New observations of Jupiter’s Great Red Spot have revealed that the planet’s atmosphere above and around the infamous storm is surprisingly interesting and active. This graphic shows the region observed by Webb—first, its position on a NIRCam image of the entire planet (left), and the region itself (right), captured by Webb’s Near-Infrared Spectrograph (NIRSpec). The NIRSpec image is a composite of six NIRSpec Integral Field Unit images taken in July 2022, each about 300 square kilometers in size, and shows infrared light emitted by hydrogen molecules in Jupiter’s ionosphere. These molecules lie over 300 km above the storm’s clouds, where sunlight ionizes the hydrogen and stimulates this infrared emission. In this image, redder colors show hydrogen emission from these high altitudes in the planet’s ionosphere. Bluer colors show infrared light from lower altitudes, including cloud tops in the atmosphere and the very prominent Great Red Spot. Jupiter is far from the Sun and therefore receives a uniform, low level of daylight, meaning that most of the planet’s surface is relatively dark at these infrared wavelengths – especially compared to emissions from molecules near the poles, where Jupiter’s magnetic field is particularly strong. Contrary to researchers’ expectations that this area would therefore look naturally homogeneous, it exhibits a variety of complex structures across the entire field of view, including dark arcs and bright patches. Image credit: ESA/Webb, NASA & CSA, Jupiter ERS Team, J. Schmidt, H. Melin, M. Zamani (ESA/Webb)
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New observations of Jupiter’s Great Red Spot have revealed that the planet’s atmosphere above and around the infamous storm is surprisingly interesting and active. This graphic shows the region observed by Webb—first, its position on a NIRCam image of the entire planet (left), and the region itself (right), captured by Webb’s Near-Infrared Spectrograph (NIRSpec). The NIRSpec image is a composite of six NIRSpec Integral Field Unit images taken in July 2022, each about 300 square kilometers in size, and shows infrared light emitted by hydrogen molecules in Jupiter’s ionosphere. These molecules lie over 300 km above the storm’s clouds, where sunlight ionizes the hydrogen and stimulates this infrared emission. In this image, redder colors show hydrogen emission from these high altitudes in the planet’s ionosphere. Bluer colors show infrared light from lower altitudes, including cloud tops in the atmosphere and the very prominent Great Red Spot. Jupiter is far from the Sun and therefore receives a uniform, low level of daylight, meaning that most of the planet’s surface is relatively dark at these infrared wavelengths – especially compared to emissions from molecules near the poles, where Jupiter’s magnetic field is particularly strong. Contrary to researchers’ expectations that this area would therefore look naturally homogeneous, it exhibits a variety of complex structures across the entire field of view, including dark arcs and bright patches. Image credit: ESA/Webb, NASA & CSA, Jupiter ERS Team, J. Schmidt, H. Melin, M. Zamani (ESA/Webb)
Using the NASA/ESA/CSA James Webb Space Telescope, scientists observed the region above Jupiter’s iconic Great Red Spot and discovered a variety of previously unknown features. The region, previously thought to be unremarkable, exhibits a variety of complex structures and activity.
Jupiter is one of the brightest objects in the night sky and is easily seen on clear nights. Aside from the bright Northern and Southern Lights in the planet’s polar regions, the glow from Jupiter’s upper atmosphere is faint, making it difficult for ground-based telescopes to see details in this region. However, the Webb telescope’s infrared sensitivity allows scientists to study Jupiter’s upper atmosphere above the infamous Great Red Spot in unprecedented detail.
Jupiter’s upper atmosphere is the interface between the planet’s magnetic field and the atmosphere below. This is where the bright and vibrant Northern and Southern Lights can be seen, fed by volcanic material ejected from Jupiter’s moon Io.
Closer to the equator, however, the structure of the planet’s upper atmosphere is influenced by incoming sunlight. Since Jupiter receives only 4% of the sunlight that Earth receives, astronomers predicted this region to be more homogeneous in nature.
Jupiter’s Great Red Spot was observed by Webb’s Near-Infrared Spectrograph (NIRSpec) in July 2022, using the instrument’s Integral Field Unit capabilities. The team’s Early Release Science observations were designed to investigate whether this region is indeed hazy, and the region above the iconic Great Red Spot was the target of Webb’s observations.
The team was surprised to discover that the upper atmosphere contains a variety of complex structures, including dark arcs and bright patches, spread across the entire field of view. The results were published in Natural astronomy.
“We thought, perhaps naively, that this region would be really boring,” said team leader Henrik Melin of the University of Leicester in the UK. “In fact, it is just as interesting as the Northern Lights, if not more so. Jupiter never ceases to amaze.”
Although the light emitted from this region is generated by sunlight, the team suspects that there must be another mechanism that changes the shape and structure of the upper atmosphere.
New observations of Jupiter’s Great Red Spot have revealed that the planet’s atmosphere above and around the infamous storm is surprisingly interesting and active. This image shows the region observed by Webb’s Near-Infrared Spectrograph (NIRSpec). It is composited from six NIRSpec Integral Field Unit images taken in July 2022, each about 300 square kilometers in size. The NIRSpec observations show infrared light emitted by hydrogen molecules in Jupiter’s ionosphere. These molecules lie over 300 km above the storm’s clouds, where sunlight ionizes the hydrogen and stimulates this infrared emission. In this image, redder colors show hydrogen emission from these high altitudes in the planet’s ionosphere. Bluer colors show infrared light from lower altitudes, including cloud tops in the atmosphere and the prominent Great Red Spot. Image credit: ESA/Webb, NASA & CSA, H. Melin, M. Zamani (ESA/Webb) CC BY 4.0 INT or ESA standard license
× close
New observations of Jupiter’s Great Red Spot have revealed that the planet’s atmosphere above and around the infamous storm is surprisingly interesting and active. This image shows the region observed by Webb’s Near-Infrared Spectrograph (NIRSpec). It is composited from six NIRSpec Integral Field Unit images taken in July 2022, each about 300 square kilometers in size. The NIRSpec observations show infrared light emitted by hydrogen molecules in Jupiter’s ionosphere. These molecules lie over 300 km above the storm’s clouds, where sunlight ionizes the hydrogen and stimulates this infrared emission. In this image, redder colors show hydrogen emission from these high altitudes in the planet’s ionosphere. Bluer colors show infrared light from lower altitudes, including cloud tops in the atmosphere and the prominent Great Red Spot. Image credit: ESA/Webb, NASA & CSA, H. Melin, M. Zamani (ESA/Webb) CC BY 4.0 INT or ESA standard license
“One way to change this structure is through gravitational waves – similar to waves breaking on a beach and creating ripples in the sand,” explained Henrik. “These waves originate deep in the turbulent lower atmosphere around the Great Red Spot and can travel upwards, changing the structure and emissions of the upper atmosphere.”
The team explains that these atmospheric waves can occasionally be observed on Earth, but they are much weaker than the waves observed by Webb on Jupiter. They hope to conduct more Webb observations of these complex wave patterns in the future to study how the patterns move in the planet’s upper atmosphere and improve our understanding of the energy budget of this region and how its characteristics change over time.
These insights could also benefit ESA’s Jupiter Icy Moons Explorer Juice, launched on 14 April 2023. Juice will make detailed observations of Jupiter and its three large, ocean-bearing moons – Ganymede, Callisto and Europa – using a suite of remote sensing, geophysical and in situ instruments.
The mission will characterize these moons both as planetary objects and as possible habitats, explore Jupiter’s complex environment in depth, and investigate the wider Jupiter system as an archetype for gas giants throughout the universe.
These observations were conducted as part of Early Release Science program #1373: ERS observations of the Jupiter system as a demonstration of JWST’s capabilities in solar system science.
“This ERS proposal was written back in 2017,” explained team member Imke de Pater of the University of California, Berkeley. “One of our goals was to investigate why the temperature over the Great Red Spot appeared to be high, as recent observations with the NASA Infrared Telescope Facility had shown at the time. However, our new data showed very different results.”
More information:
Henrik Melin et al., Ionospheric irregularities at Jupiter observed by JWST, Natural astronomy (2024). DOI: 10.1038/s41550-024-02305-9
Information about the magazine:
Natural astronomy