Observation of Jupiter’s Atmosphere Reveals New Features
The James Webb Telescope peered into the region above Jupiter’s famous Great Red Spot and discovered a series of newly observed features.
Jupiter is undoubtedly one of the most striking objects in the night sky and can easily be spotted on a clear night. Aside from the bright auroras in the planet’s polar regions, the glow from Jupiter’s upper atmosphere is faint, making it challenging to observe details with terrestrial telescopes. Fortunately, the James Webb Telescope, with its infrared sensitivity, can study Jupiter’s upper atmosphere just above the Great Red Spot with unparalleled precision.
The Upper Atmosphere of Jupiter
Jupiter’s upper atmosphere serves as the transition layer between the planet’s magnetic field and its underlying atmosphere. In this region, the bright and vibrant auroras, powered by volcanic material emitted by Jupiter’s moon Io, can be seen. Closer to the equator, this atmosphere’s structure is influenced by incoming sunlight. As Jupiter receives only 4 percent of the sunlight Earth does, astronomers thought this region would be relatively uniform.
The Great Red Spot: More Than Meets the Eye
In July 2022, the Great Red Spot of Jupiter was observed with Webb’s Near-Infrared Spectrograph (NIRSpec), utilizing the instrument’s Integral Field Unit. The aim was to determine whether the area directly above the famous storm was as dull as scientists suspected. To their surprise, they found that the upper atmosphere contains numerous complex structures, including dark arcs and bright spots, as noted in Nature Astronomy. “We perhaps naively assumed this region would be really boring,” says team leader Henrik Melin. “But it turns out it’s just as interesting as the auroras, if not more so. Jupiter never ceases to surprise us.”
Gravity Waves and Atmospheric Changes
In short, an area once thought to be unremarkable has now been revealed to host a diverse array of complicated structures and activities. While the light emission from this region is caused by sunlight, the team suggests another mechanism must be influencing the shape and structure of the upper atmosphere. “One way to change this structure is through gravity waves,” Henrik explains. “It’s similar to waves breaking on a beach and causing ripples in the sand. These waves originate deep in the turbulent lower atmosphere around the Great Red Spot and can move upwards to higher layers, leading to changes in the structure and emission of the upper atmosphere.” Such atmospheric waves can occasionally be seen on Earth, though they are much weaker compared to those observed on Jupiter by Webb.
Future Research and Missions
The team hopes future research with Webb will further investigate Jupiter’s complex wave patterns. They aim to understand how these patterns move in the planet’s upper atmosphere, gain insights into the energy balance in this region, and study how its features change over time.
Moreover, these discoveries are also significant for ESA’s Jupiter Icy Moons Explorer (Juice) mission, launched on April 14, 2023. Juice will conduct extensive observations of Jupiter and its three large oceanic moons—Ganymedes, Callisto, and Europa. The mission aims to characterize these moons while also examining Jupiter’s intricate environment in detail.
Thanks to the newfound knowledge of atmospheric processes and dynamics on Jupiter, we are gaining a clearer picture of this enigmatic planet and its moons. Hopefully, this will not only enhance our understanding of our solar system but also contribute to our knowledge of gas giants and their moons elsewhere in the universe.
