doesn’t assume that’s the ultimate reason.
“Uncertainties and questions remain, particularly how exactly the torsional vibration produces the observed infrared variation, which likely reflects the complex dynamics and cloud/aerosol responses,” said Dr. Hori, who conducted the research while studying at the University of Leeds and is the lead author on the study. “These need more research. Still, I hope that our work could also open a window into exploring the hidden deep interior of Jupiter, as seismology does for Earth and helioseismology for the Sun.”
NASA’s Juno spacecraft
NASA’s Juno spacecraft was launched in 2011 and reached Jupiter five years later. It has returned some of the most stunning close-up images of Jupiter ever taken, along with occasional images of Jupiter’s Galilean moons due to the spacecraft’s extended orbit around Jupiter. This latest study demonstrates Juno’s continued commitment to conducting new scientific discoveries that teach researchers something new about Jupiter and its harsh environment.
Artist’s rendering of Jupiter and NASA’s Juno spacecraft. (Source: NASA/JPL-Caltech)
Juno is now in its seventh year of scientific operations around Jupiter and is scheduled to explore the solar system’s largest planet until September 2025, or until Juno’s end of life.
What discoveries about Jupiter and its massive magnetic field will Juno teach us over the next few years? Only time will tell, and that’s why we do science!
As always, keep up the science and keep looking up!