Using the joint NASA, European Space Agency (ESA) and Canadian Space Agency (CSA) James Webb Space Telescope, a team of scientists has discovered a number of never-before-seen features in Jupiter’s upper atmosphere. The features were found in the atmospheric region above the iconic Great Red Spot – a high-pressure region in Jupiter’s atmosphere that produces a massive anticyclonic storm that has been visible to astronomers since 1831.
Before the recent observations of the region, scientists believed that the region was exceptional in nature and lacked any complex atmospheric structure or activity. However, Webb has shown that the region is scientifically interesting and is already providing scientists with more insight into Jupiter’s inner workings and its vast atmosphere.
While it may seem easy, observing Jupiter in great detail using large telescopes like the Webb and Hubble is difficult. The glow from Jupiter’s upper atmosphere is faint compared to the glow from the planet’s north and south polar regions, meaning that visible light telescopes like Hubble and some ground-based telescopes have a harder time observing specific structures within the planet’s upper atmosphere. However, given Webb’s sensitivity to infrared light, the telescope is able to observe the upper atmosphere without interference from the planet’s bright polar regions. Furthermore, Webb’s advanced engineering and size mean that it can not only collect data on the upper atmosphere, but do so in unprecedented detail.
Web observations of the area around the Great Red Spot. (Credit: ESA/Webb/NASA/CSA/Jupiter ERS Team/J. Schmidt/H. Melin/M. Zamani (ESA/Webb))
Jupiter’s upper atmosphere serves as the boundary between the planet’s large magnetic field and the inner atmosphere, and its structure is largely shaped by the interaction between the two regions. For example, the upper atmosphere, with some help from volcanic material ejected from the moon Io, produces bright northern and southern lights. Closer to the planet’s equator, however, the atmospheric structure is largely determined by incoming sunlight, and given that Jupiter receives only four percent of the sunlight received on Earth, scientists predicted that this region would be less complex than the northernmost and the southernmost. the upper regions of the atmosphere.
However, this was just a hypothesis from scientists, since the observations needed to determine the structure of the upper atmosphere in the equatorial regions were not yet available – that was until Webb’s debut in 2022.
Webb first observed the equatorial regions of the upper atmosphere, specifically an area located above the Great Red Spot, in July 2022 using the capabilities of the Near Infrared Spectroscopy Instrument’s Integral Field Unit (NIRSpec). The main goal of the team of scientists with the observations was to investigate the region and determine if the region was dull as previously thought by scientists.
When Webb’s observations and data were returned to the team, however, they were surprised to see that the entire region above the Great Red Spot hosts a variety of complex structures and activity, including dark arcs and bright spots.
“We thought this region, perhaps naively, would be really boring. It is, in fact, just as interesting as the northern lights, if not more so. Jupiter never ceases to amaze,” said lead author Henrik Melin of the University of Leicester in the United Kingdom.
Most of the light emitted from this region is reflected by sunlight, however, some of the structures and activity detected in this area appear to have been altered by some mechanism other than sunlight.
“One way you can change this structure is by gravity waves – similar to waves crashing on a beach, creating ripples in the sand. These waves are created deep in the turbulent lower atmosphere, all around the Great Red Spot, and they can travel up in altitude, changing the structure and emissions of the upper atmosphere,” explained Melin.
The atmosphere surrounding the Great Red Spot as imaged by NIRSpec. (Credit: ESA/Webb/NASA/CSA/H. Melin/M. Zamani (ESA/Webb))
Melin etc. explain in their study that these atmospheric waves can sometimes be observed on Earth. However, the waves occurring on Earth are much weaker than those observed on Jupiter by Webb. The team plans to conduct follow-up observations of these atmospheric wave patterns to investigate how the waves move through Jupiter’s upper atmosphere. Additionally, understanding the wave patterns will allow scientists to develop an understanding of how much energy is held in this region and how the structures discovered by Webb change over time.
Webb’s latest observations not only expand scientists’ understanding of the Jovian upper atmosphere, but will also help inform mission planning and future science observations on ESA’s Jupiter Icy Moons Explorer, or JUICE, mission -s. JUICE is currently en route to Jupiter, where it will explore the planet’s three largest ocean-bearing moons, Ganymede, Callisto and Europa.
The observations of Melin et al. were taken as part of Webb’s Early Release Science (ERS) program 1373. The proposal for the observations was written in 2017 and was originally written to understand the temperature above the Great Red Spot.
🆕 Scientists have found complicated features on Jupiter’s famous Red Spot! Read more: https://t.co/wHAiYBap2l or 🧵👇 pic.twitter.com/71J9ToJGIH
— ESA Webb Telescope (@ESA_Webb) June 25, 2024
“This ERS proposal was written in 2017. One of our objectives had been to investigate why the temperature above the Great Red Spot appeared to be high, as they had discovered at the time when the last observations with the Infrared Telescope Facility of NASA had discovered. However, our new data showed very different results,” said co-author Imke de Pater from the University of California, Berkeley.
The results of Melin et al. were published in the magazine Astronomy of Nature.
(Main image: Jupiter imaged in the near infrared by Webb’s NIRCam instrument. Credit: NASA/ESA/CSA/Jupiter ERS Team/Ricardo Hueso (UPV/EHU)/Judy Schmidt)