Showing posts with label Dione. Show all posts
Showing posts with label Dione. Show all posts

Saturday, March 28, 2026

NASA Webb, Hubble Share Most Comprehensive View of Saturn to Date

Saturn (Webb NIRCam and Hubble WFC3/UVIS)
Complementary views of Saturn from NASA’s James Webb Space Telescope and Hubble Space Telescope show a dynamic planet with atmospheric features, orbiting moons, and bright rings. Credit Image: NASA, ESA, CSA, STScI, Amy Simon (NASA-GSFC), Michael Wong (UC Berkeley); Image Processing: Joseph DePasquale (STScI)

Captured Nov. 29, 2024 by NASA’s James Webb Space Telescope, this infrared view of Saturn shows its glowing icy rings and layered atmosphere. Several moons are visible, including Janus, Dione, and Enceladus. Credit Image: NASA, ESA, CSA, STScI, Amy Simon (NASA-GSFC), Michael Wong (UC Berkeley); Image Processing: Joseph DePasquale (STScI)

Captured Aug. 22, 2024 by NASA’s Hubble Space Telescope, this visible-light view of Saturn reveals the planet’s softly banded atmosphere and iconic rings. Several moons are also visible, labeled Janus, Mimas, and Epimetheus. Credit Image: NASA, ESA, CSA, STScI; Image Processing: Joseph DePasquale (STScI)

A wider view of Saturn from NASA’s James Webb Space Telescope shows six of Saturn’s larger moons, including the largest, Titan, at far left. Credit Image: NASA, ESA, STScI, Amy Simon (NASA-GSFC), Michael Wong (UC Berkeley); Image Processing: Joseph DePasquale (STScI)

These images of Saturn, captured by NASA’s James Webb and Hubble Spaces Telescopes, shows compass arrows, scale bar, and color key for reference. Credit Image: NASA, ESA, CSA, STScI; Image Processing: Joseph DePasquale (STScI)



NASA’s James Webb Space Telescope and Hubble Space Telescope have teamed up to capture new views of Saturn, revealing the planet in strikingly different ways. Observing in complementary wavelengths of light, the two space observatories provide scientists with a richer, more layered understanding of the gas giant’s atmosphere.

Both sense sunlight reflected from Saturn’s banded clouds and hazes, but where Hubble reveals subtle color variations across the planet, Webb’s infrared view senses clouds and chemicals at many different depths in the atmosphere, from the deep clouds to the tenuous upper atmosphere.

Together, scientists can effectively ‘slice’ through Saturn’s atmosphere at multiple altitudes, like peeling back the layers of an onion. Each telescope tells a different part of Saturn’s story, and the observations together help researchers understand how Saturn’s atmosphere works as a connected three-dimensional system. Both complement previous observations done by NASA’s Cassini orbiter during its time studying the Saturnian system from 1997 to 2017.

The Hubble image seen here was captured as part of a more than a decade long monitoring program called OPAL (Outer Planet Atmospheres Legacy) in August 2024, while the Webb image was captured a few months later using Director’s Discretionary Time.

The newly released images highlight features from Saturn’s busy atmosphere.

In the Webb image, a long-lived jet stream known as the “ribbon wave” meanders across the northern mid-latitudes, influenced by otherwise undetectable atmospheric waves. Just below that, a small spot represents a lingering remnant from the “Great Springtime Storm” of 2010 to 2012. Several other storms dotting the southern hemisphere of Saturn are visible in Webb’s image, as well.

All these features are shaped by powerful winds and waves beneath the visible cloud deck, making Saturn a natural laboratory for studying fluid dynamics under extreme conditions.

Several of the pointed edges of Saturn’s iconic hexagon-shaped jet stream at its north pole, discovered by NASA’s Voyager spacecraft in 1981, are also faintly visible in both images. It remains one of the solar system’s most intriguing weather patterns. Its persistence over decades highlights the stability of certain large-scale atmospheric processes on giant planets. These are likely the last high-resolution looks we’ll see of the famous hexagon until the 2040’s, as the northern pole enters winter and will shift into darkness for 15 years.

In Webb’s infrared observations, Saturn’s poles appear distinctly grey-green, indicating light emitting at wavelengths around 4.3 microns. This distinct feature could come from a layer of high-altitude aerosols in Saturn’s atmosphere that scatters light differently at those latitudes. Another possible explanation is auroral activity, as charged molecules interacting with the planet’s magnetic field can produce glowing emissions near the poles.

NASA’s Hubble and Webb have already explored Saturn’s auroras, provided insights into Jupiter’s spectacular auroras also seen with Hubble, confirmed the auroras of Uranus glimpsed in 2011 by Hubble, and detected Neptune’s auroras for the first time with Webb.

In Webb’s infrared image, the rings are extremely bright because they are made of highly reflective water ice. In both images, we’re seeing the sunlit face of the rings, a little less so in the Hubble image, hence the shadows visible underneath on the planet.

There are also subtle ring features such as spokes and structure in the B ring (the thick central region of the rings) that appear differently between the two observatories. The F ring, the outermost ring, looks thin and crisp in the Webb image, while it only slightly glows in the Hubble image..

Saturn’s orbit around the Sun, combined with the position of Earth in its annual orbit, determines our changing viewing angle of Saturn’s face and ring.

These 2024 observations, taken 14 weeks apart, show the planet moving from northern summer toward the 2025 equinox. As Saturn transitions into southern spring, and later southern summer in the 2030’s, Hubble and Webb will have progressively better views of that hemisphere.

Hubble’s observations of Saturn for decades have built a record of its evolving atmosphere. Programs like OPAL, with its annual monitoring, are allowing scientists to track storms, banding patterns, and seasonal shifts over time. Webb now adds powerful infrared capabilities to this ongoing record, extending what researchers can measure about Saturn’s atmospheric structure and dynamic processes.

The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).




Details:

Last Updated: Mar 26, 2026
Location:
NASA Goddard Space Flight Center

Contact Media:

Laura Betz
NASA’s Goddard Space Flight Center
Greenbelt, Maryland

laura.e.betz@nasa.gov

Hannah Braun
Space Telescope Science Institute
Baltimore, Maryland


Christine Pulliam
Space Telescope Science Institute
Baltimore, Maryland




Saturday, March 03, 2012

Cassini Detects Hint of Fresh Air at Dione

This view highlights tectonic faults and craters on Dione, an icy world that has undoubtedly experienced geologic activity since its formation. Image credit: NASA/JPL/Space Science Institute. Full image and caption

NASA's Cassini spacecraft has "sniffed" molecular oxygen ions around Saturn's icy moon Dione for the first time, confirming the presence of a very tenuous atmosphere. The oxygen ions are quite sparse - one for every 0.67 cubic inches of space (one for every 11 cubic centimeters of space) or about 2,550 per cubic foot (90,000 per cubic meter) - show that Dione has an extremely thin neutral atmosphere.

At the Dione surface, this atmosphere would only be as dense as Earth's atmosphere 300 miles (480 kilometers) above the surface. The detection of this faint atmosphere, known as an exosphere, is described in a recent issue of the journal Geophysical Research Letters.

"We now know that Dione, in addition to Saturn's rings and the moon Rhea, is a source of oxygen molecules," said Robert Tokar, a Cassini team member based at Los Alamos National Laboratory, Los Alamos, N.M., and the lead author of the paper. "This shows that molecular oxygen is actually common in the Saturn system and reinforces that it can come from a process that doesn't involve life."

Dione's oxygen appears to derive from either solar photons or energetic particles from space bombarding the moon's water ice surface and liberating oxygen molecules, Tokar said. But scientists will be looking for other processes, including geological ones, that could also explain the oxygen.

"Scientists weren't even sure Dione would be big enough to hang on to an exosphere, but this new research shows that Dione is even more interesting than we previously thought," said Amanda Hendrix, Cassini deputy project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif., who was not directly involved in the study. "Scientists are now digging through Cassini data on Dione to look at this moon in more detail."

Several solid solar system bodies - including Earth, Venus, Mars and Saturn's largest moon Titan - have atmospheres. But they tend to be typically much denser than what has been found around Dione. However, Cassini scientists did detect a thin exosphere around Saturn's moon Rhea in 2010, very similar to Dione. The density of oxygen at the surfaces of Dione and Rhea is around 5 trillion times less dense than that at Earth's surface.

Tokar said scientists suspected molecular oxygen would exist at Dione because NASA's Hubble Space Telescope detected ozone. But they didn't know for sure until Cassini was able to measure ionized molecular oxygen on its second flyby of Dione on April 7, 2010 with the Cassini plasma spectrometer. On that flyby, the spacecraft flew within about 313 miles (503 kilometers) of the moon's surface.

Cassini scientists are also analyzing data from Cassini's ion and neutral mass spectrometer from a very close flyby on Dec. 12, 2011. The ion and neutral mass spectrometer made the detection of Rhea's thin atmosphere, so scientists will be able to compare Cassini data from the two moons and see if there are other molecules in Dione's exosphere.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency, and the Italian Space Agency. NASA's Jet Propulsion Laboratory, Pasadena, CLinkalif., a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The Cassini plasma spectrometer team and the ion and neutral mass spectrometer team are based at Southwest Research Institute, San Antonio.

For more information about the Cassini mission, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jia-rui.c.cook@jpl.nasa.gov