Using the James Webb Space Telescope, a joint effort of NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA), a group of scientists has discovered a series of never-before-seen features in Jupiter’s upper atmosphere. These features are located 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 latest observations of the region, scientists thought the region was unremarkable in nature and did not host any complex atmospheric structures or activity. However, Webb has shown that the region is scientifically interesting and is already providing scientists with greater insight into the inner workings of Jupiter and its enormous atmosphere.
While it may sound easy, observing Jupiter in great detail using huge telescopes like Webb and Hubble is difficult. The glow of Jupiter’s upper atmosphere is faint compared to that of 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 in the planet’s upper atmosphere. However, because Webb is sensitive to infrared light, the telescope is able to observe the upper atmosphere without interference from the planet’s bright polar regions. Additionally, Webb’s advanced design and size mean that it can not only collect data on the upper atmosphere, but do so in unprecedented detail.
Webb’s observations of the area surrounding 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 a boundary between the planet’s immense 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 the help of volcanic material ejected by the moon Io, produces brilliant northern and southern lights. However, closer to the planet’s equator, atmospheric structure is largely determined by incoming sunlight, and given that Jupiter receives only four percent of the sunlight received on Earth, scientists have predicted that this region would be less complex than regions further north and south. regions of the upper atmosphere.
However, this was merely a hypothesis by scientists, as the observations needed to determine the structure of the upper atmosphere in equatorial regions were not yet available – at least until Webb’s debut in 2022.
Webb first observed the equatorial regions of the upper atmosphere, specifically an area above the Great Red Spot, in July 2022 using the capabilities of the Near-Infrared Spectrograph (NIRSpec) instrument’s Integral Field Unit. The team of scientists’ primary goal with these observations was to study the region and determine if it was as dim as scientists had previously thought.
However, when Webb’s observations and data were sent back to the team, they were surprised to find that the entire region above the Great Red Spot hosts a variety of complex structures and activities, notably dark arcs and bright spots.
“We thought, perhaps naively, that this region would be really boring. It’s actually just as interesting, if not more so, than the Northern Lights. Jupiter never ceases to surprise,” said lead author Henrik Melin of the University of Leicester in the United Kingdom.
Much of the light emitted by this region consists of reflected sunlight. However, some of the structures and activities discovered in this area appear to be altered by a mechanism other than sunlight.
“One way to change this structure is to use gravitational waves, similar to those that crash on a beach and create ripples in the sand. These waves are generated deep in the turbulent lower atmosphere, all around the Great Red Spot, and they can travel aloft, changing the structure and emissions of the upper atmosphere,” Melin explained.
The atmosphere surrounding the Great Red Spot as imaged by NIRSpec. (Credit: ESA/Webb/NASA/CSA/H. Melin/M. Zamani (ESA/Webb))
Mélin et al. explain in their study that these atmospheric waves can sometimes be observed on Earth. However, the waves that occur on Earth are much weaker than those observed on Jupiter by Webb. The team plans to make follow-up observations of these atmospheric wave patterns to study how the waves move through Jupiter’s upper atmosphere. Additionally, understanding the wave patterns will give scientists a better understanding of how much energy is contained in this region and how the structures discovered by Webb evolve over time.
Webb’s latest observations will not only help scientists better understand the upper atmosphere of Jupiter, but will also help inform mission planning and future scientific observations for ESA’s JUICE (Jupiter Icy Moons Explorer) mission. JUICE is currently en route to Jupiter, where it will explore the planet’s three largest ocean moons, Ganymede, Callisto and Europa.
Melin et al.’s observations were taken as part of Webb’s 1373 Early Release Science (ERS) program. The observation proposal was written in 2017 and was originally written to understand the temperature above the Great Red Spot.
🆕 Scientists have discovered complex features above Jupiter’s famous Great 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 goals was to determine why the temperature above the Great Red Spot appeared to be high, as recent observations with the telescope revealed at the time. infrared from NASA. However, our new data showed very different results,” said Imke de Pater, study co-author and fellow at the University of California, Berkeley.
The results of Melin et al. were published in the journal Natural astronomy.
(Main image: Jupiter photographed in the near infrared by Webb’s NIRCam instrument. Credit: NASA/ESA/CSA/Jupiter ERS Team/Ricardo Hueso (UPV/EHU)/Judy Schmidt)