Jupiter’s alternating bands of dark and light clouds have mystified scientists for years. However, a team of scientists from Japan, Spain, and the UK now think they have figured out the reason for the cyclic variations in Jupiter’s stripes. After studying data on Jupiter’s magnetic field collected by the Juno probe, the team suggests that the changes seen in Jupiter’s stripes coincide with magnetic oscillations inside the gas world.
The Stripes on Jupiter
Jupiter appears serene from a distance with alternating bands of dark and light clouds. These darker stripes are known as belts, while the paler ones are known as zones. The belts and zones are part of Jupiter’s wild weather system. They circle the giant planet in opposite directions, and at different altitudes. The belts are regions of upwelling, so the cloud tops in the belts are higher than the cloud tops in the downwelling zones. In infrared, the color scheme reverses, with the light bands becoming dark and the dark bands shining brightly, suggesting that the belts have a much thinner cloud covering than the zones.
Mystery Solved
Juno has been studying Jupiter since 2016, collecting data on Jupiter’s various structures and properties. One of those is the planet’s magnetic field, generated by Jupiter’s dynamo, a convecting and conducting fluid rotating in the planetary interior that converts kinetic energy into magnetic energy. By studying years’ worth of magnetic field data collected by Juno, the team was able to identify the signatures of magnetic torsional oscillations in Jupiter, similar to Earth’s dynamo.
The team suggests that torsional oscillations give rise to a shear that disrupts the slow convective flows in the deep interior that carry the heat flux towards the visible troposphere. This could cause a major disruption to the weather and alter the patterns of upwelling and downwelling in the Jovian clouds. The team also tracked a highly concentrated region of the magnetic field called the Great Blue Spot near the equator, finding that it is slowing down, suggesting that a new oscillation is beginning.
The Mystery of Jupiter’s Weather
Every four or five years, Jupiter’s weather pattern changes. The colors of the belts can change, and sometimes, global upheavals occur. Jupiter’s weather is so vastly different from that on Earth that it’s impossible to extrapolate what one planet does onto the other. Jupiter’s cyclic variations in its clouds have left scientists puzzled, but this new discovery could help solve the mystery.
While there remain uncertainties and questions, particularly how exactly the torsional oscillation produces the observed infrared variation, which likely reflects the complex dynamics and cloud/aerosol reactions, more research is needed. Nonetheless, the team’s paper could open a window to probe the hidden deep interior of Jupiter, similar to how seismology does for the Earth and helioseismology does for the Sun. Continuing to observe the planet and how the clouds change in the near future could help validate or refine the team’s theory and understand how it happens.
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