Composite of JWST MIRI/MRS observations from November 2022 were utilized to analyze Saturn’s northern hemisphere and its ring system. The MIRI instrument is mainly sensitive to thermal variations; the colors represent a spectrum of temperature readings from the stratosphere to the lower troposphere. Filters for observing the rings were also employed to provide a more expansive field of view. For comparison, a visible-light capture from Hubble taken in September 2022 is integrated in the background. Credit: NASA, ESA, and researchers Amy Simon and Alyssa Pagan.
Recent studies on Saturn conducted by the University of Leicester’s planetary scientists via the James Webb Space Telescope (JWST) have shed new light on the iconic ringed planet.
The researchers have observed that Saturn’s late northern summer is transitioning into a cooler phase as the large-scale air currents on the planet have started to shift direction, heralding the onset of autumn.
Moreover, the latest imagery has offered a final look at Saturn’s northern polar region, characterized by a warm vortex rich in hydrocarbon gases, before it succumbs to the long, dark polar winter.
This celestial meteorological report is the outcome of an analysis carried out by the University of Leicester’s team, utilizing data from the JWST, and has been published in the Journal of Geophysical Research: Planets. These findings have enriched our understanding of the seasonal cycles on this gigantic, ringed planet.
Similar to Earth, Saturn also possesses an axial tilt and thus experiences seasons. However, a full orbit around the Sun takes Saturn 30 years, making each season last for approximately 7.5 years. As Earth approaches its northern autumn equinox in September, Saturn is projected to reach its own in 2025, plunging both planets’ northern poles into extended polar winters.
Table of Contents
Tools and Observations
The Mid-Infrared Instrument (MIRI) on the JWST was employed by the Leicester scientists to probe Saturn’s atmosphere in the infrared spectrum. This enables the measurement of temperatures, gas concentrations, and cloud activities from the tumultuous cloud tops to the high-altitude areas known as the stratosphere. The MIRI instrument segregates the infrared light into its constituent wavelengths, allowing the identification of various chemical compounds in the atmosphere.
The composite imagery generated from a subset of the MIRI observations prominently features thermal emissions from the north pole, displayed in blue hues. Additionally, the north polar cyclone, initially discovered by the Cassini mission, is visible, encircled by an extensive area of warm gases known as the north polar stratospheric vortex, which has remained stable throughout Saturn’s northern summer.
As autumn of 2025 nears, this stratospheric vortex is expected to cool down and gradually dissipate as the northern hemisphere enters a darker, colder phase.
Comparative Analysis and Inferences
Utilizing mid-infrared spectral models, the researchers discovered that Saturn’s current stratospheric temperature and gas distribution patterns are distinctly different from those recorded by the Cassini mission during the northern winter and spring. Previous circulatory patterns have now reversed, as evidenced by cooler stratospheric temperatures and reduced hydrocarbon levels in Saturn’s northern midlatitudes, implying the rising of hydrocarbon-deficient air during the summer, which is now moving southward.
Expert Commentary
Professor Leigh Fletcher, a member of the University of Leicester’s School of Physics and Astronomy, remarked on the exceptional quality of the new JWST data. He emphasized that this singular set of observations has extended the Cassini mission’s contributions into a novel Saturnian season, and expressed anticipation for future planetary studies.
Saturn was strategically chosen for early JWST observations to evaluate the telescope’s capabilities, as explained by Dr. Oliver King, a postdoctoral researcher. He also noted the challenges presented by Saturn’s luminosity and motion in relation to MIRI’s limited field of view.
Professor Fletcher added that the first batch of data, arriving after more than eight years of planning, represented a career milestone for the team, thanking the wider community of experts for their contributions.
He concluded by stating that this is hopefully just the beginning of JWST’s explorations, promising to further the scientific legacy initiated by the Cassini mission in the forthcoming decade.
Reference: “Saturn’s Atmosphere in Northern Summer Revealed by JWST/MIRI” by a consortium of researchers, Journal of Geophysical Research: Planets, 12 September 2023, DOI: 10.1029/2023JE007924.
Frequently Asked Questions (FAQs) about Saturn’s seasonal changes
What is the main focus of this article?
The main focus of this article is the new observations of Saturn made by the University of Leicester using the James Webb Space Telescope (JWST). These observations provide insights into the seasonal changes occurring on Saturn, particularly in its northern hemisphere as it transitions from summer to autumn.
What instrumentation was used for these observations?
The observations were conducted using the Mid-Infrared Instrument (MIRI) on the JWST. MIRI is sensitive to temperature changes and can split infrared light into its component wavelengths, allowing scientists to analyze the various chemicals in Saturn’s atmosphere.
What are some key findings about Saturn’s atmosphere?
The article reveals that Saturn’s late northern summer is experiencing a cooling trend. Planetary-scale air flows have reversed direction as autumn approaches. Additionally, it offers a last glimpse of Saturn’s north pole, featuring a warm vortex filled with hydrocarbon gases, before it recedes into the darkness of the polar winter.
How do Saturn’s seasons compare to Earth’s?
Like Earth, Saturn has an axial tilt and experiences seasons. However, Saturn takes 30 years to complete an orbit around the Sun, making each season last for approximately 7.5 Earth-years. Both planets are currently transitioning from summer to autumn in their respective northern hemispheres.
What does the article say about the data quality from the James Webb Space Telescope?
Experts from the University of Leicester commend the quality of the new data from JWST as “breath-taking.” The data extends the legacy of previous Saturn observations made by the Cassini mission and offers new possibilities for understanding weather patterns and atmospheric circulation on Saturn.
How do these observations compare to previous Cassini mission data?
The observations differ notably from data collected by the Cassini mission during Saturn’s northern winter and spring. For example, the large-scale stratospheric circulation pattern has now reversed, and cooler stratospheric temperatures along with low hydrocarbon abundances are seen in the northern midlatitudes.
Who were the main contributors to this research?
The main contributors to this research are from the University of Leicester School of Physics and Astronomy, particularly Professor Leigh Fletcher and Dr. Oliver King. Their work was published in the Journal of Geophysical Research: Planets.
Is this the first time Saturn’s late northern summer and autumn have been observed?
Yes, according to the article, no spacecraft has ever been present to explore Saturn’s late northern summer and autumn before. The new data from the James Webb Space Telescope is considered a starting point for further research into the coming decade.
More about Saturn’s seasonal changes
- James Webb Space Telescope Official Site
- University of Leicester School of Physics and Astronomy
- Journal of Geophysical Research: Planets
- Cassini Mission Overview
- NASA’s Overview on Saturn
- Mid-Infrared Instrument (MIRI) on JWST
7 comments
i can’t even wrap my head around a season lasting 7.5 years. Imagine having a 7 year long summer vacation lol.
Its all fascinating but let’s not forget to take care of our own planet too. Earth’s got it’s own share of climate issues.
Really impressed with how far we’ve come in terms of space observation. From Cassini to JWST, what a journey.
Kudos to the team at University of Leicester. Their work is opening up whole new avenues in planetary science. The quality of data JWST is providing is simply astounding!
Wow, this is next-level stuff! Who knew Saturn was so complicated. Autumn there must be really something.
The MIRI instrument sounds super advanced. Splitting infrared to see chemical components? That’s like CSI but for planets!
The James Webb Space Telescope is a game changer, no doubt. Cant wait to see what else it reveals about our solar system.