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Universe Today

Two space telescopes see Saturn in a different light

Views of Saturn captured by JWST (left) and Hubble (right).
NASA's James Webb Space Telescope acquired the infrared view of Saturn at left on Nov. 29, 2024. The Hubble Space Telescope's corresponding visible-light view, at right, was captured on Aug. 22, 2024. Credits: NASA, ESA, CSA, STScI, Amy Simon (NASA-GSFC), Michael Wong (UC Berkeley); Image Processing: Joseph DePasquale (STScI)

NASA is serving up a double scoop of delicious Saturn imagery in two flavors — near-infrared and visible light. The subtle differences between the James Webb Space Telescope’s infrared view and the Hubble Space Telescope’s visible-light view can help scientists dig deeper into the workings of the ringed planet’s atmosphere.

Both images were captured in the latter half of 2024 and released today. The Hubble image, produced as part of a 12-year-long monitoring program known as the Outer Planet Atmospheres Legacy, shows Saturn’s bands of clouds roughly as they’d appear to the naked eye.

In the JWST image, it’s easier to make out a long-lived jet stream known as the “Ribbon Wave” at northern mid-latitudes. Just below the wave, there’s a whitish speck that represents the remnant of the “Great Springtime Storm,” an atmospheric disturbance that made a huge impression from 2010 to 2012. Other storms show up as pockmarks in the clouds of the southern hemisphere.

Saturn’s poles take on a gray-green glint in the color-coded infrared view, which indicates light emissions in wavelengths around 4.3 microns. NASA says that could be due to a layer of high-altitude aerosols in Saturn’s atmosphere that scatters light differently at those latitudes. Auroral activity could serve as an alternate explanation.

The two images provide different views of Saturn’s rings as well. In JWST’s infrared view, the rings appear brighter due to the light reflected by water ice. The infrared view clearly shows the outermost ring, known as the F ring, which glows only slightly in the Hubble view.

Some of Saturn’s more than 250 moons make cameo appearances in the the images. You can make out Titan, Janus, Dione, Enceladus, Mimas and Tethys in JWST’s wide-angle view, while Hubble’s view highlights Janus, Epimetheus and Mimas (plus Mimas’ shadow).

These pictures were taken as Saturn approached last year’s equinox, and the views will keep changing with the seasons. “As Saturn transitions into southern spring, and later southern summer in the 2030s, Hubble and Webb will have progressively better views of that hemisphere,” NASA says in today’s image advisory.

Wide-angle JWST view of Saturn and its moons
A wide-angle version of the James Webb Space Telescope’s view of Saturn shows Titan, Janus, Dione, Enceladus, Mimas and Tethys. Click on the image for a larger version. Credits: NASA, ESA, CSA, STScI; Image Processing: Joseph DePasquale (STScI)

Hubble image of Saturn and moons
The Hubble Space Telescope’s view of Saturn also shows Janus, Mimas and Epimetheus, three of the ringed planet’s moons. Click on the image for a larger version. Credits: Image: NASA, ESA, STScI, Amy Simon (NASA-GSFC), Michael Wong (UC Berkeley); Image Processing: Joseph DePasquale (STScI)

This report was published on Universe Today with the headline “NASA’s Webb and Hubble Telescopes Look at Saturn in a Different Light.” Licensed for republication under Creative Commons Attribution 4.0 International License.

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Universe Today

Scientists find evidence of faraway worlds colliding

Illustration: Star with two planets colliding in orbit
An artist's conception shows a planetary collision around a star called Gaia20ehk. (Credit: Andy Tzanidakis / Univ. of Washington)

Astronomers say unusual readings from a star system 11,000 light-years away suggest that two of the planets circling the star crashed into each other, creating a huge, light-obscuring cloud of rocks and dust.

The analysis, laid out this week in a paper published by The Astrophysical Journal Letters, could provide new insights into the occasionally cataclysmic process that governs the evolution of planetary objects — including our own planet Earth and its moon.

“There are only a few other planetary collisions of any kind on record, and none that bear so many similarities to the impact that created the Earth and moon,” University of Washington graduate student Anastasios Tzanidakis, the study’s lead author, said in a news release. “If we can observe more moments like this elsewhere in the galaxy, it will teach us lots about the formation of our world.”

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Cosmic Space

A cousin for Pluto? New dwarf planet candidate found

Three images of 2017 OF201
Images captured by the Canada-France-Hawaii Telescope between August and November 2011 zero in on 2017 OF201. (Credit: Cheng et al.)

Astrophysicists say they’ve identified an object beyond the orbit of Neptune that’s likely to qualify as a dwarf planet, alongside other trans-Neptunian objects including Pluto, the erstwhile “ninth planet.”

The discovery of 2017 OF201 touches upon another ninth-planet controversy: namely, whether there’s a large planet nicknamed Planet 9 or Planet X lurking somewhere on the edges of the solar system.

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Cosmic Space

Webb Telescope detects activity within dwarf planets

Makemake and Eris
An artist's conception compares the size of 889-mile-wide Makemake and 1,445-mile-wide Eris. (SWRI Illustration)

They may be dwarf planets, but they’re not dead planets.

NASA’s James Webb Space Telescope has provided scientists with evidence of geothermal activity deep within two far-out dwarf planets, Eris and Makemake.

“We see some interesting signs of hot times in cool places,” Christopher Glein, an expert in planetary geochemistry at the Southwest Research Institute, said this week in a news release. Glein is the lead author of a study analyzing the JWST findings that was recently published by the journal Icarus.

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Cosmic Space

Webb Telescope captures its first photo of alien planet

This image shows the exoplanet HIP 65426 b in different bands of infrared light, as seen from the James Webb Space Telescope. In each of the infrared images, the planet's parent star is shown as a white five-pointed star. Credit: NASA/ESA/CSA, A. Carter (UCSC), the ERS 1386 team and A. Pagan (STScI).

NASA has released the first direct image of an exoplanet taken by the James Webb Space Telescope — and although there’s no chance that this particular alien world could harbor life as we know it, the picture serves as an early demonstration of the observatory’s power.

“We’ve only just begun,” Aarynn Carter, a researcher at the University of California at Santa Cruz who led the analysis of the JWST image, said today in a NASA image advisory. “There are many more images of exoplanets to come that will shape our overall understanding of their physics, chemistry and formation.”

The planet in question, HIP 65426 b, is about 355 light-years away in the constellation Centaurus. Discovered five years ago, it’s a gas giant that’s roughly seven times as massive as Jupiter — and it’s about 100 times farther out from its parent star than Earth is from the sun.

That extreme distance from a dwarf star would make HIP 65426 b a prohibitively chilly ball of gas. But the distance also provides enough separation for JWST to distinguish the planet from the star.

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Cosmic Space

Uranus and Enceladus top planetary scientists’ to-do list

Image: OCEANUS at Uranus
An artist's conception shows a probe called OCEANUS approaching Uranus. (Purdue Engineering)

Uranus has long been the butt of jokes, but the ice giant is finally getting its day in the sun, thanks to a recommendation in the National Academies’ newly released survey of potential interplanetary missions.

The decadal survey, drawn up by teams of scientists, serves as a roadmap for research in planetary science and astrobiology over the next 10 years. And the survey’s highest priority for multibillion-dollar flagship missions is to send an orbiter and a piggyback atmospheric probe to Uranus (preferably pronounced “urine-us,” not “your-anus”). Launch would come as early as 2031 or 2032, when the orbital mechanics are optimal for a multibillion-mile cruise.

In preparation for this decadal survey, a team of scientists led by NASA and the Jet Propulsion Laboratory drew up preliminary plans for a mission to Uranus or its ice-giant neighbor, Neptune.  Separately, Purdue University researchers developed a mission concept called OCEANUS (Observatory Capture Exploring the Atmospheric Nature of Uranus and Neptune) that included a Saturn flyby as well as a years-long study of Uranus.

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Cosmic Space

Astronomers detect first hints of extragalactic planet

Suspected planet in M51
The white square highlights the suspected planet in M51. (NASA / CXC / SAO / DiStefano et al.; Optical: NASA / ESA / STScI / Grendler)

A blip recorded by the NASA’s Chandra X-ray Observatory has pointed astronomers to what might be a planet detected passing across a star in a galaxy beyond our own — but we may not know for sure anytime soon.

The observation of an X-ray transit in the spiral galaxy M51, about 28 million light-years away in the northern constellation Canes Venatici, is reported in the journal Nature Astronomy.

Even if the detection of a planet in M51 goes unconfirmed, the Chandra observations demonstrate that X-ray transits could become a new method for tracking planets far beyond our solar system.

“We are trying to open up a whole new arena for finding other worlds by searching for planet candidates at X-ray wavelengths, a strategy that makes it possible to discover them in other galaxies,” Rosanne Di Stefano of the Harvard-Smithsonian Center for Astrophysics, lead author of the newly published study, said in a news release.

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Cosmic Space

Jupiter and Saturn pair up to make a Christmas Star

Jupiter and Saturn
Ths graphic shows how Jupiter and Saturn line up in the sky as seen from mid-northern latitudes. (Sky & Telescope Illustration)

Are you ready for a remake of the Christmas Star story? Depending on how much stock you put in historical hypotheses, this year’s solstice on Dec. 21 could bring a replay of the phenomenon that the Three Kings saw in the Gospel of Matthew.

That’s when Jupiter and Saturn can be seen incredibly close together in the night sky. If the skies are clear, the two planets will be hard to miss in southwest skies just after sunset, as seen from mid-northern latitudes. Jupiter will sparkle brighter, and Saturn will be shining only a tenth of a degree to the upper right. With a small telescope, you might be able to see both planets and their moons in a single field of view.

“Some astronomers suggest the pair will look like an elongated star, and others say the two planets will form a double planet,” NASA says in a blog posting about the Dec. 21 conjunction. “To know for sure, we’ll just have to look and see. Either way, take advantage of this opportunity because Jupiter and Saturn won’t appear this close in the sky until 2080!”

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GeekWire

Solving the case of the disappearing planet

More than a decade ago, Fomalhaut b was considered one of the first exoplanets to be directly imaged — but now it’s vanished, and scientists suspect it was actually nothing more than a huge cloud of dust created by a cosmic smashup.

Get the news brief on GeekWire.

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GeekWire

New Earth-sized planet ‘rescued’ from old data

Exoplanet
An artist’s conception shows Kepler-1649c orbiting around its host red dwarf star. (NASA / Ames Research Center Illustration / Daniel Rutter)

An alien Earth that just might be habitable has been discovered in years-old records, thanks to sharp-eyed astronomers who gave the data a second look.

Get the news brief on GeekWire.