Astronomers have made a groundbreaking discovery about Jupiter’s upper atmosphere using the NASA/ESA/CSA James Webb Space Telescope. Previously considered a dull region, the area above Jupiter’s iconic Great Red Spot has now been shown to contain a wealth of previously unseen features and dynamic structures.
Jupiter, one of the most brilliant objects in the night sky, is typically visible even to the naked eye. While the planet’s polar regions display stunning auroras, its upper atmosphere has remained elusive to ground-based telescopes due to its faint glow. Webb’s advanced infrared capabilities have now allowed scientists to peer into Jupiter’s upper atmosphere with unprecedented clarity.
Jupiter’s Upper Atmosphere: A Complex Interface
Jupiter’s upper atmosphere acts as a crucial boundary between the planet’s magnetic field and its underlying atmosphere. This region is known for its dazzling northern and southern lights, driven by volcanic material from Jupiter’s moon Io. However, scientists previously assumed that the upper atmosphere near the equator would be relatively uniform, given that Jupiter receives only 4% of the sunlight Earth does.
In July 2022, Webb’s Near-Infrared Spectrograph (NIRSpec) conducted observations of Jupiter’s upper atmosphere above the Great Red Spot. The findings were far from expected. Contrary to predictions of a monotonous region, the data revealed a complex array of dark arcs, bright spots, and intricate structures across the field of view.
Henrik Melin, team leader from the University of Leicester, UK, expressed surprise at the findings: “We initially thought this region might be rather unremarkable. It turns out, it’s as fascinating as the northern lights, if not more so. Jupiter continues to astound us.”
Uncovering the Mechanisms Behind Jupiter’s Upper Atmosphere
The light emitted from Jupiter’s upper atmosphere is influenced by sunlight, but researchers suspect additional factors are at play. Henrik Melin suggests that gravity waves, akin to ocean waves creating ripples on a beach, could be altering the structure and appearance of this atmospheric layer. Generated deep within the turbulent lower atmosphere around the Great Red Spot, these waves can ascend and impact the upper atmosphere’s characteristics.
While similar waves are observed on Earth, those seen on Jupiter by Webb are far more pronounced. The team plans to conduct further Webb observations to analyze these wave patterns, enhance our understanding of the energy dynamics in Jupiter’s upper atmosphere, and monitor how these features evolve over time.
Future Missions and Ongoing Research
These revelations from the James Webb Space Telescope may also complement findings from the European Space Agency’s Jupiter Icy Moons Explorer (JUICE), launched on April 14, 2023. JUICE aims to conduct detailed studies of Jupiter and its major moons—Ganymede, Callisto, and Europa—using an array of remote sensing and in situ instruments. This mission will provide deeper insights into Jupiter’s environment and its potential for hosting life.
The observations discussed were part of the Early Release Science programme #1373, designed to showcase JWST’s capabilities for solar system science (Co-PIs: I. de Pater, T. Fouchet). Imke de Pater from the University of California, Berkeley, noted, “Our 2017 proposal aimed to explore why the temperature above the Great Red Spot seemed unusually high. Our new data, however, revealed an entirely different picture.”
About the James Webb Space Telescope
The James Webb Space Telescope is the largest and most powerful space telescope ever launched. ESA contributed to the mission by providing the launch service with the Ariane 5 rocket and developing key instruments like the NIRSpec spectrograph and half of the mid-infrared instrument MIRI, in collaboration with international partners including JPL and the University of Arizona.